Risk factors for latex allergy in patients with spina bifida and latex sensitization

BACKGROUND: Some subjects with spina bifida (SB) and latex sensitization (cutaneous and/or serum IgE) can have clinical reactions, while others may have no symptoms after the exposure to latex products. OBJECTIVE: This study was carried out to determine the risk factors associated with latex allergy in patients affected with SB and latex sensitization. METHODS: Fifty-nine consecutive subjects affected with SB, besides answering a questionnaire, underwent a skin-prick test (SPT) to latex and the determination of the specific serum IgE (RAST CAP) to latex. The total serum IgE concentration was determined and SPT to common aero- and food-allergens, skin tests (prick + prick) with fresh foods (kiwi, pear, orange, pineapple, tomato, banana) and RAST CAP to the same foods tested by the prick + prick technique, were also performed. RESULTS: Fifteen out of the 59 subjects (25%) were sensitized to latex according to the presence of IgE to latex detected by SPT (nine patients) and/or RAST CAP (13 patients). Five out of the 15 sensitized patients (33%) suffered from clinical reactions to latex (urticaria, conjunctivitis, angioedema, rhinitis, bronchial asthma) while they were using latex gloves and while inflating latex balloons. In the 15 sensitized patients, the presence of specific latex seric IgE > 3.5 kU/L (>/= class 3), a positive latex SPT, an elevated total serum IgE, and a positive prick + prick and/or a positive RAST CAP to foods, were significant (P < 0.05) risk factors associated with latex symptoms. The other factors tested (age, gender, months of intermittent bladder catheterization, surgical procedures, SPT reactivity and clinical reactions to aero-allergens and food-allergens, skin tests for fresh foods, positive RAST CAP to foods) were not significantly different in symptomatic and asymptomatic patients. CONCLUSION: Significant risk factors for symptoms to latex in patients with SB and latex sensitization were a presence of specific IgE to latex > 3.5 kU/L, a more frequent positive latex SPT, elevated total IgE, and one or more positive prick + prick and/or RAST CAP to fresh foods.     

Latex allergy in spina bifida patients – prevention by primary prophylaxis

Background The effect of latex prophylaxis has not been investigated in spina bifida children, a high-risk group for latex allergy. As repeated operations have been identified as a major cause of latex sensitization, we wanted to find out whether primary latex prophylaxis during surgery could prevent latex allergy in children with spina bifida.
Methods In December 1995, we established latex-free surgery and anesthesia for all patients with spina bifida regardless of their sensitization to latex. Twelve children born after that date (mean age 1.2 years, mean ntmiber of operations 3.3, range 1 -7) were tested for specific IgE against latex until December 1997 (ImmunoCap, Pharmacia, Uppsala, Sweden) and compared with eight children born before December 1995 (mean age 1.3 years, mean number of operations 3.6, range 1–8), in whom a test for latex IgE had been done before the age of 2 years.
Results Before we established primary prophylaxis, three of seven children with spina bifida (38%) were sensitized to latex until the age of 2 years. After the establishment of a latex-free operating theater for spina bifida patients, none of the 12 patients were sensitized to latex despite up to seven operations in each child.
Conclusions Primary latex prophylaxis during surgery can prevent latex sensitization in young spina bifida patients.     

Detection of immunoglobulin antibodies in the sera of patients using purified latex allergens

BACKGROUND: Latex allergy is largely an occupational allergy due to sensitization to natural rubber latex allergens present in a number of health care and household products. Although several purified allergens are currently available for study, information on the usefulness of these purified, native or recombinant allergens in the demonstration of specific immunoglobulin (Ig) E in the sera of patients is lacking. OBJECTIVE: To evaluate the purified latex allergens and to demonstrate specific IgE antibody in the sera of health care workers and spina bifida patients with clinical latex allergy. METHODS: Two radioallergosorbent and an enzyme-linked immunosorbent assay (ELISA) using latex proteins Hev b 1, 2, 3, 4, 6 and 7 along with two glove extracts and Malaysian nonammoniated latex (MNA) were evaluated to demonstrate IgE in the sera of health care workers and spina bifida with latex allergy and controls with no history of latex allergy. RESULTS: ELISA using the purified latex allergens demonstrated specific IgE in 32-65% health care workers and 54-100% of spina bifida patients with latex allergy. The corresponding figures for RAST were 13-48 and 23-85 for RAST-1 and 19-61 and 36-57 for RAST-2. These results were comparable with the results obtained with glove extracts and crude rubber latex proteins. CONCLUSIONS: When used simultaneously, latex proteins Hev b 2 and Hev b 7 reacted significantly with specific serum IgE in 80% of health care workers and 92% of spina bifida patients with latex allergy by ELISA technique, while this combination gave lower positivity when the RASTs were used. By the addition of Hev b 3, specific IgE was detected in all spina bifida patients with latex allergy. Both RASTs failed to show specific IgE in the control subjects, while the ELISA showed significant latex-specific IgE in 22% of controls.     

