Phenotypic analysis of CD23⁺ peripheral blood mononuclear cells in atopic dermatitis

Summary There is an increase in the number of CD23⁺ cells in peripheral blood mononuclear cells (PBMC) in atopic dermatitis (AD). We analysed the subpopulation of CD23⁺ PBMC in 11 patients with AD and in 10 healthy controls and found that B Cells (CD20⁺) and non‐T, non‐B cells (CD3^– CD20^–) (mainly monocytes) were responsible for the elevation of CD23⁺ CD23⁺ T Cells (CD3^–) comprised only 4.6% of total CD23⁺ cells in AD. The percentage of CD23⁺ cells did not correlate with the serum log IgE level nor with clinical severity of AD. Interleukin 4 (IL‐4) induced the expression of CD23 antigen in PBMC both in AD and in healthy controls in a dose‐dependent manner in vitro. This enhancing effect of IL‐4 was completely abrogated by the addition of anti‐IL‐4 monoclonal antibody. Other cytokines such as IL‐1, IL‐2, IL‐3, IFN‐α, IFN‐γ and TNF‐α had no significant effects on CD23 expression.