Positive Test Reactions Research Articles

A variety of skin responses to ultraviolet irradiation in patients with atopic dermatitis

Skin responses to ultraviolet irradiation in patients with atopic dermatitis were studied to evaluate the role of sunlight in the exacerbation of atopic dermatitis. A total of 15 patients, seven males and eight females, with atopic dermatitis who complained of exacerbation of their dermatitis after sun exposure were examined by photo testing with UVB and UVA irradiation and photopatch tests. Nine out of 15 patients showed abnormal skin reactions. Lowered minimal erythema doses (MEDs) to a single exposure of UVB, papular or erythematous responses after single or repeated exposures to UVB or UVA and positive photopatch test reactions to sunscreen ingredients and fragrances were found. There are apparently multiple mechanisms of photoexacerbation in patients with atopic dermatitis.

Occurrence of exercise induced bronchospasm in elite runners: dependence on atopy and exposure to cold air and pollen.

OBJECTIVES: To study factors affecting the occurrence of exercise induced bronchospasm (EIB) in elite runners. METHODS: Fifty eight elite runners, 79% of them belonging to Finnish national teams, volunteered. The...

Atopy in children with otitis media with effusion.

Contrasting data have been found on the prevalence of atopy in children with otitis media with effusion (OME). A major issue would be to determine whether screening for atopy should be recommended. Setting Centre for Study of Otitis Media with Effusion, Tabiano Terme, Parma, Italy. The purpose of this study was to investigate the relation of OME to atopy. The subjects were 172 children with OME and a control group of 200 children. The protocol included a questionnaire survey of diseases associated with atopy, a skin-prick test and a clinical evaluation of allergic symptoms and hypersensitivity to aeroallergens. No significant difference between patients and control group was observed for family history of atopy or positive skin-prick test reactions. Symptoms associated with atopy occurred significantly more frequently in the group with OME (P<0.001), though only the presence of rhinitis or atopic eczema was significantly associated with OME. Prevalence of positive skin-prick tests results is not enhanced in children with OME. Nevertheless, the association of OME with symptoms associated with atopy suggests that such concomitant diseases may play a part in the pathogenesis of the disorder. Children with allergic rhinitis or atopic eczema should be investigated by tympanometry for OME.

Sensitization to Blomia tropicalis among Asthmatic Patients in Taiwan

House dust mites have been reported as one of the most important allergens in Taiwan especially in asthmatic patients. This study was conducted to determine the allergenicity of Blomia tropicalis and sensitization of asthmatic patients in Taiwan. Serial dust samples were collected every month between July 1993 and June 1994 from 13 houses of mite-allergic patients. About 1 m² surface area of a quilt was vacuumed. The floating method was used to collect mites, then identification and counting were performed. Results showed that Dermatophagoides pteronyssinus and B. tropicalis were the two most common species of mites found in allergenic patients’ houses in Taipei. D. pteronyssinus accounted for 52.1% of the total number of mites and was found in every house. B. tropicalis, although not present in every sample, accounted for 44.3% of the total number of mites. The skin test positive reaction to B. tropicalis, D. pteronyssinus and Dermatophagoides farinae were 73.3, 88.3 and 85.0% as determined from 60 allergic patients who attended our allergy clinics. The extract prepared from B. tropicalis was used to determine the allergenicity and contained at least 30 protein components when silver stained. The most frequently detected allergens were proteins with molecular weights of 14.3, 106.5, 94.0, 72.0, 91.9, 63.7, 100.3, 43.6, 27.3, 62.0, 34.7, 18.3, 41.1 and 21.9 kD. The frequency of IgE binding of patient sera to those proteins were 87.0, 65.2, 56.5, 43.4, 39.1, 39.1, 34.8, 30.4, 30.4, 17.4, 17.4, 17.4, 13.0 and 8.7%. The results from immunoblot inhibition showed that there was IgE cross-reactivity among the B. tropicalis and D. pteronyssinus. However, there were two major allergenic components of B. tropicalis not inhibited by D. pteronyssinus with molecular weights of about 14.3 and 27.3 kD. The use of B. tropicalis extract for diagnostic purposes to identify patients with specific sensitivity should be considered in Taiwan.

