Reference Values For Healthy Children Research Articles

Histological analysis of the medial gastrocnemius muscle in young healthy children.

Introduction: Histological data on muscle fiber size and proportion in (very) young typically developing (TD) children is not well documented and data on capillarization and satellite cell content are also lacking. Aims: This study investigated the microscopic properties of the medial gastrocnemius muscle in growing TD children, grouped according to age and gender to provide normal reference values in healthy children. Methods: Microbiopsies of the medial gastrocnemius (MG) muscle were collected in 46 TD boys and girls aged 2-10years subdivided into 4 age groups (2-4, 4-6, 6-8 and 8-10years). Sections were immunostained to assess fiber type cross-sectional area (fCSA) and proportion, the number of satellite cells (SC), capillary to fiber ratio (C/F), capillary density for type I and II fiber (CFD), capillary domain, capillary-to-fiber perimeter exchange index (CFPE) and heterogeneity index. fCSA was normalized to fibula length2 and the coefficient of variation (CV) was calculated to reflect fCSA intrasubject variability. Results: Absolute fCSA of all fibers increased with age (r = 0.72, p < 0.001) but more in boys (+112%, p < 0.05) than in girls (+48%, p > 0.05) Normalized fCSA, CV and fiber proportion did not differ between age groups and gender. C/F was strongly correlated with age in boys (r = 0.83, p < 0.001), and to a lesser extent in girls (r = 0.37, p = 0.115), while other capillary parameters as well as the number of SC remained stable with increasing age in boys and girls. Discussion: This study provides reference values of histological measures in MG according to age in normally growing boys and girls. These data may be used as a reference to determine disease impact and efficacy of therapeutic approach on the muscle.

Reference values in healthy children using the Quantra Hemostasis Analyzer, a novel point of care viscoelastic testing device.

Reference values in healthy children using the Quantra Hemostasis Analyzer, a novel point of care viscoelastic testing device.

Immunological imbalance in microcephalic children with congenital Zika virus syndrome.

Microcephalic children due congenital Zika virus syndrome (CZS) present neurological symptoms already well described. However, several other alterations can also be observed. Here, we aimed to evaluate the immune system of microcephaly CZS children. We showed that these patients have enlarged thymus, spleen and cervical lymph nodes, analysed by ultrasound and compared to the reference values for healthy children. In the periphery, they have an increase in eosinophil count and morphological alterations as hypersegmented neutrophils and atypical lymphocytes, even in the absence of urinary tract infections, parasitological infections or other current symptomatic infections. Microcephalic children due CZS also have high levels of IFN-γ, IL-2, IL-4, IL-5 and type I IFNs, compared to healthy controls. In addition, this population showed a deficient cellular immune memory as demonstrated by the low reactivity to the tuberculin skin test even though they had been vaccinated with BCG less than 2years before the challenge with the PPD. Together, our data demonstrate for the first time that CZS can cause alterations in primary and secondary lymphoid organs and also alters the morphology and functionality of the immune system cells, which broadens the spectrum of CZS symptoms. This knowledge may assist the development of specific therapeutic and more efficient vaccination schemes for this population of patients.

HbA1c percentiles and the association between BMI, age, gender, puberty, and HbA1c levels in healthy German children and adolescents.

