house dust mites confer a distinct immunological feature among dermatitis

atopic dermatitis (ad) is a heterogeneous disease with regard to clinical phenotype and natural history. we investigated t cell subtypes and cytokine responses in peripheral blood and skin lesions of ad patients with various sensitivities. immunological studies were performed in 27 subjects: 9 house dust mite (hdm)-sensitized; 6 subjects with sensitizations other than hdm; 7 non-allergic ad patients and 5 healthy controls. among those, skin biopsy samples of 13 subjects were evaluated for immunohistochemical analyses, as well. the mean age was 8.93±5.17 years. hdm-allergic ad emerged as a distinct immunologic phenotype, with higher production of interleukin (il)-4, -5, -2 both at rest and when stimulated by der p1 or seb along with higher th17. as for t h 17 cell percentage, it was increased in all ad groups compared to healthy controls, while hdm-allergic group was distinguished with a significantly lower production of il-17. patients with sensitizations other than hdm were mostly similar to non-allergic ad, with increased th17 and cd4 + cd69 + interferon-gamma (ifn-γ) + t cells percentage. the biopsy of lesional skin showed that hdm-allergic ad had lower ifn-γ and ifn-γ co-expressing cd8 + t cells compared to patients with other sensitizations ( p =0.03 and p =0.04, respectively). among the hdm allergic patients, pairwise comparison of lesional versus non-lesional skin revealed higher cd4 + t cells numbers, expression of forkhead box p3 (foxp3) and t-cell-specific transcription factor (t-bet) ( p =0.018, p =0.018, p =0.018, respectively). hdm-allergic ad is a distinct subtype with a predominant skewing in th2 and higher th17 cell percentage along with a blunted th1 response in the skin, all of which may have therapeutic implications.