Investigation of the level of cd4 + cd25 + foxp3 + pd-1 + regulator t cells and pd-1, pd-l1 mrna expression in bone marrow in new diagnosis multiple myeloma

Multiple myeloma (MM) is a cancer that plasma cells. In almost all patients may be develop relaps although new treatment options and stem cell transplantation. Increased regulatory T cell (Treg) has been associated with poor clinical outcome in which both newly diagnosed and treated MM patients. Treg cells are a T cell subgroup that suppressing immune response. Programmed cell death protein 1 (PD-1) signalling pathway play essential role in Treg function and development. PD-1 is accepted as an immune check point which protects against autoimmune responses by both inducing apoptosis in antigen-specific T cells and inhibiting apoptosis in Treg cells. In literature knowledge is insufficient about Treg cell distribution in the bone marrow microenvironment despite the presence of these clinical studies in MM. In this study, we aimed to investigate PD1+ Treg cell distribution and PD1/PD-L1 gene expression levels in MM patients bone marrow. In the study, twenty patients newly diagnosed MM cases and as control group nine patients with Idiopathic thrombocytopenic purpura (İTP) were included. Mononuclear cells were isolated from bone marrow by using density gradient centrifugation method. CD4, CD25, Foxp3 and PD1(CD279) protein expressions were evaluated flow cytometry on mononuclear cells. In order to determine mRNA expression of PD1 (PDCD1) and PD-L1 (CD274) genes, total RNA was obtained from bone marrow samples by silica column method. cDNA has been synthesized from mRNA through reverse transcriptase PCR. The relative expression levels of target genes were determined using the quantitative PCR method. The study, PD-1 and PD-L1 mRNA expressions were higher in MM patients. CD4+CD25+FoxP3+PD-1+Treg cells (%) measurements were found to be higher in MM patients. CD4+CD25+FoxP3+PD-1+ Treg cell (%) and PD-1 mRNA levels were not being show difference according to stage of patients. PD-L1 mRNA expressions were different according to the stage of the patients and the difference was due to the higher levels of PD-L1 mRNA expression of the stage I patients compared to Stage II and III patients. This study is important not only because it guides therapeutic options in patient treatment, but also in finding strategies to enhance response in patients treated with these drugs. KEYWORDS : Multiple myeloma, PD-1, PD-L1, Treg