Immunophenotypic predictors of influenza vaccine immunogenicity in pediatric hematopoietic cell transplant recipients

ABSTRACT

Pediatric hematopoietic cell transplant (HCT) recipients exhibit poor serologic responses to influenza vaccination early after transplant. To facilitate the optimization of influenza vaccination timing, we sought to identify B- and T-cell subpopulations associated with influenza vaccine immunogenicity in this population. We used mass cytometry to phenotype peripheral blood mononuclear cells collected from pediatric HCT recipients enrolled in a multicenter influenza vaccine trial comparing high- and standard-dose formulations over 3 influenza seasons (2016-2019). We fit linear regression models to estimate relationships between immune cell subpopulation numbers before vaccination and prevaccination to postvaccination geometric mean fold rises in antigen-specific (A/H3N2, A/H1N1, and B/Victoria) serum hemagglutination inhibition antibody titers (28-42 days, and ∼6 months after 2 doses). For cell subpopulations identified as predictive of a response to all 3 antigens, we conducted a sensitivity analysis including time after transplant as an additional covariate. Among 156 HCT recipients, we identified 33 distinct immune cell subpopulations; 7 significantly predicted responses to all 3 antigens 28 to 42 days after a 2-dose vaccine series, irrespective of vaccine dose. We also found evidence that baseline absolute numbers of naïve B cells, naïve CD4+ T cells, and circulating T follicular helper cells predicted peak and sustained vaccine-induced titers irrespective of dose or timing of posttransplant vaccine administration. In conclusion, several B- and T-cell subpopulations predicted influenza vaccine immunogenicity in pediatric HCT recipients. This study provides insights into the immune determinants of vaccine responses and may help guide the development of tailored vaccination strategies for this vulnerable population.

Maternal Vaccine Effectiveness Against Influenza-Associated Hospitalizations and Emergency Department Visits in Infants

Importance

Influenza virus infection during pregnancy is associated with severe maternal disease and may be associated with adverse birth outcomes. Inactivated influenza vaccine during pregnancy is safe and effective and can protect young infants, but recent evidence, particularly after the 2009 novel influenza A (H1N1) pandemic, is limited.

Objective

To evaluate the effectiveness of influenza vaccination during pregnancy against laboratory-confirmed influenza-associated hospitalizations and emergency department (ED) visits in infants younger than 6 months.

Design, Setting, and Participants

This was a prospective, test-negative case-control study using data from the New Vaccine Surveillance Network from the 2016 to 2017 through 2019 to 2020 influenza seasons. Infants younger than 6 months with an ED visit or hospitalization for acute respiratory illness were included from 7 pediatric medical institutions in US cities. Control infants with an influenza-negative molecular test were included for comparison. Data were analyzed from June 2022 to September 2023.

Exposure

Maternal influenza vaccination during pregnancy.

Main Outcomes and Measures

We estimated maternal vaccine effectiveness against hospitalizations or ED visits in infants younger than 6 months, those younger than 3 months, and by trimester of vaccination. Maternal vaccination status was determined using immunization information systems, medical records, or self-report. Vaccine effectiveness was estimated by comparing the odds of maternal influenza vaccination 14 days or more before delivery in infants with influenza vs those without.

Results

Of 3764 infants (223 with influenza and 3541 control infants), 2007 (53%) were born to mothers who were vaccinated during pregnancy. Overall vaccine effectiveness in infants was 34% (95% CI, 12 to 50), 39% (95% CI, 12 to 58) against influenza-associated hospitalizations, and 19% (95% CI, -24 to 48) against ED visits. Among infants younger than 3 months, effectiveness was 53% (95% CI, 30 to 68). Effectiveness was 52% (95% CI, 30 to 68) among infants with mothers who were vaccinated during the third trimester and 17% (95% CI, -15 to 40) among those with mothers who were vaccinated during the first or second trimesters.

