Ara h 2 and Ara 6 are the best predictors of severe peanut allergy: a double-blind placebo-controlled study.

BACKGROUND: Component-resolved diagnostics offers a modern tool in peanut allergy, but studies applying consistently double-blind placebo-controlled challenges are lacking. We aimed to optimize diagnostics for moderate-to-severe peanut allergy in a birch-endemic region and to create an oral-peanut challenge with its allergen activity characterized. METHODS: We performed double-blind placebo-controlled peanut challenges for a referred sample of 6- to 18-year-olds with peanut sensitization or a high suspicion of peanut allergy, including anaphylaxis. We measured specific IgE (sIgE) to Ara h 1, 2, 3, 6, 8, and 9. Testing of allergen activity of the challenge products was by IgE microarray inhibition. RESULTS: Of the 102 patients, 69 were challenge positive: 25 (36%) had severe, 36 (52%) moderate, and 8 (12%) mild symptoms; 38 (37%) received adrenalin. SIgE to Ara h 6 AUC 0.98 (95%CI, 0.96-1.00) was the best marker of moderate-to-severe allergy. When sIgE to Ara h 2 and Ara h 6 was measured together, all (100%) severe reactions at low doses were successfully diagnosable. SIgE to Ara h 8 had no diagnostic value, AUC 0.42 (95%CI, 0.30-0.52). Both nonroasted and roasted peanut inhibited 100% of IgE binding to Ara h 1, 2, 3, and 6. Nonroasted peanut inhibited 87% of IgE binding to Ara h 8, roasted inhibited 30%. The products lacked Ara h 9 activity. CONCLUSION: Co-sensitization to Ara h 2 and Ara h 6 was associated with severe reactions distinguishing severe allergy from mild symptoms. SIgE to Ara h 8 added no diagnostic value. Component-resolved diagnostics reduce the need for oral challenges in peanut allergy.

Detection and characterization of atopic allergens.

The aim of the research of atopic allergens is to gather knowledge in order to be able to identify and to characterize environmental allergens and to develop better allergen preparations for diagnosis and treatment of IgE-mediated hypersensitivity diseases. Allergens or allergen activity can be detected and characterized with several in vivo and in vitro methods. In vivo tests measure the biological allergen activity, which is the most important characteristic of allergen preparations. Chemical and some immunochemical methods do not directly measure allergen activity, unless human IgE antibodies have been utilized. Since all these methods have their advantages and disadvantages, more than one method would be favourable in characterization of an allergen or an allergen preparation.

Banana allergy in patients with immediate-type hypersensitivity to natural rubber latex: characterization of cross-reacting antibodies and allergens.

BACKGROUND: An association between allergy to latex and banana has been reported. Even though cross-reacting IgE antibodies have been demonstrated, in no study has the existence of structurally similar allergens been confirmed. In the present study banana allergy was studied in a large series of patients with latex allergy. Specific IgE antibodies were characterized for cross-reactivity and compared with pollen RAST results. Latex and banana extracts were investigated for common antigens and allergens. METHODS: Latex-, banana-, and pollen-specific (birch, timothy, mugwort) IgE were measured in 47 sera from patients with latex allergy. Thirty-one patients were skin prick tested with banana and questioned for possible reactions after eating bananas. Several RAST inhibition and immunospot inhibition studies were used to characterize cross-reacting IgE antibodies. Structurally similar antigens and allergens were evaluated with crossed-line immunoelectrophoresis and crossed-line radioimmunoelectrophoresis, respectively. RESULTS: Latex RAST results were positive in 31 (66%) and banana RAST results were positive in 26 (55%) of the 47 sera. Of the 31 latex RAST-positive sera, 25 (81%) were also banana RAST-positive. Results from latex RAST correlated significantly with results from banana RAST (p < 0.001), but not with those from pollen RAST (p > 0.05). Banana skin prick test results were positive in 11 (35%) of the 31 patients tested. Symptoms after eating bananas were reported by 16 (52%) of the 31 patients. In inhibition studies the binding of IgE antibodies to solid-phase banana and to several latex preparations was inhibited by latex and banana, respectively. In crossed-line immunoelectrophoresis at least one antigen from banana fused with an antigen from latex, which also bound IgE antibodies in autoradiography (crossed-line radioimmunoelectrophoresis). CONCLUSIONS: Patients with latex allergy have symptoms caused by banana and show positive skin test and specific IgE test results. Cross-reacting IgE antibodies were confirmed by several inhibition techniques. For the first time, a structurally similar antigen/allergen was demonstrated.

