Latex-specific IgE Antibodies Research Articles

Diagnostic performance of Food and Drug Administration–cleared serologic assays for natural rubber latex–specific IgE antibody

Background: In the absence of Food and Drug Administration–approved natural rubber latex skin testing reagents, latex-specific IgE antibody immunoassays are used in the diagnosis of latex allergy. Comparative diagnostic performance of these tests has not been definitively determined. Objective: We sought to study the predictive value of available Food and Drug Administration (510K)–cleared latex-specific IgE antibody immunoassays in the diagnosis of latex allergy. Methods: Subjects (n = 312) were classified as having a positive (n = 117) or a negative (n = 195) latex allergy history (Hx) or having a positive (n = 131) or a negative (n = 181) puncture skin test (PST) response (Greer reagent). The 14 subjects with a negative Hx and a positive PST response had negative responses to glove provocation testing and thus were considered sensitized but asymptomatic. Sera from 22 subjects were split to evaluate intra-assay variation. All 334 coded sera were analyzed for latex-specific IgE antibodies in the Diagnostic Products Corporation microplate AlaSTAT, Hycor HY-TEC EIA System, and Pharmacia-UpJohn CAP System. Variance and diagnostic performance parameters of each test were computed with 95% confidence intervals in relation to the subjects’ Hx and PST status. Results: Intra-assay concordance of split sera results was 96.0% for all 3 assays, with coefficients of variation of less than 25% and between-assay coefficients of variation of less than 21%. The diagnostic performance of the CAP and AlaSTAT assays were equivalent in comparison with PST results: sensitivity, CAP 76.3% and ALASTAT 73.3% and specificity, CAP 96.7% and AlaSTAT 97.2% ( P = NS). The HY-TEC assay was more sensitive (91.6%) and less specific (73.3%) than the CAP and AlaSTAT assays ( P < .001). From 9% to 25% of the sera were discordant, being positive in at least 1, but not all 3, assays. Conclusion: The CAP and AlaSTAT assays produce 24% and 27% of false-negative results, respectively, whereas the HY-TEC produces 27% of false-positive results when compared with the PST. (J Allergy Clin Immunol 1999;103:925-30.)

Latex sensitization in spina bifida appears disease-associated

Objective: The high prevalence of latex sensitization (up to 80%) in patients with spina bifida (SB) has been attributed to repeated exposure to latex products, whereas disease-associated factors have not been considered. Methods: We compared children with SB (n = 21) and children with posthemorrhagic or congenital hydrocephalus (PH, n = 32), all of whom had a ventriculoperitoneal shunt since young age. Latex sensitization, number of operations, atopic history, and total IgE levels were evaluated. Results: The following characteristics were recorded: age (SB: 52 months, range 1 to 264 months; PH: 71 months, range 1 to 192 months) and mean number of operations (SB: 2.09; PH: 2.53). Of the SB group, 43% (9 of 21) showed elevated latex-specific IgE antibodies in contrast to 6% (2 of 32) in the PH group ( P < .01). Latex-specific IgE antibodies were detected by 1 year of age, and one surgical operation was sufficient to induce latex-specific IgE-antibody production in patients with SB. Conclusions: The results suggest that the SB population bears a disease-associated propensity for latex sensitization. Sensitization to latex antigens may occur after the very first contact, arguing for latex avoidance measures from the very beginning of life. (J Pediatr 1999;134:344-8)

Latex sensitization: occupational versus general population prevalence rates.

