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Allergic rhinitis and asthma are highly related to indoor and outdoor allergens. A common weed, Chenopodium album is one of these outdoor aero-allergens. In the literature, data about specific characteristics of children with C. Album sensitization is limited. In this study, we aimed to evaluate demographic and clinical characteristics of patients with Chenopodium album sensitization in a cross-sectional study. The patients and two control groups included in the study were found to be sensitized to Chenopodium album following skin prick tests in an allergy clinic over a period of one year. The patients and control groups completed a questionnaire consisting of items regarding demographics and clinical characteristics. The frequency of Chenopodium album sensitizationwas 9.4% (47/502). The distribution of these patients diagnoses was: 48.9% allergic rhinoconjunctivitis (ARC), 19.1% allergic rhinitis (AR), 12.8% ARC + asthma, 8.5% asthma, 4.3% asthma + AR. Allergic rhinoconjunctivitis was statistically higher than in the control groups (P: 0.008, P: 0.001). Allergic rhinitis symptoms and ocular symptoms occurred together in 51% during the pollination period of Chenopodium album, whereas 17% of the patients were asymptomatic between August-September. Forty percent of the patients had accompanying sensitization to animal dander (cat and/or dog dander), which was statistically high compared to control group 1 (P: 0.001). In conclusion, Chenopodium album sensitization is highly related to rhinoconjunctivitis. Children with ocular symptoms must be evaluated for Chenopodium album sensitization. These children can also be expected to have a high animal dander sensitization rate.

Identifying allergen distribution is meaningful and significant for effective diagnosis and treatment of allergic diseases. This study compared the allergen sensitivity in four southern China cities. We enrolled 55,432 participants (27,408 male, 28,024 female) between 2007 and 2019. The allergen-specific IgE levels were compared by the χ2 test. The five prevalent sensitivities were for mite mix (10,985, 19.82%), cockroach (4,860, 8.77%), crab (4,450, 8.03%), fish mix (3,874, 6.99%), and house dust (3,486, 6.29%). Almost all allergen sensitivities decreased with age, particularly from infant to middle aged participants (p < 0.05). An exception was Shenzhen, where food allergen positive rates remained constant in all age groups studied. The proportion of male sensitive to at least one food allergen (OR 1.130; 95% CI 1.088-1.174, p < 0.0025) or aeroallergen (OR, 1.117; 95% CI, 1.078-1.158, p < 0.0025) was higher than female in all four cities. Except for dog dander and tree mix, all aeroallergens differed significantly between seasons (p < 0.05). Liuzhou had the highest rates of food allergen- and aeroallergen-positive participants. The allergen-specific IgE distribution differed among the studied cities, with significant seasonal differences. Young age, male sex, and aeroallergens were risk factors for allergic disease.

Few studies shed light on trans-regional differences in allergen sensitization between vast regions within a similar latitudinal range but with distinct geomorphological features. We aimed to detect specific IgE (sIgE) positivity to common allergens in populations from two southern China provinces. Using a uniformed protocol, serum was collected from 2778 allergic patients in coastal Guangdong and inland Yunnan, and examined for sIgE to local allergens including house dust mite, cockroach, tree pollen mix, mold mix, dog dander, crab, shrimp, egg white and milk. The overall sIgE positive rates were 58.4% in patients from Guangdong vs 61.0% from Yunnan. House dust mite (d1) was the most common allergen in both regions, figure 1. Among d1-sensitized patients, only 35.7% (208/583) in Guangdong and 22.9% (147/642) in Yunnan tested positive for house dust mite alone. Among those poly-sensitized d1-positive subjects, cockroach was the most common co-sensitizing aeroallergen in either province. 41.9% of the d1-sensitized Guangdong subjects had class 4 or higher response, in drastic contrast to a very low percentage of such reactivity in Yunnan subjects. However, a high proportion of d1-sensitized patients in Yunnan (36.3%) were concomitantly positive for tree pollen mix, figure 2. Surprisingly, Yunnan patients showed high sIgE-positive rates for crabs and shrimps, either by an overall or by age-group analysis, compared with their Guangdong counterparts (both P

