Study On The Change Of Tregs In Peripheral Blood And The Role Of Hepcidin And GDF15in Anemia Of Patients With Multiple Myeloma

ObjectiveTo investigate the changes and clinical significance of CD4+CD25+CD127low regulatory T cells (Tregs) in multiple myeloma (MM). And the role of hepcidin and GDF15in anemia of patients with MM. would be explored.MethodsPart I The levels of CD4+T cells and Tregs and the expressions of CTLA-4, apoptosis related proteins CD95, Bcl-2and Caspase3of Tregs in peripheral blood of30cases of newly diagnosed,27cases of completely remission (CR) MM patients and25healthy adults were analyzed by flow cytometry. Part II Selected25cases of MM patients and15cases of normal controls, then detected the expressions of HAMP mRNA and GDF15mRNA in mononuclear cells isolated from blood by lymphatic separated liquid by fluorescence quantitative PCR. Plasma hepcidin, GDF15, IL-6and EPO levels were measured by ELISA, and detected ferritin, plasma iron, total iron binding capacity and transferrin protein by conventional methods.ResultsPart I The percentage of CD4+T cells in the untreated group (29.41±12.56)%was significantly lower than this in controls (31.13±12.38)%(P<0.05),The percentage of Tregs in CD4+T cells in the untreated group (9.34±4.74)%was significantly higher than these in the CR group (7.31±2.10)%and controls (6.95±1.59)%(P＜0.05), which in ISS III patients(10.57±5.21)%of the untreated group was significantly higher than this in Ⅰ/Ⅱ(6.78±2.34)%(P＜0.05); There was no significant difference of expression of CD95in Tregs among the three groups (61.30±13.0%vs59.65±9.68%vs58.79±9.53%). The expression of CTLA-4of Tregs in untreated group (4.65±1.68)%was significantly higher than these in CR group (2.83±1.72)%(P<0.05) and controls (1.64±0.85)%(P＜0.01), and so was in CR group than this in controls (P<0.05). The expression of Bcl-2of Tregs in untreated group (772.02±196.34) was significantly higher than these in CR group (597.39±126.84)(P＜0.05) and controls (456.93±74.75)(P＜0.01), and so was in CR group than this in controls (P＜0.05). The expression of Caspase3of Tregs in untreated group (32,48±6.97) and CR group (37.69±7.59) were all significantly lower than this in controls (53.15±3.55)(P＜0.05). The percentage of Tregs in CD4+T cells in the untreated group was positively correlated with the proportion of bone marrow plasma cells (P＜0.05). The percentage of Tregs in CD4+T cells from15MM patients who received VD (bortezamib and dexamethasone) chemotherapy was negatively correlated to the ratio of plasma cell reduction after the first VD chemotherapy (r=0.735P＜0.01). Part II The relative expression of HAMP mRNA and GDF15mRNA in MM patients were (4.32±2.45) and (2.41±1.02)folds higher than those in the controls respectively (both P＜0.001), and plasma hepcidin, GDF15, IL-6and EPO in MM patients (63.73±17.46ng/ml,1241.65±688.37pg/ml,11.12±14.46pg/ml,64.44±61.71μIU/ml) were all more significantly increased than those in controls (33.25±16.05ng/ml,401.31±92.37pg/ml,2.92±1.97pg/ml,30.70±25.30μIU/ml)(both P＜0.05). The patients’HAMP mRNA expression was positively correlated with their serum ferritin but negatively correlated with their HB. Their GDF15mRNA expression was not correlated with ferritin and HAMP mRNA. The correlation between plasma EPO and GDF15was of borderline significance with a P value of0.06. Plasma hepcidin and GDF15showed significant decrease after6cycles VD (bortezomib and dexamethasone) regimen chemotherapy compared with the baseline levels (hepcidin65.60±21.83ng/ml vs44.33±14.50ng/ml、GDF151544.83±592.82pg/ml vs866.48±407.36pg/m)(both P＜0.05).Conclusions(1) The level of Tregs in PB of MM patients was positively correlated with tumor burden and progression of disease, but was negatively correlated with curative effect. The increased level of Tregs was associated with their strengthened anti-apoptosis function.(2) The overexpression of HAMP mRNA resulting in increased plasma hepcidin might play an important role of MM related ACD. GDF15might not primarily affect iron homeostasis and hepcidin expression in MM. Furthermore, the levels of serum hepcidin and GDF15might be valuable to assess the prognosis of MM.