Increased IL-4 and decreased regulatory cytokine production following relocation of Icelandic horses from a high to low endoparasite environment

Insect bite hypersensitivity (IBH) is an IgE-mediated dermatitis of horses caused by bites of Culicoides spp. IBH does not occur in Iceland where Culicoides are absent. However, following importation into continental Europe where Culicoides are present, >or=50% of Icelandic horses (1st generation) develop IBH but

Cloning, production and characterization of antigen 5 like proteins from Simulium vittatum and Culicoides nubeculosus, the first cross-reactive allergen associated with equine insect bite hypersensitivity

Insect bite hypersensitivity (IBH) is an IgE-mediated seasonal dermatitis of the horses associated with bites of Simulium (black fly) and Culicoides (midge) species. Although cross-reactivity between Simulium and Culicoides salivary gland extracts has been demonstrated, the molecular nature of the allergens responsible for the observed cross-reactivity remains to be elucidated. In this report we demonstrate for the first time in veterinary medicine that a homologous allergen, present in the salivary glands of both insects, shows extended IgE cross-reactivity in vitro and in vivo. The cDNA sequences coding for both antigen 5 like allergens termed Sim v 1 and Cul n 1 were amplified by PCR, subcloned in high level expression vectors, and produced as [His](6)-tagged proteins in Escherichia coli. The highly pure recombinant proteins were used to investigate the prevalence of sensitization in IBH-affected horses by ELISA and their cross-reactive nature by Western blot analyses, inhibition ELISA and intradermal skin tests (IDT). The prevalence of sensitization to Sim v 1 and Cul n 1 among 48 IBH-affected horses was 37% and 35%, respectively. In contrast, serum IgE levels to both allergens in 24 unaffected horses did not show any value above background. Both proteins strongly bound serum IgE from IBH-affected horses in Western blot analyses, demonstrating the allergenic nature of the recombinant proteins. Extended inhibition ELISA experiments clearly showed that Sim v 1 in fluid phase is able to strongly inhibit binding of serum IgE to solid phase coated Cul n 1 in a concentration dependent manner and vice versa. This crucial experiment shows that the allergens share common IgE-binding epitopes. IDT with Sim v 1 and Cul n 1 showed clear immediate and late phase reactions to the allergen challenges IBH-affected horses, whereas unaffected control horses do not develop relevant immediate hypersensitivity reactions. In some horses, however, mild late phase reactions were observed 4h post-challenge, a phenomenon reported to occur also in challenge experiments with Simulium and Culicoides crude extracts probably related to lipopolysaccaride contaminations which are also present in E. coli-expressed recombinant proteins. In conclusion our data demonstrate that IgE-mediated cross-reactivity to homologous allergens, a well-known clinically relevant phenomenon in human allergy, also occurs in veterinary allergy.

Current patch test results with the European baseline series and extensions to it from the 'European Surveillance System on Contact Allergy' network, 2007-2008

The pattern of contact sensitization to the supposedly most important allergens assembled in the baseline series differs between countries, presumably at least partly because of exposure differences. Objectives. To describe the prevalence of contact sensitization to allergens tested in consecutive patients in the years 2007 and 2008, and to discuss possible differences.

Equine insect bite hypersensitivity: immunoblot analysis of IgE and IgG subclass responses to Culicoides nubeculosus salivary gland extract

Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by IgE-mediated reactions to bites of Culicoides and sometimes Simulium spp. The allergens causing IBH are probably salivary gland proteins from these insects, but they have not yet been identified. The aim of our study was to identify the number and molecular weight of salivary gland extract (SGE) proteins derived from Culicoides nubeculosus which are able to bind IgE antibodies (ab) from the sera of IBH-affected horses. Additionally, we sought to investigate the IgG subclass (IgGa, IgGb and IgGT) reactivity to these proteins. Individual IgE and IgG subclass responses to proteins of C. nubeculosus SGE were evaluated by immunoblot in 42 IBH-affected and 26 healthy horses belonging to different groups (Icelandic horses born in Iceland, Icelandic horses and horses from different breeds born in mainland Europe). Additionally, the specific antibody response was studied before exposure to bites of Culicoides spp. and over a period of 3 years in a cohort of 10 Icelandic horses born in Iceland and imported to Switzerland. Ten IgE-binding protein bands with approximate molecular weights of 75, 66, 52, 48, 47, 32, 22/21, 19, 15, 13/12 kDa were found in the SGE. Five of these bands bound IgE from 50% or more of the horse sera. Thirty-nine of the 42 IBH-affected horses but only 2 of the 26 healthy horses showed IgE-binding to the SGE (p<0.000001). Similarly, more IBH-affected than healthy horses had IgGa ab binding to the Culicoides SGE (19/22 and 9/22, respectively, p<0.01). Sera of IBH-affected horses contained IgE, IgGa and IgGT but not IgGb ab against significantly more protein bands than the sera of the healthy horses. The cohort of 10 Icelandic horses confirmed these results and showed that Culicoides SGE specific IgE correlates with onset of IBH. IBH-affected horses that were born in Iceland had IgGa and IgGT ab (p< or =0.01) as well as IgE ab (p=0.06) against a significantly higher number of SGE proteins than IBH-affected horses born in mainland Europe. The present study shows that Culicoides SGE contains at least 10 potential allergens for IBH and that IBH-affected horses show a large variety of IgE-binding patterns in immunoblots. These findings are important for the future development of a specific immunotherapy with recombinant salivary gland allergens.

