Changes in the gene expression of activation-induced cytidine deaminase in peripheral blood mononuclear cells in COVID-19 patients

Objective: To assess the changes in gene expression of activation- induced cytidine deaminase (AID) in COVID-19 patients and its relationship with the presence of autoantibodies in those ones. Methods: This retrospective study was carried out among COVID-19 patients’ serum and peripheral blood mononuclear cells that were archived at the main COVID-19 referral centers in Iran from January to March 2022. The titer of autoantibodies in the serum of healthy and COVID-19 subjects was investigated by serological tests. Then, the AID gene expression in peripheral blood mononuclear cells in two groups was evaluated using the real-time polymerase chain reaction method. Results: 100 patients were included. In total, 8% and 1% of patients had a significant titer of anti-citruhinated protein antibody and antinuclear antibody autoantibodies, respectively, and those suffered from at least one comorbidity. No patient was positive for antiphospholipid autoantibody. Moreover, no significant changes were observed in the titer of autoantibodies between healthy subjects and patients. Furthermore, the increase in the expression of the AID gene was not significant in two groups. Conclusions: The presence of autoantibodies in COVID-19 patients might be linked to the previous underlying disease.