In utero repair of myelomeningocele with autologous amniotic membrane in the fetal lamb model.

BACKGROUND: Despite advances in prenatal repair, myelomeningocele (MMC) still produces devastating neurologic deficits. The amniotic membranes (AM) are a biologically active tissue that has been used anecdotally for human fetal MMC repair. This study evaluated the use of autologous AM compared to skin closure in an established fetal MMC model. METHODS: Seven fetal lambs underwent surgical creation of MMC at gestational age of 75days followed by in utero repair at gestational age of 100days. Lambs were repaired with an autologous AM patch followed by skin closure (n=4) or skin closure alone (n=3). Gross necropsy and histopathology of the spinal cords were performed at term to assess neuronal preservation at the lesion. RESULTS: An increase in preserved motor neurons and a larger area of spinal cord tissue were seen in AM-repaired lambs, as was decreased wound healing of the overlying skin. Loss of nearly all spinal cord tissue with limited motor neuron preservation was seen in skin only-repaired lambs. CONCLUSIONS: AM-repaired lambs showed increased protection of spinal cord tissue compared to skin only-repaired lambs, but the overlying skin failed to close in AM-repaired lambs. These results suggest a potential role for AM in fetal MMC repair that warrants further study.

Prenatal latex sensitization in patients with spina bifida: a pilot study.

OBJECT: Patients with spina bifida are particularly vulnerable to developing immunoglobulin E (IgE)-mediated latex sensitization. Even though many risk factors leading to latex allergy in these patients have been described, it is still unclear whether the increased prevalence of latex sensitization is disease associated or due to the procedures used to treat spina bifida. The aim of this study was to assess prenatal latex sensitization in patients with spina bifida by examining IgE levels in umbilical cord blood. METHODS: Patients with spina bifida and matched healthy infants were recruited from the University Medical Center Hamburg-Eppendorf and Children's Hospital Altona. Latex-specific and total IgE were assessed in umbilical cord blood using ImmunoCAP testing to evaluate the degree of prenatal latex sensitization. RESULTS: Twenty-two subjects, 10 with spina bifida and 12 healthy individuals, were included. Subjects were selected after matching for sex, gestational age, weight, parental allergy profile, number of prenatal examinations, and utilization of latex tools during pregnancy (propensity score estimates, p = 0.36). In patients with spina bifida, latex-specific and total IgE levels were significantly higher than those in healthy individuals (p = 0.001). After normalization to total IgE, latex-specific IgE levels were higher, yet not significantly increased (p = 0.085). CONCLUSIONS: Perinatally, there is a significant augmentation of total and latex-specific IgE in patients with spina bifida. After correcting for total IgE, latex-specific IgE was increased, yet not significantly higher than in matched, healthy controls. This pilot study gives novel insights in the immunological reactions related to spina bifida. The increased latex-specific IgE levels could possibly be associated with the occurrence of a latex allergy in the future.

Different in vivo reactivity profile in health care workers and patients with spina bifida to internal and external latex glove surface-derived allergen extracts.

BACKGROUND: Allergy to natural rubber latex is a well-recognized health problem, especially among health care workers and patients with spina bifida. Despite latex sensitization being acquired in health institutions in both health care workers and patients with spina bifida, differences in allergen sensitization profiles have been described between these two risk groups. OBJECTIVE: To investigate the in vivo reactivity of health care workers and patients with spina bifida to extracts of internal and external surfaces of latex gloves and also to specific extracts enriched in major allergens for these risk groups. METHODS: Gloves from different manufacturers were used for protein extraction, and salt precipitation and hydrophobic interaction chromatography (HIC) were applied to obtain the enriched latex extracts. The major latex allergens were quantified by an enzyme immunoassay. The extracts obtained were tested in 14 volunteers using skin prick tests (SPT). RESULTS: Latex glove extracts enriched in the hydrophobic allergens that are most often seen in patients with spina bifida were obtained by selective precipitation, whereas HIC produced extracts enriched in the hydrophilic allergens commonly found in health care workers. The health care workers had positive SPTs to glove extracts from internal surfaces and to the hydrophilic allergen-enriched extracts. By contrast, patients with spina bifida had larger skin reactions both to external glove extracts and to the extracts enriched with the hydrophobic major allergens for this risk group. Despite the protein concentration of these extracts being less than half the concentration of the commercial extract, the weal-and-flare reactions were of similar magnitude. CONCLUSION: Using novel latex extracts, our study showed a different in vivo reactivity pattern in health care workers and in patients with spina bifida to extracts of the internal and external surfaces of gloves, which suggests that sensitization may occur by different routes of exposure, and that this influences the allergen reactivity profiles of these risk groups.

