The Frequency and clinical Implications of Lymphocyte Subsets and Circulating Plasma Cells in Newly Diagnosed Multiple Myeloma Patients

Abstract

Multiple myeloma (MM) is characterized by clonal proliferation of plasma cells (PCs) in the bone marrow (BM) leading to end organ damage. Recent interests are increasingly focusing on the quantitative and functional profiles of T-cell subsets, natural killer cells (NK) and natural killer T-cells (NK T), due to their importance in the development of MM. Herein we tried to evaluate the frequency of different lymphocyte subsets and cPCs in newly diagnosed MM patients and their impact on survival. This prospective case-control study included 40 newly diagnosed MM patients presented to South Egypt Cancer Institute (SECI), Assiut University and 20 apparently healthy controls. Flow cytometry was used for evaluation of CD4+ T helper cells, CD8+ T cytotoxic cells, natural NK cells, NK T cells and cPCs. CD4+ T helper cells were significantly decreased in MM patients while, cytotoxic CD8+ T cells were significantly increased in comparison to the controls leading to a significant decrease in the CD4+/CD8+ ratio in MM patients. In addition, MM patients had deficiency in NK cells and NK-T cells. The median number of cPCs was 8 (range: 0 - 477) per 50,000 cells in the MM patients. The median OS for those with < 8 cPCs was 22.5 months compared with 18 months for patients with ≥8 cPCs. In conclusion, alterations in the immune cells homeostasis in MM patients could play a role in the development of MM and may be associated with the release of plasma cells in the peripheral blood. Also, the quantitative estimation of cPCs in patients with newly diagnosed MM may be used as a predictor of survival.