Evaluation of selected mechanisms of immune tolerance in psoriasis

Introduction
Psoriasis is an autoimmune disease with an excessively aberration of the Th17/Treg balance and deficiency of anti-inflammatory cytokines.

Aim
Evaluation of Treg markers expression in the lesional and perilesional psoriatic skin and serum anti-inflammatory cytokines in male psoriatic patients compared to healthy men.

Material and methods
Treg markers (FoxP3+, CD4, CTLA-4, CD25/IL-2R, CD39/ENTPD1, IL-7R/CD127, CD3) and tissue expression of protective cytokines (IL-10, IL-35, TGF-β) in the lesional and perilesional psoriatic skin from 33 male patients compared to 6 healthy skin samples were evaluated by immunohistochemistry. ELISA was used to assess serum IL-10, IL-35 and TGF-β levels.

Results
The serum levels of IL-35, IL-10 and TGF-β1 were higher in psoriatic patients than in controls but without any statistically significant relationship with PASI. The expressions of IL-35, CD4, IL-10, TGF-β1, CD3, FOXP3 and CD25/IL-2R were varied in different experimental groups (p < 0.05). The level of IL-35 was the lowest in psoriatic lesions (p < 0.05) compared to perilesional skin and to controls. CD4, IL-10 and TGF-β1 expressions were higher (p < 0.05) in perilesional skin than in lesions. TGF-β1 expression was decreased in psoriatic lesions compared to controls (p < 0.05). CD25/IL2R expression was increased in healthy skin compared to psoriatic skin (p < 0.05). FOXP3 expression was elevated in psoriatic skin compared to healthy and perilesional one. There was no difference between experimental groups in CTLA-4, IL7R/CD127 and CD39/ENTPD1 expression.

Conclusions
The differences between the levels of protective cytokines and expression of Treg markers might explain the inflammation development in psoriasis.