TH2‐polarized immunological memory to inhalant allergens in atopies is established during infaney and early childhood

There is increasing evidence that the T-cell reactivity to environmental allergens underlying expression of allergic disease in adulthood, develops initially during childhood. However, there is little information available on the kinetics of these early responses, or on the patterns of cytokine production during this period. The purpose of this study was twofold: to obtain further information on the reported differences between responses to food versus inhalant allergens during early childhood, and to ascertain the age-range over which T-cell responses to inhalant allergens become polarized towards the TH2 cytokine profile, in potentially atopic children. In vitro cytokine responses to house dust mite (HDM) and egg (OVA) were assessed by semiquantitative RT-PCR in panels of 2- and 5-year-old children and adults; lymphoproliferative responses to OVA were subjected to epitope analysis. At age 2 years IL-4/IL-5 responses to HDM grouped with positive atopic family history, and by age 5 years cytokine responses correlated strongly with individual SPT reactivity to HDM. In contrast, OVA responses were restricted to weak and transient IL-5 signals in the 2-year-old family history positive group. Lymphoproliferation assays performed in parallel indicate a log-scale greater postnatal expansion of T-cell reactivity to the inhalant allergen; preliminary epitope analysis of OVA responses indicate that the number of OVA epitopes recognised decrease during early childhood. Inhalant allergen-specific in vitro cytokine production associated with positive skin-prick test (SPT) reactions, one of the hallmarks of adult atopy, manifests in children at or before 5 years of age; additionally, cytokine responses in SPT negative 5 year-olds are restricted to IFNgamma, as per normal adults. In contrast, T-cell responses to a typical food allergen appear to be deleted during early childhood.

Patch testing in the detection of cutaneous reactions caused by carbamazepine.

Carbamazepine is a widely used antiepileptic drug associated with various side effects including skin eruptions. Peroral provocation test with any suspected drug is a reliable method of investigating the etiology: however, it is both laborious and potentially dangerous to the patient. Patch testing has been reported with variable success in skin drug reactions. Four cases (one male, three females) with epileptic seizures were reviewed; all had received carbamazepine therapy with appropriate dosage, then suffered from various cutaneous reactions including maculopapular exanthema, exfoliative dermatitis, erythema multiforme and Stevens-Johnson syndrome after the initial therapy for two weeks to one month. Skin patch test was done with 1% and 10% carbamazepine in petrolatum applied on the back, then read at 48 and 72 hours. All four patients had positive allergic patch test reactions to carbamazepine. One patient had extreme (+3), one had strong (+2) and another two had weak (+) reactions. There were no any skin reaction to vehicle and control cases. This limited study demonstrates that patch testing may be useful in the detection or confirmation of any type of exanthematous eruption caused by carbamazepine.

C052 Drug and chemical photosensitivity

Photopatch testing was performed on 274 patients who had history of photosensitivity at the Institute of Dermatology Thailand from 1987 through 1989. A total of 92 positive photocontact reactions and 71 positive contact reactions were seen. The most frequent positive photopatch test reactions were to sulfanilamide (18.2%) followed by Jadit (4.4%) chlorpromazine (3.6%) promethazine (3.6%) and fenticlor (3.2%). The most common photodermatoses was polymorphous light eruption (60.9%). Photocontact dermatitis was established in 28 patients (10.2%) while other skin diseases aggravated by sunlight were seen in 47 patients (17.2%).

Prevalence of tuberculin skin test reactions among prison workers.

To determine the prevalence of positive tuberculin skin test (TST) reactions (10 mm or greater) among full-time employees of a provincial prison for women in Montreal. Participants underwent tuberculin skin testing and completed a self-administered questionnaire. Among 129 employees identified, 118 (91%) underwent tuberculin testing. Among 102 born in Quebec who completed the questionnaire, 33 (32%) had positive TST reactions, including 12 (23%) of 52 subjects who had never been vaccinated. Positive TST reactions were significantly associated in multivariate analysis with BCG vaccination after infancy (OR = 4.5, 95% CI = 1.5-13.5), years of work at other provincial prisons (OR = 2.5 for each 5 years of work, 95% CI = 1.2-5.2), travel to tuberculosis endemic countries (OR = 7.7, 95% CI = 1.4-43), although not with work in the prison for women (OR = 1.3, 95% CI = 0.9-1.9) The prevalence of positive TST reactions was greater among workers at a provincial prison for women than among a sample of students, suggesting increased occupational risk of tuberculosis infection.

