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Clinical Course and Genetic Susceptibility of Primary Biliary Cirrhosis: Analysis of a Prospective Cohort

AUTHORS

Piero Luigi Almasio 1 , * , Anna Licata 1 , Marcello Maida 1 , Fabio Salvatore Macaluso 1 , Andrea Costantino 1 , Nicola Alessi 1 , Stefania Grimaudo 1 , Giulia Accardi 2 , Calogero Caruso 2 , Antonio Craxi 1

AUTHORS INFORMATION

1 Sezione di Gastroenterologia ed Epatologia, Dipartimento Biomedico di Medicina Interna e Specialistica, University of Palermo, Palermo, Italy

2 Dipartimento di Biopatologia e Biotecnologie Mediche, University of Palermo, Palermo, Italy

How to Cite: Almasio P L, Licata A, Maida M, Macaluso F S, Costantino A, et al. Clinical Course and Genetic Susceptibility of Primary Biliary Cirrhosis: Analysis of a Prospective Cohort, Hepat Mon. 2016 ; 16(11):e31681. doi: 10.5812/hepatmon.31681.

ARTICLE INFORMATION

Hepatitis Monthly: 16 (11); e31681
Published Online: October 16, 2016
Article Type: Research Article
Received: July 20, 2015
Revised: November 28, 2015
Accepted: December 19, 2015
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Abstract

Background: Natural history of primary biliary cirrhosis (PBC) is partially characterized in patients from the Mediterranean area whose genetic background differs from that of Northern Europeans.

Objectives: We aimed to describe genetic susceptibility and clinical course of PBC in patients from Southern Italy.

Methods: Socio-demographic, clinical, biochemical and histological data at diagnosis as well as disease progression of 81 PBC consecutive patients were collected. All subjects were treated with Ursodeoxycholic acid at a dose of 15 mg/kg. HLA class II DRB1 alleles were compared with those of 237 healthy control subjects. IL28B genotyping for IL28B rs12979860 C/T and rs80899917 G/T was performed in a sub-group of patients.

Results: HLA-DRB1*07 (RR 5.3, P = 0.0008) and HLA-DRB1*08 (RR n.c. P = 0.0005) were significantly associated with the risk of PBC development. Patients younger than 45 years had significantly higher alanine aminotransferase (P = 0.038) and alkaline phosphatase levels (P = 0.047) than older cases. In comparison to non-CC rs12979860, patients with CC rs12979860 genotype showed an early histological stage at onset (93.8% vs. 62.5%, P = 0.03). After a mean follow-up of 61 months, three patients died, one underwent liver transplantation and sixteen (21.9%) had progression of the disease. At multivariate analysis, extrahepatic autoimmune disease (P = 0.04), pruritus (P = 0.008) and advanced histological stage (P < 0.0001) were independent risk factors for disease progression.

Conclusions: HLA-DRB1*07 and HLA-DRB1*08 alleles increase susceptibility to disease development. At onset, higher biochemical activity was observed in younger patients, whereas rs12979860 CC genotype was associated with milder histological stage. Pruritus and coexistence of extrahepatic autoimmune diseases were significantly associated with poorer prognosis.

Keywords

Primary Biliary Cirrhosis Natural History Genetic

Copyright © 2016, Kowsar Corp. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited.

1. Background

Primary biliary cirrhosis (PBC) is a chronic cholestatic autoimmune disease of unknown etiology that mainly targets cholangiocytes of interlobular bile ducts. It primarily affects middle-aged women between the 5th and 6th decade, with a female/male ratio of 10:1. The disease has a slowly progressive course towards liver cirrhosis and death with a strong individual variability of progression rate. Currently, Ursodeoxycholic Acid (UDCA) is the only drug specifically approved for the treatment of PBC (1).

Incidence of PBC is extremely variable, ranging from 0.7 per million to a maximum average of 49 per million per year registered in Olmsted County, Minnesota (2). It seems that prevalence and incidence of the disease is increasing worldwide (3); this finding may be influenced by an increased exposure to potential environmental triggers or simply may be the result of a greater awareness of the disease amongst physicians.

Even if the pathogenesis of the disease is still unclear, it most likely results from a combination of genetic factors and superimposed environmental triggers. The role of genetic susceptibility is clear, as demonstrated by a 100-fold higher risk of developing PBC in relatives and a 60% concordance in monozygotic twins (4). Furthermore, a weak susceptibility conferred by the DRB1*08 allele of the human leukocyte antigen (HLA) class II (5) and a protective effect related to HLA DRB1*11 and DRB1*13 alleles have been demonstrated in Italian and UK series (6, 7). More interestingly, several components of an innate and adaptive immune system have been shown to play a critical role in establishing a greater susceptibility to PBC, as clearly stated by recent genome-wide association studies (GWAS) (8-12). Finally, a possible role of environmental triggers, such as infectious agents, xenobiotics, reproductive hormone replacement therapy and cigarette smoking, has been advocated, even if none of them has been definitively confirmed (13-16).

Few population-based studies on epidemiology and natural history of PBC have been conducted (17-21) and only three (19-21) of them are in the past decade. In particular, very few data exists on patients from the Mediterranean area, whose genetic background and risk factors might differ from those of other populations of Northern Europe and of Northern Italians (22).

