CD137: A Member of the TNFR Family - in Psoriasis Skin Lesions in Comparison with Normal Skin Specimens

BACKGROUND & OBJECTIVE: CD137 is a member of the TNF-Receptor family. TNF-alpha antagonists have therapeutic effect in active psoriasis. In this study, the relative frequency of CD137 expression was investigated in the inflammatory cells of psoriasis lesions for the first time. METHODS: The specimens were obtained from pathology department of Al-Zahra hospital from paraffin-embedded skin specimens collected from 2007 till 2016. . A total number of f 64 psoriasis skin specimens and 34 normal skin specimens were reviewed for the diagnosis. Then, the immunohistochemical staining for CD137, CD4, and CD8 was performed. RESULTS: CD137 expression of dermal inflammatory cells in psoriasis lesions was 11.19±5.5%. Although, in normal skin tissues, CD137 expression was observed in 1.3±3.03% of the inflammatory cells. (P=0.001). The relative frequency of the CD137 positive inflammatory cells was significantly higher in the epidermis compared to dermis (epidermis: 31.1%±12.8, dermis 11.1%±5.5). There was no remarkable relation between the CD137 expression rate and the CD4: CD8 ratio. CONCLUSION: CD137 as a TNF-alpha receptor has a significant role in pathogenesis of the psoriasis lesions. Therefore, CD137 antagonists can be considered as a novel target for the treatment of incurable psoriasis patients.