Immunoglobulin A (IgA) (IgA)

Immunoglobulin A (IgA) is the most abundant antibody class in human mucosal secretions and the second most prevalent in serum [1.4.1, 1.4.3]. It exists as two subclasses, IgA1 and IgA2, and plays a vital role in mucosal immunity by neutralizing pathogens and preventing their adherence to epithelial surfaces [1.1.1, 1.3.2]. In the circulation, monomeric IgA can induce anti-inflammatory signals through the FcαRI (CD89) receptor, while IgA immune complexes trigger pro-inflammatory responses [1.3.1, 1.3.5]. IgA is a primary therapeutic target in IgA nephropathy (Berger's disease), where abnormally glycosylated IgA1 (galactose-deficient IgA1) forms pathogenic immune complexes that deposit in the kidney mesangium, leading to inflammation and renal failure [1.2.1, 1.4.1]. Current therapeutic strategies focus on reducing IgA production by targeting B-cell survival factors such as APRIL and BAFF (e.g., sibeprenlimab, atacicept) or using targeted-release steroids like budesonide to suppress mucosal IgA synthesis [1.2.3, 1.2.5]. Additionally, IgA is being investigated as a therapeutic agent for passive immunization and cancer immunotherapy due to its ability to recruit myeloid effector cells [1.1.1, 1.3.5].

Other names

IgA1IgA2Secretory IgAsIgASerum IgAAlpha-chain antibody

Inhibition of B-cell survival factors (APRIL/BAFF) to reduce pathogenic IgA production, targeted mucosal immunosuppression in the ileum, complement pathway inhibition (Factor B and MASP-2), and depletion of IgA-secreting plasma cells [1.2.1, 1.2.3, 1.2.5].