Pollen-specific rush immunotherapy:: clinical efficacy and effects on antibody concentrations

Background: Studies of rush immunotherapy (RIT) with standardized extracts for the treatment of seasonal pollen allergy are few, especially for birch-pollen RIT. Objective: The study was performed to investigate the efficacy of RIT with standardized birch- or timothy-pollen extracts. Further, the serum antibody levels were evaluated for correlation with clinical efficacy. Methods: This open, longitudinal study included 30 allergic patients treated with RIT and 16 allergic patients serving as a control group. The therapy was continued for 3 years and blood samples were collected at regular intervals for antibody measurements using the Pharmacia CAP System. Results: The RIT was generally well tolerated. An increase in the total and specific IgE concentrations during the early months of RIT was observed, followed by decreased levels. Specific IgG and IgG4 increased continuously for 2 years. The symptom and medication scores were significantly decreased, compared with preRIT, at both the first and third pollen seasons after the start of RIT treatment (P < .0001 and P < .001, respectively). The clinical improvement during RIT was significantly greater compared with the control group (P < .05). The decreased medication and the symptom improvement during the third year of RIT correlated with the relative decrease in specific IgE (r(s) = .52, P < .05) and with the specific IgG4 level before the start of RIT (r(s) = -.68, P < .01), respectively. Conclusions: Our study indicates that RIT with standardized birch- or timothy-pollen extracts is clinically effective and safe. Measurements of specific antibody levels during treatment may be helpful in monitoring RIT.