In addition, there is no current data regarding a potential association between the clinical course of PBC and Interleukin (IL) 28B polymorphisms, whose rs12979860 CC and rs8099917 TT genotypes strongly predict the spontaneous clearance of HCV infection and the sustained virologic response after antiviral therapy in patients with chronic hepatitis C (23). Recently, our group has shown a link between IL28B polymorphisms and severity of liver disease in terms of both necroinflammatory activity and fibrosis in 160 patients suffering from non-alcoholic steatohepatitis (24). Although IL-28 is involved in immune defense against viruses, it also plays a role in the adaptive immune response, as its inclusion as an immunoadjuvant during animals vaccination leads to augmented antigen-specific Interferon Gamma (IFN-γ) release as well as an increased cytotoxic potential in CD8+ T cells (25, 26).

2. Objectives

The aim of our study was to perform a cohort study to describe genetic susceptibility and clinical course of PBC in patients from Southern Italy. In addition, a subgroup analysis was carried out to assess the potential impact of IL28B polymorphisms on the clinical expression of the disease.

3. Methods

3.1. Patients

This study was carried out on a sample of 81 consecutive patients with PBC who were recruited at the gastroenterology and liver unit of Azienda Ospedaliera Policlinico Universitario P. Giaccone of Palermo, Italy, from January 2001. Patients were included if they had a diagnosis of PBC according to the American association for the study of liver diseases (AASLD) guidelines (27), based on the presence of two out of three of the following criterias: (i) biochemical evidence of cholestasis with elevation of alkaline phosphatase activity; (ii) presence of anti-mithocondrial autoantibodies (AMA) positivity with titer ≥ 1: 40; (iii) histopathologic evidence of non-suppurative cholangitis and destruction of small or medium-sized bile ducts.

Histological staging, available in 77 patients, was performed according to Scheuer’s classification. Four patients did not undergo liver biopsy because of advanced age.

The exclusion criterias were: (i) other causes of liver disease or mixed etiologies, including overlap syndromes; (ii) significant alcohol consumption, i.e. superior to 21 alcohol units per week in men and 7 - 14 alcohol units per week in women (28), evaluated by interview (iii) HIV infection; (iiii) geographical origin outside Mediterranean area (Figure 1).

Clinical and biochemical data was collected at the time of the diagnosis and then every 6 months. The diagnosis of extrahepatic autoimmune diseases was made on clinical grounds following the diagnostic criteria commonly used for each single rheumatologic condition, without any grading/staging of the diseases. The presence of symptoms was assessed by interview. Patients with PBC-related symptoms (itching, jaundice, fatigue) or with symptoms ascribable to the autoimmune diseases associated with PBC (xerostomia, xerophthalmia, joint pain) were defined as symptomatic.

3.2. HLA Class II Genotyping

In a subgroup of PBC patients (n = 31), normally distributed for age, clinical presentation and histological stage, DNA typing of HLA class II alleles of Major Histocompatibility Complex (MHC) was performed using the MicroSSP DNA Typing trays by One Lambda (Canoga Park CA, USA). Firstly, the DNA was extracted from 200 μL of whole peripheral blood using the PureLink Genomic DNA Kit (Invitrogen by Life technologies) according to the manufacturer’s instructions. Secondly, DNA genotyping was performed by a single polymerase chain reaction (PCR) sequence specific primer (SSP) in accordance with the protocol, which was provided by the manufacturers (One Lambda, Canoga Park CA, USA). This method permits to discriminate each allelic difference overtaking the problem of possible ambiguous results linked to the cross-reagent group, typical of serological typing. The PCR products were separated on 2% agarose gel containing ethidium bromide and visualized under ultraviolet light. HLA class II DRB1 alleles were also genotyped in a control group of healthy subjects (n = 237) with the same method (MicroSSP DNA typing trays by one lambda). These patients belonged to the same population in terms of geographic distribution. Moreover, the selected subjects grandparents were all born in the Western part of Sicily. For this control group we used the entire reference of the healthy blood donor population.

3.3. IL28B Genotyping

IL28B genotyping for rs12979860 and rs8099917 polymorphisms was carried out in a subgroup of patients (n = 32). DNA was purified from whole-blood patient samples using the QIAmp DNA blood mini kit (Qiagen, Mainz, Germany). DNA samples were quantified using the Quant-iT™ PicoGreen® dsDNA Assay Kit (Invitrogen, Pasley, UK) and stored at 20°C. Genotyping for rs12979860 and rs8099917 was carried out using the TaqMan SNP genotyping allelic discrimination method (Applied Biosystems, Foster City, CA, USA). A commercial genotyping assay was available for the rs8099917 (cat. C_11710096_10), while a custom assay was created by AB for rs12979860.

3.4. Follow-Up and Treatment

A liver ultrasound was performed at the diagnosis and then annually in pre-cirrhotic patients as well as every 6 months in cirrhotic patients. Later, an esophagogastroduodenoscopy was performed every 1 - 3 years. Furthermore, patients with medium to large esophageal varices underwent primary prophylaxis of variceal bleeding according to the BAVENO V guidelines (29).

