PLATELETS MODULATES CD4+ T CELL FUNCTION IN COVID-19 THROUGH A PD-L1 DEPENDENT MECHANISM

A. PALETTA; F. DI DIEGO GARCÍA; A. VARESE; F. ERRA DÍAZ; J. GARCÍA; J.C. CISNEROS; G. LUDUEÑA; I. MAZZITELLI; A. PISAREVSKY; G. CABRERIZO; A. LOPEZ MALIZIA; A.G. RODRIGUEZ; N. LISTA; Y. LONGUEIRA; J. SABATTÉ; J. GEFFNER; F. REMES LENICOV; A. CEBALLOS

Conferencia; Reunión de Sociedades de Biociencias 2021; 2021

SAIC - SAFICI -SAI

Severe COVID-19 is associated with a systemic inflammatory response and a progressive CD4+ T cell lymphopenia and dysfunction. Here, we analyzed whether platelets might contribute to CD4+T cell dysfunction in COVID19.Blood samples were obtained from healthy donors (HD) n=30 or COVID19 patients, n=60. Patients were classified into mild, moderate and severe according to WHO criteria. Each participant provided written informed consent. Oncologic and vaccinated patients were excluded from the study. Proportion of CD4+T Cells?platelets aggregates was measured by flow cytometry (CD4+CD62p+ cells). CD4+T cells were isolated from HD and cultured with platelets from a single HD or a COVID19 patient (1:100 ratio). CD25 was evaluated by flow cytometry and cytokine production was measured by ELISA.We observed a high frequency of CD4+ T cell-platelet aggregates in COVID19 (n=30-60, p