Natural rubber latex (NRL) has become an important occupational health concern in recent years, particularly among health care workers. It has been suggested in some reports that the prevalence of latex sensitization among occupationally exposed groups is not different from that in the general population. The findings of prevalence studies conducted among occupationally-exposed and general population groups were reviewed to determine whether there is evidence to support this suggestion. Numerous surveys of HCWs have demonstrated that the prevalence of sensitization to latex ranged in most studies from 5 to 12%; sensitization of HCWs may produce clinical effects including urticaria, rhinoconjunctivitis, occupational asthma, and potentially life-threatening anaphylactic shock. More than a decade ago, data from Finland indicated that the prevalence of latex allergy in the general population was less than 1%. Recent reports from Finland have confirmed this, with observations that 0.7-1.1% of large series of patients were NRL-allergic, while among 804 unselected patients, the prevalence of latex skin prick test (SPT) positivity was 0.12%. In contrast, other studies have suggested that from 4 to 6.4% of individuals tested were positive for serum latex-specific IgE antibodies. However, the specificity of these assays has been reported to be low. In three recent studies based on SPTs, published in 1997, the prevalence of positive reactions to latex was about 1% or less. The prevalence was 0.7% (95% CI 0.3-1.4) among 758 apprentices in Quebec, Canada; and 1.1% among more than 3,000 children tested in Finland (1.0% confirmed on latex use test). There were no first- and second-year dental students with positive latex SPTs in Ontario, Canada. These recent investigations provide further evidence consistent with earlier studies based on skin testing that the prevalence of latex sensitization in occupationally-unexposed groups is quite low (< 1%). The marked differences in the findings based on serological assays may relate to the nonspecificity of these assays and deserve further investigation.

The Prevalence of Latex-Specific IgE Antibodies Among Pediatric Patients in a Chronic Care Facility

We conducted a study to determine the prevalence of natural rubber latex (latex) hypersensitivity among children living in a chronic care facility and to assess symptoms and demographic and medical risk factors for latex hypersensitivity. A cross-sectional descriptive study was conducted on a population of 50 children with complex medical problems living in a chronic care facility. Latex hypersensitivity was determined by radioallergosorbent assay (RAST). Demographic and medical history data were collected from the medical chart. Twelve (24%) of the children in the cohort tested positive for latex-specific IgE antibodies. Six (50%) had a history of urticaria and all 12 had a history of wheezing. Both symptoms were significantly associated with the presence of latex-specific IgE antibodies by statistical analysis. In chi-square analyses, male sex and presence of a ventriculoperitoneal (VP) shunt were significantly associated with latex hypersensitivity. Adjusted for covariates, the presence of a VP shunt i...

Reduction of latex aeroallergens and latex-specific IgE antibodies in sensitized workers after removal of powdered natural rubber latex gloves in a hospital

Background: Respiratory symptoms of natural rubber latex (NRL) allergy in health care workers (HCWs) have been reported in rooms with a detectable allergen load. Preventive measures have been proposed to reduce the risk of NRL sensitization. Objectives: Eliminating powdered NRL gloves from the workplace and giving NRL-free material to sensitized workers has been among proposed preventive measures. To appraise the success of such procedures among HCWs, a prospective study was carried out. Methods: Sensitization of HCWs to NRL was determined by skin prick tests and measurements of specific IgE antibodies. NRL allergen concentrations in room air were measured before and after substitution of powdered NRL gloves with powder-free or synthetic gloves in different departments of a hospital and determined by a competitive inhibition immunoassay. Results: The prevalence of HCWs with positive skin prick test responses and NRL-specific IgE-positive HCWs was 8% (n = 7) among the 90 examined staff members before the intervention started. All 7 reported glove-related allergic symptoms. Six of 7 sensitized subjects had a significant decrease of latex-specific IgE antibody concentrations during follow-up examinations in April and September 1997 ( P < .003). Within 24 hours after substitution took place, NRL aeroallergen levels (up to 49.9 ng/m 3 ) fell below the detection limit in areas with synthetic gloves or powder-free NRL gloves alike. Use of asthma medication and antiallergic drugs could be discontinued by 2 HCWs with NRL-related respiratory tract symptoms. Conclusions: Our results demonstrate that elimination of powdered NRL gloves is a useful device in reducing aerogen NRL allergen loads below the detection limit and permitting sensitized or allergic personnel to remain on the job. (J Allergy Clin Immunol 1998;102:841-6.)

Can a threshold limit value for natural rubber latex airborne allergens be defined?

