INSITU IMMUNOPHENOTYPING OF ANTIGEN PRESENTING CELLS AND T-CELL SUBSETS IN ATOPIC-DERMATITIS

Twelve patients with classical adult-type atopic dermatitis were biopsied from clinically active lesions. An extended panel of monoclonal antibodies which define immunocompetent cell subsets was used to immunophenotype the epidermal and dermal inflammatory cells present in situ. The dermis showed an impressively high T4/T8 ratio. Epidermal Langerhans cells were irregularly distributed and showed morphological alterations. Langerhans cells were only sporadically observed in layers deeper than the papillary dermis. A surprisingly high number of cells with the immunophenotype (RFD1+, HLA-DR+) of interdigitating cells was seen both in the epidermis and in the dermis. Monocytes, B cells, plasma cells and natural killer cells were only sporadically found. Active subacute adult atopic dermatitis was thus found to be mainly characterized by a remarkable high, in situ, T4/T8 ratio and a dermal preponderance of antigen presenting cells with the phenotype of interdigitating cells and to a lesser extent, Langerhans cells.