U Kack, A Asarnoj, H Gronlund. J Allergy Clin Immunol. 2018;142(4):1113–1120.e9 To analyze patterns of immunoglobulin E (IgE) reactivity to dog allergen components in sensitized children and investigate the association between those patterns and clinical symptoms by nasal provocation tests (NPT). Children 10 to 18 years ( n = 60) with known sensitization to dog identified by a skin prick test wheal >3 mm or serum-specific IgE >10 kU/L were included. NPTs were performed with a commercial dog extract by using a standardized protocol. The extract was analyzed by radioallergosorbent test inhibition and contained all 6 dog allergens (Can f 1, 2, 3, 4, 5, and 6) used in subsequent analyses. The allergens were present in a wide range of concentrations. Serum-specific IgE levels to dog extract and each of the allergenic components were measured. All but 2 children had allergic rhinitis or conjunctivitis, and 41 out of 60 …

Mechanical laundry is an effective tool for the environmental control of allergens, but the optimal conditions for removing allergens are not yet clear.To evaluate the optimal conditions of mechanical laundry for the removal of house dust mite (HDM), dog dander, and pollen allergens.The 4 washing modes of 30 degrees C (86 degrees F), 40 degrees C (104 degrees F), 60 degrees C (140 degrees F), and steam water (SW) with detergent were evaluated. Allergen removal performance was assayed using a 2-site enzyme-linked immunosorbent assay (ELISA) or an ELISA inhibition test.Using the 30 degrees C and 40 degrees C washing modes, only 6.5% and 9.6% of Dermatophagoides farinae, respectively, were killed. However, using the 60 degrees C and SW washing modes, all HDMs were killed. The amounts of Der f 1 remaining after the 30 degrees C, 40 degrees C, 60 degrees C, and SW washing modes were 26.8%, 2.4%, 1.3%, and 0.6%, respectively, with unmanipulated contaminated sheets. The effects of rinse on Der f 1 levels after the 30 degrees C washing were greater compared with those after the 40 degrees C, 60 degrees C, and SW modes. The amounts of Can f 1 in the extractions after washing were 0.3% to 1.3% for all modes, and all extracts, even without a rinse, did not inhibit specific IgE binding to dog allergens according to ELISA. The remaining pollen allergen levels after washing were lower in the 60 degrees C and SW modes than in the lower temperature modes. However, the levels did not differ among the various washing modes after rinsing once.Water temperature and number of rinses are critical factors for the removal of HDM, dog dander, and pollen allergens.

To survey airborne and food allergen patterns in southern Taiwan and to analyze the effect of age on response to different allergens, we tested samples from 4,411 allergic patients at Kaohsiung Medical University Hospital using the MAST-CLA test (new Taiwan panel). A total of 2,212 (50.1%) samples showed a positive response. We grouped allergic patients into five age groups. Milk and egg white were the main food allergens in the younger groups (< 3 years old and 3-6 years old). Shrimp, crab, and shellfish were the main allergens in the groups aged 7-12, 13-18, and more than 18 years. Among airborne allergens, house dust and mites Dermatophagoides farinae and D. pteronyssinus were the main allergens in all age groups, whereas the frequency of response to cockroach allergen was low in the group aged less than 3 years, but increased in the other age groups. There was a sharp increase in the frequency of response to airborne allergens after 3 years old and a sharp decrease in response to food allergens. Among subjects allergic to both airborne and food allergens, there was a positive MAST-CLA rate of 19.9% to 26% (all five age groups, no significant difference). When we compared our results with those from Taipei Veterans General Hospital in northern Taiwan, there were significant differences for yeast, peanut, feather mix, dog dander, cockroach, D. farinae and D. pteronyssinus allergens (p < 0.01). These differences were probably caused by differences in patient location, patient age, disease patterns and allergen panels.

