Circulating level of regulatory T cells in rheumatic heart disease: An observational study

The regulatory T cell (Treg) is essential for prevention of autoimmunity. In a preliminary study, we showed significant deficiency of Tregs (CD4CD25 T cells) in rheumatic heart disease (RHD) patients (an autoimmune disease), but the markers used could not reliably differentiate Treg from nonregulatory conventional T cells (Tcon). The study aim was to reassess the level of circulatory Tregs by using more specific markers.

70 adults of RHD and 35 controls were studied. Patients were subdivided according to the extent of left-sided valvular involvement. 35 patients with significant mitral-valve disease only were enrolled in the univalvular group while 35 patents with significant involvement of both mitral and aortic-valves in the multivalvular group. Circulating Treg cell level was determined by flow-cytometry.

Level of Tregs (CD4+CD25(med-high)CD127(low) Foxp3(high)) in CD4+ T lymphocyte was significantly lower in RHD patients compared to controls (median 0.6% versus 3.2%; p=0.001) with no significant difference in Tcon cells (p=0.94). Within the study group Treg count was significantly lower in patients with multivalvular-disease only (median 0.1% versus 3.2%; p=0.001) with no significant difference in Treg cell count between the univalvular group and control (median 1.9% versus 3.2%, p=0.10).

There is significant deficiency of circulating Tregs in patients of chronic RHD and the deficiency is greater in patients with multivalvular than univalvular involvement.