Background: Recent studies have shown that systemic or respiratory occupational responses to latex can be induced by inhalation of latex aeroallergens. Objective: Our objectives were to study the relationship between exposure to different latex aeroallergen levels and type I allergic reactions in subjects with occupational contact with latex and to assess a threshold value for latex airborne allergens required for sensitization and symptom elicitation. Methods: We screened 145 subjects working in 32 hospitals or operating rooms with different latex aeroallergen levels. The quantified latex aeroallergen concentrations in the 32 rooms were compared with latex-related allergic symptoms. Results: Different latex aeroallergen concentrations could be detected in rooms where powdered latex gloves were used and no effective ventilation systems were installed. In environments with latex aeroallergen levels of 0.6 ng/m 3 or greater, the reported workplace-related symptoms were significantly increased ( p < 0.02). All 22 subjects with latex-specific IgE antibodies worked in rooms contaminated with latex aeroallergens ( p < 0.05). Conclusions: Our results demonstrate that symptoms and presence of latex-specific IgE antibodies in subjects are significantly associated with measurable levels of latex aeroallergens. A latex aeroallergen level of 0.6 ng/m 3 is a critical threshold, especially for health care workers who are sensitized to natural rubber latex.(J Allergy Clin Immunol 1998;101:24-7.)

Prevalence of latex-specific IgE antibodies in hospital personnel

Prevalence of latex-specific IgE antibodies in hospital personnel

Prevalence of Latex-specific IgE Antibodies in Hospital Personnel

Prevalence of Latex-specific IgE Antibodies in Hospital Personnel

Prevalence of Latex-specific IgE Antibodies in Hospital Personnel

Prevalence of Latex-specific IgE Antibodies in Hospital Personnel

Prevalence of latex-specific IgE antibodies in atopic and nonatopic children with type I diabetes.

The potential induction of allergic sensitization to latex from insulin vial tops stimulated an investigation of the prevalence of specific IgE antibodies to latex in serum and the relationship to atopic disease in children with diabetes. In a cross-sectional study, serum samples of 112 children with type I diabetes (age: 15 [5-18] years; diabetes duration: 6 [1-14] years; median [range]) were investigated for total IgE, IgE screening for inhalational and nutritional allergens, and specific IgE antibodies to latex. Specific IgE antibodies for inhalational and/or nutritional allergens was found in 42 (38%) children (atopic group). Seven children (6%) exhibited specific IgE antibodies (0.61 [0.40-3.84] kU/I) to latex in serum although none reported clinical symptoms of latex allergy. All latex-sensitized children were found in the atopic group. This prevalence of latex sensitization of 17% (7/42) in atopic children with diabetes is comparable with the frequency described in atopic children without diabetes. These seven patients had higher serum total IgE antibody levels (328 [113-1,000] kU/I) than atopic patients without latex sensitization (n = 35; 124 [24-857] kU/I; P < 0.05) or patients without atopy (n = 70; 33 [2-339] kU/I; P < 0.001). No differences in age or diabetes duration were observed between either group. Sensitization to latex is found exclusively in children with atopic sensitization and appears to be related to atopic disease and not to frequent contact to latex through insulin injections. However, atopic patients may be at risk for reactions secondary to latex from insulin vials and syringes.

GROWTH HORMONE TREATMENT IN A CHILD WITH LATEX ALLERGY AND MYELOMENINGOCELE.50

Latex allergy is recognized with increasing frequency in children with myelomeningocele. A 5 year old female child with a documented history of latex allergy and myelomeningocele was evaluated for poor growth. The patient had a history of rashes/urticaria and one episode of wheezing upon exposure to products made of natural rubber latex. Following an endocrinologic evaluation growth hormone (GH) therapy was planned. GH is routinely dispensed in powdered form in a glass vial with rubber stopper and administered by insulin syringe. The stopper is entered by syringe multiple times (once when the diluent is added and then daily to withdraw the GH for injection), potentially releasing latex particles into the solution, which could be injected into the patient along with the GH. Prior to initiating GH therapy the patient had a positive latex-specific IgE antibody test =7.1 ng/ml (> than 2.0 ng/ml indicates a high propensity for developing an allergic reaction). Because of concern of anaphylaxis, the patient was admitted to the hospital for prick and intradermal skin testing with the prepared GH solution. In order to more closely mimic home administration of GH, the diluent was added 7 days prior to use. The vial was stored inverted (to maximize contact with the rubber stopper) and the rubber stopper entered several times with a needle. The patient's response to this solution of GH (0.74 mg= daily dose) was equal to that of the negative control (saline) while demonstrating an adequate response to the positive control (histamine). The patient has been treated with GH (0.3 mg/kg/week) for a total of 9 months without any adverse reactions. Despite an increase in the latex-specific IgE antibody test to 11.1 ng/ml one month after the initiation of GH therapy, she has never experienced any local nor systemic reactions to the GH and continues on this current therapy. The development of latex allergy in children with myelomeningocele is of increasing concern. Latex allergy should not preclude treatment with GH. With appropriate measures, children with latex sensitivity may be treated with GH without adverse reaction.

