Latex allergy: past and present

Opportunities and obstacles in translating evidence to policy in occupational asthma

PURPOSE

Occupational asthma (OA), a common respiratory disorder in Western countries, is caused by exposures at the workplace. It is part of a broader definition of work-related asthma (WRA) that also includes pre-existing asthma aggravated by substances present in the workplace environment, and it is potentially preventable. The purpose of this paper is to illustrate preventive measures for occupational asthma by case studies.

METHODS

In three case studies we discuss preventive measures that have been associated with reductions in incidence of occupational asthma from natural rubber latex and from diisocyanates as supported by published literature. We also discuss challenges in relation to asthma from cleaning products in healthcare work.

RESULTS AND CONCLUSIONS

Several preventive measures have been associated with reduction in incidence of occupational asthma from natural rubber latex and from diisocyanates, and may provide lessons for prevention of other causes of occupational asthma. Cleaning products remain an unresolved problem at present with respect to asthma risks but potential measures include the use of safer products and safer applications such as avoidance of spray products, use of occupational hygiene methods such as improving local ventilation, and when appropriate, the use of personal protective devices.

Identification and practical management of latex allergy in occupational settings

Allergy to natural rubber latex (NRL) from Hevea brasiliensis is a relevant occupational health hazard. The use of gloves and products manufactured with latex and environmental allergen exposure in the work environment are risks factors for the development of occupational allergy among different job categories. Healthcare workers have been the most commonly affected, but other professions with exposure to latex products such as hairdressers, cleaners, food handlers and those making natural rubber latex (NRL) products are also at risk of developing occupational allergy. Clinical manifestations of IgE-mediated latex allergy can range from troublesome skin disorders to life-threatening systemic reactions. It is very important to identify the occupational allergic diseases in their early stages in order to implement avoidance strategies. For this purpose, the interventions for prevention should emphasize the importance of latex allergy awareness and surveillance among exposed workforces.

Impact of the phlebotomy training based on CLSI/NCCLS H03-a6 - procedures for the collection of diagnostic blood specimens by venipuncture

Introduction:

The activities involving phlebotomy, a critical task for obtaining diagnostic blood samples, are poorly studied as regards the major sources of errors and the procedures related to laboratory quality control. The aim of this study was to verify the compliance with CLSI documents of clinical laboratories from South America and to assess whether teaching phlebotomists to follow the exact procedure for blood collection by venipuncture from CLSI/NCCLS H03-A6 - Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture might improve the quality of the process.

Materials and methods:

A survey was sent by mail to 3674 laboratories from South America to verify the use of CLSI documents. Thirty skilled phlebotomists were trained with the CLSI H03-A6 document to perform venipuncture procedures for a period of 20 consecutive working days. The overall performances of the phlebotomists were further compared before and after the training program.

Results:

2622 from 2781 laboratories that did answer our survey used CLSI documents to standardize their procedures and process. The phlebotomists’ training for 20 days before our evaluation completely eliminated non-conformity procedures for: i) incorrect friction of the forearm, during the cleaning of the venipuncture site to ease vein location; ii) incorrect sequence of vacuum tubes collection; and iii) inadequate mixing of the blood in primary vacuum tubes containing anticoagulants or clot activators. Unfortunately the CLSI H03-A6 document does not caution against both unsuitable tourniquet application time (i.e., for more than one minute) and inappropriate request to clench the fist repeatedly. These inadequate procedures were observed for all phlebotomists.

Conclusion:

We showed that strict observance of the CLSI H03-A6 document can remarkably improve quality, although the various steps for collecting diagnostic blood specimens are not a gold standard, since they may still permit errors. Tourniquet application time and forearm clench should be verified by all quality laboratory managers in the services. Moreover, the procedure for collecting blood specimens should be revised to eliminate this source of laboratory variability and safeguard the quality.

A case of anaphylactic shock attributed to latex allergy during gastric cancer surgery

Latex allergy is a known cause of allergic contact dermatitis. It produces mild symptoms, including skin rash and itching, which usually subside in a few days. However, latex allergy can also induce anaphylaxis, a severe type I hypersensitivity reaction that can cause urticaria, angioedema, hypotension, tachycardia, and bronchospasm. We report a case of anaphylactic shock during gastric cancer surgery in a patient with no previous allergic history. Surgery was suspended when hypotension, tachycardia, and wheezing developed. A thorough workup revealed that the patient had a latex allergy. The patient subsequently underwent curative gastrectomy performed with latex-free procedures.

