Increased apoptosis of regulatory T cells in Crohn's disease

Crohn's disease (CD) is characterized by a transmural often granulomatous Th1-driven inflammatory process hallmarked by an increased production of IL-12, TNF-alpha and IFN-gamma. Accumulating evidence suggests that the numerical defect within the regulatory T cell (Tregs) compartment might contribute to this imbalance between pro- and antiinflammatory factors. This study was aimed to investigate whether the numerical defect of Tregs observed in CD resulted from an increased apoptosis of these cells.

The cytometric analysis was performed to evaluate the percentage of CD4 + FOXP3 + Tregs in peripheral blood of 55 investigated subjects, as well as to estimate the rate of Treg apoptosis.

The cytometric analysis showed a significantly lower percentage of Tregs in peripheral blood of CD patients compared with the healthy control group (P = 0.03) as well as an increased rate of apoptosis within this cell subpopulation (P = 0.000001). Interestingly, a significantly higher rate of Treg apoptosis was observed in female than male CD patients (P = 0.03).

Current data suggest that CD is associated with a numerical deficiency of the Treg compartment. Presented study indicates that an increased apoptosis might contribute to this numerical deficiency. A higher rate of Tregs apoptosis found in female patients might suggest the involvement of hormonal factors and possibly contribute to the female predominance observed in CD as well as to the tendency of female patients to develop a more severe form of the disease.