Claude MOLINA & Jacques GAYRAUD


Comparison of the skin prick-test and IgE to diagnose house-dust mite allergy

Theme: Allergens
Key-words: skin prick tests, specific IgEs, D.Pteronyssinus, D.Farinae

A group of South-Korean ENT specialists (Jung Yong Gi et al :American Journal of Rhinology and Allergy Juin 2010 24 3 226-229), noting that some patients show a discrepancy between skin prick-tests and specific IgEs (by Phadia Immuno Cap), had the idea to compare these two types of test, with 692 subjects suffering from mite allergic rhinitis and to interpret the results according to age  group in order to draw appropriate guidelines.

With 336 D.Pteronyssimus allergic patients, prick-tests appeared more useful than IgEs in detecting allergy for the under-50s (p? 0.0001), whereas for the 350 D.Farinae allergic, specific IgEs were more reliable in all age groups ; however prick-tests on those subjects were less useful for the over-30s (p? 0.0001).

As expected, but it is reassuring to read scientific and statistical confirmation, it is recommended for the diagnosis of over-50 subjects to use specific IgEs (ImmunoCap) rather than skin tests, whereas prick-tests are advised as first choice with the under-30s.

Similarly, attention should be drawn to the recent publication by the American Allergy Academies (Human IgE antibody serology : R.G.Hamilton JACI 126 Juillet 2010 33-38) which indicates a number of variations, around 15%, between results of different procedures of specific IgE detection as available in the US (Phadia, Siemens, Hycor). This could in fact reveal the existence of different populations of IgEs. That is why, in the future, we should not be satisfied with a single biological result but try to obtain information on the test type and several other parameters : among others, antibody concentration,  specific /total IgE ratio, epitope specificity, all factors of ultimately disease expression.


Predicting side effects of immunotherapy to hymenoptera venom

Key-words: bee venom, wasp venom, serum tryptase concentration, specific immunotherapy

A very important multicenter German-Italian-French-Swiss study under the auspices of our eminent colleague, Professor Wutrich  (F.Rueff et al  JACI July 2010  126  1 105_111), reminds us that the VIT initiated in the 1980s and widely recognised for its efficiency may be associated with side effects, some severe and even requiring emergency intervention.
680 patients were enrolled in this prospective study. Its aim was to assess the baseline serum tryptase concentration and other clinical parameters which are routinely recorded during the build-up phase, so as to try to predict the occurrence of these severe reactions : type of VIT (rush or standard procedure), patient’s age, gender, culprit insect (bee or wasp), magnitude of sting reaction, associated cardiovascular medication, venom specific IgEs. All these factors were then statistically treated.

57 patients (8.4%), required an emergency intervention during VIT, a frequency significantly higher in conjunction with a higher serum tryptase concentration. This predictive correlation is higher when VIT was performed for wasp rather than bee venom.
However the other factor significantly associated to side effect severity is bee venom allergy.

In conclusion, before wasp venom VIT, serum tryptase concentration must be measured, a high rate identifying patients with a high risk of side effects.

However experience shows that it is also necessary to carefully monitor patients subject to bee venom immunotherapy.


High burger consumption and child’s asthma risk

Theme : Asthma
Key-words : asthma, diet, hamburger, ISAAC study, ‘Mediterranean’ diet

It is one of the conclusions of the highly-reliable research team of the Epidemiology Institute of Ulm University (Germany) who studied the effect of diet on asthma prevalence and allergic sensitisation with children in the ISAAC international study (G.Nagel Thorax 2010 65 516-522).

Thus, between 1995 and 2005, studies were carried out in 29 centres in 20 European countries on 50 004 school children aged 8 to 12 ; with half of them (29 579) skin prick testing for usual allergens was performed. Parental questionnaires were used to collect information on diet and allergy.

The conclusions are as follows: fruit intake is statistically associated with low prevalence of asthma wheeze, in affluent as well as other countries. The same is true of fish consumption in affluent countries and cooked green vegetables in non-affluent countries.

However overall, high burger consumption was associated with high lifetime asthma prevalence, a prevalence much lower with fruit, green and fish consuming subjects.

