Prevalence of primary biliary cirrhosis in adults referring hospital for annual health check-up in Southern China
© Liu et al; licensee BioMed Central Ltd. 2010
Received: 24 June 2010
Accepted: 3 September 2010
Published: 3 September 2010
Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterized by the presence of anti-mitocondrial autoantibodies (AMA) which has an essential role also for diagnosis. In addition, also some anti-nuclear antibodies (ANA) have been shown to be highly specific PBC. The purpose of this study was to assess the prevalence of PBC among the adults referring hospital for annual health check-up in Southern China by screening sera for PBC-specific autoantibodies.
AMA and ANA were screened in 8,126 adults (mean age 44 ± 15 years, 48% females) by indirect immunofluorenscence (IIF). Positive sera were tested by ELISA/immunoblotting for AMA-M2, anti-sp100 and anti-gp210. A diagnosis of PBC was re-assessed six months after the initial testing.
Out of 8,126 individuals 35 were positive for AMA and 79 positive for ANA. Nineteen, 4, and 3 of the subjects positive for AMA and/or ANA showed reactivity for AMA-M2, anti-sp100 or gp210, respectively, further tested with ELISA/immunoblotting. Fourteen in the 39 individuals positive for AMA at IIF, AMA-M2, anti-gp210, or anti-sp100 had abnormal cholestatic liver functional indices. One definite and 3 probable PBC diagnosis could be made in 4 cases including 3 females and 1 male after half a year.
We found a point prevalence rate of PBC among Southern Chinese adults attending for yearly health check-up of 492 cases per million (95% CI, 128 to 1,093) and 1,558 cases per million (95% CI, 294 to 3,815) for women over 40, a finding similar to prevalence reported in other geographical areas.
Primary biliary cirrhosis (PBC) is an autoimmune liver disease leading to progressive destruction of small intrahepatic bile ducts, development of cirrhosis, and liver failure . PBC affects predominantly women over middle-age . It has been reported that PBC is more prevalent in some geographic areas such as Northern Europe and Northern America but much less common in Eastern Asia, Africa, and Australia [3–6]. However, it is worth noting that a rising frequency in many areas may be due to a more widespread awareness of this disease among physicians. Case series of Chinese patients with PBC have been reported from Taiwan, Hong Kong, Singapore and, more recently, also from Mainland China [6–11], with a number of Chinese patients with PBC apparently to be increasing in recent years. However, no epidemiological data have accompanied these reports.
PBC is serologically characterized by the presence of anti-mitochondrial antibodies (AMA), which are reactive mainly with E2 subunits of mitochondrial multi-enzyme complexes, the 2-oxo-acid dehydrogenase complexes comprising pyruvate dehydrogenase complex (PDC), branched chain 2-oxo-acid dehydrogenase complex (BCOADC) and 2-oxo-glutarate dehydrogenase complex (OGDC) . These specific AMA are called AMA-M2 and are detectable in up to 95% of the patients [13, 14]. In addition to AMA, two distinct anti-nuclear antibodies (ANA) patterns are detectable by indirect immunofluorescence (IIF), the multiple nuclear dot (MND) and rim-like (RL) patterns, for which the reactants are sp100 and the glycoprotein gp210 respectively [15, 16].
The aim of this study was to investigate the prevalence of PBC among adults referring for annual health check-up by screening PBC-specific autoantibodies.
A total of 8,126 citizens of Guangzhou, Southern China, aged from 18 to 83 years, with a median age of 44 ± 15 years, were consecutively enrolled in the study. 4,248 (52%) were males (median age of 46 ± 15 years), 3,878 (48%) were females (median age 41 ± 14 years), and 1,926 (24%) were aged over 40 years. They underwent a yearly health check-up at the Liuhuaqiao Hospital from June to September 2006, including a physical examination, routine blood tests, abdominal ultrasonography, chest X ray, electrocardiogram, and serum markers of hepatitis B (HBsAg). The male to female ratio in the current study (1.1) reflects the general sex distribution in Guangzhou (1.0) investigated at the end of 2005 http://www.civic-exchange.org/eng/upload/files/200806_AirQualityPublicHealth.pdf.
This study was in compliance with the Helsinki Declaration http://www.wma.net/e/policy/b3.htm and was approved by the regional ethical committee of the Guangdong province, China. All subjects signed an informed consent to be enrolled and all data were dealt with in an anonymous way.
