Asthma in children and adolescents: knowing more to treat better

Abstract

Asthma is the most common chronic pulmonary disease in children. Notwithstanding, clinical history, age of onset, associated factors as well as the response to multiple treatments are variable. These facts support the need of local studies to better characterize asthma, aiming to check which observations are reproducible or no1. Despite the large number of studies carried out in our environment, there is still some doubts to be solved. Is the prevalence of asthma increasing all over the country? Can asthma risk factors identified in some locations be generalized? Can the exposure to different environmental factors or risk situations intervene in the clinical expression and magnitude of asthma? Is there any genetic marker able to identify patients with more severe forms and with more need of therapeutic care? Can any food be identified as an etiological factor for allergic asthma? Does obesity-associated asthma determine a greater inflammatory process and therefore, poorer asthma control? Is pulmonary function assessed in the beginning of life predictive of asthma development in recurrent wheezing infants? This studies will be conducted through different casuistic and methods. To evaluate the evolution of asthma prevalence in adolescents (13 and 14 years old), the protocol of the International Study of Asthma and Allergies in Childhood (ISMC) will be applied in ten centers that had previously taken part in ISMC Phase 3, seven years ago. A sample of these adolescents will be asked to answer a complementary questionnaire to identify asthma-associated risk/protection factors; they will also be submitted to skin prick test to aeroallergens for allergic etiology identification. In children from different socioeconomic conditions and exposed to enteroparasitosis (Belém, Recife and Montes Claros) the same instruments will be used to identify possible asthmatics. Furthermore, complementary questionnaire, proctoparasitological stool test, determination of serum IgE-specific to inhaled allergens, serum specific IgG1 to Ascaris lumbricoides and serum specific IgG4 to A. lumbricóides will be carried out. Among asthmatic patients followed-up in specialized centers the following evaluations will be performed: genetic polymorphisms studies of tumoral necrosis factor-alpha, transforming growth factor-beta, beta-adrenergic receptors, interleukin (IL)-6, IL-10, gamma interferon, Toll-like receptors 4, 7 e 8, CD14 and HLA-G, as well as in their biological parents. To check the potential role of food allergens as etiological agents for asthma, patients with asthma, patients with food allergy, and patients with asthma plus food allergy will be evaluated for serum specific antibodies or allergen cross-reactivity through an immunofluorometric assay (ImmunoCap-ISAC - Immuno Solid-phase Allergen Chip). Among obese asthmatic adolescents the oxidative stress will be evaluated by the determination of the lipidic profile, triglyceride, HDL-c, LDL-c levels, malondialdeid, supersensible C-protein reactive, retinol, beta-carotene and licopene and the overall glucose tolerance test with glucemia doses that will be compared to the obese adolescents. Among recurrent wheezing infants pulmonary function and exhaled nitric will be performed. During a one year follow-up these infants will be classified as asthmatic or no and correlation between the evaluated parameters will be established. (AU)