Evaluation of an in vitro sulphidoleukotriene release test for diagnosis of insect bite hypersensitivity in horses

REASONS FOR PERFORMING STUDY: Insect bite hypersensitivity (IBH) is an IgE-mediated allergic dermatitis caused by bites of Culicoides and Simulium species, and improved means of diagnosis are required. OBJECTIVES: The cellular antigen simulation test (CAST) with C. nubeculosus and S. vittatum extracts was assessed in a population of IBH-affected and healthy horses. Variations in test results over a one year period and possible cross-reactivity between different insect extracts was studied. METHODS: A total of 314 mature horses were studied using the CAST. Influence of severity of clinical signs, gender and age were evaluated, and 32 horses were tested repeatedly over one year. The kappa reliability test was used to assess agreement of the test results with different insect extracts. RESULTS: Horses with IBH had significantly higher sLT release than controls with C. nubeculosus and S. vittatum. The highest diagnostic sensitivity and specificity levels were attained when using adult C. nubeculosus extracts with the CAST (78% and 97%, respectively), suggesting that most horses with IBH are sensitised against Culicoides allergens. A proportion of IBH-affected horses was found to be sensitised to allergens of Simulium spp. in addition to those of C. nubeculosus. The CAST with C. nubeculosus had positive and negative predictive values > or = 80% for a true prevalence of IBH of 12-52%. In the follow-up study, the proportion of IBH-affected horses with a positive test result ranged from 90% in November to 68% in March. Severity of clinical signs or age did not influence test results significantly. However, IBH-affected males achieved significantly more positive test results than IBH-affected females. CONCLUSIONS: The CAST with adult C. nubeculosus has high specificity and good sensitivity for diagnosis of IBH. Horses with IBH are mainly sensitised to Culicoides allergens, and some horses are additionally also sensitised to allergens in Simulium spp. POTENTIAL RELEVANCE: The CAST is likely to be a useful test for diagnosis of IBH, even allowing the identification of IBH-affected but asymptomatic horses. This test may also help in further characterisation of allergens involved in this condition.

Eosinophilic esophagitis in adults--no clinical relevance of wheat and rye sensitizations

BACKGROUND: Eosinophilic esophagitis (EE) is often associated with concomitant atopic diseases. In children with EE in whom food allergens have been identified as causative factors, elemental and elimination diets result in an improvement or resolution of symptoms. Most adult EE patients are sensitized to aeroallergens, which cross-react with plant-derived food allergens, most commonly to grass pollen and cereals. AIMS OF THE STUDY: To investigate the clinical relevance of the sensitization to wheat and rye, and the efficacy of an allergen-specific elimination diet in adult EE patients. METHODS: Six patients (five men, one women) with permanently active EE sensitized to grass pollen and the cereals wheat and rye underwent a double-blind placebo-controlled food challenge and were kept on an elimination diet avoiding wheat and rye for 6 weeks. RESULTS: The challenge tests with wheat and rye did not provoke any EE symptoms in all patients. The elimination diet failed in reducing disease activity. Although one patient noticed an improvement of symptoms, endoscopic and histopathologic findings remained unchanged. CONCLUSIONS: In adult EE patients, sensitization to wheat and rye does not seem causative for EE. Elimination diet is not a reliable and efficient therapeutic measure in EE patients sensitized to wheat and rye. Low specific immunoglobulin-E levels to wheat and rye may be a consequence of the underlying grass pollen allergy.

[Pemphigoid nodularis triggered by hypereosinophilic syndrome?]

