Overcoming a “Probable” Diagnosis in Antimitochondrial Antibody Negative Primary Biliary Cirrhosis: Study of 100 Sera and Review of the Literature

Serum anti-mitochondrial antibodies (AMA) are the serological hallmark of primary biliary cirrhosis (PBC), yet up to 15% of PBC sera are AMA negative at routine indirect immunofluorescence (IIF) while being referred to as ??probable?? cases. The diagnostic role of PBC-specific antinuclear antibodies (ANA) remains to be determined. We will report herein data on the accuracy of new laboratory tools for AMA and PBC-specific ANA in a large series of PBC sera that were AMA-negative at IIF. We will also provide a discussion of the history and current status of AMA detection methods. We included IIF AMA-negative PBC sera (n?=?100) and sera from patients with other chronic liver diseases (n?=?104) that had been independently tested for IIF AMA and ANA; sera were blindly tested with an ELISA PBC screening test including two ANA (gp210, sp100) and a triple (pMIT3) AMA recombinant antigens. Among IIF AMA-negative sera, 43/100 (43%) manifested reactivity using the PBC screening test. The same test was positive for 6/104 (5.8%) control sera. IIF AMA-negative/PBC screen-positive sera reacted against pMIT3 (11/43), gp210 (8/43), Sp100 (17/43), both pMIT3 and gp210 (1/43), or both pMIT3 and Sp100 (6/43). Concordance rates between the ANA pattern on HEp-2 cells and specific Sp100 and gp210 ELISA results in AMA-negative subjects were 92% for nuclear dots and Sp100 and 99% for nuclear rim and gp210. Our data confirm the hypothesis that a substantial part of IIF AMA-negative (formerly coined ??probable??) PBC cases manifest disease-specific autoantibodies when tested using newly available tools and thus overcome the previously suggested diagnostic classification. As suggested by the recent literature, we are convinced that the proportion of AMA-negative PBC cases will be significantly minimized by the use of new laboratory methods and recombinant antigens.     

Occurrence and significance of IgG liver membrane autoantibodies (LMA) in chronic liver diseases of different aetiology

The prevalence of liver cell membrane antibodies (LMA) was evaluated in the sera of 124 untreated patients with various chronic liver diseases, in 17 acute hepatitis patients and in 40 normal controls by indirect immunofluorescence on rabbit hepatocytes, isolated by non-enzymatic method. The presence of LMA was compared with the presence of HBs Ag, anti-HBc and non-organ specific autoantibodies (anti-nuclear antibody, ANA; smooth muscle antibody, SMA; anti-mitochondrial antibody, AMA; liver-kidney microsomal antibody, LKM). LMA was found in 83% of autoimmune chronic active liver disease (CALD), in 47% of cryptogenic CALD and in 42% of primary biliary cirrhosis (PBC). LMA prevalence both in HBsAg positive and HBsAg negative/anti-HBc positive CALD was 11%, significantly lower than in the other three groups. In the cryptogenic group the prevalence of non-organ specific autoantibodies was significantly lower than LMA prevalence. The 35 LMA positive sera were titred to end point dilution. Autoimmune cases presented titres higher than those of all the other groups. Adsorption experiments showed that in autoimmune cases LMA fluorescence is not blocked by pre-incubation with liver antigens LSP and LP2, while a mild blocking effect was observed in some HBsAg positive cases or PBC sera. No cross-reaction with mitochondrial antigens was observed in PBC sera. LMA can still be considered a marker of autoimmune CALD only when present at high titre and without cross-reactivity with other liver antigens.     

Autoantigens in primary biliary cirrhosis

The automimmune liver disease primary biliary cirrhosis (PBC) is characterised by serum autoantibodies directed at mitochondrial and nuclear antigens (seen in most patients and a subset of patients, respectively). The antimitochondrial antibodies (AMA) characteristic of PBC are directed at members of the 2-oxoacid dehydrogenase components of multienzyme complexes; in particular, the E2 and E3 binding protein (E3BP) components of the pyruvate dehydrogenase complex (PDC). The presence of autoantibodies reactive with PDC-E2 and/or E3BP is strongly predictive of the presence of PBC. Therefore, the detection of these antibodies plays a very important role in the diagnosis of PBC. Originally demonstrated using immunofluorescence approaches, AMA can now be detected by the use of commercially available enzyme linked immunosorbent assays (ELISAs). Although the ELISA based approaches have advantages in terms of laboratory practicality, they are slightly less sensitive for the diagnosis of PBC than immunofluorescence (occasional patients with PBC show reactivity with PDC related antigens not present in the antigen preparations available for use with ELISA). Therefore, immunofluorescence should continue to be available as a complementary diagnostic test for use in occasional patients. In a subset of patients with PBC, autoantibodies are directed at increasingly well characterised nuclear antigens. Antinuclear antibody (ANA) positive patients are typically AMA negative. There are no significant differences in disease phenotype between AMA positive and AMA negative groups. At present, the clinical detection of ANA is mostly by Hep2 immunofluorescence, although ELISA kits for individual nuclear antigens are increasingly becoming available.     

