Immune mechanisms in atopic dermatitis: studies and hypothesis.

Abstract

SummaryThe pathogenesis of atopic dermatitis remains uncertain. The aim of this study was to correlate blood and skin findings with respect to analysis of immunoregulatory T cells in 18 patients with severe atopic dermatitis.Circulating T lymphocytes were characterised by flow cytometry, and in situ infiltrates of acute skin lesions identified by the immunoperoxidase technique. Analysis of peripheral blood T lymphocyte sub‐sets failed to reveal any difference from normal controls. Skin infiltrates were strongly positive for T11 – the pan T lymphocyte marker. The majority of these cells both in the dermis and epidermis were of the T4 helper‐inducer sub‐set, while a smaller proportion of cells were of the T8 suppressor‐ cytotoxic T cell sub‐set. T6 positive Langerhans cells were markedly increased in the dermis of affected skin, compared with normal skin.The finding of increased numbers of helper‐inducer T lymphocytes' in association with increased numbers of Langerhans cells, which function as antigen presenting cells, suggests a strong immunological mechanism in disease pathogenesis, and may yield knowledge both with respect to origin of skin damage and elevation of IgE.