Angiogenic Activity of Sera from Extrinsic Allergic Alveolitis Patients in Relation to Clinical, Radiological, and Functional Pulmonary Changes

Extrinsic allergic alveolitis (EAA) caused by inhaled organic environmental allergens can progress to a fibrotic end-stage lung disease. Neovascularization plays an important role in pathogenesis of pulmonary fibrosis. The aim of this study was to assess the effect of sera from EAA patients on the angiogenic capability of normal peripheral human mononuclear cells (MNC) in relation to the clinical, radiological, and functional changes. The study population consisted of 30 EAA patients and 16 healthy volunteers. Routine pulmonary function tests were undertaken using ERS standards. As an angiogenic test, leukocyte-induced angiogenesis assay according to Sidky and Auerbach was used. Compared with sera from healthy volunteers, sera from our EAA patients significantly stimulated angiogenesis (P < 0.001). However, sera from healthy donors also stimulated angiogenesis compared to PBS (P < 0.001). No correlation was found between serum angiogenic activity and clinical symptoms manifested by evaluated patients. A decrease in DLco and in lung compliance in EAA patients was observed but no significant correlation between pulmonary functional tests and serum angiogenic activity measured by the number of microvessels or an angiogenesis index was found. However, the proangiogenic effect of sera from EAA patients differed depending on the stage of the disease and was stronger in patients with fibrotic changes. The present study suggests that angiogenesis plays a role in the pathogenesis of EAA. It could be possible that the increase in the angiogenic activity of sera from EAA patients depends on the phase of the disease.