THE EFFECT OF IMMUNOTHERAPY ON THE CUTANEOUS LATE-PHASE RESPONSE TO ANTIGEN

Background: This study used the skin chamber model to evaluate prospec tively the effect of immunotherapy (IT) on the cutaneous early and lat e phase response (LPR) to epicutaneous antigen challenge. Methods: Nin e subjects with allergic rhinitis were studied at three time points: b efore starting IT, after 3 months of IT, and after 6 months of IT. Ski n chamber histamine content was measured hourly for it hours, and cell counts performed hourly during hours 6 to 12. An intradermal skin tes t 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 s ignificantly (p < 0.05) decreased both early and LPR shin test reactiv ity and skin chamber histamine for hours 1 to 3, 4 to 6, and 9 to 12. Skin chamber LPR cellular influx decreased significantly (p < 0.05) fo r neutrophils only. Decrease in LPR histamine after 6 months of IT was significantly correlated with both decrease in mononuclear cells (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 re activity, 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 eit her dermal cellular infiltrate or deposition of major basic protein. C onclusion: 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 infil trate at 8 hours.