Patient's Self-interpretation of Tuberculin Skin Tests

In the outpatient use of tuberculin skin testing (purified protein derivative [PPD]), it is at times inconvenient to have a patient revisit for interpretation. Therefore, we assessed patients' ability to self-interpret these test results. In keeping with prior custom, patients were seen by an experienced nurse, who performed skin testing with PPD intermediate strength as well as mumps and Candida anergy control tests in some cases, and explained the procedure. The patients were asked to return 48 to 72 h later, at which time one of the researchers recorded their test interpretations before they were again evaluated by the nurse. Sixty-eight patients were studied, of whom 59 returned at appropriate interval. Eighteen patients had a positive PPD test reaction of 10 to 20 mm induration, which only one patient correctly identified as a positive test result. However, positive anergy control tests were correctly interpreted in 10 of 27 cases. The small number of positive PPD test result recognition by these patients may be partially attributed to their lack of education, as well as foreign birth and denial of illness. PPD results should be checked by an experienced professional.

Contact allergy to the active ingredients of Bioban P 1487.

Bioban P 1487, consisting of the 2 active ingredients 4-(2-nitrobutyl)-morpholine (M) and 4,4'-(2-ethyl-2-nitro-1,3-propanediyl)-bis morpholine (DM), is a preservative recommended for mental working fluids. The aims of this study were to assess the frequency of contact allergy to Bioban P 1487, when added to a standard patch test series, as well as to test the individual active ingredients in patients sensitized to Bioban P 1487. Of the patients consecutively tested, 1.5% reacted positively to Bioban P 1487. Positive test reactions were noted in only 4 of 12 Bioban P 1487-sensitized patients tested with the individual active ingredients. Both active ingredients are contact sensitizers, but in most patients with this contact allergy it remains difficult to identify the sensitizing hapten.

Atopic eczema and other manifestations of atopy: results of a study in East and West Germany.

Within an environmental health study, dermatologic examination of 1273 pre-school-age children (5-7 years old) was carried out in selected areas of East (n = 287) and West (n = 987) Germany in spring 1991. On the basis of comparable genetic background, the influence of a different exposure to air pollutants on the manifestation of atopic diseases was investigated. Halle an der Saale (East Germany) and Duisburg (North/South) as well as Essen (West Germany) were chosen as polluted study areas, whereas the countryside town of Borken (West Germany) served as a control region. Outdoor pollution with particles and SO2 was significantly higher in Halle an der Saale. Of the total study group, 12.9% suffered from atopic eczema at the time of examination. The prevalence was highest in East Germany (17.5%; adjusted odds ratio [OR] 1.39, confidence intervals [GI] 0.77-2.52, compared to Borken). The reported frequencies of hay fever and asthma in the total study population were 2% and 1.3%, respectively, without significant differences between study sites. Some 34.7% of the children showed at least one positive skin prick test reaction; significantly (P < 0.001) higher sensitization rates were obtained in western regions (Essen, Duisburg-South) than in the control region (Borken) and East Germany. Multivariate analysis of the prevalence of atopic eczema showed associations with parental predisposition (OR 1.52, CI 1.03-2.25), sex (for boys, OR 0.63, CI 0.43-0.92), location (Duisburg-South vs Borken OR 0.52, CI 0.30-0.96), month of investigation (May vs April, and March vs February OR 0.55, CI 0.37-0.81), contact with rabbits (for girls, OR 2.90, CI 1.36-6.19), animal fur in bedrooms (2.17, 1.01-4.67), indoor use of gas without hood (1.68, 1.11-2.56), and distance of homes from a busy road (< 50 m 1.71, 1.07-2.73). Nonsignificant associations were observed for history of helminthic infections (OR 1.61, CI 0.98-2.64) and high parental education level (OR 1.83, CI 0.83-4.02). In East and West Germany, atopic eczema seems to follow a course different from that of respiratory allergic diseases and specific sensitization, a fact which underlines the need for a differentiated analysis.

Exposure-sensitization relationship for alpha-amylase allergens in the baking industry.