Epitope-specific anti-nuclear antibodies are expressed in a mouse model of primary biliary cirrhosis and are cytokine-dependent

Although the hallmark of primary biliary cirrhosis (PBC) is the presence of anti-mitochondrial antibodies (AMA), a significant number of patients have anti-nuclear antibodies (ANA) directed primarily against two nuclear proteins, gp210 and sp100. In PBC, there are considerable data on the specificity of these anti-nuclear antibodies as well as suggestive evidence that antibodies to gp210 predict a poor outcome. However, a further understanding of the significance of these autoantibodies has been hampered by limitations in accessing human subjects in a preclinical or early asymptomatic stage. To overcome this limitation, we have taken advantage of transgenic mice with abrogated transforming growth factor-β signalling in T cells (dnTGF-βRII) that develop histological features of PBC as well as the same AMA specificity. We studied these mice for serum ANA, including specific autoantibodies against gp210 and sp100. We further examined sera from dnTGF-βRII mice with concurrent deletions of the genes encoding interleukin (IL)-12p35, IL-12p40, IL-23p19, IL-17, IL-6, interferon (IFN)-γ or tumour necrosis factor (TNF)-α. Sera from all the dnTGF-βRII mouse lines contained antibodies against gp210 and sp100. Of significance, mice with germline deletions of the genes encoding IL-12p40, IL-23p19, IL-17, IL-6 and TNF-α had significantly lower titres of anti-gp210 antibodies. These results provide a platform to dissect the mechanisms of gp210 and sp100 autoantibody production in dnTGF-βRII mice as well as to study the possible role of ANA in the pathophysiology of PBC.     

Geographical Differences in Autoantibodies and Anti-infectious Agents Antibodies Among Healthy Adults

Much is known about the geoepidemiology of defined autoimmune diseases (AD); however, there is currently limited data regarding the prevalence of autoantibodies among healthy populations of different geographical areas. The aim of this study was to evaluate a large profile of autoantibodies in healthy adults from distinct global regions as well as the prevalence of anti-infectious agents antibodies in those regions. Sera samples from 557 healthy donors were obtained at six centers located in different countries (i.e., Italy, Netherlands, Israel, Mexico, Columbia, Papua New Guinea (Kitavans)). Sera were tested for the presence of antinuclear antibodies (ANA) and autoantibodies associated with thrombophilia, vasculitis, and gastrointestinal (GI) disease. Sera samples were also screened for antibodies against infectious agents (i.e., EBV, CMV, HBV, Helicobacter pylori, Treponema pallidum, and Toxoplasma gondii). Tests were performed using the BioPlex 2200 or ELISA kits (Bio-Rad Laboratories, USA). We found a significant gradient of ANA positivity among the groups: 45% of Columbians, 38% of Kitavans, 26% of Mexicans, 12% of Italians, 12% of Dutch, and 11% of Israelis were ANA positive. Geographical differences were also observed regarding the prevalence of specific autoantibodies, namely ANA: anti-dsDNA, chromatin, SmRNP, Ro/SSA, La/SSB, Scl70; GI associated: antigliadin; and thrombophilia-associated: anti-??2GP1 and prothrombin. Additionally, significant differences were observed regarding serological markers of all infectious agents screened. The observed variance between healthy ethno-geographical distinct populations in prevalence of autoantibodies may represent different genetic or environmental (e.g., prior exposure to infection) influences. Thus may illuminate possible causes of geoepidemiological differences in AD.     

