HLA class II antigens DR4 and DQ8 are associated with allergy to hevein, a major allergen of Hevea latex

Low prevalence of latex allergy in children with spinal dysraphism in non-latex-free environment

BACKGROUND

Studies in the past have shown that children with spinal dysraphism have highly prevalent latex allergy. These children have a spectrum of congenital spinal anomalies, caused by defects in neural tube closure, with an incidence of 1 in 1000 births. Proposed risk factors for latex allergy include multiple surgeries since birth, including an insertion of a ventriculoperitoneal shunt, elevated IgE titers, repeat multiple catheterizations, and atopy. In the 1990 s, studies published in the United States and Europe showed a latex allergy prevalence of over 70% in these patients. On the other hand, studies published years later in other countries showed a declining prevalence of no more than 17%.

OBJECTIVE

Our goal was to prospectively assess the prevalence of latex allergy in children with spinal dysraphism in our non-latex free environment center compared with a control group.

STUDY DESIGN

The study group included 58 children with spinal dysraphism attending our center between 2010 and 2013. Findings were compared to 65 children referred for evaluation of allergic diseases. The parents completed questionnaires assessing personal and familial history of allergic diseases. All children were tested for blood latex IgE-specific antibodies (IMMULITE 2000).

RESULTS

The mean age was 120.9 (67.6) months in the study group and 129.5 (68.5) months in the control group (p = 0.27). The corresponding median number of surgical procedures was 2 (range 0-10) and 0 (range 0-4), and mean duration of clean intermittent catheterization was 52 (72.2) months in the study group. Positive IgE antibodies and clinical allergic reactions were low with very similar prevalence in both groups (Figure).

DISCUSSION

Our results show considerable lower latex allergy and sensitization than studies published in the United States and Europe in the past, despite the fact that our center utilizes minimal avoidance measures for latex allergy. Study limitations include the relatively small number of patients in our single-center study. Moreover, our control group could not include normal volunteering healthy children due to institutional review board refusal.

CONCLUSIONS

Children with spinal dysraphism in our center have a low prevalence of latex allergy. Possible explanations include low latex protein content gloves and catheters used worldwide, including our center, lower number of surgeries, or a disease associated propensity for latex sensitization with a geographically variable genetic association. More studies are needed to validate our conclusion that using minimal avoidance measures, without maintaining a strict latex free environment, seems sufficient to prevent clinical latex allergy, at least in the Mediterranean region.

Latex allergy in children: modalities and prevention

Allergic or immediate hypersensitivity reactions to latex have been reported in children with increasing frequency in the past. The reported prevalence varies greatly depending upon the population studied and the methods used to detect sensitization. Children's subpopulations at particular risk include: atopics, individuals with spina bifida, children undergoing surgical procedure during the neonatal period and individuals who required frequent surgical instrumentations. Latex allergy is also an important medical issue, particularly for healthcare personnel. Sensitization mainly occurs by wound or mucosal contact with latex devices during surgery or by inhalation of airborne allergens released from powdered latex gloves. Regarding diagnosis, the medical history, skin prick test and search for specific serum IgE are crucial but cost effective. The development of a guide listing latex-containing drugs is essential for the primary prevention of allergic reactions. Immunotherapy or specific premedication seems not effective in preventing the risk of anaphylaxis during the perioperative course. The most effective strategy to decrease the incidence of latex sensitization is complete avoidance. This strategy is efficient in patients and also in health care workers and has been applied since 2002 in our pediatric surgical hospital. One of major problem with the latex-free gloves was that surgeons find them considerably more difficult to work with. But today, manufacturers made considerable effort and free-latex gloves with an equal tactile sensation than the latex-gloves are now available. The extra cost of free latex gloves is well counterbalanced as allergen test, long stay hospital for allergic reaction, and worker's compensation are no longer needed. Since the introduction of this program in our institution, no allergic reaction to latex has been reported in 25000 anesthetized children or with the health care workers.

