Serum autoantibodies: a road map for the clinical hepatologist

Optimization of Laboratory Diagnostics of Primary Biliary Cholangitis: When Solid-Phase Assays and Immunofluorescence Combine

The laboratory diagnostics of primary biliary cholangitis (PBC) have substantially improved, thanks to innovative analytical opportunities, such as enzyme-linked immunosorbent assays (ELISA) and multiple immunodot liver profile tests, based on recombinant or purified antigens. This study aimed to identify the best diagnostic test combination to optimize PBC diagnosis. Between January 2014 and March 2017, 164 PBC patients were recruited at the hospitals of Parma, Modena, Reggio-Emilia, and Piacenza. Antinuclear antibodies (ANA) and anti-mitochondrial antibodies (AMA) were assayed by indirect immunofluorescence (IIF), ELISA, and immunodot assays (PBC Screen, MIT3, M2, gp210, and sp100). AMA-IIF resulted in 89.6% positive cases. Using multiple immunodot liver profiles, AMA-M2 sensitivity was 94.5%, while anti-gp210 and anti-sp100 antibodies were positive in 16.5% and 17.7% of patients, respectively. PBC screening yielded positive results in 94.5% of cases; MIT3, sp100, and gp210 were detected by individual ELISA test in 89.0%, 17.1%, and 18.9% of patients, respectively. The association of PBC screening with IIF-AMA improved the diagnostic sensitivity from 89.6% to 98.2% (p < 0.01). When multiple immunodot liver profile testing was integrated with AMA-IIF, the diagnostic sensitivity increased from 89.1% to 98.8% (p < 0.01). The combination of IIF with solid-phase methods significantly improved diagnostic efficacy in PBC patients.

Fluctuations of antimitochondrial antibodies and anti-gp210 antibody in a patient with primary biliary cholangitis and Sjögren syndrome with subsequent autoimmune hemolytic anemia: A case report

RATIONALE

Primary biliary cholangitis (PBC) is a rare autoimmune cholestatic liver disease. It is often associated with extrahepatic autoimmune disorders. However, the concurrence of PBC and Sjögren syndrome (SS) with the subsequent onset of autoimmune hemolytic anemia (AIHA) is extremely rare.

PATIENT CONCERNS

This study investigated a 60-year-old woman admitted to our hospital with complaints of xerostomia for 5 years, pruritus for 3 years, and abnormal liver function for 3 months.

DIAGNOSES

The patient was suffering from typical clinical PBC and SS, and developed decompensated liver cirrhosis after 32 months of ursodeoxycholic acid (UDCA) therapy. In May 2018, she was readmitted to the hospital with a high fever of 39 °C, coughing, and sever fatigue without remission after 3 days of cephalosporin antibiotic therapy. During the clinical course of PBC, her antimitochondrial antibodies (AMA) titers fluctuated from 1:1000 to negative and then to weakly positive, determined by indirect immunofluorescence (IIF), immunoblotting, and enzyme-linked immunosorbent assay (ELISA) based on recombinant mitochondrial antigens; furthermore, her titers of anti-gp210, an antinuclear antibody (ANA), increased sharply. Laboratory tests and imaging were performed to diagnose PBC and SS in September 2015. However, she was subsequently diagnosed with AIHA after 32 months of UDCA therapy based on the identification of pancytopenia, increased reticulocyte (RET) count, and a positive result from the direct Coombs test.

INTERVENTIONS

UDCA, hepatic protectant, albumin infusion, chest drainage, rational antibiotic use, diuretics, and methylprednisolone were used to treat the patient.

OUTCOMES

Liver cirrhosis was complicated by the development of AIHA, which became severe at 42 months of follow-up.

LESSONS

This is the first case report showing a patient with comorbid PBC and SS, as well as the sequential development of AIHA with decreased AMA and increased anti-gp210 titers; this may have been due to immunodeficiency. These findings stress the importance of the serological screening of ANA profile, as well as repeated measurement of ANA and AMA to track PBC progression and prognosis.

