Viral proteins, particularly Nef, may contribute to pulmonary vasculopathy as evident by the development of complex vascular lesions in Rhesus monkeys infected with simian immunodeficiency virus containing the nef gene.26 Another hypothesis is activation of adaptive immunity leading to immune cell migration and inflammation in the pulmonary vasculature.27 Another contribution might arise from behaviours that often accompany poor medication compliance (eg, smoking and drug and alcohol misuse) and increase the risk of cardiopulmonary disease generally. This evidence concerns the gene S100B and cor pulmonale.