Interleukin-3, interleukin-8, FMLP and C5a enhance the release of leukotrienes from neutrophils of patients with atopic dermatitis.

The influence of the receptor-specific stimuli interleukin-3 (IL-3), interleukin-8 (IL-8), C5a and formyl-methionyl-leucyl-phenylalanine (FMLP) on the generation of arachidonic acid-derived inflammatory mediators from neutrophils (PMN) has been studied in patients with atopic dermatitis (AD) as well as in healthy, non-atopic volunteers. The release of leukotriene (LT)B4, the omega-oxidation products 20-COOH- and 20-OH-LTB4 and the cysteinyleukotriene LTC4 were measured by reverse-phase HPLC and radioimmunoassay. The incubation of neutrophils with these stimuli led to a significantly higher release of LTB4 and LTC4 in the AD group. The spontaneous leukotriene generation of PMN from patients with AD was on average threefold higher compared to the control group. C5a stimulated the release of LTB4 and its metabolites from atopic cells up to 9 ng in contrast to low amounts from non-atopic cells. Furthermore, FMLP distinctly enhanced the leukotriene release of neutrophils from patients with AD compared to unstimulated cells and to cells of normal donors. IL-3 and IL-8 also significantly stimulated the generation of LTB4 and LTC4 of PMN from atopic patients. Our data emphasize that neutrophils may play an important role in the pathogenesis of AD by an increased responsiveness to receptor-specific stimuli and further suggest that IL-3 and IL-8 influence the acute and chronic inflammatory reactions in patients with AD.