Autoantibodies in Argentine women with recurrent pregnancy loss

PROBLEM: To determine the presence or absence of subclinical autoimmunity in Caucasian Argentine healthy women with first trimester recurrent pregnancy loss (RPL), the sera of 118 healthy women with a history of three or more consecutive abortions and 125 fertile control women without abortions and two children were analyzed for the presence of autoantibodies: immunoglobulin (Ig)G and IgM anticardiolipin, antinuclear (ANA), antismooth muscle (ASMA), antimitocondrial (AMA), antiliver-kidney-microsomal fraction (LKM), antigastric parietal cells (GPC), antineutrophil cytoplasmatic (ANCA) and antibodies antigliadin type IgA and IgG and IgA antitransglutaminase related with celiac disease (CD). METHOD OF STUDY: ANA, ASMA, AMA, anti-LKM, antibodies to GPC and ANCA were determined by indirect immunofluorescence (IFI) and anticardiolipin, antigliadina and antitransglutaminase antibodies were measured by enzyme-linked immunosorbent assays (ELISA). RESULTS: There was no significant difference between controls and patients with ANA, ASMA, AMA, LKM, ANCA and GPC. The prevalence of anticardiolipin antibodies in RPL was significantly higher than controls (P < 0,01) and the prevalence of positive antibodies for antigliadina type IgA and IgG and IgA antitransglutaminase in RPL was significantly higher than controls (P < 0.04). CONCLUSION: We show that Caucasian Argentine women with RPL showed significantly higher incidence of anticardiolipin antibodies than normal controls and finally we recommended the screening of IgA and IgG antigliadina and IgA antitransglutaminase antibodies in pregnancy, because of the high prevalence of subclinical CD in RPL and the chance of reversibility through consumption of a gluten free diet.     

Autoantibodies in human chronic graft-versus-host disease after hematopoietic cell transplantation

Primary biliary cirrhosis (PBC) and graft-versus-host disease (GVHD) are thought to have common immunopathologic features and previous studies have reported that 5.2 to 81% of patients with chronic GVHD after allogeneic hematopoietic cell transplant have antimitochondrial antibodies (AMA). We studied a total of 89 patients with chronic GVHD and 60 controls for AMA reactivity by ELISA and immunoblotting using recombinant PDC-E2, BCOADC-E2, and OGDC-E2, immunoblotting of beef heart mitochondrial proteins, and reactivity to nuclei, smooth muscle (ASMA), ribonucleoprotein JO-1, extractable nuclear antigen, nuclear proteins SSA/ SSB, ribonucleic P proteinase III, cardiolipin (ACA), liver kidney microsomal, thyroid microsomal, myeloperoxidase, and the reactivity of rheumatoid factor. A subset of 60 chronic GVHD sera were tested for reactivity to gp210 and LBR. Finally, liver tissue from patients with chronic GVHD and PBC was studied by immunohistochemistry to determine whether there was comparable abnormal apical staining of biliary epithelial cells using PDC-E2-specific monoclonal antibodies. Surprisingly, there were no AMA found in the sera from the 89 patients with chronic GVHD. Review of published data on AMA in GVHD suggests that previous results were primarily false positives. In contrast, sera from the patients with GVHD did have a variety of other autoantibodies and, in particular, 20/89 (22.4%) positive ANA, 23/89 (25.8%) positive ASMA, and 9/89 (10.1%) positive ACA. The other autoantibodies assayed were not statistically different from controls. Finally, abnormal biliary epithelial luminal staining of bile ducts was found, as expected, in liver tissue of patients with PBC but was absent in chronic GVHD.     

严重急性呼吸综合征自身免疫指标的初步研究

目的　探讨严重急性呼吸综合征(SARS)患者是否存在着自身免疫现象,寻找患者体内异常出现的抗自身组织器官的抗体。方法　随机选取2 7例SARS患者及18例健康献血员对照血清同时应用免疫荧光法检测抗核抗体(ANA)、抗平滑肌抗体(SMA)、抗线粒体抗体(AMA)、抗胃壁细胞抗体(PCA)、抗心肌抗体(HRA) ,应用酶联免疫吸附试验(ELISA)检测抗肝肾微粒体抗体(LKM)及抗线粒体M2亚型抗体,同时利用猴肺组织基质片应用免疫荧光法定位血清中的SARS相关抗体的靶细胞。结果　2 7例SARS患者中有3例ANA阳性、1例SMA阳性、1例AMA阳性、1例LKM阳性、其余均为阴性;18例献血员中有1例ANA阳性、1例AMA阳性,其余均为阴性。统计分析表明SARS患者与献血员间各项自身抗体阳性率差异均不具有统计学意义。在2 7例SARS患者血清中有2 6例在肺组织细小支气管柱状上皮细胞的腔面尖端呈现强阳性荧光信号,献血员中有5例,统计分析表明两者阳性率差异有统计学意义。结论　SARS患者未出现抗肺外组织、器官的自身抗体。患者血清中出现了抗肺组织的自身抗体,定位于细小支气管柱状上皮细胞。     

