Erythema chronicum migrans: evidence for cellular immune reaction in the skin lesion

Skin biopsy specimens from 9 patients with erythema chronicum migrans (ECM) were studied immunohistochemically using a series of monoclonal antibodies. In biopsy specimens taken from the erythematous peripheral portion of ECM the perivascular infiltrates were composed predominantly of LEU-4+ T cells. LEU-3a + helper/inducer T cells were more numerous than LEU-2a + cytotoxic/suppressor T cells. Of particular interest was the high number of LEU-6+ Langerhans cells in the epidermis and dermis of specimens taken from the erythematous portion of ECM as well as from the noninflammatory skin outside the erythema. The presence of LEU-6+ Langerhans cells and T cells in the ECM lesions suggests that, apart from humoral factors, a cell-mediated immune response directed against Borrelia burgdorferi antigen is important as well in the pathogenesis of this disease.