Positive Radioallergosorbent Test Research Articles

Immunoblot and radioallergosorbent test inhibition studies of allergenic cross-reactivity of the predatory mite Amblyseius cucumeris with the house dust mite Dermatophagoides pteronyssinus

In 1999, an extensive study among bell pepper growers showed that a predatory mite, Amblyseius cucumeris, is a potentially relevant source of occupational allergens because 23% of the population had positive skin prick test reactions. To investigate whether cross-reactivity between A. cucumeris and Dermatophagoides pteronyssinus is responsible for the cosensitization to both mite species found in 58.7% of A. cucumeris-sensitized greenhouse workers. Fifteen serum samples from greenhouse workers with work-related inhalant allergy and a positive radioallergosorbent test (RAST) reaction to A. cucumeris or D. pteronyssinus were selected for immunoblot analysis using extracts of both mites. A subselection (n = 5) was used for RAST and immunoblot inhibition to investigate potential cross-reactivity. On immunoblot, 2 distinct patterns were observed: one pattern showed common protein bands in A. cucumeris and D. pteronyssinus blots suggestive of cross-reactivity between A. cucumeris and D. pteronyssinus and the other pattern showed no shared protein bands. Dermatophagoides pteronyssinus RAST inhibition with A. cucumeris extract was low in 4 serum samples (<25% inhibition) and nearly absent in 1 serum sample; A. cucumeris RAST inhibition with D. pteronyssinus extract was high in 1 serum sample (75% inhibition), low in 2 serum samples (35% and <15% inhibition), and absent in 2 serum samples. These results were confirmed by immunoblot inhibition experiments. Amblyseius cucumeris, a new occupational allergen, has species-specific antigens and common antigens that are cross-reactive with the house dust mite D. pteronyssinus.

Allergic rhinitis in children: association with asthma

SummaryThe incidence of allergic rhinitis in paediatric bronchial asthma patients was about 80% according to a questionnaire survey. Watery nasal discharge and nose rubbing were common symptoms of paediatric allergic rhinitis, while nasal congestion and sneezing increased with age. Although there were slight differences depending on the age of patients, one‐third to nearly half were believed to have nasal symptoms and asthma attacks. The first wheezing episode preceded nasal symptoms in the majority of patients, but onset of allergic rhinitis occurred &gt; 1 year before asthma in a little over 10%. The age of onset of allergic rhinitis was 1 year in these patients, which was clearly earlier than that observed in patients who first developed asthma (4 years). Furthermore, the incidence of cedar pollinosis was higher in patients who developed allergic rhinitis first than in those who developed asthma first, suggesting that asthma patients who develop allergic rhinitis first exhibit pronounced nasal hypersensitivity. Allergic inflammatory cells are present in the nasal mucosa of asthma patients who do not exhibit distinct allergic rhinitis symptoms, so nasal sensitization does not necessarily lead to allergic rhinitis symptoms, suggesting the existence of some other factor that induces nasal hypersensitivity. On nasal smear, the appearance of mast cells preceded a positive radioallergosorbent test (RAST), and the appearance of eosinophils and basophils was consistent with the degree of sensitization. Anti‐allergic agents appear efficacious in patients' mast cells positive on nasal smear cytology with negative house dust mite RAST, suggesting that nasal smear cytology may be useful when beginning medication.

Soybean oil is not allergenic to soybean-allergic individuals

Rationale Soybean-allergic individuals may be instructed by clinicians to avoid all foods derived from soybeans including soybean oil. However, highly refined soybean oil contains extremely low levels of protein. Previous work suggested that soybean oil was not allergenic, but the number of subjects challenged was small and the protein content of the oil was unknown. These deficiencies are rectified in this study. The study objective was to determine the allergenicity of highly refined soybean oil in soybean- allergic individuals. Methods Soybean-allergic subjects were selected by convincing history, positive skin test and positive radioallergosorbent test (RAST). Challenge materials consisted of a mixture of 4 soybean oils with the highest protein level from a group of 30 highly refined oils obtained from 30 different worldwide processors. Subjects consumed increasing doses of 1, 5, and 10 grams soybean oil (test material) and canola oil (control material) in a double-blind placebo controlled food challenge. Prepared oatmeal was the challenge vehicle. Results Twenty-eight soybean allergic subjects were challenged. No untoward reactions were encountered to either soybean or canola oils. No reaction with this number of subjects indicates with 95% certainty that 89.85% of soybean allergic individuals would not react to this soybean oil. Conclusions The lack of reactions to commercially available soybean oil supports the previous claim that hot solvent-extracted, bleached and deodorized soybean oil is not allergenic for soy-allergic individuals and avoidance of soybean oil of the type used in this study is unwarranted. The allergenicity of cold-pressed or expeller-pressed soybean oil remains uncertain.

