Selective IgA deficiency may be an under-recognized risk factor for severe COVID-19

Ameratunga R, Leung E, Woon ST, Lea E, Allan C, Chan L, Steele R, Lehnert K, Longhurst H. Selective IgA deficiency may be an under-recognized risk factor for severe COVID-19. J Allergy Clin Immunol Pract. 2022 Oct 11:S2213-2198(22)01043-1. doi: 10.1016/j.jaip.2022.10.002.

Abstract

SARS-CoV-2, the agent responsible for COVID-19, has caused havoc around the globe. Hundreds of millions of individuals have been infected and well over six million have died from COVID-19. Many COVID-19 survivors have ongoing physical and psychiatric morbidity, which will remain for the rest of their lives.
Early in the pandemic, it became apparent older individuals and those with comorbidities including obesity, diabetes mellitus, coronary artery disease, hypertension, renal and pulmonary disease were at increased risk of adverse outcomes. It is also clear that some immunodeficient patients, such as those with innate or T cell immune defects are at greater risk from COVID-19.
Selective IgA deficiency (sIgAD) is generally regarded as a mild disorder, where the majority of patients are asymptomatic because of redundancy in protective immune mechanisms. Recent data indicates patients with sIgAD may be at high risk of severe COVID-19. SARS-CoV-2 gains entry primarily through the upper respiratory tract mucosa, where IgA plays a critical protective role. This may underlie the vulnerability of sIgAD patients for adverse outcomes from COVID-19. This perspective highlights the need for ongoing research into mucosal immunity and improving COVID-19 treatments for patients with sIgAD.

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