The measurement of glycated hemoglobin (HbA1c) represents one way to detect type 1 and 2 diabetes in children at an early stage. However, to date, variations in HbA1c levels are not fully understood, even in healthy children. With this in mind, the present study aimed to establish HbA1c reference values in healthy children and to investigate the influence of various independent variables. Two thousand four hundred fifty-five healthy children and adolescents aged between 0.5 and 18 years participated in the population-based cohort study LIFE Child, Germany. Age- and gender-dependent percentiles were estimated, enabling HbA1c values to be converted into standard deviation scores (SDS). Logistic regression models were applied to assess associations between HbA1c-SDS (as outcome) and age, gender, BMI, birth weight, physical activity, pubertal status, and socioeconomic status (SES; as explanatory variables). The mean HbA1c value was 31.79 mmol/mol or 5.06% (SD= 3.3 mmol/mol, SD= 0.3%). Positive associations with HbA1c values were identified for age (b= 0.09, p< 0.001), gender (b= 0.25, p= 0.007), and BMI-SDS (b= 0.06, p< 0.001). In addition, obesity was related to higher HbA1c values (b= 0.29, p< 0.001). Compared to prepuberty, the pubertal and postpubertal stages were associated with higher HbA1c levels. Furthermore, higher SES was associated with higher HbA1c-SDS (b= 0.01, p= 0.04). The present study established HbA1c reference values based on a large sample of healthy German children and adolescents. Age, gender, SES, pubertal stage, and BMI were found to be associated with higher HbA1c levels.

A meta-analysis of accelerometer sleep outcomes in healthy children based on the Sadeh algorithm: the influence of child and device characteristics.

Children often experience sleep problems, with a negative impact on mood, behavior, cognitive function, and other aspects of mental and physical health. Accelerometers are widely used to assess sleep, but general reference values for healthy children do not yet exist. The aim of this meta-analysis was to determine mean values for wake after sleep onset (WASO), sleep efficiency (SE), total sleep time (TST) and sleep onset latency (SOL), and to determine the effect of child and accelerometer-characteristics. A search included studies with healthy children, 0-18 years, reporting WASO, SE, TST, and/or SOL, calculated with the Sadeh algorithm. Meta-analyses with random effects produced pooled estimate means per outcome. Meta-regression analyses determined the effect of age, sex, placement site and accelerometer type. Eighty-three studies (9,068 participants) were included. Pooled means were 63 min (95% CI 57 to 69) for WASO, 88% (95% CI 87 to 89) for SE, 477 min (95% CI 464 to 491) for TST and 19 min (95% CI 17 to 22) for SOL. Heterogeneity was high (95%-99%). TST decreased with age and there was an age-effect on SOL. SE differed between wrist and ankle (used in age 0-24 months) placement, and between piezoelectric and MEMS-type accelerometers. No differences were found between boys and girls, although this number of studies was small. We found differences in almost all investigated outcomes and heterogeneity was high. Therefore, we advise to use a study-specific control sample until more robust reference values are available. Future research should narrow the methodological heterogeneity and produce larger datasets, needed to establish these reference values.

Normative data for multiple breath washout outcomes in school-aged Caucasian children.

The multiple breath nitrogen washout (N2MBW) technique is increasingly used to assess the degree of ventilation inhomogeneity in school-aged children with lung disease. However, reference values for healthy children are currently not available. The aim of this study was to generate reference values for N2MBW outcomes in a cohort of healthy Caucasian school-aged children. N2MBW data from healthy Caucasian school-age children between 6 and 18 years old were collected from four experienced centres. Measurements were performed using an ultrasonic flowmeter (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) and were analysed with commercial software (Spiroware version 3.2.1, Eco Medics AG). Normative values and upper limits of normal (ULN) were generated for lung clearance index (LCI) at 2.5% (LCI2.5%) and at 5% (LCI5%) of the initial nitrogen concentration and for moment ratios (M1/M0 and M2/M0). A prediction equation was generated for functional residual capacity (FRC). Analysis used 485 trials from 180 healthy Caucasian children aged from 6 to 18 years old. While LCI increased with age, this increase was negligible (0.04 units·year-1 for LCI2.5%) and therefore fixed ULN were defined for this age group. These limits were 7.91 for LCI2.5%, 5.73 for LCI5%, 1.75 for M1/M0 and 6.15 for M2/M0, respectively. Height and weight were found to be independent predictors of FRC. We report reference values for N2MBW outcomes measured on a commercially available ultrasonic flowmeter device (Exhalyzer D, Eco Medics AG) in healthy school-aged children to allow accurate interpretation of ventilation distribution outcomes and FRC in children with lung disease.

