Altered production of immuno-modulating cytokines in patients with atopic dermatitis

Atopic dermatitis (AD) represents an inflammatory skin disorder which is characterized by many signs of immunodeficiency. Particularly, decreased lymphoproliferative responses upon stimulation with mitogens as well as bacterial antigens were reported repeatedly. Since there is increasing evidence for a network of immuno-modulating cytokines playing a crucial role in the regulation of immunity and inflammation, in the present study we investigated whether an altered production of these mediators is one of the pathomechanisms responsible for the altered immune response in AD. For this purpose the 24-h supernatants of LPS- and PHA-stimulated or unstimulated mononuclear cells (MNC) from patients with AD of a moderate to severe disease activity and from nonatopic healthy controls were tested for Interleukin-1 (IL-1) and Interleukin-2 (IL-2) activity. Whereas supernatants of unstimulated MNC of AD patients and controls did not contain significantly different levels of these cytokines, LPS-stimulated MNC of AD patients released significantly less IL-1 in the supernatants. Similarly, the production of IL-2 by PHA-stimulated MNC of AD patients was significantly decreased in comparison to the controls. Moreover, there was a strong correlation between IL-1 and IL-2 levels. These findings indicate that diminished lymphoproliferative responses in AD may partly be caused by a decreased capacity of MNC to release immuno-modulating cytokines, even upon appropriate stimulation.