All patients were treated with UDCA (average dose: 15 mg/kg/day). In absence of the biochemical response to UDCA, as defined by the Barcelona or Paris criteria (30), either budesonide, fenofibrate or colchicine were added to UDCA.

Out of 81 patients, eight were lost during the follow-up. The other 73 patients were followed up for a period of at least one year. Disease progression was defined as the development of one or more of the following complications: esophageal varices, ascites, sonographic signs of portal hypertension, portosystemic encephalopathy, hepatocellular carcinoma (HCC), orthotopic liver transplantation (OLT) and death.

3.5. Ethical Approval

This study was performed in accordance with the principles of the declaration of Helsinki and its appendices as well as with the local and national laws. Approval was obtained from the hospital’s internal review board and the ethical committee, as well as written informed consent from all patients.

3.6. Statistical Analysis

Continuous variables were summarized as mean ± standard deviation and categorical variables as frequency and percentage. Mann-Whitney or χ2 tests were used as appropriate to compare continuous or categorical variables.

All patients were divided into groups, according to presence or absence of extrahepatic autoimmune disease and then to presence or absence of AMA positivity, in order to analyze statistically significant differences in terms of clinical presentation and laboratory tests. In addition, they were divided in three age groups (< 45 years, 45 - 65 years, > 65 years) in order to perform a similar comparison.

Typing of HLA class II DRB1 alleles, performed in 31 PBC patients, was compared with that of 237 healthy control subjects. The relative risk was calculated using Fischer’s test and Bonferroni correction method. After IL28B genotyping for rs12979860 and rs8099917 polymorphisms (n = 32), clinical, laboratory and histological features as well as disease progression of CC vs. non-CC rs12979860 and TT vs. non-TT rs8099917 patients were compared.

A Cox regression analysis was performed to identify the presence of independent predictors of clinical progression. A multivariate analysis including all the significant baseline variables (P < 0.05) was also conducted using a binary logistic regression.

All statistical analysis were performed using a SPSS v. 20.0 for Macintosh (SPSS Inc., Chicago, USA).

4. Results

4.1. Baseline Features

Baseline demographic, laboratory, clinic, histologic and genetic characteristics of 81 patients with PBC are summarized in Table 1. The mean age was 53.2 years (range 31 - 84), with a strong predominance of female sex (96.3%). Fourteen patients (17.3%) were diagnosed over the age of 65 years. Median gamma-glutamyl transpeptidase (GGT) values were five times the upper limit of normal (X u.l.n.) and those of alkaline phosphatase (AP) 3 X u.l.n. Median values of aspartate and alanine transferase (AST and ALT) were slightly higher than normal, even if 24 patients (24.6%) had values more than 2 X u.l.n. The median value of total cholesterol was 213 mg/dL with an interquartile range between 199 and 244 mg/dL.

Table 1. Baseline Demographic, Laboratory, Clinic, Histologic Characteristics of 81 Patients with Primary Biliary Cirrhosisa
Characteristics
Age - years, mean ± SD (range)53.2 ± 12.2 (31 - 84)
Female gender78 (96.3)
Antimitocondrial Antibodies (AMA)71 (87.7)
Antinuclear Antibodies (ANA)31 (38.3)
Smooth Muscle Antibodies (SMA)6 (7.4)
γ-Glutamyl Transpeptidase (IU/L), median (I.Q.I.)164 (83 - 322)
Alkaline Phosphatase (IU/L), median (I.Q.I.)297 (160 - 425)
Aspartate Aminotransferase (IU/L), median (I.Q.I.)41 (33 - 70)
Alanine Aminotransferase (IU/L), median (I.Q.I.)48 (34 - 80)
Total Bilirubin (mg/dL), mean ± SD0.76 ± 0.7
Platelets (x103/mmc), mean ± SD242 ± 84.5
Symptomatics54 (66.7)
Pruritus42 (51.6)
Fatigue13 (16.1)
Xerostomia13 (16.1)
Xerophtalmia11 (13.6)
Arthralgias3 (3.7)
Right upper abdominal quadrant discomfort3 (3.7)
Extrahepatic autoimmune diseases33 (40.7)
Sjogren’s Syndrome22 (27.2)
Autoimmune Thyroiditis7 (8.6)
Rheumatoid arthritis3 (3.7)
Seronegative Spondyloarthritis1 (1.2)
Liver Histology (n = 77)
Stage I15 (19.5)
Stage II40 (51.9)
Early (I - II)55 (71.4)
Stage III13 (16.9)
Stage IV9 (11.7)
Advanced (III - IV)22 (28.6)

aValues are expressed as No. (%) unless otherwise indicated.

Seventy-one out of eighty-one (87.7%) patients showed AMA positivity with titer ≥ 1:40, while ten were AMA negative. Amongst these, seven (12.3%) showed antinuclear autoantibodies (ANA) positivity with titer ≥ 1:80, two ANA and smooth muscle antibodies (SMA) positivity and one SMA positivity only. Comparing PBC AMA-positive and PBC AMA-negative cases, no significant differences regarding age and laboratory features at onset were found (data not shown).

Liver biopsy was performed in 77 out of 81 patients. Amongst these, 71.4% presented an early histological stage (Scheuer stage I and II) and 28.6% an advanced stage (Scheuer stage III and IV).

