Serum erythropoietin and reticulocyte counts in inflammatory process.

The role of erythropoietin in the pathogenesis of anaemia associated with inflammatory disorders is unclear. We studied serum erythropoietin levels in patients with inflammatory process of varying aetiologies. Serum erythropoietin levels and reticulocyte counts were prospectively measured in 40 patients with inflammatory syndromes and compared with values obtained in 20 patients with myelodysplastic syndromes. Significant inverse correlation between erythropoietin levels and haemoglobin concentration were noted in the 2 groups. The slope of the regression line for patients with inflammatory disorders was lower as compared with that for the myelodysplastic syndromes. In all cases, when the erythropoietin response in relation to degree of anaemia is compared with that which occurs in patients with myelodysplastic syndromes, the inadequate erythropoietin response in patients with chronic inflammatory process becomes evident. In patients with inflammatory process, a relationship between erythropoietin levels and reticulocyte counts were only noted in patients with mildly anaemia (haemoglobin concentration higher than 10.5 g/dl). This study suggests blunted erythropoietin production and impaired marrow response to this hormone in the anaemia which occurs in inflammatory syndromes and supports the hypothesis that these disorders may contribute to the development of the anaemia associated with inflammatory disorders.