IL-6, IL-8, IL-10 and TNF-α were present in similar concentrations in SARS infected patients and may potentially cause SARS-associated ARDS. Similarly, VEGFA is the key regulator of vascular permeability, hence called as “vascular permeability factor”. High VEGF expression allows the pulmonary vascular albumin extravasation which leads to the vascular permeability, causing pulmonary oedema. Furthermore, Nitric Oxide (NO) (NOS3) has been observed to inhibit the viral replication during early stages which reduces the chances of spread of virus giving ample time to the immune system for recovery. KNG has a role in contact activation of blood coagulation. The histidine rich domain of high molecular weight KNG (HMW-KNG) releases bradykinin which helps in the release of anti-microbial peptides.