Sensitivity to Bee Venom Antigen Phospholipase A2: Association With Specific HLA Class I and Class II Alleles and Haplotypes in Beekeepers and Allergic Patients

Bee venom hypersensitivity is a clinical entity of outstanding importance because bee stings are a leading cause of mortality worldwide. Individuals with immediate-type bee venom hypersensitivity, beekeepers, and healthy controls were examined for HLA-DRB1, DQB1, and DQA1 alleles by sequence-specific oligonucleotide probe typing. Defined hypersensitivity to bee venom antigen phospholipase A2 (vbPLA2) is significantly associated with the presence of susceptible HLA class II alleles: DRB1*0101 (RR = 2.7, p < 3 x 10(-3)), DRB1*0103 (RR = 21.2, p < 7.5 x 10(-11)), DQA1*0101 (RR = 1.2, p < 38.52 x 10(-10)), and DQB1*0501 (RR = 4, p < 2.18 x 10(-10)). Some HLA class I alleles were also associated with risk to bee venom allergy: A*01 (RR = 2.4, p < 7.5 x 10(-4)), B*57 (RR = 35.1, p < 3.5 x 10(-7)), and B*5901 (p < 3.5 x 10(-5)), but they are probably of secondary significance. Three- (DRB1*0103-DQA1*0101-DQB1*0501) (RR = 21.24, p < 7.5 x 10(-11)) and five-loci (A*01-B*59-DRB1*0103-DQA1*0101-DQB1*0501) (p < 2.3 x 10(-6)) extended haplotypes are also significantly carried by vbPLA2 allergic patients. When HLA allele frequencies from patients are compared with those from beekeepers, only HLA-DRB1*0103 (RR = 11.7, p < 8.5 x 10(-5)) and HLA-DQA1*0101 (p < 0.02) were significantly increased in the former. These observations emphasize the importance of the DRB1*0103-DQA1*0101-DQB1*0501 haplotype as a strong candidate for susceptibility to vbPLA2 hypersensitivity, at least in our region.

Characterization of B- and T-cell responses and HLA-DR4 binding motifs of the latex allergen Hev b 6.01 (prohevein) and its post-transcriptionally formed proteins Hev b 6.02 and Hev b 6.03

BACKGROUND

Multiple immunoglobulin E (IgE)-binding proteins in natural rubber latex extracts have been identified. In the case of Hev b 6 a differentiation was made between the precursor protein prohevein (Hev b 6.01) and its two post-transcriptionally formed proteins, the N-terminal hevein (Hev b 6.02) and the C-terminal domain (Hev b 6.03). All three components act as independent allergens. The aim of this study was a detailed analysis of the T-cell responses and the IgE-binding capacity of Hev b 6.01, Hev b 6.02 and Hev b 6.03 by using these allergens as recombinant maltose-binding fusion (MBP) proteins and the usage of synthetic modified hevein peptides.

METHODS

Latex-allergic health care workers (HCWs) suffering from rhinitis, conjunctivitis, contact urticaria and/or asthma with increased specific IgE-antibodies to latex were tested for their IgE-binding capacity and T-cell reactivity (by proliferation response) to the recombinant MBP-rHev b 6.01, MBP-rHev b 6.02, MBP-rHev b 6.03, to native Hev b 6.02, to modified hevein peptides and wheat germ agglutinin (WGA). For testing of the human leucocyte antigen (HLA) class II restriction of MBP-rHev b 6.01 induced peripheral blood mononuclear cell (PBMC) responses, monoclonal antibodies against HLA-DR, HLA-DP or HLA-DQ were added.