Two thirds of patients were symptomatic at the time of diagnosis. Most common symptoms were: pruritus (51.6%), asthenia (16.1%), xerostomia (16.1%), xerophthalmia (13.6%), arthralgia (3.7%) and right upper abdominal quadrant discomfort (3.7%). Thirty-three (40.7%) patients had extrahepatic autoimmune diseases associated with PBC. Amongst these, the most frequent one was Sjogren’s syndrome (27.2%). No significant differences were found on the clinical presentation and laboratory tests between patients with and without extrahepatic autoimmune diseases.

The comparison of the three groups of patients that were distributed according to age (< 45 years, n = 24, 45-65 years, n = 43, > 65 years, n = 14) showed that subjects younger than 45 years had higher ALT (P = 0.038) and AP levels (P = 0.047) than older cases (Table 2).

Table 2. Comparison Between Groups of Age (< 45 Years, n = 24; 45 - 65 Years, n = 43; > 65 years, n = 14) on Laboratory Characteristics at Onset: Univariate Analysis
Variable< 45 years, (n = 24)45 - 65 years, (n = 43)> 65 years, (n = 14)P
ALT (IU/L), median (I.Q.I.)62 (47 - 99)44 (32 - 71)33 (22 - 71)0.038
ALT (x u.l.n.), median (range)2xN (1.1 - 8.4)1.5xN (0.3 - 8.5)1xN (0.71 - 4.6)
AP (IU/L), median (I.Q.I.)411 (247 - 563)296 (115 - 408)165 (93 - 271)0.047
AP (x u.l.n.), median (range)4xN (1.4 - 21)3xN (0.5 - 9)1.5xN (0.4 - 4.4)

Abbreviations: ALT, Alanine aminotransferase; AP, Alkaline phosphatase.

4.2. Subgroup Analysis for IL28B Polymorphisms

Aiming to better define the genetic profile of our Mediterranean PBC cohort and considering the pivotal role of IL28B polymorphisms in modulating inflammatory response and progression of liver disease in different clinical settings, we decided to test a small number of PBC patients for IL28B polymorphisms.

Baseline demographic, clinic, laboratory and histological features as well as IL28B rs12979860 and rs8099917 polymorphisms frequency of 32 PBC patients are shown in Table 3. In comparison to non-CC rs12979860 (n = 16), CC rs12979860 genotype (n = 16) was associated with early histological stage (93.8% vs. 62.5%, P = 0.03) and higher mean ALT levels (71 ± 64 vs. 50 ± 25, P = 0.05) at univariate analysis. No statistically significant differences were found comparing non-TT rs8099917 patients with TT rs8099917 ones.

Table 3. Univariate Analysis on Demographic, Laboratory, Clinical and Histological Characteristics at Onset Between PBC Patients With CC rs12979860 (n = 16) vs. non-CC rs12979860 (n = 16) Interleukin-28B Polymorphism
VariableCC rs12979860 (n = 16)Non-CC rs12979860 (n = 16)P
Age - years, mean ± SD54 ± 1052 ± 14n.s.
Total Bilirubin (mg/dL), mean ± SD0.6 ± 0.240.53 ± 0.29n.s.
Alanine aminotransferase (IU/L), mean ± SD71 ± 6450 ± 250.05
γ-Glutamyl Transpeptidase (IU/L), mean ± SD188 ± 125199 ± 173n.s.
Alkaline Phosphatase (IU/L), mean ± SD281 ± 222295 ± 171n.s.
Platelets (x103/mmc), mean ± SD266 ± 64233 ± 95n.s.
Symptomatics, No. (%)6 (37.5)10 (62.5)n.s
Extrahepatic autoimmune diseases, No. (%)8 (50)8 (50)n.s
Liver Histology, No. (%)0.03
Early (I - II)15 (93.8)10 (62.5)
Advanced (III - IV)1 (6.7)6 (37.5)
4.3. Subgroup Analysis for HLA Class II Typing

HLA-DRB1 allele frequencies of 31 PBC patients are reported in Table 4. Compared to healthy controls (n = 237), we found a higher frequency of HLA-DRB1 * 07 (39.2% vs. 11.4%, RR 5.03) and HLA-DRB1 * 08 (10.7% vs. 0, RR n.c.).

Table 4. Typing of HLA Class II Alleles of Major Histocompatibility Complex (MHC) in PBC Patients Compared to a Control Group of Healthy Subjectsa
DRB1 AllelesPBC (n = 28)Controls (n = 237)R. R.PP*
HLA DRB1*0711 (39.2)27 (11.4)5.030.000070.0008
HLA DRB1*083 (10.7)0n.s.0.000040.0005
HLA DRB1*145 (17.8)16 (6.7)3.00.02n.s.
HLA DRB1*114 (14.2)87 (36.7)0.280.04n.s.
HLA DRB1*136 (21.4)24 (10.1)n.s.n.s.
HLA DRB1*152 (7.1)63 (26.5)0.210.02n.s.

aValues are expressed as No. (%).

4.4. Analysis of Follow-up

Amongst the 73 patients in follow-up (mean duration 61 months), three died (two because of cardiovascular disease and one because of end-stage liver disease) and one underwent liver transplantation. Overall, 16 (21.9%) patients had progression of a disease (Table 5).