Natural rubber latex allergy in children: a follow-up study.

BACKGROUND: Natural rubber latex (NRL) allergy occurs frequently in children with spina bifida and other children with disorders requiring multiple operations. Also atopic children who have not undergone surgery can be sensitized to NRL, but the outcome of these children has not been studied. OBJECTIVE: To study how NRL-allergic children manage at home and whether their skin prick test (SPT) reactivity, latex RAST or IgE antibody levels to NRL allergens change during the follow-up. METHODS: Twenty-four NRL-allergic children who had not undergone surgery and eight children with histories of multiple operations were followed up for a mean of 2.8 years. Clinical symptoms were recorded and all children were re-examined with SPT, latex RAST and ELISA for IgE antibodies to prohevein (Hev b 6.01), hevein (Hev b 6.02) and rubber elongation factor (REF, Hev b 1). RESULTS: Nineteen of the 24 NRL-allergic children (79%) who had not undergone surgery had occasionally contacts to balloons and other NRL products at home, and 10 of them experienced symptoms ranging from contact urticaria to systemic reactions. Three of the eight NRL-allergic children with a history of multiple operations had contacts to rubber balloons without any symptoms, and five children underwent 1-8 uneventful operations in a latex-free environment. SPT reactivity to NRL allergens, latex-RAST or IgE antibody levels to prohevein or hevein did not change in either group of NRL-allergic children during the follow-up. CONCLUSIONS: Occurrence of clinical symptoms and no decrease in SPT reactivity or IgE levels to NRL allergens in the course of the present follow-up study imply that more attention should be paid to the protection of NRL-allergic children from rubber contacts in the home environment.     

Determination of independent risk factors and comparative analysis of diagnostic methods for immediate type latex allergy in spina bifida patients

Background Development of allergy to natural rubber latex in spina bifida patients is determined by several risk factors, such as age, number of interventions and atopic disease that are, however, interdependent. Furthermore, several diagnostic procedures have been analysed, but a comprehensive analysis of their diagnostic significance is lacking. Objective To determine the independent major risk factor(s) for development of natural rubber latex allergy and the most valuable diagnostic procedure. Methods In aselectively collected spina bifida patients, we correlated existing natural rubber latex allergy with age, sex, atopy and the number of hospitalizations and of surgical interventions in appropriately matched subgroups. Allergy to natural rubber latex was established by application of a latex glove fragment on the skin. Skin-prick tests with glove eluate, a natural latex extract and a commercial latex extract were carried out as were specific IgE measurements by radioimmuno assay (RAST-CAP). The results of the latex application test are compared with the other diagnostic methods. Results Out of 74 fully evaluated patients, 17 had a positive application test. The number of surgical interventions correlates strongly with the presence of natural rubber latex allergy (P < 0.0002), independent of age, sex and presence of atopy. Skin-prick tests with unstandardized allergens made from known high allergenic latex gloves represent the most sensitive diagnostic method, with the highest negative predictive value and a specificity of 0.95. RAST-CAP was the next best method with a specificity of 0.93, a sensitivity of 0.89 and a negative predictive value of 0.97. Conclusion The number of surgical interventions is the major independent determining factor for allergy to natural rubber latex in spina bifida patients. Unstandardized skin-prick tests are the most sensitive and specific diagnostic tool, but RAST-CAP is almost equally performant and therefore a valid alternative.     