Prevalence of non-organ-specific autoantibodies in a rural community from northeastern Brazil: a population-based study

Non-organ-specific autoantibodies (NOSA) are well-recognized diagnostic markers of autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC), but can also be observed in patients with viral hepatitis as well as in healthy subjects. The aim of this study was to evaluate the prevalence of NOSA in subjects living in a rural community in Brazil and to correlate their occurrence with the presence of liver disease. Seven hundred twenty-five apparently healthy subjects were randomly selected for assessment of antinuclear (ANA), anti-smooth muscle (SMA), antimitochondrial (AMA), anti-liver/kidney microsome type 1, and anti-liver cytosol type 1 antibodies. Subjects with those NOSA were evaluated for the presence of AIH, PBC, and viral hepatitis. Reactivities for all NOSA, SMA, ANA, and AMA were detected, respectively, in 14, 10, 4, and 0.1% of subjects, with a mean titer of 1:40. NOSA-positive subjects were significantly older and more frequently females. No correlation was observed between the occurrence of NOSA and PBC, AIH, or viral hepatitis. The prevalence of NOSA in Brazilians was 14%. They were usually low titer. NOSA were more frequently observed in females and older subjects and their presence was not correlated with the presence of AIH, PBC, or viral hepatitis.     

Immunoserological area--with special reference to the current topics on antinuclear antibodies

In 1948, Hargraves described the phenomenon of the LE cells and equated it with systemic lupus erythematosus (SLE). Kunkel and his colleagues elucidated the immunochemical basis of this phenomenon, showing that it was related to the circulating autoantibodies to deoxyribonucleoprotein (DNP). Their pioneering studies led to the continuing discoveries of antinuclear antibodies (ANA) and today's considerable knowledge concerning the molecular identity of antigens and further consolidation of ANA. In addition to the role of diagnostic markers, spontaneously occurring autoantibodies, including anti-PCNA (proliferating cell nuclear antigen) antibody and anticentromere antibody (ACA), turned out to be useful as powerful probes for cell biology. In this study, the sera of patients with primary biliary cirrhosis (PBC) along with collagen diseases were examined for the presence of antinuclear antibodies. In using HEp-2 cells and chromosomes derived from K 562 as the substrates for the immunofluorescence method, the frequency of ANA and ACA in PBC sera were 84% and 44% respectively. Anti-DNA, antiSS-A and antiSS-B antibodies were found in one, 4 and one sera respectively. On the other hand, antibodies to nRNP, Sm and Scl-70 were not found in PBC sera. In some PBC patients with ACA, various complications related to collagen diseases were found to coexist. Our results indicated that there might be common serological abnormalities among patients with PBC, CREST syndrome and Sj?gren's syndrome.     

Do Autoantibodies Predict Autoimmune Liver Disease in Primary Sjögren's Syndrome? Data of 180 Patients upon a 5 Year Follow‐Up

Objective: To evaluate the clinical value of autoantibodies as serological markers to predict autoimmune liver diseases in primary Sjögren's syndrome (SS). Materials and methods: 180 patients who met the European diagnostic criteria for SS but without a history of liver disease were studied upon a 5 year follow‐up. Sera taken at enrolment were evaluated by immunofluorescence analysis (IF‐AMA) on rat liver, stomach and kidney sections, enzyme‐linked immunosorbent assay using rat mitochondrial, microsomal and soluble liver antigens and Western blot (WB) analysis using rat mitochondrial antigens. Results: At presentation, 152 (84%) sera had autoantibodies. Antinuclear antibodies (ANA) were expressed in 58% of patients and displayed three distinct patterns (speckled, homogenous and anticentromere). Smooth muscle autoantibodies (SMAs) and parietal cell autoantibodies were found in 39 and 4.5% of patients, respectively. Three patients presented antimitochondrial antibodies by IF‐AMA, and two of them developed symptomatic primary biliary cirrhosis (PBC). Two patients without IF‐AMA and without evidence of cholestasis had PBC‐specific AMA (anti‐PDC–E2 and anti‐BCKADC–E2). However, these two patients and the third IF‐AMA‐positive woman remained free from symptoms and biochemical signs of PBC. Autoimmune hepatitis (AIH) (n = 2), ‘overlap syndrome’ of AIH and chronic hepatitis C (n = 1) and autoimmune cholangiopathy (AIC) (n = 1) were diagnosed in four patients. Conclusions: Patients with IF‐AMA usually develop symptomatic PBC upon a 5 year follow‐up. Our findings support the idea that patients without IF‐AMA, who express PBC‐specific AMA, are in early, asymptomatic stage of the disease. High‐titre SMA and IF‐AMA are the most specific indicators for AIH and PBC.     