Two in vitro assays for the detection of allergen-specific IgE (sIgE) were compared reestimating sera with sIgE to common inhalants (birch t3, timothy g6, mugwort w6, cat dander el, dog dander e5, housdust mite D. pter. dl) and food allergens (FA) (hen's egg fl, cow's milk f2, wheat flour f4, soy bean f14, hazelnut f17, apple f49). Quantitative values (kU/l) of both systems were associated to different degrees depending on the allergen: allergen/n t3/48, g6/47, w6/39, e1/40, e5/42, d1/39. Spearman's rho 0.95***, 0.9***, 0.82***, 0.9***, 0.82***, 0.85***, allergen/n f1/37 f2/38 f4/68 f14/52f17/40 f49/40. Spearman's rho 0.84***, 0.6***, 0.6***, 0.31*, 0.68***, 0.82***, *** p < 0.001; * p < 0.05. Values to inhalants (t3, g6, el, e5) were scattered moderately around an ideal regression line (diagonal between x-and y-axis). In contrast, sIgE-levels to FA (f2, f4, f14, fl7) showed stronger discrepancies between both systems. Similarly, different degrees of association and spreading, depending on the individual allergen, were found comparing semiquantitative classes (0 - 6) of both systems. Taken together, values of sIgE to inhalants detected by different in vitro methods are stronger associated than sIgE to FA; IgE-values to allergens with one dominant major allergen (i.e. t3, el) seem to be more concordant than complex allergen mixtures (i.e. dl); identical units (kU/l) can not garantee equivalent IgE results. The data presented do not allow estimates of the real IgE concentrations or judgement on superiority of one of the tests over the other. The study is restricted to compare both methods analytically, since the diagnostic concordance could not be calculated due to a lack of corresponding clinical data. Despite these limitations, comparative sIgE studies are necessary and helpful to define the concordance of IgE values detected by different immunoassays. They also set the basis for subsequent improvement of allergens used in test systems detecting specific IgE.

Background and methods: Dog dander is one of the most important indoor allergens in Nordic countries. Due to the population flow into cities, the number of dogs in urban areas has increased. Dog allergens can be found practically everywhere indoors. We measured allergen content in indoor air and dust during dog shows. Results: In facilities used for dog shows, the dog allergen content was exceptionally high, up to 2 100 000 ng Can f 1/g dust, but it can be reduced by proper cleaning. The efficiency of cleaning will remain poor if furniture and textiles are not cleaned or the distribution of airborne allergen cannot be prevented. Conclusions: Dog shows should not be held in public facilities, such as schools, where a significant proportion of occupants are hypersensitive to dog allergens and may therefore suffer symptoms due to the exposure to dog dander.

Sensitization to dust mite allergens can be determined by means of a skin-prick test (SPT) or by measurement of specific IgE antibodies in serum (sIgE). In our study, concordance of the results of both methods was analyzed on the basis of reproducible SPT results. Three consecutive SPTs were performed on 138 school children (age 6-8 years) at one-year intervals. SIgE was determined at the end of a two-year observation period. Seven common inhalant allergens (Dpt, Df, birch pollens, hazel pollens, grass pollens and cat and dog dander) were analyzed. The majority of subjects with positive SPT reactions to the respective allergen also showed sIgE (Dpt: 82/86; Df: 53/53; cat dander: 31/32; dog dander: 6/9; birch pollens: 29/31; hazel pollens: 22/22; grass pollens: 37/37). A significant correlation between the SPT [weal diameter (P1) or allergen/ histamine ratio (P2)] and sIgE was found for Dpt (P1 = 0.004/ P2 = 0.016), birch pollens (P1 = 0.002/P2 = 0.0001) and grass pollens (P1 = 0.0005/P2 = 0.0001). There was also a significant correlation between sIgE to Dpt and to either Der p 1 (p = 0.0001) or Der p 2 (p = 0.0001), as well as between sIgE of both major allergens (p = 0.0001). In the analysis of co-sensitization of Dpt and Df, most subjects sensitized to Dpt were also sensitized to Df (57/91). Children with sIgE to Dpt (n = 87) usually showed sIgE to Df(n = 83). In this study, SPT and sIgE results are concordant and appear equivalent when using reproducible SPTs. Therefore, in the case of a positive Dpt result, additional testing for sensitization to Df can be regarded as redundant when Dpt and Df are the major contributors to the allergen content of house dust.