Fungal alpha-amylase is an important occupational allergen in the bakery industry. Epidemiologic studies focusing on the relationship between alpha-amylase allergen exposure and work-related respiratory allergy, however, have not been reported yet. In this cross-sectional study, sensitization to occupational allergens and work-related symptoms were studied in 178 bakery workers and related to allergen exposure. Alpha-amylase allergen concentrations were measured in personal dust samples, using a sandwich enzyme immunoassay. All workers were categorized into groups on the basis of their job histories and the alpha-amylase exposure levels of their job titles. Of all workers 25% had one or more work-related symptoms. As much as 9% of the bakery workers showed a positive skin prick test reaction to fungal amylase, and in 8% amylase-specific IgE was demonstrated. Alpha-amylase exposure and atopy appeared to be the most important determinants of skin sensitization, with prevalence ratios for atopy of 20.8 (95% CI, 2.74 to 158) and for medium and high alpha-amylase exposure groups of 8.6 (95% CI, 1.01 to 74) and 15.9 (95% CI, 1.95 to 129), respectively. Furthermore, a positive association was found between positive skin prick tests to alpha-amylase and work-related respiratory symptoms. In conclusion, this study has shown that there is a strong and positive relationship between alpha-amylase allergen exposure levels in bakeries and specific sensitization in bakery workers.

Allergic Contact Dermatitis From Doxepin Cream

Several topical antihistamines are known to cause contact allergy. Premarket predictive patch testing with doxepin cream showed it to have "low risk of irritation and sensitization" on normal human skin. In our patch test clinic, we routinely test topical preparations, and over a recent 1-year period, we patch-tested doxepin cream, the standard screening tray, and other topical preparations on 97 patients with various pruritic dermatoses. When possible, patients with positive reactions to doxepin cream were patch-tested with its ingredients, and repeated open-application use tests were also performed with the product. Seventeen patients had relevant positive patch test reactions to doxepin cream and 80 had negative reactions. In 13 of the 17 patients with positive reactions, the diagnosis of allergic contact dermatitis to doxepin cream was confirmed by positive patch test reactions to both the active ingredient and the whole formulation of doxepin cream, by an observed positive use test reaction to doxepin cream, or by both. Of 14 patients who completed testing with doxepin cream ingredients, all had positive reactions to the whole formulation, and 12 had positive reactions to doxepin hydrochloride. Repeated open-application use tests with doxepin cream on normal skin resulted in positive eczematous responses in eight of 10 patients. Eight of the 17 patients had concurrent, relevant positive reactions to other patch tests, especially to fabric-finish resins and to ingredients of other topical preparations. Many had long-standing dermatitis, and each had used doxepin cream for several days to 1 year. Two patients appeared to have had systemic contact dermatitis. Diagnostic patch test clinic experience illustrates that doxepin cream is a contact sensitizer on inflamed skin. Oral doxepin should be avoided in patients with doxepin contact allergy.

Effect of distance between sites and region of the body on results of skin prick tests

BACKGROUND: Two variables in skin prick testing were examined: the effect of a positive reaction to histamine or allergen on adjacent negative test sites and the relative size of reactions to allergen and histamine on the back and forearm. METHODS:Fifty-two subjects were tested on the back and arm with an allergen extract to which they reacted with a wheal of 8 mm or greater in diameter and with 50% glycerin at sites ranging from 2 to 7.5 cm distant from the allergen test site. A similar study was performed in 50 subjects by using 1.8 mg/ml histamine base to produce the positive reaction. The data were analyzed for the effect of a positive reaction on an adjacent negative control site and also for the relative size of positive reactions on the back and forearm. Data from a second study were also examined for the difference in reactivity on the back and arm. In this study 77 subjects underwent skin prick testing (in duplicate) with seven allergen extracts, 50% glycerin, and 1.8 mg/ml histamine base on the forearm and back. RESULTS: Positive reactions at the 50% glycerin sites were observed at a rate of 0.52% when defined as wheals of 3 mm in diameter or greater and at a rate of 1.11% when defined as flares of 10 mm in diameter or greater. There was no increase in the rate of false-positive reactions over the range of 2 to 5 cm distance from the sites of positive reactions to allergen or histamine. Fewer reactions were present at the 50% glycerin sites, 7.5 cm from the positive sites. The diameters of the reactions to allergen in the primary study were significantly ( p < 0.001) smaller on the forearms than on the back (27% less for the wheal and 14% less for the flare). The mean diameter of the wheals induced by histamine did not vary between back and arm ( p = 0.3); however, the mean diameter of the flares on the forearm with histamine were 8% smaller than those on the back ( p = 0.003). In the second study the reactions to cat extract ( n = 59) were significantly smaller on the forearm than on the back (mean wheal diameter 16% less, mean flare diameter 14% less, p < 0.001 for both). The reactions to histamine ( n = 76) in this study were also significantly smaller on the forearm (mean wheal diameter 6% less, p = 0.027, and mean flare diameter 14% less, p < 0.001). CONCLUSION: If a relatively nontraumatic technique for skin testing is used, adjacent positive test reaction sites of moderate size, which are 2 cm or more from the site of the prick test, are unlikely to cause false-positive reactions on either the back or forearm. Skin test reactivity is less notable on the forearm than on the back for both histamine and allergen. This effect was more pronounced for allergen tests (16% to 27% decrease in mean wheal diameter) than for histamine tests. (J A LLERGY C LIN I MMUNOL 1996;97:596-601.)

