House dust mite immunotherapy in asthmatic patients: A randomised, double-blind, placebo-controlled trial

Abstract

Background: Despite it's 100 years of existence, Immunotherapy still has not completely fulfilled it's therapeutic role. In Cuba there have been scarce clinical trials involving this therapeutic approach due the lack of standardized extracts. Method(s): In order to assess the efficacy of house dust mite (HDM) immunotherapy, we started a randomized, double-blind, placebo-controlled trial in patients attending the allergy center of Policlinico Universitario in Previsora Camaguey, province of Cuba. We included 160 both gender asthmatic patients older than 15 years; the standardized HDM extracts for the skin prick test were obtained from an argentinian laboratory, including Dermatophagoides pteronyssinus, Dermatophagoides farinae, Acarus sirus, Lepidoglyphus destructor, Tyrophagus putrescentiae, Glycyphagus domesticus, Chortoglyphus arcuatus and Blomia tropicalis. We also obtained standardized HDM extracts from a cuban laboratory, including Dermatophagoides pteronyssinus, Dermatophagoides siboney and Blomia tropicalis. After informed consent approval, the patients were randomly allocated into two groups: Immunotherapy (IT) and Placebo. In the IT group, patients with a wheal size bigger than 5 mm received a specific subcutaneous vaccine. In the placebo group, patients received a subcutaneous diluting agent. The Asthma Quality of Life Questionnaire (AQLQ) of Juniper was used at the beginning of the study and repeated 12 months later. Statistical Analysis was made using SPSS 11.5 software, comparing the mean difference in the size of the wheals after and before the treatment. Result(s): In the IT group the differences in size of the wheals were statistically significative (P < 0.05), whereas the differences recorded in the placebo group were not (P > 0.05). The mean size of the first measurement of the wheals was 55 833 (IT group) and 53 333 (placebo group) -standard deviation of, 79 296 and, 65 134 respectively-. In the second measurement, we recorded 35 000 for the IT group -standard deviation of, 52 223- and 52 500 for the placebo group -standard deviation of 105 529-. The AQLQ demonstrated that, after 12 months of treatment, the most relevant domain scores included 'symptoms' and 'activity limitation', with a difference of 20 points higher in the IT group compared with the placebo group. Conclusion(s): HDM immunotherapy diminish the symptoms and activity limitation in asthmatic patients, and lessen the size of the wheals.