ABSTRACT
Medical conditions like pneumonia, severe acute respiratory distress syndrome, myocarditis, thrombosis, and cytokine storm resulting from underlying uncontrolled inflammatory processes are linked to increased severity of COVID-19. It is known that T lymphocytes play a central role in the regulation of the body's inflammatory response and provide protection from viral infections. Cathelicidins, are antimicrobial peptides that destroy viruses by cleaving viral envelope proteins through proteolysis. Cathelicidins also help in the stimulation of macrophages. Cathelicidins increase vascular permeability at the site of infection and cause more macrophages to infiltrate into the area where the pathogen is and subsequently activate the proliferation and recruitment of macrophages. Low vitamin D leads to decreased synthesis of antimicrobial proteins like ß-defensins and cathelicidins. Decreased ß-defensins leads to decreased attacks on the viral envelope and consequently the decreased destruction of the virus. The immunotherapeutic effect of vitamin D on ACE-2–angiotensin cascade is an important aspect to consider.
