Our findings show that obesity by itself is not a sufficient condition to alter airway responsiveness to methacholine in a group of adolescents.

The International Study of Asthma and Allergy in Childhood (ISAAC) has assessed the prevalence of asthma, as well as the factors related to the disease in different countries. The aim of this study was to identify asthma risks factors in Mexico City. Data were obtained from questionnaires of children participating in a phase 3b ISAAC survey. Two thousand ninety-eight boys and 2008 girls were recruited in the 6- to 7-year-old group and 3243 boy and 3333 girls were recruited in the 13- to 14-year-old group. Logistic regression was used to determine the asthma risks factors. In the logistic regression for cumulative and current asthma prevalence, the variables allergic rhinitis and atopic dermatitis were the most important risk factors with the highest odds ratios (OR > 1.5; p < 0.05). The use of antibiotics and paracetamol in the first 12 months of life were related to cumulative asthma in both genders in the 6- to 7-year-old group. Contact of pregnant mother with farm animals was positively related with cumulative asthma in boys in the 6- to 7-year-old group. The main factors associated with the cumulative and current prevalence of asthma in both age groups were atopic dermatitis and allergic rhinitis. Future interventions for the prevention and early diagnosis and treatment could be focused in the natural history of the atopic march.

In humans, T cells expressing the CD161 molecule NKR‐P1A constitute around 20% of the circulating CD3+ cells and are potentially immunoregulatory in several diseases. Their role in asthma is not well known, but they could participate in asthma attacks. To determinate whether activation of CD161+ T cells and their cytokine production correlate with clinical status of asthma, we analysed blood samples from asthma attack patients (AAP) and stable asthma patients (SAP) in comparison with healthy non‐atopic controls (HC). There was a significant higher baseline expression of CD69 on T cells from AAP and the difference was more notorious on CD161+ T cells; upregulation of CD69 was observed on both CD161− and CD161+ T cells driven by Dermatophagoides pteronyssinus crude extract, whereas polyclonal stimulation with phorbol 12‐myristate 13‐acetate plus ionomycin predominantly induced IFN‐γ but no IL‐4, IL‐5 and IL‐13 by CD161+ T cells in all groups; upon polyclonal stimulation, there were more CD161+ T cells producing IFN‐γ and less CD161− T cells producing this cytokine, contrasting with the opposite results observed in SAP and HC groups. Our results indicate that, during asthma attack, CD161+ T cells are activated and are able to produce predominantly IFN‐γ but no Th2 cytokines. We hypothesize that during an asthma attack, IFN‐γ produced by CD161+ T cells could help to reestablish the Th1/Th2 equilibrium. These observations may contribute to the understanding of the immune mechanisms involved in asthma attacks.

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Immunomodulation promises to be an effective prophylactic and therapeutic modality for chronic and recurrent respiratory infections. As opposed to vaccines, the term Immunostimulant (IS) refers to a compound that produces a state of non-specific immunity. Most IS are oral formulations of bacterial lysates that have been used in clinical practice for decades. One of the main obstacles in the development of immunostimulants is the poor understanding of the mechanism of action. Except for some compounds the mechanism of action of bacterial products is not well understood. Some appear to act through activation of monocytic cells and macrophages and enhancement of polyclonal proliferation of B cells. In general, the use of IS results in beneficial clinical outcome but the quality of some clinical trials for preventing Acute Respiratory Tract Infections (ARTIs) must be improved. In pediatric