Screening of AMA and ANA
Detection of AMA-M2, anti-gp210 and anti-sp100
Sera positive for AMA and/or ANA by IIF were further tested for AMA-M2, anti-gp210 and anti-sp100. AMA-M2 in serum samples diluted 1:100 were determined using ELISA kits with wells coated with recombinant fusion protein containing the immunodominant epitopes of human PDC-E2, BCOADC-E2 and OGDC-E2 (Fuchunzhongnan Biotech, Shanghai, China). Anti-sp100 and anti-gp210 were detected at a dilution of 1:100 by an immunoblotting assay with recombinant sp100 and gp210 proteins (IMTEC, Berlin, Germany).
The routine diagnostic laboratory indices included liver function such as serum total protein, albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol, triglyceride, and immunoassays for hepatitis B virus (HBV) infection (HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc). Sera positive for PBC-specific autoantibodies were additionally tested for antibodies against other hepatitis viruses (HAV, HCV and HEV), serum immunoglobulins (Ig), total bilirubin (TBil), alkaline phosphatase (AP), and gamma-glutamyl transpeptidase (γ-GT).
Diagnosis of PBC
All subjects positive for at least one of the PBC-specific antibodies and with abnormal results for liver function tests were advised to visit hepatologists for further checks, and the laboratory indices were retested after six months. A diagnosis of PBC was made according to criteria recommended by the European Association for the study of the Liver (EASL) : unexplained elevation of ALP and presence of AMA (≥ 1:40) and/or AMA-M2.
SPSS13.0 software was applied to calculate 95% confidence intervals (CI) for frequencies of autoantibodies and the point prevalence rate of PBC. χ2 test was used to compare categorical variables. Two-tailed P values of less than 0.05 were considered to be statistically significant.
AMA and ANA frequencies
Indirect immunofluorescence patterns of 79 subjects with anti-nuclear antibodies (ANA) on HEp-2 cells.
Multiple nuclear dots
AMA-M2, anti-sp100 and anti-gp210 frequencies
Indirect immunofluorescence (IIF) patterns according to specific immunoreactivities (AMA-M2, anti-sp100 and anti-gp210) in the 104 sera positive for AMA and/or ANA.
Clinical characteristics of subjects with PBC-specific antibodies
There was 17 individuals AMA positive at IIF in whom none of M2, anti-sp100 or anti-gp210 was detected. Overall, 39 of the 8,126 sera (0.48%, 95% CI: 0.34%-0.64%) were tested positive for AMA at IIF, AMA-M2, anti-gp210, or anti-sp100, that is all the known PBC-specific serum immunoreactivities [2, 15]. Fourteen of these 39 individuals (8 of 14 were females) had at least one abnormal test of liver function. None showed signs of current infection with a hepatitis virus. All 14 subjects with abnormal tests of liver function were contacted for further clinical evaluation, but only one, a 60 year old woman with fatigue and elevated serum immunoglobulins, total bilirubin, AP, and γ-GT, underwent ERCP and liver biopsy. ERCP did not disclose biliary tract abnormalities, and liver biopsy showed periportal hepatitis and bile duct proliferation indicative of a histological stage II PBC . Another three cases without any related clinical signs, 2 females and one male aged 41, 64, 47 respectively, maintained abnormal liver functional indices after six months and also fulfilled the diagnostic criteria of PBC proposed by EASL.
Discussion and conclusions
The first patient to be recorded with PBC in Mainland China was reported in 1958 and only an additional 48 cases were later on reported from 1980 to 2000 . Although there have been an increasing number of reported diagnoses, PBC is still thought to be very rare in Asian populations. Moreover, there is a lack of solid epidemiological information relevant to this issue . Therefore, we took advantage of annual health check-up data and designed a study to estimate the prevalence of PBC in the adult population of a defined area of Southern China by screening for all the known PBC-specific serum autoantibodies .
Four individuals were diagnosed as PBC, 3 females and 1 male, among 8,126 adults (over age 18) resident in the Southern Chinese city of Guangzhou who attended for an annual health check-up; the rate of hepatitis B virus in this population was 8.1%. The point prevalence rate of PBC was 492 cases per million (95% CI: 128 to 1,093), among the highest reported in other geographical regions [5, 22–26]. By considering the risk of PBC for women over 40 years, i.e. a "high risk group", a prevalence of 1,558 cases per million (95% CI: 294 to 3,815) was observed.