BACKGROUND This study evaluated the diagnostic performance of naturally purified allergen-molecules compared to that of allergen-extracts for house dust mite, cat dander epithelium and dog dander. METHODS In vitro tests for allergen-specific IgE were performed on the IMMULITE(®) 2000 in serum samples from 66 allergic patients. RESULTS House dust mite: specificity for the allergen-extract (D1) and the allergen-molecules (nDer p 1, nDer f 1, nDer p 2 and nDer f 2) is comparable. The allergen-extract has a significantly higher sensitivity (100%) and total agreement (TA) (93%) relative to sensitivity (57%-70%) and TA (76%-81%) of the individual allergen-molecules. Cat dander epithelium: sensitivity (90%), specificity (96%) and TA (94%) of the allergen-molecule (nFel d 1) are comparable to those of the allergen-extract (E1). Dog dander: The allergen-molecule (nCan d 1) and allergen-extract (E5) have comparable specificity and TA. The allergen-extract has a lower sensitivity (52%) than the allergen-molecule (71%), although not significant (p=0.125). CONCLUSIONS There is no diagnostic benefit of using allergen-molecules instead of allergen-extracts for initial allergy screening on cat dander epithelium and dog dander. However, use of these allergen-molecules might contribute to better standardization of the specific IgE tests. The studied allergen-molecules for house dust mite are of minor diagnostic value, because of loss of sensitivity.

In clinical work I formed the impression that the potency of Phazet lancets, for cat and dog allergens, was lower than earlier and too low to diagnose all clinically sensitive children with cat and dog allergy. Therefore, I decided to investigate the potency of newly produced and several years old Phazet lancets coated with dog and cat allergens. Twenty-six adults with case histories of cat and/or dog allergy and skin reactive to extracts of either dog dander or cat epithelium were skin prick tested in duplicate with one old batch and one newly produced batch of Phazet dog and/or cat lancets as well as the in-house reference of cat and/or dog allergen, 100,000 BU/ml. The potency of Phazet lancets in relation to the standard was evaluated by the median slope of the allergen dose-response relationship. The potency of the old dog lancets (mean 48,900 BU/ml) was higher (NS) than that of the newly produced lancets (mean 28,000 BU/ml), and the potency of both types of lancets was significantly less (P < 0.001) than that of the dog allergen in-house standard. On the other hand, the potency of newly produced (123,000 BU/ml), but not old (108,000), cat-allergen-coated Phazet lancets was higher than that of the cat allergen in-house reference extract (P = 0.048). There was a marked variation in potency between patients. Most of this variation was due to factors varying between patients, not between lancets, indicating that the composition of the allergen on the lancets was partly different from that of the standard.(ABSTRACT TRUNCATED AT 250 WORDS)

