Ia+ dendritic cells lining the dermo-epidermal junction in bullous skin disorders, associated with the deposition of immune complexes.

Skin biopsies from 34 patients, presenting with a variety of bullous skin disorders were investigated, using routine light microscopy and immunohistochemistry. In bullous skin diseases characterized by deposition of complement factors (CF) and/or immunoglobulins (Ig), a monolayer of OKIa+1, OKT-6, OKM-1 dendritic cells was found at the dermo-epidermal junction. Retrospectively, these cells were easily recognized on paraffin embedded, H & E stained material. In bullous skin disorders, showing no deposition of CF and/or Ig, this monolayer of dendritic cells was lacking. It is suggested that these OKIa+1, OKT-6, OKM-1 dendritic cells at the dermo-epidermal junction represent some type of antigen presenting cells, not corresponding to Langerhans cells, veiled cells or indeterminate cells.