Biological markers and minimal residual disease in hairy cell leukemia

Soluble Interleukin-2 Receptor (sIl-2R) and Tumor Necrosis Factor-alpha (TNF-alpha) have been found significantly increased in serum samples of patients with HCL at diagnosis and a strict correlation with leukemic burden has been reported. Furthermore, following therapy, serological monitoring of these cytokines may be considered a useful tool for controlling therapeutic efficacy and for detection of minimal residual disease. Eighteen HCL patients, treated with 2-Chlorodeoxyadenosine (2-CdA) at a dose of 0.1 mg/kg daily for 7 days, entered the study all of them showing increased levels of sIL-2R and TNF-alpha prior to therapy. After therapy, serum levels were reassessed and a remarkable decrease was recorded in all cases. In particular, after 1 month by the end of treatment sIL-2R and TNF-alpha decreased from 3,377 +/- 2,303 to 149 +/- 96 pM/ml (p = 0.00003) and from 38 +/- 41 to 18 +/- 18 pg/ml (p = 0.015) respectively. The only 3 patients who did not normalize sIL-2R and TNF-alpha levels showed also an evident persistence of the disease in the marrow. In conclusion, 2-CdA leads to a rapid normalization of the increased levels of sIL-2R and TNF-alpha in the majority of HCL patients. Furthermore, monitoring of these cytokines represents a useful tool for detecting minimal residual disease.