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Detailed analysis of the T‐cell lymphocytic infiltrate in penile lichen sclerosus: an immunohistochemical and molecular investigation

2006; Wiley; Volume: 48; Issue: 6 Linguagem: Inglês

10.1111/j.1365-2559.2006.02406.x

1365-2559

Sigrid Regauer, Christine Beham‐Schmid,

Urological Disorders and Treatments

Aim : To determine the extent of clonal outgrowth in the lymphocytic tissue infiltrate of lichen sclerosus (LS). The presence of T cells with a monoclonally rearranged T‐cell receptor γ‐gene (TCRγ) has been described in up to 50% of biopsies of vulvar and penile LS. Material and results : We analysed 33 foreskin specimens with LS for the presence of clonal T cells by conventional polymerase chain reaction (PCR) analysis and with TCRγ‐PCR‐based fluorescent fragment analysis. Eighteen of 33 patients revealed a band indicating a monoclonally rearranged TCRγ on conventional PCR analysis. Subsequent TCRγ‐PCR‐based fluorescent fragment analysis identified 8/18 patients with monoclonal T‐cell DNA ranging from 1.4% to 23.1% of total T‐cell DNA analysed and a size range from 56 to 72 base pairs. Four of 18 patients had an oligoclonal and 6/18 patients revealed a polyclonal banding pattern. The lymphocytic infiltrate contained low numbers of γδ T cells and cytotoxic T cells in comparable numbers to the low percentage of clonal TCRγ DNA. Conclusions : The low percentage of clonal TCRγ DNA argues against a systemic neoplastic disease, but rather for a local immune disorder. The target antigen of the clonal outgrowth is unknown, but an exaggerated antigen‐dependent proliferation of T cells due to chronic local antigen exposure, probably an infectious antigen, is the most likely explanation.