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

PALLARÉS, HORACIO M.; DI DIEGO GARCIA, FACUNDO; VARESE, A.; ERRA DIAZ, FERNANDO; GARCIA J; CISNEROS, JUAN CARLOS; LUDUEÑA, GUILLERMINA; MAZZITELLI, IGNACIO; PISAREVSKY, ANDREA; CABRERIZO, GONZALO; A. LOPEZ MALIZIA; RODRIGUEZ, ALEJANDRA G.; LISTA, NICOLÁS; LONGUEIRA, YESICA; SABATTÉ, JUAN; GEFFNER, J.; REMES LENICOV, FEDERICO; CEBALLOS, ANA

Virtual

Congreso; Reunión Conjunta SAIC. SAI. AAFE. NANOMED-AR 2021; 2021

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 pro- vided 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