Multiplexed analysis of circulating IgA antibodies for SARS‐CoV‐2 and common respiratory pathogens in COVID‐19 patients

Previous studies have revealed a diagnostic role of pathogen‐specific IgA in respiratory infections. However, co‐detection of serum specific IgA for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and common respiratory pathogens remains largely unexplored. This study utilizes a protein microarray technology for simultaneous and quantitative measurements of specific IgAs for eight different respiratory pathogens including adenovirus, respiratory syncytial virus, influenza virus type A, influenza virus type B, parainfluenza virus, mycoplasma pneumoniae, chlamydia pneumoniae, and SARS‐CoV‐2 in serum sample of patients with coronavirus disease 2019 (COVID‐19). A total of 42 patients with COVID‐19 were included and categorized into severe cases (20 cases) and nonsevere cases (22 cases). The results showed that co‐detection rate of specific‐IgA for SARS‐CoV‐2 with at least one pathogen were significantly higher in severe cases than that of nonsevere cases (72.2% vs. 46.2%, p = .014). Our study indicates that co‐detection of IgA antibodies for respiratory pathogens might provide diagnostic value for the clinics and also be informative for risk stratification and disease management in patients with COVID‐19.