Pemphigoid nodularis (PN) is a rare clinical variant of pemphigoid characterized by prurigo-like skin lesions and antibodies against BP180 and BP230 characteristic for bullous pemphigoid. Interestingly, most PN patients never develop blisters. This condition is often resistant to treatment. We describe a female patient who was initially diagnosed with hypereosinophilic dermatitis. Later on, in the presence of eosinophilic infiltrations in the gastrointestinal tract, obstructive ventilation disorder, pericardial and pleural effusions, the diagnosis of idiopathic hypereosinophilic syndrome was made. During the following 3 years she developed recalcitrant PN.

Alterations of exhaled nitric oxide in pre-term infants with chronic lung disease

Animal models suggest that reduced nitric oxide (NO) synthase activity results in lower values of exhaled NO (eNO) present at birth in those individuals who are going to develop chronic lung disease of infancy (CLDI). Online tidal eNO was measured in 39 unsedated pre-term infants with CLDI (mean gestational age (GA) 27.3 weeks) in comparison with 23 healthy pre-term (31.6 weeks) and 127 term infants (39.9 weeks) at 44 weeks post-conceptional age, thus after the main inflammatory response. NO output (NO output (V'(NO)) = eNO x flow) was calculated to account for tidal- flow-related changes. Sex, maternal atopic disease and environmental factors (smoking, caffeine) were controlled for. The mean eNO was not different (14.9 ppb in all groups) but V'(NO) was lower in CLDI compared with healthy term infants (0.52 versus 0.63 nL x s(-1)). Values for healthy pre-term infants were between these two groups (0.58 nL x s(-1)). Within all pre-term infants (n = 62), V'(NO) was reduced in infants with low GA, high clinical risk index for babies scores and longer duration of oxygen therapy but not associated with post-natal factors, such as ventilation or corticosteroid treatment. After accounting for flow, the lower nitric oxide output in premature infants with chronic lung disease of infancy is consistent with the hypothesis of nitric oxide metabolism being involved in chronic lung disease of infancy.

Chemokines indicate allergic bronchopulmonary aspergillosis in patients with cystic fibrosis

RATIONALE: Allergic bronchopulmonary aspergillosis (ABPA) is characterized by a Th2 immune response. Mouse models suggest a critical role for the Th2 chemokines thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) in ABPA. OBJECTIVES: To determine whether serum levels of TARC and MDC characterize ABPA in patients with cystic fibrosis (CF) and to examine longitudinally if levels of TARC and MDC indicate ABPA exacerbations in patients with CF. METHODS: Levels of TARC and MDC and levels of Th1 (IL-12 and IFN-gamma) and Th2 (IL-4, IL-5, and IL-13) cytokines were analyzed in serum of 16 patients with CF with ABPA, six non-CF patients with asthma with ABPA, 13 patients with CF colonized with Aspergillus fumigatus, six patients with CF sensitized to A. fumigatus, 12 atopic patients with CF, and 13 non-CF atopic control subjects by ELISA. The longitudinal course of TARC, MDC, and IgE levels was assessed during ABPA episodes. RESULTS: Patients with ABPA had significantly higher serum levels of TARC compared with the other patient groups. Cytokine levels did not differ among the patient groups. Longitudinally, levels of TARC indicated ABPA exacerbations in patients with CF more clearly than IgE levels. In patients with CF and ABPA, levels of TARC correlated positively with specific IgE to A. fumigatus and rAsp f4. CONCLUSIONS: Serum levels of TARC differentiate patients with CF or patients with asthma with ABPA from patients with CF colonized with or sensitized to A. fumigatus, atopic patients with CF, and atopic control subjects. Longitudinally, levels of TARC indicate ABPA exacerbations, suggesting TARC as a marker for identification and monitoring of ABPA in patients with CF.

Reduced incidence of insect-bite hypersensitivity in Icelandic horses is associated with a down-regulation of interleukin-4 by interleukin-10 and transforming growth factor-beta1

Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by IgE-mediated reactions to bites of insects of the genus Culicoides. IBH does not occur in Iceland due to the absence of Culicoides. However, Icelandic horses exported to mainland Europe as adults (1st generation) have a >/=50% incidence of developing IBH. In contrast, their progeny (2nd generation) has a <10% incidence of IBH. Here we show that peripheral blood mononuclear cells (PBMC) from Icelandic horses born in mainland Europe and belonging either to the IBH or healthy subgroup produce less interleukin (IL)-4 after polyclonal or allergen-specific stimulation when compared with counterparts from horses born in Iceland. We examined a role of IL-10 and transforming growth factor (TGF)-beta1 in down-regulation of IL-4 in healthy 2nd generation Icelandic horses. Supernatants of PBMC from 2nd generation healthy horses down-regulated the proportion of IL-4-producing cells and IL-4 production in stimulated cultures of PBMC from 1st generation IBH. This inhibition was mimicked by a combination of IL-10 and TGF-beta1 but not by the single cytokines. Cultures of stimulated PBMC of healthy 2nd generation horses produced a low level of IL-4, but IL-4 production was increased by anti-equine IL-10 and anti-human TGF-beta1. This shows for the first time that in horses, IL-10 and TGF-beta1 combined regulate IL-4 production in vitro. It is suggested that in this naturally occurring IgE-mediated allergy, IL-10 and TGF-beta1 have a role in the down-regulation of IL-4-induced allergen-specific Th2 cells, thereby reducing the incidence of IBH.

Asthma in young south Asian women living in the United Kingdom: the importance of early life

BACKGROUND: Studies of immigrants suggest that the environment during fetal life and duration of residence in the host country might influence the development of asthma. Little is known about the importance of the timing of the exposure in the host country and whether migrants might be especially vulnerable in certain age windows. OBJECTIVE: We compared the reported prevalence of asthma between young white and south Asian women in the United Kingdom, and investigated associations with country of birth and age at immigration. METHODS: A questionnaire on atopic disorders was posted to 2380 south Asian and 5796 white young mothers randomly sampled in Leicestershire. Data on ethnicity were also available from maternity records. Data were analysed using multivariable logistic regression and a propensity score approach. Results The reported prevalence of asthma was 10.9% in south Asian and 21.8% in white women. South Asian women who migrated to the United Kingdom aged 5 years or older reported less asthma (6.5%) than those born in the United Kingdom or who migrated before age 5 (16.0%), with an adjusted odds ratio of 0.38 [95% Confidence Interval 0.23-0.64, P<0.001]. For those who migrated aged over 5 years, the prevalence did not alter with the duration of residence in the United Kingdom. Current exposure to common environmental risk factors had relatively little effect on prevalence estimates. CONCLUSION: These data from a large population-based study support the hypothesis that early life environmental factors influence the risk of adult asthma.

Snoring in preschool children: prevalence, severity and risk factors

Epidemiological data on snoring from preschool children are scarce, although habitual snoring (snoring on almost all nights) has been associated with poor long-term outcomes. In a population survey of 6,811 children aged 1-4 yrs (from Leicestershire, UK) the present authors determined prevalence, severity and risk factors for snoring, especially habitual snoring. In 59.7% of the children, parents reported snoring in the previous 12 months, including 7.9% with habitual snoring and 0.9% with habitual snoring and sleep disturbance. Prevalence of habitual snoring increased with age from 6.6% in 1-yr-olds to 13.0% in 4-yr-olds. Habitual snoring was associated with: one and both parents smoking (adjusted odds ratio (OR) 1.46 and 2.09, respectively); road traffic (OR 1.23); single parent (OR 1.60); and in White but not South Asian children, socioeconomic deprivation (OR 1.25 and 2.03 for middle and upper thirds of Townsend score, respectively). Respiratory tract symptoms related to atopic disorders and to respiratory infections were strongly associated with snoring; however, body mass index was not. In conclusion, habitual snoring is common in preschool children with one-third of cases attributable to avoidable risk factors. The strong association with atopic disorders, viral infections and environmental exposures suggests a complex aetiology, based on a general vulnerability of the respiratory tract.

Wheeze and asthma prevalence and related health-service use in white and south Asian pre-schoolchildren in the United Kingdom

BACKGROUND: Epidemiological data for south Asian children in the United Kingdom are contradictory, showing a lower prevalence of wheeze, but a higher rate of medical consultations and admissions for asthma compared with white children. These studies have not distinguished different asthma phenotypes or controlled for varying environmental exposures. OBJECTIVE: To compare the prevalence of wheeze and related health-service use in south Asian and white pre-schoolchildren in the United Kingdom, taking into account wheeze phenotype (viral and multiple wheeze) and environmental exposures. METHODS: A postal questionnaire was completed by parents of a population-based sample of 4366 white and 1714 south Asian children aged 1-4 years in Leicestershire, UK. Children were classified as having viral wheeze or multiple trigger wheeze. RESULTS: The prevalence of current wheeze was 35.6% in white and 25.5% in south Asian 1-year-olds (P<0.001), and 21.9% and 20.9%, respectively, in children aged 2-4 years. Odds ratios (ORs) (95% confidence interval) for multiple wheeze and for viral wheeze, comparing south Asian with white children, were 2.21 (1.19-4.09) and 1.43 (0.77-2.65) in 2-4-year-olds after controlling for socio-economic conditions, environmental exposures and family history. In 1-year-olds, the respective ORs for multiple and viral wheeze were 0.66 (0.47-0.92) and 0.81 (0.64-1.03). Reported GP consultation rates for wheeze and hospital admissions were greater in south Asian children aged 2-4 years, even after adjustment for severity, but the use of inhaled corticosteroids was lower. CONCLUSIONS: South Asian 2-4-year-olds are more likely than white children to have multiple wheeze (a condition with many features of chronic atopic asthma), after taking into account ethnic differences in exposure to some environmental agents. Undertreatment with inhaled corticosteroids might partly explain their greater use of health services.