Die Bedeutung von Brennesselpollen im Vergleich zu Beifußpollen für die saisonale allergische Rhinitis im Spätsommer

Introduction: The success rate of hyposensitization with mugwort pollen allergen in patients with late-onset seasonal allergic rhinitis is about 70%. Based on measurements over the last 3 years in the Dresden area using the Burkard pollen trap, it was found that during the main blossom season of mugwort, the nettle pollen pollution is high as well. With regard to the total amount of measured pollen, nettle pollen amounted to 78% compared to only 7% mugwort pollen. The aim of this study was to demonstrate the clinical relevance of the high nettle pollen exposure for patients with late-onset seasonal allergic rhinitis in the Dresden area. Methods: Thirty-six patients (17 female, 19 male, mean age 29.4 years) with a seasonal late summer allergic rhinitis were examined. All patients were sensitized to mugwort pollen. Radioallergosorbent test (RAST) and skin prick testing (SPT) for nettle pollen were performed on all patients. A nasal provocation test (NPT) with nettle pollen was performed in 17 patients sensitized to nettle pollen. Results of the provocation were investigated through rhinomanometry after 10, 20 and 30 minutes, respectively. Results: Twenty-four of the 36 patients exhibited a positive SPT and RAST for nettle pollen, showing the sensitization to nettle pollen. Of the 17 patients mentioned above, 8 patients had a positive NPT to nettle pollen. Conclusion: Results of this study indicated that a sensitization for mugwort pollen often coincides with sensitization for nettle pollen. The high nettle pollen exposure in the Dresden area is of clinical importance in the diagnosis of patients with late-onset seasonal allergic rhinitis. Therefore, we recommend that testing for nettle pollen (RAST, SPT and NPT) in patients with late summer allergies shall be included into standard diagnostic procedures. Patients with a positive NPT for nettle pollen may also qualify for hyposensitization therapy for nettle pollen.

The Role of Cow Milk Allergy in Increasing the Severity of Atopic Dermatitis

Previous studies have shown that up to 33% of children with atopic dermatitis have experienced food hypersensitivity and among different kinds of food allergens Cow Milk (CM) has almost always been one of the most common food allergens in children. The aim of this study is to evaluate the cow milk allergy (CMA) as an increasing factor of severity of atopic dermatitis. One hundred and nineteen children (between 1.5 months and 12 years of age) with atopic dermatitis in the sense of Hanifin and Rajka's criteria entered this study and the severity of atopic dermatitis was identified via the SCORAD index. In order to make the diagnosis of cow milk allergy, a careful history, and a familial history of allergy was taken and the results of skin prick test (SPT) with CM and 4 other food allergen extracts, Radioallergosorbent test (RAST) with CM allergens and a food challenge test with cow milk (fresh or dried) were used. Also a total serum IgE determination and an eosinophil count (with a stool exam) were accomplished. The clinical manifestations of atopic dermatitis in patients was started from their first day of life up to 10 years of age. The family history in 83% of the patients was positive. Positive skin prick test and RAST with CM allergens were positive in 37.9% and 29.3% of cases respectively and the response to challenge test with cow milk was positive in 35 out of 40 patients and in total 44.5% had CMA according to a positive history of cow milk allergy and a positive outcome of the IgE tests (SPT and/or RAST) or a positive challenge test with CM allergens. The results showed that the most common food allergens in patients with atopic dermatitis are certainly cow milk allergens (44.5%) whereas other food allergens are tomato (29.41%), egg (28.57%), nuts (9.24%) and wheat (3.36%) according to the skin prick test. The mean total serum IgE was 307.11 ± 6.56 IU/ml (range = 6–5000) in children with CMA and 81.04 ± 5.97 IU/ml (range = 1–5000) in children without CMA while the mean eosinophil count was 569.52 ± 3.02 count/ml (range = 67–8500) and 314.22 ± 2.94 count/ml (range = 5–5000) respectively. The mean severity of atopic dermatitis according to the SCORAD index was 60.76 in children with CMA and 44.29 in children without CMA. The severity of atopic dermatitis in patients with CMA was significantly higher than patients without CMA (p < 0.0001). Also the mean total serum IgE and mean eosionophil counts in children with CMA were significantly higher than in children without CMA (P < 0.01 and p < 0.0001, respectively). It shows the important role of CM allergen proteins in the induction and in increasing the severity of AD in children.

