Positive Radioallergosorbent Test Research Articles

Prevalence of food allergy and other atopy among children with eosinophilic esophagitis in single center retrospective study, Riyadh, Saudi Arabia

Background: Eosinophilic esophagitis (EoE) is increasingly recognized as a significant public health issue in pediatric populations. The multifaceted mechanisms involving genetic, environmental, and immunological factors, particularly the role of allergens, are central to understanding EoE's pathogenesis. This study aims to analyze the prevalence of food allergies and atopic diseases among children diagnosed with EoE, offering insights into their interrelations and informing improved management strategies. Methods: This retrospective study analyzed 47 pediatric patients diagnosed with EoE at the Allergy and Gastroenterology Clinic, Children's Hospital, King Saud Medical City, Riyadh, from February 2012 to December 2018. Patients were selected based on documented food allergies, anaphylactic reactions, comorbid atopic conditions, positive radioallergosorbent test (RAST) results, and elevated eosinophilia. Data collection involved medical records and detailed family questionnaires. Immunological assays and endoscopic biopsies were used for diagnosis, with EoE defined as more than 15 eosinophils/high power field. Results: The study population predominantly comprised Saudi males, with a mean age of 8.36 years. A significant portion had consanguineous parents. Notable findings include a high prevalence of asthma (46.8%), allergic rhinitis (23.4%), and eczema (25.5%). The most common food allergens identified were peanuts, nuts, and seafood. Asthma severity varied, with ventolin and fluticasone being the most prescribed medications. Laboratory investigations showed elevated white blood cell, absolute neutrophil count, lymph, eosinophil sedimentation rat (ESO), eosinophil percentage, and immunoglobulin E (IgE) levels. RAST indicated specific allergen sensitivities in 34.0% of patients. Conclusion: This study provides essential insights into the demographic, clinical, and therapeutic aspects of pediatric EoE, emphasizing the importance of a comprehensive, personalized approach to management.

Assessment of a Multispecies Probiotic Supplement for Relief of Seasonal Allergic Rhinitis: A Randomized Double-Blind Placebo-Controlled Trial

Background: Early phase clinical research provided initial support for the use of a multispecies probiotic supplement to improve quality of life (QoL) in adults with seasonal allergic rhinitis (AR) and reduce the use of AR symptom relieving medication. This study aimed to confirm these early phase findings in a double-blind randomized placebo-controlled trial. Methods: Individuals, aged 18-65 years, with a minimum 2-year history of AR, moderate-to-severe AR symptoms, and a positive radio-allergosorbent test to Bermuda (Couch) Grass were randomized to receive either a multispecies probiotic supplement (total colony-forming units 4 × 109/day) or placebo twice daily for 8 weeks. A mini-rhinoconjunctivitis quality of life questionnaire (mRQLQ) scale was administered at screening, days 0, 28, and 56. The proportion of participants with a >0.7 improvement in mRQLQ was the primary outcome. Participants also completed a daily symptom and medication diary during the supplementation period. Results: There were 165 participants randomized, with 142 included in the primary outcome analysis. The percentage of participants meeting the threshold for a clinically meaningful reduction in the mRQLQ from days 0 to 56 was not significantly different between groups (61% vs. 62%, p = 0.90). However, 76 participants had a clinically meaningful improvement in QoL (decrease in mRQLQ >0.7) prior to the start of supplementation (screening to day 0). Conclusion: Changes in self-reported QoL and other disease severity metrics between screening and the start of supplementation limited the ability to discern an effect of supplementation and highlight the need for adaptive clinical trial designs in allergy research. Clinical Trial Registration: The trial was registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12619001319167).

