Suppression of the late cutaneous response by immunotherapy

In a prospective, double-blind, placebo-controlled study, we examined the effect of mountain cedar (MC) immunotherapy on the MC-induced late cutaneous response (LCR). Fourteen MC-sensitive patients were intradermally skin tested before and after immunotherapy with MC extract. We measured the size of the wheal at 15 minutes and the area of tissue swelling at 6 hours. Patients were matched by the size of the LCR and started receiving either MC immunotherapy or placebo immunotherapy. MC-specific immunoglobulins (MC sIgG, MC sIgG1, MC sIgG4, and MC sIgE) were measured by ELISA. Symptom-medication scores (SMSs) were recorded on a daily basis during the MC season and tabulated at the end of the study. Comparison of the 14 paired patients revealed no significant differences between MC-treated and placebo-treated groups in preimmunotherapy MC sIgG1 and SIgG4. However, when MC immunotherapy was compared to placebo immunotherapy, patients receiving MC immunotherapy developed significantly higher MC sIgG1 (p less than 0.04) and MC sIgG4 (p less than 0.01) after immunotherapy. Patients receiving MC immunotherapy also demonstrated significantly greater suppression of the LCR after immunotherapy (p less than 0.005) with the postimmunotherapy LCR correlating significantly with both MC sIgG4 (rs = 0.715; p = 0.008) and cumulative dose of MC received (rs = 0.808; p = 0.004). MC sIgE was similar in both groups after immunotherapy. The reduction in SMSs in the MC-treated group did not reach significance, nor was there a correlation of SMSs with MC sIgE, sIgG, sIgG1, or sIgG4.(ABSTRACT TRUNCATED AT 250 WORDS)