Background Little information or data are available concerning the stability and compatibility of dog epithelia and dog dander allergens. Objective To determine the immunochemical reactivities of commercial, nonstandardized dog epithelia and dog dander extracts after exposures to various temperatures or after mixing with high-protease fungal and cockroach extracts at concentrations recommended for maintenance immunotherapy (IT) injections. Methods Quantitative enzyme-linked immunosorbent assay and qualitative (immunoblot) analyses were performed to compare specific compositional changes with total or individual allergen activities. Assays for dog allergens Can f 1 and Can f 3 (albumin) used specific mouse or rabbit antibodies. Multiallergen enzyme-linked immunosorbent assay inhibition and immunoblot methods were conducted using a human serum pool with high levels of IgE to dog allergens. Results Dog allergen recoveries ranged from 22% to 134% after short exposures to moderate or extreme temperatures and from 28% to 118% after mixing with fungal or insect extracts and storage for up to 15 months at 2°C to 8°C. Recoveries in dog dander extracts varied up to 2.5-fold with different test methods. Immunoblots revealed partial degradation of dog albumin molecules to discrete fragments that retained antibody-binding activities. In most cases, recoveries improved at elevated glycerin concentrations. Conclusions Dog allergens in epithelia and dander extracts exhibited favorable temperature stabilities. Compatibilities with fungal or insect extracts may be compromised or at risk in some combinations. These data support current IT practice parameter recommendations of separating high-protease extracts from other products if possible; they also demonstrate that dog extracts possess allergen stabilities suitable for many IT formulations.

Fruits belonging to the Cucurbitaceae family 1 have been reported to be one of the most important allergycausing fruits in the United States. To the best of our knowledge, although pumpkin is a member of the above family and allergy to roasted pumpkinseed has been described, we have not found any indexed report concerning allergy to this fruit. The aim of our study was to describe the clinical and immunologic findings in this first reported case of allergy to pumpkin. CASE REPORT The patient was a 28-year-old woman with a history of rhinoconjunctivitis and asthma who was allergic to pollens and cat dander. She was referred to our clinic after development of several episodes of itching of the mouth, angioedema of the lips and face, generalized itching, and mild dyspnea within 15 minutes after eating pumpkin soup or thin vermicelli (sweet made from the fibrous part of the pumpkin). The patient required treatment with inhaled bronchodilator, antihistamines, and methylprednisolone in the emergency unit. She had not consumed any other food, beverages, or drugs coinciding with these episodes. In vivo tests Skin prick tests to an aeroallergen commercial battery (pollens, mites, fungi, and cat and dog dander) according to European Academy of Allergology and Clinical Immunology (EAACI) guidelines were positive to cat dander and most of the tested pollens (grasses, trees, and weeds). The skin prick-by-prick test responses with fresh fruits were positive to pumpkin (10 × 9 pseudopoda) and also to other Cucurbitaceae fruits: cucumber (5 × 4 mm), zucchini (4 × 3 mm), muskmelon (7 × 6 mm), and watermelon (7 × 3 mm). The open oral challenge test response to fresh pumpkin, according to the previously described method, 2 was positive, and it was also positive for cucumber, muskmelon, and watermelon. In vitro assays The pulp of several Cucurbitaceae fruits was processed according to the method previously described. 2 The initial protein content of the extracts was enriched by a method based on ion-exchange chromatography.3 The protein concentration of all fruit allergenic extracts was adjusted to 1 mg/mL.

Results: The sensitization rates to Tree pollen mixture I and II were increased as 5.0%, 6.8% in 2000, 8.5%, 9.8% in 2005, and 14.8%, 17.3% in 2010, respectively (trend P < 0.001, P < 0.001, respectively). And the sensitization rates to D. pteronyssinus cat dander and dog dander were changed as 55%, 4.8%, 4.8% in 2000, 62.2%, 11.9%, 28% in 2005, and 63.1%, 12.7%, 16.7% in 2010, respectively. The distribution of sensitized pollens was oak (12.8%), beech (12.4%), pine (10.3%), birch (10%), hazel (9.6%), alder (8%), elder (6.9%), elm (5.4%) in the study of 2010. When allergen/histamine ratio was compared, rates of strong sensitization over 4+ to tree pollen were increased. Conclusion: The sensitization rates to inhalant allergens were increased in children with asthma or allergic rhinitis from a tertiary re- ferral hospital in Seoul over last 10 years. Especially, an increase in the degree of skin reactivity was observed in cat dander, dog dan- der, and tree pollens. The studies to investigate the etiology of this increase and prevention will be needed. (Allergy Asthma Respir Dis 2014;2:97-102)

