Immunoproteomics of cow's milk allergy in Mexican pediatric patients.

Immunological mechanisms of non-IgE-mediated cow's milk protein allergy (CMPA) are not well understood. Such a circumstance requires attention with the aim of discovering new biomarkers that could lead to better diagnostic assays for early treatment. Here, we sought both to investigate the mechanism that underlies non-IgE-mediated CMPA and to identify cow's milk immunoreactive proteins in a Mexican pediatric patient group (n = 34). Hence, we determined the IgE and IgG1-4 subclass antibody levels against cow's milk proteins (CMP) by ELISA. Then, we performed 2D-Immunoblots using as first antibody immunoglobulins in the patients'serum that bound specifically against CMP together with CMP enrichment by ion-exchange chromatography. Immunoreactive proteins were identified by mass spectrometry-based proteomics. The serological test confirmed absence of specific IgE in the CMPA patients but showed significant increase in antigen-specific IgG1. Additionally, we identified 11 proteins that specifically bound to IgG1. We conclude that the detection of specific IgG1 together with an immunoproteomics approach is highly relevant to the understanding of CMPA's physiopathology and as a possible aid in making a prognosis since current evidence indicates IgG1 occurrence as an early signal of potential risk toward development of IgE-mediated food allergy. SIGNIFICANCE: Allergies are one of the most studied topics in the field of public health and novel protein allergens are found each year. Discovery of new principal and regional allergens has remarkable repercussions in precise molecular diagnostics, prognostics, and more specific immunotherapies. In this context, specific IgE is widely known to mediate physiopathology; however, allergies whose mechanism does not involve this immunoglobulin are poorly understood although their incidence has increased. Therefore, accurate diagnosis and adequate treatment are delayed with significant consequences on the health of pediatric patients. The study of type and subtypes of immunoglobulins associated with the immunoreactivity of cow's milk proteins together with an immunoproteomics approach allows better comprehension of physiopathology, brings the opportunity to discover new potential cow's milk protein allergens and may help in prognosis prediction (IgG1 occurrence as an early signal of possible risk toward development of IgE-mediated food allergy).

Magnetic fields and acute leukemia in children with Down syndrome.

BACKGROUND: : We analyzed effects of exposure to magnetic fields on the expression of acute leukemia in children with Down syndrome (who have a 20-fold higher risk of leukemia). METHODS: : We performed a case-control study that included 42 children with both acute leukemia and Down syndrome as cases and 124 healthy children with Down syndrome as controls. We obtained demographic information concerning the children and took spot measurements of magnetic fields at each residence. RESULTS: : The odds ratio for direct measurements of magnetic fields >/=6.00 mG was 3.7 (95% confidence interval = 1.05-13.1). CONCLUSION: : The association between magnetic fields and leukemia in children with Down syndrome suggests the possibility of a causal role for magnetic fields in the etiology of leukemia among a genetically susceptible subgroup of children.

Biology, clinical, and hematologic features of acute megakaryoblastic leukemia in children.

To assess the incidence, clinical features at presentation, hematologic, immunophenotypic, and cytogenetic characteristics of AMKL in children we prospectively studied 834 consecutive non selected children with newly diagnosed acute leukemia (AL) admitted to the Hematology Department at the Instituto Nacional de Pediatría (INP), Mexico, D.F. We found 682 cases (81.8%) with a typical ALL immunophenotype, and the remaining 152 (18.2%) were considered to have AML. In 29 of the 152 patients with AML studied, a diagnosis of AMKL was established. These 29 cases represented 19.1% of the cases of AML and 3.48% of the total cases of AL during the time span covered by the study. Twenty-four percent of the cases occurred in infants 2 years old or younger and 41.4% occurred in children 41 months of age or younger. In contrast, in only 18.6% of the patients with AML (M0-M6), the diagnosis was established before 42 months of age and in 17% before their second year of life. Clinical presentation was not strikingly different than that observed in patients with other types of AML, and the time interval from onset of symptoms to diagnosis was also similar, though in a small subset of patients, the clinical course was characterized by a chronic slowly progressive disorder extending over weeks or months resembling smoldering leukemia or chronic myelofibrosis with agnogenic myeloid metaplasia. Bone marrow (BM) fibrosis was a constant features in our patients; 75% of the patients studied showed this complication at the time of diagnosis. Some rather unusual findings in this study were intense skeletal pains from multiple osteolytic lesions, the presence of soft-tissue tumor, and the presence of cohesive scanty clusters of primitive-looking blast cells in BM aspirates. Several interesting cytogenetic findings in our study were t(1;22)(p13;q13) in a 14-year-old boy, t(9;22)(q34;q11) in one patient, and monosomy 7 in two patients. Another important finding in our study was the clinical association with colonic adenocarcinoma in one patient, an association that to our knowledge has not been reported previously. In conclusion, our data suggest that the incidence of AMKL in Mexico might be higher than those reported in Caucasian white pediatric population, and that biologic and cytogenetic profile may differ from those of western countries, but more studies are needed to corroborate cytogenetic heterogeneity, ethnic and geographic diversity. Early onset of the disease, low WBC counts, slight thrombocytopenia or normal platelet counts, and BM fibrosis were characteristic distinctive features of at least half of the patients with this subtype of AML.

