RESUMEN
In spite of the existence of numerous scientific studies on the beneficial effect of immunotherapy with specific allergens in the treatment of allergic diseases, their results have not been easily accepted as the methodology and the valuation of the studies have been very heterogeneous. Over the last few years the meta-analysis technology has been developed as a useful tool to globally value the results on the different research studies related to a specific problem. When meta-analyse are carried out correctly, they are accepted as an optimum way to express the results obtained from the different studies from a common view point. In 1995 Abramson MJ, Puy RM and Weiner INI published the first meta-analysis on the efficiency of immunotherapy with specific allergens in the treatment of asthma. The same authors continued to carry out systematic reviews of this theme, and their results were published in the Cochrane Library Document. In october 1999 the latest meta-analysis on immunotherapy in asthma, also carried out by Abramson et al was published in Allergy. In this study 62 investigations published from 1954 to 1998 were included. None of the meta-analyses published to date have separately analysed the studies carried out on children, nor have special considerations been made with respect to the 105 patients who were of paediatric age. The first meta-analysis studies, as well as the ones carried out in 1999, only value random clinical tests, in which there is a valuation of the evolution of asthma and in which mite, pollen, animal, fungi or epithelial allergenic vaccinations are used. Only the subcutaneous administration of the vaccine was allowed. Although this meta-analysis has not been designed to obtain specific conclusions of the effectiveness of immunotherapy in children, probably of conclusions of some of the sections can be applied to the children and/or adolescent population. The authors point out, by valuing the results of the effect of immunotherapy on the clinical evolution, that the studies carried out on children were more homogenous than on adults, which means that their significance on this population is more important. Approximately 50% of the studies that evaluate the clinical evolution, the medicines taken and the specific BHR study with allergens, included children and/or adolescents. It is very probable that these conclusions can be applied to the population between 5 and 18 years old that suffer from allergic asthma, but it is clear that a meta-analysis of the efficiency of immunotherapy in paediatrics is needed. Recently regulations on immunotherapy have been published that appeared after the immunotherapy experts from the World Health Organisation met in Geneva in 1997 (1). The recommendations for immunotherapy in children are clear and similar to those applied to adults: 1. Rhonoconjunctivitis and allergic asthma mediated by IgE. 2. Serious anaphylactic reactions caused by hymenoptera bites. 3. The same diagnosis and treatment considerations recommended are applied to children as well as adults. It is not indicated for allergies to food substances and atopic dermatitis. The patients age is another factor to be considered and, except in the case of allergy to hymenoptera poison, when the patient is under 5 it is a relative counter indication to administer immunotherapy. In general it is admitted that immunotherapy is more efficient on children than on adults, but more studies need to be carried out on the efficiency and safety on children under 5. The early treatment with immunotherapy in children who suffer from allergic respiratory illnesses can have an important significance, as this type of treatment could have a preventive nature as it prevents the rhinitis developing into asthma, as well as the beneficial effect that has been shown on children with allergic asthma.