Natural rubber-latex allergy in patients not intensely exposed

Immediate-type allergy to natural rubber latex (NRL) is common in highly exposed groups, particularly in health-care workers and patients with spina bifida. The occurrence of NRL allergy was investigated in subjects not belonging to such risk groups. A total of 493 patients presenting with various diseases for allergologic evaluation was studied. A questionnaire-based history was taken, skin prick tests with NRL milk and common aeroallergens were done, and NRL-specific serum IgE antibodies were measured. A total of 317 subjects (64.3%) was atopic. There were skin prick test reactions to NRL in 80 (16.2%) and NRL-specific IgE in the serum in 79 (16.0%) subjects; both were found in 25 patients (5.1%). Altogether, NRL sensitization was found in 134 patients (27.2%). By history and/or challenge tests. 13 subjects (2.6%) were diagnosed as having clinically relevant NRL allergy. In five of these, anaphylactic reactions had occurred during dental procedures, and in four during general anesthesia; 10 subjects reported immediate-type reactions to NRL products in daily life. AU patients with clinically relevant NRL allergy had a skin prick test reaction to NRL milk (sensitivity 100%). Nine had specific IgE antibodies in the serum (sensitivity 69.2%); respective specificity was 86.0% or 85.4%. Nine of the 13 patients (69.2%) with NRL allergy were atopic. Despite exclusion of those at risk, many patients had clinically relevant allergy to NRL, and many of these had had severe reactions. NRL allergy is an important health issue also beyond the known risk groups.     

Latex allergy in children

Natural rubber is a component of the latex of the tropical Hevea brasiliensis tree which is widely used in the manufacturing of medical devices and a large variety of articles for everyday use. Over a dozen allergens have been identified in the latex of H. brasiliensis. The allergens Hev b 1, Hev b 3, Hev b 6, and Hev b 7 are proteins that are involved in the biosynthesis of rubber or the coagulation of latex. Allergens that are part of the plant's defense system are represented by Hev b 2 and class I endochitinases. The allergens Hev b 4, Hev b 5, and Hev b 8-10 were classified as either structural or housekeeping proteins. Immediate-type hypersensitivity reactions to proteins present in Hevea latex were first described in 1927. Since then, natural rubber latex (NRL) allergy has become an important medical problem for an increasing number of individuals. Sensitization mainly occurs by wound or mucosal contact with NRL devices during surgery or by inhalation of airborne allergens released from powdered latex gloves. The number of surgical interventions and an atopic disposition are the most important risk factors for developing latex allergy, especially in children with spina bifida. Exposure to NRL products should be carefully avoided for individuals who belong to high-risk groups. Initial studies on establishing a latex-free environment for surgery in all spina bifida patients have reported on a decrease in sensitization and allergy to NRL.     

Latex allergy within a cohort of not-at-risk subjects with respiratory symptoms: prevalence of latex sensitization and assessment of diagnostic tools

BACKGROUND: Immunoglobluin E (IgE)-mediated hypersensitivity to natural rubber latex (NRL) is a major problem in allergy practice. Currently, the use of skin prick tests (SPTs) with latex extracts and specific IgE detection for the diagnosis of NRL allergy in suspected patients is directed to identification of risk factors. Many cases of NRL allergy remain undiagnosed due to misreporting of symptoms by the patients or lack of proper questions asked by the physician. MATERIALS AND METHODS: A total of 6,126 subjects referred for respiratory symptoms underwent SPTs with NRL. Positive subjects were resurveyed for exposure to NRL, and specific IgE for NRL extracts and recombinant molecules was determined. Immunoblots of NRL extracts were performed to identify IgE patterns. RESULTS: Forty-six of 3,930 sensitized subjects had a positive SPT with NRL, displaying a prevalence of NRL sensitization of 0.75% for the general and 1.2% for the sensitized population. Eleven out of 46 (23.9%) subjects could be defined as NRL asymptomatic, whereas 35 (76.1%) developed symptoms upon exposure to NRL. Specific IgE to NRL was detected for 22 (75.86%) of 29 tested sera. Seventeen out of 22 (77%) sera displayed specific IgE to recombinant allergens with most reactions to Hev b 5, Hev b 6.01 and Hev b 6.02. Immunoblots of NRL extract fractions with patients' sera showed heterogeneous patterns. CONCLUSIONS: SPTs with NRL extract should be routinely performed in patients with respiratory symptoms. Hev b 5, Hev b 6.01 and Hev b 6.02 are the most important allergens, but further characterization of NRL extracts is needed to identify novel allergens and to clarify the role of crossreactive carbohydrate determinants.     

