Effect of rush immunotherapy in house-dust-mite (HDM)-sensitive adult bronchial asthma: changes in in vivo and in vitro responses to HDM.

An open study was conducted to evaluate the changes in in vivo and in vitro responses to house-dust-mite (HDM) after rush immunotherapy (RI). A 7-day RI protocol using an extract containing HDM allergen was administered to 12 subjects with HDM-sensitive asthma, and the effects on bronchial responsiveness and serum antibody levels were evaluated up to 16 or 20 weeks after RI. The levels of HDM-specific IgG, IgG1 and IgG4 antibodies were significantly elevated from 4 or 8 weeks after RI. Provocative doses causing a 20% fall in FEV1 (PD20) by allergen inhalation were elevated in all subjects at 16 to 20 weeks after RI. There was a high correlation between the increase in log-PD20 and the increase in the ratio of HDM-specific IgG4 to IgG1 (r = 0.68, p < 0.05). The results suggest that RI elicits the improvement of allergen-specific bronchial responsiveness and the increase in serum antibody levels within a relatively short period.