It should be noted that none of the food items was associated with allergic sensitisation. Nor with atopic wheeze, except for fruit or fruit juice consumption.

On the whole the so-called ‘Mediterranean’ diet is associated with low prevalence of wheeze and asthma.

As a conclusion diet may be associated with asthma or asthma-like wheezing, regardless of any allergic sensitisation. These results speak strongly in favour of  the protective role against asthma, of a reasonable, balanced diet, rich in fruit and vegetables and low in meat : the ‘Mediterranean’ diet.


Pediatric asthma emergency visits and atmospheric pollution

Theme: Asthma
Key-words: child asthma, air pollutants, ozone

It is well-known that some air pollutants are responsible for asthma exacerbations in children. However this new survey conducted by several teams of the University of Atlanta (US) is an attempt to specify the lag between daily pollutant concentration and symptom emergence, by collecting paediatric asthma emergency department visits and/or admissions, identifying one or more of the main culprit pollutants, measuring their concentrations and appreciating the dose-response effect (M.Strickland et al AJRCCM 2010 182 307-316).

Thus in 1993-2004, 91 386 admissions or consultations by children aged 5-17 in 41 Atlanta area hospitals were counted, while at the same time the concentrations in gaseous and particulate pollutants were measured by urban stationary monitors with rate ratios adapted to the warm (May to October) and the cold (November to April) seasons. The data was subjected to Poisson generalised linear models in the framework of a cross-over analysis.

Results show that Ozone on the one hand, and primary pollutants from traffic sources (SO², NO, NO², CO) on the other, are directly and independently associated with asthmatic children’s consultations and emergency hospital admissions. Their effects are most blatant on the very day of their presence in the ambient atmosphere, even in low concentration.

Thus these pollutants are harmful for the asthmatic child, and quite rapidly, even when concentrations are low. This serious information should be taken into consideration by public health officials and all practitioners.

The harmful role of ozone is further underlined, in the same journal  (M.Stafoggia et al AJRCCM 2010 182 376-384), with elderly and vulnerable subjects (women, diabetics), by an inter-regional Italian team who reveal high mortality rates within this type of population, mainly from respiratory and cardiac diseases.


IgE sensitisation to Aspergillus and lung function in asthma

Theme: Asthma
Key-words: Aspergillus, aspergillosis, asthma, Aspergillus-specific IgE, sputum neutrophils

Allergic broncho-pulmonary aspergillosis (ABPA) is well-known as a frequent complication of ancient asthma ,characterized by a dual sensitisation ( IgE and IgG precipitating antibodies) , but all the biological and clinical consequences of the colonisation of  asthmatic  airways by Aspergillus are less clear.

An English team from Leicester lead by A.Fairs (AJRCCM 2010 16 July a.o.p) therefore undertook research on 79 asthmatic subjects classified into 3 groups: (1) IgE-sensitised (skin tests ?3mm and IgE?0.35 kU/L), (2)IgG-only-sensitised ( IgG ?40 mg/L) and (3) non-sensitised. These were compared to 14 healthy controls. Sputum culture towards detection of Aspergillus in all those patients was compared with clinical assessment data.

Results are as follows :

Culture was positive in 40 subjects from group 1 (IgE-sensitised) i.e. 63%, 13 of group 2 (IgG only) i.e. 39%, 26 of group 3 (non-sensitised) i.e. 31%, and 7% of controls.

Sensitised patients all had  lung function lower than the non-sensitised ones (post-bronchodilator FEV1 68% versus 88% of the predicted value), p?0.05 ; they also had more bronchiectasis (68% versus 35%)  p?0.05 and more sputum neutrophils (80.9% versus 49.5% p?0.01).

In a multilinear regression model, IgE sensitisation to Aspergillus and sputum neutrophil count are important predictors of lung function (p=0.016), followed by fungus culture and eosinophil cell count in sputum.

In conclusion, Aspergillus detection in asthmatics’ sputum is statistically associated with an IgE sensitisation,  neutrophilic airway inflammation and reduced lung function, with permanent airway fixed obstruction therefore appearing as a damaging effect of fungus colonisation.



Source:  CEFCAP
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