Thymopoiesis and regulatory T cells in healthy children and adolescents

OBJECTIVES: The purpose of this study was to investigate the association between T cell receptor excision circle levels in peripheral blood mononuclear cells and regulatory T cells that co-express CD25 and Foxp3 in healthy children and adolescents of different ages. MATERIALS AND METHODS: The quantification of signal-joint T-cell receptor excision circle levels in the genomic DNA of peripheral blood mononuclear cells was performed using real-time quantitative PCR. The analysis of CD4, CD8, CD25, and Foxp3 expression was performed using flow cytometry. RESULTS: Ninety-five healthy controls (46 females and 49 males) ranging in age from 1 to 18 years were analyzed. The mean T-cell receptor excision circle count in all individuals was 89.095¡36.790 T-cell receptor excision circles per microgram of DNA. There was an inverse correlation between T-cell receptor excision circles counts and age (r = -0.846; p<0.001) as well as between the proportion of CD4+CD25+Foxp3+ T cells and age (r = -0.467; p = 0.04). In addition, we observed a positive correlation between the amount of CD4+CD25+Foxp3+ T cells and the amount of Tcell receptor excision circles per microgram of DNA in individuals of all ages (r = -0.529; p = 0.02). CONCLUSIONS: In this study, we observed a decrease in the thymic function with age based on the fact that the level of T-cell receptor excision circles in the peripheral blood positively correlated with the proportion of regulatory T cells in healthy children and adolescents. These findings indicate that although T-cell receptor excision circles and regulatory T cells levels decrease with age, homeostasis of the immune system and relative regulatory T cells population levels are maintained in the peripheral blood

Metabolic and hematologic changes occurring after rapid intravenous infusion of gammaglobulin in patients with antibody deficiency syndromes

OBJECTIVE: We wished to investigate whether increased IgG infusion rates are associated with metabolic and hematologic changes in pediatric patients with antibody deficiency syndromes.METHODS: We studied 7 patients (2-16 years old) with primary antibody deficiencies who had been on regular IgG replacement treatment, 350-600 mg/kg/dose every 3 weeks with a 3% IVIG preparation, for periods ranging from 6 months to 4 years. Initially, the IgG concentration of IVIG preparations was increased to 6, 9 and 12% in consecutive infusions at a constant IgG infusion rate of 4 mg/kg/min. Subsequently, the infusion rates were increased to 8, 12, and 16 mg/kg/min using the IVIG 12% preparation.RESULTS: Clinically, all patients tolerated increases in IVIG concentrations while the infusion rate was 4 mg/kg/min. However, 3 patients presented side effects when the infusion rate was increased to 8 and 16 mg/kg/min.CONCLUSION: We conclude that metabolic and hematologic sides effects occur with rapid infusion of IVIG even in patients who tolerate the increased infusion rate clinically. The advantages of using high infusion rates have to be re-evaluated.OBJETIVO: Nós pretendemos investigar se o aumento de velocidade de infusão de gamaglobulina intravenosa (IVIG), está associada com alterações metabólicas e hematológicas em pacientes com deficiência de anticorpo. CASUÍSTICA E MÉTODO: Nós estudamos sete pacientes (2-16 anos) com deficiência primária de anticorpo que já estavam em tratamento com reposição regular de IgG, na dose de 350-600 mg/kg a cada três semanas em preparados a 3%, por períodos de seis meses a quatro anos. Inicialmente a concentração dos preparados de IVIG foi aumentando para 6, 9 e 12% em infusões consecutivas numa velocidade constante 4 mg/kg/min. Subseqüentemente, na segunda fase do estudo, mantivemos a concentração a 12% e a velocidade de infusão foi aumentando para 8, 12, e 16 mg/kg/min. RESULTADOS: Clinicamente, todos os pacientes toleraram o aumento da concentração de IVIG na velocidade constante de 4 mg/kg/min. Entretanto, 3 pacientes apresentaram efeitos colaterais quando a velocidade de infusão aumentou para 8 e 16 mg/kg/min. CONCLUSÃO: Nós concluímos que alterações metabólicas e hematológicas podem ocorrer quando se administra preparados de IVIG em altas concentração e velocidade mesmo que os pacientes tolerem bem clinicamente. As vantagens de utilizar velocidades elevadas na infusão de IVIG devem ser reavaliadas.Universidade Federal de São Paulo (UNIFESP)Escola Paulista de MedicinaInstituto de Ciências Biomédicas IIILouisiana State University Medical CenterUNIFESP, EPMSciEL

