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 TH 17 activation. One cluster (n = 6 of 40 consecutive psoriasis patients) indicated a strong TH 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 TH 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 TH 17 polarization and a strong TH 2 component. These results laid the foundation for further demonstrating the pathogenesis of psoriasis in Chinese population.