Bovine beta-lactoglobulin levels in hydrolysed protein formulas for infant feeding.

A bovine milk protein, beta-lactoglobulin (beta LG), was measured by an enzyme-linked immunosorbent assay (ELISA) in seven different infant formulas based on protein hydrolysates from cows' milk whey or casein, and from bovine collagen and soy. beta LG levels in the formulas were 1/100 to 1/4,800,000 lower than in cows' milk (CM). There was a great difference in the beta LG level between the partly and the extensively hydrolysed formulas; the amount of beta LG was 40,000-fold higher in the partial hydrolysates vs the extensively hydrolysed formulas. Residual beta LG may have been responsible for the allergic reactions described in some children with cows' milk allergy (CMA) receiving these formulas.

A sensitive enzyme-linked immunosorbent assay for determination of bovine beta-lactoglobulin in infant feeding formulas and in human milk.

We developed a sensitive sandwich-type ELISA for measuring low levels of cow's milk (CM) beta-lactoglobulin. Purified anti-beta-lactoglobulin was used as coating antibody and also as second antibody conjugated with alkaline phosphatase. Polyethylene glycol 6000 was added to the incubation buffers to improve sensitivity. The detection limit of the assay was 0.002 microgram/l, which is much better than sensitivities reported for other beta-lactoglobulin assays. The sensitivity was not impaired by the presence of other CM proteins. The recovery from breast milk was 93% and from the diluting buffer 127%. The coefficient of variation within day was 5-15% and between days 10%. One hour after oral intake of milk, beta-lactoglobulin could be detected in the breast milk of three mothers at concentrations of about 1-2 micrograms/l. Widely different concentrations of beta-lactoglobulin were measured in two protein hydrolysates based on CM whey and casein proteins; the observed concentrations were 200 and 0.0056 micrograms beta-lactoglobulin/g dry weight, respectively.

Occupational asthma and rhinoconjunctivitis caused by senna.

Occupational sensitization to senna is seldom reported. We describe a 21-year-old male atopic factory worker who developed IgE-mediated asthma and rhinoconjunctivitis 5 months after exposure to senna while he was working for a company manufacturing hair dyes. In the bronchial challenge test with senna, he exhibited a strong reaction. The skin prick test gave a 12-mm wheal reaction. The radioallergosorbent test (RAST) with senna was highly positive (33.6 PRU/ml, class 4), and could not be inhibited with pollens or foods. In protein staining with SDS-PAGE, two heavy bands were detected in senna at about 14 and 25 kDa, and two faint bands were visible at 19 and 21 kDa, In IgE immunoblotting with the patient's serum, one heavy band was detected at about 16 and four faint bands at 23, 25, 28, and 38 kDa. The patient became symptom free after he had changed his job within the same company.

Rubber contact urticaria. Allergenic properties of 19 brands of latex gloves.

To compare the immediate skin test reactivity of various latex (natural rubber) surgical and cleaning gloves, prick tests were performed on 40 latex-allergic persons, 26 of whom were sensitized by surgical and 14 by cleaning latex gloves. 6/17 surgical gloves tested and 1/2 cleaning gloves caused positive reactions in almost all (over 87%) of the allergic subjects. In contrast, the frequencies of positive reactions to 4 other surgical latex gloves were as low as 8-21%, suggesting that not all surgical gloves are equally allergenic. Control prick tests with 1 synthetic rubber and 1 polyvinyl chloride (PVC) glove were negative in all subjects. 2 surgical latex gloves causing either a high or low number of positive prick tests in allergic subjects were analyzed with high-pressure liquid chromatography (HPLC). Similar allergenic protein fractions were detected, which showed protein peaks at MW 2000, 5000 and 30,000 daltons. Corresponding proteins were detected in 1 latex cleaning glove analyzed and in natural rubber. This result confirms that allergenic proteins persist in various surgical and cleaning latex gloves after manufacture from natural rubber and may cause contact urticaria symptoms in sensitized people.