Specific immunoglobulin E in patients with immediate persulfate hypersensitivity.

Persulfate salts may cause contact urticaria, allergic and irritant contact dermatitis, rhinitis and asthma. The mechanism of the immediate reactions has been unclear. Positive prick test, skin application and nasal and bronchial provocations identify immediate allergy. There is only 1 previous report of specific binding of immunoglobulin E (IgE) to ammonium persulfate demonstrated by radioallergosorbent test (RAST). In the present study, fresh 2% ammonium and potassium persulfate solutions were used for prick testing. Patients with positive prick tests were further evaluated with open skin application, immunospot and RAST. Prick testing with persulfate salts was performed in a total of 138 patients. 7 patients had a positive reaction to at least 1 persulfate salt. 6 of the patients had had skin symptoms, urticaria, eczema or angioedema, because of contact with hair bleaches. Open application on healthy skin was performed in 4 patients, and 3 out of them had urticarial reactions. The sera of 5 patients were investigated with immunospot and RAST. On immunospot, specific binding of IgE to human serum albumin (HSA)-conjugated ammonium and potassium persulfate was found in 2 patients. 1 immunospot-positive patient also had a positive RAST to ammonium persulfate-HSA conjugate. The mechanism of immediate hypersensitivity to persulfates thus seems to be IgE-mediated at least in some patients.

Prevalence of Noninvasive Fungal Sinusitis in South Australia

The aim of this study was to document the prevalence of noninvasive fungal sinusitis in patients with chronic sinusitis and thick viscous secretions in South Australia. We studied of 349 patients with chronic rhinosinusitis undergoing endoscopic sinus surgery in a specialized rhinology practice. Patients with nasal polyposis and thick fungal-like sinus mucin had operative samples sent for microscopy and fungal culture. Evidence of atopy was taken as positive radioallergosorbent or skin-prick tests to fungi. One hundred and thirty-four (38%) patients were noted to have thick, viscid sinus mucin, raising suspicion of fungal disease. Ninety-three patients had positive fungal cultures or microscopy (26.6%). It was possible to classify 95.5% of the patients into subgroups of noninvasive fungal sinusitis or nonfungal sinusitis: 8.6% of patients with allergic fungal sinusitis, 1.7% of patients with allergic fungal sinusitis-like sinusitis, 15.2% of patients with chronic fungal sinusitis, one patient with a fungal ball, and the remaining 69% of patients with nonfungal chronic sinusitis. This is the first prospective study to evaluate the prevalence of these increasingly widely recognized conditions. It highlights the need for otolaryngologists to be alert to these not uncommon diagnoses in order for early, appropriate medical and surgical management to be instituted.

Immediate Allergic Reactions to Cephalosporins: Cross-Reactivity and Selective Responses

