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

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.

Latex allergy in children: a follow-up study

BACKGROUND

Natural rubber latex allergy is an important health problem. Multiple contacts with latex in childhood are a risk factor. Many aspects of this disease are still unknown, one of which is the clinical outcome of these children. The aim of this study was to evaluate the clinical and epidemiological features of latex allergy and compliance with latex avoidance instructions in allergic children.

MATERIAL AND METHODS

Seventeen consecutive patients with a history of latex allergy, fruit allergy or chronic urticaria were selected. The patients underwent a skin prick test and determination of specific-IgE to latex at the start and at end of the study (median follow-up: 3 years). At diagnosis, patients with a positive result to one of the tests and a clinical history of latex allergy were considered allergic; patients with a positive test but without a clinical history suggestive of allergy were considered sensitized. These children were given latex avoidance instructions.

RESULTS

Eleven children (64.7 %) were classified as allergic and 6 (35.3 %) as sensitized. Five patients had undergone latex-free surgery after diagnosis without incident. During follow-up, 11 patients (8 allergic and 3 sensitized) had contact with latex. Contact occurred in the home in 10 children, and all were symptomatic. Specific-IgE levels to latex at the end of the study were significantly higher in patients who had contact with latex during the follow-up period than in those without latex contact.

CONCLUSIONS

Strict compliance with latex avoidance instructions is essential both inside and outside the hospital. Greater emphasis should be placed on reducing latex exposure in the home and school environments, as such contact could maintain positive IgE-antibody levels.

SCUBA diving for individuals with disabilities

Self-contained underwater breathing apparatus (SCUBA) diving has become an increasingly popular recreational activity, enjoyed by millions of individuals. There has also been a growing interest in SCUBA diving in the disabled population for rehabilitation and recreation. This review discusses medical issues relevant to individuals with disabilities who wish to participate in SCUBA diving. In addition, specialized equipment, adaptations in techniques, and additional precautions will be presented. SCUBA diving can be an enriching experience, potentially helping to improve self-image and quality of life. Knowledgeable healthcare professionals can help to guide their patients who are interested in SCUBA diving.

Type I latex allergy in health care workers with latex-induced contact urticaria syndrome: a follow-up study

BACKGROUND

Latex allergy is an important occupational health issue among health care workers (HCWs). Secondary prevention in sensitized/allergic individuals involves avoiding exposure to NRL products.

AIMS OF THE STUDY

The aim of this follow-up study is to determine the long-term health consequences in HCWs with type I latex allergy with latex-related contact urticaria syndrome, of providing appropriate information and practical avoidance education.

METHODS

Seventeen HCWs with latex-induced contact urticaria syndrome, as ascertained by the glove use test, were investigated. Initial and follow-up visits included: a detailed questionnaire, skin prick test (SPT) with glove eluates and with commercial latex extract, SPT with common inhalant and food extracts, serum specific immunoglobulin (Ig)E to latex and some foods and the glove use test.

RESULTS

On re-examination, 11 (64.7%) subjects showed positive SPTs to extemporaneous extract and 10 (58.8%) patients showed a positive SPT to commercial extract. Of the nine patients with detectable levels of serum latex specific IgE at first evaluation, four (44.4%) became negative and four were assigned to at least one class lower. Only one (11.1%) employee had higher radioallergosorbent test values than those at the latex allergy diagnosis. At follow-up, the 17 individuals had positive latex challenge results, although the duration of exposure causing a reaction increased.

CONCLUSION

Our study shows that preventive measures are sufficient to induce a reduction of sensitization. Continued avoidance is needed to prevent re-sensitization or adverse reactions on re-exposure.

Caring for a child with spina bifida: understanding the child and carer

Spina bifida is a common congenital abnormality, which causes significant physical and psychological morbidity in affected children and which also affects their carers. This small-scale study looked at the health problems of a child with a myelomeningocoele. It also addresses the psychosocial problems that his mother, his main carer, faced and the social networks involved in his care. The evidence supporting various aspects of spina bifida prevention and management is explored. Furthermore, a literature review is included, with regards to physical and psychological issues for child and carer. This study aims to raise awareness of the problems faced by children with myelomeningocoele and their families. In particular, we aim to educate health care professionals on the importance of perceived stress by carers of such children, and suggest ways to reduce psychosocial morbidity.

