CYTOKINE MESSENGER-RNA EXPRESSION IN CUTANEOUS WARTS - INDUCTION OF INTERLEUKIN-1-ALPHA

The persistence of human papillomavirus at cutaneous sites may be due to impaired trafficking of immune effector cells to the epidermis. We investigated whether HPV infection modulates cytokine mRNA expression in skin, thereby influencing local immunity. The mRNA expression of tu mour necrosis factor-alpha, interleukin-1 alpha (IL-1 alpha), IL-1 bet a, IL-1 receptor antagonist (IL-1ra), IL-4, IL-8, IL-10, IL-12, granul ocyte macrophage colony-stimulating factor, transforming growth factor -beta, interferon-gamma and amphiregulin were assayed in cutaneous war ts and normal skin by semiquantitative reverse transcriptase-polymeras e chain reaction. The expression of the cytokines was heterogeneous in the specimens but, of the 12 mRNA species investigated, only IL-10 mR NA was significantly downregulated in warts compared with normal skin (P = 0.002). IL-1 alpha mRNA expression was significantly upregulated in common warts (P = 0.019) and plantar warts (P = 0.003) compared wit h normal skin. The expression of IL-1 alpha and IL-1ra mRNAs were sign ificantly correlated in plantar warts (P < 0.05). Warts expressing IL- 1 alpha also expressed amphiregulin, and there was a significant corre lation between the expression of these two genes (P < 0.05). It is pos sible that IL-1 alpha expression in cutaneous warts may modulate the g rowth of papillomavirus-infected keratinocytes, mediated by amphiregul in, thus ensuring viral persistence.