Analysis of circulating gammadelta T cells in children affected by IgE-associated and non-IgE-associated allergic atopic eczema/dermatitis syndrome

Abstract

Recent studies have suggested that not only alphabeta(+) T cells, but also the less common gammadelta(+) T cells may play a role as effectors and immunoregolatory cells in the development and perpetuation of allergic inflammation. The objective of this study was to focus on the role of gammadelta(+) T cells in atopic dermatitis (AD), a chronic relapsing inflammatory disease of the skin, often associated with allergic bronchial asthma. The present study employed flow cytometric analysis to compare numbers and phenotypic characteristics of gammadelta(+) T cells in the peripheral blood of children with atopic dermatitis and age-matched healthy controls. The percentage of circulating Vgamma 9Vdelta2(+) T lymphocytes was significantly increased in AD patients with respect to the age-matched controls, with a positive correlation with clinical score severity. The prevalent phenotype in both AD patients and controls was CD45RO(+), with no differences observed in the percentage of Vdelta2(+) CD45RO(+) between these groups. Conversely, memory CD45RO(+) CD62L(+) Vdelta2(+) lymphocytes were significantly lower in AD patients. Furthermore, naive circulating Vdelta2(+) T lymphocytes were significantly lower in AD children than in aged-matched controls. No correlation was observed between circulating Vgamma 9Vdelta2(+) expansion and IgE serum levels. It was concluded that an association exists between the levels of circulating gammadelta(+) T lymphocytes and atopic dermatitis, with a positive correlation with clinical score but no link with IgE serum levels. The pathophysiological role of gammadelta T lymphocytes in atopic dermatitis awaits further investigation.

Fig. 1

Peripheral blood mononuclear cells (PBMC) freshly isolated from atopic dermatitis (AD) patients or healthy controls were analysed by flow cytometry for the size of the Vδ2⁺ population. (a) AD patients were grouped altogether or divided into two groups based on clinical score (b). Data shown in (b) revealed significant values only in severe/moderate AD versus mild AD and controls.

Fig. 2

Peripheral blood mononuclear cells (PBMC) freshly isolated from atopic dermatitis (AD) patients or healthy controls (CTR) were analysed for the expression of CD62L/CD45RO markers on the Vδ2⁺ T cell population. The histograms represent a comparison of mean data obtained from 19 AD patients and 15 CTR. Result are represented as mean ± s.d.

Fig. 3

FACS analysis of peripheral blood mononuclear cells (PBMC) from severe or mild atopic dermatitis (AD) patients and healthy controls (CTR). Cells were gated on the Vδ2⁺ T cell population and were analysed for the expression of CD62L/CD45RO markers. Numbers in the boxes indicate the percentage of positive cells within the Vδ2⁺ T cell population. Data are from representative experiments.