A new approach to immunotherapy for house dust mite (D. pteronyssinus) allergy with high dosage of an aluminium adsorbed extract

A group of 50 patients with inhalant sensitivity to the house dust mite (D. pteronyssinus) was selected on a basis of positive history and prick tests or raised total IgE estimation together with positive nasal challenge. D. pteronyssinus was the sole or major allergen for each patient. Prior to the trial, a wider group of patients was given domestic dust avoidance regimens to follow, which produced an adequate symptomatic response in 36.8% of cases. The non-responders to this procedure were offered hyposensitization using standard aluminium adsorbed extracts, together with maintenance therapy, for a total of 12 months, and 89% of them made a good response. The study group in this trial was thus drawn from 7.69% of total attenders, who had failed on all previous treatments. This group was then given a course of an aluminium adsorbed extract ('Norisen', Merck) in a dosage which attained 10,000 PNU on the final dose, and maintenance therapy was given at this level. Thirty-eight (77.5%) of the 49 patients completing the course of treatment showed an excellent or good response and 74% experienced no side-effects. Side-effects which were reported were of similar incidence and severity to those noted on previous allergen treatments. It is suggested, therefore, that higher dosages of extract than that previously recommended should be used in D. pteronyssinus hyposensitivity therapy whenever the diagnosis is well established and there has been an inadequate response to standard measures.