Longitudinal study on specific IgE against natural rubber latex, banana and kiwi in patients with spina bifida.

OBJECTIVE: Up to 2 out of 3 spina bifida (sb) patients with natural rubber latex (NRL) antibodies (ab) have crossreacting IgE-ab against tropical fruit, due to structural homologies between several NRL antigens and allergenic fruit proteins. It is essential to investigate whether the patients were first sensitized against NRL or fruit, to give recommendations for an evidence-based prophylaxis. PATIENTS AND METHODS: We investigated sera of 96 sb patients for specific IgE ab against NRL, banana and kiwi as examples for crossreacting fruit by FEIA (ImmunoCAP System, Phadia). These tests were repeated up to 3 times (mean after 2 years, maximum after 7 years). RESULTS: In the first testing only 2 of 50 NRL-IgE negative patients (4%) had ab against banana or kiwi. 4 of the 46 NRL-IgE positive patients (8%) showed ab against banana (2) or kiwi (2), 3 (7%) against both fruit. Symptoms of fruit allergy were presented by 3 patients, all symptomatic patients had high levels of specific fruit-ab. In the follow-up study 2 patients with low sensitization against NRL lost their NRL ab and their fruit ab, another 2 only the fruit ab, whereas 4 NRL-sensitized patients newly developed ab against banana and 1 against kiwi. Only 2 patients developed ab against fruit without being sensitized against NRL. 7 out of 10 patients with banana and kiwi ab were atopics. CONCLUSIONS: In most cases the sensitization against fruit follows the NRL sensitization. There is no need to recommend sb patients without NRL sensitization to primarily avoid tropical fruit.

IgE-mediated latex allergy--an exciting and instructive piece of allergy history.

Natural rubber latex represents a potent allergen, which for many years had an important impact on occupational health problems but especially on certain risk groups such as spina bifida. Luckily, these problems decreased when powder-free, latex-poor gloves were introduced. Latest data show that in children with spina bifida, who grew up completely latex-free from birth on, sensitization to NRL as well as clinical relevant allergy significantly decreased. Furthermore, sensitization to aeroallergens also went down and even the prevalence of allergic diseases decreased significantly to rates of the general population. This new data clearly indicates that potent allergens (such as latex) in high-risk groups (such as spina bifida) can induce sensitization spreading, and corresponding avoidance can reverse this development. In conclusion, it can be stated that 'new' allergies can suddenly arise, there are allergen-specific risk groups, local IgE-production is also possible in the CNS, allergen avoidance can be very effective in terms of primary prevention, sensitization spreading can be made reversible by effective prevention, and finally, certain allergies can luckily become history within a relatively short period of time. Furthermore, these new findings clearly end the debate about whether patients with spina bifida have a disease-inherited risk for allergy to NRL and show that the cause is the meningi and the multiple surgical interventions - and therefore sequelae can be reversed by implementing preventive measures.

Prevalance of latex sensitization and associated risk factors in Turkish children with spina bifida.

PURPOSE: Among children with spina bifida there is a high prevalence of latex allergy in reports from Europe and USA. The aim of this study was to investigate the incidence of latex sensitization and associated risk factors in children with spina bifida in Middle-Eastern region (Istanbul, Turkey). MATERIALS AND METHODS: Eighty consecutive children affected with spina bifida were included in the study. Data were collected about age, sex, family and personal history of atopy, and the number and type of operations classified as neurosurgical, urological, and orthopedic. All patients underwent skin prick test using latex solutions and cross-reacting foods. Total and latex-specific IgE levels were also measured. RESULTS: Latex sensitization was shown in 16% (13/80) of the patients with specific IgE > 0.7 kU/L. The number of operation, using intermittent bladder catheterization and ventricular-peritoneal shunt were significantly associated with latex sensitization. CONCLUSION: The incidence of latex sensitization in this study was lower than reported in the literature. Environmental factors such as the type and number of operations and geographical location may play a role in the development of latex sensitization.