An epidemiological study of food allergy in a regional hospital in Ireland

Food allergy is rapidly becoming a significant burden on the paediatric population of developed countries.[1,2] Type 1 allergy causes much anxiety and leads to some of the very acute and distressing presentations to paediatric A&E. Misconception and fears regarding the use of adrenaline preparations is one of the causative factors, although there is a huge evidence base that shows the safety and effectiveness of these preparations in managing the true and suspected cases of type 1 allergy.[3] In the Paediatric unit in Our Lady of Lourdes Hospital, Drogheda there is an allergy clinic which runs as an out-patient service. Our aim was to establish a database of children who presented to these clinics and record the allergens (both food and aeroallergens) to which they had a positive reaction. We included those that had a positive skin prick test or radioallergosorbent test (RAST), or both. It is only by creating such a database that we can determine both the scale of the problem in our area and the adequacy of services provided. Using this information we could proceed further to audit our services and make any improvements in the future. The aim of the allergy register was to: • Obtain information about 1) the number of children presenting to our allergy clinic and 2) the prevalence of food allergy within this group and the type of allergens (nut, fish, milk, egg). • Determine the number of children with associated atopic conditions (asthma, eczema, hayfever). • Record the nature of reaction to the various allergens. • Record the patients who had been given adrenaline pens so that timely replacements can be provided in the future.

Penicillin allergy evaluation: experience from a drug allergy clinic in an Arabian Gulf Country, Kuwait.

BackgroundHypersensitivity to penicillin has been studied worldwide, but data regarding patterns of sensitization in Arabian Gulf countries are scarce.ObjectiveTo describe the patterns of penicillin hypersensitivity during a 6-year study in Kuwait in terms of demographics, type of the culprit drug, in vivo and in vitro allergy testing.MethodsOne hundred and twenty-four patients referred to the drug allergy clinic for penicillin allergy were fully evaluated by skin prick and intradermal testing. Drug provocation test was done on patients with negative results.ResultsA total of 124 patients were evaluated for penicillin allergy. Mean age was 37.8 (standard deviation, 12.7) years, range from 8 to 74 years. Thirty-nine male (31.5%) and 85 female patients (68.5%) were included. Diagnosis of penicillin allergy was confirmed in 46 patients (37.1%). Among the 44 confirmed allergic patients by skin evaluation we had 15 (34.1%) positive skin prick test, and 29 (65.9%) positive intradermal testing. Among patients with positive skin testing, 47.7% were positive to major determinant benzylpenicilloyl poly-L-lysine, 20.4% to minor determinant mixture, 50.0% to penicillin G and 40.9% to ampicillin; 13.6% of patients were positive to amoxicillin by skin prick test. One patient had a positive radioallergosorbent test and one had a positive challenge test.ConclusionPenicillin allergy is a common problem with an incidence of about one third in our study subjects.

Effect of vitamin D on T-helper type 9 polarized human memory cells in chronic persistent asthma

BackgroundVitamin D suppresses inflammation and vitamin D deficiency is linked to the severity of asthma symptoms. T-helper type 9 (TH9) cells are important in the pathogenesis, yet the effects of vitamin D on this subset of inflammatory T-helper cells from patients with chronic asthma is unknown. ObjectiveTo determine the effects of vitamin D and dexamethasone on TH9 memory cells from adults with chronic persistent asthma and on a recall response to dust mite allergen. MethodsT-helper memory cells were cultured with cytokines that drive TH9 polarization with vitamin D and/or dexamethasone. Peripheral blood mononuclear cells (PBMCs) from patients with radioallergosorbent test results for house dust mite were stimulated with allergen in the presence or absence of vitamin D. Intracellular cytokines, transcription factors, and identification of cell surface phenotypic markers were determined by flow cytometry. ResultsVitamin D decreased interleukin (IL)-9, IL-5, and IL-8 but increased IL-13+ cells in TH9 cultures. Transcription factors PU.1 and interferon regulatory factor 4 were downregulated by vitamin D but not GATA3 and c-MAF. When PBMCs from patients with positive radioallergosorbent test results were stimulated with dust mite allergen, vitamin D decreased IL-9, IL-5, and IL-13 in T-helper cells (CD4+). TH9 cells present in a recall response were classically TH2 (CD294+), and polarization by transforming growth factor-β and IL-4 altered that phenotype. ConclusionVitamin D decreased inflammatory cytokine profiles in TH9 memory cells and CD4+ cells stimulated with dust mite allergen. Vitamin D is additive with dexamethasone in decreasing inflammatory cytokine production from T-cell subsets implicated in asthma.