Primary biliary cirrhosis: assessment of the quantitative importance of the adenine nucleotide translocator protein as a major mitochondrial antigen.

The adenine nucleotide translocator protein (ANT) is the first well-characterized mitochondrial polypeptide to be identified as an antigen for antimitochondrial autoantibodies (AMA) in PBC sera. Because of the potential use for a highly purified antigen as a tool in studying the aetiology of PBC, we have undertaken an assessment of the quantitative importance of ANT as a PBC-specific mitochondrial antigen. Immunoblotting and ELISA techniques were used. Both methods reveal PBC antibodies against isolated rat liver ANT. However, competitive ELISA experiments using purified rat liver ANT as the competing antigen show that anti-ANT antibodies in PBC serum comprise only a fraction of the total AMA. Furthermore, both ELISA and immunoblotting experiments show that rat liver ANT is not a specific antigen for PBC autoantibodies. Sera from patients with SLE, chronic active hepatitis, and sera from normal, control patients, have nearly the same, or higher, ANT antibody titres. Thus, ANT is not a good candidate as an antigen for the diagnosis of PBC.     

Detection and characterization of liver membrane autoantibodies in chronic active hepatitis by a solid-phase radioimmunoassay.

A solid-phase radioimmunoassay was developed to detect antibodies to liver membrane antigens in sera of patients with HBsAg-negative and -positive liver diseases and primary non-hepatic autoimmune diseases. Ten of fourteen patients with HBsAg-negative CAH had autoantibodies detected by RIA; negative results were obtained with sera of seven patients with HBsAg-positive acute and chronic liver diseases, six patients with miscellaneous liver diseases, including two patients with PBC, two healthy blood donors and seven patients with primary non-hepatic autoimmune diseases. Antibodies detected by RIA correlated with liver membrane autoantibodies (LMA) found by indirect immunofluorescence; no correlation was observed with AMA, ANA and SMA. Species-cross-reacting antibodies could be absorbed by preincubation with isolated plasma cell membranes prepared from rabbit livers. Liver membrane autoantibodies detected by RIA were directed against three different antigen fractions obtained from Sepharose 6B chromatography including LSP and LM-Ag. Only three of ten antibodies were directed against species-specific determinants; others cross-reacted with rabbit antigens. Only the antibody to LSP was organ-specific, all others cross-reacted with kidney proteins. Ferritin, human serum albumin and human plasma lipoprotein were excluded as target antigens. Although several sera reacted with identical molecules a remarkable heterogeneity of liver membrane autoantibodies was observed.     

Autoantibodies associated with primary biliary cholangitis are common among patients with systemic lupus erythematosus even in the absence of elevated liver enzymes

