Up-regulated cytokine-inducible SH2-containing protein expression in allergen-stimulated T cells from hen's egg-allergic patients

Background: Although changes in the fine balance of allergen-specific T cells are crucial in the pathogenesis of allergic diseases, their roles in the allergic reaction to hen's eggs (HE) have not yet been fully analysed. Objective: Using microarray technology, allergen-stimulated T cells from HE-allergic children were analysed to identify genes that are specifically up-regulated in these cells. Methods: RNA from CD4⁺ CD14^- cells, fractionated from allergen-stimulated peripheral mononuclear cells, was analysed using a whole -genome microarray and real-time RT-PCR. The protein expression of selected genes was ascertained by flow cytometry. Results: In microarray analyses of allergen-stimulated T cells, 43 genes were up-regulated in HE-allergic children but not in non-HE-allergic children. Among these, up-regulation of three genes, cytokine -inducible SH2-containing protein (CISH), nuclear factor of κ light polypeptide gene enhancer in B-cell inhibitor Z (NFKBIZ) and B-cell CLL/lymphoma 2 (BCL2), was confirmed by real-time quantitative RT-PCR. CISH, but not NFKBIZ or BCL2, showed a significantly higher ratio of antigen-stimulated cell transcription over unstimulated cells in HE-allergic than in non-HE-allergic children (P<0.01). Flow-cytometric analysis revealed that the percentage of CD25⁺CISH⁺ cells in CD4⁺ cells from patients with HE allergy was significantly higher than that in controls (P<0.01). The expression level of CISH was significantly higher in IL-4⁺ Th2 cells than in IFN- γ⁺ Th1 cells. Conclusion: We noted that CISH expression in allergen-stimulated CD4⁺ T cells from HE-allergic patients was significantly increased in both mRNA and protein levels compared with that from non-HE-allergic children.