Milk causes a rapid urticarial reaction on the skin of children with atopic dermatitis and milk allergy.

Open skin challenge test with whole milk and its large and small molecular fractions was performed on intact skin of children with atopic dermatitis and suspicion of milk allergy. Of the 51 children challenged with milk 35 reacted within minutes with contact urticaria. The large molecular (m.w. greater than 10,000 d) fraction gave an urticarial reaction as often as whole milk, whereas the small molecular fraction gave only a few positive reactions. These were obviously caused by alpha-lactalbumin which was present only in small amounts in the small molecular fraction. These findings indicate that immediate contact allergy to relevant food allergens can be very common in children with atopic dermatitis and that the large molecular antigens readily penetrate children's skin.

Occupational allergic contact urticaria to yucca (Yucca aloifolia), weeping fig (Ficus benjamina), and spathe flower (Spathiphyllum wallisii).

BACKGROUND: Occupational contact urticaria (CU) from plants is often reported, but it is less often attributed to decorative houseplants. We present an atopic gardener and caretaker of plants who developed CU when occupationally exposed to weeping fig, spathe flower, and yucca. METHODS: Sensitization was evaluated by skin prick tests (SPT) and analyses for IgE antibodies. RESULTS: SPT were positive to all three plants, and IgE antibodies were found to weeping fig and spathe flower. SPT were also performed with several decorative houseplants in more than 600 patients. Positive SPT was found to weeping fig (12%), African milk tree (8.3%), yucca (5.8%), Chinese rose (4.7%), massangana (4.6%), bird's nest fern (3.2%), and spathe flower (3.2%). CONCLUSION: Our study indicates that SPT and tests for IgE antibody are useful in detecting occupational CU caused by houseplants.

Characterization of latex antigens and allergens in surgical gloves and natural rubber by immunoelectrophoretic methods.

Allergy to natural rubber (latex) products is increasingly frequent among both medical personnel and lay subjects. Although individual antigens and allergens in latex products have not been fully characterized, they are believed to derive from the sap of the rubber tree. Rabbit IgG and human IgE antibodies against rubber proteins were used to characterize antigens and allergens in surgical latex gloves and natural rubber by crossed immunoelectrophoresis and its modifications. The results from crossed-line immunoelectrophoresis demonstrated that the surgical latex gloves had at least 10 antigens in common with natural rubber sap and ammoniated latex. In crossed radioimmunoelectrophoresis, at least six of the 10 protein antigens in the surgical glove extract and natural rubber were allergens since they bound IgE antibodies from the latex-allergic patients' sera. The surgical glove extract also demonstrated one allergen not found in natural rubber, suggesting that rubber proteins may be altered during glove manufacture.

Allergy to feathers.

Skin prick test reactivity to commercial and self-made feather-allergen extracts was examined in 269 consecutive adult patients with suspected allergic cutaneous or respiratory symptoms who had been referred to a university clinic. Some 177 subjects reacted to any inhalant allergen. Twenty-four (9% of the whole group and 14% of those positive to any inhalant allergen) reacted to commercial feather extracts from ALK (Hørsholm, Denmark), and 51 to any of the seven feather extracts used. Feather-mix RAST (Pharmacia, Sweden) was positive in three cases only. Skin prick test or CAP-RAST or both to house-dust mite were positive in 16 of those 24 subjects positive to the commercial feather extracts, but in only 23 of the 150 other atopic subjects (P < 0.001). A nasal challenge with a feather extract was made in 20 cases, always with negative result. In immunospot studies, concomitant allergy to feather-allergen extracts and house-dust mite could be demonstrated. Mite allergens in feather extracts were verified in RAST-inhibition studies. A clinically significant feather allergy was found in one patient only. The results suggest that true feather allergy is very rare, and most of the positive reactions seen in skin prick tests to feather extracts are probably caused by mite allergens present in feathers.

Cow's milk challenge through human milk evokes immune responses in infants with cow's milk allergy.

