Elevations in serum soluble interleukin-2 receptor levels predict relapse in patients with hairy cell leukemia

PURPOSE: Interferon-alfa, 2'-deoxycoformycin, and 2-chlorodeoxyadenosine (2-CdA) are effective in the management of patients with hairy cell leukemia. These agents produce remissions in most patients, but relapses occur with all three drugs. The optimal means to follow patients for relapse after treatment has not been determined. METHODS: We retrospectively examined serial serum soluble interleukin-2 receptor levels (sIL-2R) and absolute granulocyte counts in eight patients with relapsed hairy cell leukemia. All were treated with 2-CdA at the time of relapse. Serum samples were available at 3- to 6- month intervals from 5 to 9 years before relapse and 2-CdA treatment. RESULTS: sIL-2R levels increase only in patients who go on to relapse, sIL-2R levels doubled a mean of 17.1 months (range, 4-36 months) before absolute granulocyte count decreased by 50%. DISCUSSION: Demonstration of a rising serum sIL-2R level in patients with hairy cell leukemia identified those with an increased risk of relapse who need more frequent observation than patients who maintain a stable sIL-2R level. Early intervention may ameliorate the toxicity of salvage therapy because disease-related neutropenia may be anticipated.