Regulation of erythropoietin production in a case of congenital erythropoietin-dependent pure erythrocytosis.
In a patient with congenital erythropoietin-dependent pure erythrocytosis (EDPE) associated with hypersensitivity of erythroid progenitor cells to erythropoietin (Epo), the investigations planned to elucidate the mechanism responsible for hormone hyperproduction revealed that Epo synthesis was (1) independent of normal oxygen-mediated feedback induced by phlebotomy; (2) not modulated by adenosine as a second messenger (the treatment with the adenosine antagonist theophylline in fact left unchanged the serum Epo levels); and (3) uninfluenced by iron therapy. The Epo dose-response curve for growth of erythroid progenitor was similar to that of three age-matched thalassemia patients with increased serum Epo levels, (sEpo) suggesting that the observed erythroid progenitors hypersensitivity to Epo could represent an ex vivo artifact induced by the increased sEpo levels.
Department of Pediatrics, University of Verona, IRCCS Policlinico S. Matteo, Pavia, Italy.
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Borgna-Pignatti
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Liberato
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Marradi
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V
Rosti
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Barosi
D001815:Bloodletting; D002478:Cells, Cultured; D015672:Erythroid Precursor Cells / Q000187:drug effects / Q000473:pathology; D004921:Erythropoietin / Q000096:biosynthesis* / Q000627:therapeutic use; D006801:Humans; D007223:Infant; D007501:Iron / Q000627:therapeutic use; D008297:Male; D011086:Polycythemia / Q000151:congenital* / Q000378:metabolism* / Q000628:therapy; D011994:Recombinant Proteins; D013806:Theophylline / Q000627:therapeutic use
D011994:Recombinant Proteins; D004921:Erythropoietin; D013806:Theophylline; D007501:Iron