Exogenous topical lactoferrin inhibits allergen-induced Langerhans cell migration and cutaneous inflammation in humans

Background Lactoferrin (LF), an iron-binding protein found in exocrine secr etions, is known to possess antibacterial properties. It has recently been proposed that LF may also influence inflammatory reactions. Objectives To characterize in humans the ability of recombinant homologous LF to inhibit the induced migration of epidermal Langerhans cells (LCs) fro m the skin, a process known to be dependent upon the proinflammatory cytoki nes tumour necrosis factor (TNF)-alpha and interleukin 1 beta and to influe nce cutaneous inflammatory reactions. Methods We investigated the anti-inflammatory properties of LF in human vol unteers. Results Topical exposure to LF 2 h prior to sensitization caused a signific ant reduction in contact allergen (diphenylcyclopropenone, DPC)-induced LC migration from the epidermis as judged by the altered frequency of cells ex pressing either HLA-DR or CD1a determinants. That this reduction was second ary to an inhibition of TNF-alpha production was indicated by the fact that LF failed to influence LC migration induced by intradermal injection of th is cytokine. In approximately 50% of those volunteers who displayed local i nflammation in response to DPC, LF was found to cause a discernible reducti on in the clinical severity of the reaction, associated with reduced infilt ration of inflammatory cells. Conclusions These data demonstrate that LF is able to influence cutaneous i mmune and inflammatory responses, possibly because of an impaired productio n of local proinflammatory cytokines.