RESULTS

Seventeen of 18 (94%) serum samples from latex-allergic HCWs had increased levels of specific IgE to MBP-rHev b 6.01, 16 (89%) to MBP-rHev b 6.02 and 13 (72%) to MBP-rHev b 6.03. A significant difference existed between the specific IgE-values of MBP-rHev b 6.02 and MBP-rHev b 6.03 (P < 0.01). Proliferation responses of PBMC of the same 18 latex-allergic patients were positive for MBP-rHev b 6.01 and MBP-rHev b 6.03 in 83 and 67% of the tested PBMC suspension, whereas the proliferation responses induced with MBP-rHev b 6.02 or native Hev b 6.02 were very low (5.6 and 22.2%). Sera from nine additional latex-allergic patients showed specific IgE binding to the native Hev b 6.02, but none of these sera showed specific IgE binding to the modified Hev b 6.02-peptides [whereby all eight cysteine residues were substituted by serine (C --> S) or by alanine (C --> A)]. Proliferation responses induced by the modified Hev b 6.02 peptides were not significantly different from that induced by Hev b 6.02. Potential HLA-DR4Dw4(DRB1*0401)-restricted T-cell epitopes of Hev b 6.01 predicted by two computer algorithms were only found in the Hev b 6.03-part of Hev b 6.01.

CONCLUSION

In the Hev b 6.01 precursor the regions responsible for IgE binding and those for inducing the T-cell proliferation responses are settled in different parts of the protein. The Hev b 6.02 domain is responsible for IgE binding and carries discontinuous B-cell epitopes whereas Hev b 6.03 is a better inducer of a proliferation response and contains HLA-DR4-binding motifs.

HLA-DQ8 and the HLA-DQ8-DR4 haplotype are positively associated with the hevein-specific IgE immune response in health care workers with latex allergy

BACKGROUND

Hevein is one of the most important latex allergens affecting health care workers (HCWs).

OBJECTIVE

Because the genetically determined susceptibility is one important factor regulating type I allergy, the association between the hevein-specific IgE immune response and HLA class II alleles of DQB1 and DRB1, DRB3, DRB4, and DRB5 was studied.

METHODS

The distribution of HLA-DQB1 and DRB1, DRB3, DRB4, and DRB5 in 269 HCWs with latex allergy, 56 latex-sensitized patients with spina bifida (SB), and 90 nonatopic control subjects under special consideration for hevein-specific IgE was examined.

RESULTS

Seventy percent (189/269) of the HCWs with latex allergy and 39% (22/56) of the latex-sensitized patients with SB had increased hevein-specific IgE antibody concentrations (>0.35 kU/L). HLA data analysis revealed significantly increased phenotype frequencies for DQB1*0302 (DQ8; 91/189 [48%]) and DRB1*04 (DR4; 102/189 [54%]) in hevein-positive HCWs with latex allergy compared with the 80 hevein-negative HCWs with latex allergy (DQB1*0302: 16/80 [20%], corrected P value [P (c)] = 7.1 x 10(-4); DRB1*04: 23/80 [29%], P (c) =.01) and with control subjects (DQB1*0302: 16/89 [18%], P (c) = 1 x 10(-4); DRB1*04: 22/90 [24%], P (c) = 3.2 x 10(-4)). The DQ8-DR4 haplotype frequency was significantly elevated in HCWs with hevein-specific IgE antibodies when compared with that in HCWs without hevein-specific IgE antibodies (47% vs 18%, P (c) = 5.3 x 10(-4)) or control subjects (47% vs 18%, P (c) = 9.6 x 10(-4)). In contrast, latex-sensitized patients with SB with hevein-specific IgE antibodies showed an increased but not significant DQB1*0302 frequency (7/22 [32%] vs 2/34 [6%], P =.02, P (c) = not significant) compared with that seen in those without hevein-specific IgE antibodies.

CONCLUSION

The DQB1*0302 (DQ8) alone, the DQB1*0302 (DQ8)-DRB1*04 (DR4) haplotype, or both are significantly involved in the hevein-specific IgE immune response in HCWs with latex allergy.

Severe anaphylactic shock without exanthema in a case of unknown latex allergy and review of the literature

We describe a case of severe anaphylactic shock without exanthema in an 8-year-old boy who was undergoing elective surgery for an ileostomy. The boy had a history of four anorectal operations in the newborn period, but no history of allergies. Sudden, profound bronchospasm and cardiorespiratory collapse occurred 30 min after the beginning of the operation. No signs of exanthema or urticaria were seen. The patient was resuscitated successfully and remained ventilated for 25 h. During this time, he needed epinephrine in dosages of 0.3-0.05 microg.kg-1.min-1. Radioallergosorbent (RAST) tests for the patient were positive Cap Class 3 and 4, and specific immunoglobulin E was highly positive, suggesting a natural rubber latex allergy as the cause of the anaphylactic shock. Ethylene oxide was negative. Eleven days later, a further operation was performed with a strict latex-free protocol in the presence of histamine 1 and 2 receptor antagonists. On this occasion, the intraoperative course was uneventful. Incidence of anaphylactic reactions, prevalence of latex sensitization, special risk groups and management are discussed.

