PO:02:035 Beyond diagnosis: blood immunoprofiling reveals molecular subgroups and drug candidates in systemic autoimmune disease patients

Objectives Sjogren's Syndrome (SjS), an autoimmune disorder marked by lymphocyte infiltration causing xerophthalmia and xerostomia, is classified into primary Sjogren's syndrome (pSjS) and secondary Sjogren's syndrome (sSjS).The ACR/EULAR 2016 criteria currently rely on anti-Ro/SSA antibodies, exhibiting a 50-70% positivity rate in patients with SjS.This study seeks to pinpoint a high-positivity autoantibody as a diagnostic biomarker of SjS.Methods Through protein microarray analysis, anti-lysosomal protein transmembrane 4 alpha (LAPTM4A) was identified as a potential biomarker of SS.Using the Baculovirus Expression Vector System, GST-fused LAPTM4A was generated.Enzymelinked immunosorbent assay measured anti-LAPTM4A antibody titers in pSS (n=46), sSS (n=36), total SS (tSS, n=82), and normal controls (NCs, n=30).T-test analysis assessed and the positivity rate was calculated.Results Anti-LAPTM4A exhibited a substantial 67% positivity in pSjS via protein microarray analysis.ELISA measured anti-LAPTM4A antibody titers: pSjS (48.1 arbitrary unit(AU)), sSjS (47.54 AU), tSjS (47.85 AU), and NCs (36.02 AU).Anti-LAPTM4A antibody detection was notably elevated in pSjS, sSjS and tSjS (p<0.05).The positivity rates for anti-LAPT-M4A antibody in patients negative for the anti-Ro antibody were 30%, 48%, and 43% in pSjS, sSjS, and tSjS groups, respectively.Conclusions This study aimed to evaluate the potential of the anti-LAPTM4A antibody as an additional biomarker for SjS.Elevated anti-LAPTM4A antibody titers observed in pSjS, sSjS, and tSjS compared to NCs indicate its promise as a supplementary diagnostic biomarker for SjS.