Comparison between the use of adsorbed and aqueous immunotherapy material in Dermatophagoides pteronyssinus sensitive asthmatic children.

BACKGROUND: dermatophagoides pteronyssinus (Der PI) is the major allergen which causes allergic asthma and perennial rhinitis. The extracts of Der PI may be used in treatment of patients who are unresponsive to pharmacological treatment and avoidance of allergens. The success of immunotherapy (IT) depends on the selection of appropriate patients and allergens as well as a regular follow up.

OBJECTIVE: three different groups of IT materials and a placebo were tested on 34 patients with Der PI sensitive asthma. Clinical evaluations of allergen challenge and in vitro immunologic tests were made on the patients before, on the 6th month and at the end of the second year of IT. The results were compared to the placebo treated group.

RESULTS: there were no significant differences among the groups in regard to age, sex and duration of illness. The time required for reaching the maintenance dose for group I (Alutard), II (APSI retard Ca) and III (Greer ) was 15.40 +/- 0.69, 18.2 +/- 4.0 and 108 +/- 33 weeks, respectively. Even though there was some significant difference between those receiving aqueous IT and the placebo (p < 0.05), there was a greater significant difference between those receiving adsorbed IT and placebo (p < 0.00001). Also there was a significant difference between the I and II groups receiving adsorbed IT. There was no significant difference in the maximum tolerated doses between group I and II (p > 0.05), but significant differences was found between group III and the other two groups (p < 0.05). Specific IgE levels were not changed by IT. There were no differences in the side effects scores among the groups (p < 0.05). The maximum tolerated dose of the diluted skin prick test (DSPT) solution increased significantly after 6 months and two years treatment as compared to the dose before specific immunotheraphy (SIT). Significant differences were found between group III and group I or group II as well as between the groups under treatment and that group given a placebo (p < 0.05). The maximum tolerated dose with the bronchial provocation test (BPT) increased significantly after IT (p < 0.05). The differences between the groups under treatment and that given a placebo were significant (p < 0.05). A significant increase was detected in the levels of the Der PI specific IgG4 after IT (p < 0.01). The difference between the treatment groups and the placebo group was significant. There was a significant difference between group I and the other groups (p < 0. 05) but differences between group II and III was not significant (p > 0.05). No significant correlation was found between (1) spIgE and the symptom medication score (SMS) (2) sp IgE and spIgG4 (3), DSPT and BPT. A significant positive correlation was found between the maximum tolerated dose with DSPT and increase in spIgG4 (r = 0.33, p = 0.046). A negative correlation was found between SMS and spIgG4 (p = 0.012, r = -0.42) after IT.

CONCLUSION: SIT with Der PI is an effective and reliable treatment in allergic asthmatic children. Adsorbed extracts may be preferable to in childhood because of effectively, safety, tolerability and, fewer numbers of injection. The best IgG4 response and velocity of maintenance doses achieved was found in group I. Easy, cheap and safe parameters such a SMS and DSPT can be useful for a follow-up of SIT. Further investigation is required to determine which one of the products is the best.