Evaluation of classical and novel autoantibodies for the diagnosis of Primary Biliary Cholangitis-Autoimmune Hepatitis Overlap Syndrome (PBC-AIH OS)

Abstract

Background and aimsUp to 20% of Primary Biliary Cholangitis (PBC) patients are estimated to have features that overlap with Autoimmune Hepatitis (AIH). Patients with PBC-AIH overlap syndrome (PBC-AIH OS) have been reported to exhibit suboptimal responses to ursodeoxycholic acid therapy, and are more likely to progress to cirrhosis. Anti-double stranded DNA (anti-dsDNA) and anti-p53 have been previously suggested to be potential autoantibodies for identifying patients with PBC-AIH OS. In our well defined PBC patient cohorts, a comprehensive assessment of various classical and novel autoantibodies was evaluated for their utility in identifying PBC-AIH OS patients.MethodsPBC-AIH OS was classified according to the Paris criteria and PBC as per the European Association for the Study of the Liver guidelines. Biobanked serum samples from 197 patients at the University of Calgary Liver Unit and the University of Alberta were analyzed for classical and novel autoantibodies. Anti-dsDNA was measured by the Crithidia luciliae immunofluorescence (CLIFT) assay (1:20 dilution) and chemiluminescence (CIA: QUANTA Flash®, Inova Diagnostics, San Diego). Anti-p53, anti-Ro52/TRIM21, anti-YB 1, anti-GW182, anti-Ge-1, and anti-Ago 2 were measured by either an addressable laser bead immunoassay (ALBIA) or line immunoassay (LIA). Autoantibodies against MIT3, gp210, sp100, LKM1, SLA, and the novel autoantibodies Hexokinase-1 (HK-1), and Kelch like protein 12 (KLHL-12) were measured using QUANTA Lite® ELISA assays. We applied non-parametric methods to compare the biomarkers frequencies between study groups. We used multivariate adjusted models and AUROC to compare the diagnostic accuracy of the different autoantibodies alone or in combination with serum biochemistry.Results16 out of 197 PBC patients (8.1%) were classified as PBC-AIH OS. Compared to PBC patients, PBC-AIH OS patients were similar in age (median: 59 vs. 63, P = 0.21) and female predominance (94% vs. 89%, P = 1.00). Anti-dsDNA-by CLIFT (37.5% in PBC-AIH OS vs 9.9% in PBC alone, P <0.01) was the only autoantibody associated with PBC-AIH OS; a finding consistent with previous reports. Significant elevation in serum ALT (62 IU/L in PBC-AIH OS vs 37 IU/L in PBC alone, P < 0.01), and serum IgG (17.6 g/L in OS vs 12.1 g/L in PBC alone, P <0.01) were observed in patients with PBC-AIH OS receiving medical/immunosuppressive therapy. In a multivariate model, positive anti-dsDNA by CLIFT, ALT and IgG were significant predictors of PBC-AIH OS with an area under the receiver operator curve (AUROC) value of 0.84.ConclusionsConsistent with previous findings, the presence of anti-dsDNA by CLIFT is associated with PBC-AIH OS. Contrary to previous reports, anti-p53 was not associated with PBC-AIH OS. Our comprehensive evaluation of various classical and novel autoantibody biomarkers including Ro52/TRIM21, anti-p53, anti-KLHL-12 and anti-HK-1 were not significantly associated with PBC-AIH OS. Our findings highlight the ongoing need for the research and development of new autoantibody biomarkers ...

Establishment of international autoantibody reference standards for the detection of autoantibodies directed against PML bodies, GW bodies, and NuMA protein

“…Interestingly, anti-KLHL 7 and anti-HK1 were also demonstrated in MND-REF by IP-MS. KLHL 7 is one of the 42 KLHL family members composed of a BTB/POZ domain, a BACK domain, and 5-6 Kelch motifs [48]. In the KLHL family, autoantibodies to KLHL 7 and 12 have been reported to be associated with autoimmune diseases, including PBC [49][50][51]. Uchida K et al identified these two KLHL proteins as novel autoantigens in SjS by phage-display cloning [49].…”

“…HK1 is a mitochondrial enzyme that regulates crucial cellular processes [52]. Anti-HK1 and anti-KLHL 12 have been reported as novel biomarkers for PBC patients [49,51,53], although their specificity to PBC have not been validated [50]. Cytoplasmic discrete dots/GWB-like pattern (AC-18) are associated with antibodies to GW182, Ge-1, and Su/ Ago2.…”

Unmet needs in autoimmune liver diseases

“…PBC is an autoimmune liver disease in which an autoantibody to the pyruvate dehydrogenase complex of mitochondria leads to damage to the bile ducts . This abnormality can be detected in up to 95% of patients with PBC . Like many other autoimmune diseases, PBC predominantly affects women.…”

“…Autoimmune liver diseases consist of autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis, juvenile autoimmune hepatitis and variant syndromes . Although a growing body of evidence indicates that individuals with particular genetic backgrounds may develop autoimmune liver diseases with accumulating environmental triggers, the pathogenesis behind these conditions is still incompletely elucidated .…”

Autoantibody Formation and Mapping of Immunogenic Epitopes against Cold-Shock-Protein YB-1 in Cancer Patients and Healthy Controls

“…A review of the literature reveals that autoantibodies targeting YB-1 protein have been described in patients diagnosed with autoimmune diseases such as systemic sclerosis, primary biliary cholangitis autoimmune hepatitis (PBC-AIH) as well as autism spectrum disorders [15][16][17]. Jeoung et al applied recombinant GST-YB-1 to determine autoantibody frequency in rheumatic diseases, with systemic sclerosis showing the highest prevalence (44%) followed by SLE (14%), whereas healthy controls mostly had no autoantibodies (7%).…”