Upregulation of CD40 and CD40 ligand expression in IgE-associated cutaneous diseases

In order to better understand the immunological processes connected with IgE-associated cutaneous disease, we have examined the expression of CD40 and its ligand CD40L, required for the induction of IgE synthesis in B-cells, as well as of IgE and its receptors in various dermatoses (atopic dermatitis (AD), scabies, chronic recurrent urticaria) versus normal skin, and in one dermopathic lymph node versus normal lymphatic tissue by immunohistochemistry. Compared to normal skin, cells expressing IgE, Pc epsilon RI, Fc epsilon RII, CD40, CD40L and L26 were increased in the dermis, partly also in the epidermis, from patients with AD and scabies, but not in chronic urticaria. CD40 and CD40L were detected on numerous cells in lymphatic tissue from both normal donors and a patient with AD, whereas large numbers of IgE- and Fc epsilon RI-positive cells were only found in the dermopathic lymph node from the AD patient, in contrast to very few in normal lymphatic tissue, These results with selectively increased IgE/Fc epsilon RI and associated CD40/CD40L expression in the skin of AD and scabies suggest that cutaneous tissue, in addition to dermopathic lymphatic tissue, might contribute to IgE synthesis.