Temporal patterns of mediator release during developing cutaneous late-phase reactions

Background Several inflammatory mediators have been found released in sites of cutaneous late phase reactions (LPR). However, the temporal pattern of their release during LPR development has not been characterized. Objective Determine hourly accumulation of mediator release in comparison w ith gross and inflammatory cell responses during developing LPR. Methods Skin chamber appended to sites of allergen and diluent control chal lenge with hourly collections. Then, study of exuding leucocytes in chamber bases. Results In the allergen-challenged sites, histamine release peaked in the f irst hour, then low level release over the next 5 h. Lactoferrin release fr om neutrophils started by the second hour, likely associated with released IL-8. Eosinophil cationic protein levels started increasing slightly later. The percentage of exuding leucocytes which were activated was significantl y higher in the allergen challenge sites than in the control challenge site s Conclusions Both gross LPR and local inflammatory cell responses in the ski n start soon after the immediate mast cell activation in IgE-mediated respo nses. Such inflammatory responses include leucocyte activation and mediator release.