Lymphocyte Populations and Autoantibodies, in a Cohort of Patients with Rheumatoid Arthritis: A Long-Term Study of Covid-19 Cases and Non-Covid-19 Controls

ABSTRACT

Objectives: To assess the immunological [Lymphocyte populations (LP) and Autoantibodies (Ab)] and clinical profile of rheumatoid arthritis (RA) patients who suffered from COVID-19 compared with non-COVID-19 RA patients. Method(s) A nested case-control study of RA patients treated under a strict follow-up model. RA patients and confirmed COVID-19 infection (last 24 months) and RA patients without the infection were included. Subgroups of cases Long COVID (LC) symptoms after infection for >=4 weeks;Post COVID syndrome (PCS) symptoms for >=12 weeks;and patients with symptoms alpha4 weeks. Sociodemographic, clinical, and paraclinical variables of RA and COVID-19 infection (in cases) were captured. Antinuclear antibodies (ANA), anticardiolipin antibodies, lymphocyte populations (BD FACSDuetTM-BDFACSLyricTMmultiparameter flow cytometry) T cells, B cells, and NK were evaluated. Univariate and bivariate analyzes (STATA 17) were done. Result(s) 300 patients were included (148 cases/152 controls;87.3% women). Median age 59 years (IQR 11). 71.86% were in low disease activity. There were no significant differences in sociodemographic and clinical characteristics between cases and controls. Cases had a time since infection of 18.5 months (IQR 7). Of the total cases, 69%presented LC and 63%PCS.No significant differences were found between cases and controls in the lymphocyte population nor in the antibodies evaluated. There were no differences in the immune profile when comparing patients with LC and PCS with those with symptoms alpha4 weeks after COVID-19 infection. Conclusion(s) No differences were found in the behavior of the immunological profile (independent of symptoms of LC and PCS) in RA patients under strict follow up, evaluated long-term after infection with those who did not have COVID-19. This suggest that patients returned to their baseline homeostatic state, something that has not yet been reported up to now. These results should be replicated in populations with different RA characteristics.