Latex allergy: a model for therapy

Allergy to natural rubber latex products emerged as an important clinical condition following an increase in the use of latex gloves for barrier protection in the early 1980s. In addition to latex glove users, other high‐risk groups with different latex exposure include spina bifida patients and others with multiple surgical procedures. Subjects with fruit and vegetable allergy are also at risk due to cross‐reactive allergens. Following the significant advances in the identification and characterization of common aeroallergens, latex allergy was well placed to become an excellent model of therapy. Awareness of latex allergy and modes of sensitization enabled epidemiological studies to inform allergen avoidance initiatives, substantially reducing inadvertent exposure in major hospitals in Western countries. Spina bifida is often identified in utero or soon after birth, allowing vigorous latex allergen avoidance with enhanced efficacy of primary prevention. However, changing demographics of latex allergy and technological revolution in countries such as China and India are predicted to unleash a second wave of latex allergy reemphasizing the incentive for improved manufacturing procedures for latex products. The desirable high tensile strength and elasticity of natural rubber latex have made the commercial identification of good alternatives very difficult but this would also be attractive for primary prevention. In addition, an effective specific immunotherapy regimen would be valuable for selected high‐risk atopic individuals. Current subcutaneous and sublingual immunotherapy schedules have been tested for treatment of latex allergy with evidence of efficacy but the risks of adverse events are high. For such potent allergens as latex, hypoallergenic but T cell‐reactive preparations are required for clinical use. Identification of allergenic components of latex products, with generation of monoclonal antibodies and recombinant allergens, allowed sequence determination and mapping of T cell and B cell epitopes. Together, these reagents and data facilitated improved diagnostics and investigation of novel‐specific therapeutics. Potential hypoallergenic latex preparations identified include modified non‐IgE‐reactive allergen molecules and short T cell epitope peptides. The co‐administration of adjunct therapies such as anti‐IgE or corticosteroids and of appropriate adjuvants for induction of regulatory T cell response offers promise for clinically effective, safe latex‐specific vaccines.     

Intraoperative anaphylaxis: an association with latex sensitivity

Latex products have recently been identified as the cause of severe intraoperative anaphylactic reactions. We have identified a group of pediatric patients who appear to be at increased risk for such reactions. Fifteen patients with either spina bifida or congenital urologic abnormalities experienced 19 intraoperative anaphylactic reactions. All patients had frequent previous exposures to rubber materials since infancy as part of their management and/or investigative procedures. Seven of 15 patients had a previous history of local skin reactions to rubber. Only four patients were atopic. All patients had undergone multiple (two of 26) operative procedures before their reactions, the onset of which ranged from 40 to 290 minutes after induction of anesthesia. The reactions varied in intensity from urticaria to severe cardiorespiratory collapse. All these patients subsequently had positive allergy skin tests and positive RAST to latex antigen. We conclude that this group is at risk when they are exposed to latex intraoperatively as a result of frequent past exposure to these materials. Allergic evaluation for latex allergy may assist in the preoperative evaluation of similar patients. In sensitized patients, appropriate prophylactic measures, particularly the avoidance of latex, is required.     

The search of latex sensitization in spina bifida: diagnostic approach

BACKGROUND: Sensitization to latex has become a major problem in children with spina bifida. Life-threatening reactions may occur in these patients, therefore the search of latex sensitization must be an active task in all of these children. OBJECTIVE: To design an approach for the diagnosis of latex sensitization in children with spina bifida. METHODS: We studied 100 consecutive unselected patients. Skin prick tests with a commercial latex extract were performed, latex-specific serum immunoglobulin (Ig) E was determined by CAP test, and risk factors were studied. Originally, patients with an area of latex skin test > 50% of the area of histamine and/or CAP class > or = 3 were considered sensitized to latex. Diagnostic tests were also performed in a control group of 51 atopic and nonatopic children. RESULTS: After performing a receiver-operating characteristics curve for both tests we recommend skin tests > 25% of the area of histamine (sensitivity - SEN = 79%, specificity - SPE = 100%, positive predictive value - PPV = 100%, negative predictive value - NPV = 90%), or CAP class > or = 2 (SEN = 88%, SPE = 100%, PPV = 100%, NPV = 94%) as diagnostic cut-off points. The anamnesis had a SEN of 44% for diagnosis, and a SPE of 100%. Latex sensitization was associated with more than 5 operations (OR = 8, 95% CI = 3-21.3), a personal history of atopy (OR = 11.5, 95% CI = 2.3-57.1), and serum total IgE > or = 2 z-units (OR = 4, 95% CI = 1. 6-10). CONCLUSION: For the routine evaluation of children with spina bifida, we propose a diagnostic algorithm with skin prick tests as a first step and CAP second.     

