Discipline of Dermatology, Bosch Institute, The University of Sydney at Sydney Cancer Centre, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia.
Br J Dermatol. 2012 Sep;167(3):631-6. doi: 10.1111/j.1365-2133.2012.11109.x.
The immune suppressive effects of topical photodynamic therapy (PDT) are potential contributors to treatment failure after PDT for nonmelanoma skin cancer. Nicotinamide (vitamin B(3) ) prevents immune suppression by ultraviolet radiation, but its effects on PDT-induced immunosuppression are unknown.
To determine the effects of topical and oral nicotinamide on PDT-induced immunosuppression in humans.
Twenty healthy Mantoux-positive volunteers received 5% nicotinamide lotion or vehicle to either side of the back daily for 3 days. Another group of 30 volunteers received 500 mg oral nicotinamide or placebo twice daily for 1 week in a randomized, double-blinded, crossover design. In each study, methylaminolaevulinate cream was applied to discrete areas on the back, followed by narrowband red light irradiation (37 J cm(-2) ) delivered at high (75 mW cm(-2) ) or low (15 mW cm(-2) ) irradiance rates. Adjacent, nonirradiated sites served as controls. Delayed-type hypersensitivity (Mantoux) reactions were assessed at treatment and control sites to determine immunosuppression.
High irradiance rate PDT with vehicle or with placebo caused significant immunosuppression (equivalent to 48% and 50% immunosuppression, respectively; both P < 0·0001); topical and oral nicotinamide reduced this immunosuppression by 59% and 66%, respectively (both P < 0·0001). Low irradiance rate PDT was not significantly immunosuppressive in the topical nicotinamide study (15% immunosuppression, not significant), but caused 22% immunosuppression in the oral study (placebo arm; P = 0·006); nicotinamide reduced this immunosuppression by 69% (P = 0·045).
While the clinical relevance of these findings is currently unknown, nicotinamide may provide an inexpensive means of preventing PDT-induced immune suppression and enhancing PDT cure rates.
光动力疗法（PDT）的免疫抑制作用是导致非黑素瘤皮肤癌 PDT 治疗失败的潜在因素。烟酰胺（维生素 B(3)）可预防紫外线辐射引起的免疫抑制，但它对 PDT 诱导的免疫抑制的影响尚不清楚。
确定局部和口服烟酰胺对人类 PDT 诱导的免疫抑制的影响。
20 名 Mantoux 阳性志愿者背部两侧分别接受 5%烟酰胺洗剂或赋形剂，每天 1 次，连续 3 天。另一组 30 名志愿者以随机、双盲、交叉设计的方式每天口服 500mg 烟酰胺或安慰剂两次，持续 1 周。在每一项研究中，志愿者背部涂抹甲氨基酮戊酸乳膏，然后用窄带红光照射（37 J cm(-2)），分别以高（75 mW cm(-2)）和低（15 mW cm(-2)）辐照度进行照射。相邻的未照射部位作为对照。在治疗和对照部位评估迟发型超敏反应（Mantoux）反应，以确定免疫抑制情况。
高辐照度率 PDT 联合赋形剂或安慰剂均引起明显的免疫抑制（分别相当于 48%和 50%的免疫抑制，均 P < 0·0001）；局部和口服烟酰胺分别使这种免疫抑制降低了 59%和 66%（均 P < 0·0001）。在局部烟酰胺研究中，低辐照度率 PDT 没有明显的免疫抑制作用（15%的免疫抑制，无显著意义），但在口服研究中引起 22%的免疫抑制（安慰剂组；P = 0·006）；烟酰胺使这种免疫抑制降低了 69%（P = 0·045）。
虽然这些发现的临床相关性目前尚不清楚，但烟酰胺可能提供一种廉价的方法来预防 PDT 诱导的免疫抑制并提高 PDT 的治愈率。