Latex gloves allergy in dental workers, Iran

Dermal-respiratory reactions to latex glove is a common problem and sometimes life threatening. Some of the health related past histories such as hand dermatitis, atopy and food allergy increase the probability of these reaction. The purpose of this study was to evaluate reactions to latex gloves amongst dental workers in military dental health centers. In this cross-sectional descriptive survey, dental workers with minimum three months length of employment and most often use of latex gloves were asked to fill standard questionnaire regarding latex related clinical manifestation and personal medical history and predisposing factors. Those with clinical problems did Skin Prick Test (SPT). In this study 330 personnel were assessed. The mean age and length of employment was 31.6 and 8 years, respectively. The most occupation was dentistry. A total of 232 subjects (70.3%) reported latex gloves-allergic symptoms. 72 (21.8%) of persons have history of atopy and food allergy was seen in 114 (34.5%). 63 (19.1%) of subjects reported history of hand dermatitis. All of these had positive regression with allergic responses. Among 73 (34%) symptom positives, 28 (38%) had positive result of SPT. In this survey, the prevalence of allergic reactions is higher than similar studies, which may be due to type of gloves, lack of preemployment assessments and other factors. Because of relationship between allergic reactions to latex gloves and some medical histories, it seems to be necessary for preemployment evaluation and periodic health surveillance of dental workers.

The prevalence of latex allergy in sixth-year medical students: assessment of knowledge, risk, and attitudes about future specialty direction

BACKGROUND

In the prevention of latex allergy, knowledge levels and risk determination for latex allergy of medical students gain importance.

OBJECTIVES

To evaluate the latex allergy knowledge levels of sixth-year medical students and their latex allergy risk.

METHODS

Students completed a questionnaire that assessed basic knowledge of latex allergy and that evaluated latex-related symptoms and latex exposure. The specialty branch students were going to choose in the Medical Specialty Examination was also asked. Skin prick tests (SPTs) with latex and inhalant allergens and patch tests with latex-related products were then performed. Finally, students were asked again about any changes in branch selection after learning their individual risks.

RESULTS

Two hundred twenty sixth-year students were enrolled. Forty-four percent of the students gave the right answer for description of latex. Correct identification of at least 1 latex-related product used outside and inside hospitals was 55.5% and 95.5%, respectively. The prevalence of latex sensitization was 4.4% according to SPT results. The positivity of SPT to any inhalant allergen was 35% (n = 64). None of the students changed their mind about their specialty branch after learning their latex allergy risk.

CONCLUSIONS

Last-year medical students have a remarkably low latex allergy knowledge level, which imposes a serious professional risk. Training strategies based on the benefit to this risk group and reevaluation are strongly recommended before graduation from medical school.

Latex allergy risk assessment in children and adolescents with type I diabetes mellitus

An increased frequency of allergic reactions to latex has been reported in specific populations with chronic latex exposure. However, relevance of latex allergy to children and adolescents with type I diabetes mellitus (DM1) has not been studied yet. The aim of the studty is to assess latex allergy risk in children and adolescents with DM1. Thirty-nine children with DM1 and 35 controls were enrolled. In a case-control study, we applied to all subjects a standard questionnaire, and specific Immunoglobulin E (IgE) concentrations for latex, common aeroallergens, and food-allergens were measured in serum samples. Latex exposure rates by means of medical procedures, operations, and latex glove usage were not different between DM1 and controls. Symptoms due to latex exposure were not determined in both groups. Three (7.7%) subjects in DM1 tested positive for latex-specific antibodies (LSIE), whereas no subject in controls. Diabetics that tested positive for latex-specific antibodies had the disease for three, 5 and 8 years. Nine (23.1%) of diabetics, and two (5.7%) of controls were atopic (p = 0.04). In our investigation, we found that children and adolescents with DM1 are not a risk group for latex allergy, and LSIE in children with DM1 was not accompanied by symptoms of latex allergy, or, presumably, increased risk of latex anaphylaxis.

Latex allergy, a special risk for patients of otorhinolaryngology and head and neck surgery?