Prediction of new-onset asthma and nasal allergy by skin prick test and RAST in a cohort of adults

Limited information exists regarding the incidence and predictors of asthma and nasal allergy in adulthood. We determined the incidence rate of asthma and nasal allergy in adults and assessed the predictive value of skin prick tests (SPTs) and radioallergosorbent tests (RASTs) for these two outcomes. Two German centres involved in the European Community Respiratory Health Survey conducted a follow-up assessment in 2012 of the baseline participants (1185 adults aged 21-47 years assessed in 1990). The predictive value of SPTs and RASTs on new-onset asthma and nasal allergy was assessed by Cox regression and by calculating the positive or negative predictive value. During the 20 years between baseline and follow-up, 3.1 and 4.4 per 1000 person-years of new-onset asthma and nasal allergy cases were recorded, respectively. The hazard ratios for SPTs of any specific and of all aeroallergens combined were slightly higher than those of RASTs for asthma and nasal allergy. The negative predictive values of both the SPT and RAST were very high and similar (0.94-0.96), whereas the postive predictive values were low (0.09-0.20). Positive SPT results showed a better association with new onset asthma and nasal allergy than positive RAST either to any specific aeroallergens or to all combined.

Blood tests and histological correlates in children with eosinophilic oesophagitis

To determine the relationship between blood tests and oesophageal histology in Eosinophilic oesophagitis (EoE). All children diagnosed with EoE at one hospital from 2000 to 2009 were considered for inclusion in this study. Three blood test results were analysed, blood eosinophil count, serum total immunoglobulin E (IgE) and radioallergosorbent tests (RAST) to common food allergens. Oesophageal histology was prospectively re-reviewed, and mean eosinophil counts were enumerated. Blood test results were correlated with oesophageal eosinophil counts using Spearman's rank test. Forty children (70% boys) were included in this study, median age at diagnosis 6.5 years (range 0-15). At the time of diagnosis, 78% of children had a raised blood eosinophil count, 90% had a raised serum total IgE and 83% had one or more positive RAST tests. The mean oesophageal eosinophil count was significantly correlated with both blood eosinophil count (p=0.008) and serum total IgE level (p=0.008). This study shows that blood tests are often abnormal in children with EoE at the time of diagnosis. Our data demonstrate an association between histological abnormalities and blood test results in children with EoE.

Amoxicillin And Tlr Agonists Increase The Maturation Of Dendritic Cells From Patients With Non-immediate Allergy To Betalactams

M O N D A Y 755 Different Patterns Of IgE Recognition To Amoxicillin In Patients With Immediate Hypersensitivity Reactions A. Ariza, C. Mayorga, I. Do~na, F. Gomez, E. Perez-Inestrosa, M. I. Monta~nez, J. L. Rodriguez-Bada, M. A. Guerrero, M. Blanca, M. J. Torres; Research Laboratory F-IMABIS, M alaga, SPAIN, Allergy Service, Carlos Haya Hospital, M alaga, SPAIN, Organic Chemistry Department, Chemistry University, M alaga, SPAIN. RATIONALE: The optimal recognition of penicillin determinants, including amoxicillin, by specific IgE antibodies requires a covalent binding to a carrier molecule. The nature of the carrier and its contribution to the antigenic determinant is not well known. The aim of this study was to evaluate the recognition of different amoxicillin structures by specific IgE antibodies in patients with immediate hypersensitivity reactions. METHODS: Patients (N521) with immediate hypersensitivity reactions to amoxicillin and positive radioallergosorbent test (RAST) were included. RASTwas done using benzylpenicillin and amoxicillin bound to poly-Llysine (BPO-PLL and AXO-PLL). RAST inhibition assays used AXOPLL in the solid phase and amoxicillin, amoxicilloic acid, amoxicillin bound to butilamine (AXO-BA), human serum albumin (AXO-HSA) and dendrimers (AXO-DN) in the fluid phase. RESULTS:We observed two clear defined patterns of IgE recognition: A) Cases (N58) with a higher recognition to free amoxicillin being lower to amoxicilloic acid, AXO-BA, AXO-HSA and AXO-DN; B) Cases (N513) which recognize both free and conjugated amoxicillin in similar degree with low recognition to amoxicilloic acid. Group A corresponds to patients with RAST only positive to AXO-PLL and Group B to those positive to BPO-PLL and AXO-PLL. CONCLUSIONS: These results seems to indicate that IgE recognition is influenced by the binding and nature of the carrier molecule (Group A), with others mainly recognizing the amoxicillin structure independently of the nature of the carrier (Group B). The fact that amoxicilloic acid is not optimally recognized in Group B reinforced the need of conjugation to a carrier in this group of patients.

