ALERGIA A LA PROTEíNA DE LA LECHE DE VACA. EVALUACIóN DE SU RESOLUCIóN ESPONTáNEA POR MEDIO DE DESAFíOS DOBLE CIEGO PLACEBO CONTROLADOS / cows milk allergy. an assesment of its spontaneous resolution through double blind placebo controlled challenges.

Introducción. la alergia a la leche de vaca (aplv) es un problema sanitario global. Su diagnóstico adecuado y su seguimiento son esenciales ya que la leche de vaca es un alimento importante en la dieta de muchos lactantes. los desafíos orales doble ciego controlados por placebo (ddcpc) son la herramienta ideal para el diagnóstico y seguimiento de las alergias alimentarias. este estudio describe las características evolutivas de pacientes con aplv y las posibles variables que la pudieran modificar. material y métodos. Se estudiaron pacientes con diagnóstico de aplv previo con desafíos abiertos. Se catalogaron las reacciones de acuerdo a la normativa dracma. positivas fueron las pruebas en las que se presentaron alteraciones clínicas o variaciones hemodinámicas. negativas fueron aquellas en las que el paciente toleró la leche. Se consideraron edades de inicio y de realización del ddcpc, sexo y patología de aplv. resultados. Se estudiaron 106 pacientes (50 masculinos, 56 femeninos), promedio edad de inicio de síntomas 5,31 m (rango: 1-48 meses) y al procedimiento 23,14 m (5 meses - 5 años), y 13 pruebas positivas. un conjunto se refirió al mecanismo fisiopatológico y se dividió en ige mediadas (n=55) con 8 pruebas positivas y mixtas/celulares (n=51) con 5 pruebas positivas. otro conjunto fueron no gastrointestinales (n=61) con 7 pruebas positivas y gastrointestinales (n=45) con 6 pruebas positivas. todos los grupos fueron similares en cuanto a las variables demográficas. el sexo masculino y el diagnóstico de anafilaxia fueron factores de riesgo para no resolver su aplv (p=0,0125 y p=0,002 respectivamente). conclusiones. el momento de resolución de la aplv es independiente del mecanismo fisiopatológico subyacente o la edad de inicio de los síntomas. en general resuelven el problema de manera espontánea hacia los dos años de vida en más de un 87% de los casos. el sexo masculino (en ige mediadas) y el antecedente de anafilaxia podrían ser factores de riesgo para tener menos probabilidades de resolver la APLV. (AU)

Introduction: cow´s milk allergy (cma) is a global health issue. a proper diagnosis and follow up become essential. double blind placebo controlled challenges (dbpcc) is the gold standard for this purpose. this paper describes clinical evolution and characteristics of cma, as well as variables that may modify the affection course. methods & material: a group of patients, with a previous diagnosis of cma by open challenges, has been studied and its results cataloged according to dracma guidelines. tests with hemodynamic changes or clinical symptoms were considered as positives, while those with no clinical reaction were considered as negatives. variables involved were: age of symptoms starting, age of dbpcc performing, gender and cma clinical manifestations. results: 106 patients has been studied (50 male, 56 female), with a median age of 5,31 mo (range 5 ­ 48 mo) at the starting symptoms, and a median age of 23,14 mo (range 5 mo ­ 5 y) at the performing of dbpcc. 13 tests were negative. as regards to the different immune mechanisms, 55 were ige dependent (8 negative), and 51 were mediated by mixed/cellular (5 negative). patients were divided into two groups: with gastrointestinal symptoms (n=45) and with no gastrointestinal symptoms (n=61). they showed 6 and 7 negative results, respectively. all groups were similar. male gender, and anaphylaxis diagnosis turned out to be risk factors not to resolve cma (p=0,0125 and p=0,002 respectively). conclusions: cma resolution is independent of the immune mechanisms involved or the age of its symptoms starting. cma is solved spontaneously towards the age of two in 87% of the cases. male gender, and anaphylaxis may become risk factors not to resolve cma.(AU)

Alergia al huevo en Pediatría. Documento del Comité de Pediatría de la Asociación Argentina de Alergia e Inmunología Clínica / Egg allergy in pediatrics. Pediatric Committee document of the Argentina Association of Allergy and Clinical Immunology