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.

High-resolution sequence typing of HLA-DQA1 and -DQB1 exon 2 DNA with taxonomy-based sequence analysis (TBSA) allele assignment

High-resolution DNA sequencing of exon 2 of DQA1 and DQB1 genes that uses a taxonomy-based sequence analysis (TBSA) method to assign alleles was developed. The system uses fewer primers for polymerase chain reaction (PCR) amplification and sequencing than other methods and yields accurate DQA1 and DQB1 typing when either homozygous or heterozygous DNA samples are tested. The approach was initially corroborated by the correct typing of 10 blinded samples that had been previously typed by PCR using sequence-specific oligonucleotide probes (PCR-SSOP) or serology, and subsequently confirmed by sequencing of cloned PCR products. DNA from peripheral blood cell samples of 130 individuals enrolled in a case-control analysis of HLA determinants of abdominal aortic aneurysm were subsequently evaluated. Overall, 8 different DQA1 and 19 DQB1 alleles were identified. All 21 DQA1 heterozygous combinations and 45 of 49 DQB1 heterozygous combinations were successfully resolved with TBSA. The two pairs of heterozygous DQB1 combinations that were not unambiguously typed required sequence specific PCR amplification for correct allele identification. We conclude that the method provides precise analysis for HLA-DQ typing.

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.

Latex antigens: identification and use in clinical and experimental studies, including crossreactivity with food and pollen allergens

LEARNING OBJECTIVES

The purpose of this review is to introduce the reader to the range of latex allergens that have been identified by polypeptide sequencing. This knowledge is important for the assessment of clinical latex hypersensitivity, including crossreactivity with food and aeroallergens.

DATA SOURCES

Medline search and relevant publications and reviews from the English medical literature since 1989.

RESULTS

Of the more than 150 polypeptides in natural latex rubber, 35 or more can act as allergens and are recognized by IgE antibodies in the sera of latex-sensitive subjects. Complete or partial amino acid sequence data have now been obtained for 20 or more allergens, and have facilitated cloning of genes and development of allergen-specific antibodies. In latex-sensitive adults, hevein (Hev b6), rubber elongation factor (Hev b1) and Hev b5 are reported as major allergens, while in children with spina bifida, latex particle proteins are important allergens. Although incomplete, the data for finished latex products indicate that the number as well as diversity of latex antigens are limited compared with the allergen profile of natural rubber latex. Latex allergen sequence data allows epitope mapping, which establishes the molecular basis for understanding crossreactivity between latex, food, and aeroallergens.

CONCLUSION

The identification of latex allergens is paving the way for studying the molecular basis of immunoreactivity to these proteins, including crossreactivity with food and other allergens. The development of reagents to detect and measure antigen-specific responses will increase diagnostic specificity of allergic reactions to latex products.

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 number 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.

Longitudinal study on latex sensitization in children with spina bifida

The course of latex sensitization is rarely documented, and only a few reports about the influence of prophylaxis in the occupational environment have been published concerning health care workers. Therefore we did a follow-up study in the high risk group of patients with spina bifida and evaluated the efficacy of latex prophylaxis. For this purpose we measured IgE antibodies (FEIA) against latex and inhalative allergens in the sera of 67 patients with spina bifida and reevaluated them 0.6 to 4.1 years later, having instructed the patients about prophylactic measures and established a latex-free environment for surgery of all spina bifida patients in our hospital. 37% of the patients did not develop latex antibodies during the follow-up period, 27% showed decreasing levels of antibodies (12% to non-detectable levels), 19% had an increase in latex sensitization (6% newly sensitized), and 9% showed no change in levels of latex antibodies. From our data it may be concluded that surgery without strict latex prophylaxis is the main cause of new sensitization and worsening of preexisting latex antibody levels. Mild sensitization can be reduced by prophylactic measurements to non-detectable antibody levels. With consistent prophylaxis, even symptomatic patients can be operated without risk of allergic complications or increasing antibodies.

