Regulatory T Cells Are Severely Reduced in Pemphigus Vulgaris

Several T cell subsets with immunosuppressive functions have been reported to demonstrate their suppressive capabilities to the acquired immune system in animal autoimmune disease models. Among them, CD4+ T cells constitutively expressing CD25, termed CD4+CD25+ regulatory (Treg) cells, are considered to be the major controllers of autoreactive T cells, thus maintaining immunological self-tolerance. The human equivalent was identified in CD4+ T cells expressing only high levels of CD25 (CD4+CD25high regulatory T (Treg) cells).

This study examined the number and function of CD4+CD25high Treg cells in PV. Peripheral blood mononuclear cells were prepared from PV patients as well as normal and disease control volunteers, and the frequency and phenotypes of T cells were determined by flow cytometry. CD4+CD25+ and CD4+CD25- T cells isolated from peripheral blood mononuclear cells of PV patients and normal controls were subjected to real-time semiquantitative RT-PCR for the expression of Foxp3 gene.

The proportion of T cells in all PV patients was severely reduced, approximately ten times less than in controls. These observations were further confirmed by both diminished gene and protein expression of Foxp3 in the CD4+CD25+ T cell population in PV patients. However, additional studies are needed to further clarify the role of T cells in the pathogenesis of PV.