El huevo de gallina es una fuente de proteínas de alto valor biológico de bajo costo y de vitaminas del complejo B, importantes para la alimentación del niño. Culturalmente es uno de los alimentos básicos de nuestra dieta y, debido a esto, la alergia a sus proteínas es una de las más frecuentes en la infancia y tiene su mayor impacto en niños en edad preescolar. Estos niños representan una población vulnerable debido a que se encuentran en una etapa importante de su crecimiento y desarrollo, y el tratamiento de esta patología genera la adopción de dietas restrictivas que pueden impactar en forma negativa en su salud y calidad de vida. Este impacto está dado en parte por la ubicuidad de sus proteínas, que limita ampliamente la dieta y genera riesgos de reacciones alérgicas que se incrementan a medida que el niño crece y alcanza una mayor independencia. Teniendo en cuenta la importancia de esta patología, el Comité de Pediatría realizó una revisión actualizada con el fin de proveer herramientas útiles para el manejo adecuado de la misma. (AU)

Eggs are a source of low cost high biological value protein and complex B vitamins important for the child's nutrition. Culturally it is one of the staples of our diet and because of this, egg allergy is one of the most common food allergies in childhood and has its greatest impact on preschool children. These children represent a vulnerable population because they are at an important stage in their growth and development and the treatment of this condition generates the adoption of restrictive diets that may impact negatively on their health and quality of life. This impact is given in part by the ubiquity of their proteins that largely restrict the diet and generates risks of allergic reactions that increase as the child grows and earns greater independence. Given the importance of this issue the Pediatrics Committee conducted an updated review to provide useful tools to manage this condition.(AU)

Estudio multicéntrico de evaluación del conocimiento de los pediatras acerca de reacciones alérgicas a vacunas para enfermedades infecciosas / A multicenter study assessing pediatrician's knowledge about allergic reactions to infectious disease vaccines

Resumen. Las reacciones alérgicas a las vacunas contra agentes infecciosos han generado preocupación entre los pediatras. Sin embargo, se desconoce el grado de información que tienen estos especialistas de nuestro país sobre este tema. Objetivo. Contar con datos estadísticos acerca de este problema. Población. Trescientos veinte pediatras encuestados. Método. Estudio multicéntrico descriptivo prospectivo de corte transversal realizado con encuestas estandarizadas Resultados. El 12,5% de los encuestados reconoció la presencia de síntomas de aparición rápida como reacción de hipersensibilidad inmediata. (61,6%) consideró a estas reacciones como infrecuentes. El 72,6% reconoció a la neomicina como causa de alergia, el 51,6 % al timerosal, el 73% a los conservantes, un 30,4% a la gelatina y la mitad de los encuestados al componente activo. El 62,3% reconoció a la proteína del huevo como componente de la vacuna MMR. Ante antecedentes de alergia al huevo, el 35% de los médicos contestó que contraindica siempre las vacunas que contienen proteína del huevo, el 14% no las contraindica nunca y el 9% no sabe. Los médicos de menos de 5 años de recibidos reconocieron con mayor frecuencia la presencia de una reacción alérgica a vacunas (p = 0,004). Los médicos de más de 10 años de recibidos solicitan más frecuentemente interconsulta con el especialista ante casos de vacunación de pacientes con alergia a la proteína del huevo (p = 0,01). Conclusiones. Existe un grado importante de desconocimiento acerca de las reacciones alérgicas a vacunas, los componentes de las vacunas involucrados en dichas reacciones y las conductas a tomar frente a pacientes con alergia al huevo.(AU)

Background: Allergic reactions to infectious disease vaccines have generated concern among pediatricians. It is unknown the level of pediatrician's knowledge about this issue. The aim of this study is to obtain statistical data about this issue in our country. Population: 320 pediatricians. Methods: A transversal prospective descriptive multicenter study by means of a survey. Results: 12.5% of participants were capable to identify symptoms of immediate hypersensitivity reactions and 61.6% considered that these reactions are not frequent. The pediatricians pointed out as the most commonly allergen components the following ones: Neomicine (72.6%), thymerosal (51.6 %), preservatives (73%), gelatin (30.4%) and active component (nearly 50%). 62.3% knew that eggs proteins are part of MMR vaccine. In the case of patient with history of egg allergy, 35% answered that they always contraindicate vaccination with egg protein vaccines while14% do not contraindicate and 9% do not know what to do. Physicians less than 5 years of graduation recognized more frequently the presence of allergic reactions (p: 0.004). Physicians with 10 or more years of graduation asked for specialist opinion more frequently in the case of patients with egg allergy (p: 0.01). Conclusions: It was found an important lack of information about allergic vaccine reactions, the involved vaccine constituents and the correct management of situations related to egg allergy.(AU)

Serum IGF-I and IGFBP-3 reference values from a chemiluminescent assay in normal children and adolescents of hispanic and italian origin: presence of sexual dimorphism in IGF-I values.

