Identification of a TH2‐high psoriasis cluster based on skin biomarker analysis in a Chinese psoriasis population

Background Psoriasis is an immune‐mediated, chronic inflammatory disease with diverse phenotypes. However, its biological diversity has not been well‐characterized in Chinese psoriasis population. Objectives To characterize psoriasis biological heterogenicity using gene expression profiles of lesional skin biopsy specimens in a Chinese psoriasis population. Methods Lesional tissues and blood samples from Chinese psoriasis patients ( n = 40), atopic dermatitis (AD) patients ( n = 25) and age‐matched healthy controls ( n = 19) were investigated by using real‐time PCR array, histological evaluation and flow cytometry. Unsupervised hierarchical clustering was performed using gene expression profiles of patients with psoriasis. Results Two distinct psoriasis clusters were identified. Both clusters indicated high T H 17 activation. One cluster ( n = 6 of 40 consecutive psoriasis patients) indicated a strong T H 2 component in skin lesions, with early onset and low peripheral blood eosinophil level. Significantly higher IL‐4 , IL‐13 , IL‐25 , IL‐31 and TSLP gene induction typified this cluster of psoriasis patients, even compared with AD patients. Both psoriasis clusters were characterized by neutrophilic microabscess formation. Histologically, the T H 2 high psoriasis cluster indicated a low percentage of perivascular eosinophils. Conclusions Two distinct psoriasis clusters were identified. One presented early onset and a low eosinophil level, indicating T H 17 polarization and a strong T H 2 component. These results laid the foundation for further demonstrating the pathogenesis of psoriasis in Chinese population.