Short Communication: Expression of Apoptosis Regulating Factors on T Lymphocytes in Multiple Myeloma Patients

Multiple myeloma (MM) is a malignant proliferation of plasma cells in which dysregulation of programmed cell death (apoptosis) is responsible for tumor cell expansion. However some phenotypic and functional alterations of T cells in MM patients have been reported, that also can influence the plasma cell growth. The aim of the study was to assess some aspects of T lymphocyte apoptosis in MM to obtain a better understanding of the changes in the immune system in this disease. Flow cytometry was used to analyze the expression of two main regulators of apoptosis: the pro-apoptotic Fas antigen and the anti-apoptotic protein BCL-2 in patients with untreated MM and in healthy controls. ELISA was used to determine soluble Fas ligand (sFasL) serum levels in patients and control groups. We detected statistically significant higher Fas expression in patients than in controls both on CD4 and CD8 lymphocytes, but no differences in BCL-2 expression by these cells. The sFasL level was statistically significant lower in patients than in controls. Our results indicate that T cells in MM are controlled by up-regulation of Fas. The Fas/FasL system induces the killing of T cells expressing Fas antigen, what could account for the incapability of the immune system to protect host against tumor expansion.