IL19 and acne: Analysis of independent samples t-test using Mann–Whitney test found statistically significant difference between IL-19 serum concentration of group of patients with mild acne vulgaris and that of group of patients with severe acne vulgaris (p = 0.010) and no significant difference between IL-19 serum concentration of group of patients with mild acne vulgaris and that of group of patients with moderate acne vulgaris (p = 0.312).