Bibliographic updates

The Monthly choice - February 2016

Claude MOLINA & Jacques GAYRAUD

1.    Primary prevention of Atopy
2.    Environmental Microbial exposure and Protection against Asthma  
3.    Dog allergen Immunotherapy
4.    Immunologic profile of food allergy in children (egg & peanut)
5.    Upper airway remodeling and Chronic Allergic Rhino-Sinusitis                                                     

1.    Primary prevention of Atopy
Randomized controlled trial with house-dust-mite allergen oral immunotherapy in early childhood: Z.Zolkipli et al JACI Dec.2015 136 6 1541-1547

In 111 infants 5 to 9 months of age at high risk of atopy, with negative prick-tests, drops of high doses HDM active extracts (57 patients) and appropriate placebo solution (54 healthy) were administered orally twice daily for 12 months.        
         
Co-primary outcomes were cumulative sensitization to HDM and to any common allergen during treatment whereas development of eczema, wheeze and food-allergy were secondary outcomes.

The results met the trial’s pre-specified criteria to proof of concept, in reducing sensitization to any allergen. However, no significant preventive effect was observed on allergy related symptoms or HDM sensitization. Further follow-up will determine whether this effect will translate into a reduction in childhood asthma or allergic rhinitis.

2.    Environmental Microbial exposure and Protection against Asthma                                     
P.G Holt and P.D.Sly : NEJM 2015 373 26 2576-78                                     

In a review on the prevention of Asthma, the Australian authors recall the basic research on the atopic component of the disease, the role of microbe-rich animal barn-dust in the natural resistance, the contribution of lipopolysaccharides in this protective effect due to increase in the synthesis of the enzyme A 20, the production of which by airways epithelial cells may implicate it as a potential therapeutic target. Other molecular mechanisms are able to suppress asthma but environmental microbial or viral stimuli are also causal pathways which deserve more investigations.

3.    Dog allergen Immunotherapy                                 
C.A.Coop et al  Annals of A.A.IJan2016 in press
                           
The author performed the published medical literature on the use of dog extracts immunotherapy in patients with hypersensitivity to dogs, taking in account that dogs part of familiar environments of atopic and dog allergens are present in 49% of homes in USA and in Europe. 215 articles, 17 clinical trials were investigated and showed poor and conflicting results of clinical efficacy which has been attributed to poor quality extracts (Canis familiaris f 1 to f 6 ) and the complex allergenic profile that remains without a clearly dominant allergen.

4.    Immunologic profile of Food-Allergy in children (egg and peanut)
-    T.D.Dang1 et al  PAI 2016 27 1 Feb 35-43                                       
-    S.Mayumi et al   PAI 2016 16 Jan  Accepted article   
                          
The 1st Australian article examines changes in peripheral blood of regulatory T cells (Tregs) in 37 infants allergic to egg or peanut, 35 only sensitized and 15 placebo, before and after Oral Food Challenge (OFC).                                              

One hour, then 2 days and 6 days after OFC, non-allergic infants showed stable total Treg frequencies. Food-sensitized a transient fall in Treg percentage with recovery to baseline by day 6. Food-allergic infants showed persistent reduction in Treg with impaired capacity to regenerate the Treg pool, which may be the more important factor that determines clinical allergy versus simple sensitization.

The 2nd Japanese article is a pilot study investigating in 26 children, 5 years of age, with egg allergy the changes in serum the levels of Immunoglobulins (spIgE, subclasses of IgG, IgA) before and after Oral Immunotherapy (OIT) with egg-powder, beginning by a rush phase and during 1 year .
                         
The response to OIT was associated with significant increases of IgG 1 after rush phase and high IgA levels whereas there were small changes in low-responders. This may be useful biomarkers for the prediction of positive clinical response to OIT.

5.    Upper airway remodeling and Chronic Allergic Rhino-Sinusitis                
AO. Eifan et al : AJRCCM 2015 192 1431-1439.     
                    
Testing the hypothesis that upper airway remodeling may account for the chronicity of Rhinosinusitis, like in Asthma, the British authors performed a careful examination of 46 patients suffering from severe CARS (19 control subjects) and nasal biopsies using state of art immune-histology with measurement of classical mediators (e.g; matrix metalloproteinase 9). They showed that tissue remodeling is not a feature of persistent allergic rhinitis. Then, targeting the upper airway remodeling is not an appropriate therapeutic approach. Dietary modifications may offer a non-pharmacologic alternative (Nayan J.et al Journal of Rhinology &Allergy 2015 Nov – Dec 170-174).

Your comments and questions can be sent to:

Claude Molina
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Jacques Gayraud
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Last updated 27 December 2016