Findings of inflammatory infiltrates in vascular lesions of lungs displaying pulmonary arterial hypertension (PAH) emphasize the possible influence of inflammatory mechanisms under this condition. Chemokine RANTES and chemokine fractalkine are known to
be important chemoattractants for monocytes and T-cells. We hypothesize that both chemokines could promote leucocytic recruitment in lungs of patients with PAH. The study demonstrates elevated expression of RANTES and fractalkine mRNA, as well as protein
product in lung samples from PAH-patients as compared to controls, using RT-PCR, in situ hybridization, and immunohistochemistry. Our experiments provide evidence for increased RANTES and fractalkine production in lungs of
patients suffering from severe PAH. They support the concept that inflammatory mechanisms play a role in the natural history of PAH.