Increased serum interleukin 6 levels in patients with myelodysplastic syndromes.

Serum concentration of interleukin 6 (IL-6) was measured in 45 patients with myelodysplastic syndromes (MDS). A commercially available enzyme-linked immunosorbent assay (ELISA) with a sensitivity of 3 pg/ml was used. While IL-6 was undetectable in healthy volunteers, 32 of the patients with MDS showed IL-6 concentrations higher than 3 pg/ml. In MDS we found serum concentrations of IL-6 between 0 and 150 pg/ml with a median of 9 pg/ml, mean and standard deviation (SD) were 15 and 26 pg/ml respectively. In refractory anemia with excess of blasts in transformation (RAEB-t) the serum IL-6 concentrations were significantly higher than in refractory anemia (RA; p = 0.0025), in refractory anemia with excess of blasts (RAEB; p = 0.0050) and in chronic myelomonocytic leukemia (CMML; 0.0449). No significant difference was detected between RA and RAEB or between CMML and the other types of MDS, while s significant negative correlation was found between the concentrations of IL-6 and hemoglobin (p = 0.0228).