Attempted reconstruction of the immune system using low doses of interleukin 2 in chronic lymphocytic leukemia patients treated with 2-chlorodeoxyadenosine: Results of a pilot study

This study was designed to investigate the immunostimulatory effect of low dose IL-2 treatment in B-CLL patients previously treated with 2-chlorodeoxy adenosine (2CdA) in whom severe depletion of T lymphocyte subsets was obser ved. Four patients enrolled into the study had previously been treated with 3 - 6 courses of 2 CdA. All patients suffered from recurrent infections an d showed CD4(+) and CD8(+) immunosuppression. Recombinant Il-2 was given su bcutaneously at a dose of 100 mu g (1.8 x 10(6)IU) daily for 6 weeks. The d rug was administered between 2CdA courses. These preliminary studies showed a marked increase in T cell subsets after Il-2 treatment. All patients dis played an increase of NK cells and there was increased expression of Il-2 r eceptors (CD 25 and CD 122) on lymphocytes. It is possible that the combination of cytotoxic therapy with 2CdA and low dose rIl-2 could stimulate the T-cell immune system and may be a promising regimen in patients with B-CLL with severe depletion in T-cell subsets.