PURPOSE: The higher prevalence of respiratory allergic disease may be due to increased exposure to inhalation allergens. We conducted a survey of allergic diseases in autumn and winter with detection of major indoor allergens in major cities in Korea. METHODS: We enrolled 110 subjects from the fourth Korea National Health and Nutrition Examination Survey with stratified, cluster, and systematic sampling procedures. All participants answered a health questionnaire as well as underwent a skin prick test (SPT) and ImmunoCAP for 11 indoor major allergens. We also measured the levels of 5 major allergens (Der f 1, Der p 1, Can f 1, Bla g 1, and Asp f 1) in fine indoor dust from the houses of 60 subjects with a 2-site ELISA. RESULTS: The prevalence of allergic rhinitis and asthma were 25.5% and 7.3%, respectively. The most common sensitized allergens identified by SPT and ImmunoCAP were Dermatophagoides farinae (40.9%, 36.8%), followed by cockroach (23.6%, 19.5%), mugwort (13.6%, 22.9%), oak (9.1%, 22.9%), Japanese hop (9.1%, 8.6%), and dog dander (8.2%, 6.9%). There was a modest discrepancy between SPT and ImmunoCAP. Der f 1 and Der p 1 were detected in 91.7% and 45.0% of the enrolled houses, respectively. Der f 1 indicated high concentrations in all specific provinces in Korea; however, Der p 1 measured high only in the south. Dog dander allergens were present in 71.7% of houses; however, Bla g 1 was present in only 11.7% of houses and Asp f 1 was not detected in any houses. CONCLUSIONS: The most important inhalant allergens in Korea are house dust mites followed by cockroach, mugwort, oak, Japanese hop, and dog dander in indoor environment, in which The dominant species of house dust mites were different according to region.

Rationale This transversal study aimed to establish the possible differences of cutaneous sensitization to common aeroallergens in patients under 14 years-old. Methods This study was conducted from 1998 to 2002 on 3047 patients, from the Southwest of Madrid region (Spain). These patients were referred to our allergy unit due to respiratory symptoms (rhinitis and/or asthma). The first skin prick tests (SPT) to the most common aeroallergens in our environment performed to each patient were analyzed. A SPT of 3 mm larger than saline was considered positive. Patients were classified into seven age groups: 0-1 (n=16), 1-2 (n=42), 2-3 (n=124), 3-4 (n=177), 4-5 (n=245), 6-10 (n=1238), 11-14 (n=1205). Results 56.1% of patients were male. The prevalences of sensitization found were as follows: grass pollen: 52.8%, olive pollen: 41.5%, D. Pteronyssinus: 8.6%, dog dander: 19.5%, cat dander: 21.8%, alternaria: 13.5%, cockroach: 2.4%. The prevalence of positive SPT for each allergen was different among the age groups (p Conclusions In our study, cutaneous sensitization begins in the 2nd year of life and the maximum appears in the 10-14 years-old group. No gender differences were noted except in grass pollen, in patients older than 4 years-old.

The results of the skin, bronchial or conjunctival provocation tests and of the radioallergosorbent test (RAST) with dog dander and hair extract preparations from two different producers were compared, 202 asthmatic children were included in the study. The clinical tests, Al-RAST and paper RAST. were performed using only one allergen preparation (Hu 073), while two allergen preparations (e2 and e5) were used in Phadebas® RAST. A good correlation was generally found between the results of the clinical diagnostic tests, the clinical history and the results of RAST. Phadebas RAST e2 was the most specific but the least sensitive: it gave a class 0 result in 18% and class 3–4 in 34.5% of the subjects with a positive provocation test. The corresponding numbers for e5 RAST were 6.0% and 70.2%, respectively. Al-RAST was equally sensitive, but had lower specificity than Phadebas RAST e5. The correlation between Phadebas RAST e5 and paper RAST Hu 073 was excellent, which indicates a remarkable similarity between these allergen extracts. Using sensitive, immunochemically standardized Phadebas RAST e5 or Al-RAST methods, classes 0–1 can be regarded as negative, class 2 as doubtful and classes 3–4 as clinically positive results.

