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 either absent or much lower than is seen in chronic obstructive pulmonary disease (COPD) with comparable hypoxemia. This study investigates the differences in erythropoiesis between IPF and COPD, searching for the possible underlying mechanisms.


METHODS
The study included 32 patients with COPD, 18 patients with IPF, all with overt hypoxemia (PO(2) <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 from 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 IPF. 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.
Tsantes
Argirios
A
Laboratory of Haematology, G. Gennimatas General Hospital of Athens, Athens, Greece.
Bonovas
Stefanos
S
Tassiopoulos
Stergios
S
Filioussi
Kalitsa
K
Vlachou
Athina
A
Meletis
John
J
Papadhimitriou
Stefanos
S
Vaiopoulos
George
G
D000368:Aged; D001784:Blood Gas Analysis; D004906:Erythrocyte Count; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000473:pathology / Q000502:physiology; D004920:Erythropoiesis / Q000502:physiology*; D004921:Erythropoietin / Q000097:blood*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000503:physiopathology*; D011658:Pulmonary Fibrosis / Q000097:blood / Q000503:physiopathology*
D006454:Hemoglobins; D004921:Erythropoietin