Unfortunately, we could not confirm the diagnosis of PBC by means of liver biopsy in all the subjects with cholestasis and the presence of PBC-specific autoantibodies. But the serum autoantibodies we determined are highly specific for PBC , which allowed us to screen adults in a relatively natural distribution of the general population, thus providing a fair estimate of the real prevalence of PBC in Mainland China.
The prevalence of PBC found in our study is similar to that reported in an early evaluation from Italy, in which diagnosis was based on ultrasound scanning, elevated AP and presence of AMA , but much lower than the estimated prevalence of PBC for middle-aged women in Japan . However, it is to note that in this latter study the screening comprised only increase in serum γ-GT levels among 4,048 asymptomatic women attending for an annual health check-up. It is evident that prevalence obtained from laboratory parameters are higher than prevalence derived from studies using a physician survey and review of hospital records [29–33]. The reason may be that laboratory methods can identify asymptomatic cases that would be overlooked by case-finding; for instance, the four PBC patients identified in our study including the patient who already developed symptoms had never encountered a hepatologist. Overall, the variation in PBC prevalence among different studies may be attributable to differences in study populations and periods and the methods of case ascertainment .
Jiang and colleagues identified 3 (0.06%) PBC cases from 5,011 adults from eastern China . Lately, 38 PBC cases were reported in Singapore, a small Asian city-state with population of 4 million and ethnic distribution of 76% Chinese . Based on the current and early findings, the prevalence of PBC in Asia, especially in Mainland China, is not as rare as might be expected, being comparable with high prevalence sites in Northern Europe and the United States of America .
In areas like Mainland China where there is still lack of registry system for healthcare and PBC is not well recognized by clinical doctors the need of data on disease prevalence and incidence is crucial. We are now reporting data from a screening of PBC starting from combination of PBC specific autoantibodies in adults at random with age and sex in a relatively natural distribution. We are aware that our cross-sectional observational study has a number of limitations, also because allowed us to identify only a small absolute number of cases. Theoretically, a population-based study is the best study design to define the prevalence of a disease, and efforts have to be done to accomplish such studies in the near future.
Intriguingly, the current study confirms the observation of a nearly equal male to female ratio found in large-scale screening studies, as we have recently highlighted . On the contrary, studies based on case-finding methods reported a strong female preponderance, possibly because they account only for already diagnosed cases . Although the reasons for this discrepancies remain unknown, clearly rely to the different study designed used.
In summary, our data suggest that PBC is not as rare as expected before with the point prevalence rate of PBC in Chinese which is quite comparable to that reported in other geographical areas.
- Kaplan MM, Gershwin ME: Primary biliary cirrhosis. N Engl J Med. 2005, 353 (12): 1261-1273. 10.1056/NEJMra043898.View ArticlePubMedGoogle Scholar
- Invernizzi P, Selmi C, Ranftler C, Podda M, Wesierska-Gadek J: Antinuclear antibodies in primary biliary cirrhosis. Semin Liver Dis. 2005, 25 (3): 298-310. 10.1055/s-2005-916321.View ArticlePubMedGoogle Scholar
- Farrell GC: Primary biliary cirrhosis in Asians: less common than in Europeans, but just as depressing. J Gastroenterol Hepatol. 2008, 23 (4): 508-511. 10.1111/j.1440-1746.2008.05379.x.View ArticlePubMedGoogle Scholar
- Gross RG, Odin JA: Recent advances in the epidemiology of primary biliary cirrhosis. Clin Liver Dis. 2008, 12 (2): 289-303. 10.1016/j.cld.2008.02.001. viiiView ArticlePubMedGoogle Scholar
- Invernizzi P: Geoepidemiology of autoimmune liver diseases. J Autoimmun. 34 (3): J300-306. 10.1016/j.jaut.2009.12.002.