Skin test reactivity to recombinant Aspergillus fumigatus allergen I/a in patients with cystic fibrosis.

We evaluated the diagnostic value of recombinant Aspergillus fumigatus allergen I/a (rAsp f I/a) for skin testing in cystic fibrosis (CF) patients with allergic bronchopulmonary aspergillosis (ABPA), allergy to A. fumigatus and in CF controls not allergic to A. fumigatus. Skin prick test reactions to rAsp f I/a were 8.5-fold stronger in A.-fumigatus-allergic and 3.3-fold stronger in ABPA patients compared to the CF controls. Three out of 6 well-characterized ABPA patients had positive skin prick test reactions to rAsp f I/a; the same number reacted to crude A. fumigatus extracts. The skin prick test results to rAsp f I/a were significantly correlated with those to crude and commercial preparations. According to these results, rAsp f I/a represents a defined allergen that provides the possibility to perform skin prick tests in CF patients in a highly standardized way. In future, a larger panel of recombinant allergens might also pick up those CF patients with ABPA and allergy to A. fumigatus who did not react to this single allergen.

The development and course of test reactions to gold sodium thiosulfate.

In our department, gold sodium thiosulfate has become the 2nd most common allergen in routinely patch tested dermatitis patients, with a rate around 10%. Test reactions to this compound often appear late, sometimes so late that active sensitization may be suspected. This study was performed to study the time course of the allergic reaction to gold sodium thiosulfate and to elucidate whether late test reactions mean active sensitization. 10 patients with contact allergy to gold sodium thiosulfate (0.5% pet.) were retested epicutaneously (e.c.) and intracutaneously (i.c.) with dilution series. The clinical course was followed for 2 months with initially short intervals, later more extended. During the entire study, 26 positive e.c. reactions were diagnosed. Within the 1st week, 17 (65%) were recorded. 12 reactions (46% of 26) were noted at the ordinary reading, 3 days after test application. After 10 days, another 9 reactions (35%) appeared. The patients with the latter reactions also had positive test reactions within the 1st week. After 2 months, 9 reactions remained. Out of 30 i.c. tests applied, 25 became positive within 1 week. 19 (76%) of these reactions changed in morphology from thin infiltrates to deep nodules. Another 4 nodules appeared in patients with previous negative i.c. tests. All 23 nodules remained after 2 months. E.c. and i.c. test reactions to gold sodium thiosulfate are long-lasting. Positive patch test reactions emerging after 10 days do not automatically imply active sensitization. To diagnose contact allergy to gold sodium thiosulfate, the ordinary reading at day 3 is insufficient; even reading at 1 week is insufficient and must be supplemented by a reading at 3 weeks. All the i.c. test reactions, however, appeared within 1 week and, in several, a dermal nodule was formed.

Royal jelly–induced asthma and anaphylaxis: Clinical characteristics and immunologic correlations

temperature difference could be perceived either directly by elevated blood temperature affecting cells in the hypothalamic preoptic area, or indirectly by blood temperature first affecting peripheral neuronal receptors, which in turn stimulate the preoptic area. It would have been tempting to assume that direct heating of the blood could bypass peripheral neuronal receptors. However, because sequential skin temperatures were not recorded along with oral temperatures, this assumption cannot be established. Nevertheless, this case is a unique example of the temperature difference needed to be perceived by the central temperature regulation system in order to provoke the common efferent reflex leading to hives in CU.

