Objectives: The immunological aspects of inflammatory acne are still incompletely understood, so this study aimed to investigate the possible role of IL‐17 and 25 hydroxycholecalciferol (25(OH)D3) in the disease pathogenesis and progression. Materials and Methods: Across‐sectional study has been conducted on 135 patients with active acne vulgaris of various severities and 150 matched controls. ELISA assays of serum and tissue levels of IL‐17 and 25(OH)D3, also immunohisto- chemical and Western blotting demonstration of the expression patterns of lesional IL‐17 in comparison with control group, were performed.
Results: The mean serum levels of IL‐17 were 544.2 pg/mL ± 477.4 SD and 42.2 pg/mL ± 8.1 SD for acne patients and controls, respectively, with significantly higher levels among the patient group (P < 0.05). Higher IL‐17 expression levels in active acne lesions when compared with its level in healthy skin of the controls. The mean serum levels of 25(OH)D3 among patients and controls were 33.3 ng/ mL ± 9.7 SD and 51.7 ng/mL ± 2.7 SD, respectively, with significantly lower levels among the patient group (P < 0.05). There were significantly negative correlations between IL‐17 and 25(OH)D3 levels (P < 0.001 for both).
Conclusions: Deficiency of vitamin D3 accompanied with higher IL‐17 in an inverse
pattern may have a possible role in active acne vulgaris.