Minimizing latex exposure and allergy. How to avoid or reduce sensitization in the healthcare setting

Healthcare professionals with long-term exposure to natural rubber latex products and patients who undergo multiple operations are at high risk for latex allergy. The clinical spectrum of this allergy ranges from self-limited contact urticaria to involvement of multiple organ systems in anaphylaxis. In this article, Dr Muller explores the roots of the latex allergy epidemic and offers insight into the manufacturing process of latex gloves. She also presents a clinical approach to prevent or ameliorate sensitization and manage allergic symptoms.

Cross-reactivity between gutta-percha and natural rubber latex: assumptions vs. reality

BACKGROUND

Immunological cross-reactivity between gutta-percha and natural rubber latex, or NRL, has not been demonstrated clearly despite recent concerns and several suspected cases reported in the literature.

METHODS

The authors analyzed aqueous extracts of commercial gutta-percha points and raw gutta-percha samples for cross-reactivity to NRL by radioallergosorbent test, or RAST, inhibition; immunoblot inhibition; direct enzyme-linked immunosorbent assay, or ELISA; and ELISA inhibition using sera from NRL-allergic people as the source of anti-NRL immunoglobulin E, or IgE, antibodies. To confirm in vitro results, the authors conducted skin prick testing, or SPT, on a patient with type I NRL allergy using aqueous extracts from raw gutta-percha, ammoniated gutta-percha and gutta-percha points.

RESULTS

Aqueous extracts from commercial gutta-percha points did not cross-react to NRL in RAST inhibition or immunoblot inhibition, ELISA or ELISA inhibition assays. However, three of 13 sera from subjects with type I NRL allergy exhibited IgE binding to raw gutta-percha extracts in direct ELISA. Moreover, in ELISA inhibition, the binding of IgE to raw gutta-percha extracts was inhibited in a dose-dependent manner by raw NRL and vice versa. SPT results from a subject with type I NRL allergy were positive for NRL and raw gutta-percha extracts but negative for gutta-percha point extracts.

CONCLUSIONS

The authors found no detectable cross-reactivity between NRL and commercial gutta-percha points. However, their ELISA and SPT results demonstrated that some allergenic cross-reactivity exists between raw gutta-percha and raw NRL.

CLINICAL IMPLICATIONS

Gutta-percha alone is not likely to induce symptoms in patients with type I NRL allergy. However, other materials used in obturating root canals may be irritating and potentially allergenic in patients with pre-existing allergies.

Outcome of a latex avoidance program in a high-risk population for latex allergy - a five-year follow-up study

BACKGROUND

Children with a shunted hydrocephalus are at highest risk for developing an immediate type allergy to latex. Limited data are available for preventive or therapeutical approaches.

OBJECTIVE

To evaluate the effectiveness of latex avoidance, with special regard to status of sensitization and compliance.

METHODS

In 1995, 131 children with a shunted hydrocephalus were screened for sensitization to latex by skin prick test and determination of specific IgE. Patients and parents were instructed on latex-avoiding strategies. Hospital physicians, family doctors and dentists were advised to perform further surgical and other medical interventions under latex-free conditions. In 2000, 100 of these 131 patients were re-evaluated according to the same testing procedures. Special attention was directed at the extent prophylaxis had been performed.

RESULTS

In 1995, 30/100 patients re-evaluable in 2000 proved sensitized to latex, 70 had negative testing results. In 2000, 64/70 patients were still negative, six had meanwhile developed latex-specific IgE. Seven out of thirty subjects with former positive testing had changes within the same RAST-class, 20 showed a decline of at least one RAST-class, whereas in three cases an increase of latex-specific IgE was found. However, only 34 patients, mainly those being already sensitized, had thoroughly followed both medical and private prophylaxis. Within this group, 16 subjects (47.1%) had improved and another nine (26.5%) were still negative. Only three (8.8%) already previously sensitized patients presented with a further increase of latex-specific IgE. Medical prevention contributed more to the outcome than home prevention. No statistically significant correlation with latex-avoidance was observed, however, in previously unsensitized subjects. Underlying disease, atopy, number of operations, and age did not prove as significant variables.

