Since December 1987, 115 patients with HCL have been enrolled in a prospective multicenter study to evaluate the role of splenectomy after an induction therapy with alpha interferon. The group of patients was divided into two categories: those younger and those older than 65 years. The schedule of treatment with IFN was, respectively, 1.8 MU/sm/daily and 1.0 MU/daily, 33 patients were treated with r-alpha-2a, 34 with r-alpha-2b, and 25 with alpha-Ly. To date, 92 patients are fully evaluable. The response was assessed every 3 months by bone marrow trephine biopsy. Patients in CR continued IFN therapy for 3 months and, if they were still in CR, could undergo an optional splenectomy. Patients in PR continued therapy for 12 months and subsequently were randomized for splenectomy or observation only. In these preliminary results of an ongoing protocol, CR was obtained in 5 cases (6%), PR in 59 (64%), MR in 25 (27%), NR in 3 (3%). Only 2 of the 5 patients in CR underwent splenectomy and are still in CR. Of the 59 patients in PR, only 15 completed 12 months of therapy. 9 patients in Group A were randomized, 4 were splenectomized and 5 were in the observation arm. All patients were splenectomized safely and no complications occurred. These preliminary results suggest that splenectomy could be effective in consolidating the response obtained with IFN.