Naturally occurring regulatory T cells in mucous membrane pemphigoid lesions.

BACKGROUND A growing body of evidence suggests the involvement of naturally occurring CD4+ CD25+ regulatory (nTreg) T cells in autoimmune diseases. OBJECTIVE To evaluate the expression of some nTreg markers in mucous membrane pemphigoid (MMP) lesions. METHODS Lesional biopsies from six patients with untreated MMP were stained immunohistochemically with anti-CD25, -FoxP3, -CD103, and -CCR5. RESULTS All of the stained cells, both in MMP lesions and controls, were observed in the interstitial lamina propria or dermis. Positive cell counts of all the markers studied were low or very low in all sections, and significantly higher in MMP specimens than in healthy controls. CONCLUSIONS The expression of CCR5 and CD103, which mediate recruitment into peripheral tissues, indicates that CD25+ FoxP3+ nTreg cells may be present in MMP lesions according to a specific homing. nTreg cells may contribute to directing the MMP immunoinflammation towards chronicity, and thus favor the cicatricial evolution of lesions.