Serum level of interleukin-22 in patients with cutaneous warts: A case-control study

Warts are viral cutaneous infections caused by human papilloma virus (HPV), presented by verrucous growth over the skin surface. The immune response is considered to play a crucial role in HPV clearance. It depends on intact cellular immunity including natural killer (NK) cell and cytotoxic T cells. It has been clarified that T-helper (Th) 1 cytokines (interleukin (IL)-2, interferon-γ, and tumor necrosis factor-a) and IL-17 are involved in HPV clearance. IL-22 is one of IL-10 family of cytokines produced by NK cells, Th1, Th17, and Th22 cells. In the skin, IL-22 reduces keratinocyte cornification and enhances keratinocyte production of antimicrobial peptides. IL-22 overexpression has been demonstrated in various viral infections and skin inflammatory disorders.

The aim of this study was to assess serum levels of IL-22 in patients with warts and its association with their different clinical characteristics.

The study included 20 patients with warts and 20 control subjects. Serum concentration of IL-22 was measured by enzyme-linked immune sorbent assay.

Serum levels of IL-22 were significantly higher in patients with warts than in control subjects (P < .001). The levels were significantly higher in patients with recurrent warts after prior treatment than in patients with first-time warts (P = .007). Moreover, a significant positive correlation was detected between serum levels of IL-22 and the number of warts (P = .017).

Serum level of IL-22 was elevated in patients with warts. Thus, IL-22 may have a crucial role in the antiviral immune response against this infection.