Fibrogenic cytokines in vulvar lichen sclerosus: An immunohistochemical study

OBJECTIVE: To evaluate the expression of fibrogenic cytokines in lichen sclerosus (LS) infiltrate as compared with lichen planus (LP) infiltrate. STUDY DESIGN: Eight cases of vulvar LS (early stage, n = 3; well developed or old, n = 5) and 4 of vulvar LP were studied. Monoclonal antibodies directed against some of the major fibrogenic cytokines (IL-4, TGF-β, IL-6) and against IFN-γ, which inhibits collagen synthesis, were used per the alkaline phosphatase/anti-alkaline phosphatase technique on frozen sections. RESULTS: Staining for IL-4 revealed higher expression of fibrogenic cytokines (more than 50% infiltrating cells)in the LS infiltrate, mainly in early lesions, than in LP. Conversely, staining for IFN-γ in LS was poor (less than 10% infiltrating cells), while strong positivity (more than 60% infiltrating cells) was found in LP. Staining for TGF-β, a mediator of fibrosis in scleroderma, was similar in both LS and LP dermis. CONCLUSION: This study showed the immunohistochemical expression of fibrogenic cytokines in vulvar LS, with a different pattern as compared to that of LP. It is conceivable that dermal infiltrating cells actively participate, via cytokine production, in the pathogenesis of fibrosis in LS.