Clinical relevance of combined anti-mitochondrial M2 detection assays for primary biliary cirrhosis

BACKGROUND

Antimitochondrial antibody (AMA) is a specific serologic marker in primary biliary cirrhosis (PBC). The aim of this study was to evaluate the clinical relevance of combined AMA assays.

METHODS

Sera were obtained from 79 patients with PBC and 108 patients with other liver disease. They were tested by indirect immunofluorescence (IIF) using rat kidney/stomach tissue and HEp2 cells as substrate, 4 AMA-M2 assays, anti-sp100, and anti-gp210 assays.

RESULTS

Using IIF-AMA with cut-off titer of 1:40, the sensitivity and specificity for PBC were 88.6% and 87.0%, respectively. A cut-off titer of 1:80 improved the specificity to 93.5%. The 4 commercial assay kits using AMA-M2 autoantibodies showed sensitivity of 55.7-79.7% and specificity of 91.7-95.4% with moderate to good agreement. AMA-M2 assays using both native and recombinant E2 antigens had higher sensitivity. ANAs on HEp2 cells, anti-sp100, and anti-gp210 were detected in 67.1%, 13.9-15.2%, and 22.8-27.8% of PBC patients, respectively. Additional AMA-M2 specific assays in IIF-AMA negative and low titer positive (1:40) sera increased the sensitivity and specificity to 88.6% and 90.7%, respectively.

CONCLUSIONS

Serological diagnosis for PBC using IIF with high titer cut-off and additional AMA-M2 specific tests by ELISA or LIA in IIF-negative sera should be used.

Autoantibody Profile of Adult Patients With Childhood Onset Type 2 Autoimmune Hepatitis

BACKGROUND

Anti-liver kidney microsome (anti-LKM) autoantibodies are a distinguishing feature of type II autoimmune hepatitis (AIH-2). However, the levels of anti-LKM-1 in adult AIH-2 patients and their role in liver immunopathology remain equivocal. The aim of the study was to survey the autoantibody profile and the activity of liver disease in adult patients diagnosed with AIH-2 at childhood.

METHODS

The autoantibody profile of adults was compared with the autoantibodies of the pediatric period. Liver function test, Immunoglobulin G (IgG), and gamma globulins were evaluated at the AIH presentation, at the age of 18 years, and at the current adult visit.

RESULTS

All ten patients tested positive for LKM-1 at least once during the pediatric period. At the adult visit, four patients lost autoantibody positivity. LKM-1 was positive in four, liver cytosol antigen 1 (LC-1) in two, soluble liver antigen in one, and antinuclear antigen in one patient. Additionally three patients with LKM-1 and one patient without LKM-1 were positive for AMA-M2 (where AMA is antimitochondrial antibodies) Immunoglobulin M (IgM). Liver function markedly improved at 18 years and adult visit compared with initial diagnosis of AIH with only a mild decrease of IgG. The six adult patients positive for at least one autoantibody had statistically lower aspartate aminotransferase (AST) and gamma-glutamyltranspeptidase (GGTP) than the four patients autoantibody negative (AST: 52 vs. 88 IU/l, P < 0.05; GGTP 19 vs. 163 IU/l, P < 0.05).

CONCLUSION

LKM-1 positivity is not a stable condition in all patients with AIH-2. Patients who remained autoantibody positive had better liver function tests than those who lost their positivity. The presence of AMA-M2 autoantibodies suggest that development of AIH/Primary Biliary Cirrhosis (PBC) overlap syndrome should be considered.

Autoantibodies in Chinese patients with chronic hepatitis B: Prevalence and clinical associations

AIM: To investigate the prevalence of autoantibodies and their associations with clinical features in Chinese patients with chronic hepatitis B (CHB).