Interdialytic weight gain and vasculopathy in children on hemodialysis: a single center study.

Increased interdialytic weight gain (IDWG) has been associated with poor outcomes in adults, but its impact on hemodialysis vasculopathy in children is unknown. Nineteen patients (age 9 to 19years old) with a median hemodialysis duration of 10.4months were enrolled. Cardiovascular evaluation included left ventricular mass index (LVMI), pulse wave velocity (PWV), and carotid intima-media thickness (cIMT) measurements. PWV and cIMT were expressed as z-scores based on reference values in healthy children. Blood pressure (BP) evaluation consisted in a 24-h ambulatory BP monitoring. Mean IDGW and residual urine output during the 6months prior to cardiovascular examination were calculated. Increased cIMT, LVMI, and PWV was observed in 11 (57.9%), 7 (36.8%), and 5 (26.3%) patients respectively, while BP was normal in all patients. Median IDWG was 3.5% (1.8-6.7). Residual urine output and BP status did not significantly differ between patients with IDWG ≥ or < 4%. After linear regression, IDWG was correlated to cIMT z-score (r2 = 0.485, p = 0.001), but not to PWV z-score (r2 = 0.04, p = 0.415) and LVMI (r2 = 0.092, p = 0.206). After univariate logistic regression, IDWG ≥ 4% was significantly associated to increased cIMT (above 1.65 SDS) (odds ratio 12.25, 95% confidence interval 1.08-138.988). The trend toward an increased cIMT with IDWG ≥ 4% was observed in both patients with short and long dialysis vintage. High IDWG is associated with increased cIMT in hemodialyzed children independently of BP control and dialysis vintage. This observation reinforces the importance of interventions to avoid IDWG in hemodialyzed children.

Significant age- and gender-related variability of main lymphocyte subsets in paediatric patients: Latvian data.

Age- and gender-related variability of main lymphocyte subsets (T, B and NK cell absolute counts and percentages from Ly; T4, T8 and DN cell absolute counts and percentages from lymphocytes and from T cells; T4:T8 and T:B ratios) was studied in a large cohort of paediatric patients (2days-17years) at yearly intervals. A total of 4128 six-color TBNK tests performed on BD FACSCanto II flow cytometer were assessed; patients with immune deficiencies and tumours were not included. The study revealed significant age- and gender-related changes in all subsets. Absolute counts of T, B, T4 cells dropped from neonates to adolescents, decrease in T8 and NK cells was milder; relative count of T cells increased with age and that of B cells decreased; T4:T8 ratio went down and T:B ratio grew. Total T, T4 cells and T4:T8 ratio were significantly higher in girls, while T8, NK and DN cells were significantly higher in boys; significantly higher relative and absolute B cell counts in boys appeared in adolescence. We compared our results with reference values for healthy children (Tosato etal, Cytometry A. 2015;87:81); there was a good concordance, except for DN cells. Advantages of using patient cohort instead of healthy children as reference, possibilities for adjusting age- and gender-specific reference ranges and potential international data pooling are discussed.

Urinary exoglycosidases, reference values in healthy children

PurposeThe purpose of the study was to determine the effect of age on lysosomal exoglycosidase activities: α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase in healthy children and adolescents. Material and methodsUrine samples were collected from 203 healthy children and adolescents (girls = 99, boys = 104), aged six months to 17.9 years. The activities of α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase were determined by colorimetric method and expressed in pKat/μg of creatine (pKat/μg Cr.). ResultsUrinary α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase activities (pKat/μg Cr.) were the highest in children below 3 years of age in comparison to the remaining age groups. There was a statistically significant negative correlation between urinary α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase (pKat/μg Cr.) and age (r = −0.36; r = −0.36; r = −0.35; r = −0.35; at p < 0.0001, respectively). In addition, we constructed the reference values for urinary activity of α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase (pKat/μg Cr.) in percentiles according to age in 3-year intervals. ConclusionsOur study is the first to show reference values for urinary α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase in children and adolescents.