Conclusions and Relevance

Maternal vaccination was associated with reduced odds of influenza-associated hospitalizations and ED visits in infants younger than 6 months. Effectiveness was greatest among infants younger than 3 months, for those born to mothers vaccinated during the third trimester, and against influenza-associated hospitalizations.

Evaluation of BNT162b2 Covid-19 Vaccine in Children Younger than 5 Years of Age

BACKGROUND

Safe and effective vaccines against coronavirus disease 2019 (Covid-19) are urgently needed in young children.

METHODS

We conducted a phase 1 dose-finding study and are conducting an ongoing phase 2-3 safety, immunogenicity, and efficacy trial of the BNT162b2 vaccine in healthy children 6 months to 11 years of age. We present results for children 6 months to less than 2 years of age and those 2 to 4 years of age through the data-cutoff dates (April 29, 2022, for safety and immunogenicity and June 17, 2022, for efficacy). In the phase 2-3 trial, participants were randomly assigned (in a 2:1 ratio) to receive two 3-μg doses of BNT162b2 or placebo. On the basis of preliminary immunogenicity results, a third 3-μg dose (≥8 weeks after dose 2) was administered starting in January 2022, which coincided with the emergence of the B.1.1.529 (omicron) variant. Immune responses at 1 month after doses 2 and 3 in children 6 months to less than 2 years of age and those 2 to 4 years of age were immunologically bridged to responses after dose 2 in persons 16 to 25 years of age who received 30 μg of BNT162b2 in the pivotal trial.

RESULTS

During the phase 1 dose-finding study, two doses of BNT162b2 were administered 21 days apart to 16 children 6 months to less than 2 years of age (3-μg dose) and 48 children 2 to 4 years of age (3-μg or 10-μg dose). The 3-μg dose level was selected for the phase 2-3 trial; 1178 children 6 months to less than 2 years of age and 1835 children 2 to 4 years of age received BNT162b2, and 598 and 915, respectively, received placebo. Immunobridging success criteria for the geometric mean ratio and seroresponse at 1 month after dose 3 were met in both age groups. BNT162b2 reactogenicity events were mostly mild to moderate, with no grade 4 events. Low, similar incidences of fever were reported after receipt of BNT162b2 (7% among children 6 months to <2 years of age and 5% among those 2 to 4 years of age) and placebo (6 to 7% among children 6 months to <2 years of age and 4 to 5% among those 2 to 4 years of age). The observed overall vaccine efficacy against symptomatic Covid-19 in children 6 months to 4 years of age was 73.2% (95% confidence interval, 43.8 to 87.6) from 7 days after dose 3 (on the basis of 34 cases).

CONCLUSIONS

A three-dose primary series of 3-μg BNT162b2 was safe, immunogenic, and efficacious in children 6 months to 4 years of age. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04816643.).

Evaluation of the BNT162b2 Covid-19 Vaccine in Children 5 to 11 Years of Age

BACKGROUND

Safe, effective vaccines against coronavirus disease 2019 (Covid-19) are urgently needed in children younger than 12 years of age.

METHODS

A phase 1, dose-finding study and an ongoing phase 2-3 randomized trial are being conducted to investigate the safety, immunogenicity, and efficacy of two doses of the BNT162b2 vaccine administered 21 days apart in children 6 months to 11 years of age. We present results for 5-to-11-year-old children. In the phase 2-3 trial, participants were randomly assigned in a 2:1 ratio to receive two doses of either the BNT162b2 vaccine at the dose level identified during the open-label phase 1 study or placebo. Immune responses 1 month after the second dose of BNT162b2 were immunologically bridged to those in 16-to-25-year-olds from the pivotal trial of two 30-μg doses of BNT162b2. Vaccine efficacy against Covid-19 at 7 days or more after the second dose was assessed.

