IgA Vasculitis: Etiology, Treatment, Biomarkers and Epigenetic Changes

Abstract

IgA, previously called Henoch-Schönlein vasculitis, is an essential immune component that drives the host immune response to the external environment. As IgA has the unique characteristic of a flexible response to broad types of microorganisms, it sometimes causes an autoreactive response in the host human body. IgA vasculitis and related organ dysfunction are representative IgA-mediated autoimmune diseases; bacterial and viral infections often trigger IgA vasculitis. Recent drug developments and the presence of COVID-19 have revealed that these agents can also trigger IgA vasculitis. These findings provide a novel understanding of the pathogenesis of IgA vasculitis. In this review, we focus on the characteristics of IgA and symptoms of IgA vasculitis and other organ dysfunction. We also mention the therapeutic approach, biomarkers, novel triggers for IgA vasculitis, and epigenetic modifications in patients with IgA vasculitis.

Keywords: IgA vasculitis; biomarker; epigenetic changes; treatment.

Figure 1

The structure of IgA1 and IgA2. IgA1 has an O-linked glycosylation rich structure in the hinge with 13 amino acids extension in the hinge region longer than IgA2. IgA consists of two heavy chains and light chains that organize Fab regions with the domains of Cα1, VH1, VL, and CL, and are responsible for antigen recognition. Cα1 is a unique component in IgA. The Fc region consists of two Cα2 and Cα3 domains, namely J chain, which bind to another IgA of the J chain to make a dimer immune complex.