Predictive Formulas To Improve The Interpretation Of Cardiorespiratory Fitness In Children

Adequate reference values for cardiopulmonary exercise testing (CPET) is crucial for accurate interpretation and prognostic purposes for children with a chronic disease. Current reference values in healthy children have been developed using heterogeneous exercise protocols and often incomplete adjustment for body size. PURPOSE: To update current reference values from CPET and provide new reference values for several parameters previously unstudied in children using a prospectively recruited cohort of healthy children. METHODS: In this cross-sectional multicenter study, we prospectively recruited 269 healthy children (♂=107; ♀=162) between the ages of 12-17 years old (14.8 ± 1.5) in local schools. We measured height, weight, waist circumference, pubertal development and fat free mass (FFM) and performed a symptom-limited CPET (Vmax Encore Metabolic Cart, Sensormedic, San Diego, CA) on an electronically-braked ergocycle using a progressive ramp protocol. Reference values and Z score were computed by testing several regressions models for each CPET measurement. Variation around the predicted mean was modeled to account for heteroscedasticity and residual association with growth-related parameters was assessed. RESULTS: Using currently published reference values, up to 31.2% of children were classified as having abnormal CPET results despite being free of chronic disease. Our weighted non-linear parametric modeling allowed more precise and well-adjustted Z scores and percentiles limits. The table shows a selection of our predicting equations as well as the percentage of children below the 3rd percentile. Selection of prediction equations for malesTable: No title available.CONCLUSION: The use of weighted non-linear regression model resulted in a decreased false-positive rate. These updated and new reference values provide an accurate lower limit of normal thus improving their value for prognostic and risk-stratification in children with chronic diseases.

Cardiopulmonary Exercise Testing in Healthy Children

Background: Cardiopulmonary exercise testing is a valuable tool for assessing the clinical condition and prognosis of patients with cardiovascular disease; it is therefore essential to have normal reference values in healthy children. Objective: The aim of this study was to perform cardiopulmonary exercise testing in healthy children to obtain reference values in our laboratories. Methods: Cardiopulmonary exercise testing was performed in 215 healthy children divided into 2 groups: A, Prepubertal and B, Pubertal. These groups were in turn divided into male and female. The test was performed on a treadmill with O2 saturation and breath-by-breath expired gas analysis with a COSMED system. Statistical analysis was performed with SPSS 17 software package. Results: The A and B groups are significantly different in age, weight, height, and body surface area. Significant differences were found between the two groups in VO2 ml/min (p <0.0000), respiratory exchange ratio (p <0.01), O2 pulse in ml/bpm (p < 0.0000) and VE/VCO2 slope (p <0.0000). In the analysis by gender there were significant differences in peak VO2 ml/kg/ min, peak VO2 ml/min, MET, VE/VCO2 slope and VO2 ml/kg/min in ventilatory anaerobic threshold. Group A also showed significant gender difference in peak heart rate. VO2 ml/min and peak O2 pulse (VO2 ml/heart rate) increased with age and body surface area. The VE/VCO2 slope decreases with age. Conclusions: The data obtained in this study allow analysis of cardiopulmonary exercise testing variables in healthy children according to age and gender. These values can be used as reference data to evaluate patients with cardiovascular disease in Argentina.

Spirometric reference values for healthy Han children aged 5-15 years in Guangzhou, southern China.

