Research Advances and Biological Features of IgA for Immune-Related Diseases.

As the predominant antibody isotype at human mucosal surfaces, immunoglobulin A (IgA) exerts critical functions in mucosal defense and systemic immune homeostasis. The two IgA subclasses, IgA1 and IgA2, possess distinct structural and functional features and assemble into dimeric IgA (dIgA) and secretory IgA (sIgA) under physiological conditions. With advances in cryo-electron microscopy, the molecular architecture and assembly of sIgA have been clearly characterized. While IgA protects hosts from pathogenic infection and sustains immune balance, aberrantly altered IgA contributes to the pathogenesis of IgA nephropathy and autoimmune encephalitis. To date, IgA-based therapeutics have displayed promising therapeutic efficacy against respiratory disorders, inflammatory bowel diseases and oral fungal infections. Through standardized retrieval and categorical sorting of the published literature covering IgA structure, physiological functions, disease pathogenic mechanisms and therapeutic research, this review systematically organizes relevant research advances, analyzes the bottlenecks and translational prospects of IgA-targeted therapeutics, and provides objective references to accelerate the clinical translation of IgA antibody agents.