Recurrent pneumonias in patient with antibody deficiency and normal immunoglobulins

The authors report the case of a 7-year-old girl, with a history of recurrent respiratory infections since five months of age. Immunological evaluation at four years of age revealed a normal level of total serum immunoglobulins, but a deficient humoral response to Streptococcus pneumoniae. Although having all normal IgG subclasses, the patient had inadequate antibody levels to all serotypes tested (1, 3, 5, 6, 9, and 14). Concurrent radiological evaluation showed diffuse atelectasis and bronchiectasis. Patient was started on IVIG, and subsequent chest CT scan revealed resolution of the above-mentioned lesions. To prevent irreversible damage to lung parenchyma, due to recurrent lower respiratory infections, it is important to identify immunocompromised individuals and treat them accordingly.É relatado o caso de uma menina de sete anos de idade com infecções de vias aéreas de repetição (otites, pneumonias e sinusites) desde os cinco meses de vida. A avaliação imunológica demonstrou produção inadequada de anticorpos ao Streptococcus pneumoniae após imunização para todos os sorotipos (1, 3, 5, 6, 9 e 14) testados, embora a paciente apresentasse níveis normais de imunoglobulinas. A avaliação radiológica, no momento da admissão, demonstrou presença de atelectasias difusas associadas a bronquiectasias. Após início do tratamento com imunoglobulina endovenosa e fisioterapia respiratória houve esvaecimento gradual até reversão das alterações radiológicas. Demonstrou-se, assim, a importância de um diagnóstico preciso para início de tratamento específico, com melhora gradual do quadro clínico e radiológico, evitando seqüelas pulmonares irreversíveis.UNIFESP-EPM Departamento de PediatriaUNIFESP-EPM Departamento de Diagnóstico por ImagemUNIFESP-EPMUniversidade de São Paulo Instituto de Ciências Biomédicas Departamento de ImunologiaUNIFESP, EPM, Depto. de PediatriaUNIFESP, EPM Depto. de Diagnóstico por ImagemUNIFESP, EPMSciEL

Protective activity of the antilipopolysaccharide antibodies from human cord serum

We evaluated the ability of human maternal and cord serum antibodies to protect mice challenged with live Escherichia coli serotype O6:K2ac (E. coli O6). Mice received paired maternal or cord serum pools before a challenge with E. coli O6 to evaluate the mortality rate. All the pools were able to protect the animals challenged with bacteria except the test group from paired maternal and cord sera from preterm neonates containing less than 1.0 mg L-1 immunoglobulin G antibody levels. in liver, spleen and mesenteric lymph nodes from the control group (phosphate-buffered saline), more than 10(2) CFU mL(-1) bacteria were found at 30 min and more than 10(5) CFU mL(-1) after 120 min. the test group showed lower bacterial counts in the organs, and no bacteria in the mesenteric lymph nodes during the evaluated period. Tumor necrosis factor alpha and interleukin 6 were undetectable in serum from animals pretreated with paired maternal and cord serum pools from full-term neonates and pools from preterm neonates containing high antibody and avidity levels. Our findings suggest that placental transfer of antilipopolysaccharide O6 immunoglobulin G antibodies to neonates has a high capacity to prevent lethal infection with E. coli O6 in a mouse protection model and that the degree of protection is determined by the concentration and avidity of these IgG antibodies.Univ São Paulo, Inst Ciencias Biomed, Lab Imunol Mucosas, Dept Immunol, BR-05508900 São Paulo, BrazilUniv São Paulo, Dept Parasitol, Inst Biomed Sci, BR-05508900 São Paulo, BrazilUniv São Paulo, Sch Med, Dept Pediat, BR-05508900 São Paulo, BrazilUniv Fed Ceara, Dept Clin Anal & Toxicol, São Paulo, BrazilWeb of Scienc