A total of 206 patients of the otorhinolaryngology (ORL) department and 204 of the visceral surgery department of the Ludwig Maximilians University of Munich were preoperatively evaluated for latex-specific sensitization. A prick test, a questionnaire, and an enzyme-linked immunosorbent assay immunoprecipitation for IgE antibodies were performed. Latex is a widely spread allergen, and it does not only concern healthcare populations. Within the ORL surgery group, 43 (20.9%) patients were sensitized against latex allergen, and 2 of them were reported to manifest symptoms in consorting with latex. In the cohort of visceral surgery patients, we detected only 23 patients (11.3%) with sensitization against latex. Moreover, most patients were positively detected with the skin prick test (86.4%), whereas the enzyme-linked immunosorbent assay method was less sensitive (18.3%). Patients of the ORL department were considerably more frequently exposed to latex protein particles than patients of the visceral surgery department. This difference attributes to their significant difference in mean age: 44 years in the ORL patients group versus 58 years in the visceral patients cohort. Furthermore, we did not find any correlation to the number of past operations--although undergoing any surgical procedures is a well-known risk factor in other studies about latex sensitization in surgical patients.

A latex-induced allergic airway inflammation model in mice

Latex allergy is important due to serious health impacts and widespread use of its products. Latex allergic reactions can be induced in skin and mucosal surfaces including the respiratory tract. The development of murine models of allergic airway inflammation has provided a framework to dissect out the cellular and molecular mechanisms of allergic respiratory inflammation. In this study we have developed a new mouse model of latex allergic airway inflammation using aerosol inhalation. The allergic inflammatory responses were characterized in this model. Mice were injected intraperitoneally with 0, 10, 50, or 200 microg of latex extract and their serum anti-latex IgE titers were determined. In the second stage, a standard protocol of inhalation was designed and three doses of latex extract solutions including 1%, 0.1%, and 0.01% were used to induce allergic airway inflammation. Bronchoalveolar lavage cytokines (IL-5 and IL-13) and serum anti-latex IgE and IgG(1) titers were determined by ELISA. Eosinophil levels in lung, peripheral blood, bronchoalveolar lavage and bone marrow were also evaluated. Histological analysis of lung tissue was also performed after latex inhalation. The aerosol inhalation of 1% latex allergens solution and presensitization with 50 mug of latex in this study resulted in the development of allergic airway inflammation characterized by elevated allergen specific IgE and IgG(1), peripheral blood, bronchoalveolar lavage and bone marrow eosinophilia. Histological analysis of the lung revealed an inflammatory response characterized by eosinophil accumulation. Elevated levels of Th2 cytokines IL-5 and IL-13 also were shown in bronchoalveolar lavage samples. These studies demonstrate that sensitization and subsequent aerosol inhalational challenge of latex allergen extract promotes allergic airway inflammation characterized by elevated IL-5 and IL-13 and eosinophils.

Latex allergy: diagnosis and management

Latex allergy is an IgE-mediated immediate hypersensitivity response to natural rubber latex (NRL) protein with a variety of clinical signs ranging from contact urticaria, angioedema, asthma, and anaphylaxis. Major allergens include dipped latex products such as gloves and balloons. In highest risk for NRL allergy are patients with spina bifida, but health care workers and others who wear latex gloves are also at risk. NRL allergic patients may also react to fruits/foods, especially banana, kiwi, and avocado. Diagnosis is made by a positive latex RAST and/or skin prick test or challenge test to NRL. Allergen avoidance and substitution and the use of latex-safe devices including synthetic gloves (vinyl, synthetic polyisoprene, neoprene, nitrile, block polymers, or polyurethane) are essential for the affected patient. Accommodation in the workplace may include the use of powder-free, low-allergen NRL gloves or synthetic gloves. These preventive measures have significantly reduced the prevalence of reported reactions to NRL. Hyposensitization is not yet feasible.

Evaluation of the prevalence of antiwheat-, anti-flour dust, and anti-alpha-amylase specific IgE antibodies in US blood donors

BACKGROUND

Asthma in bakery workers is one of the most frequently occurring forms of occupational asthma in the world. Experience from other countries has shown the prevalence of sensitization (IgE) to bakery-associated allergens (BAAs) (wheat [W], flour dust [FD], alpha-amylase [AA]) in bakery workers to be 5% to 53%, whereas the prevalence in nonoccupationally exposed individuals was estimated to be 1.2% to 6.4%.

OBJECTIVE

To estimate the prevalence of BAA sensitization by measuring BAA specific IgE in the residual serum tubes of volunteer blood donors.

METHODS

Serum samples from 534 volunteer blood donors were measured for anti-W, anti-FD, and anti-AA specific IgE antibodies (in duplicate) using the AlaSTAT microplate assay. Samples with BAA IgE concentrations of 0.35 kU/L or greater were considered positive.

