Allergy Immunotherapy for the Reduction of Asthma

The Asthma Severity Score is a customized score created for this study due to the lack of standardized instruments for this age group. It takes into account asthma symptom severity and frequency, as well as asthma medication dosing and potency. Data was collected at baseline and every 2 weeks through interviews conducted over the phone. If the caregiver could not be reached by the phone, the interview was conducted at the next face-to face opportunity (study or injection visit). The minimum score on this scale is 0 (no asthma symptoms and no asthma medicines used during the 14 day interview period). The maximum score is 224 (uncontrolled severe asthma with severe cough, shortness of breath and wheezing on 14 of 14 days, using Albuterol 2 puffs 4x/day, budesonide/formoterol 160ug/4.5ug 2 puffs twice daily and Montelukast 4mg daily on 14 of 14 days). Scores calculated from the collected data were averaged to produce one reported value at baseline and year 1, 2 and 3.

Young children with allergies tend to develop additional environmental allergies over time. This study investigated if allergy immunotherapy could be used to prevent the development of new allergic sensitizations. Participants were tested for sensitivity to a panel of 8 common environmental allergens. Testing was conducted via serum specific immunoglobulin E (IgE) testing. A test was considered negative (non-allergic) if the specific IgE level was <0.35 kIU/L (Kilo International Units/Liter) and positive (allergic) if the levels was >0.35 kIU/L. A "test pair" is the result of a serum IgE test, for a specific allergen, done at two different times. Test pairs can be negative-negative, negative-positive (newly gained allergic sensitization), positive-negative (lost sensitization) or positive-positive. Reported values indicate the total number of newly gained allergic sensitization (negative-positive) for the group.

T regulatory cells are thought to play a role in mediating the effects of immunotherapy in increasing allergen tolerance and dampen the clinical expression of allergy. However, existing studies have not found clear relationship between numbers of T regulatory cells in blood and effect of immunotherapy. The aim of this analysis was to observe potential changes in T regulatory cell numbers in response to immunotherapy in this age group. Peripheral blood cells were acquired and analyzed for T regulatory (Treg) cell markers. In molecular biology, CD4+ (cluster of differentiation 4), a particular cell marker, is a glycoprotein found on the surface of immune cells such as T helper cells and certain groups of T regulatory cells. Testing was done at baseline and then every 12 months. Reported values represents the percentage of CD4+ that are Treg cells.

Any reported use of consequent systemic corticosteroid use due to asthma exacerbation counted as one "corticosteroid burst" (CSB). For example, if a child used 5 days of prednisolone due to asthma exacerbation, this counted as one corticosteroid burst (CSB). An interval of at least 7 days was determined to be necessary to count 2 courses of systemic corticosteroids as separated bursts.

The presented data reflect the intention-to-treat analysis. The time between baseline and each participant's study end time was counted towards the "years in study". The incidence rate describes the number of CSB per child per "year in study".