Interleukin-6 and interleukin-10 levels in chronic lymphocytic leukemia: correlation with phenotypic characteristics and outcome

The objective of this study was to examine the correlation between serum in terleukin-g (IL-6) and IL-10 levels and outcome in chronic lymphocytic leuk emia (CLL), Serum IL-6 and IL-10 levels were measured by enzyme-linked immu noabsorbent assays from 159 and 151 CLL patients, respectively, and from he althy control subjects (n = 55 [IL-6]; n = 37 [IL-10]). Cytokine levels wer e correlated with clinical features and survival. Serum IL-6 levels were hi gher in CLL patients (median, 1.45 pg/mL; range, undetectable to 110 pg/mL) than in control subjects (median, undetectable; range, undetectable to 4.3 0 pg/mL) (P < .0001), Serum IL-10 levels were higher in CLL patients (media n, 5.04 pg/mL; range, undetectable to 74 pg/mL) than in normal volunteers ( median, undetectable; range, undetectable to 13.68 pg/mL) (P < .00001), Ass ays measuring both Epstein-Barr virus-derived and human IL-10 yielded highe r values than assays measuring primarily human IL<10 (P < .05), Patients wi th elevation of serum IL-6 or IL-10 levels, or both, had worse median and 3 -year survival (log rank P < .001) and unfavorable characteristics (prior t reatment, elevated <beta>(2)-microglobulin or lactate dehydrogenase, or Rai stage III or IV). Elevated IL-6 and IL-10 levels were independent prognost ic factors for survival when analyzed individually or in combination (Cox r egression analysis). However, if beta (2)-microglobulin was incorporated in to the analysis, it was selected as an independent prognostic feature, and IL-6/IL-10 were no longer selected. In patients with CLL, serum IL-6 and IL -10 (viral and human) levels are elevated and correlate with adverse diseas e features and short survival. In multivariate analysis, however, beta (2)- microglobulin is the most important prognostic factor. (C) 2001 by The Amer ican Society of Hematology.