The commercial cat and dog allergen extracts are traditionally prepared from pelt, fur or dander. However, there is increased evidence of the allergenicity of saliva and urine of the animals. We have investigated 25 asthmatic children with a positive cat and/or dog RAST result. All 20 subjects with a positive cat RAST gave a positive skin prick test result to cat saliva, cat urine and cat hair. Analogously, all 20 subjects with a positive dog RAST had a positive skin reaction to dog saliva, urine and dander. In RAST inhibition experiments with dog and cat allergen discs, dog saliva appeared to be at least as potent as a commercial dog dander and hair extract, while cat saliva was less potent than the respective commercial extract. Both dog and cat salivas were clearly more potent than the respective urine. Significant cross-reactivity was observed between cat hair and dog dander in the RAST inhibition, whereas saliva and urine were shown to be more species-specific. An experimental dog dander preparation had about the same specificity as, and even higher allergenic activity than, that of dog saliva or urine. Our results suggest that saliva actually may be the best source of cat and dog allergen preparations. The importance of urine warrants further investigation.

Summary Skin prick tests (SPT) were carried out on 164 asthmatic children using dog dander allergen preparations (A, B1, B2 and D) from three manufacturers. Bronchial and/or conjunctival provocation tests with allergen A were performed on all patients, as well as the Phadebas® RAST (allergen e5). There was a close agreement between the clinical history and the SPT with allergens A and D. The provocation tests and RAST gave results in good agreement with the SPT reactions to all allergens except B1. The overall agreement between the SPT reactions to the different allergens was good. However, significant differences were observed in the allergenic activity of the different preparations and between different batches from the same manufacturer (allergens B1 and B2).

Serum total and allergen-specific IgE and IgG4 antibodies, were measured in eighty-seven atopic and nineteen non-atopic asthmatics. The allergens studied were: Dermatophagoides pteronyssinus, grass pollens, cat dander, dog dander, milk and egg. Sixty-eight atopic asthmatics and fourteen non-atopic asthmatics were found to have allergen-specific IgG4 antibodies, to at least one of the allergens tested. IgG4 antibodies to milk and egg were common in both groups of asthmatics, and to animal danders in the non-atopic asthmatics. Skin prick tests were always negative when allergen-specific IgG4 antibodies occurred alone, but in such cases, intradermal skin tests were positive. Seventy-five per cent of a group of patients with normal levels of serum total IgG4, were found to have at least one positive IgG4 RAST.

A double-sandwich enzyme immunoassay (DSEIA) was developed for the detection of human IgG antibodies to dog dander and hair (DH) allergens. Since DH allergens are immunogenic in rabbits, the gamma-globulin fraction of rabbit antiserum to DH (RGG-a-DH; 10 μg/ml) was used for coating of polystyrene microtiter plates. Dog allergens (1 μg/ml of DH extract) were bound to RGG-a-DH. Binding of human IgG Ab to nonimmune RGG (10 μg/ml) – used as a background control – was substracted from the DH specific one and nonspecific binding was further eliminated by using 0.5% of normal rabbit serum in the dilution buffer. Sera were diluted 1:10 in this buffer. Specificity of the assay was shown by absorption experiments: protein A, anti-IgE discs (Phadebas® PRIST) and dog or birch (e5, t3; Phadebas® RAST) allergen discs were used to remove total and allergen specific IgG and IgE, respectively. The results were expressed as net absorbances or as a percentage of a reference serum. A significant correlation (r = 0.65, p