Latex sensitization in children with spina bifida: follow-up comparative study after two years.

BACKGROUND: Previous findings suggest that sensitization to latex in children with spina bifida is a dynamic process. OBJECTIVE: To study if changes appear in the sensitization status after withdrawal of latex. METHODS: We studied a consecutive sample of 68 children with spina bifida, by means of latex skin prick tests and quantification of serum latex-specific IgE on two separate occasions two years apart. RESULTS: Forty-four (65%) were classified as nonsensitized, 6 (9%) showed indeterminate results, and 18 (26%) were sensitized to latex, six of whom had clinical reactions to latex. They were instructed to avoid latex. In a second evaluation, 2 years later, 38 (56%) were classified as nonsensitized, 3 (4%) as indeterminate, and 27 (40%) as sensitized to latex, 11 of whom had presented latex symptoms. This meant 22% of spina bifida children demonstrated progressive sensitization, in spite of having adopted a latex-free environment at our hospital. It illustrates the progressive character of latex sensitization in these patients. CONCLUSION: Latex avoidance measures both in the medical and home settings must be stressed. We recommend that children with spina bifida should be periodically evaluated regarding latex sensitization.     

Latex hypersensitivity: personal data and review of the literature

Latex allergy is an increasingly common condition, because use of latex products is widespread. The reactions to latex manufactures can be classified as allergic and non-allergic, these are the most common. Latex proteins are responsible for immediate IgE-mediated hypersensitivity allergic reactions. Symptoms range from rhinitis, conjunctivitis and urticaria to anaphylactic shock. Chemical additives can cause allergic contact dermatitis. The clinical symptoms of latex allergy could arise from direct contact with latex products, but may also result from inhalation of airborne allergens. Subpopulations at particular risk include: atopics, children with spina bifida or individuals who required frequent surgical instrumentations, health care workers, and all persons who have regular contact with latex products. Diagnosis of allergy is based initially on history; search for specific serum IgE, skin prick test and provocation test may confirm the suspicion. The most effective strategy in the treatment of latex allergy is avoidance, however this is virtually impossible, given large number of latex products we encounter since childhood. In this paper we review the current state of knowledge concerning latex allergy, including the clinical spectrum, identified allergens, the cross-reactions regarding the latex-fruit syndrome, diagnostic procedures and preventive measures. Several personal data increase awareness on this issue.     

LATEX HYPERSENSITIVITY: PERSONAL DATA AND REVIEW OF THE LITERATURE

ABSTRACT

Latex allergy is an increasingly common condition, because use of latex products is widespread. The reactions to latex manufactures can be classified as allergic and non-allergic, these are the most common. Latex proteins are responsible for immediate IgE-mediated hypersensitivity allergic reactions. Symptoms range from rhinitis, conjunctivitis and urticaria to anaphylactic shock. Chemical additives can cause allergic contact dermatitis. The clinical symptoms of latex allergy could arise from direct contact with latex products, but may also result from inhalation of airborne allergens. Subpopulations at particular risk include: atopics, children with spina bifida or individuals who required frequent surgical instrumentations, health care workers, and all persons who have regular contact with latex products. Diagnosis of allergy is based initially on history; search for specific serum IgE, skin prick test and provocation test may confirm the suspicion. The most effective strategy in the treatment of latex allergy is avoidance, however this is virtually impossible, given large number of latex products we encounter since childhood. In this paper we review the current state of knowledge concerning latex allergy, including the clinical spectrum, identified allergens, the cross-reactions regarding the latex-fruit syndrome, diagnostic procedures and preventive measures. Several personal data increase awareness on this issue.     

