Therapy-Associated Immunosuppression and Opportunistic Infections in Multiple Myeloma Patients.

This study evaluates cellular and humoral immune parameters in myeloma patients focusing on the effect of treatment and the risk of opportunistic infections. Peripheral blood lymphocyte subsets and serum levels of nonmyeloma immunoglobulins (Ig) were analyzed in 480 blood samples from 77 myeloma patients. Untreated myeloma patients exhibited significantly reduced CD4+/45RO+, CD19+, CD3+/HLA-DR+, and natural killer (NK) cells as well as nonmyeloma IgA, IgG, and IgM. Conventional-dose chemotherapy (conv-CTX) resulted in significantly reduced CD4+ and even further decline of CD4+/CD45RO+ and CD19+ cells, most notably in relapsed patients. Patients treated with conv-CTX in combination with thalidomide showed significantly increased counts of monocytes as well as serum levels of nonmyeloma IgA and IgM as compared to patients on conv-CTX without additional thalidomide. Following high-dose chemotherapy (HD-CTX) prolonged immunosuppression was observed. While CD8+, NK, CD19+, and CD4+/CD45RO+ cells recovered to normal values within 60, 90, 360, and 720 days, respectively, CD4+ counts remaining reduced even thereafter. Nine opportunistic infections were observed including 5 cytomegalovirus (CMV) diseases, 1 pneumocystis carinii pneumonia (PCP), and 3 varicella zoster virus (VZV) infections with CMV diseases and PCP occurring exclusively after HD-CTX. Opportunistic infections were correlated with severely reduced CD4+ as well as CD4+/CD45RO+, and CD19+ counts. Thus, myeloma patients display cellular and humoral immunodeficiencies, which increase following conv- as well as HD-CTX and constitute an important predisposing factor for opportunistic infections.