Purpose of the Study. Beta lactams are the most common agents involved in allergic reactions to antibiotics. There appears to be less cross-reactivity between penicillin and the newer generation cephalosporins. These latter agents might be associated with specific immunologic responses that do not cross-react with penicillins or other cephalosporins. These investigators examined the scope of immunoglobulin E (IgE) responses to various cephalosporins and penicillins in children and adults with histories compatible with cephalosporin allergy.Study Population. Six children and 24 adults who had experienced urticaria/angioedema or anaphylaxis after exposure to injectable cephalosporins were selected for study. Reactions had occurred 1 to 48 months before evaluation. All 6 children had reacted to ceftriaxone, and 5/6 had suffered anaphylaxis.Methods. All participants were skin tested with penicilloylpolylysine, minor determinant mixture, penicillin G, ampicillin, and amoxicillin; also, cephalothin, cefuroxime, ceftazidime, cefotaxime, and ceftriaxone. The various cephalosporins were tested at 2 mg/mL, a concentration previously shown to be a nonirritant in healthy control subjects. Radioallergosorbent tests (RASTs) were also performed to benzylpenicilloyl-polylysine, amoxicilloyl-polylysine, ampicilloyl-polylysine, and to the various cephalosporins conjugated to polylysine.Results. All 6 children had positive skin tests (1 prick, 5 intradermal) for the culprit drug, but none had positive RASTs. No child reacted to any of the other cephalosporins or to any penicillin reagents. Among the adults, all but 2 individuals had positive skin tests, and 9 had positive RASTs to the culprit drugs. No one had positive RASTs with negative skin tests. Two adults had a total of 3 completely negative test batteries, including agents that had caused anaphylaxis 24, 40, and 45 months earlier. A total of 10 adults reacted to >1 cephalosporin, and there was no compelling pattern of cross-reactivity. Similarly, there was no pattern apparent in the 4 patients who reacted to penicillin reagents.Conclusions. Most patients with histories of allergic reactions to cephalosporins are sensitized to determinants specific for the given drug, although some display cross-reactivity to other cephalosporins. A few individuals display reactivity to penicillin determinants, but this is not predicted by culprit drug or nature of reaction.Reviewer’s Comments. This study focused on reactions after parenterally administered cephalosporins and clearly highlights the low but unpredictable incidence of cross-reactivity among these agents and the penicillins. Pediatricians dealing with the quandary of a child with a history of suspected reaction from an orally administered preparation in the outpatient setting should realize that other cephalosporins might be tolerated just fine. Because there are no reagents for in vivo or in vitro testing for these oral cephalosporins, the only test is administration followed by a couple hours of observation in the office. For the hospitalized child with a history of allergy to an injected cephalosporin and in need of such now, it makes sense to skin test first with the agent(s) to be considered. If the history is one of reacting to an orally administered cephalosporin, it is probably even likelier that the parenteral agent would be well-tolerated. However, because most severe reactions follow injected drug at any age, it would be wise to skin test with the desired injectable cephalosporin first. Finally, the authors described 2 adults with histories of anaphylaxis but with currently negative tests, as mentioned above. These cases represented some of the longest intervals from time of reaction to evaluation date among all the patients studied. Drug allergy often wanes over months and years, and this can happen even when the initial reactions were life-threatening.

The prevalence of latex allergy in operating theatre staff.

Latex allergy has become increasingly common amongst health care workers. The prevalence of latex allergy in 102 theatre personnel at Princess Alexandra Hospital was determined by the results of a standardized questionnaire and a latex specific IgE radioallergosorbent test (RAST). Volunteers had their forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) measured at the beginning and end of their working shifts. Only one of 102 volunteers had a positive latex specific IgE RAST and he also experienced both local and systemic symptoms with latex exposure and a deterioration in daily FEV1/FVC. The 14 volunteers using asthma medications had significantly higher incidence of operating theatre symptoms (10/14), local reactions (8/14), and atopy (14/14). There was no clinically significant daily change in FEV1 in the total population or any specific group. The 1% (1/102) prevalence of latex allergy and sensitization in theatre staff demonstrates a much lower incidence than previously reported (12.5%, 15.8%).

Polyisotypic antipeanut‐specific humoral responses in peanut‐allergic individuals

Peanut-containing food products may induce severe clinical reactions in sensitized subjects, and high levels of antipeanut IgE have been reported in the literature. Immunotherapy, proposed for the prevention of severe accidents, is often ill-tolerated and only partly efficient. This could be due to the spontaneous development of polyisotypic antipeanut antibodies. To appreciate the presence and reactivity of other isotypes other than IgE of peanut-specific antibodies in serum samples from peanut-sensitized subjects. Serum samples were obtained from 20 non-sensitized subjects and 23 sensitized patients divided in three groups according to their response to peanut oral challenge (no response or response to high or low doses, respectively). Peanut-specific IgG, IgG subclasses, IgA and IgM were assayed using an ELISA, and their reactivity against peanut proteins tested using Western Blot. A large dispersion of antipeanut antibody levels was observed in the three groups of patients, high levels of IgG, IgG1, IgG4 and IgA usually correlating with highly positive radioallergosorbent test (RAST). Such high levels were observed at onset in four patients who underwent peanut immunotherapy who had side effects and poor efficiency. Western blotting demonstrated that the polyisotypic response observed was directed to several peanut antigens, including the major allergens, Ara h1 and Ara h2. Peanut-sensitized patients who spontaneously develop specific IgE, display polyisotypic-specific antibody responses, whatever their response to oral challenge. This might explain the poor efficiency of peanut rush immunotherapy attempts.