Table 5. Events Leading to Disease Progression in 16 out of 73 PBC Patient (Mean Follow-Up 61 Months)a
Event (Disease Progression: n = 16)N = 73
US signs of portal hypertension20 (27.4)
Esophageal varices11 (15.1)
Ascites3 (4.1)
Hepatic encephalopathy2 (2.7)
Jaundice (bilirubin >5 mg/dL)2 (2.7)
Liver transplantation1 (1.4)
Death3 (4.1)
Hepatocellular carcinoma0

aValues are expressed as No. (%).

The rate of progression of disease was equal amongst patients with AMA positivity or AMA negativity. Furthermore, 81.3% of patients with disease progression had medium/intense itching during follow-up and amongst all patients with medium or intense itching, 48.1% had disease progression as compared to 6.5% without pruritus. Five years after diagnosis, 13% of patients with initial histological stage and 49% of patients with advanced histological stage showed sonographic signs of portal hypertension, whereas 8% of patients with initial histological stage and 27% with advanced histological stage developed esophageal varices (Figure 2). Notably, no patient developed hepatocellular carcinoma.

Event-Free Survival (Portal Hypertension) in PBC Patients with Early Stage (Solid Line) and Advanced Stage (Broken Line); P = 0.026 by Log-Rank Test
Figure 2. Event-Free Survival (Portal Hypertension) in PBC Patients with Early Stage (Solid Line) and Advanced Stage (Broken Line); P = 0.026 by Log-Rank Test

The only independent risk factors associated with disease progression for the multivariate analysis was, the presence of extrahepatic autoimmune disease (P = 0.049, RR 2.96), pruritus for more than one year (P = 0.008, RR 3.84) and advanced histological stage (P < 0.001, RR 8.31) (Table 6).

Table 6. Multivariate Analysis of Risk Factors Associated With Disease Progression in 73 Patients with Primary Biliary Cirrhosis by Logistic Regression Analysis
CovariatesβS.E.O.R. (95% CI)P
Extrahepatic autoimmune diseases1.0860.5532.96 (1.007 - 8.711)0.049
Persistence of pruritus > 1 year1.3460.5093.84 (1.424 - 10.379)0.008
Advanced (III - IV) histological stage2.1170.5548.31 (2.823 - 24.471)0.0001

5. Discussion

Primary biliary cirrhosis, as well as other autoimmune diseases are more common in Caucasian populations. Nevertheless, few European studies exist on epidemiology and disease course of PBC and most of them are derived from Northern European cohorts (3). In addition, natural history of PBC is incompletely characterized in patients of the Mediterranean area whose genetic background and risk factors might differ from those of Northern Europeans.

Our patients showed demographic, clinical and biochemical features at onset, which was very similar to those described in other population-based cohorts. In particular, patients with AMA-negative PBC have a comparable presentation and progression of the disease compared to AMA-positive subjects, as already stated by several evidences (1). A more severe cytolytic pattern was observed at onset in younger patients compared with older ones, a trend that was already emphasized by Muratori et al. (31). Interestingly, the most common symptom in our cohort was pruritus, which was complained in a sporadic or constant way in about half of the patients at diagnosis, while fatigue was less reported (16% of patients). These two symptoms have been related to an impairment of the quality of life with potential serious repercussions (32, 33). In a study by Prince et al. (34), the prevalence of fatigue at diagnosis was similar to that reported in our cohort (21%) but itching was present at diagnosis in only 18.9% of patients, a smaller proportion compared with our findings.

The rate of progression of PBC is extremely variable (1). In our cohort, presence of pruritus for more than one year, an advanced histological stage at diagnosis and the presence of extrahepatic autoimmune disease were found to be independently associated with disease progression. With regards to the first, several authors already reported that symptomatic patients at diagnosis have a shorter survival rate compared with asymptomatic subjects (35, 36). It is interesting that among all the symptoms only itching was associated with progression of the disease. The presence of an advanced histological stage is recognizably associated with a greater rate of progression, due to the fact that it is representative of a disease, which was already advanced at diagnosis in most of the cases. Lastly, the association of other autoimmune diseases, with a less favourable prognosis, had already been suggested by several lines of evidence (36). Nonetheless, the association of PBC with other autoimmune diseases further confirms the immune pathogenesis of the disease. In our cohort, 33 (40.7%) out of 81 patients showed an association with extrahepatic autoimmune diseases. Amongst these, the most frequent one was Sjogren’s syndrome (27.2%). This finding confirms its high prevalence in patients with PBC, as reported by recent studies (37, 38).

Interestingly, the median value of the total cholesterol was quite high in comparison to that of the healthy population. A recent systematic review (39) showed that cholesterol levels are increased in about 50% of patients with PBC. Essentially, 75% of the patients in our series had a total cholesterol value greater than the normal values (> 200 mg/dL). Even if the risk of mortality from cardiovascular disease is not increased in patients with PBC, despite the presence of hypercholesterolemia (40), we reported two deaths for cardiovascular events during follow-up.

