Persistence of T-cell clones in psoriatic lesions

Background: We previously demonstrated a clonal dominance in the V beta 13.1 messages isolated from the lesional CD8(+) T cells of psoriasis vulgaris, which suggested an interaction of V beta 13.1(+) CD8(+) T cells with skin antigens. Objectives: To determine whether the clonality observed accurately reflected a clonal population of infiltrating T cells or was skewed by an overabundance of messages from a small number of cells, and to extend our study of V beta gene usage by lesional CD8(+) T cells to 9 new patients. Design: Case study. Setting: Patients were enrolled at the Psoriasis Research Institute in Pale Alto, Calif, and samples were analyzed at The Immune Response Corporation in Carlsbad, Calif. Main Outcome Measures: For the 2 previous patients, skin samples were sorted directly for V beta 13.1(+) T cells, for which the T-cell receptors were sequenced. For the 9 new patients, CD8(+) T cells were sorted and their T-cell receptor V beta gene usage measured using semiquantitative polymerase chain reaction with V beta-specific primers. Results: The directly sorted V beta 13.1(+) T cells exhibited clonal dominance in both patients. The dominant V beta 13.1 clone in each patient was the same as that found in the previous 2 biopsy specimens for which CD8(+) T cells were sorted. Additionally, in 8 of the 9 new patients examined, we again found a preferential usage of V beta 3 and/or V beta 13.1 genes by the lesional CD8(+) T cells. Conclusions: The clonality, which was found in the V beta messages of the sorted CD8(+) T cells, accurately reflects the dominance of these clones in the infiltrating T cells. Moreover, the persistence in the same patient of the same clone for as long as 15 months and the overrepresentation of V beta 3 and/or V beta 13.1 in lesional CD8(+) T cells in the new patients examined support the pathogenic role of T cells bearing these V beta s.