Quantitative studies on nonlymphoid mononuclear cell subpopulations in cutaneous infiltrates. I. Stage-related changes of dendritic nonlymphoid mononuclear cells, Langerhans' cells, and macrophages in lichen planus lesions.

Abstract

In previous investigations on lichen planus, we suggested that in early lesions T4-positive cells might be antigen-specifically driven, whereas in late lesions T8-positive cells may be cytotoxic to keratinocytes. To verify this hypothesis, we investigated the following nonlymphoid mononuclear cell subpopulations in early versus late lichen planus lesions: interdigitating cells (phenotype: S100-positive, lysozyme-negative, T6-negative, M3-negative), Langerhans cells (phenotype: S100-positive, lysozyme-negative, T6-positive, M3-negative), macrophages (phenotype: S100-negative, lysozyme-positive, T6-negative, M3-positive). Interdigitating cells were moreover identified in semithin and ultrathin sections by distinctive morphological characteristics. The S100-positive/lysozyme-positive cell ratio was higher (p less than 0.01) in early lesions than late lesions. In dermis but not in epidermis (NS), of early lesions, T6-positive cells were less represented than S100 positive cells (p less than 0.025). Thus, Langerhans' cells largely predominated over interdigitating cells in epidermis, but the two populations were both represented in dermis. Lysozyme-positive and M3-positive cells, more abundant in late lesions than in early lesions (p less than 0.001), were often filled with pigment granules.