Eritropoyetina en el tratamiento de la anemia en niños en hemodiálisis / Erythropoietin in the treatment of anemic children in hemodialysis

La anemia de la insuficiencia renal tiene origen multifactorial; el más importane es la disminución de la producción de eritropoyetina por las células renales peritubulares. La administración de esta hormona permite corregir la anemia. Se trató la anemia de siete niños en hemodiálisis con eritropoyetina recombinante humana. La dosis inicial fue de 150-250 U/kg/semana y la dosis de mantenimiento 100-200 U/kg/semana. La hemoglobina se elevó de 5.8 g/dL a 10 g/dL en promedio; tres pacientes presentaron ferropenia y falta de respuesta transitoria a la hormona a pesar del uso profiláctico de hierro. Mejoró la calidad de vida al corregirse la anemia y los pacientes no requirieron transfusiones después de 20 semanas. Tres pacientes desarrollaron trombosis en el sitio del acceso vascular; no hubo otros efectos colaterales. La eritropoyetina es útil en el tratamiento de la anemia de la insuficiencia renal con pocos efectos colaterales en niños

Púrpura fulminante idiopática / Purpura fulminans idiopatic

Introducción. La púrpura fulminante (PF) es una enfermedad rara que se caracteriza por la aparición súbita de hemorragia cutánea, formación de bulas y flictenas, necrosis de la piel y tejido subcutáneo. La evolución espectacular, rápidamente progresiva y la propagación por oleadas orientan acerca de la índole grave de la enfermedad. Material y métodos. Se analizan las características clínicas y hematológicas, y la evolución de 10 pacientes con diagnóstico de PF admitidos al Servicio de Hematología del Instituto Nacional de Pediatría en el período 1979-1993. Resultados. Se observó una distribución similar de acuerdo al sexo. La edad de presentación más frecuente fue la preescolar (60 por ciento), con una frecuencia similar en la lactancia y en la edad escolar. La mayor frecuencia de la enfermedad se observó en primavera y verano. Sólo 3 pacientes presentaron alteraciones hemostáticas compatibles con coagulopatía por consumo en el momento del diagnóstico. Todos los pacientes recibieron heparina, esteroides y antibióticos y algunas otras medidas adicionales por un período promedio de 7 días, con variaciones de 5 a 14 días. La evolución fue excelente en el 60 por ciento de los pacientes que no presentaron ningún tipo de secuelas. Se practicó amputación en 4 de los pacientes. En uno de los pacientes amputados se observó colonización e infección sistémica subcecuente a Aeromonas shigelloides y Pseudomonas sp, sucumbiendo a la infección. Un diagnóstico erróneo en otras instituciones y la institución de un tratamiento anticoagulante tardío fue el responsable de las secuelas irreversibles observadas en 2 pacientes. Conclusiones. La PF es una enfermedad de la niñez de curso clínico agresivo, que hacen de ella una verdadera urgencia hematológica. La incapacidad para sospechar el diagnóstico tiene una influencia pronóstica desfavorable y contribuye a una morbimortalidad elevada