- Liu HY, Deng AM, Zhang J, Zhou Y, Yao DK, Tu XQ, Fan LY, Zhong RQ: Correlation of Chlamydia pneumoniae infection with primary biliary cirrhosis. World J Gastroenterol. 2005, 11 (26): 4108-4110.View ArticlePubMedPubMed CentralGoogle Scholar
- Liang Y, Yang Z, Li C, Zhu Y, Zhang L, Zhong R: Characterisation of TNF-related apoptosis-inducing ligand in peripheral blood in patients with primary biliary cirrhosis. Clin Exp Med. 2008, 8 (1): 1-7. 10.1007/s10238-008-0149-z.View ArticlePubMedGoogle Scholar
- Shen M, Zhang F, Zhang X: Primary biliary cirrhosis complicated with interstitial lung disease: a prospective study in 178 patients. J Clin Gastroenterol. 2009, 43 (7): 676-679. 10.1097/MCG.0b013e31818aa11e.View ArticlePubMedGoogle Scholar
- Su CW, Hung HH, Huo TI, Huang YH, Li CP, Lin HC, Lee PC, Lee SD, Wu JC: Natural history and prognostic factors of primary biliary cirrhosis in Taiwan: a follow-up study up to 18 years. Liver Int. 2008, 28 (9): 1305-1313. 10.1111/j.1478-3231.2008.01715.x.View ArticlePubMedGoogle Scholar
- Wong GL, Law FM, Wong VW, Hui AY, Chan FK, Sung JJ, Chan HL: Health-related quality of life in Chinese patients with primary biliary cirrhosis. J Gastroenterol Hepatol. 2008, 23 (4): 592-598. 10.1111/j.1440-1746.2007.05092.x.View ArticlePubMedGoogle Scholar
- Wong RK, Lim SG, Wee A, Chan YH, Aung MO, Wai CT: Primary biliary cirrhosis in Singapore: evaluation of demography, prognostic factors and natural course in a multi-ethnic population. J Gastroenterol Hepatol. 2008, 23 (4): 599-605. 10.1111/j.1440-1746.2007.05058.x.View ArticlePubMedGoogle Scholar
- Moteki S, Leung PS, Coppel RL, Dickson ER, Kaplan MM, Munoz S, Gershwin ME: Use of a designer triple expression hybrid clone for three different lipoyl domain for the detection of antimitochondrial autoantibodies. Hepatology. 1996, 24 (1): 97-103. 10.1002/hep.510240117.View ArticlePubMedGoogle Scholar
- Gershwin ME, Coppel RL, Bearer E, Peterson MG, Sturgess A, Mackay IR: Molecular cloning of the liver-specific rat F antigen. J Immunol. 1987, 139 (11): 3828-3833.PubMedGoogle Scholar
- Oertelt S, Rieger R, Selmi C, Invernizzi P, Ansari AA, Coppel RL, Podda M, Leung PS, Gershwin ME: A sensitive bead assay for antimitochondrial antibodies: Chipping away at AMA-negative primary biliary cirrhosis. Hepatology. 2007, 45 (3): 659-665. 10.1002/hep.21583.View ArticlePubMedGoogle Scholar
- Invernizzi P, Lleo A, Podda M: Interpreting serological tests in diagnosing autoimmune liver diseases. Semin Liver Dis. 2007, 27 (2): 161-172. 10.1055/s-2007-979469.View ArticlePubMedGoogle Scholar
- Invernizzi P, Pasini S, Selmi C, Gershwin ME, Podda M: Female predominance and X chromosome defects in autoimmune diseases. J Autoimmun. 2009, 33 (1): 12-16. 10.1016/j.jaut.2009.03.005.View ArticlePubMedGoogle Scholar
- Vergani D, Alvarez F, Bianchi FB, Cancado EL, Mackay IR, Manns MP, Nishioka M, Penner E: Liver autoimmune serology: a consensus statement from the committee for autoimmune serology of the International Autoimmune Hepatitis Group. J Hepatol. 2004, 41 (4): 677-683. 10.1016/j.jhep.2004.08.002.View ArticlePubMedGoogle Scholar
- Bogdanos DP, Invernizzi P, Mackay IR, Vergani D: Autoimmune liver serology: current diagnostic and clinical challenges. World J Gastroenterol. 2008, 14 (21): 3374-3387. 10.3748/wjg.14.3374.View ArticlePubMedPubMed CentralGoogle Scholar
- European Association For The Study Of The L: EASL Clinical Practice Guidelines: management of chronic hepatitis B. J Hepatol. 2009, 50 (2): 227-242. 10.1016/j.jhep.2008.10.001.View ArticleGoogle Scholar
- Ludwig J, Dickson ER, McDonald GS: Staging of chronic nonsuppurative destructive cholangitis (syndrome of primary biliary cirrhosis). Virchows Arch A Pathol Anat Histol. 1978, 379 (2): 103-112. 10.1007/BF00432479.View ArticlePubMedGoogle Scholar
