The role of increased frequency of treg cells in patients with chronic osteomyelitis.

摘要

The aim of this study is to determine whether regulatory T cells (Treg cells) are increased in patients with chronic osteomyelitis and whether they suppress cellular immune responses to the bacteria. The frequency of circulating CD4(+)CD25(+) and CD4(+)CD25(+)FoxP3(+) T cells in 30 chronic osteomyelitis patients were compared with 30 healthy donors. Treg-depleted PBMCs from the patients were cultured together with autologous antigen, unfractioned PBMCs used as the control. The cell proliferation and production of IL-10 and IFN-gamma were compared with those of the control. The results demonstrated that frequencies of CD4(+)CD25(+) (10.85+/-2.82% vs 6.08+/-1.62%, P<.001) and CD4(+)CD25(+)FoxP3(+) T cells (2.06+/-0.83% vs 1.43%+/-0.51%, P<.001) in blood from chronic osteomyelitis patients were significantly higher than in healthy donors. The level of IL-10 (117+/-91 pg/ml vs 323+/-189 pg/ml, P<.001) in supernatants of Treg-depleted PBMCs was decreased. Cell proliferation (4489+/-11876 cpm vs 3547+/-1517 cpm, P<.05) and IFN-gamma (875+/-203 pg/ml vs 405+/-129 pg/ml, P<.001) production by CD4(+)CD25(+) T cell in response to antigen was significantly inhibited by CD4(+)CD25(+) T cells. These results indicate that specific Tregs can depress the T cell mediated immune responses to bacteria in chronic osteomyelitis, and may play an important role in the persistence of bacteria.