Assessment of Serum Levels of Immunoglobulin A (IgA) Class in Patients with COVID-19 and Asthma

Background: Growing interest in the importance of the mucosal immune system, coupled with an improved understanding of the functional properties of IgA has re-engineered interest in this previously neglected immunoglobulin class. Research into IgA roles and levels might open a novel approach in therapeutic settings and mucosal vaccination. Both COVID-19 and asthma are broncho-mucosal inflammatory diseases. However, the exact role or levels of IgA during the pathogenesis of these diseases is unclear.

Objective: To investigate the levels of IgA as a potential differentiating biomarker of patients with COVID-9 or asthma from controls.

Methodology: Serum IgA levels were measured in 30 patients with bronchial asthma and 30 COVID-19 patients with their 30 corresponding age- and sex-matched healthy control subjects using enzyme-linked immunosorbent assay.

Results: The mean value of serum IgA was significantly increased in COVID-19 patients at admission (p=0.001) or COVID-19 patients at discharge (p=0.031) compared with the level in corresponding control. The mean value of serum IgA was similar in COVID-19 patients at admission compared with COVID-19 patients at discharge. The mean values of serum IgA were not significantly higher in COVID-19 patients at admission and COVID-19 patients at discharge compared with asthma patients (p>0.50). The mean value of plasma IgA was significantly decreased (p=0.018) in asthma patients compared with the level in corresponding control.

Conclusions: Serum IgA could be a useful biomarker to differentiate patients with COVID-9 or patients with asthma from un-infected controls.