Marked disturbance of calcium homeostasis in mice with targeted disruption of the Trpv6 calcium channel gene

We report the phenotype of mice with targeted disruption of the Trpv6 (Trpv6 KO) epithelial calcium channel. The mice exhibit disordered Ca(2+) homeostasis, including defective intestinal Ca(2+) absorption, increased urinary Ca(2+) excretion, decreased BMD, deficient weight gain, and reduced fertility. Although our Trpv6 KO affects the closely adjacent EphB6 gene, the phenotype reported here is not related to EphB6 dysfunction. INTRODUCTIOn: The mechanisms underlying intestinal Ca(2+) absorption are crucial for overall Ca(2+) homeostasis, because diet is the only source of all new Ca(2+) in the body. Trpv6 encodes a Ca(2+)-permeable cation channel responsible for vitamin D-dependent intestinal Ca(2+) absorption. Trpv6 is expressed in the intestine and also in the skin, placenta, kidney, and exocrine organs. MATERIALS AND METHODS: To determine the in vivo function of TRPV6, we generated mice with targeted disruption of the Trpv6 (Trpv6 KO) gene. RESULTS: Trpv6 KO mice are viable but exhibit disordered Ca(2+) homeostasis, including a 60% decrease in intestinal Ca(2+) absorption, deficient weight gain, decreased BMD, and reduced fertility. When kept on a regular (1% Ca(2+)) diet, Trpv6 KO mice have deficient intestinal Ca(2+) absorption, despite elevated levels of serum PTH (3.8-fold) and 1,25-dihydroxyvitamin D (2.4-fold). They also have decreased urinary osmolality and increased Ca(2+) excretion. Their serum Ca(2+) is normal, but when challenged with a low (0.25%) Ca(2+) diet, Trpv6 KO mice fail to further increase serum PTH and vitamin D, ultimately developing hypocalcemia. Trpv6 KO mice have normal urinary deoxypyridinoline excretion, although exhibiting a 9.3% reduction in femoral mineral density at 2 months of age, which is not restored by treatment for 1 month with a high (2%) Ca(2+) "rescue" diet. In addition to their deranged Ca(2+) homeostasis, the skin of Trpv6 KO mice has fewer and thinner layers of stratum corneum, decreased total Ca(2+) content, and loss of the normal Ca(2+) gradient. Twenty percent of all Trpv6 KO animals develop alopecia and dermatitis. CONCLUSIONS: Trpv6 KO mice exhibit an array of abnormalities in multiple tissues/organs. At least some of these are caused by tissue-specific mechanisms. In addition, the kidneys and bones of Trpv6 KO mice do not respond to their elevated levels of PTH and 1,25-dihydroxyvitamin D. These data indicate that the TRPV6 channel plays an important role in Ca(2+) homeostasis and in other tissues not directly involved in this process.

[Anti-interleukin-5 therapy for eosinophilic diseases]

In a number of diseases with eosinophilia, elevated interleukin (IL)-5 levels are detected in the peripheral blood and/or tissues. IL-5 plays an important role in regulating the production, differentiation, recruitment, activation, and survival of eosinophils. Therefore, neutralizing IL-5 by blocking antibodies seems a promising approach in the treatment of eosinophilic diseases. Clinical trials have demonstrated that anti-IL-5 therapy results in a rapid decrease in peripheral blood eosinophil numbers. Moreover, improvement of symptoms in patients with lymphocytic variants of hypereosinophilic syndromes, in eosinophilic esophagitis and chronic rhinitis with nasal polyposis has been observed. In contrast, in patients with bronchial asthma or atopic eczema, anti-IL-5 therapy showed only moderate or no clinical effects. Future studies will have to identify those eosinophilic diseases in which anti-IL-5 antibodies are effective, perhaps with the help of newly developed biomarkers.