Hematologic and immunologic changes in hairy cell leukemia patients treated with alpha interferon.

We prospectively evaluated hematologic and immunologic changes in fourteen hairy cell leukemia patients treated with alpha interferon. Prompt disappearance of circulating hairy cells, and recovery of peripheral blood counts was observed in all patients whereas only four patients had complete disappearance of hairy cell infiltrates from their bone marrow. Immunologic changes included a statistically significant increase of NK cell activity in the whole group and a slight decrease in circulating T cells with a strong trend towards an increase in the T4/T8 lymphocyte ratio (in eight of fourteen patients). Serial hemopoietic progenitor cell culture studies from peripheral blood (thirteen patients) and bone marrow (two patients) showed no correlation between hematologic recovery data and cell culture data.