Typing of HLA class II alleles of MHC in a subgroup of patients (n = 31) and its comparison with a control group of healthy subjects (n = 237) showed a higher frequency of HLA-DRB1 * 07 and HLA-DRB1 * 08 in PBC. In contrast to other series from Northern Europe (5), we also reported a higher prevalence of a DRB1 * 08 allele of HLA class II, respect to DRB1 * 07. This difference may reflect a different genetic background of patients from the Mediterranean area as compared to those of Northern Europe.

One of the most interesting findings arising from our cohort lies in the statistically significant association between CC IL28B rs12979860 genotype, early histological stage and higher mean ALT values. To our knowledge, this is the first study assessing the potential association between IL28B polymorphisms and the severity of liver damage in PBC patients. Our original result is consistent with the identification of an independent association between the presence of IL28B CC homozygosis, the genotype associated with a good response to antiviral therapy in patients with chronic hepatitis C (41), and the severity of inflammation at early stages in patients with PBC. In this line, growing evidences demonstrated that IL28B rs12979860 polymorphism strongly affects the histological severity of chronic liver diseases, in terms of both necroinflammation and fibrosis progression, independently of the underlying etiology (24, 41-43). By contrast, we did not find any association with IL28B rs12979917 polymorphism. However, it should be noted that our data is not consistent enough to evaluate whether patients with PBC have a higher prevalence of IL28B rs12979860 CC genotype compared to the Mediterranean general population, due to the lack of data in this setting. Of note, we can only observe that the frequency (about 50%) of IL28B rs12979860 CC genotype in our PBC cohort is higher compared with that reported (about 30%) in Sicilian patients with chronic hepatitis C (44) and similar to that observed (46%) in a homogeneous cohort of 301 Sicilian patients with thalassemia major (45).

Evidently, the main and biggest limitation of our study lies in the small simple size of our cohort and the fact that the genetic analysis was performed on a fraction of patients only. In addition, data regarding the progression of the disease is mainly limited to development of portal hypertension, an aspect likely due to the small number of reported events. However, although all of the above data needs further validation in larger studies, they might identify a subgroup of PBC patients at a higher risk of disease severity and progression deserving a more rigorous follow-up. Furthermore, these high-risk patients may be the ideal candidates who could benefit from possible future experimental treatments of chronic liver diseases focused on liver regeneration, including the use of endogenous hepatocytes, fetal hepatic stem cells, bone marrow-derived stem cells and embryonic stem cells and induced pluripotent stem cells (46).

In conclusion, our prospective cohort study provides further insights in the natural history and overall genetic background of Mediterranean patients with PBC. At disease onset, a more severe biochemical activity was observed in younger patients, while the presence of rs12979860 CC genotype was associated with a milder histological stage. Persistence of pruritus and presence of extrahepatic autoimmune liver disease were significantly associated with a poorer prognosis. Taken altogether, these findings might be useful to identify subgroups of PBC patients at different risks of disease severity and progression. However, larger studies are needed in this setting to elaborate novel follow-up protocols or treatment strategies for such patients.