RESULTS

During the phase 1 study, a total of 48 children 5 to 11 years of age received 10 μg, 20 μg, or 30 μg of the BNT162b2 vaccine (16 children at each dose level). On the basis of reactogenicity and immunogenicity, a dose level of 10 μg was selected for further study. In the phase 2-3 trial, a total of 2268 children were randomly assigned to receive the BNT162b2 vaccine (1517 children) or placebo (751 children). At data cutoff, the median follow-up was 2.3 months. In the 5-to-11-year-olds, as in other age groups, the BNT162b2 vaccine had a favorable safety profile. No vaccine-related serious adverse events were noted. One month after the second dose, the geometric mean ratio of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing titers in 5-to-11-year-olds to those in 16-to-25-year-olds was 1.04 (95% confidence interval [CI], 0.93 to 1.18), a ratio meeting the prespecified immunogenicity success criterion (lower bound of two-sided 95% CI, >0.67; geometric mean ratio point estimate, ≥0.8). Covid-19 with onset 7 days or more after the second dose was reported in three recipients of the BNT162b2 vaccine and in 16 placebo recipients (vaccine efficacy, 90.7%; 95% CI, 67.7 to 98.3).

CONCLUSIONS

A Covid-19 vaccination regimen consisting of two 10-μg doses of BNT162b2 administered 21 days apart was found to be safe, immunogenic, and efficacious in children 5 to 11 years of age. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04816643.).

Caregiver rating of early childhood development: Reliability and validity of the ASQ-3 in rural Guatemala

BACKGROUND

Although performance-based assessment of early childhood development is preferred, there are a number of limitations to this methodology in low resource settings (LRSs). Hence, clinicians and researchers often rely on caregiver report screening tools. The Ages and Stages Questionnaire 3 (ASQ) is one of the most widely used caregiver report measures globally. Adequate psychometric properties have been demonstrated in high income settings, especially when used in older children, high- risk children, or those with severe neurodevelopmental delays. However, its utility is more variable within very young children and for use in LRSs.

METHODS

The reliability and validity of the ASQ was determined for children ages 0-5 years living in rural Guatemala. Internal consistency and test-retest reliability were assessed, as well as concurrent and predictive validity. Sensitivity, specificity, positive and negative predictive values related to performance-based developmental assessment (Mullen Scales of Early Learning; MSEL) and growth status (i.e. stunting) were also calculated.

RESULTS

Internal consistency reliability for the ASQ was adequate, except when results were limited by small sample size. Test-retest reliability ranged from low to moderate (r = 0.08-0.43; p < 0.05-0.01). However, there was significant variability in mean scores over time across ASQ domain scores. In terms of validity, the ASQ did not discriminate adequately between children who performed within or below age-expectations on performance-based developmental testing or those with and without stunting.

CONCLUSIONS

The ASQ did not demonstrate adequate psychometric properties in rural Guatemala, consistent with concerns documented in other LRSs. These results indicate that existing caregiver report screening measures of early childhood development should be utilized with caution in LRSs, and alternative methods for assessment or in the development and utilization of caregiver report measures should be considered.

Antenatal care service delivery and factors affecting effective tetanus vaccine coverage in low- and middle-income countries: Results of the Maternal Immunisation and Antenatal Care Situational analysis (MIACSA) project

Objectives

To map the integration of existing maternal tetanus immunization programmes within antenatal care (ANC) services for pregnant women in low- and middle-income countries (LMICs) and to identify and understand the challenges, barriers and facilitators associated with high performance maternal vaccine service delivery.

Design

A mixed methods, cross sectional study with four data collection phases including a desk review, online survey, telephone and face-to-face interviews and in country visits was undertaken between 2016 and 2018. Associations of different service delivery process components with protection at birth (PAB) and with country groups were established. PAB was defined as the proportion of neonates protected at birth against neonatal tetanus. Regression analysis and structural equation modelling was used to assess associations of different variables with maternal tetanus immunization coverage. Latent class analysis (LCA), was used to group country performance for maternal immunization, and to address the problem of multicollinearity.

Setting

LMICs.

Results

The majority of LMICs had a policy on recommended number of ANC visits, however most were yet to implement the WHO guidelines recommending eight ANC contacts. Countries that recommended > 4 ANC contacts were more likely to have high PAB > 90%. Passive disease surveillance was the most common form of disease surveillance performed but the maternal and neonatal morbidity and mortality indicators recorded differed between countries. The presence of user fees for antenatal care and maternal immunization was significantly associated with lower PAB (<90%).