Latex Allergy in Children on Home Mechanical Ventilation

Determining the incidence of latex allergy in children receiving home mechanical ventilation. The prevalence of latex allergy in the general population ranges from 0.1 to 1.0%. However, in patients with spina bifida and other chronic medical conditions associated with repeated exposure to latex, the prevalence may be as high as 60%. Children receiving home mechanical ventilation are frequently exposed to latex products. Therefore, we hypothesized that these children would be at increased risk for latex allergy. Fifty-seven children receiving home mechanical ventilation (31 boys, 26 girls; mean [+/- SD] age, 7.8+/-6.6 years; range, 0.3 to 23.2 years) were enrolled. A radioallergosorbent test (RAST) for latex was administered and serum IgE levels were obtained in all patients. Seventeen patients (29.8%) were found to have a positive RAST for latex. Patients with latex allergy had required mechanical ventilation for an average of 6.1+/-4.1 years vs. 5.5+/-5.4 years (p = 0.69; not significant) in those without latex allergy. Eleven of 17 patients (64.7%) had elevated serum IgE levels in the group with latex allergy vs only 14 of 40 patients (35.0%) in the group with a negative latex RAST (p = 0.04; odds ratio, 3.4). We conclude that there is a high incidence of latex allergy in children requiring home mechanical ventilation. We speculate that screening all children receiving home mechanical ventilation may lead to the identification of patients with previously undiagnosed latex allergy and the prevention of untoward reactions from exposure to latex.

Antigliadin IgE – indicator of wheat allergy in atopic dermatitis

Cereal grains are recognized as the cause of adverse reactions in some patients exposed to grain or flour by either inhalation or ingestion. Cereal-related diseases, such as celiac disease and baker's asthma, have been well studied and the causative cereal proteins have been characterized. Although cereals form an essential part of daily nutrition, the allergenic proteins causing symptoms on ingestion in atopic dermatitis (AD) have remained obscure. In this study, we have investigated the allergenic fraction of wheat in AD. Skin prick tests (SPT) with a NaCl wheat suspension and the ethanol-soluble wheat gliadin were performed on 18 wheat-challenge-positive or -negative children with AD, six adult AD patients with suspected cereal allergy, and one adult with wheat-dependent exercise-induced urticaria/anaphylaxis. Serum total IgE and specific IgE-antibody levels to wheat and gluten were measured with the radioallergosorbent test (RAST) simultaneously. In addition serum samples of all 25 patients were analyzed by IgE immunoblotting with the ethanol-soluble wheat-protein extract. Thirteen of the AD children were wheat-challenge-positive, 11/12 of them appeared to be positive with gliadin SPT, and all had an elevated gluten RAST value. Those challenge-negative were negative with both gliadin SPT and gluten RAST. Positive wheat SPT and RAST alone were not associated with positive challenges. Four of the adult patients responded to a cereal-free diet, although only two of them appeared to be positive with gliadin SPT and gluten RAST. A broad and intensive staining of gliadin peptides in IgE-immunoblotting studies was seen in challenge-positive children with positive gliadin SPT and/ or gluten RAST. Besides staining of peptides in the main gliadin area of 30-46 kDa, a characteristic finding was the staining of small, <14-kDa proteins with sera of challenge- and gliadin-SPT-positive patients. We found that wheat-allergic AD patients have IgE antibodies against gliadin that can be detected by both SPT and the sensitive immunoblotting method. This suggests that gliadin peptides are important allergens, and ingestion of wheat causes symptoms of AD. A broad and intensive IgE staining was seen of gliadin peptides against both the previously characterized peptides in the main gliadin area and small, previously uncharacterized peptides of less than 14 kDa. The gliadin SPT and gluten RAST are good screening methods. Further characterization of the IgE-stained gliadin proteins is needed.

