Atopic and nonatopic IgE-mediated allergy: a new interpretation of old facts?

Coined 80 years ago, the term 'atopy' to designate a group of diseases associated with IgE and a hereditary background has raised many discussions. In particular, it is difficult to consider as part of an atopic syndrome cases of IgE-mediated allergies to isolated allergens without evidence of a familial inheritance. The postulate expressed in this essay is that in humans we are essentially dealing with an atopic IgE-mediated allergy, which is the equivalent of a genetically determined high IgE response, and with a nonatopic IgE-mediated allergy, which is the equivalent of a low IgE response in mammals and rodents.     

Feeding difficulties in children with non–IgE-mediated food allergic gastrointestinal disorders

ObjectiveTo review the signs and symptoms of feeding difficulties in children with non–IgE-mediated food allergic gastrointestinal disorders and provide practical advice, with the goal of guiding the practitioner to timely referral for further evaluation and therapy. Various management approaches are also discussed.Data SourcesArticles and chapters related to normal feeding patterns and the diagnosis and management of feeding difficulties in children were reviewed.Study SelectionsSelections were based on relevance to the topic and inclusion of diagnostic and management recommendations.ResultsBecause most non–IgE-mediated food allergic gastrointestinal disorders occur in early childhood, feeding skills can be disrupted. Feeding difficulties can result in nutritional deficiencies, faltering growth, and a significant impact on quality of life. Specific symptoms related to each non–IgE-mediated food allergic gastrointestinal disorder can lead to distinctive presentations, which should be differentiated from simple picky eating. Successful management of feeding difficulties requires that the health care team views the problem as a relational disorder between the child and the caregiver and views its association with the symptoms experienced as a result of the non–IgE-mediated food allergic gastrointestinal disorder. Addressing the child's concern with eating needs to be done in the context of the family unit, with coaching provided to the caregiver as necessary while ensuring nutritional adequacy. Treatment approaches, including division of responsibility, food chaining, and sequential oral sensory, are commonly described in the context of feeding difficulties.ConclusionA multidisciplinary approach to management of feeding difficulties in non–IgE-mediated food allergic gastrointestinal disorders is of paramount importance to ensure success.     

High prevalence of lupin allergy among patients with peanut allergy: Identification of γ-conglutin as major allergen

BackgroundLupin is a protein-rich legume with a growing presence in the food market worldwide. With increased consumption, lupin allergy (LA) reports are also rising. Uncertainties exist on the cross-reactivity between peanut and lupin, the allergenic potential of different lupin species, and sensitization patterns among different populations.ObjectiveTo evaluate the molecular basis of LA and to determine lupin allergens from 3 different species that may be involved in peanut allergy (PA) cross-reactivity.MethodsA total of 43 subjects with PA, those with LA, or controls without food allergy were evaluated with skin prick tests (SPTs) and specific IgEs (sIgEs). Lupin-sensitized subjects were offered a lupin oral food challenge (OFC). Immunoblots and enzyme-linked immunosorbent assays were performed on sera from lupin-sensitized subjects.ResultsIn this study, 44% of the PA subjects were confirmed to have LA by OFC. Anaphylaxis was the most frequent manifestation after lupin consumption, with a minimal eliciting dosage of 1 g lupin flour. There was no difference in lupin sIgE or SPT wheal size between lupin-sensitized and confirmed LA subjects or in the severity of symptoms among confirmed LA subjects. Sera from lupin-sensitized subjects uniformly reacted to all 3 different lupin species. Immunoblotting and enzyme-linked immunosorbent assays revealed immunoglobulin E binding to α- and γ-conglutin in all analyzed sera, whereas α- and β-conglutin recognition was variable.ConclusionOur findings reveal a high prevalence of LA among PA subjects, emphasizing lupin must be labeled as an allergen in foods. Owing to high variability in lupin-sIgE and lupin-SPT results, LA diagnosis may require OFC. In our population, γ-conglutin is the major allergen of lupin.     