Molecular analysis of DRB and DQB1 alleles in German spina bifida patients with and without IgE responsiveness to the latex major allergen Hev b 1

BACKGROUND AND OBJECTIVE

Spina bifida patients are at a high risk of developing latex allergy. Recently, we found a relationship between the IgE responsiveness to latex allergen hevein and human leucocyte antigen (HLA) alleles DRB1*04(DR4) as well as DQB1*0302(DQ8). This study was carried out to investigate the association between HLA class II alleles and the specific IgE response to latex allergen Hev b 1 in spina bifida patients.

METHODS

Blood samples from 103 unrelated German spina bifida patients exposed to latex products and from 90 unsensitized controls were examined. Genomic DNA isolation followed by HLA-D-specifc polymerase chain reaction (PCR) amplification was used to perform HLA typing of allelic polymorphisms in exon 2 of DQB1 and of DRB1,3,4,5 with sequence-specific oligonucleotide probes (SSOPs).

RESULTS

Fifty-one out of 103 spina bifida patients were found to have anti-latex IgE antibodies; 40 had also anti-Hev b 1 antibodies. Further, we observed that 80% of the Hev b 1 responders underwent five or more surgeries whereas 55% of the Hev b 1 non-responders and 75% of the latex-non-responders underwent less than five surgical interventions. From the latex-sensitized group 33% showed an elevated phenotype frequency of DRB1*0701(DR7) when compared with unsensitized patients (12%, P = 0.0095, Pc = NS) and with controls (17%; P = 0.035, Pc = ns). Fifteen out of 40 Hev b 1 responders also exhibited an elevated DR7 frequency when compared with latex-sensitive but Hev b 1-negative patients (38% vs 18%, P = NS) or with unsensitized controls (38% vs 17%, P = 0.013, Pc = NS).

CONCLUSIONS

Although we found that the DRB1*0701 (DR7) phenotype frequency was elevated in SB patients with latex- as well as with Hev b 1-IgE responsiveness, the analyses of the other class II alleles clearly demonstrate that the HLA-D region does not play a major role in the pathogenetic way of sensitization to Hev b 1.

On the allergenicity of Hev b 1 among health care workers and patients with spina bifida allergic to natural rubber latex

BACKGROUND

Recent studies have caused much controversy about the prevalence of IgE antibodies to Hev b 1 among health care workers (HCWs) and patients with spina bifida (SB) who are allergic to latex. This investigation was carried out to verify the results reported.

METHOD

Serum samples from 140 patients with SB as well as from 105 HCWs allergic to latex were tested by enzyme allergosorbest test (EAST) and EAST-inhibition assay to evaluate the rate and degree of sensitization to highly purified Hev b 1.

RESULTS

Eighty-one percent of patients with SB who were allergic to latex had IgE antibodies against Hev b 1. The prevalence of anti-Hev b 1 antibodies among HCWs allergic to latex was 52.3%. In 15 of 33 serum samples from patients with SB that were randomly tested, the IgE binding to commercial latex allergens could be completely inhibited by Hev b 1; in only six cases was the maximum inhibition of IgE binding to latex by Hev b 1 less than 50%. Testing two monoclonal anti-Hev b 1 antibodies with extracts of five brands of latex gloves revealed a predominant presence of Hev b 1 protein as a monomer or its aggregates. Molecular analysis of human leukocyte antigen-D region genes DRB and DQB1 suggested no statistically significant correlation between the human leukocyte antigen alleles tested and IgE responsiveness to Hev b 1.

CONCLUSIONS

Our results indicate that Hev b 1 not only makes significant contributions to the IgE binding to latex, but it is also the unique sensitizer in about 45% of patients with SB who are allergic to latex.