CONCLUSION

Secondary prevention results in a decrease of specific IgE in latex-sensitized patients with hydrocephalus. This is due to medical more than home prophylaxis. Sensitization obviously occurs mainly in early childhood, thus primary prevention remains to be the main target.

[Peculiarities of latex allergy and preventive measures in the pediatric age group]

Latex allergy can be considered a problem of public health in at-risk populations. Although the figures on prevalence vary, approximately 1 % of the general population is sensitized to latex. To date, two determining factors for latex sensitization have been identified: an atopic predisposition and the number of operations. Among atopic patients or those at-risk for allergy, the prevalence of latex sensitization is between 3 and 20 times higher than that among the general population. Nevertheless, the effect of this factor seems to be modulatory and the determining factor seems to be the number of operations that children have undergone; the critical number is 5-6 interventions, after which the probability of sensitization increases considerably.All children who have undergone multiple operations should be considered as being at-risk. Children with spina bifida are especially at-risk. The reasons for this are still a matter of debate: the disease itself has been postulated as a specific risk factor, although other, possible associated factors could be determinant in triggering latex sensitization (the presence of a ventricular-peritoneal shunt, age at which surgery was performed, type of operation, etc.). Children with spina bifida and latex allergy show considerable differences in type of allergic sensitization; these differences seem to result from the different route of sensitization and could explain the variations observed in the clinical manifestations between children and adults: children become sensitized mainly by direct contact between latex particles and blood vessels and open mucosae while in adults the process takes place transcutaneously or by inhalation of aerosol particles. Consequently, the most frequent manifestation in children is urticaria while contact dermatitis and respiratory symptoms predominate in adults. Studies performed with immunoblotting have confirmed that children have IgE that almost constantly recognize low molecular weight latex proteins (14, 15 and 27 Kd) while this finding is less frequent in adults.The preventive measures in the pediatric population focus on avoidance of latex, especially in hospitals. Today, latex is ubiquitous, making complete avoidance difficult. When necessary, and whenever a latex-free environment cannot be guaranteed, presurgical medication can be used, although its utility is debatable. Although further studies are required, specific immunotherapy is one therapeutic possibility that may in future be used in children with latex allergy.

Hev b 7 is a Hevea brasiliensis protein associated with latex allergy in children with spina bifida

BACKGROUND

In addition to their disease-associated handicaps, patients with spina bifida (SB) are at high risk of developing latex allergy. Individuals with SB represent a special group of latex-allergic patients, inasmuch as their IgE-binding patterns differ from those of other populations of latex-allergic individuals. Two allergens strongly associated with latex allergy in patients with SB--Hev b 1 and Hev b 3--have already been identified.

OBJECTIVE

We intended to identify a predominant IgE-binding band--in addition to Hev b 1 and 3--at 43 kDa in a study population of 38 latex-allergic (IgE antibodies to latex and symptoms on provocation with latex gloves) and 15 latex-sensitized (IgE antibodies to latex but no symptoms on provocation) children with SB (mean age, 12.3 years) and to determine its frequency of recognition.

METHODS

Sera of latex-sensitized or latex-allergic patients with SB were tested on latex C extract containing natural Hev b 1, Hev b 3, and Hev b 7 and with the recombinant 43-kDa Hev b 7 in immunoblot and inhibition studies.

RESULTS

Natural Hev b 1 was recognized by 82% and natural Hev b 3 by 79% of the latex-allergic children with SB. In addition to some other proteins, 15 (39.5%) of 38 latex-allergic and 2 (13%) of 5 latex-sensitized children with SB revealed IgE binding to a 43-kDa band in the latex protein extract. We identified this 43-kDa IgE-binding band as natural Hev b 7 by immunoblotting and inhibition experiments using recombinant Hev b 7.

CONCLUSION

From these data, we conclude that Hev b 7, the patatin-like Hevea latex protein, is the third SB-associated latex allergen. Future immunotherapy for latex-allergic individuals with SB will have to include Hev b 7 in addition to Hev b 1 and Hev b 3.