Ex vivo induction of cytokines by mould components in whole blood of atopic and non-atopic volunteers.

We investigated the time-course release of IL-1beta and IL-8 protein as well as the steady state mRNA level of their genes in human whole blood after stimulation with LPS, beta-1,3-D-glucan and mould extracts. We compared the response of 10 non-atopic and 10 atopic individuals. In parallel, cytokine protein release and the corresponding steady state mRNA level was determined by the standard ELISA and real-time on-line RT-PCR methods, respectively. Glucan induced the highest level of IL-1beta mRNA and protein release after 3 h. IL-8 was induced at 3 h after glucan, but not after LPS, induction, which indicates different induction pathways. At the time-points found to elicit the optimal cytokine response significantly higher basal cytokine mRNA levels and significantly lower LPS induced cytokine mRNA levels were observed in the non-atopic group. Generally, mould components induced cytokine mRNA steady state to lower levels in the atopics compared to the non-atopics. In contrast, no differences were found between the two groups in their capacity to induce cytokine protein release. These findings persisted after correction for the percentage of mononuclear cells. The data supported our hypothesis that "exhaustion" of the atopic immune system elicits lower basal cytokine mRNA levels and that analysis of cytokine gene expression has the potential to differentiate between non-atopic and atopic individuals.