Reliable interpretation of spirometry rests on appropriate reference values, but there are few published reference values for healthy children in China. To develop the updated spirometric normative values for healthy children aged 5-15 years in Guangzhou, southern China, and to explore the differences by comparison with published reference values. In this cross-sectional study, health questionnaire and physical examination conducted for screening healthy Han children. Spirometry was performed by well-trained technicians according to American Thoracic Society guidelines. Using Lambda-Mu-Sigma (LMS) algorithm, predicted equations for the median and lower limits of normal were derived for forced vital capacity (FVC), forced expiratory volume in one second (FEV1 ), peak expiratory flow (PEF), and maximal mid-expiratory flow (FEF25-75% ). Predicted values were compared with other published spirometric reference equations. Data were obtained from 422 healthy children (226 boys and 196 girls) aged 5-15 years. Spirometric parameters showed moderate-to-strong positive correlations with age, height, and weight in both genders, with height being the most crucial predictor. There were significant differences between spirometric values and other published reference values. Spirometric values were comparable with the data derived from the same area population in 2002, with exception of increased height and weight in the equivalent age groups. The present spirometric reference equations are feasible for assessment of lung function among children in southern China. Further studies for establishment of reference values for Chinese children in other regions are needed.

Comparison of six-minute walk test in children with moderate/severe asthma with reference values for healthy children

Objectiveto compare physical performance and cardiorespiratory responses in the six-minute walk test (6MWT) in asthmatic children with reference values for healthy children in the same age group, and to correlate them with intervening variables. Methodsthis was a cross-sectional, prospective study that evaluated children with moderate/severe asthma, aged between 6 and 16 years, in outpatient follow-up. Demographic and spirometric test data were collected. All patients answered the pediatric asthma quality of life (QoL) questionnaire (PAQLQ) and level of basal physical activity. The 6MWT was performed, following the American Thoracic Society recommendations. Comparison of means was performed using Student's t-test and Pearson's correlation to analyze the 6MWT with study variables. The significance level was set at 5%. Results40 children with moderate or severe asthma were included, 52.5% males, 70% with normal weight and sedentary. Mean age was 11.3 ± 2.1 years, mean height was 1.5± 0.1 m, and mean weight was 40.8 ± 12.6 Kg. The mean distance walked in the 6MWT was significantly lower, corresponding to 71.9% ± 19.7% of predicted values; sedentary children had the worst values. The difference between the distance walked on the test and the predicted values showed positive correlation with age (r = 0.373, p = 0.018) and negative correlation with cardiac rate at the end of the test (r = –0.518, p < 0.001). Regarding QoL assessment, the values in the question about physical activity limitations showed the worst scores, with a negative correlation with walked distance difference (r= –0.311, p = 0.051). Conclusionsasthmatic children's performance in the 6MWT evaluated through distance walked is significantly lower than the predicted values for healthy children of the same age, and is directly influenced by sedentary life style.

Comparison of self‐reported physical activity in children and adolescents before and during cancer treatment

Physical activities are important for the development of children and increasing evidence suggests beneficial effects of physical activity promotion during cancer treatment as well. The present study aimed at evaluating the current need of exercise interventions in pediatric cancer patients undergoing acute treatment and identifying risk factors for inactivity. Data about self-reported physical activity before and during treatment was collected in a cross-sectional design with the physical activity questionnaire from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) in a modified cancer specific version. One hundred thirty pediatric cancer patients with various entities were questioned 3.0 ± 1.6 months since diagnosis. Patients' activity levels before diagnosis mainly matched reference values for healthy children in Germany. Reductions during treatment affected all dimensions of daily physical activities and minutes of exercise per week decreased significantly (P < 0.001). Largest reductions of physical activities during treatment were identified for bone tumor patients and in-patient stays. Due to the well known importance of physical activity during childhood and the identified risk of inactivity during cancer treatment, supervised exercise interventions should be implemented into acute treatment phase to enhance activity levels and ensure a continuously support by qualified exercise professionals.

