RESPONSE DURATION AND RECOVERY OF CD4(-ALPHA-RESISTANT HAIRY-CELL LEUKEMIA - 7-YEAR FOLLOW-UP() LYMPHOCYTES FOLLOWING DEOXYCOFORMYCIN IN INTERFERON)

The long-term outcome of patients with hairy cell leukemia resistant t o interferon-alpha (IFN-alpha) following treatment with deoxycoformyci n (DCF) was examined, and the kinetics of recovery of lymphocyte subse ts and factors influencing the rate of recovery investigated. Between May 1986 and May 1989, 15 patients with histologically confirmed hairy cell leukemia resistant to IFN-alpha received DCF 4 mg/m(2) every 2 w eeks with 12 cycles planned. All 15 patients were evaluable for respon se and have been followed for a median of 88 months (range, 72 to 106 months) from the start of therapy. Fourteen patients responded to DCF, all attaining complete remission (CR) (response rate 93%; 95% confide nce interval, 69% to 100%). Seven patients have developed recurrent di sease after 45 to 74 months. Using the method of Kaplan and Meier, the median remission duration is 74 months and, at 8 years, 46% (95% conf idence interval, 33% to 59%) of patients are projected to be in ongoin g CR. The seven relapsing patients have responded to treatment with 2- chlorodeoxyadenosine (2-CdA) and all 15 patients remain alive. After D CF, nadir CD4(+) and CD8(+) lymphocyte counts were significantly lower than prior to therapy (P<0.0001 and P=0.05, respectively), but return ed to baseline levels during follow-up. Median times to attainment of the lower limit of the normal range of CD4(+) and CD8(+) lymphocytes w ere 54 and 36 months, respectively. Those patients who had previously undergone splenectomy (n=7) had higher baseline CD4(+) (P=0.073) and C D8(+) (P=0.043) lymphocyte counts and more rapid recovery of both CD4( +) (P=0.027) and CD8(+) lymphocyte counts (P=0.016) than non-splenecto mized patients. One elderly patient (age, 78 years) was diagnosed with subsequent malignancy. No late opportunistic infections were observed . Resistance to IFN-alpha does not impair subsequent responsiveness of patients with hairy cell leukemia to treatment with DCF. Responses ar e durable and without evidence of long-term sequelae. CD4(+) and CD8() lymphocyte subsets recover slowly without clinical manifestations of immunodeficiency. Splenectomized patients appear to have higher basel ine lymphocyte counts and more rapid lymphocyte recovery following tre atment with DCF.