Genetics and immunogenetic aspects of primary pulmonary hypertension.

Primary pulmonary hypertension (PPH), also referred to as unexplained or idiopathic pulmonary hypertension, is the clinical term used to describe a condition in patients for which we can find no underlying cause. Patients with PPH not uncommonly also have evidence of immune dysregulation: autoimmune disorders, drug therapy, or HIV infections. We will review these associations and possible relevant abnormalities in immune regulation with regard to how they may play a role in the pathogenesis of PPH. Autoantibody-HLA correlations have been observed in several subsets of PPH patients. In addition, a familial form of PPH has been described and characterized with linkage to chromosome 2q31-q32. The identification of a specific gene for PPH and the subsequent understanding of its effects will help us identify the basic cause of PPH. Furthering our understanding regarding the role(s) and significance of immunogenetic as well as genetic aspects of the pathogenesis and pathophysiology of PPH should also lead to improved therapeutic modalities for PPH.