Conclusions

Recommendations include implementing the current WHO ANC guideline to facilitate increased opportunities for vaccination during each pregnancy. Improved utilisation of ANC services by increasing the demand side by increasing the quality of services, reducing any associated costs and supporting user fee exemptions, or the supply side can also enhance utilisation of ANC services which are positioned as an ideal platform for delivery of maternal vaccines.

Dengue Virus and Yellow Fever Virus Detection Using Reverse Transcription-Insulated Isothermal PCR and Comparison with Real-Time RT-PCR

Real-time reverse transcriptase PCR (rRT-PCR) is the most accurate method for the detection of dengue virus (DENV) and yellow fever virus (YFV) in acute illness. However, performing rRT-PCR is not feasible for many laboratories in regions of endemicity. The current study compared new reverse transcription-insulated isothermal PCRs (the POCKIT DENV and YFV reagent sets) with laboratory-developed rRT-PCRs for both viruses using clinical samples and viral strains from different endemic regions. Sensitivity and specificity of the POCKIT DENV Reagent Set were 87.2% (68/78 samples) and 98.2% of samples (54/55), respectively. The YFV reagent set demonstrated sensitive detection of YFV RNA from six viral strains down to an estimated concentration of 2.5 log₁₀ copies/mL and proved to be specific for YFV. Although the POCKIT assays require RNA extraction, they may provide accurate and less-complex options for molecular testing in laboratory settings where rRT-PCR is not practical.

Reliability and Validity of an Adapted and Translated Version of the Mullen Scales of Early Learning (AT-MSEL) in Rural Guatemala

BACKGROUND

A growing literature base supports the use of tests developed in high-income countries to assess children in low resource settings when carefully translated, adapted, and applied. Evaluation of psychometric properties of adapted and translated measures within populations is necessary. The current project sought to evaluate the reliability and validity of an adapted and translated version of the Mullen Scales of Early Learning (AT-MSEL) in rural Guatelama.

METHODS

The reliability and validity of the AT-MSEL in rural Guatemala were analyzed for children ages 0-5 years.

RESULTS

Interrater reliability coefficients (ICC = 0.99-1.0) and internal consistency (Cronbach's alpha = 0.91-0.93) were excellent for all subscales. General linear models utilizing paired data showed consistency between standard scores (p < 0.0001). Mean raw scores increased with chronological age, as expected. Across age groups, subscales were significantly, positively correlated with one another (p < 0.05 - < 0.001) with one exception, visual reception and expressive language at the 0-10 month age range (p = 0.43).

CONCLUSIONS

The AT- MSEL showed strong psychometric properties in a sample of young children in rural Guatemala. Findings demonstrate that the AT-MSEL can be used validly and reliably within this specific population of children. This work supports the concept that tests developed in high-income countries can be used to assess children in low resource settings when carefully translated, adapted and applied.

Performance of Young Children in Rural Guatemala on the Mullen Scales of Early Learning

Objective

The literature supports using tests developed in high-income countries to assess children in low and lower-middle income countries (LMICs) when carefully translated, adapted, and applied (Holding et al., 2018; Mitchell et al., 2017). Research has shown the Mullen Scales of Early Learning (MSEL) to have adequate validity and sensitivity when used in LMICs (Bangirana et al., 2014; Koura et al., 2013), as well as equivalency to the American normative sample in lower risk populations (Bornman et al., 2010). Here, we describe the pattern of MSEL results in rural Guatemala.

Participants and Method

Children (n = 842; M enrollment age = 15.9 months; range 0-5 years) enrolled in an observational study of postnatal Zika exposure in rural Guatemala were administered an adapted and translated version of the MSEL (Connery et al., in press). To date, 352 children completed one, 393 children completed two, and 97 children completed three MSELs, for a total of 1,429 administrations.