METHODS: A total of 325 Chinese patients with CHB were enrolled in this retrospective, hospital-based study. Patients with chronic hepatitis C (CHC), autoimmune hepatitis (AIH), or primary biliary cirrhosis (PBC) were included, with healthy donors acting as controls. A panel of autoantibodies that serologically define AIH and PBC was tested by indirect immunofluorescence assay and line immunoassay. The AIH-related autoantibody profile included homogeneous anti-nuclear antibodies (ANA-H), smooth-muscle antibodies, anti-liver kidney microsome type 1, anti-liver cytosolic antigen type 1, and anti-soluble liver antigen/liver pancreas; the PBC-related antibodies were characterized by ANA-nuclear dots/membranous rim-like, anti-mitochondrial antibodies-M2 (AMA-M2), anti-BPO (recombinant antigen targeted by AMA-M2), anti-Sp100, anti-promyelocytic leukemia protein (anti-PML), and anti-gp210. The dichotomization of clustering was used to unequivocally designate the AIH or PBC profiles for each case. Anti-Ro52 antibodies were also tested.

RESULTS: The prevalence of any autoantibody in CHB amounted to 58.2%, which was similar to the 66.2% prevalence in CHC, significantly higher than the 6.7% in the healthy controls (P < 0.001), and lower than the 100% found in AIH and PBC (P = 0.004 and P < 0.001, respectively). There were more anti-PML and anti-gp210 antibodies among the CHB patients than the CHC patients (11.1% vs 0%, P = 0.003; 12.6% vs 0%, P < 0.001, respectively). The prevalence and titer of AMA, anti-BPO, anti-PML, and anti-gp210 were higher in PBC than in those with CHB. Among the CHB patients, the prevalence of ANA, especially ANA-H, was significantly lower in patients with compensated and decompensated cirrhosis compared with patients without cirrhosis. Thirty-eight cases of hepatocellular carcinoma (HCC) in CHB showed a significant difference compared with non-HCC patients in the prevalence of anti-PML (0% vs 12.5%, P = 0.013). Dichotomization of the autoantibodies revealed that the PBC profile was more prevalent in patients with CHB than in those with CHC, and that it was strongly correlated with both compensated and decompensated cirrhosis. In contrast, the prevalence of the AIH profile was significantly higher in non-cirrhosis patients with CHB than in those with compensated cirrhosis (18.5% vs 8.2%, P = 0.039). Moreover, the AIH profile was also closely associated with hepatitis B e-antigen positivity.

CONCLUSION: ANA-H could be an indicator of early-stage CHB. Dichotomizing the autoantibody profiles revealed that the PBC profile is strongly associated with cirrhosis in CHB.

Autoantibody Profiling in a Cohort of Pediatric and Adult Patients With Autoimmune Hepatitis

BACKGROUND

Autoimmune hepatitis (AIH) is a rare condition characterized by the presence of autoantibodies distinctive of type 1 AIH (AIH-1) and type 2 AIH (AIH-2). The aim of this study was to evaluate the autoantibody profile in a cohort of pediatric and adult AIH patients, using both indirect immunofluorescence (IIF) and a new multiplexed line-blot assay.

METHODS

Sera from 63 pediatric and 53 adult AIH patients were tested for antinuclear (ANA), antismooth muscle (SMA), anti-liver kidney microsome 1 (anti-LKM1), anti-liver cytosol 1 (anti-LC1) autoantibodies using IIF methods; for anti-LKM1, anti-LC1, and soluble liver antigen/liver-pancreas (anti-SLA/LP) autoantibodies using the line-blot; for anti-F-actin autoantibodies using IIF both on VSM47 cell-line and on rat intestinal epithelial cells.

RESULTS

AIH-1 was the most common type of AIH in the adult cohort (73.6%), while AIH-2 was the most common AIH in the pediatric cohort (61.9%). Both in adult and pediatric AIH-2 anti-LKM1 were the prevalent autoantibodies. In pediatric AIH-2 anti-LC1 autoantibodies were more frequent than in adult AIH-2 (59 vs. 28.6%), and in 35.9% of cases they were present alone. In 17 patients anti-LC1 autoantibodies were detected only with the line-blot assay. The levels of anti-LKM1 and of anti-LC1 were not different between adult and pediatric AIH, and the overall agreement between the results obtained with the two IIF methods for F-actin detection was 98.8% (CI 95%: 94.4-99.7%).