Long-term follow-up of children after submucosal diathermy to the inferior turbinate for rhinitis

Background There is currently poor evidence base to support turbinate surgery in children. Submucosal diathermy (SMD) is a day case procedure offered to children who have refractory rhinitis. There is currently no well-defined population who will benefit from this procedure. The Glasgow Children's Benefit Inventory (GCBI) is a validated questionnaire that can be used to assess benefit following an intervention. Methods In September 2009, questionnaires were sent by post to the parents of 70 children who underwent SMD between 2003 and 2006. If no response was received, an attempt to contact the parents by telephone was made. These questionnaires were then analysed to ascertain benefit scores. Results Returned questionnaires were received for 47 children (68%). 70% (33) felt that this had been a worthwhile procedure. Residual nasal symptoms were recorded, of which rhinorrhea was the most frequent (30, 64%), followed by nasal blockage (28, 60%). Of these children, 23 had a positive radio-allergosorbent test (RAST) and 21 were negative. Overall the median GCBI for children receiving SMD was 19.5. This was elevated in the RAST positive group (median score 27) and lower for the RAST negative group (median score 14). Conclusion This study highlights some benefit to inferior turbinate study in children by using the GCBI. Improved benefit was not demonstrated significantly in older or younger children or in RAST positive or negative children. Further studies, by means of a randomised controlled trial are required to provide a better level of evidence for this procedure.

Study of Allergic Rhinitis in Childhood

Allergic rhinitis is common among children and quite often represents a stage of the atopic march. Although sensitization to food and airborne allergens may appear in infancy and early childhood, symptoms of the disease are usually present after age 3. The aim of this study was to determine the most frequent food and indoor and outdoor respiratory allergens involved in allergic rhinitis in children in the region of Piraeus. The study was performed in the outpatient clinic of otolaryngologic allergy of a general hospital. Fifty children (ranged 6–14 ) with symptoms of allergic rhinitis and positive radioallergosorbent test (RAST) for IgE antibodies or skin prick tests were included in the study. Thirty six (72%) of the subjects of the study had intermittent allergic rhinitis. The most common aeroallergens determined were grass pollens and Parietaria, whereas egg and milk were the food allergens identified. The detection of indoor and outdoor allergens in the region of Piraeus, based on skin prick tests and RAST tests, showed high incidence of grasses and food allergens, which is similar to other Mediterranean countries.

Ethylene Oxide Allergy in Patients on Hemodialysis Waiting for Kidney Transplantation: Logistical Nightmare or Challenge? A Case Report

Ethylene oxide (EO) is widely used as a sterilization gas for heat-sensitive devices. In EO-sensitized patients, this type of sterilization can cause rare but major allergic reactions such as hives, rash, asthma, or anaphylactic shock. Hemodialysis patients in particular are at risk of developing hypersensitivity to EO. In these patients, surgical interventions should be planned far in advance allowing a thorough EO-free preparation of all equipment needed for the surgery as well as for the pre-, peri-, and postoperative care. In contrast to elective surgery, kidney transplantation with allografts from deceased donors cannot be planned; exact timing is unpredictable. Furthermore, transplantation may take place years after patients have been put on the waiting list. Listing of patients sensitive for EO is therefore a logistical and medical challenge for all health care professionals involved in the patient's care (eg, surgeons, nephrologists, anesthestetists, nurses, pharmacists, and sterilization specialists). This case report describes a patient with chronic kidney disease stage V who developed EO allergy during hemodialysis while waiting for a kidney transplantation. Diagnosis was made based on clinical signs and confirmed biochemically (including a positive radioallergosorbent test). Because the only treatment is avoidance of contact with EO-sterilized materials, a strict EO-free protocol was developed to allow an uneventful transplantation thereafter. Subsequently, 4 newly diagnosed EO-sensitive patients on the active kidney transplantation waiting list were diagnosed, and 1 of these patients has been transplanted successfully. EO allergy in patients on the waiting list for kidney transplantation is a unique challenging situation which, to the best of our knowledge, has not been reported yet for kidney transplantation. This report further highlights the logistical preparation of a renal transplantation, including anesthesiologic, surgical, and postoperative care.