Results of evaluation of 203 patients for photosensitivity in a 7.3-year period

Background: Although photosensitivity disorders have been well described, their incidence in a referral institution had not been studied. Objective: The purpose of this study was to evaluate the incidence of photosensitivity disorders, including photocontact dermatitis, in a academic medical center. Methods: The results of the assessment of 203 consecutive patients, all of whom had phototests, referred for the evaluation of photosensitivity disorders during a 7.3-year period were reviewed. Results: The mean age was 50 years, and 63% of the patients were women. The most frequent diagnoses were polymorphous light eruption (26% of the total patient population), chronic actinic dermatitis (17%), photoallergic contact dermatitis (8%), systemic phototoxicity to therapeutic agents (7%), and solar urticaria (4%). Positive photopatch reactions, patch test reactions, or both were observed in 40 (29%) of the 138 tested patients. The frequencies of the positive photopatch test reactions were sunscreens (57%), fragrances (18%), and antimicrobial agents (13%). Of the positive patch test responses, fragrances elicited 47% of the total positive reactions, followed by sunscreens (39%) and antimicrobial agents (7%). Conclusion: Polymorphous light eruption, chronic actinic dermatitis, and photoallergic contact dermatitis were the most frequently made diagnoses. Sunscreens, fragrances, and antimicrobial agents were the most common clinically relevant photoallergens and allergens.

Fc epsilon RI-beta polymorphism and risk of atopy in a general population sample.

To establish the prevalence of Fc epsilon RI-beta polymorphisms Leu181 and Leu181/Leu183 on chromosome 11q13 in the general population and to examine whether when maternally inherited they confer a risk of atopy. A population based survey for measures of atopy (skin prick test reactions, specific IgE titres, total serum IgE concentration), bronchial hyperresponsiveness, and carriage of Fc epsilon RI-beta Leu181 and Leu181/Leu183. The rural coastal town of Busselton, Western Australia. 1004 members of 230 two generation families identified through adults aged under 55. Fc epsilon RI-beta Leu181/Leu183 was identified in 45 subjects (4.5%). All 13 children who had inherited the variant maternally were atopic. Six had asthma and nine rhinitis. The odds ratio of a positive skin prick test reaction to house dust mite or grass pollen in these children compared with the other 523 children was 7.37 (95% confidence interval 1.62 to 33.60). The 95% confidence interval for the odds ratio of a positive specific IgE response (radio-allergosorbent test) was 3.00 to infinity, and the odds ratio for bronchial hyperresponsiveness was 3.70 (1.21 to 11.60). By contrast, the eight children who had derived the variant paternally had negative skin prick and radioallergosorbent test results and did not have increased bronchial responsiveness. Fc epsilon RI"' beta Leu181/Leu183 when inherited maternally identifies a genetic risk factor for atopy and bronchial hyperresponsiveness.

Prohevein from the rubber tree (Hevea brasiliensis) is a major latex allergen

There is general agreement that proteins eluting from different natural rubber latex products can cause immediate type hypersensitivity reactions in latex-allergic patients. However, there is as yet no consensus as to what are the most important allergens in natural rubber latex. We wanted to purify and characterize at the primary structure level three natural latex proteins, suggested to represent significant allergens. Proteins were purified from ultracentrifuged bottom fraction of natural rubber latex using high performance liquid chromatography gel filtration and reversed phase chromatography. Purified proteins were subjected to tryptic cleavage, peptide separation and amino acid sequencing. Immunoblotting was used to demonstrate IgE antibodies to the purified proteins in sera from latex-allergic patients. A 20 kDa protein was identified by amino acid sequencing as prohevein, a major protein in the rubber tree Hevea brasiliensis, and a 30 kDa natural rubber latex protein as hevamine, another essential rubber tree protein. A third, previously undescribed natural rubber latex protein, showed high homology to several plant endo-1,3-beta-glucosidases. In immunoblotting, the purified prohevein bound IgE antibodies from 24/29 (83%) sera of latex-allergic patients including positive results in 4/6 latex-allergic children with spina bifida or other congenital anomalies. The purified prohevein elicited positive skin-prick test reactions in all six latex-allergic patients showing IgE to prohevein. The purified 36 kDa protein bound IgE from 6/29 (21%) latex-allergic sera, and the purified hevamine from only 1/29 patient sera. The observed high frequency of IgE antibodies to prohevein suggests that this protein is a major natural rubber latex allergen.