CONCLUSIONS

The line-blot assay showed a higher sensitivity than IIF for anti-LC1 detection. Anti-LKM1 and anti-LC1 autoantibody levels are not different in adults and children. An almost perfect agreement between the two IIF methods for anti-F-actin detection has been observed.

Efficacy of combined antiviral therapy with lamivudine and tenofovir in a liver transplanted girl with de novo hepatitis B virus infection

The management of de novo hepatitis B (HBV) infection in children after liver transplantation is not well defined. Because this infection may induce severe liver disease in the graft liver, an efficient antiviral therapy is desirable. Here, we describe the favorable viral outcome observed in a liver transplanted girl with de novo HBV infection following combination therapy with lamivudine and tenofovir.

Autoimmune hepatitis type 2 associated with an unexpected and transient presence of primary biliary cirrhosis-specific antimitochondrial antibodies: a case study and review of the literature

Background

Unlike other autoimmune liver diseases, primary biliary cirrhosis (PBC) has never been reported in early childhood, while type 2 autoimmune hepatitis (AIH) is eminently a paediatric disease.

Case presentation

We describe a case of type 2 AIH with serological positivity for PBC-specific anti-mitochondrial antibodies (AMA) in a 3-year old girl. We found this observation intriguing as AMA and indeed an overlap with PBC are virtually absent in Type 2 AIH, a pediatric form of AIH which is distinct precisely because it is characterized by pathognomonic anti-liver kidney microsomal type 1 (LKM-1) showing a remarkable antigen-specificity directed against cytochrome P4502D6. We also review the literature in relation to AMA positivity in paediatric age and adolescence. In our case, the presence of AIH-2-specific anti-LKM-1 and PBC-specific AMA was confirmed by indirect immunofluorescence (IIF), and immunoblotting and ELISA based on recombinant mitochondrial antigens. The clinical, laboratory and histological features of the child are given in detail. Interestingly the mother was AMA positive without other features of PBC. The child was successfully treated with immunosuppression and five years after the original diagnosis is on a low dose of prednisolone and azathioprine, with no signs of relapse. Anti-LKM-1 antibodies are still present in low titres. AMA were detectable for the first 4 years after the diagnosis and disappeared later.

Conclusion

This is the first case report in the literature of AIH type 2 with an unexpected PBC-specific AMA positivity in a young child. Response to immunosuppressive treatment was satisfactory and similar to that described in AIH. A review of published reports on AMA positivity in paediatric age shows that the antibody may arise in the context of immunodeficiency and is variably associated with liver damage.

The autoimmunity of primary biliary cirrhosis and the clonal selection theory

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease in which an immune-mediated injury targets the small intrahepatic bile ducts. PBC is further characterized by highly specific serum antimitochondrial autoantibodies (AMA) and autoreactive T cells, a striking female predominance, a strong genetic susceptibility, and a plethora of candidate environmental factors to trigger the disease onset. For these reasons PBC appears ideal to represent the developments of the clonal selection theory over the past decades. First, a sufficiently potent autoimmunogenic stimulus in PBC would require the coexistence of numerous pre-existing conditions (mostly genetic, as recently illustrated by genome-wide association studies and animal models) to perpetuate the destruction of the biliary epithelium by the immune system via the persistence of forbidden clones. Second, the proposed modifications of mitochondrial autoantigens caused by infectious agents and/or xenobiotics well illustrate the possibility that peculiar changes in the antigen structure and flexibility may contribute to tolerance breakdown. Third, the unique apoptotic features demonstrated for cholangiocytes are the ideal setting for the development of mitochondrial autoantigen presentation to the immune system through macrophages and AMA thus turning the non traditional mitochondrial antigen into a traditional one. This article will review the current knowledge on PBC etiology and pathogenesis in light of the clonal selection theory developments.

Primary biliary cirrhosis: What do autoantibodies tell us?