OBJECTIVES: In order to measure the immune response evoked in breast-fed infants with cow's milk allergy (CMA) by cow's milk challenge through human milk, mothers were given increasing doses of cow's milk after they had been on a cow's milk elimination diet. Another objective was to study the secretion of beta-lactoglobulin (BLG) into human milk before and during milk challenge in relation to the appearance of symptoms in infants. STUDY DESIGN: Seventeen asymptomatic mothers who had infants with challenge-proven CMA and 10 asymptomatic mothers who had healthy infants were recruited. Infants ranged in age from 1.8 to 9.4 months. A solid-phase enzyme-linked immunoassay (ELISPOT) was used to assess the total number of immunoglobulin-secreting and specific antibody-secreting cells. Flow cytometry was used to enumerate different lymphocyte subpopulations among peripheral blood lymphocytes primed during provocation by cow's milk antigens. BLG levels were assessed in human milk before the challenge and 1, 2, 3, and 4 hours after the commencement of the challenge. RESULTS: All but one of the infants with CMA showed symptoms of CMA during cow's milk challenge through human milk. There was a significant rise in the total number of immunoglobulin-secreting cells in the IgA and IgG classes associated with a positive cow's milk challenge response, but the proportions of peripheral blood B cells bearing CD19, CD23, CD19 and 23, CD5, or CD19 and CD5 were comparable. BLG levels were comparable in both study groups. CONCLUSIONS: Most of the infants with CMA reacted to cow's milk challenge through human milk. Hypersensitivity reactions to food antigens through human milk may be more common than previously thought.

Beta-lactoglobulin secretion in human milk varies widely after cow's milk ingestion in mothers of infants with cow's milk allergy.

BACKGROUND: Cow's milk proteins secreted in human milk may cause cow's milk allergy (CMA) even during exclusive breast-feeding. We studied beta-lactoglobulin levels in human milk of mothers of infants with CMA. We also studied intestinal absorption of macromolecules in the same mothers to see whether it is related to the secretion of beta-lactoglobulin in human milk. METHODS: CMA was verified with oral challenge in 46 of 55 infants assessed. beta-Lactoglobulin levels were assessed in human milk from 53 of 55 mothers of the infants before (basal sample) and 1 and 2 hours after an oral cow's milk load, which was given after a 24-hour milk-free diet. beta-Lactoglobulin was determined by an ELISA with a detection limit of 0.002 microgram/L. The 6-hour urine recovery of a high-molecular-weight polyethylene glycol (PEG) 3000 was assessed after an oral load of PEG in 45 of 55 mothers. RESULTS: beta-Lactoglobulin was found in the 1- or 2-hour samples in 75% of the mothers. beta-Lactoglobulin levels were increased in the 1- or 2-hour samples as compared with the basal levels in about half of the mothers. The respective levels were decreased in one third of the mothers whose basal beta-lactoglobulin levels were higher than in the others. beta-Lactoglobulin was found in none of the three human milk samples in 15% of the mothers. After an oral load of a high-molecular-weight PEG 3000, the 6-hour urine recovery of PEG was similar in the mothers of the infants with CMA and the mothers of infants without CMA. Neither was the urinary recovery of PEG related to the beta-lactoglobulin levels in human milk. CONCLUSIONS: The results support the view that beta-lactoglobulin in human milk may contribute to, but does not alone explain, the development of CMA in breast-fed infants.

Occupational allergy caused by spathe flower (Spathiphyllum wallisii).

Occupational allergy caused by plants is seldom reported although it is probably relatively common. We report on a 22-year-old male atopic caretaker of plants who developed IgE-mediated allergic rhinitis, laryngitis, pharyngitis, and contact and generalized urticaria caused by exposure to spathe flower (Spathiphyllum wallisii) while he was working for a firm that supplied plants to offices. He also had an asthmatic attack at work, but in bronchial provocation tests conducted 8 months after he had stopped doing the work in question, he developed rhinoconjunctivitis, pharyngitis, and laryngitis, but exhibited neither bronchial reaction nor fall in PEF values. Prick tests with spathe flower gave 3+ reactions for exudates from the flower, pollen, stem, and leaves. He also had several positive reactions to fruits, vegetables, and spices, but not to natural rubber latex. The radioallergosorbent test with spathe flower was positive (3.4 PRU/ml, close to class 3). In protein staining with SDS-PAGE, one heavy band was detected at about 14 kDa, and other faint bands were visible on both sides. Six faint bands were detected at the mol. mass range of 30-67 kDa. In IgE immunoblotting, one heavy band was detected at about 14 kDa. The patient became symptomless after he had ceased working with plants.