Acknowledgements

Footnotes

References

  • 1. Poupon R. Primary biliary cirrhosis: a 2010 update. J Hepatol. 2010; 52(5) : 745 -58 [DOI][PubMed]
  • 2. Kim WR, Lindor KD, Locke G3, Therneau TM, Homburger HA, Batts KP, et al. Epidemiology and natural history of primary biliary cirrhosis in a US community. Gastroenterology. 2000; 119(6) : 1631 -6 [PubMed]
  • 3. Prince MI, James OF. The epidemiology of primary biliary cirrhosis. Clin Liver Dis. 2003; 7(4) : 795 -819 [PubMed]
  • 4. Selmi C, Mayo MJ, Bach N, Ishibashi H, Invernizzi P, Gish RG, et al. Primary biliary cirrhosis in monozygotic and dizygotic twins: genetics, epigenetics, and environment. Gastroenterology. 2004; 127(2) : 485 -92 [PubMed]
  • 5. Zhang L, Weetman AP, Bassendine M, Oliveira DB. Major histocompatibility complex class-II alleles in primary biliary cirrhosis. Scand J Immunol. 1994; 39(1) : 104 -6 [PubMed]
  • 6. Invernizzi P, Battezzati PM, Crosignani A, Perego F, Poli F, Morabito A, et al. Peculiar HLA polymorphisms in Italian patients with primary biliary cirrhosis. J Hepatol. 2003; 38(4) : 401 -6 [PubMed]
  • 7. Invernizzi P, Selmi C, Poli F, Frison S, Floreani A, Alvaro D, et al. Human leukocyte antigen polymorphisms in Italian primary biliary cirrhosis: a multicenter study of 664 patients and 1992 healthy controls. Hepatology. 2008; 48(6) : 1906 -12 [DOI][PubMed]
  • 8. Liu X, Invernizzi P, Lu Y, Kosoy R, Lu Y, Bianchi I, et al. Genome-wide meta-analyses identify three loci associated with primary biliary cirrhosis. Nat Genet. 2010; 42(8) : 658 -60 [DOI][PubMed]
  • 9. Juran BD, Lazaridis KN. Genetics and genomics of primary biliary cirrhosis. Clin Liver Dis. 2008; 12(2) : 349 -65 [DOI][PubMed]
  • 10. Mells GF, Floyd JA, Morley KI, Cordell HJ, Franklin CS, Shin SY, et al. Genome-wide association study identifies 12 new susceptibility loci for primary biliary cirrhosis. Nat Genet. 2011; 43(4) : 329 -32 [DOI][PubMed]
  • 11. Poupon R, Ping C, Chretien Y, Corpechot C, Chazouilleres O, Simon T, et al. Genetic factors of susceptibility and of severity in primary biliary cirrhosis. J Hepatol. 2008; 49(6) : 1038 -45 [DOI][PubMed]
  • 12. Hirschfield GM, Liu X, Xu C, Lu Y, Xie G, Lu Y, et al. Primary biliary cirrhosis associated with HLA, IL12A, and IL12RB2 variants. N Engl J Med. 2009; 360(24) : 2544 -55 [DOI][PubMed]
  • 13. Gershwin ME, Selmi C, Worman HJ, Gold EB, Watnik M, Utts J, et al. Risk factors and comorbidities in primary biliary cirrhosis: a controlled interview-based study of 1032 patients. Hepatology. 2005; 42(5) : 1194 -202 [DOI][PubMed]
  • 14. Ala A, Stanca CM, Bu-Ghanim M, Ahmado I, Branch AD, Schiano TD, et al. Increased prevalence of primary biliary cirrhosis near Superfund toxic waste sites. Hepatology. 2006; 43(3) : 525 -31 [DOI][PubMed]
  • 15. Leung PS, Park O, Tsuneyama K, Kurth MJ, Lam KS, Ansari AA, et al. Induction of primary biliary cirrhosis in guinea pigs following chemical xenobiotic immunization. J Immunol. 2007; 179(4) : 2651 -7 [PubMed]
  • 16. Selmi C, Gershwin ME. The role of environmental factors in primary biliary cirrhosis. Trends Immunol. 2009; 30(8) : 415 -20 [DOI][PubMed]
  • 17. Metcalf JV, Bhopal RS, Gray J, Howel D, James OF. Incidence and prevalence of primary biliary cirrhosis in the city of Newcastle upon Tyne, England. Int J Epidemiol. 1997; 26(4) : 830 -6 [PubMed]
  • 18. James OF, Bhopal R, Howel D, Gray J, Burt AD, Metcalf JV. Primary biliary cirrhosis once rare, now common in the United Kingdom? Hepatology. 1999; 30(2) : 390 -4 [DOI][PubMed]
  • 19. Delgado J, Sperber AD, Novack V, Delgado B, Edelman L, Gaspar N, et al. The epidemiology of primary biliary cirrhosis in southern Israel. Isr Med Assoc J. 2005; 7(11) : 717 -21 [PubMed]
  • 20. Pla X, Vergara M, Gil M, Dalmau B, Cistero B, Bella RM, et al. Incidence, prevalence and clinical course of primary biliary cirrhosis in a Spanish community. Eur J Gastroenterol Hepatol. 2007; 19(10) : 859 -64 [DOI][PubMed]
  • 21. Myers RP, Shaheen AA, Fong A, Burak KW, Wan A, Swain MG, et al. Epidemiology and natural history of primary biliary cirrhosis in a Canadian health region: a population-based study. Hepatology. 2009; 50(6) : 1884 -92 [DOI][PubMed]
  • 22. Piazza A, Olivetti E, Griffo RM, Rendine S, Amoroso A, Barbanti M, et al. The distribution of HLA antigens in Italy. Gene Geogr. 1989; 3(2-3) : 141 -64 [PubMed]
  • 23. Ge D, Fellay J, Thompson AJ, Simon JS, Shianna KV, Urban TJ, et al. Genetic variation in IL28B predicts hepatitis C treatment-induced viral clearance. Nature. 2009; 461(7262) : 399 -401 [DOI][PubMed]
  • 24. Petta S, Grimaudo S, Camma C, Cabibi D, Di Marco V, Licata G, et al. IL28B and PNPLA3 polymorphisms affect histological liver damage in patients with non-alcoholic fatty liver disease. J Hepatol. 2012; 56(6) : 1356 -62 [DOI][PubMed]