Primary biliary cirrhosis (PBC) is a chronic, progressive, cholestatic, organ-specific autoimmune disease of unknown etiology. It predominantly affects middle-aged women, and is characterized by autoimmune-mediated destruction of small- and medium-size intrahepatic bile ducts, portal inflammation and progressive scarring, which without proper treatment can ultimately lead to fibrosis and hepatic failure. Serum autoantibodies are crucial tools for differential diagnosis of PBC. While it is currently accepted that antimitochondrial antibodies are the most important serological markers of PBC, during the last five decades more than sixty autoantibodies have been explored in these patients, some of which had previously been thought to be specific for other autoimmune diseases.

[Autoimmune hepatitis: diagnostic and therapeutic up-to-date]

Autoimmune hepatitis is a disorder of unknown aetiology that occurs in children and adults of all ages with a female predominance. The spectrum of presentation is wide, ranging from no symptoms to acute liver failure. The diagnosis is based on high level serum gammaglobulins, characteristic circulating autoantibodies and histologic abnormalities (necrosis and inflammation). Autoimmune hepatitis is classified on the basis of the autoantibody pattern: type 1 (antinuclear and/or smooth muscle antibodies) is the classic form whereas type II (liver-kidney microsome 1 antibody) is much less common and occurs mainly in childhood. Mixed forms of autoimmune hepatitis that share features with other putative autoimmune liver diseases, primary biliary cirrhosis and primary sclerosing cholangitis, have been described. Because of therapeutic issues, it is important to distinguish autoimmune hepatitis from other forms of hepatitis and the use of diagnostic scoring systems may be helpful. The treatment of autoimmune hepatitis has not changed for the past 30 years. It consists of corticosteroids associated with azathioprine. This treatment is rapidly effective but usually only suspensive. Relapse after treatment withdrawal is the rule (80% of cases). The main risk factor of recurrence is the degree of residual inflammation on liver biopsy. The frequency of side effects justifies an attempt of drug discontinuation provided that criteria of clinical, biochemical and histological remission are achieved after at least 2 years of treatment.

[A case of autoimmune hepatitis]

Autoimmune hepatitis (AIH) is a disorder of unknown aetiology that occurs in children and adults of all ages with a female predominance. The spectrum of presentation is wide, ranging from no symptoms to acute liver failure. The diagnosis is based on high level or serum gammaglobulins, characteristic circulating autoantibodies and histologic abnormalities (necrosis and inflammation) in the absence of other causes. AIH is classified on the basis of the autoantibody pattern: type 1 (antinuclear and/or smooth muscle antibodies) is the classic form whereas type 2 (liver-kidney microsome 1 antibody) is much less common and occurs mainly in childhood. Mixed forms of AIH that share features with other putative autoimmune liver diseases, primary biliary cirrhosis and primary sclerosing cholangitis, have been described. Because of therapeutic issues, it is important to distinguish AIH from other forms of hepatitis and the use of diagnostic scoring systems may be helpful. Treatment basis of AIH have not changed for the last 30 years. Initial treatment consists of corticosteroids associated with azathioprine. Budesonide may be at least as effective as systemic corticosteroids and reduces the frequency of side effects in non-cirrhotic patients. Long-term treatment consists of azathioprine. This treatment is rapidly effective but usually only suspensive since relapse after treatment withdrawal is the rule (80 % of cases). The probability of relapse is lower in case of complete biochemical response defined by normalization of transaminases, gamma-globulins and IgG and in case of histological response defined by the lack of interface hepatitis. The frequency of side effects justifies an attempt of drug discontinuation provided that criteria of clinical, biochemical and histological remission are achieved after at least 2 years of treatment.

Multiple nuclear dots and rim-like/membranous IgG isotypes in primary biliary cirrhosis