Comparative Studies of Latex Extracts Used in Skin Testing

There has been considerable variability reported in latex extracts used for skin testing and the results of those skin tests in the evaluation of latex allergy. Some test extracts have been associated with the induction of anaphylactic reactions in sensitive patients, while others have been reported as without adverse reactions. The present study was designed to evaluate late extracts by comparing antigens from latex gloves. Latex gloves were extracted for from 15 minutes to 24 hours for their protein contents and in vitro reactivities with IgE antibodies using sera of latex allergic patients and controls by ELISA. A higher yield of proteins was obtained after prolonged extraction, although reactivity of the sera by ELISA showed no major differences among the extracts. Extracts of 15 minutes elicited stronger reaction with health care workers and patients with spina bifida than with 24-hour extracts. The 15-minute extract demonstrated comparatively more reactive antigenic components in the fractions representing 3 to 10 and 10 to 30-kDa compared with fractions having less than 3 and over 30-kDa antigens. The study provided no evidence regarding the safety of one latex extract over the other related to time of extraction. The results indicated that a 15-minute extract can be used in ELISA for in vitro and, as in the literature, safe in vivo demonstration of latex specific IgE antibody.

Relevance of latex aeroallergen for healthcare workers

ABSTRACT The dispersion of latex allergen bound on glove powder has been shown to be of clinical importance to latex-sensitized medical staff and patients. To investigate whether latex aeroallergen is associated with the development of latex allergic reactions in health care workers, air samples were collected in 33 hospital rooms and two physicians' offices. Concentrations of latex allergens in the samples were determined by a competitive inhibition immunoassay and related to reported hypersensitivity reactions and to specific IgE results of 111 staff members engaged in these rooms. Latex aeroallergen (up to 205 ng/m 3 ) could be detected in all rooms where powdered latex gloves were used and ventilation systems were not installed. Conjunctivitis ( n =10), rhinitis ( n =12) and dyspnea ( n =4) were reported exclusively by employees working in such contaminated rooms. Also workers with latex-specific IgE antibodies ( n =l 7) were found only in these rooms. Urticaria in personnel ( n =26) was reported in rooms with and without detectable allergen load. All symptoms were significantly associated with latex-specific IgE antibodies. Our results demonstrate that immediate-type sensitization and allergic symptoms are associated with detectable latex aeroallergen.

Prevalence of Latex-Specific IgE Antibodies in Hospital Personnel

Rubber latex hypersensitivity is an important concern for health care workers. The Center for Devices and Radiological Health, in collaboration with the Consumer Product Safety Commission, conducted a multicenter study of the prevalence of latex-specific IgE antibodies among United States hospital personnel. Nine hospitals participated in the cross-sectional study. A total of 504 hospital personnel completed questionnaires that provided an array of demographic, occupational, and clinical information, including a history, if any, of allergies and the use of latex and nonlatex gloves. More than three-quarters (76.5%) of the participants were tested for total IgE and latex specific IgE. A total of 21 (5.5%, 95% CI = 3%-7%) of the tested participants were positive for the presence of latex specific IgE antibodies, defined as a latex IgE level of > or = 0.6 ng/mL. Latex specific IgE antibodies were more prevalent in participants who reported tachycardia, palpitations, flushing, or wheezing associated with latex gloves (Odds Ratio = 10.2, 95% CI = 3.7-28.6). The study's results suggest that the prevalence of latex-specific IgE antibodies among hospital personnel is appreciable and these personnel and their health care providers should be aware of this entity.