Skin prick tests and in vitro immunoassays with native spices and spice extracts.

BACKGROUND: Skin prick tests of native spices (commercial powdered spices) are common in patients with allergy to birch or mugwort pollen. Clinical symptoms from spices are infrequent but occasionally severe. OBJECTIVE: To compare the skin prick test results with native spices and spice extracts and to determine the clinical relevance of test material. METHODS: Skin prick tests with the native spices coriander, caraway, paprika, cayenne, mustard, and white pepper were made twice at 2-month to 2.9-year intervals in 49 patients. During the latter time, tests were also made with spice extracts and spice-specific serum IgE was measured. RESULTS: The reproducibility of skin test results with native spices was 67% to 100%. Spice extracts, except white pepper, elicited positive skin test reactions in half those with positive reactions to native spices. Higher specific IgE concentrations (> or = 3.5 PRU/mL) were seen in cases where the skin tests were positive to the corresponding spices with 5% extracts of > 8 kD Mw. Three-fourths of the patients with positive skin tests to native spices were positive to birch pollen and one-half to a vegetable. Mild clinical symptoms from spices were reported by one-third. CONCLUSIONS: Spice allergens partly crossreact with those of pollens and vegetables. A minority of spice allergens may give clinical symptoms. The > 8-kD 5% extracts may be relevant skin prick test materials for identifying patients at risk of developing severe symptoms from ingested spices.

Contact urticaria from protein hydrolysates in hair conditioners.

Protein hydrolysates (PHs) are added to hair-care products (to "repair" broken hair), soaps, bath gels, creams, etc. From one to 22 PHs used in hair-care products (collagen, keratin, elastin, milk, wheat, almond, and silk) were tested in three patient groups: A) 11 hairdressers with hand dermatitis B) 2160 consecutive adults with suspected allergic respiratory disease subjected to routine skin prick tests C) 28 adults with atopic dermatitis. In group A, all the 22 PHs were tested with scratch and patch tests. In groups B and C, one to three PHs were tested with prick tests. Positive scratch/prick test reactions were seen in 12 patients from three PHs altogether. All were women with atopic dermatitis, and all reacted to at least hydroxypropyl trimonium hydrolyzed collagen (Crotein Q). In three patients, prick and open tests with a hair conditioner containing Crotein Q were performed with positive results. One patient reported contact urticaria on her hands, and two reported acute urticaria on their head, face, and upper body from a hair conditioner containing Crotein Q. In seven of the eight studied sera, specific IgE to Crotein Q was detected. In conclusion, PHs of hair cosmetics can cause contact urticaria, especially in patients with atopic dermatitis.

Immediate contact allergy from hydrolyzed wheat in a cosmetic cream.

Immediate contact allergy to cosmetics seems to be rare, since only a few case reports on it have been published. We report on a case of IgE-mediated allergic contact urticaria caused by hydrolyzed wheat in a body cream.

Surgical latex glove allergy: characterization of rubber protein allergens by immunoblotting.

Immunoblot analysis employing IgE antibodies derived from sera of 3 physicians and 2 nurses allergic to surgical latex gloves, disclosed 10 allergens in natural rubber sap. Nine of the 10 allergens were detected in ammoniated natural rubber latex, but only 4 allergens in a latex glove extract. The allergenic proteins had apparent molecular weights ranging from 14 to 70 kD. Allergens with molecular weights of 14 and 21 kD showed the most intense immunoblot reactions suggesting that these proteins could be the major allergens in the natural rubber. An 11-kD protein and a 26-kD protein were only seen in the glove extract, indicating that they could be modified rubber proteins formed during glove manufacture.