Is there a role for immunoblots in the diagnosis of latex allergy? Intermethod comparison of in vitro and in vivo IgE assays in spina bifida patients

BACKGROUND: The best diagnostic method for latex allergy is still controversial. This investigation was designed to evaluate the diagnostic efficiency of immunoblotting in comparison with established in vitro and in vivo test systems. METHODS: A total of 108 spina bifida patients were investigated by questionnaire and skin prick test (SPT). Specific serum IgE to latex was analyzed by the Pharmacia CAP FEIA immunoassay, DPC AlaSTAT microplate immunoassay, and DPC AlaBLOT immunoblot. Patients were regarded as latex allergic if they reacted positively to challenge by the latex glove wearing test. RESULTS: Thirty-four patients reacted positively to challenge. The sensitivity rates were 97% (SPT), 94% (immunoblot, CAP), 74% (AlaSTAT), and 35% (clinical history). The specificity rates were 92% (clinical history), 88% (AlaSTAT), 77% (SPT), 76% (CAP), and 69% (immunoblot). If two methods were combined, efficiency rates were highest for SPT combined with CAP (sensitivity 94%, specificity 82%), with AlaSTAT (sensitivity 74%, specificity 92%), or with immunoblot (sensitivity 91%, specificity 84%). The sera of challenge-positive patients recognized more immunoblot bands than challenge-negative patients, and the severity of symptoms correlated with the number of recognized bands. CONCLUSIONS The diagnostic efficiency of immunoblotting is not superior to that of SPT. However, immunoblotting may serve as an additional tool to increase slightly the specificity of SPT and specific serum IgE tests.     

The prevalence of latex allergy in children seen in a university hospital allergy clinic

Natural rubber latex allergy is responsible for a wide spectrum of clinical symptoms, ranging from rhinoconjunctivitis to severe anaphylaxis, in both adults and children. An association between allergy to latex and allergy to various fruits has been reported. This study investigated the prevalence and clinical significance of latex sensitization in children seen in a university hospital allergy clinic. A total of 453 consecutive children were screened in a 7-month period. A detailed clinical history with particular attention to the past surgical history and the eventual presence of latex- or food-induced allergic symptoms was obtained. Skin prick tests (SPT) for the more important inhalant allergens and foods were performed on all children. In patients with positive latex SPT, latex challenge and additional SPT for some fresh foods (avocado, pineapple, apricot, grape, banana, pear, apple, orange, almond, and chestnut) were also performed. RAST for the same food antigens, as well as patch test with latex and a standard battery of contact allergens, was also done. Of 326 atopic children, 10 (3%) presented positive skin test to latex, but only five (1.5%) also had a positive clinical history to latex exposure. Latex challenge was positive in 3/9 positive-latex-SPT children. None of the nonatopic children had positive skin test to latex or symptoms to latex exposure. A history of previous surgery was found in 5/10 positive-latex-SPT children, in 63/316 negative-latex-SPT atopic children (P<0.05), and in 23/127 nonatopic children. RAST to latex was positive in 5/10 positive-latex-SPT children. Associated fruit-specific IgE (SPT and/or RAST) were found in all latex-symptomatic children and in 2/5 latex-asymptomatic children. Apple, kiwi, and chestnut were the most common SPT-positive foods. Only one patient with clinical allergy to latex and positive skin tests to fruits had a history of clinical symptoms after ingestion of kiwi and orange. The natural history of the positive-latex-SPT children without clinical reactions to latex exposure and the clinical significance of the association of latex and fruit sensitivity require further studies.     

Latex allergy in fruit-allergic patients

The purpose of this study was to investigate the prevalence of latex allergy in fruit-allergic patients, and to assess its clinical significance. Fifty-seven fruit-allergic patients and 50 non-fruit-allergic atopic patient controls were studied. All patients were questioned about conventional immediate symptoms after contact with latex products. Patients also underwent skin prick testing and determination of specific serum IgE to latex, as well as a screening test for environmental allergens. Immunologic latex sensitization occurred in 49/57 (85.9%) fruit-allergic patients, who showed a positive STP and/or CAP to latex, but in only two controls ( P <0.001). Six out of 57 (10.5%) fruit-allergic patients suffered from clinically relevant latex allergy. Symptoms included contact urticaria, angioedema, conjunctivitis, generalized urticaria, and moderate anaphylactic reactions. No control reported symptoms with latex products ( P =0.052). In all patients, clinical symptoms to fruits preceded a history of latex allergy. The fruits most associated were melon, peach, and banana. From our data, we conclude that there is a potential for allergic reactions to latex in patients with allergy to fruit. All patients with fruit allergy should be screened for individual risk of latex allergy.     