Results

MSEL composite scores were similar to the American normative sample in children &lt;12 months (M = 93.3, SD = 11.1), but lower for children ages 1-5 years (mean = 71.1, SD = 15.1, p &lt; 0.0001). Moreover, lower scores were observed in children ages 1-5 years for all MSEL subscales, with the largest differences observed in receptive language (&lt;12 years: mean = 47.8, SD = 7.1; 1-5 years: mean = 35.1, SD = 10.0, p &lt; 0.0001).

Conclusions

Results are consistent with research that demonstrates a widening gap in test performance over time between children from higher and lower risk communities (Fernald et al., 2011; Paxson et al., 2005; Schady et al., 2015). Although findings are not meant to diagnose individual children, they highlight population changes in neurodevelopmental skills and the need for a better understanding of developmental patterns in LMICs. Future analyses will evaluate the impact of developmental risk factors over time and the performance of the MSEL in this population.

References

Bangirana, P., Opoka, R. O., Boivin, M. J., Idro, R., Hodges, J. S., Romero, R. A., … John, C. C. (2014). Severe Malarial Anemia is Associated With Long-term Neurocognitive Impairment. Clinical Infectious Diseases, 59(3), 336–344. https://doi.org/10.1093/cid/ciu293. Bornman, J., Sevcik, R. A., Romski, M., & Pae, H. K. (2010). Successfully Translating Language and Culture when Adapting Assessment Measures, ppi_254 111.118. Retrieved from https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1741-1130.2010.00254.x. Fernald, L. C. H., Weber, A., Galasso, E., & Ratsifandrihamanana, L. (2011). Socioeconomic gradients and child development in a very low income population: Evidence from Madagascar. Developmental Science, 14(4), 832–847. https://doi.org/10.1111/j.1467-7687.2010.01032.x. Holding, P., Anum, A., van de Vijver, F. J. R., Vokhiwa, M., Bugase, N., Hossen, T., … Gomes, M. (2018). Can we measure cognitive constructs consistently within and across cultures? Evidence from a test battery in Bangladesh, Ghana, and Tanzania. Applied Neuropsychology: Child, 7(1), 1-13 https://doi.org/10.1080/21622965.2016.1206823. Koura, K. G., Boivin, M. J., Davidson, L. L., Ouédraogo, S., Zoumenou, R., Alao, M. J., … Bodeau-Livinec, F. (2013). Usefulness of child development assessments for low-resource settings in francophone Africa. Journal of Developmental and Behavioral Pediatrics : JDBP, 34(7), 486–93. https://doi.org/10.1097/DBP.0b013e31829d211c. Mitchell, J. M., Tomlinson, M., Bland, R. M., Houle, B., Stein, A., & Rochat, T. J. (2017). Confirmatory factor analysis of the Kaufman assessment battery in a sample of primary school-aged children in rural South Africa. South African Journal of Psychology, 1–19. https://doi.org/10.1177/0081246317741822. Paxson, C., Schady, N., Izquierdo, S., León, M., Lucio, R., Ponce, J., … Hall, W. (2005). Cognitive Development among Young Children in Ecuador The Roles of Wealth, Health, and Parenting. Retrieved from http://econ.worldbank.org. Schady, N., Behrman, J., Araujo, M. C., Azuero, R., Bernal, R., Bravo, D., … Vakis, R. (2015). Wealth gradients in early childhood cognitive development in five Latin American countries. The Journal of Human Resources, 50(2), 446–463. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/25983344.

Maternal Immunization and Antenatal Care Situation Analysis (MIACSA) study protocol: a multiregional, cross-sectional analysis of maternal immunization delivery strategies to reduce maternal and neonatal morbidity and mortality

INTRODUCTION

Maternal immunization (MI) with tetanus toxoid containing vaccine, is a safe and cost-effective way of preventing neonatal tetanus. Given the prospect of introducing new maternal vaccines in the near future, it is essential to identify and understand current policies, practices and unmet needs for introducing and/or scaling up MI in low-income and middle-income countries (LMICs).