Elimination and provocation test in cow's milk hypersensitive children

Background Allergic disease in infancy mostly related to cow's milk allergy. The prevalence of cow's milk hypersenstivity in chil- dren has increased steadily in the past years; therefore diagnostic accuracy is important and every symptomatic child with positive specific lgE should be followed by elimination and provocation. Objective To diagnose cow's milk hypersensitivity on children un- der three years old using elimination and provocation methods. Methods This was a clinical diagnosis study, in which children with allergy symptoms were examined for cow's milk sensitivity using prick test or lgE Radioallergosorbent test (RAST). Those with positive results underwent an elimination for minimal of 2 weeks and were challenged aterwards. The study was a qualitative diagnostic test with the gold standard of recurrence of symptoms after challenge test. Results There were forty subjects included in the challenge pro- cess with mean age of 17 months old. Boys and girls were equally distributed. There were 6 7% subjects with positive results on challenge with positive prick test and 64% positive challenge with history of positive lgE RAST. Sixty-five percents of subjects with positive results on challenge had more than 2 weeks elimination period. There was no statistical significance found in children with positive results on challenge, using neither prick test or lgE RAST. Conclusions Cow's milk protein allergy can be diagnosed on chil- dren less than 3 years old by applying elimination and challenge procedure. lgE sensitivity alone can not determine hypersensitivity

Importance of animal epithelia as house dust allergens

Among sera from 379 patients with atopy tested with the radio-allergo-sorbent test (RAST) for domestic dust and house-dust mite (Dermatophagoides pteronyssinus), 104 were positive only for house dust. Positive results for both house dust and house-dust mites were obtained in 130, while in 145 the RAST result was positive only for house-dust mites. 104 sera, negative for house-dust mites, were tested by RAST for specific IgE against epithelia from cats, dogs, guinea-pigs, horses and cattle, as well as cockroaches (Blatella germanica). A positive RAST result for at least one of these animal epithelia was obtained in 89.5% of sera, for cockroaches in 7.7%. Cat epithelia were of special importance with respect to both rate and degree of sensitization. Except for dog epithelia, sensitization (as demonstrated with RAST) against the other domestic animal epithelia was more frequent than the history had indicated. After immune-adsorption of its homologous specific IgE with cat epithelia, but not after adsorption with epithelia of dog, guinea-pig, horse and cattle, inhibition of the house-dust RAST level in 60-80% was demonstrated in pool-sera. This finding proves that sensitization to cat epithelia, in addition to house-dust mites, can be the cause of a positive house-dust RAST reaction; cat epithelia are an important allergen of inhalation allergies caused by house dust.

Pectin anaphylaxis and possible association with cashew allergy

Inhalation of pectin has been identified as a cause of occupational asthma. However, allergic reactions to orally ingested pectin have not been reported. To describe a child with pectin-induced food anaphylaxis and to discuss its possible relationship to cashew allergy. A 3 1/2-year-old boy developed anaphylaxis once after eating cashews and later after eating a pectin-containing fruit "smoothie." He also has a history of generalized pruritus after eating grapefruit. Skin tests or radioallergosorbent tests (RASTs) were performed to pectin and other suspected food allergens. The child had a positive skin prick test reaction to pectin and a high RAST reaction to cashew and pistachio. He had a low-level positive RAST reaction to grapefruit. Results of allergy tests for the other potential food allergens were negative. The pectin in the smoothie was confirmed to be of citrus origin. Review of previous case reports of pectin-induced occupational asthma revealed several patients with allergies to and cross-reactivity with cashew. Ingestion, not only inhalation, of pectin can cause hypersensitivity reactions. Cashew, and possibly pistachio, allergy may be associated with pectin allergy, and the possibility of pectin allergy should be considered in cashew- or pistachio-allergic patients who have unexplained allergic reactions.