RESULTS

Nineteen of 530 serum samples (3.6%; 95% confidence interval [CI], 3.3%-3.9%) were positive for W (range, 0.38-3.61 kU/L), whereas 31 of 534 (5.8%; 95% CI, 5.3%-6.3%) were positive for FD (range, 0.35-2.34 kU/L) and 5 of 529 (1.0%; 95% CI, 0.9%-1.1%) were positive for AA (range, 0.38-1.59 kU/L). Thirteen serum samples were positive for both W and FD; 1 sample each was positive for W and AA and FD and AA.

CONCLUSIONS

The prevalence of IgE sensitization in serum samples from a relatively large unselected population of volunteer blood donors is 1.0% for AA, 3.6% for W, and 5.8% for FD, which agrees well with data from other countries for sensitization prevalence rates for nonoccupationally exposed individuals.

A Review of Latex Sensitivity Related to the Use of Latex Gloves in Hospitals

Beginning in the 1980s, use of latex gloves to protect health care workers against exposure to blood and body fluids increased. Since then, the number of reported cases of latex sensitivity also has increased. Reactions to latex range from contact dermatitis to anaphylactic shock. Low-powder, powder-free, and non-latex gloves provide alternatives to protect health care workers from occupational latex exposure.

Marked improvement of the basophil activation test by detecting CD203c instead of CD63

BACKGROUND

The flow cytometric basophil activation test by detection of CD63 expression has been developed as an alternative method for in vitro diagnosis of IgE-mediated reactions to various allergens. Despite promising initial studies, the test remains disappointing in terms of sensitivity. CD203c has recently been demonstrated as a specific activation marker of basophils that is rapidly up-regulated after allergen challenge in sensitized patients.

OBJECTIVE

The goal of the present study was to compare basophil activation tests by using either CD203c or CD63 in the diagnosis of immediate-type allergy to latex.

METHODS

Twenty-seven patients (health care workers of our institution) who developed clinical features evocative of allergy after contact with latex were included and classified into two groups. Group 1 (n = 16) comprised true allergic patients who presented with typical signs of immediate allergic reaction associated with a positive skin test (prick test). Group 2 (n = 11) consisted of patients whose clinical history was not typical and had negative skin test. Twelve healthy subjects were also studied as controls. We compared the sensitivity of two triple-staining flow cytometric protocols measuring basophil activation after latex stimulation: CD45-IgE-CD63 and CD45-IgE-CD203c.

RESULTS

The CD203c protocol showed a higher sensitivity than the CD63 protocol (75% vs. 50%). In comparison, latex-specific IgE sensitivity was found to be 69%. Furthermore, the magnitude of the basophil response was significantly higher with CD203c in comparison with CD63. Specificity was 100% for both protocols.

CONCLUSION

Due to superior gating of basophils and a higher range of activation in response to allergen, the basophil activation test is markedly improved by use of CD203c instead of CD63.

Recent developments in latex allergy

PURPOSE OF REVIEW

Immediate allergic reactions to natural rubber latex continue to be an important medical and occupational health problem. In this review we focus on progress made in understanding the significance of occupational exposure and epidemiology, risk groups, diagnosis and prevention of natural rubber latex allergy. We also discuss methods aimed at quantification of clinically relevant natural rubber latex allergens and studies on B-cell epitopes of major natural rubber latex allergens.

RECENT FINDINGS

Prospective studies have been published focusing on the prevention of natural rubber latex allergy. Efforts to identify and characterize new natural rubber latex allergens were continued in several research groups. The use of purified allergens or proteins produced by recombinant DNA technology was assessed in studies aimed at improving the diagnosis of natural rubber latex allergy as well as in developing quantitative methods for the measurement of specific natural rubber latex allergens. For the first time, conformational immunoglobulin E epitopes were identified in a major natural rubber latex allergen, hevein, using a novel chimera-based allergen epitope mapping strategy.

SUMMARY

Measures taken in health care to reduce exposure to natural rubber latex products seem to be effective in reducing the number of new sensitizations. A few new minor natural rubber latex allergens, probably important in allergen cross reactions, were identified, and some nonmedical natural rubber latex products were found to be potentially dangerous to natural rubber latex-allergic patients. Sensitive and specific immunoassays for quantification of clinically relevant natural rubber latex allergens in manufactured products were developed in some laboratories. These assays may eventually replace the nonspecific total protein measurement, currently advocated by health authorities in the indirect estimation of allergen amounts in natural rubber latex products. Knowledge about conformational immunoglobulin-binding B-cell epitopes of major allergens is expected to be helpful in designing optimal reagents to specific immunotherapy.