IgA Antibodies and IgA Deficiency in SARS-CoV-2 Infection

A large repertoire of IgA is produced by B lymphocytes with T-independent and T-dependent mechanisms useful in defense against pathogenic microorganisms and to reduce immune activation. IgA is active against several pathogens, including rotavirus, poliovirus, influenza virus, and SARS-CoV-2. It protects the epithelial barriers from pathogens and modulates excessive immune responses in inflammatory diseases. An early SARS-CoV-2 specific humoral response is dominated by IgA antibodies responses greatly contributing to virus neutralization. The lack of anti-SARS-Cov-2 IgA and secretory IgA (sIgA) might represent a possible cause of COVID-19 severity, vaccine failure, and possible cause of prolonged viral shedding in patients with Primary Antibody Deficiencies, including patients with Selective IgA Deficiency. Differently from other primary antibody deficiency entities, Selective IgA Deficiency occurs in the vast majority of patients as an asymptomatic condition, and it is often an unrecognized, Studies are needed to clarify the open questions raised by possible consequences of a lack of an IgA response to SARS-CoV-2.

Automated summary

IgA plays a crucial role in defense against pathogens, especially in the context of specific antibody responses to SARS-CoV-2 which may impact the severity of COVID-19 and vaccine efficacy.