Long-term immunotherapy with an optimal maintenance dose of a standardizedDermatophagoides pteronyssinus extract in asthmatic patients

In a previous dose-titration study of specific immunotherapy (SIT) with a D ermatophagoides pteronyssinus extract in asthmatic patients, we proposed a dose of 3.2 mu g of Der p and 1/1.6 mu g of Der p 2 as an optimal maintenan ce dose. Changes presented by a high-dose immunotherapy group, with a maxim um tolerated dose between 4 and 16 mu g Der p 1, were compared with those o f a conventional immunotherapy group, with a maximum tolerated dose of 3.2 mu g Der p 1 or lower. After 2 years of SIT; both groups achieved the same level of clinical benefit. We now present the results of long-term monitori ng of 25 of these patients, covering the 5 years of SIT in which the mainte nance dose was set at 3.2 mu g Der p 1. The aims of the study were firstly to examine if this maintenance dose could sustain the changes induced by im munotherapy in the first 2 years; and secondly, to determine if this dose i s clinically effective in patients known to tolerate higher maintenance dos es. The clinical severity index (CSI), medication and symptom scores, cutan eous sensitivity and specific IgE and IgG4 to D, pteronyssinus, Der p 1 and Der p 2 were measured. Positive clinical and immunological changes present ed in the first 2 years of SI-T were sustained(CSI, medication score, speci fic IgE) or even increased (symptom score, cutaneous sensitivity) after 3 a dditional years of SIT In conclusion, a maintenance dose of 3.2 mu g of Der p 1/1.6 mu g of Der p 2 induced intense clinical and immunological changes which were sustained during a 5-year course of treatment, even in patients able to tolerate higher doses.