Autoreactive IgA antibodies are high prevalent and associated with clinical manifestations in systemic lupus erythematosus, systemic scleroderma and idiopathic inflammatory myositis

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Presentation Time: 11:30 AM - 12:45 PM
Poster Board Number: B617
Abstract ID: 4970

Presenting Author:
Quanzhen Li , Scientist at GeneCopoeia, Univ. of Texas Southwestern Med. Ctr.

Abstract:

Systemic lupus erythematosus (SLE), systemic scleroderma (SSc) and idiopathic inflammatory myositis (IIM) are autoimmune diseases characterized by a broad range of autoreactive antibodies (AutoAbs). In this study, we measured the serum IgA AutoAbs against 120 self-antigens in a cohort of 128 SLE, 73 SSc, 75 IIM and 140 healthy controls (HC), using OmicsArray™ antigen microarrays. We found IgA AutoAbs are highly prevalent in SLE and SSc compared with IIM and NC. 58.4% SLE and 41.7% SSc have 5 or more IgA AutoAbs compared with 16% in IIM and 14.1% in NC. 9 IgA AutoAbs most significantly elevated in SLE were anti-DNA antigens including dsDNA (54.7%), ssDNA (51.1%), and chromatin (46%). 32 IgA AutoAbs were significantly increased in SSC with highest reactivity to Scl-70 (55.6%). IIM showed lower IgA prevalence in general with highest in anti- Jo-1 (20%), anti-muscarinic receptor (8%) and anti-B2-microglubulin (6.7%). Significant correlation was observed between IgA and IgG isotypes on most AutoAbs. 3 IgA autoAbs (anit-gDNA, anti-C1q and anti-dsDNA) positively correlated with SLEDAI Score, but only anti-C1q was significantly elevated in lupus nephritis. 14 anti-nuclear IgA AutoAbs negatively correlated with serum complement C3 and/or C4 levels. Our study indicated that autoreactive IgA against nuclear components, in parallel with IgG, are highly prevalent in SLE and SSC patients. IgA AutoAbs could be used as biomarkers for diagnosis and prognosis of systemic autoimmune diseases.