Deciphering a Specific Signature of the Immunosenescence Induced in COVID-19+ Patients Versus Rheumatoid Arthritis Patients

Immune aging or immunosenescence is characterized by a loss of T cell clonal diversity and a contraction of naïve T cells with proliferative capacity associated with the functional impairment of many others immune cells as well as a chronic low degree of inflammation. A restrictive T cell repertoire is likely more prone to antigen-mediated exhaustion observed during chronic viral infections. Notably, lymphopenia is the most consistent laboratory abnormality in COVID-19 infected patients and both lung-resident and circulating T cells potently up-regulate markers of T cell exhaustion. It is not clear today if the association of COVID-19 disease severity with age is mainly related with the immunosenescence of infected patients. Interestingly, T cell exhaustion and premature immunosenescence have also been observed in chronic inflammatory diseases such as rheumatoid arthritis (RA). To better understand the immunological mechanisms involved in SARS-Cov-2 pathophysiology, the investigators propose to compare the immunosenescence patterns observed during RA, aging and SARS-Cov-2 infected patients in order to design improved therapeutic interventions.