SERUM-SOLUBLE IL-2 RECEPTOR AS A RELIABLE AND NONINVASIVE MARKER OF DISEASE-ACTIVITY IN PATIENTS WITH HAIRY-CELL LEUKEMIA

Hairy cell leukemia is a chronic lymphoproliferative disorder of B-cel l lineage. Malignant cells express the interleukin-2 receptor (IL-2R) which is released in vitro as well as in vivo. The sera of patients wi th hairy cell leukemia contain elevated levels of this soluble recepto r (sIL-2R). Sera of 24 patients with hairy cell leukemia were tested f or sIL-2R. In 9 patients treated with 2-chlorodeoxyadenosine an improv ed clinical status was associated with decreasing serum sIL-2R. The ma ximal rate of decrease of sIL-2R level was observed within the second and the third week after the therapy initiation. Patients with disease progression had an increase in serum sIL-2R level. Our results sugges t that serial measurement of sIL-2R level can be used as a reliable, n oninvasive means to assess the disease activity and its response to th erapy.