Prevalence of latex allergy in spina bifida: genetic and environmental risk factors.

AIM OF STUDY: To evaluate the prevalence of latex allergy in a population of children with spina bifida (SB) and to assess the role of early exposure to latex products and others risk factors. INTRODUCTION: SB is related with an higher incidence of latex allergic reactions. These patients received repeated surgical procedures, implant of latex-containing materials and catheterization. MATERIALS AND METHODS: Eighty consecutive subjects affected with SB besides answering a questionnaire, underwent a skin-prick test (SPT) to latex and the determination of the specific serum IgE (RAST CAP) to latex. 40% (32/80) of the patients showed a latex sensitization with specific IgE > 0.7 kU/I but only twelve of the 32 sensitized patients (40%) suffered from clinical reactions to latex (urticaria, conjunctivitis, angioedema, rhinitis, bronchial asthma). Number of surgical procedures, but particularly early exposure to latex and familiarity for allergy are correlated with latex allergy (p < 0.01). CONCLUSION: Latex allergy in SB children is multifactorial situation related with a disease-associated propensity for latex sensitization, early exposure and number of surgical procedures. Prophylactic measures to avoid the exposure, not only in the sanitary environment, through the institution of latex-safe routes and every day, prevent potentially serious allergic reactions.

Early exposure to latex products mediates latex sensitization in spina bifida but not in other diseases with comparable latex exposure rates.

BACKGROUND: The high prevalence of latex sensitization in patients with spina bifida (SB) has been attributed to repeated and early exposure to latex products. Other diseases such as gastroschisis/omphalocoele and post-haemorrhagic/congenital hydrocephalus are also associated with repeated and early latex exposure. OBJECTIVE: The aim of the study was to evaluate whether the high prevalence of latex sensitization in patients with SB is rather related to the underlying disease itself than to disease-associated known risk factors. METHODS: We compared children with SB (n=35), children with gastroschisis/omphalocoele (G/O, n=20) and children with post-haemorrhagic/congenital hydrocephalus (PH, n=45). All children with SB and PH had a ventriculo-peritoneal shunt since a very young age. Patients who underwent three or less surgical procedures matched in terms of age, number of operations, atopy and gender distribution, and were analysed for IgE sensitization rates to latex. RESULTS: In the SB group, 16 of 35 patients (46%) showed elevated latex-specific IgE antibodies in contrast to one of 20 patients (5%) in the G/O group and four of 45 patients (8.9%) in the PH group (P<0.0005 and P<0.005, Fisher's exact test). Comparing matched control groups (

Patterns of latex allergen recognition in children sensitized to natural rubber latex.

Single recombinant latex allergens permit the study of the pattern of sensitization to individual allergens. We aimed to quantify the IgE-response to individual latex allergens in children sensitized to latex. The study group included 31 latex-sensitized children: 26 operated at least twice, 20 of them with spina bifida; two children with one operation and three atopic non-operated children. IgE antibodies to rHev b 1, rHev b 3, rHev b 5, rHev b 6.01, rHev b 7.02 and rHev b 8, coupled to ImmunoCAPs, were measured in each serum. IgE responses to rHev b 1, rHev b 5 and rHev b 6.01 were found in 17 children each, and their mean +/- s.d. levels were 5 +/- 7.4, 16.8 +/- 14 and 10 +/- 18 kU/l, respectively. IgE responses to rHev b 3 (4 +/- 5.4 kU/l) were found in eight children. Two children had IgE to rHev b 7 (1.7 and 3.2 kU/l), and none to rHev b 8. Four sera were negative to all tested recombinant allergens. We divided the patients in three groups: sensitized only to rHev b 1, sensitized only to rHev b 5 and/or rHev b 6.01, and sensitized to both rHev b 1 and to rHev b 5 and/or rHev b 6.01. The three groups had the same profile of clinical features. Hev b 5 induces the quantitatively higher IgE responses in children with multiple surgeries sensitized to latex. Responses to Hev b 6.01 equal those of Hev b 1.