Serum reactivities to latex proteins (Hevea brasiliensis)

Background: In recent years there has been an increasing incidence of allergy to latex among health care workers and children with spina bifida. The allergic response in these individuals can be severe and occasionally fatal. Several allergens have been identified with the use of sera from different patient groups. In our effort to identify reagents for in vitro testing and clinical use, we investigated the reactivities of latex proteins to sera collected from a wide range of patients with latex allergy. Methods: Twenty-six serum samples were obtained from adult patients with latex allergy, both hospital workers and non-hospital workers. Serum pools were made either from sera of children with spina bifida or sera of adult patients with latex allergy. Proteins from C-serum and latex particles of latex sap (nonammoniated) were separated by different gel electrophoresis techniques and evaluated for specific IgE binding by immunoblotting. Results: More than 50% of the sera tested reacted to an 18 kd protein, a 25.6 kd acidic protein with an isoelectric point of 3.5, or to both proteins; whereas only 23% of the individual serum samples tested reacted to the rubber elongation factor, which has been reported to be a major latex allergen. The immunoreactive patterns of children's and adults' serum pools were similar but not identical. Conclusions: With the use of gel electrophoresis and immunoblotting techniques, different immunoreactive proteins were identified in C-serum and particles of latex. Rubber elongation factor, which reacted to only 23% of sera tested, did not appear to cross-react immunologically with other latex allergens. (J ALLERGY CLIN IMMUNOL 1995;95:1196-1205.)     

Unique and shared IgE epitopes of Hev b 1 and Hev b 3 in latex allergy

Of the several latex proteins cloned and expressed, the rubber elongation factor, Hev b 1, and the closely related Hev b 3, represent two major allergens associated with latex allergy. Although both allergens demonstrated IgE binding with sera from latex allergic patients, it was not known whether these two molecules shared any epitopes. Hence, in the present study using health care workers (HCW) and spina bifida (SB) patients with latex allergy, we investigated the IgE binding epitopes in Hev b 1 and Hev b 3. Recombinant Hev b 1 and Hev b 3 were expressed in a prokaryotic expression system, while overlapping decapeptides of Hev b 1 and Hev b 3 were synthesized on derivatized cellulose membrane. Eight IgE binding epitopes for Hev b 1 and eleven for Hev b 3 were identified using sera from latex allergic patients with SB. On further analysis of synthetic peptides encompassing these epitopes, similar IgE antibody reactivity was demonstrated with three Hev b 1 epitopes b1E3, b1E5, b1E6 and two Hev b 3 epitopes; b3E10 and b3E 11. For Hev b 1, a unique IgE binding epitope was identified in the region of amino acid residues 16-25. In competitive ELISA, peptides bIE2 and bIE4 together inhibited 58% of IgE binding of Hev b 1, while b3E5 showed 22% inhibition in the IgE binding of Hev b 3. The results of the present study suggest that the understanding of linear and conformational IgE epitopes in the major latex allergens may provide better insight into the structure-function relationship of the allergens, and may lead to the development of better patient care and management strategies in latex allergy.     

Latex allergy: allergen identification in Hevea braziliensis fractions by immunoblotting

Background Latex is the cause of several clinical symptoms of allergy, but the identification of allergens is not completely known. Objective The aim of this report was to study the immunoreactivity of puritied stable latex fractions from Hevea braziliensis. Methods We purified the cytoplasm of Hevea braziliensis and obtained three fractions: latex particles (LP), lutoids (L) and cytosolic serum (CS). Using Western blot, specific IgE directed to latex allergens was found in 80 patients with latex allergy. Results Five major groups of allergens migrating as 14, 25, 29, 37–45 and 50kDa were recognized. They were unequally distributed within the latex fractions: 37–45 kDa proteins were essentially recognized in CS and LP, whereas 14 and 29 kDa proteins were mainly labelled in the L fraction. As a control, aqueous glove extracts exhibited a more restricted pattern of reactivity, because only 14 and 29 kDa proteins were recognized by patient sera. The pattern of reactivity was not correlated with specific IgE levels, but sera from patients suffering from spina bifida reacted specifically with the minor protein of 25 kDa located in LP. Conclusions The present results show that latex allergic patients recognize several allergens which are differently distributed in subcellular fractions extracted from H. braziliensis and aqueous GE. The L fraction and GE were enriched in low molecular weight proteins and apparently contained the same allergens.