Comparison of six-minute walk test in children with moderate/severe asthma with reference values for healthy children

Objectiveto compare physical performance and cardiorespiratory responses in the six-minute walk test (6MWT) in asthmatic children with reference values for healthy children in the same age group, and to correlate them with intervening variables. Methodsthis was a cross-sectional, prospective study that evaluated children with moderate/severe asthma, aged between 6 and 16 years, in outpatient follow-up. Demographic and spirometric test data were collected. All patients answered the pediatric asthma quality of life (QoL) questionnaire (PAQLQ) and level of basal physical activity. The 6MWT was performed, following the American Thoracic Society recommendations. Comparison of means was performed using Student's t-test and Pearson's correlation to analyze the 6MWT with study variables. The significance level was set at 5%. Results40 children with moderate or severe asthma were included, 52.5% males, 70% with normal weight and sedentary. Mean age was 11.3±2.1 years, mean height was 1.5±0.1 m, and mean weight was 40.8±12.6 Kg. The mean distance walked in the 6MWT was significantly lower, corresponding to 71.9%±19.7% of predicted values; sedentary children had the worst values. The difference between the distance walked on the test and the predicted values showed positive correlation with age (r=0.373, p=0.018) and negative correlation with cardiac rate at the end of the test (r=-0.518, p<0.001). Regarding QoL assessment, the values in the question about physical activity limitations showed the worst scores, with a negative correlation with walked distance difference (r=-0.311, p=0.051). Conclusionsasthmatic children's performance in the 6MWT evaluated through distance walked is significantly lower than the predicted values for healthy children of the same age, and is directly influenced by sedentary life style.

Predictive equations using regression analysis of pulmonary function for healthy children in Northeast China.

BackgroundThere have been few published studies on spirometric reference values for healthy children in China. We hypothesize that there would have been changes in lung function that would not have been precisely predicted by the existing spirometric reference equations. The objective of the study was to develop more accurate predictive equations for spirometric reference values for children aged 9 to 15 years in Northeast China.Methodology/Principal FindingsSpirometric measurements were obtained from 3,922 children, including 1,974 boys and 1,948 girls, who were randomly selected from five cities of Liaoning province, Northeast China, using the ATS (American Thoracic Society) and ERS (European Respiratory Society) standards. The data was then randomly split into a training subset containing 2078 cases and a validation subset containing 1844 cases. Predictive equations used multiple linear regression techniques with three predictor variables: height, age and weight. Model goodness of fit was examined using the coefficient of determination or the R2 and adjusted R2. The predicted values were compared with those obtained from the existing spirometric reference equations. The results showed the prediction equations using linear regression analysis performed well for most spirometric parameters. Paired t-tests were used to compare the predicted values obtained from the developed and existing spirometric reference equations based on the validation subset. The t-test for males was not statistically significant (p>0.01). The predictive accuracy of the developed equations was higher than the existing equations and the predictive ability of the model was also validated.Conclusion/SignificanceWe developed prediction equations using linear regression analysis of spirometric parameters for children aged 9–15 years in Northeast China. These equations represent the first attempt at predicting lung function for Chinese children following the ATS/ERS Task Force 2005 guidelines on spirometry standardization.

MOON-test - Determination of Motor Performance in the Pediatric Oncology

Pediatric cancer patients suffer from various negative consequences due to the disease, the medical therapy and the inactivity during the intensive treatment. Only few studies have systematically identified the adverse effects of cancer on motor performance in childhood. To determine the motor performance of pediatric cancer patients, a motor performance test was developed which is applicable for this specific patient group. Eight test items with reference values for healthy children were merged to the MOON-test (test for motor performance in the oncology). MOON was tested for feasibility and acceptance in 33 patients aged 4-18 years. Feasibility was confirmed for children with different types of cancer (hematological malignancies and solid tumors) and with amputation, endoprosthesis, during aplasia as well as reduced general condition. Furthermore the patients showed a broad acceptance. Based on the study findings, the use of MOON-test as a standardized motor performance diagnostic tool in clinical routine of oncological acute clinics as well as rehabilitation clinics can be recommended.·

Salivary cortisol monitoring: Determination of reference values in healthy children and application in asthmatic children

