A comparative study of the role of erythropoietin in the pathogenesis of deficient erythropoiesis in idiopathic pulmonary fibrosis as opposed to chronic obstructive pulmonary disease.

Background:Despite the severe derangement of gas exchange in the advanced stages of idiopathic pulmonary fibrosis (IPF), secondary erythrocytosis is eitlier absent or much lower than is seen in chronic obstrtictive pulmonary disease (COPD) with comparable hypoxemia. This study investigates the differences in erythropoiesis between IPF and COPD, searching for the possible underlying mechanisms. Material/Methods: The study included 32 patients with COPD, 18 patients with IPF, all with overt hypoxemia (PO2 < 65 mmHg), and 34 healthy controls. Erythrocytic parameters and serum erythropoietin (EPO) levels were assessed for all subjects. In a number of patients from both groups, the development of erythroid colonies grown front peripheral blood mononuclear cells was assayed in semisolid methylcellulose cultures and compared to cultures of control cells, in the presence of patient or control serum. Results: Hb and serum EPO levels Were significantly higher in the COPD group than in IPF patients and controls. However, the number of BFU-E colonies obtained from mononuclear cells of IPF patients was clearly higher than in COPD patients when the same culture medium was used. Unlike COPD sera, IPF sera induced a significant growth inhibition of erythroid bursts arising from mononuclear cells of both patients and controls. Conclusions: Our findings suggest a kind of ineffective erythropoiesis in IPE Defective EPO production and inhibitory effect on erythropoiesis exerted by pro-inflammatory cytokines released from alveolar macrophages may be implicated in the suboptimal erythropoietic response. However, the possible involvement of other factors affecting erythropoiesis in IPF requires further investigation.