FAS and lymphopenia: Lymphopenia is mediated by the overmentioned inflammatory cytokine milieu (especially rich in IL-6, IL-10, and TNF-α) (42), via lymphocyte sequestration into lymphoid tissue and endothelia by IFN-I and TNF-α (43, 44) or by extensive cell death triggered by IL-6 and Fas-FasLigand signaling (34).