title: The role of increased frequency of treg cells in patients with chronic osteomyelitis.
abstract: 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-γ 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-γ (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.
authors.affiliation: Research Center, The Second Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Wu
authors.forename: Yong
authors.initials: Y
authors.lastname: Tang
authors.forename: Xinjun
authors.initials: X
authors.lastname: Liang
authors.forename: Yongping
authors.initials: Y
authors.lastname: Lin
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Yuanchen
authors.initials: Y
authors.lastname: Ma
authors.forename: Lin
authors.initials: L
authors.lastname: Huang
authors.forename: Rui
authors.initials: R
authors.lastname: Yang
authors.forename: Jichao
authors.initials: J
authors.lastname: Ye
authors.forename: Keng
authors.initials: K
authors.lastname: Chen
authors.forename: Huiyong
authors.initials: H
authors.lastname: Shen
mesh_terms: D000328:Adult; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D010019:Osteomyelitis / Q000276:immunology* / Q000473:pathology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000473:pathology*