Late diagnosis of tree nut and sesame allergy in patients previously sensitized but tolerant to peanut

Recent studies have indicated that tolerance to peanut can occur in patients with a history of peanut allergy. Tree nut and sesame allergies have been reported to occur at increased incidence in patients with peanut allergy. Although the coexistence may be simply due to a predisposition to food allergy in these individuals, cross-reactivity has been demonstrated between peanut and tree nuts and between peanut and sesame seed. To describe 3 patients previously sensitized but tolerant to peanut who were subsequently diagnosed as having either tree nut or sesame allergy. All the patients had a clinical history of peanut sensitivity and underwent follow-up peanut skin testing to commercial extracts using a bifurcated needle followed by a graded peanut challenge. One patient had a previous positive radioallergosorbent test reaction to sesame and underwent a graded sesame challenge. All the patients had negative peanut challenge results. Two patients subsequently had exposure to tree nuts at home and had systemic reactions and positive skin test reactions to the incriminated tree nut. One patient had a positive challenge reaction to sesame. Demonstration of tolerance to peanut may falsely reassure patients and physicians that patients no longer need to avoid tree nuts or sesame. Tree nut and sesame allergies can exist or develop in patients despite the development of tolerance to peanut.

IgE-mediated sensitization in seafood processing workers

Occupational-related allergic sensitization has been reported in fishery workers. The aim of this study was to investigate the prevalence, work-related symptoms, and possible risk factors in this occupationally exposed population in Greece. Sixty-four fish and seafood processing workers were compared with 60 controls regarding sensitization to seafood allergens. All participants underwent skin-prick tests (SPTs) with cod, sardines, shrimp, spiny lobster, crabs, salmon, mussels, and trout plus negative and positive control. The level of specific IgE (radioallergosorbent test) was evaluated in subjects with positive SPTs. Sensitization criteria were both SPTs and the corresponding positive radioallergosorbent test. Atopic status was tested with SPTs to seven common inhalant allergens. Potential risk factors for IgE sensitization were investigated using logistic regression analysis. Twenty-three of 64 workers (35.9%) were sensitive to at least one of the seafood allergens tested, and the prevalence in the control group was 10% (6/60; odds ratio, 5.049; 95% CI, 1.884-13.533). The prevalence of sensitization in allergen species tested in the fishery workers group was shrimp, 12.5%; spiny lobster, 10.9%; mussels, 7.8%; crabs 3.1%; cod, 3.1%; sardines, 1.6%; salmon, 1.6%; and trout, 1.6%. Presence of atopy (p = 0.02), intensity (p = 0.03), and duration of exposure (p = 0.03) was found as potential risk factors for IgE sensitization. Four of 64 (6.25%) workers reported work-related symptoms. Occupational exposure to fish and seafood significantly increases the likelihood of sensitization in seafood allergens and atopy, duration, and intensity of exposure may represent potential risk factors in seafood processing workers.

Brassica oleracea pollen, a new source of occupational allergens

Vegetable pollen is a rare source of occupational allergens. Occupational allergy has only been described in the case of paprika pollen and tomato pollen. We describe a new source of occupational pollen allergy. To study the incidence and the impact of broccoli and cauliflower pollen allergy in employees involved in classical plant breeding. Fifty-four employees of five companies working with cauliflower (Brassica oleracea botrytis) and broccoli (B. oleracea italica/cymosa) pollen were eligible for complete evaluation. Allergy to cauliflower and broccoli pollen was evaluated by questionnaire and determination of sensitization by radioallergosorbent test (RAST) and skin-prick tests (SPT). SPT and RAST were performed with a panel of commercial and homemade extracts from cauliflower and broccoli pollen. Work-related symptoms such as rhinitis, conjunctivitis, asthma and urticaria caused by B. oleracea pollen were reported by 44% of the participants (24/54), of whom all but one had positive SPT for cauliflower- and/or broccoli-pollen/flower extracts and 58% (14/24) had positive RAST results. Symptoms had developed within the first 2 years in 33% of the patients. Six patients had to stop or change work. Brassica oleracea pollen is a new source of occupational allergen with strong allergenic potential leading to symptoms in almost half of the exposed employees.