METHODS AND ANALYSIS

The Maternal Immunization and Antenatal Care Situation Analysis (MIACSA) is a mixed methods, cross-sectional study that will collect data in four phases: (1) a review of global databases for selected health indicators in 136 LMICs; (2) a structured online survey directed at Maternal, Newborn and Child Health and Expanded Programme on Immunization focal points in all 136 LMICs; (3) semistructured telephone interviews of 30 selected LMICs and (4) 10 week-long country visits, including key informant interviews, health facility visits and focus group discussions. The principal analyses will assess correlations between the various aspects of MI delivery strategies and proxy measures of health systems performance related to vaccine-preventable disease control. The primary outcome will be a typology of existing MI delivery models, and secondary outcomes will include country profiles of child and maternal health indicators, and a MI gaps and needs analysis.

ETHICS AND DISSEMINATION

The protocol was approved by the WHO Ethics Review Committee (ERC.0002908). The results will be made available in a project report and submitted for publication in peer-reviewed journals that will be shared broadly among global health decision-makers, researchers, product developers and country-level stakeholders.

Clinical Manifestations and Bacterial Genomic Analysis of Group A Streptococcus Strains That Cause Pediatric Toxic Shock Syndrome

We report here 18 cases of pediatric group A streptococcal toxic shock syndrome, associated clinical findings, and bacterial molecular genetic characteristics discovered through whole-genome sequencing. This comparative whole-genome sequencing revealed unique gene content (speK) and polymorphisms (dpiB) in emm87 group A Streptococcus, the relative contributions of which, in combination with the host response, in the development of streptococcal toxic shock syndrome remain to be elucidated.

Immunization in pregnancy clinical research in low- and middle-income countries - Study design, regulatory and safety considerations

Immunization of pregnant women is a promising public health strategy to reduce morbidity and mortality among both the mothers and their infants. Establishing safety and efficacy of vaccines generally uses a hybrid design between a conventional interventional study and an observational study that requires enrolling thousands of study participants to detect an unknown number of uncommon events. Historically, enrollment of pregnant women in clinical research studies encountered many barriers based on risk aversion, lack of knowledge, and regulatory ambiguity. Conducting research enrolling pregnant women in low- and middle-income countries can have additional factors to address such as limited availability of baseline epidemiologic data on disease burden and maternal and neonatal outcomes during and after pregnancy; challenges in recruiting and retaining pregnant women in research studies, variability in applying and interpreting assessment methods, and variability in locally acceptable and available infrastructure. Some measures to address these challenges include adjustment of study design, tailoring recruitment, consent process, retention strategies, operational and logistical processes, and the use of definitions and data collection methods that will align with efforts globally.

Neonatal death: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data

More than 40% of all deaths in children under 5 years of age occur during the neonatal period: the first month of life. Immunization of pregnant women has proven beneficial to both mother and infant by decreasing morbidity and mortality. With an increasing number of immunization trials being conducted in pregnant women, as well as roll-out of recommended vaccines to pregnant women, there is a need to clarify details of a neonatal death. This manuscript defines levels of certainty of a neonatal death, related to the viability of the neonate, who confirmed the death, and the timing of the death during the neonatal period and in relation to immunization of the mother.

Neonatal death: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data

More than 40% of all deaths in children under 5 years of age occur during the neonatal period: the first month of life. Immunization of pregnant women has proven beneficial to both mother and infant by decreasing morbidity and mortality. With an increasing number of immunization trials being conducted in pregnant women, as well as roll-out of recommended vaccines to pregnant women, there is a need to clarify details of a neonatal death. This manuscript defines levels of certainty of a neonatal death, related to the viability of the neonate, who confirmed the death, and the timing of the death during the neonatal period and in relation to immunization of the mother.