Children with Acute Asthma: IgE Antibody Reactivities to Fungi, House Dust Mites, Cockroaches, and Other Indoor Allergens

ABSTRACT Allergens are known to be a significant cause of asthma. The aim of this study was to assess immunoglobulin E (IgE) antibody reactivity to fungi, basidiomycetes and fungi imperfecti, house dust mites, cockroaches, and other indoor allergens, in young asthmatics with acute asthma exacerbation. Forty-nine subjects (2.5 months to 14 years old, mean age 7.3 years) presenting to the emergency room with symptoms of acute asthma were tested for specific IgE antibodies to basidiomycetes, fungi imperfecti, German and American cockroach, cat, and house dust mites. Positive radioallergosorbent test (RAST) reactivity was most frequent (67.3%) and the greatest (up to 62.6%) to house dust mites. Children older than 5 years exhibited a substantial increase in mite-specific positive RAST reactivity compared to younger children. Frequency of IgE antibodies increased from 77% of subjects older than 2 years of age to 88% of subjects older than 6 years. The basis of this increase in mite reactivity after age of 5 ye...

Identification of Sunflower Seed IgE-Binding Proteins

Background: Sunflower seed can cause severe anaphylactic reactions in some susceptible individuals. It is conceivable that the 2S sunflower seed protein is an allergen based on its high degree of homology (34%) with the allergenic mature 2S albumin protein of the Brazil nut. The first step in determining the allergenicity of sunflower seed proteins is to identify IgE-binding proteins. Methods: Sera from sunflower seed-sensitive individuals were evaluated by radioallergosorbent test (RAST), isoelectric focusing (IEF) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting with sunflower seed proteins. Results: Positive RAST scores (>2) were observed in 3 individuals and immunoblotting demonstrated IgE-binding to 2–7 distinct proteins ranging in size from 10 to 50 kD. Two out of 3 sera recognized two proteins between 16 and 17 kD. The lower molecular weight protein (16 kD) approximates to the prepo region of the precursor methionine-rich 2S albumin protein found in sunflower seed (SFA-8/SSA). IEF followed by immunoblotting demonstrated several IgE-binding proteins, including two proteins with isoelectric points of 5.97 and 5.3, respectively, which are consistent with the mature and immature forms of the SFA-8/SSA region. Conclusions: Sunflower seed contains several IgE-binding proteins, including regions of the high-methionine 2S albumin SFA-8/SSA.

Randomized Controlled Trial of Advice on an Egg Exclusion Diet inYoung Children with Atopic Eczema and Sensitivity to Eggs

Lever R, MacDonald C, Waugh P, Aitchison TPediatr Allergy Immunol.919981319The role of exclusion diets in the management of atopic dermatitis (AD) in young children remains controversial. The aim of this randomized, controlled trial was to evaluate the effect of excluding egg from the diet in young children with AD and sensitivity to eggs.Fifty-five children with AD and egg sensitivity were randomized either to a 4-week egg exclusion diet (diet group, n = 28) or no diet (control, n = 27). The mothers of all children were given advice on the general care of eczema. Randomization for the dietary phase took place only after optimal control of the eczema was achieved and the child was stable on maintenance treatment (mean = 3.5 months). Disease activity was assessed by estimates of the surface area affected by eczema and by an arbitrary severity score. Possible egg sensitivity was identified by radioallergosorbent test (RAST) before randomization and after the trial by double-blind, placebo-controlled egg challenge.Overall, two thirds of the children with positive RAST results to egg experienced a positive reaction during double-blind challenge. After the dietary period, the dietary group experienced a significantly greater mean reduction in surface area affected by eczema than the control group (P = .02); from 19.6% to 10.9% area affected in dietary group compared with the 21.9% to 18.9% reduction in the control group. A significant improvement also was seen in the severity score (P = .04); from 33.9 to 24.0 units for the dietary group compared with a decrease from 36.7 to 33.5 in the control group. Egg-sensitive patients in the control group were then placed on a 4-week egg exclusion diet and also showed significant improvement in their severity scores.The authors concluded that advice on the dietary exclusion of eggs is useful as part of the overall management of young children with atopic eczema and sensitivity to eggs.Allergists and dermatologists continue to disagree over the role of allergic inflammation in children with AD. A recent study demonstrated that almost 40% of children presenting to a university dermatology clinic with moderate to severe AD have food hypersensitivity (see below). This study by Dr Lever and her dermatology colleagues demonstrates that removal of a food allergen from the diet of a food allergic patient leads to improvement in eczematous symptoms. In fact, it is somewhat remarkable that significant differences were observed in this relatively small number of patients, in such a short period of time, with the exclusion of a single food after an intensive topical steroid regimen. It would have been interesting to see whether a more complete dietary assessment and longer follow-up would have produced even more striking results, and information on whether a significant reduction in medication requirements occurred in the dietary group.

