Local nasal immunotherapy for ragweed-allergic rhinitis. III. A second year of treatment

In 1979, pre-seasonal local nasal immunotherapy (LNIT) was found to be an effective treatment for ragweed hay fever. In 1980, this study was continued to evaluate the clinical and immunologic responses of a second year of LNIT. Patients received either pre-seasonal treatment with an unmodified ragweed extract (RW) or a polymerized ragweed extract (PRW), or no treatment. The results of the second year of treatment were the same as the first year. Adverse reactions were significantly higher in the RW-treated group than in the PRW-treated group (P less than 0.001). Symptom/medication scores (SMS) in the RW-treated group were significantly lower than in the control group (P less than 0.005). Although SMS in the PRW-treated group were lower than in the control group, this difference was not significant. The immunologic response was evaluated by measurements of serum (S) RW-specific IgE and IgG and nasal secretory (NS) RW-specific IgE, IgG, and IgA. After treatment, serum IgE titres and secretory IgA titres rose in the RW-treated patients. Nasal secretory-IgG and NS-IgA titres increased with PRW treatment. The only immunologic response observed in the control group was a rise in S-IgE titres after the ragweed season. There was no substantial difference in immunologic measurements observed in the 1979 and 1980 seasons, except that the pre-treatment NS-IgE level was higher in 1980 (P less than 0.02). No significant correlations were found between antibody response and SMS. This study supports the efficacy of LNIT but does not support the protective role for NS-ragweed-specific IgA or IgG.