Anti nuclear (ANA) immunomorphological patterns such as multiple nuclear dots (MND) and rim-like/membranous (RL/M) are considered highly specific but little sensitive for primary biliary cirrhosis (PBC) diagnosis. To evaluate frequency and clinical significance of MND and RL/M in PBC patients when investigated at the level of immunoglobulin G isotypes. MND and RL/M pattern have been tested in 141 PBC sera and 230 pathological controls using HEp-2 cells as substrate and anti- total IgG and individual IgG subclasses (IgG1, IgG2, IgG3, IgG4) as specific antisera. One hundred and fourteen of 141 (80%) PBC patients had RL/M or MND pattern when IgG subclasses were used as revealing reagents (vs. 34% when anti total IgG were used, p < 0.0001). The prevalent isotype was IgG1 for RL/M, and IgG2 for MND pattern. None of controls was positive. No clinical differences in terms of severity and outcome of disease have been observed in PBC patients positive for MND and RL/M when investigated with IgG isotypes. The research for RL/M and MND pattern at level of IgG isotype determines a wide gain in terms of sensitivity without a loss of specificity. In Italian PBC patients MND and RL/M pattern did not seem to characterize any subgroup of patients with a poorer prognosis.

Increased expression of Collagen I and Collagen III induced by HBV in hepatic stellate cells

AIM: To investigate whether HepG2.2.15 could induce expression of fibrosis-related factors in hepatic stellate cells in vitro and further to explore the mechanism of HBV inducing fibrogenesis.

METHODS: The hepatic stellate cells were co-cultured with HepG2 or HepG2.2.15 in vitro and the hepatic stellate cells cultured alone were used as control. For differentiation mRNA expression of Collagen I and III in hepatic stellate cells, real-time PCR was performed; for differentiation protein expression of Collagen I and III in hepatic stellate cells, Western blot analysis was performed.

RESULTS: Compared with the control and the hepatic stellate cells co-cultured with HepG2, mRNA expression of Collagen I and III were significantly higher in the hepatic stellate cells co-cultured with HepG2.2.15 and the most prominent effect was found at 72 h (P < 0.01); the protein expression of Collagen I and III were higher significantly in the hepatic stellate cells co-cultured with HepG2.2.15 and the most prominent effect was found at 48 h compared with control and the hepatic stellate cells co-cultured with HepG2 (P < 0.01).

CONCLUSION: The expression of fibrosis-related factors in hepatic stellate cells are increased greatly after being co-cultured with HepG2.2.15. HBV is capable of inducing fibrogenesis in vitro.

Hepatitis B virus induces expression of connective tissue growth factor and transforming growth factor-β1 in hepatic stellate cells

AIM: To investigate whether HepG2.2.15 cell line induces the expression of connective tissue growth factor (CTGF) and transforming growth factor-β1 (TGF-β1) in hepatic stellate cells and the mechanism of hepatitis B virus (HBV) in inducing fibrogenesis.

METHODS: The hepatic stellate cells (LX-2) were co-cultured with HepG2 or HepG2.2.15 in vitro and the LX-2 cells cultured alone were used as controls. After culturing for 24, 48 and 72 h, real-time polymerase chain reaction (PCR) was performed to detect the expression of CTGF and TGF-β1 mRNA in LX-2 cells. Western-blot analysis was used to measure the expression of CTGF and TGF-β1 proteins in LX-2 cells.

RESULTS: After 24, 48, and 72 h, the expression of CTGF and TGF-β1 mRNA in LX-2 cells co-cultured with HepG2.2.15 were higher than those in the controls (CTGF: 1.7, 4.2, 9.6 times higher, P < 0.05; TGF-β1: 2.2, 6.1, 8.1 times higher, P < 0.01), and the most eminent effect was found at 72 h; however, CTGF and TGF-β1 mRNA expression in LX-2 cells co-cultured with HepG2 were 1.7, 1.2, 1.3 and 2.7, 1.9, 2.1 times higher than those in the controls (all P < 0.05). At the same time point, the protein expression of CTGF and TGF-β1 in LX-2 cells co-cultured with HepG2.2.15 (CTGF: 2.1, 2.6, 2.5 times higher, P < 0.05; TGF-β1: 1.7, 3.3, 3.1 times higher, P < 0.01) or HepG2 (CTGF: 1.6, 1.1, 0.9 times higher, P < 0.05; TGF-β1: 1.1, 1.4, 2.5 times higher, P < 0.05) were also higher than those in the control cells.

CONCLUSION: The expression of fibrosis-related factors in hepatic stellate cells are increased significantly after co-culturing with HepG2.2.15, which proves that HBV can induce fibrogenesis in vitro.