Venipuncture testing of adrenocortical function in asthmatic infants and young children receiving inhaled corticosteroids can raise cortisol levels and mask physiological responses. This study aimed to establish reference ranges for salivary cortisol levels and evaluate the safety and effects of jet-nebulized budesonide inhalation suspension (BIS) on salivary cortisol levels and patient outcomes in infants and young children with mild or persistent asthma. Reference salivary cortisol levels were determined in healthy children aged 6 months to 4 years old. A 12-week multicenter, randomized, parallel-group, open-label study was performed involving 53 age-matched asthmatic children who received either 0.5 mg/day of BIS or 40-60 mg/day of cromolyn sodium inhalation suspension (CIS) via compressor nebulizer. The effective measuring range of salivary cortisol concentration in asthmatic children was 0.12-3.00 micrograms/dL. The upper and lower limits of the reference range were 0.827 and 0.076 micrograms/dL, respectively. No significant difference was seen from baseline through week 12 in the CIS and BIS groups. BIS was safe in these patients, with no inhibitory effects on adrenocortical function. Salivary cortisol measurement offers a useful and accurate tool for testing adrenocortical function in infants and young children. Longer-term studies that incorporate testing of the hypothalamic-pituitary-adrenal axis are warranted to confirm our findings.

532 Maximum Expiratory Flow in Health Children from the Metropolitan Area of Monterrey Mexico

BackgroundStudies have been conducted to obtain MEF (maximum expiratory flow) reference values in healthy children. Factors such as the region´s altitude, humidity, local temperature, and the characteristics of the study population cause changes in airway resistance that produce different MEF values. The objetive of this study is to establish normal reference values for MEF in healthy children from the metropolitan area of Monterrey, Nuevo Leon, Mexico and compare them with established reference values from other states of Mexico and the United States.MethodsWe carried out an observational, cross-sectional, descriptive, comparative study in healthy 6 to 8 year old children, both gender. A questionnaire that included information about age, weight, and height was applied. Flowmetry was performed with a Truzone portable peak flow meter and the highest of 3 values was recorded.ResultsWe included 2282 children (1085 boys and 1197 girls) from 19 randomly selected elementary schools. The MEF values obtained were plotted on graphs in MEF percentiles according to gender and height. When compared with MEF reference values for authors from different locations, differences were found.ConclusionsThe variation observed in MEF values in our population compared with studies performed in other populations shows the need for clinical demographic data from each region to establish and use characteristic reference values.

Age-dependent T and B lymphocyte subsets defined by multicolor flow cytometry (86.13)

Abstract Immune dysregulation in children due to primary immunodeficiency, autoimmune disease or immunomosuppressive therapy may be characterized in detail by multiparametric flow cytometry. To determine age-dependent reference values for healthy children, we developed four panels: aß and γδ T lymphocytes; regulatory T lymphocytes; B lymphocytes; NK and NK T cells. Detailed analyses performed on 18 healthy subjects aged 8 to 46 years revealed differences between adult and juvenile phenotypes in 66 of 301 distinct subsets. Among naïve aß T lymphocytes (CD45RA+CCR7+CD27+) we found a 60% decrease in the CD4+ subset but no change in the CD8+ subset in adults compared to children. Expression of CD31, an aß T lymphocyte marker of recent thymic emigration, decreased 50% with age. T regulatory cells (CD4+CD127loCD25+FoxP3+) were 30% lower in adults. No differences were found in major γδ T lymphocyte, NK, or NK T cell subsets. Memory B cells (CD38loCD24+) increased 2-fold with age, while naïve B cells (CD24hiCD38+IgM+IgD-) decreased by 50%. Thus, the influence of aging greatly effects subset frequencies, and may reflect decreasing thymus function and acute/chronic stimulation of memory B and T lymphocytes. Phenotypic analysis of leukocyte subsets may serve as a valuable tool for detecting and monitoring immune dysregulation in children, but age-matched controls are essential. Supported by the McMillen Foundation