Serum levels of erythropoietin and selected other cytokines in patients with anemia of chronic disease.

Serum levels of erythropoietin and five other cytokines potentially operational in erythropoiesis were determined in patients with anemia of chronic disease. No correlation between erythropoietin levels and severity of anemia was found. A spectrum of abnormality was encountered among patients in whom there was less than expected erythropoietin response to increased levels of erythropoietin and among others in whom the erythropoietin levels were subnormal for their degree of anemia. Increased serum levels of interleukin-3, granulocyte colony-stimulating factor, and granulocyte-macrophage colony-stimulating factor were encountered in limited numbers of patients, especially those with increased erythropoietin levels. Deficient erythropoietin production is concluded to be the major cause of anemia of chronic disease.