Restricted T-cell receptor Vβ gene usage in the skin of patients with guttate and chronic plaque psoriasis

A strong association between acute guttate psoriasis and group A, β-haemolytic streptococcal infections is well established. Furthermore, streptococcal M proteins and toxins have been shown to act as superantigens, stimulating subpopulations of T lymphocytes expressing particular Vβ families. We have therefore studied the possible role of streptococcal superantigens in psoriasis by staining peripheral T lymphocytes and skin sections from patients with guttate or chronic plaque psoriasis for the expression of nine TCR Vβ families, using a range of monoclonal antibodies. A marked over-representation of Vβ2⁺ T lymphocytes was observed in the dermis and epidermis of patients in both groups, when compared with T lymphocytes in their peripheral blood. A less marked dermal increase in Vβ5.1⁺ T lymphocytes was also observed in these patients. These findings are consistent with the involvement of a superantigen, possibly streptococcal, in the pathogenesis of psoriasis.