Identification of alpha-gal sensitivity in patients with a diagnosis of idiopathic anaphylaxis.

IgE antibodies (Ab) specific to galactose-α-1,3-galactose (alpha-gal) are responsible for a delayed form of anaphylaxis that occurs 3-6 hours after red meat ingestion. In a unique prospective study of seventy participants referred with a diagnosis of idiopathic anaphylaxis (IA), six (9%) were found to have IgE to alpha-gal. Upon institution of a diet free of red meat, all patients had no further episodes of anaphylaxis. Two of these individuals had indolent systemic mastocytosis (ISM). Those with ISM had more severe clinical reactions but lower specific IgE to alpha-gal and higher serum tryptase levels, reflective of the mast cell burden. The identification of alpha-gal syndrome in patients with IA supports the need for routine screening for this sensitivity as a cause of anaphylaxis, where reactions to alpha-gal are delayed and thus may be overlooked.

Prospective, comparative effectiveness trial of cow's milk elimination and swallowed fluticasone for pediatric eosinophilic esophagitis.

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated disease in which food antigens play a key role. Current therapeutic options are limited to long-term steroid medication and dietary elimination of multiple foods, each of which is challenging. Our objective was to compare single food elimination of cow's milk to swallowed fluticasone in pediatric EoE patients. This is a prospective, comparative effectiveness trial of newly diagnosed EoE patients (ages 2-18 years) treated with swallowed fluticasone (n = 24) or elimination of cow's milk (n = 20). The dual outcome measures of repeat esophageal biopsy (6-8 weeks) and change in Pediatric Quality of Life Inventor (PedsQL) EoE Module and Symptoms Scales were used to assess response to treatment. After 6-8 weeks of treatment, peak esophageal eosinophil counts decreased to below the threshold of 15 eosinophils/high-power field in 64% of patients treated with cow's milk elimination and 80% of patients treated with swallowed fluticasone (P = 0.4). Mean PedsQL EoE Module total scores (69 vs. 82; P < 0.005) and Total Symptoms scores (58 vs. 75; P = 0.001) showed significant improvement with cow's milk elimination. Among children treated with swallowed fluticasone, mean PedsQL EoE Module total scores (64 vs. 75; P < 0.05) and Total Symptoms scores (58 vs. 69; P < 0.01) were also significantly improved after 6-8 weeks of therapy. Removal of cow's milk from the diet is an effective single food elimination treatment for pediatric patients with EoE as assessed by statistically significant histologic and symptomatic improvement. Cow's milk elimination may be more desirable for EoE patients who do not want to take chronic, long-term steroid medications.

Effects of geohelminth infection and age on the associations between allergen-specific IgE, skin test reactivity and wheeze: a case-control study.

BACKGROUND: Most childhood asthma in poor populations in Latin America is not associated with aeroallergen sensitization, an observation that could be explained by the attenuation of atopy by chronic helminth infections or effects of age. OBJECTIVE: To explore the effects of geohelminth infections and age on atopy, wheeze, and the association between atopy and wheeze. METHODS: A case-control study was done in 376 subjects (149 cases and 227 controls) aged 7-19 years living in rural communities in Ecuador. Wheeze cases, identified from a large cross-sectional survey, had recent wheeze and controls were a random sample of those without wheeze. Atopy was measured by the presence of allergen-specific IgE (asIgE) and skin prick test (SPT) responses to house dust mite and cockroach. Geohelminth infections were measured in stools and anti-Ascaris IgE in plasma. RESULTS: The fraction of recent wheeze attributable to anti-Ascaris IgE was 45.9%, while those for SPT and asIgE were 10.0% and 10.5% respectively. The association between atopy and wheeze was greater in adolescents than children. Although Anti-Ascaris IgE was strongly associated with wheeze (adj. OR 2.24 (95% CI 1.33-3.78, P = 0.003) and with asIgE (adj. OR 5.34, 95% CI 2.49-11.45, P < 0.001), the association with wheeze was independent of asIgE. There was some evidence that the association between atopy and wheeze was greater in uninfected subjects compared with those with active geohelminth infections. CONCLUSIONS AND CLINICAL RELEVANCE: Atopy to house dust mite and cockroach explained few wheeze cases in our study population, while the presence of anti-Ascaris IgE was an important risk factor. Our data provided only limited evidence that active geohelminth infections attenuated the association between atopy and wheeze in endemic areas or that age modified this association. The role of allergic sensitization to Ascaris in the development of wheeze, independent of atopy, requires further investigation.

Prenatal negative life events increases cord blood IgE: interactions with dust mite allergen and maternal atopy.

BACKGROUND: Prenatal exposure to both stress and aeroallergens (dust mite) may modulate the fetal immune system. These exposures may interact to affect the newborn immune response. We examined associations between prenatal maternal stress and cord blood total IgE in 403 predominately low-income minority infants enrolled in the Asthma Coalition on Community, Environment, and Social Stress (ACCESS) project. We also examined potential modifying effects of maternal atopy and maternal dust mite exposure. METHODS: The Crisis in Family Systems survey was administered to mothers prenatally, and a negative life event domain score was derived to characterize stress. Dust mite allergen was quantified in dust from pregnant mothers' bedrooms. Cord blood was analyzed for total IgE. Using linear regression, we modeled the relationship of stress with cord blood IgE and interactions of stress with dust mite and/or maternal atopy, adjusting for potential confounders. RESULTS: Higher prenatal maternal stress (ß = 0.09; P = 0.01) was associated with increased cord blood IgE. The interactive effects between stress and dust mite groups (high vs low) were significantly different for children of atopic vs nonatopic mothers (P for three-way interaction = 0.005). Among children of atopic mothers, the positive association between stress and IgE was stronger in the high dust mite group. In children of mothers without a history of atopy, the positive association between stress and IgE was most evident in the low allergen group. CONCLUSIONS: Prenatal stress was independently associated with elevated cord blood IgE. Mechanisms underlying stress effects on fetal immunomodulation may differ based on maternal atopic status.

Is the hygiene hypothesis still a viable explanation for the increased prevalence of asthma?

The hygiene hypothesis states that a reduced exposure to allergens in early life is solely implicated in the growing propensity for allergy sensitization. Important elements of the hypothesis include helminth infection, exposure to endotoxins, exposure to pets and growing up on a farm. However, the hygiene hypothesis alone does not provide an adequate explanation for the observed increase in allergic disease. For example, in North American inner cities, asthma is increasing among children who live in very poor housing, which might be assumed to be somewhat dirty. In order to explain the increase in asthma, we need to take a broader view and also consider alterations related to the adoption of a western lifestyle. It has been suggested that lifestyle changes related to obesity (e.g. a change in diet) are associated with asthma. Other changes include a progressive decrease in physical activity. This lifestyle factor seems to correlate best with the recent increase in asthma. Clearly, the link between physical activity and asthma needs to be investigated in more detail.