Sudden Infant Death Syndrome: A Search for AllergenHypersensitivity

Hagen LL, Goetz DW, Revercomb C, Garriott JAnn Allergy Asthma Immunol.801998227231Sudden infant death syndrome (SIDS) remains a diagnosis of exclusion with few clues as to its cause. Previous evaluations regarding anaphylaxis and SIDS are few and limited. The purpose of this study is to analyze forensic blood samples for evidence of anaphylaxis in children dying of SIDS against age-matched controls who died from defined nonanaphylactic causes.21 infants (13 males and 8 females) who died from SIDS were selected from a population of deaths investigated by the Bexar County Medical Examiner's Office between 1990 and 1995. Thirteen age-matched controls (9 males and 4 females) were identified who died from defined, nonanaphylactic causes.Frozen forensic blood specimens from these subjects were evaluated for the following: 1) total immunoglobulin E (IgE) (IU/mL); 2) latex, cat, dust mite, milk, soy, wheat, peanut, egg, and tomato specific-IgE radioallergosorbent (RAST) testing; and 3) serum tryptase levels (U/L). RAST test results were considered positive and potentially significant at measured counts >500.The 21 SIDS cases (median age, 3 months) and the 13 control cases (median age, 4 months) demonstrated similar total IgE levels of 9.8 ± 1.1 IU/mL and 19.9 ± 2.8 IU/mL, respectively, (P = .59). The frequency of detectable (0.5 U/L) serum tryptase levels among SIDS cases (10/51) were similar to controls ((3/13), P = .72). The frequency of positive RAST tests was 39% (20/51) in SIDS and 38% (5/13) in controls (P= .99). Differences in frequencies of positive RAST tests in SIDS and control cases were not statistically significant for any allergen that was tested. The most frequently detected allergen-specific IgE was to milk and was similar in the SIDS (22%) subjects and the controls (31%, P = .48).Elevated tryptase levels and allergen-specific IgE (milk, soy, wheat, peanuts, egg, tomato, dust mites, cat, and latex) were demonstrated in some of the infants who died from SIDS but were no more common than age-matched controls. It is therefore unlikely that anaphylaxis is a common cause in SIDS.There has been much study and debate over possible causes for the tragedy of SIDS. The anaphylaxis hypothesis has been put forth in several studies but never substantiated. This study relates that allergen hypersensitivity and anaphylaxis is unlikely to be a factor in this entitity. However, one must realize that total and specific IgE levels in infants are usually low compared with adults, and reference values for infant RAST interpretations are not standardized. Furthermore, tryptase often can be undetectable in cases of anaphylaxis and is not a definitive diagnostic tool. Nevertheless, this is a nice analysis of an important question. The authors propose that further study is required and desirable.

Evaluating the relevance of aeroallergen sensitization in atopic eczema with the atopy patch test: A randomized, double-blind multicenter study