Low prevalence of latex sensitivity in South African spina bifida children in Cape Town.

Spina bifida children have a high prevalence of latex allergy in studies reported from Europe and the USA. This study investigated the prevalence of latex allergy in a cohort of 24 spina bifida children at the Red Cross Children's Hospital from Cape Town, South Africa. The children were investigated using a detailed questionnaire, skin prick tests (ALK-Abello), ImmunoCap RASTs, Western blotting and ELISA, using the purified latex proteins Hev b1 and Hev b3 and whole latex preparation. A low overall prevalence of latex sensitization of 16.7% was found in the children. Children who were sensitive reacted to water insoluble to Hev b1 and Hev b3 proteins. The low prevalence of latex sensitization in the South African children may not be entirely explained by stringent latex avoidance. The children were from a low socioeconomic social status and 'hygiene' and other factors should be considered.

Latex allergy and associated risk factors in a group of Turkish patients with spina bifida.

Allergic reactions to latex are common in patients with spina bifida. Its incidence varies between 28% and 67%. The aim of this study was to investigate the incidence of latex allergy and its risk factors in patients with spina bifida in Izmir, Turkey. Forty-six patients (24 male, mean age 10 years) were included in the study. A questionnaire was completed and skin prick tests with latex solution and cross-reacting foods were performed. Total IgE levels, specific IgE to common aeroallergens (Phadiotop), and latex specific IgE levels were measured. Patients with positive skin test reaction and/or who had specific IgE to latex without clinical symptoms were considered as sensitive to latex. The patients who also had clinical symptoms with latex exposure were diagnosed as allergic to latex. Latex sensitivity was found in 5/46 patients (10.8%). Only two patients had latex allergy (4.3%). Total IgE levels were higher (median 157 vs. 40 kU/L, p=0.012) and the duration of clean intermittent catheterization was longer insensitized patients when compared to non-sensitized patients (median 8 vs. 3 years, p=0.015). Specific IgE to common aeroallergens and positive skin prick test to cross-reacting foods were more prevalent in sensitized than in non-sensitized patients (p=0.02 and 0.015, respectively). The incidence of latex allergy in our group was lower than reported in the literature. This result may be due to the low number of surgical interventions. High levels of total IgE, positive Phadiotop, positive skin prick test to cross-reacting foods and the duration of clean intermittent catheterization are the risk factors for latex sensitivity in patients with spina bifida.

Assessment of profilin as an allergen for latex-sensitized patients.

BACKGROUND: The presence of the actin-binding protein, profilin, has been demonstrated in natural latex extracts; but the clinical significance of this molecule as an allergen for latex-allergic patients is not clear. We studied the allergenic relevance of isolated latex natural and recombinant profilin, by in vivo and in vitro techniques, in two populations of spina bifida children (SB) and adults allergic to latex (AL). METHODS: Profilin is present in small amounts in latex extracts obtained from low ammoniated (LA) natural latex. Its purification by affinity chromatography resulted difficult due to Heb v 1 unspecific binding. Therefore a method was developed to obtain natural profilin from natural latex, combining affinity chromatography (PLP, poly-L-proline Sepharose column) and previous ammonium sulfate fractionation. Alternatively, latex c-serum containing a low amount of Hev b 1 and a relatively higher profilin content could be used. Recombinant latex profilin isoform (rHev b 8) was cloned by PCR amplification. The entire coding region of Hev b 8 was subcloned into the expression vector pKN172 and a non-fusion form of Hev b 8 was expressed in Escherichia coli BL21 (DE3). Purified recombinant protein was obtained after a single passage through PLP-Sepharose column. RESULTS: Natural and recombinant purified Hev b 8 were tested cutaneously by intradermoreaction (ID) in 17 SB and 14 AL patients. They were positive in 15 SB and 14 AL patients. No wheals were produced when tested in nonatopic control patients. Only 42% of sera from latex-allergic patients revealed specific IgE titers of class 1 or higher by enzyme immunoassay and only 39% of them exhibited IgE binding by SDS-PAGE immunoblotting with any natural or recombinant Hev b 8 forms. CONCLUSION: It seems that profilin is a relevant allergen for both groups of patients from a frequency point of view, but with scarce presence in natural latex extracts and raw sources, with a subsequent low IgE induction capacity.

