The effect of immunotherapy on the cutaneous late phase response to antigen

Abstract Background: This study used the skin chamber model to evaluate prospectively the effect of immunotherapy (IT) on the cutaneous early and late phase response (LPR) to epicutaneous antigen challenge. Methods: Nine subjects with allergic rhinitis were studied at three time points: before starting IT, after 3 months of IT, and after 6 months of IT. Skin chamber histamine content was measured hourly for 12 hours, and cell counts performed hourly during hours 6 to 12. An intradermal skin test was placed, and the reaction was measured hourly for 12 hours. Skin biopsy specimens were obtained 8 hours after intradermal placement and evaluated for cellular infiltrate and major basic protein deposition. Serum antigen-specific IgG and IgE levels were measured at each time point to confirm physiologic effect of IT. Results: Six months of IT significantly ( p p R 2 = 0.817, p = 0.002) and decrease in neutrophils ( R 2 = 0.813, p = 0.009). Also significantly correlated were decrease in LPR skin test reactivity, with percent change in skin chamber mononuclear cells ( R 2 = 0.800, p = 0.009) and decrease in early skin test reactivity ( R 2 = 0.675, p = 0.01). Biopsy specimens showed no consistent change in either dermal cellular infiltrate or deposition of major basic protein. Conclusion: IT significantly attenuates cutaneous histamine release and skin test reactivity and is accompanied by a decrease in skin chamber LPR neutrophil influx without significantly altering the dermal infiltrate at 8 hours.