Characterization of T lymphocyte subsets in hairy cell leukaemia: influence of splenectomy and correlations with the clinical stage of the disease.

Peripheral blood mononuclear cell surface markers were studied in a series of 26 hairy cell leukaemia patients 19 of whom were splenectomized previously. Patients with non-symptomatic and stable disease were distinguished from those with symptomatic and/or progressive disease (also termed "active" clinical stages). In all HCL patients as a group, the absolute number of CD4+ MN cells did not differ statistically from that of the controls, while the number of CD8+ MN cells was significantly increased. The reduction of the CD4/CD8 ratio in the peripheral blood of HCL patients as compared to the controls was explained by the reduction of this ratio in patients with "active disease", while the CD4/CD8 ratio of patients with non-symptomatic and stable disease did not differ statistically from that of the controls. The CD4/CD8 ratio was found to be influenced mainly by the clinical stage of the disease, and not by the effect of splenectomy.