Efficacy of latex avoidance for primary prevention of latex sensitization in children with spina bifida.

Over 6 years, the prevalence of latex sensitization fell from 4/15 (26.7%) to 1/22 (4.5%) in children with spina bifida treated in a latex-free environment from birth compared with historic controls. These precautions appear to be efficacious for the primary prevention of latex sensitization.

Reduction of latex sensitisation in spina bifida patients by a primary prophylaxis programme (five years experience).

Spina bifida patients represent a group with the highest risk for latex sensitisation and allergy with life-threatening symptoms mostly during surgery. At the end of 1995 we initiated a primary latex prophylaxis around and during surgery and anaesthesia of all spina bifida patients. The aim of our study was to investigate the prevalence of latex sensitisation in the spina bifida patients born during the five years after establishing latex prophylaxis in the Cologne Children's Hospital in December 1995. We investigated 34 serum samples of 27 spina bifida patients (mean age 2.4 years) for specific IgE antibodies against latex allergens (CAP system) and compared these patients born after 1995 with 38 spina bifida patients up to 5 years of age (mean 3.1 years) born before. In the prophylaxis group two of 27 patients (7 %), one of them with two operations outside the Children's Hospital, had low specific IgE against latex ( 100 kU/l (mean 22.6 kU/l, min 0.4 kU/l). Sera of 22 patients remained negative for latex IgE (min. 1, max. 19, mean 4.3 operations). By primary latex prophylaxis during surgery, anaesthesia and in paediatric wards the prevalence of latex sensitisation can be significantly reduced even in the high risk group of spina bifida patients. Problems can arise by the need for surgery in hospitals not experienced in the treatment of spina bifida patients, where latex prophylaxis is neglected.

Latex allergy in pediatric surgery is dependent on repeated operations in the first year of life.

BACKGROUND/PURPOSE: Patients with spina bifida represent the highest risk group for hypersensitivity to latex. Recognized risk factors for these patients are repeated surgery and an atopic disposition. Little is known about children operated on in the first year of life for reasons other than spina bifida. METHODS: Eighty-six patients (mean age, 10.2 years) with gastrointestinal or urologic surgery were investigated for the number, type, and date of surgical interventions. Additionally, skin prick tests and provocation tests were performed to classify sensitized and symptomatic latex-allergic individuals. RESULTS: Twenty-seven patients were regarded as sensitized to latex (31.4%). Twenty patients were classified as being atopic (25.6%). Atopic patients were significantly more often sensitized and provocation positive compared with nonsensitized and provocation-negative ones (P <.01). Children already operated on in the first year of life (n = 44) with a positive provocation showed significantly higher latex-specific IgE-values than individuals with a negative outcome (P <.0001). The total number of operations and degree of sensitization showed a significant correlation; more than 8 surgical interventions during the first year of life significantly increased the risk of clinically relevant allergy to latex. CONCLUSION: This study emphasizes that individuals undergoing surgical interventions during infancy should be handled latex free from the very beginning of life.

Hev b 8, the Hevea brasiliensis latex profilin, is a cross-reactive allergen of latex, plant foods and pollen.

BACKGROUND: Plant profilins are important pan-allergens. They are responsible for a significant percentage of pollen-related allergies. Limited information is available about their involvement in the latex-fruit syndrome and the cross-reactivities between latex and pollen. We aimed to clone and express the Hevea brasiliensis latex profilin to investigate its allergological significance and serological cross-reactivities to profilins from plant foods and pollens. METHODS: A DNA complementary to messenger RNA (cDNA) coding for the Hevea latex profilin, Hev b 8, was amplified by polymerase chain reaction from latex RNA. Recombinant (r)Hev b 8 was produced in Escherichia coli and used to screen sera from 50 latex- allergic health care workers (HCWs) with well-documented histories of food and pollen allergy and 34 latex-allergic spina bifida (SB) patients. The cross-reactivity of natural Hev b 8 and rHev b 8 with other plant profilins was determined by ELISA inhibition assays. A three-dimensional homology model of Hev b 8 was constructed based on known profilin structures. RESULTS: The cDNA of Hev b 8 encoded a protein of 131 amino acids with a predicted molecular mass of 14 kD. Twelve of the 50 HCWs and 2 of the 34 SB patients were sensitized to Hev b 8. All Hev b 8-sensitized patients showed allergic symptoms to pollen or plant foods. Cross-reactivities between profilins of latex, pollen and plant food were illustrated by their ability to inhibit IgE binding to rHev b 8. Homology modeling of Hev b 8 yielded a structure highly similar to Bet v 2, the birch pollen profilin, with the most distinct differences located at the N-terminus. CONCLUSIONS: We conclude that primary sensitization to latex profilin in the majority of cases takes place via pollen or food profilins. Additionally, pollinosis and food-allergic patients with profilin-specific IgE can be at risk of developing latex allergy.

