Latchman, Yvette Eglantina; (1996) Atopic eczema: A comparison of zemaphyte [trademark], a traditional Chinese herbal treatment and corticosteroids on CD23 expression, cytokine production and cell mediated function <italic>in vitro</italic>. Doctoral thesis (Ph.D), UCL (University College London).

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Abstract

Atopic eczema (AE) is a chronic relapsing inflammatory skin disorder with multiple cellular and humoral defects. CD23, the low affinity IgE receptor is upregulated in the skin and peripheral blood mononuclear cells in patients with AE. The high affinity IgE receptor, together with CD23 may be important in the chronic T cell infiltration seen in the skin of these patients. The aetiology of the disease is not known thus treatment has focused on the reduction of inflammation in the skin by corticosteroids and other treatments. Two double blind placebo controlled trials of a decoction of 10 Chinese herbs, Zemaphyt[trademark] (ZPT) have demonstrated the efficacy and safety of this treatment in AE. However, the mode of action of this treatment is still unknown and thus the effect of an aqueous extract of ZPT on interleukin 4 (IL-4) induced CD23 expression on the peripheral blood monocytes from non-atopic subjects and patients with AE was investigated. ZPT inhibited CD23 expression up to 60[percent] whereas an aqueous placebo extract (PL) had no significant effect on this expression. This inhibition was not due to cell death as there is no change in cell viability and superoxide production by monocytes in peripheral mononuclear cell cultures (PBMCs). In comparison to prednisolone, ZPT showed a similar inhibitory activity on CD23 expression however cyclosporin, another treatment used in AE, had no significant effect on this expression. ZPT is a complex mixture consisting of many molecules, by mass spectroscopy two possible molecules were isolated which inhibited the expression of CD23. Along with its action on CD23, ZPT decreased the production of IL-4 and increased TNF - [alpha] and IL-10 production by concanavalin A stimulated PBMCs. Treatment of patients with ZPT resulted in the reduction of activation markers for T cells and soluble adhesion molecules in the serum with no change in total IgE. Down regulation of the low affinity receptors for IgE on antigen presenting cells, adhesion molecules and activation markers on T cells in patients with atopic eczema may contribute to the benefit observed following treatment with ZPT. The purified molecule which downregulated CD23 will have to be further elucidated to determine its therapeutic benefit in AE.

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