Investigation of the Contribution of Autoantibodies to Clinical Diagnosis in Liver Pathologies and the Identification of Accompanying Autoimmune Diseases

Abstract

Autoantibodies are frequently detected in the presence of autoimmune liver diseases (ALD) [autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC)] and are widely used to classify the disease clinically. The aim of this study was to investigate the contribution of autoantibodies for the diagnosis of ALD and the identification of other accompanying systemic autoimmune rheumatic diseases (SARD). In addition, it was aimed to compare the results of indirect immunofluorescence (IIF) antinuclear antibody (ANA) patterns and extractable nuclear antigen (ENA) antibodies. A total of 593 patients, including 544 patients with high liver function tests from general surgery/gastroenterology clinics and 49 patients referred from internal medicine/rheumatology clinics to investigate ALD, were included in the study. HBsAg and anti-HCV test results of the patients were found to be negative. ANA, anti-mitochondrial antibody (AMA)/anti-liver-kidney microsomal antibody (LKM), anti-smooth muscle antibody (ASMA), antineutrophil cytoplasmic antibody (ANCA) assays were performed by indirect immunofluorescence method (IIF) (Euroimmune AG, Luebeck, Germany). Extractable nuclear antigen (ENA) (nRNP/Sm, Sm, SS-A, SS-B, Scl-70, Jo-1, dsDNA, nucleosome, histone, ribosomal P-protein, AMA-M2, Ro-52, PM-Scl, CENP-B, PCNA, DFS70) and liver profiles [soluble liver antigen\liver pancreas antigen (SLA/LP), liver cytosolic antigen-1(LC-1), LKM-1, anti-mitochondrial antibody M2(AMA-M2)] (Euroimmune AG, Luebeck, Germany) were detected by immunoblot (IB) method. Demographic characteristics, clinical data, presence of systemic autoimmune rheumatic diseases (SARD), radiological and laboratory findings were determined from the medical records. Autoantibody tests were found to be negative in 461 (77.7%) of 593 patients (mean age= 53.3 ± 15.6, age range= 18-90), and were positive in 132 (22.3%) (86.4% female) of the patients. Of the patients with positive autoantibodies, 60.6% (80/132) were diagnosed as PBS and 1.5% (2/132) were diagnosed as AIH (positive anti-LC-1 and anti-LKM1 antibodies). Fourteen of the patients (10.6%) with centromere, nuclear membrane (NM), multiple nuclear dot (MND) staining patterns and elevated liver enzymes could not be diagnosed as a specific disease and were followed up. PBS (13/30) was detected in approximately half of the patients diagnosed with SARD. The most common accompanying SARD in PBC patients was Sjögren’s syndrome (SS) (7.5%, 6/80), followed by rheumatoid arthritis (RA) (5.0%, 4/80), scleroderma (2.5%, 2/80), and systemic lupus erythematosus (SLE) (1.3%, 1/80) respectively. The most common pattern was the AMA staining pattern (34.8%, 46/132) among the autoantibody positive patients. AMA and ANA staining patterns were detected together in 31.1% (41/132) of the patients. In the ENA profile results of these patients, the most common profile detected was anti-Ro-52 (65.9%, 27/41), followed by anti-SSA (34.1%, 14/41), anti-SSB (22.0%, 9/41) and anti-CENP-B (12.2%, 5/41) autoantibodies, respectively. ANA patterns were detected in 32.6% (43/132) of the patients (NM 9.1%, centromere 9.1%, MND 6.8%, respectively). In our study, 87.5% (70/80) of the patients diagnosed as PBS were found to have AMA positivity and 12.5% (10/80) of them had ANA positivity (such as NM, CNN, centromere). The characteristics, laboratory and radiological findings of the patients with isolated AMA positivity alone (Group 1) and patients with multiple patterns/autoantibodies (Group 2) were compared. In patients with multiple patterns/autoantibodies (Group 2), the presence of cirrhosis and liver heterogeneity were found to be higher than Group 1 (p= 0.049). ALD associated autoantibodies can be detected before years from the clinical disease. ALD may be associated with various SARD. Detection of ALD-related autoantibodies in patients diagnosed with SARD can provide early diagnosis of these patients. These autoantibodies guide both diagnosis and prognosis as in PBC. Collaboration between the laboratory specialist and the clinician is critical in the diagnosis, management and early recognition of these patients before clinical disease.