Latex hypersensitivity in spinal cord injured adult patients.

Latex hypersensitivity is a major cause of anaphylaxis during anaesthesia. Patients with spina bifida, health care or rubber industry workers have been considered at risk for latex sensitization. By analogy, the existence of other at-risk subsets of patients with latex exposure due to frequent surgical procedures has been suggested. The aim of this study was to evaluate the prevalence of latex sensitization in a cohort of adult patients with spinal cord injury and repeated latex exposure. Forty-two adult patients with spinal cord injury were studied and retrospectively compared to a group of 30 children with spina bifida evaluated using a similar protocol. Patients were administered a questionnaire concerning history of latex hypersensitivity, atopy, and surgical procedures. Latex sensitivity was investigated by skin prick-tests and latex-specific IgE assay. The search for atopy was based on in vivo and in vitro tests against a panel of environmental allergens. No chronic spinal cord injured patient had a history of latex allergy. When compared with spina bifida, the number of surgical procedures was not statistically different. Although not significantly different, the prevalence of atopy was higher in spina bifida patients. The high level of latex sensitization in spina bifida patients contrasted sharply with the absence of sensitization observed on both skin and in vitro tests in patients with spinal cord injury (P<0.0001). This study confirms that adult patients with chronic neurologic defects resulting from spinal cord injury exhibit a low risk of latex sensitization. These results suggest that considering adult patients with repeated surgical procedures as a group at risk for latex sensitization because of a high degree of latex exposure should be re-examined.

Recombinant Hev b 1: large-scale production and immunological characterization.

BACKGROUND: Hev b 1 represents one of the most important allergens in Hevea brasiliensis latex. It is difficult to get an appropriate amount of native Hev b 1 (nHev b 1) for research purposes. OBJECTIVE: The aim of this study was to produce sufficient amounts of Hev b 1 by recombinant methods to prove its suitability for latex allergy diagnostics. METHODS: We isolated total RNA of Hevea brasiliensis leaves and synthesized cDNA by RT PCR. Recombinant Hev b 1 (rHev b 1) as well as three fragments (amino acid residues 29-137, 48-137, 78-137) were subcloned and expressed as fusion proteins with Maltose-binding protein (MBP) in Escherichia coli. The MBP-rHev b 1 fusion protein was examined by RAST with the CAP method, histamine release test and immunoblots with human sera from spina bifida patients as well as from health care workers with latex allergy and monoclonal antibodies. RESULTS: Histamine release test and immunoblots revealed the high allergenicity of the MBP-rHev b 1 construct. By the CAP method, 54 out of 58 serum samples (93%) from latex-sensitized spina bifida patients previously showing immunoglobulin (Ig) E to nHev b 1 exhibited IgE-binding to rHev b 1. Among 71 latex-allergic health care workers tested, 16 (22.5%) had IgE antibodies to rHev b 1. The analysis of the fusion proteins carrying rHev b 1 fragments revealed that the loss of the N-terminal 28 amino acid residues did not affect IgE-binding. In contrast, the lack of the first 47 amino acid residues led to decreased IgE-binding reactivity in two out of four sera tested, whereas the absence of the N-terminal 77 residues abolished IgE-binding in these two sera. CONCLUSION: The MBP-rHev b 1 fusion protein exhibits a corresponding IgE-binding reactivity to nHev b 1 and may therefore substitute natural Hev b 1 for both in vitro diagnostics and research purposes.