OBJECTIVETo investigate the ratio of Th17 cells and CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells in peripheral blood from patients with multiple myeloma (MM) and explore its pathological effects.

METHODS70 MM patients were divided into three groups: newly diagnosed group (n=30), plateau stage group (n=23) and relapsed/refractory group (n=17). The controls consisted of 20 healthy donors. The frequencies of Th17 and Treg cells were detected by flow cytometry.

RESULTSCompared with controls [(0.72±0.33)%] and plateau stage group [(0.74±0.29)%], frequencies of Th17 cells were higher in newly diagnosed group [(1.62±0.65)%] and relapsed/refractory group [(1.45±0.51)%], respectively (P<0.05). Compared with controls [(2.33±0.90)%] and plateau stage group [(1.69±0.70)%], frequencies of Treg cells were significantly lower in newly diagnosed group [(0.55±0.23)%] and relapsed/refractory group [(0.82±0.54)%], respectively (P<0.05). The ratios of Th17/Treg in newly diagnosed group and relapsed/refractory group were higher than those in controls (P<0.05). There were no differences of the frequencies of CD3⁺CD4⁺ T cells and Th17 cells between plateau stage group and controls. The frequencies of Treg cells were significantly lower in plateau stage group than that in controls (P<0.05), and the ratio of Th17/Treg was significantly higher in plateau stage group than that in controls (P<0.05).

CONCLUSIONThe remarkable abnormality of T cells subsets was reduction of CD4⁺ T cells in MM. Higher frequency of Th17 and lower ratio of Treg could lead to imbalance of Th17/Treg, which may play a critical role in the pathogenesis of MM.