  • 25. Kempuraj D, Donelan J, Frydas S, Iezzi T, Conti F, Boucher W, et al. Interleukin-28 and 29 (IL-28 and IL-29): new cytokines with anti-viral activities. Int J Immunopathol Pharmacol. 2004; 17(2) : 103 -6 [PubMed]
  • 26. Morrow MP, Pankhong P, Laddy DJ, Schoenly KA, Yan J, Cisper N, et al. Comparative ability of IL-12 and IL-28B to regulate Treg populations and enhance adaptive cellular immunity. Blood. 2009; 113(23) : 5868 -77 [DOI][PubMed]
  • 27. Lindor KD, Gershwin ME, Poupon R, Kaplan M, Bergasa NV, Heathcote EJ, et al. Primary biliary cirrhosis. Hepatology. 2009; 50(1) : 291 -308 [DOI][PubMed]
  • 28. O'Shea RS, Dasarathy S, McCullough AJ, Practice Guideline Committee of the American Association for the Study of Liver D, Practice Parameters Committee of the American College of G. Alcoholic liver disease. Hepatology. 2010; 51(1) : 307 -28 [DOI][PubMed]
  • 29. de Franchis R, Baveno V. Revising consensus in portal hypertension: report of the Baveno V consensus workshop on methodology of diagnosis and therapy in portal hypertension. J Hepatol. 2010; 53(4) : 762 -8 [DOI][PubMed]
  • 30. European Association for the Study of the L. EASL Clinical Practice Guidelines: management of cholestatic liver diseases. J Hepatol. 2009; 51(2) : 237 -67 [DOI][PubMed]
  • 31. Muratori P, Granito A, Pappas G, Muratori L, Lenzi M, Bianchi FB. Clinical and serological profile of primary biliary cirrhosis in young and elderly patients. QJM. 2008; 101(6) : 505 -6 [DOI][PubMed]
  • 32. Selmi C, Gershwin ME, Lindor KD, Worman HJ, Gold EB, Watnik M, et al. Quality of life and everyday activities in patients with primary biliary cirrhosis. Hepatology. 2007; 46(6) : 1836 -43 [DOI][PubMed]
  • 33. Newton JL, Gibson GJ, Tomlinson M, Wilton K, Jones D. Fatigue in primary biliary cirrhosis is associated with excessive daytime somnolence. Hepatology. 2006; 44(1) : 91 -8 [DOI][PubMed]
  • 34. Prince MI, Chetwynd A, Craig WL, Metcalf JV, James OF. Asymptomatic primary biliary cirrhosis: clinical features, prognosis, and symptom progression in a large population based cohort. Gut. 2004; 53(6) : 865 -70 [PubMed]
  • 35. Balasubramaniam K, Grambsch PM, Wiesner RH, Lindor KD, Dickson ER. Diminished survival in asymptomatic primary biliary cirrhosis. A prospective study. Gastroenterology. 1990; 98(6) : 1567 -71 [PubMed]
  • 36. Mahl TC, Shockcor W, Boyer JL. Primary biliary cirrhosis: survival of a large cohort of symptomatic and asymptomatic patients followed for 24 years. J Hepatol. 1994; 20(6) : 707 -13 [PubMed]
  • 37. Liu B, Zhang FC, Zhang ZL, Zhang W, Gao LX. Interstitial lung disease and Sjogren's syndrome in primary biliary cirrhosis: a causal or casual association? Clin Rheumatol. 2008; 27(10) : 1299 -306 [DOI][PubMed]
  • 38. Hatzis GS, Fragoulis GE, Karatzaferis A, Delladetsima I, Barbatis C, Moutsopoulos HM. Prevalence and longterm course of primary biliary cirrhosis in primary Sjogren's syndrome. J Rheumatol. 2008; 35(10) : 2012 -6 [PubMed]
  • 39. Sorokin A, Brown JL, Thompson PD. Primary biliary cirrhosis, hyperlipidemia, and atherosclerotic risk: a systematic review. Atherosclerosis. 2007; 194(2) : 293 -9 [DOI][PubMed]
  • 40. Cash WJ, McCance DR, Young IS, McEneny J, Cadden IS, McDougall NI, et al. Primary biliary cirrhosis is associated with oxidative stress and endothelial dysfunction but not increased cardiovascular risk. Hepatol Res. 2010; 40(11) : 1098 -106 [DOI][PubMed]
  • 41. Thompson AJ, Muir AJ, Sulkowski MS, Ge D, Fellay J, Shianna KV, et al. Interleukin-28B polymorphism improves viral kinetics and is the strongest pretreatment predictor of sustained virologic response in genotype 1 hepatitis C virus. Gastroenterology. 2010; 139(1) : 120 -9 e18 [DOI][PubMed]
  • 42. Bochud PY, Bibert S, Kutalik Z, Patin E, Guergnon J, Nalpas B, et al. IL28B alleles associated with poor hepatitis C virus (HCV) clearance protect against inflammation and fibrosis in patients infected with non-1 HCV genotypes. Hepatology. 2012; 55(2) : 384 -94 [DOI][PubMed]
  • 43. Eslam M, Hashem AM, Leung R, Romero-Gomez M, Berg T, Dore GJ, et al. Interferon-lambda rs12979860 genotype and liver fibrosis in viral and non-viral chronic liver disease. Nat Commun. 2015; 6 : 6422 [DOI][PubMed]
  • 44. Petta S, Ferraro D, Camma C, Cabibi D, Di Cristina A, Di Marco V, et al. Vitamin D levels and IL28B polymorphisms are related to rapid virological response to standard of care in genotype 1 chronic hepatitis C. Antivir Ther. 2012; 17(5) : 823 -31 [DOI][PubMed]
  • 45. Di Marco V, Bronte F, Calvaruso V, Capra M, Borsellino Z, Maggio A, et al. IL28B polymorphisms influence stage of fibrosis and spontaneous or interferon-induced viral clearance in thalassemia patients with hepatitis C virus infection. Haematologica. 2012; 97(5) : 679 -86 [DOI][PubMed]
  • 46. Cieslar-Pobuda A, Wiechec E. Research on liver regeneration as an answer to the shortage of donors for liver transplantation. Hepatol Res. 2014; 44(9) : 944 -6 [DOI][PubMed]
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