Clinical significance of early IgA anti-SARS-CoV-2 antibody detection in patients from a Romanian referral COVID-19 hospital

Controlling the spread of coronavirus disease 2019 (COVID-19) includes institute isolation, quarantine measures and appropriate clinical management, which all require effective screening, diagnostic and prognostic tools. The present study aimed to analyze severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific immunoglobulin (Ig)A detection and determine the potential association with the clinical course of COVID-19 and the levels of inflammation. In the present study, the presence of IgA and IgG SARS-CoV-2 antibodies in 75 consecutive patients with confirmed COVID-19 infection was investigated. No significant differences were found between the IgA positive and negative groups, regarding the presence of symptoms, haematological and inflammatory variables, or the presence of pneumonia. In the majority of cases, antibody detection was comparable, for example, 79.7% of patients in the IgA positive group exhibited both types of antibodies, while 80.9% of patients in the IgA negative group were also IgG negative. A total of four patients in the IgA negative group presented with anti-SARS-CoV-2 IgG antibodies. Early detection of IgA was more frequent in patients who later developed severe forms of the disease. In addition, the IgG SARS-CoV-2 antibody response was higher in patients with the severe form of the disease.