Global alignment of immunization safety assessment in pregnancy - The GAIA project

Immunization in pregnancy provides a promising contribution to globally reducing neonatal and under-five childhood mortality and morbidity. Thorough assessment of benefits and risks for the primarily healthy pregnant women and their unborn babies is required. The GAIA project was formed in response to the call of the World Health Organization for a globally concerted approach to actively monitor the safety of vaccines and immunization in pregnancy programs. GAIA aims to improve the quality of outcome data from clinical vaccine trials in pregnant women with a specific focus on the needs and requirements for safety monitoring in LMIC. In the first year of the project, a large and functional network of experts was created. The first outputs include a guidance document for clinical trials of immunization in pregnancy, a basic data collection guide, ten case definitions of key obstetric and neonatal health outcomes, an ontology of key terms and a map of pertinent disease codes. The GAIA Network is designed as an open and growing forum for professionals sharing the GAIA vision and aim. Based on the initial achievements, tools and services are developed to support investigators and strengthen immunization in pregnancy programs with specific focus on LMIC.

A new generation of bio-derived ceramic materials for medical applications

A new generation of bio-derived ceramics can be developed as a base material for medical implants. Specific plant species are used as templates on which innovative transformation processes can modify the chemical composition maintaining the original biostructure. Building on the outstanding mechanical properties of the starting lignocellulosic templates, it is possible to develop lightweight and high-strength scaffolds for bone substitution. In vitro and in vivo experiments demonstrate the excellent biocompatibility of this new silicon carbide material (bioSiC) and how it gets colonized by the hosting bone tissue because of its unique interconnected hierarchic porosity, which opens the door to new biomedical applications.

A comparison of the methods used to determine chewing preference

For much human activity there exists a 'lateral preference', that is a tendency to use one side of the body or the other; with respect to the hands for example, the vast majority of individuals have a preference for either the right or left hand. Most experts agree that mastication is no exception in that there is a 'preferred chewing side' but the determination of this preference is somewhat complex. This research analyses the mastication of 60 healthy subjects by means of preferred chewing side or 'PCS' tests, the Kazazoglu test, and kinesiography (KGF). While some authors consider the PCS to be the side which first comes into contact with the food we prefer to define it as the side on which the majority of the cycles analysed and registered take place. The objective of this research was to analyse the relationship that might exist between the two different methods used for determining a lateral chewing preference. Although there was no statistically significant agreement between the two techniques, both reflected the fact that there was a marked preference for the right hand side.

Tuberculosis among adult visitors of children with suspected tuberculosis and employees at a children's hospital

OBJECTIVE

Few children with tuberculosis (TB) have communicable disease, and most do not require isolation within the hospital. However, parents or adult visitors with unrecognized pulmonary TB may be a threat to hospital staff and other patients. We prospectively evaluated adults accompanying children hospitalized for suspected TB at a children's hospital to determine the frequency of undiagnosed, potentially contagious disease.

METHODS

From 1992 to 1998, chest radiographs were obtained from adult caretakers accompanying 59 consecutive children admitted to Texas Children's Hospital with suspected TB. A child and his or her family were placed under Airborne Precautions only if the child or the accompanying adult exhibited characteristics of potentially contagious disease. Annual rates of tuberculin skin test conversion in hospital employees were obtained for the same period.

RESULTS

Of the 105 screened adults, 16 (15%) had previously undetected pulmonary TB. These adults were associated with 14 (24%) of the 59 children. In all instances in which the adult was the patient's parent, he or she was the source of infection to the child. Only 8 (13.5%) of the 59 children required isolation. Tuberculin skin test conversion from a negative to a positive reaction occurred in 127 employees (8 per 1,000 employee-years at risk). Only 4 of these 127 employees performed activities involving direct patient contact. None was in contact with families with a known potentially contagious adult or pediatric patient.

CONCLUSIONS

The risk of infection of healthcare workers from pediatric patients with primary TB appeared to be minimal, and most children with TB did not need isolation. Infection control efforts should be focused on accompanying adults and adult visitors.

Validity of specific IgE antibodies in children with egg allergy

BACKGROUND

The demonstration of specific IgE antibodies to egg supports the existence of allergy to this food, but a correct diagnosis can only be obtained after a challenge test. Several studies have assessed different cut-off points in the level of these antibodies as predictors of clinical reactivity.