Knowledge of concomitant autoimmune liver diseases (AILD) is more detailed in primary Sjögren’s syndrome (pSS) compared to systemic lupus erythematosus (SLE). Herein, the prevalence of autoantibodies associated with autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) was investigated in stored sera from patients with SLE (n = 280) and pSS (n = 114). Antibodies against mitochondria (AMA), liver–kidney microsomal (LKM) antigen, smooth muscle (SMA) and anti‐nuclear antibodies (ANA) were analysed with immunofluorescence microscopy. In addition, AILD‐associated autoantibodies were tested with immunoblot. Prior to sampling, eight SLE (2·9%) and three pSS (2·6%) cases were diagnosed with AILD. Among SLE‐cases without known AILD (n = 272), 26 (9·6%) had PBC‐associated autoantibodies, 15 (5·5%) AIH‐associated autoantibodies (excluding ANA) and one serological overlap. Most subjects with PBC‐associated autoantibodies had liver enzymes within reference limits (22 of 27, 81%) or mild laboratory cholestasis (two of 27, 7·4%), while one fulfilled the diagnostic PBC‐criteria. AMA‐M2 detected by immunoblot was the most common PBC‐associated autoantibody in SLE (20 of 272, 7·4%). The prevalence of SMA (4·4%) was comparable with a healthy reference population, but associated with elevated liver enzymes in four of 12 (25%), none meeting AIH‐criteria. The patient with combined AIH/PBC‐serology had liver enzymes within reference limits. Among pSS cases without known AILD (n = 111), nine (8·1%) had PBC‐associated, 12 (10·8%) AIH‐associated autoantibodies and two overlapped. PBC‐associated autoantibodies were found as frequently in SLE as in pSS but were, with few exceptions, not associated with laboratory signs of liver disease. Overall, AILD‐associated autoantibodies were predominantly detected by immunoblot and no significant difference in liver enzymes was found between AILD autoantibody‐negative and ‐positive patients.     

A follow-up study of 68 patients with anti-mitochondrial antibodies (AMA)

During the period 1976-83, anti-mitochondrial antibodies (AMA) were detected in 68 patients out of about 48 000 sera (0.14%) analyzed for a repertoire of autoantibodies at the Department of Immunology, University Hospital of Troms?. Fifty-five of these patients were women, and only 10 had unequivocal primary biliary cirrhosis (PBC). At follow-up in 1984, 48 out of these 68 patients were accessible for complementary testing. The AMA test became negative in 17 of these 48 patients during the observation period. Eleven of these 17 had originally a titer of 50. Seven of the 31 patients with persistent AMA were without detectable liver pathology. One patient had antibodies against smooth muscle, one against cell nucleus, whereas 35 had an increased serum IgM level. In conclusion, most patients with AMA do not have obvious PBC, a low AMA titer is likely to be transient, and there is a strong association between AMA and an increased serum IgM level.     

原发性胆汁肝硬化患者血清中抗线粒体抗体及其亚型和抗核抗体的联合检测的临床价值

为了分析原发性胆汁性肝硬化(primary biliary cirrhosis,PBC)患者的抗线粒体抗体(anti-mitochondria antibody,AMA)及其M2、M4、M9亚型、抗核抗体(antinuclear antibody,ANA)的阳性率。应用间接免疫荧光法检测ANA、AMA,免疫斑点法检测AMA M2、M4、M9。结果显示91例PBC患者中AMA有89例为阳性。其中96.7%(88/91)的患者M2型阳性,45.1%(41/91)M4型阳性,2.2%(2/91)M9型阳性。39/91例患者ANA阳性,其中21例为核膜型。ANA、AMA及其M2、M4、M9亚型联合检测对于PBC患者的诊断有重要价值。     

Antimitochondrial (pyruvate dehydrogenase) antibodies in leprosy

Sera from 69 patients with leprosy but without liver involvement were assayed for the presence of mitochondrial pyruvate dehydrogenase (PDH)-specific autoantibodies by enzyme-linked immunoabsorbent assay (ELISA), immunoblotting using PDH as an antigen and by enzymatic inhibition test. Twenty-seven of the leprosy serum samples (39.1%) were found to react with PDH by ELISA. However, unlike sera from primary biliary cirrhosis (PBC) patients, none of these were able to inhibit the PDH enzymatic activity. By immunoblotting, it was found that only 2 of the 27 positive sera recognized the 74-kD protein of the PDH complex, which is recognized by sera of most PBC patients. The antimitochondrial antibodies in lepra most probably recognize different epitopes than those in PBC. These findings may indicate that anti-PDH autoantibodies in patients with leprosy may arise by polyclonal B cell stimulation and may represent natural anti-PDH autoantibodies.     

