RESUMO
BACKGROUND/OBJECTIVES: Psoriasis is one of the immune-mediated inflammatory diseases where CD4+ T lymphocytes, mainly Th1 cells, and B lymphocytes contribute in their pathogenesis through a pro-inflammatory effect, production of antibodies, activation of T cells and cytokine synthesis. B and T lymphocyte attenuator (BTLA) is a co-inhibitory molecule expressed on T and B lymphocytes as well as other immune cells, and it is necessary to inhibit homoeostatic expansion and activation of lymph node and skin-resident γδ T cells. BTLA expression is regulated by RORγt and IL-7. The study aimed at adding more insight on the role played by co-inhibitory molecule BTLA in psoriasis vulgaris and its inter-relation with RORγt and IL-7 to establish a basis for novel treatment strategies. METHODS: This case-control study included 25 patients and 25 controls examined for gene expression of BTLA, RORγt and IL-7. RESULTS: B and T lymphocyte attenuator was significantly lower in psoriasis patients, whereas both RORγt and IL-7 were higher in comparison with controls. A significant positive correlation between disease severity (PASI) and both RORγt and IL-7 as well as between RORγt and IL-7 was found. A significant negative correlation between BTLA and both RORγt and IL-7 was found. Neither the age nor the duration of disease had any correlation with BTLA, RORγt or IL-7. BTLA had no correlation with PASI. Regarding the control group, a significant negative correlation between RORγt and IL-7 was found. CONCLUSION: B and T lymphocyte attenuator, RORγt and IL-7 play an important role in psoriasis.