SUBLINGUAL VERSUS INJECTIVE IMMUNOTHERAPY IN GRASS-POLLEN ALLERGIC PATIENTS - A DOUBLE-BLIND (DOUBLE DUMMY) STUDY

Background Injective immunotherapy is a well-known and recognized trea tment for allergic diseases, but its safety has been questioned during recent years. Alternative administration routes have been proposed an d there is a growing interest and experience in sublingual therapy. Th e safety of alternative routes is nonetheless a real advantage, so lon g as it is not counterbalanced by a loss of clinical benefit. Objectiv e We have compared the efficacy of the same biologically standardized grass pollen extract administered through the injective or the subling ual route, in a group of 20 patients followed for two pollen seasons. Methods Both therapies were administered for 12 months according to a double-blind (double-dummy) plan; at the end of the trial the cumulati ve dosage of the sublingual therapy was 2.4 times higher than that of the injective therapy. Data about skin reactivity, symptoms and drugs scores during the pollen season, as well as total specific IgG and spe cific IgG4, during and after the trial, were obtained. Results Our dat a show that sublingual and injective therapy are equally effective acc ording to subjective clinical parameters, with a statistically highly significant reduction of symptoms and drugs (P = 0.002 for symptoms an d drugs in SLIT-treated patients; P = 0.002 for symptoms and P = 0.003 9 for drugs in patients given injections). On the other hand, objectiv e parameters (total specific IgG, specific IgG4, skin reactivity) chan ged only in patients treated with active injective therapy, with P < 0 .001, P < 0.001 and P = 0.021, respectively. Conclusions The discrepan cies observed could be interpreted as a consequence of different mecha nisms of action of the two therapies or to the lack of close relations hips between the clinical and the objective parameters which were cons idered here.