Serum IGF-I and IGFBP-3 assays are used to monitor rhGH treatment. Some discrepancies in results obtained by means of different assays have been reported. The aim of this study was to establish normal ranges for circulating IGF-I and IGFBP-3 in children and adolescents of Hispanic and Italian origin. Circulating levels of IGF-I and IGFBP-3 were measured in 169 Hispanic and Italian prepubertal children and 66 adolescents of both sexes, using a chemiluminescent assay. Serum levels of IGF-I and IGFBP-3 increased from early childhood into adolescence. After pubertal peaks of IGF-I and IGFBP-3, slight decreases were observed with increasing age. Furthermore, serum IGF-I levels were significantly higher in girls than in boys, suggesting a sexual dimorphism in serum IGF-I values in late prepuberty and early puberty. Differences in IGF-I and IGFBP-3 absolute values between our study and previous studies suggest the need to establish reference ranges for each ethnic group.

Differences in serum GH cut-off values for pharmacological tests of GH secretion depend on the serum GH method. Clinical validation from the growth velocity score during the first year of treatment.

BACKGROUND: The serum GH cut-off value for pharmacological tests of GH secretion (PhT GH) depends on the type of test and also on the method used for determining serum GH. Cut-off serum GH values as different as 5-10 ng/ml, have been reported, and have been validated biochemically. We have used the growth velocity (GV)-standard deviation score (SDS) during the first year of treatment with rhGH to validate these cut-offs on a biological basis. METHODS: Fifty pre-pubertal patients with short stature (height < or =-2 SDS and GV < or =-1.2 SDS) were studied. GH deficiency (GHD) was diagnosed in 39 patients, on the basis of clinical and auxological parameters and on the serum concentration of IGF-1, and non-GHD in the other 11 patients. Two PhT GH (arginine and clonidine) were carried out in the 50 patients. Serum GH was determined by two different methods: one detecting most of serum GH isoforms, named Total GH (HGH Bio-Tech, MAIA Clone), and another one, only detecting the 22 kDa GH, named 22K GH (GH-22K IFMA, Wallac). RESULTS: Basal data: all patients with GHD and with non-GHD had maximal serum GH response (MaxR) values below and above the cut-off, respectively, for the serum Total GH and 22K GH. The mean 22K GH/Total GH ratio was similar to previous publications. Post-rhGH treatment data: the two groups improved their height SDS during the first year of treatment, particularly patients with GHD. A receiver-operator curve was used to define the best threshold for post-treatment GV-SDS that separates GHD from non-GHD patients. This value was 1.91 GV-SDS. A negative correlation between first year treatment GV-SDS and pre-treatment serum GH MaxR was found for the two assays (p < 0.001). Then, the best cut-off GV-SDS, previously calculated with the receiver-operator curve (1.91 SDS) was used to interpolate the corresponding serum GH values, as determined by the two methods. For Total GH, the value was 10.8 ng/ml, and for 22K GH, it was 5.4 ng/ml. CONCLUSION: The cut-off values calculated by biological means to separate GHD from non-GHD were remarkably similar to those calculated biochemically (10.0 and 4.8 ng/ml, respectively) for Total and 22K GH. This is a biological validation for using different cut-off values, appropriate for each assay, to diagnose GHD.

Dose dependency of the serum bio/immuno GH ratio in children during pharmacological secretion tests.

Dissociation between GH bioactivity (bio-GH) and GH immunoactivity (immuno-GH) is due to the heterogeneity of the molecule: the measurements do not always provide reliable information on the bio-GH. We studied the ratio of bio-GH and immuno-GH during pharmacological secretion tests in 211 sera to study the concentration-response curve of the assay (C1), 16 samples of normally growing subjects with idiopathic short stature (C2), 13 samples from patients with GH deficiency (GHD1) and 6 samples of 3 patients with GHD and normal provocative tests (GHD2). GH bioactivity was determined by the Nb2 cell proliferation assay (bio-GH) and immuno-GH by a time-resolved immunofluorometric assay (IFMA) (immuno-GH). A non-linear negative relationship between the serum bio-GH/immuno-GH ratio and serum immuno-GH was observed in C1. In log-log plotting representation, two cut-off lines were drawn: a vertical cut-off line separating above-below cut-off serum peak immuno-GH values in provocative tests, and a diagonal cut-off line separating normal-abnormal serum bio-GH/immunoGH ratio; four areas were defined. GHD1 had normal ratios, but below cut-off peak immuno-GH responses. P2 and P3 of Group GHD2 had abnormal ratios in samples with low serum immuno-GH but only P2 had autosomal dominant mutation. P1 had the same autosomal dominant isolated GHD as P2 but a low normal ratio. Our data underline the importance of relatively low serum GH concentrations in mediating GH biological actions. An abnormal serum bio-GH/immuno-GH ratio might explain certain cases of GHD and might be useful in detecting abnormal circulating isoforms of GH in patients with growth failure.