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

Abstract

This study was designed to investigate the immunostimulatory effect of low dose 11–2 treatment in B-CLL patients previously treated with 2-chlorodeoxyadenosine (2CdA) in whom severe depletion of T lymphocyte subsets was observed. Four patients enrolled into the study had previously been treated with 3–6 courses of 2 CdA. All patients suffered from recurrent infections and showed CD4⁺ and CD8⁺ immunosuppression. Recombinant 11–2 was given subcutaneously at a dose of 100 μg (1.8 × 10⁶1U) daily for 6 weeks. The drug was administered between 2CdA courses. These preliminary studies showed a marked increase in T cell subsets after Il-2 treatment. All patients displayed an increase of NK cells and there was increased expression of Il-2 receptors (CD 25 and CD 122) on lymphocytes.

It is possible that the combination of cytotoxic therapy with 2CdA and low dose rII-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.

Key Words:

• 2CdA therapy
• CD 4⁺ depletion
• rII-2 therapy
• B-CLL
• B-chronic lymphocytic leukemia
• purine analogs
• 2-CdA. chlorodeoxyadenosine