Background: IgE-mediated sensitization of questionable clinical relevance is routinely demonstrated in patients with atopic eczema (AE) by skin prick test or radioallergosorbent test (RAST). We report the results of a randomized, double-blind multicenter study in patients with AE on the relevance and technical aspects of aeroallergen patch testing (atopy patch test, APT). Methods: Two hundred fifty-three adult patients with AE in remission were tested in 7 study centers on clinically uninvolved, unabraded back skin with 3000 to 10,000 PNU/g of Dermatophagoides pteronyssinus, cat dander, grass, birch, and mugwort pollen allergen extracts in petrolatum. After skin prick and RAST and a detailed history on aeroallergen-induced eczema flares was obtained, reading was done at 48 to 72 hours. Results: Previous eczema flares after contact with specific allergens were reported by 10% (mugwort pollen) to 52% (D pteronyssinus) of patients. The percentage of clear-cut positive APT reactions ranged from 44% with D pteronyssinus to 5% with mugwort. Positive skin prick (36% to 65%) and RAST (49% to 75%) results were more frequent. APT results showed significant concordances with history, skin prick, and RAST for D pteronyssinus, cat dander, and grass pollen ( P < .001). Optimal test concentrations were 5000 (grass pollen) and 7000 PNU/g ( D pteronyssinus , cat dander). The APT had a higher specificity (69% to 92% depending on allergen) with regard to clinical relevance of an allergen compared with skin prick test (44% to 53%) and RAST (42% to 64%). Conclusion: Aeroallergens are able to elicit eczematous skin reactions after epidermal application. The relevance of aeroallergens for AE flares may be evaluated by APT. (J Am Acad Dermatol 1999;40:187-93.)

In vitro lymphocyte proliferation in the diagnosis of allergy to phenoxymethylpenicillin.

The aim of this study was to investigate in vitro lymphocyte proliferation in the diagnosis of allergy to phenoxymethylpenicillin (PcV), comparing chemically reactive PcV, added to cell cultures in unconjugated form, to a PcV-PLL (poly-L-lysine) conjugate as antigens. Side-chain specificity of lymphoproliferative responses was investigated with reactive benzylpenicillin (PcG) and bacampicillin. Seventeen patients with a history of hypersensitivity reactions in connection with PcV treatment were studied by means of the lymphocyte transformation test (LTT), the radioallergosorbent test (RAST), skin tests (prick and intracutaneous), and oral challenge with PcV. LTT was also performed in 20 control subjects exposed to PcV therapeutically, and in eight subjects with occupational exposure to this penicillin. Nine patients had a positive in vivo test to PcV (five by oral challenge, three by intracutaneous test, and one by both tests), and six were challenge-negative. When reactive PcV was used as antigen in LTT, positive LTT responses were observed in five of the nine patients with a positive in vivo test, and two of them were also side-chain specific. Positive LTT responses with reactive PcV also correlated with a positive RAST in five of seven subjects. None of the six patients with a negative challenge test, and only one of the 28 controls showed a positive LTT result with reactive PcV. Thus, the specificity of LTT with reactive PcV was 96%. In contrast, when PLL-conjugated PcV served as antigen, four challenge-negative subjects and 11 controls were LTT-positive. The results of this study indicate that LTT with chemically reactive PcV could be useful as an in vitro complement in the diagnosis of PcV allergy and as a tool to reveal the side-chain specificity of peripheral blood lymphocytes. A positive LTT to PLL-conjugated PcV may be an indicator of immunization, but not necessarily allergy, to the penicilloyl structure.

Randomised controlled trial of brief neonatal exposure to cows’ milk on the development of atopy

OBJECTIVETo determine the effect of brief early exposure to cows’ milk on atopy in the first 2 years of life.DESIGNDouble blind, placebo controlled, randomised feeding intervention trial (Bokaal study).SETTINGDutch midwifery...

Comparison of Multi-Test device skin testing and modified RAST results

The initial purpose of this study was to determine the potential correlation between allergy test results obtained with the Multi-Test skin testing method and the radioallergosorbent test (RAST) blood test (used as a “standard”). Twenty patients with a history and physical examination findings suggestive of inhalant allergy underwent both a Multi-Test system screen (14 antigens plus histamine and glycerine controls) and RAST testing. The relationship between wheal size and Multi-Test system grade for each antigen and the corresponding RAST class was studied. The correlation between positive Multi-Test system and RAST results was poor, with an average agreement by antigen of 56.26% and overall agreement of 67.86%. However, the overall agreement between negative Multi-Test system results (≤1+) and negative RAST results (≤class I) was 95.15%, with an average agreement by antigen of 83.99%. On the basis of results of this preliminary study, it appears that a negative Multi-Test system result indicates that significant inhalant allergy is unlikely, whereas a positive Multi-Test system result necessitates follow-up with more definitive testing by additional skin testing or RAST. (Otolaryngol Head Neck Surg 1998;118:797-9.)