Decrease in CD4+CD25+FoxP3+ Treg cells after pulmonary resection in the treatment of cavity multidrug-resistant tuberculosis.

OBJECTIVES: Immune regulatory mechanisms may limit the immunopathologic condition of infection with Mycobacterium tuberculosis and suppress cellular immune responses in the host. We investigated the CD4(+)CD25(+)FoxP3(+) circulating regulatory T cells (T(reg)) in patients with cavity multidrug-resistant tuberculosis (MDR-TB) before and after surgery. METHODS: We compared the proportion of T(reg) cells in 13 patients with cavity MDR-TB pre- and postoperatively and in 10 healthy control subjects by flow cytometry using three specific markers in peripheral blood lymphocytes: cell-surface CD4 and CD25 expression and intracellular FoxP3 expression. RESULTS: The proportion of CD4(+)CD25(high) and CD4(+)CD25(+)FoxP3(+) T(reg) was significantly higher in patients with cavity MDR-TB and at 1-month postoperatively than in healthy controls (p<0.001). The proportion of CD4(+) and CD4(+)CD25(-) cells was significantly lower in patients with cavity MDR-TB than in controls (p<0.001). Pre- and postoperative proportions of CD4(+)CD25(high) and CD4(+)CD25(+)FoxP3(+) T(reg) cells showed a positive correlation (r=0.878, p<0.001). CONCLUSION: Circulating T(reg) cells are increased in proportion in patients with cavity MDR-TB and decreased after surgery. Infection with M. tuberculosis may induce T(reg) cell-surface molecular changes with increased numbers of cells.