- Yao G: Stress on clinical research of primary biliary cirrhosis. Zhonghua Gan Zang Bing Za Zhi. 2002, 10 (5): 325-PubMedGoogle Scholar
- Hurlburt KJ, McMahon BJ, Deubner H, Hsu-Trawinski B, Williams JL, Kowdley KV: Prevalence of autoimmune liver disease in Alaska Natives. Am J Gastroenterol. 2002, 97 (9): 2402-2407. 10.1111/j.1572-0241.2002.06019.x.View ArticlePubMedGoogle Scholar
- Kim WR, Lindor KD, Locke GR, Therneau TM, Homburger HA, Batts KP, Yawn BP, Petz JL, Melton LJ, Dickson ER: Epidemiology and natural history of primary biliary cirrhosis in a US community. Gastroenterology. 2000, 119 (6): 1631-1636. 10.1053/gast.2000.20197.View ArticlePubMedGoogle Scholar
- Myers RP, Shaheen AA, Fong A, Burak KW, Wan A, Swain MG, Hilsden RJ, Sutherland L, Quan H: Epidemiology and natural history of primary biliary cirrhosis in a Canadian health region: a population-based study. Hepatology. 2009, 50 (6): 1884-1892. 10.1002/hep.23210.View ArticlePubMedGoogle Scholar
- Pla X, Vergara M, Gil M, Dalmau B, Cistero B, Bella RM, Real J: Incidence, prevalence and clinical course of primary biliary cirrhosis in a Spanish community. Eur J Gastroenterol Hepatol. 2007, 19 (10): 859-864. 10.1097/MEG.0b013e328277594a.View ArticlePubMedGoogle Scholar
- Rautiainen H, Salomaa V, Niemela S, Karvonen AL, Nurmi H, Isoniemi H, Farkkila M: Prevalence and incidence of primary biliary cirrhosis are increasing in Finland. Scand J Gastroenterol. 2007, 42 (11): 1347-1353. 10.1080/00365520701396034.View ArticlePubMedGoogle Scholar
- Magrini A, Nicodemo S, Puoti C: Hospital prevalence of asymptomatic primary biliary cirrhosis: 4-year study based on analysis of 4468 consecutive in-patients. Liver. 1996, 16 (6): 377-379.View ArticlePubMedGoogle Scholar
- Sakugawa H, Nakasone H, Nakayoshi T, Yamashiro T, Maeshiro T, Kobashigawa K, Kinjo F, Saito A, Zukeran H, Nakanuma Y, Ohba K: Epidemiology of primary biliary cirrhosis among women with elevated gamma-glutamyl transpeptidase levels in Okinawa, Japan. Hepatol Res. 2003, 26 (4): 330-336. 10.1016/S1386-6346(03)00167-0.View ArticlePubMedGoogle Scholar
- Delgado J, Sperber AD, Novack V, Delgado B, Edelman L, Gaspar N, Krugliak P, Odes S, Jotkowitz AB, Faszczyk M, Fich A: The epidemiology of primary biliary cirrhosis in southern Israel. Isr Med Assoc J. 2005, 7 (11): 717-721.PubMedGoogle Scholar
- 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): 390-394. 10.1002/hep.510300213.View ArticlePubMedGoogle Scholar
- Sood S, Gow PJ, Christie JM, Angus PW: Epidemiology of primary biliary cirrhosis in Victoria, Australia: high prevalence in migrant populations. Gastroenterology. 2004, 127 (2): 470-475. 10.1053/j.gastro.2004.04.064.View ArticlePubMedGoogle Scholar
- Turchany JM, Uibo R, Kivik T, Van de Water J, Prindiville T, Coppel RL, Gershwin ME: A study of antimitochondrial antibodies in a random population in Estonia. Am J Gastroenterol. 1997, 92 (1): 124-126.PubMedGoogle Scholar
- Kisand KE, Metskula K, Kisand KV, Kivik T, Gershwin ME, Uibo R: The follow-up of asymptomatic persons with antibodies to pyruvate dehydrogenase in adult population samples. J Gastroenterol. 2001, 36 (4): 248-254. 10.1007/s005350170111.View ArticlePubMedGoogle Scholar
- Jiang XH, Zhong RQ, Fan XY, Hu Y, An F, Sun JW, Kong XT: Characterization of M2 antibodies in asymptomatic Chinese population. World J Gastroenterol. 2003, 9 (9): 2128-2131.View ArticlePubMedPubMed CentralGoogle Scholar
- Lleo A, Battezzati PM, Selmi C, Gershwin ME, Podda M: Is autoimmunity a matter of sex?. Autoimmun Rev. 2008, 7 (8): 626-630. 10.1016/j.autrev.2008.06.009.View ArticlePubMedGoogle Scholar
- The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-230X/10/100/prepub