OBJECTIVE

Validation of the specific IgE antibodies measured by the CAP System Fluorescence enzyme immunoassay (FEIA) technique in the diagnosis of egg allergy in children under 2 years of age.

METHODS

A prospective study of 81 children with suspected egg allergy was performed. Specific IgE antibodies was quantified for egg white, egg yolk, ovoalbumin and ovomucoid. The diagnostic challenge test was carried out following the previously established criteria. The validity of the specific IgE antibodies was analysed using children with a negative diagnostic challenge test as control group.

RESULTS

The prevalence of egg allergy in the group studied was 79% and egg white was the allergen that showed the greatest diagnostic efficacy. The sensitivity and positive predictive value of the prick test and of the CAP to egg white were excellent and the specificity and the negative predictive value had lower values. A level of > or = 0.35 KU(A)/L for specific IgE antibodies to egg white predicted the existence of reaction in 94% of the cases.

CONCLUSIONS

Quantification of the specific IgE antibodies to egg white is useful in the diagnosis of egg allergy. In children under 2 years of age with a background of immediate hypersensitivity after egg ingestion and presence of specific IgE antibodies to egg white of > or = 0.35 KU(A)/L, diagnostic challenge test is not necessary to establish the diagnosis of allergy to this food.

Ischaemia induces changes in the association of the binding protein 4E-BP1 and eukaryotic initiation factor (eIF) 4G to eIF4E in differentiated PC12 cells

Ischaemia was obtained in vitro by subjecting nerve-growth-factor-differentiated PC12 cells to glucose deprivation plus anoxia. During ischaemia the rate of protein synthesis was significantly inhibited, and eIF4E-binding protein (4E-BP1) and eukaryotic initiation factor 4E (eIF4E) were significantly dephosphorylated in parallel. In addition, ischaemia induced an enhancement of the association of 4E-BP1 to eIF4E, which in turn decreased eIF4F formation, whereas no degradation of initiation factor 4G was observed. The treatment of PC12 cells with the specific p38 mitogen-activated protein kinase inhibitor SB203580 induced eIF4E dephosphorylation but did not cause any effect on protein synthesis rate. Rapamycin, the inhibitor of mammalian target of rapamycin ('mTOR'), but not PD98059, the inhibitor of extracellular signal-regulated protein kinases ('ERK1/2'), induced similar effects on 4E-BP1 phosphorylation to ischaemia; nevertheless, 4E-BP1-eIF4E complex levels were higher in ischaemia than in rapamycin-treated cells. In addition, both protein synthesis rate and eIF4F formation were lower in ischaemic cells than in rapamycin-treated cells.

Allergic reactions associated with airborne fish particles in IgE-mediated fish hypersensitive patients

We evaluated the clinical characteristics found in 21 children who showed allergic reactions upon incidental inhalation of fish odors or fumes, from 197 diagnosed with IgE-mediated fish hypersensitivity. Allergic reactions to fish via ingestion began in most patients (86%) within the first 24 months of life. The vast majority (19/21) of patients showed cutaneous symptoms, either alone or, less frequently, associated with other clinical manifestations. Hake and flounder were the species of fish most frequently implicated in eliciting clinical manifestations upon ingestion. After diagnosis, all these patients were placed on a strict fish-avoidance diet. During this period of avoidance, patients reported allergic reactions (mean age 7 years) after incidental exposure to airborne fish odors or fumes. Clinical manifestations through inhalation were respiratory (mainly wheezing) in 12 patients and cutaneous (mainly urticaria) in nine patients. Nineteen of 21 patients reported three or more episodes upon exposure to fish aerosols; in most cases, these episodes occurred at home when other people were eating fish. In conclusion, incidental inhalation of fish odors or fumes could play an important role in accidental and unknown encounters with fish in children on fish-avoidance diets for fish IgE-mediated hypersensitivity. Such exposures could elicit clinical symptoms and could have some effect in delaying the development of tolerance.