Diagnosis of natural rubber latex allergy

The accurate diagnosis of a latex-allergic individual begins with a comprehensive clinical history. Atopy, food allergies, hand dermatitis, and temporal relationships between allergic symptoms and natural rubber product exposure are risk factors that increase the suspicion of latex allergy. If symptoms are temporally delayed (hours-days) and confined to skin-latex product contact areas, Type IV hypersensitivity should be suspected and patch testing may be performed to identify activated T cells that are specific for selected rubber chemical additives. If ocular, upper and lower airway, and/or systemic allergic symptoms are observed with rapid onset (minutes) following a definable latex exposure, Type I hypersensitivity should be suspected. One or several confirmatory tests for latex-specific IgE antibody in the skin or blood may next be performed to verify a sensitized (IgE antibody positive) state. If the clinical history remains discordant with a skin test or blood test result, in vivo provocation tests may be cautiously considered for adjudication. Diagnostic methods for latex-specific IgE antibody detection in skin and blood are overviewed, with a focus on their performance, advantages, and limitations.

Shared IgE-binding sites among separated components of natural rubber latex.

IgE-mediated allergy to proteins present in natural rubber latex is a well-recognized problem. Latex contains a complex mixture of proteins ranging in molecular weight from 6 to > 200 kD. The aim of this study was to determine whether shared allergenic sites exist on separate latex components. Following electrophoresis, latex components at 14, 24, and 46 kD were electroeluted from SDS-polyacrylamide gels and used in ELISA inhibition and immunoblot inhibition studies of human latex-specific IgE antibodies. A minimum of 4 major allergenic sites (for convenience labeled A through D) were found to exist in 3 components of nonammoniated latex. Minimally, 2 are present in the 14-kD component (A, B) and 3 in the 24-kD component (A-C). The 46-kD fraction has 3 or more antigenic sites (A, C, D) but lacks one (B) that is present in both the 14- and 24-kD components. Four different IgE-binding moieties were detected among three latex protein components (14, 24 and 46 kD). Some of these allergenic sites were shared by two or more components. Recovery of these and others from fragmented latex components will allow identification of their amino acid composition and their availability will ultimately lead to better diagnostic and therapeutic options for patients with latex allergy.

An Epidemic of Occupational Allergy to Latex Involving Health Care Workers

IgE-mediated sensitivity to natural rubber latex is being recognized more frequently among health care workers. Between January 1990 and June 1993, we evaluated 342 consecutive Mayo Medical Center employees who reported symptoms suggestive of latex allergy. All were interviewed and underwent puncture skin testing with extracts of rubber gloves. In some cases, latex-specific IgE antibodies were measured by immunoassay. One hundred four of the 342 employees evaluated (30%) were latex-allergic. Risk factors for sensitization included frequent use of disposable gloves, presence of prior atopic disease, and prior or current hand dermatitis. The peak onset of symptoms occurred in late 1989 and early 1990 and did not correlate with a peak in glove usage at our medical center, which continued to rise. Most sensitized employees (78%) reported contact urticaria from rubber gloves, and over two thirds also experienced allergic rhinitis, conjunctivitis, or asthma when working in areas where large numbers of gloves were being used. Sixteen episodes of rubber-induced anaphylaxis were documented in 12 employees; six episodes occurred after latex skin testing and were easily reversed with appropriate therapy. Our findings substantiate a local epidemic of latex allergy among medical center employees. Epidemiologic studies are needed to assess the effects of various interventions to reduce occupational exposure to latex allergens. Although prick skin testing with concentrated latex glove extracts presents some risk of systemic reaction, pending availability of commercial diagnostic extracts, such testing is generally safe when performed by skilled laboratory personnel. Skin testing is warranted to investigate health care workers suspected of being latex-sensitive.