Aerobiological studies and low allerginicity of Date-Palm pollen in the UAE

Date-Palm trees (Phoenix dactylifera L.) are the most abundant crop in the United Arab Emirates (UAE). The aim of this work was to conduct aerobiological studies on Date-Palm pollens and correlate that to allergenicity. An aerobiological survey was performed at three Date-Palm farms. Radioallergosorbent test (RAST) and total IgE were performed on 477 airborne allergic patients. Small mass bioactive constituents were fractionated and isolated by HPLC. Aerobiological studies demonstrate the short distance traveled by the Date-Palm pollens. Pollen counts were about 800 counts/m3 within the Date-Palm farms and decreased by about 80% just 100 meters away from the farm area and almost diminished beyond 200 meters. Scanning electron micrograph of the pollen grain showed a uniform smooth texture with an oval shape. Out of 477 airborne allergic patients having high total IgE counts, only 2.3% gave positive RAST for Date-Palm pollen. HPLC chromatogram separated the non-protein content of Date-Palm pollen into four distinct peak fractions. The present study revealed that Date-Palm pollens have a low allergic effect on airborne allergic people. The short distance traveled by the pollen, the smooth texture, the short pollination period and low molecular weight biomolecule content may be the main factors behind the low allergenicity.

IgE antibodies to ω‐5 gliadin in children with wheat‐induced anaphylaxis

Wheat can cause severe immunoglobulin E (IgE)-mediated systemic reactions including anaphylaxis but knowledge on relevant wheat allergens at the molecular level is scanty. Seven children (aged from 6 months to 13 years) experiencing from 2 to 10 anaphylactic reactions in a year after eating food-containing wheat were examined. Purified omega-5 gliadin was used as an allergen in IgE enzyme-linked immunosorbent assay (ELISA) and in skin prick testing (SPT). Wheat CAP radioallergosorbent test (RAST) and SPT were also examined. All seven anaphylactic children, but none of 15 control subjects had IgE antibodies to omega-5 gliadin in ELISA. Five of the six tested anaphylactic children showed positive SPT to omega-5 and crude gliadin, and all seven had positive wheat CAP RAST and SPT. One child was challenged with wheat, which caused anaphylaxis. After adherence to a wheat-free diet four children remained symptomless and three experienced one to two anaphylactic reactions. The present results show that wheat omega-5 gliadin is a major sensitizing allergen in children with wheat-induced anaphylaxis. They also suggest that omega-5 gliadin IgE ELISA could be used as a diagnostic test for this severe allergy.

Coughing in pre-school children in general practice: when are RAST's for inhalation allergy indicated?

To identify patterns of clinical history associated with extreme (high or low) probabilities of allergic sensitization in coughing children so as to restrict allergy testing to those with an intermediate probability of sensitization. A total of 752 children, aged 1-4, visiting their GPs for coughing (>or=5 days), were tested for IgE-antibodies to house dust mite, cat and dog [RadioAllergoSorbent Test (RAST)]. Parents completed a questionnaire on family history of atopy, breastfeeding, smoking, pets, and floor covering. Data of 640 children could be analyzed, 83 (13%) were IgE-positive. In a logistic regression analysis, a scoring formula for the prediction of being IgE-positive was constructed using variables from the patient's history. Significant contributors for sensitization were: age (3-4 yr), infantile eczema, positive family history of mite-allergy, sibling(s) with pollen-allergy, and smoking by parents. If only one of these characteristics is present, the probability of sensitization is < 25%. In such cases watchful waiting may be preferred over allergy testing. In other cases, a negative RAST may help to exclude sensitization, whereas a positive RAST helps to establish the diagnosis. Thus, acting on clinical history alone may save approximately 80% of RAST's. Patient history-derived information contributes to distinguishing children who are at low risk for sensitization to house dust mite, cat, and dog. The scoring formula may help GPs to identify children with a low probability of being sensitized. This may form the basis for watchful waiting. In others, allergy testing may be useful to gain more diagnostic certainty.