Langerhans cell accumulation in chronic tinea pedis and pityriasis versicolor.

Persistence of chronic tinea pedis (CTP) and pityriasis (tinea) versicolor (PIVE) has been tentatively attributed to an impaired cellular immune response. Therefore immunophenotyping of the inflammatory infiltrates in both disorders was performed in order to detect possible defects in cellular defence. The results of the present study show a dominance of memory T cells, an accumulation of macrophages and lack of B cells. A very prominent feature in CTP and especially PIVE was a marked accumulation of Langerhans cells (LCs) in the epidermis, mostly without expression of CD4. Furthermore, reduced expression of cellular activation markers and the presence of suppressor T cells was noted. In general, the cellular response in PIVE appeared to be slightly stronger than in CTP. This composition of the inflammatory infiltrates in chronic dermatomycoses is similar to previous findings in a variety of dermatoses. However, in PIVE and CTP local reduction of delayed-type hypersensitivity may occur. The function of LCs in these infections is therefore of special interest.