Clinical significance and prevalence of anti-Saccharomyces cerevisiae antibody in Chinese patients with primary biliary cirrhosis

Clinical significance of anti-Saccharomyces cerevisiae antibody (ASCA) and its prevalence in Chinese primary biliary cirrhosis (PBC) patients have not been characterized and therefore needs to be defined. Enzyme-linked immunosorbent assay was used to test ASCA in sera from 198 PBC patients, 85 patients with other liver diseases (OLD) and 35 health controls (HC). Indirect immunofluorescence was used to detect anti-mitochondrial antibodies (AMA) in PBC. Results showed that the frequency of ASCA in PBC, 29.8 %, was higher than other disease groups. And ASCA occurred more frequently in PBC patients with positive anti-gp210 than the negative ones. Also, ASCA was detected in 7 out of 15 PBC negative for AMA. Some liver-related biochemical indices and inflammatory indices were significantly higher in PBC patients with positive ASCA (p < 0.05). In conclusion, the prevalence of ASCA in Chinese PBC patients is 29.8 %. PBC patients with positive ASCA are associated with more severe liver injury, and ASCA-IgA might be related to disease activity of PBC.     

Diversity of autoantibodies in primary biliary cirrhosis and chronic active hepatitis

The presence of autoantibodies in the serum of 110 patients with primary biliary cirrhosis (PBC), 50 with HBsAg negative chronic active hepatitis (HBsAg- CAH) and 30 with HBsAg positive chronic active hepatitis (HBsAg+ CAH) was assessed using two methods: indirect immunofluorescence on cells grown in tissue culture (HEp-2 cell line) or standard mouse tissue sections, and counter immunoelectrophoresis (CIE) with soluble tissue extracts. Anti-nuclear antibodies (ANA) were found in 38% of sera from patients with PBC using HEp-2 cells compared with 10% using mouse tissue. A variety of staining patterns were detected including a pattern of multiple nuclear dots. In contrast, ANA was detected in 70% of sera from patients with HBsAg- CAH and 27% with HBsAg+ CAH. Using CIE four distinct antibody antigen systems were detected: Ro (SS-A), La (SS-B) and two new systems, designated XH and XR, reacting with extracts of human spleen and rabbit thymus, respectively. Correlation of the presence of antibody with clinical conditions confirmed the close association between anti-centromere antibody and sclerodactyly in patients with PBC and indicated an association between 'multiple nuclear dot' staining and the sicca syndrome in PBC. No association was found between the presence of either Ro or La antibody and the sicca syndrome in patients with PBC.     

Clinical significance of positive immunoblotting but negative immunofluorescence for antimitochondrial antibodies in patients with liver diseases other than primary biliary cirrhosis

The serum reaction to anti-2-oxo-acid dehydrogenase complex (2-OADC) enzymes, the antigens recognized by antimitochondrial antibodies (AMA), can be detected by immunoblotting in patients with liver diseases other than primary biliary cirrhosis (PBC), who are negative for AMA by conventional indirect immunofluorescence. Whether the presence of anti-2-OADC is related to PBC or represents preclinical PBC in such patients is obscure at present. We examined the immunoreactivity of AMA by immunofluorescense, immunoblotting, and enzyme inhibition assay in serum samples from 59 patients with liver diseases other than PBC and 71 healthy subjects. We also examined the clinical course of the patients in whom a positive result was obtained to elucidate whether such reaction was a "true" or "false" phenomenon. None of the 130 sera was positive for AMA by indirect immunofluorescence or for anti-pyruvate dehydrogenase complex (PDC) by enzyme inhibition assay. However, seven of 71 (10%) sera from healthy subjects contained weak IgG class antibody to PDC-E2 (four sera) or E2 subunit of branched-chain oxo-acid dehydrogenase complex (BCOADC-E2) (three sera). Of the 59 sera from patients with liver diseases other than PBC, four (7%) reacted against 2-OADC by immunoblotting. Of these, three sera were from patients with chronic hepatitis C virus (HCV) infection, and contained IgG class autoantibody to BCOADC-E2. The serum reactivity to BCOADC-E2 detected by immunoblotting in these three patients diminished after absorption with recombinant BCOADC-E2 fusion protein. During the 3-5 year follow-up period, AMA by immunofluorescence and anti-PDC activity by enzyme inhibition assay were always negative in these three patients. The other one serum was from patient with alcoholic cirrhosis, and contained IgM class autoantibody to E3 binding protein (E3-BP). This patient did not develop PBC during the following 2 years. Our results showed that anti-2-OADC antibodies could be detected in some patients with liver diseases other than PBC, and even in healthy individuals. The clinical significance of the presence of these serum reactions is obscure at this stage, but the production of anti-BCOADC-E2 may be linked to the presence of HCV in certain patients. Further prospective studies of larger population should clarify whether anti-2-OADC reaction can precede the clinical development of PBC.