Fig. 1

Hypothesis for how infections and autoimmune diseases may promote PAH in women and men. Infections and autoimmune diseases like HIV and systemic sclerosis (SSc) are able to cause inflammation, immune complex (IC) deposition, and remodeling in the lung that may lead to pulmonary arterial hypertension. Estrogen increases the risk of developing autoimmune diseases like SSc following infection or other insults by promoting antibody/autoantibody and IC deposition that may contribute to the increased incidence of PAH in women, especially for autoimmune diseases that affect the lung-like SSc. PAH associated with HIV infection occurs more often in men and HIV-associated PAH patients also have myocarditis. Inflammatory mechanisms that drive myocarditis in men following infection may also drive PAH