Inflammatory cytokine expression in the skin of patients with postherpetic neuralgia

Objective To assess the expression of inflammatory cytokines in the affected and normal skin of postherpetic neuralgia (PHN) patients. Methods Affected skin and normal skin samples were collected from PHN patients. Inflammatory cell infiltration in the dermis were evaluated by hematoxylin-eosin (HE) staining. A human inflammatory protein array containing 40 cytokines was used to assess expression differences between PHN and control skin. Enzyme linked immunosorbent assay (ELISA) kits were used to confirm cytokine expression in 10 PHN patients. Results HE staining showed that the epidermis of PHN skin was thicker than that of contralateral normal skin. Compared with normal skin, there was more infiltration of inflammatory cells into the dermis of PHN skin. The cytokine array detected the presence of 21/40 cytokines; however, only interleukin (IL)-1 alpha showed differential expression between PHN skin and normal skin. ELISA results for IL-1 alpha, IL-16, intercellular adhesion molecule-1, and monocyte chemoattractant protein-1 were consistent with those of cytokine arrays. Conclusions Expression of inflammatory cytokines in PHN skin was not significantly altered compared with normal skin. Chronic refractory pain in PHN is not necessarily associated with increased inflammation in the affected skin.