Comparison of latex hypersensitivity among patients with neurologic defects

Background: Latex hypersensitivity has been described in discrete populations including health care workers and children with spina bifida (SB). Objective: This study was designed to determine whether the SB population is a unique neuroimmunologic group manifesting this sensitivity. Methods: Four groups of subjects were studied. These included: 36 patients with SB with or without clinical evidence of latex hypersensitivity, 50 patients with spinal cord injury (SCI), and 10 patients with cerebrovascular accidents (CVAs), all of whom were questioned regarding contact with and possible clinical allergic reactions to latex. Ten healthy control subjects were also studied. We used a latex sap extract, previously shown to react with latex-specific IgE in a biotin-avidin ELISA, to determine latex-specific IgE antibody titers and to compare the groups. Results: Responses to questionnaires indicated that neither the patients with SCI nor the patients with CVA had histories suggestive of latex hypersensitivity. In contrast, 72% of the SB population had histories of clinical latex allergy. Comparisons of latex contact among the SB, SCI, CVA, and control groups revealed that the SB and SCI groups had similar latex exposure, whereas the other groups had less exposure. Both the SB and SCI groups had an average of two surgical procedures per year, which was greater than the average for the other groups. Comparisons of IgE latex antibody titers among the groups indicated that only the SB group had significant levels. The mean optical density values for each group were: 0.299 ± 0.177 for patients with SB and positive skin prick test results, 0.072 ± 0.066 for patients with SB and negative skin prick test results, 0.098 ± 0.005 in patients with SCI, 0.073 ± 0.038 in patients with CVA, and 0.053 ± 0.034 in control subjects. The percentages of positive latex IgE antibody detection were 72% for SB, 4% for SCI, 0% for CVA, and 0% for control groups. Conclusions: The results suggest that the SB population is unique in demonstrating IgE responses to latex contact, which may be due to increased latex exposure or altered neuroimmunologic interactions. (J A LLERGY C LIN I MMUNOL 1995;95:950-4.)

Immunoglobulin E reactivity to latex antigens in the sera of patients from Finland and the United States

Background: Patients with latex sensitivity and latex antigens from the United States and Finland, two countries where allergic reactions to latex have been widely reported, were evaluated to determine the spectrum of immune responses. Methods: Sera from 27 patients from Finland and 18 from the United States with latex allergy and control sera from nonsensitive individuals were studied for latex-specific IgE antibodies. Four antigen preparations were used: two extracted from gloves and one each extracted from rubber tree sap from Malaysia and India. All 45 patients had skin prick test results that were positive to latex antigens, and all sera were evaluated by enzyme-linked immunosorbent assay (ELISA) with the various antigens. Results: There were considerable differences in the reactivity of patient sera with the different antigens. Only 50% of the sera from patients with latex allergy from Finland demonstrated significant levels of IgE to latex as determined by enzyme-linked immunosorbent assay. These patients showed more reactivity with rubber tree sap antigens than with glove antigens. However, 72% of the patients from the United States demonstrated antibodies to latex, and no marked differences were noted between the antigen extracts. Conclusions: The results indicate that reagents such as rubber tree sap, which contain multiple clinically significant antigenic components, should be included in evaluation of latex allergy and that differences in patient populations may result in serologic variances.

Incidence of Latex Allergy in Atopic Children and Hospital Workers in Japan

The incidence of latex-induced allergy has been reported to be increasing in Europe and the US but not in Japan. We thus measured latex-specific IgE antibodies and latex-specific IgG antibodies in sera from 196 atopic children with low serum IgE levels (under 1,000 U/ml; group 1), 108 atopic children with high serum IgE levels (over 1,000 U/ml; group 2) and 601 hospital employees (group 3). Atopic children were diagnosed as having asthma, atopic dermatitis and/or food intolerance. One out of group 1 (0.5%) and 11 out of group 2 (10.2%) were found to have latex-specific IgE by radioallergosorbent assay (RAST), and 7 were further found to be positive for latex antigen by skin test. Fifty-five percent of group 1, 65% of group 2 and 9.7% of group 3 were found to have latex-specific IgG over 100 units/ml by enzyme linked immunosorbent assay (ELISA). Prior to our diagnosis most of the children and employees did not realize they were allergic to latex. These data suggest that caution should be taken regarding latex allergy when atopic children have to be operated upon as atopic children tend to be sensitized to the latex antigen after even minimal contact with latex products.