Significance of Foxp3+CD4+ regulatory T cells in the peripheral blood of Uygur patients in the acute and chronic phases of pigeon breeder's lung.

Pigeon breeder's lung (PBL) is a type of lung inflammatory disease associated with the immune response to repeated pigeon-derived antigen exposure. The pathogenesis of PBL remains unclear. In this study, peripheral blood samples were collected from Uygur acute - and chronic-phase PBL patients and healthy subjects with pigeon contact. Foxp3+CD4+ regulatory T cell (Treg) activity in different phases of PBL was characterized by changes in Foxp3+CD4+ Treg, CD4+CD25+ T cell, and T lymphocyte subsets. Based on hypersensitivity pneumonitis (HP) diagnosis criteria, 32 PBL cases from January 2012 to December 2013 in the People's Hospital of Xinjiang Uygur Autonomous Region Respiratory Department were included. Lung high-resolution computed tomography was performed, and the cases were classified based on the HP phase into 15 acute-phase and 17 chronic-phase cases. The control group included 30 healthy subjects with Uygur pigeon contact. Blood samples were collected, and the T cell subsets were analyzed via flow cytometry. In both PBL groups, the Foxp3+CD4+ Treg and CD4+CD25+ and CD4+CD3+ T cell percentages and CD4+/CD8+ ratios were significantly lower than in the control group (p < 0.01). In the PBL groups, particularly the acute-phase group, the CD8+CD3+ T lymphocyte percentage was significantly higher than in the control group (p < 0.01). There were no significant differences in CD4+CD25+ cells between the PBL groups. In peripheral blood from the PBL groups, the CD4+/CD8+ ratio was positively correlated with the Foxp3+CD4+ Treg (r = 0.864, p < 0.05) and CD4+/CD25+ cell (r = 0.34, p < 0.05) percentages. Low Foxp3+CD4+ Treg expression or overconsumption may be a pathogenic factor in PBL.