Food allergy—From food avoidance to active treatment

The prevalence of food allergy (FA) has increased too rapidly, possibly due to environmental factors. The guidelines recommend strict allergen avoidance, but FA is still the main cause of anaphylaxis in all age groups. Immunotherapy is the only treatment able to change the course of allergic disease, and oral immunotherapy (OIT) is the more effective route in FA. However, it carries the risk of adverse reactions, including anaphylaxis. To improve OIT safety, adjuvant therapy with the immunoglobulin E (IgE) monoclonal antibody omalizumab has been extensively used. Results suggest particular benefit in patients with high risk of fatal anaphylaxis. An alternative approach is to use omalizumab instead of OIT to prevent severe allergic reactions upon accidental exposure. This paper reviews current evidence regarding IgE-mediated FA, focusing on natural tolerance and food sensitization acquisition, and on avoidance measures and their limitations.     

Superantigen gene complement of Streptococcus pyogenes—relationship with other typing methods and short-term stability

The profiling of the superantigen (SAg) encoding genes has been frequently used as a complementary typing method for group A streptococci (GAS), but a confusing gene nomenclature and a large diversity of primers used in screening has led to some conflicting results. The aim of this work was to develop a polymerase chain reaction (PCR) method capable of efficiently amplifying all the known allelic variants of these genes, and to evaluate the congruence of this methodology with other commonly used molecular typing methods. The presence of the 11 known SAg genes and two other exotoxin-encoding genes (speB and speF) was tested in a collection of 480 clinical GAS isolates, using two multiplex PCR reactions. The SAg gene profile was compared with other typing methods. Four naturally occurring deletions involving the genes speB, speF, and rgg were characterized, two of which were found among invasive isolates. The absence of the chromosomally encoded genes speG and smeZ was supported by Southern blot hybridization and associated with specific GAS lineages, while the presence of phage-encoded genes was more variable. Positive associations between SAg genes or between SAg profiles and emm types or pulsed-field gel electrophoresis (PFGE) clusters were observed. The results suggest that the SAg profile diversifies faster than other properties commonly used for molecular typing, such as emm type and multilocus sequence typing (MLST) sequence types (STs), and can be a useful complement in GAS molecular epidemiology. Still, the short-term stability of the SAg gene profile among prevalent genetic lineages may largely explain the observed associations between SAg genes.     

Interleukin 10 (IL10) and transforming growth factor β1 (TGFβ1) gene polymorphisms in persistent IgE-mediated cow's milk allergy

OBJECTIVES:

The aim of this cross-sectional study was to evaluate whether interleukin 10 (IL10) and transforming growth factor β1 (TGFβ1) gene polymorphisms were associated with persistent IgE-mediated cow''s milk allergy in 50 Brazilian children. The diagnostic criteria were anaphylaxis triggered by cow''s milk or a positive double-blind, placebo-controlled food challenge. Tolerance was defined as the absence of a clinical response to a double-blind, placebo-controlled food challenge or cow''s milk exposure.

METHOD:

The genomic DNA of the 50 patients and 224 healthy controls (HCs) was used to investigate five IL10 gene polymorphisms (-3575A/T, -2849A/G, -2763A/C, -1082G/A, -592C/A) and one TGFβ1 polymorphism (-509C/T).

RESULTS:

Among the five IL10 polymorphisms analyzed, homozygosis for the G allele at the -1082 position was significantly higher in the patients compared with the healthy controls (p = 0.027) and in the persistent cow''s milk allergy group compared with the healthy controls (p = 0.001).

CONCLUSIONS:

Homozygosis for the G allele at the IL10 -1082G/A polymorphism is associated with the persistent form of cow''s milk allergy.     

Why do hemopoietic growth factor receptors interact with each other?

Hemopoietic growth factors (colony-stimulating factors, CSFs) interact with distinct cellular receptors that recognize only their cognate ligand. Yet, like other growth factor/receptor systems, the binding of one type of CSF to its receptor can ‘down-modulate’ the availability of a different tyoe of CSF receptor. In this article Nicos Nicola discusses the distinctive pattern of] CSF-receptor modulations and suggests a novel interpretation of such modulations as a means of coupling receptor-derived signals which is consistent with the known biology of the system.