TNFSF10 and lymphopenia: Previous studies conducted on SARS-CoV-1, revealed that no modulation of TLR was observed in monocytes but the infection was associated with over-expression of chemokine receptors CCR-1, CCR-3, and CCR-5 and TNF-related apoptosis inducing ligand (TRAIL) which may induce lymphocytes apoptosis and lymphopenia (117).