Gamma-interferon promotes the release of IgE-binding factors (soluble CD23) by human epidermal Langerhans cells.

In a previous study, we have demonstrated that human epidermal Langerhans cells (LC) are induced to express Fc epsilon R2/CD23 by stimulation with IL-4 and/or IFN-gamma. In this study, using LC-enriched and LC-depleted epidermal cell (EC) cultures, we have shown that stimulation with IL-4 and/or IFN-gamma not only led to Fc epsilon R2/CD23 expression on normal human LC but also to the release of significant amounts of IgE-BF (soluble CD23). Furthermore, stimulation with IL-4 was more effective in induction of Fc epsilon R2/CD23 on LC when compared to IFN-gamma, which, in contrast, strongly promoted the release of IgE-BF. These results indicate that Fc epsilon R2/CD23-positive LC represent a potential source of IgE-BF and that, as is observed in monocytes or U937 cells, IFN-gamma and IL-4 differently regulate the Fc epsilon R2/CD23 expression and release on LC.