Lymphocyte recovery and clinical response in multiple myeloma patients receiving interferon α2β after intensive therapy

Abstract

The recovery of immunoregulatory cells in the peripheral blood of patients with multiple myeloma receiving maintenance therapy with interferon α2β (IFN-α2β) after intensive therapy with high-dose melphalan and autologous bone marrow or peripheral blood stem cell rescue was studied. IFN-α2β significantly inhibited the recovery of CD3+, CD4+, CD8+, CD56+/CD3- and CD16+/CD3- lymphocytes compared with numbers found in patients who had no further post-transplant treatment, but had no effect on the recovery of CD19+ cells. Among patients who did not receive IFN-α2β, the number of CD8+, CD56+/CD3- and CD16+/CD3- lymphocytes recovered to values similar to normal volunteers with increasing time after intensive therapy, however the number of CD4+ cells remained significantly below levels found in normal volunteers. Although CD16+/CD3- and CD56+/CD3- cell numbers were reduced in patients receiving IFN-α2β, natural killer (NK) activity was not effected. The levels of soluble interleukin 2 receptor (sIL-2R) were similar in all patients and IL-2 was not detected in any patient. At the time of writing, of the total of 69 patients, seven have relapsed, of whom three were receiving IFN-α2β, however there was no correlation between the absolute numbers of any lymphocyte subset with imminent relapse. The data suggest that the recovery of a specific lymphocyte subset(s) in peripheral blood is unlikely to be associated with the maintenance of response after intensive therapy.