Heterogeneity in expression of cytokine mRNA in freshly isolated peripheral blood eosinophils of patients with cutaneous-disease-associated eosinophilia.

BACKGROUND

It is thought that there are subpopulations of eosinophils concerning cytokine production: some of them predominantly produce Th1 cytokines, while others produce Th2.

METHODS

By semiquantitative RT-PCR, the in vivo levels of the cytokine mRNA were measured in freshly isolated eosinophils and peripheral blood mononuclear cells (PBMCs) of 19 patients with eosinophilia, including 6 with atopic dermatitis, 4 with drug eruption, 1 with chronic dermatitis, 2 with erythroderma, 3 with bullous pemphigoid, 1 each with urticaria, adult T cell lymphoma, and hypereosinophilic syndrome, and 7 healthy individuals. Eosinophils and PBMCs were isolated by centrifugation over Ficoll-Paque and magnetic cell separation using anti-CD16 antibody.

RESULTS

The IL-4/IFN-gamma ratio in eosinophils as well as PBMCs was increased and correlated well with IgE levels in atopic dermatitis. In other cytokines, such as IL-8, TNF-alpha and TGF-beta1, the levels of mRNA expression were variable among each sample.

CONCLUSION

Not only helper T lymphocytes but also eosinophils may take part in the pathogenesis of cutaneous diseases by virtue of heterogeneity of Th1 and Th2 cytokine production.