Response to polysaccharide antigens in patients with ataxia-telangiectasia

OBJECTIVE: To analyze the production of antibodies to polysaccharide antigens in patients with ataxia-telangiectasia. PATIENTS AND METHODS: We used the ELISA technique to measure the levels of IgG antibodies to serotypes 1, 3, 5, 6B, 9V and 14 of Streptococcus pneumoniae in 14 patients with ataxia-telangiectasia before and after immunization with 23-valent polysaccharide vaccine. Adequate response to individual polysaccharide can be defined as a postimmunization antibody titer equal to or greater than 1.3 µg/ml or as a minimum fourfold increase over the baseline (preimmunization) value. RESULTS: Six (43%) patients showed an absent response to all serotypes analyzed. Four patients showed adequate response to only one serotype, one patient to two serotypes, two patients to three serotypes and only one patient to four out of six serotypes analyzed. No patient had adequate response to all serotypes tested. Postimmunization pneumococcus IgG levels were higher than preimmunization levels to all serotypes analyzed, except for serotype 3. In spite of this, the mean postimmunization levels were lower than 1.3 µg/ml in all serotypes, except for serotype 14. Mean increment was less than four in all serotypes analyzed. CONCLUSION: Our results suggest that patients with ataxia-telangiectasia are at a high risk of having an impaired response to pneumococcus, which may be one of the causes of recurrent sinopulmonary infections in these patients.OBJETIVO: Estudar a produção de anticorpos a antígenos polissacarídicos em pacientes com ataxia-telangiectasia CASUÍSTICA E MÉTODO: Utilizando a técnica de ELISA, determinamos os níveis de IgG aos sorotipos 1, 3, 5, 6B, 9V e 14 do pneumococo em 14 pacientes com ataxia-telangiectasia, antes e após a imunização com a vacina pneumocócica 23-valente. Resposta adequada a cada sorotipo foi definida como IgG > 1,3 µg/ml ou o incremento de quatro vezes dos níveis pós em relação aos pré-imunização. RESULTADOS: Seis pacientes (43%) não responderam a todos os sorotipos analisados, quatro a apenas um sorotipo, um paciente a dois, dois a três e apenas um paciente a quatro dos seis sorotipos analisados. Nenhum paciente apresentou resposta adequada a todos os sorotipos testados. Os níveis de IgG ao pneumococo pós-imunização foram superiores aos pré-imunização para todos os sorotipos testados, exceto o 3. Apesar disso, os valores médios pós-imunização foram inferiores a 1,3 µg/ml para todos os sorotipos analisados, exceto o 14. A média de incremento da resposta foi inferior a quatro para todos os sorotipos analisados. CONCLUSÃO: Nossos resultados sugerem que pacientes com ataxia-telangiectasia têm grande risco de apresentar resposta inadequada ao pneumococo, o que pode ser uma das causas das infecções sinopulmonares de repetição.Universidade Federal de São Paulo (UNIFESP)UNIFESP Departamento de PediatriaHospital Albert EinsteinUniversidade de São Paulo Faculdade de Medicina Departamento de PediatriaUniv. de São Paulo Instituto de Ciências Biomédicas Laboratório de Imunologia de MucosasUniversidade Federal do Ceará Faculdade de Farmácia Departamento de Análises Clínicas e ToxicológicasUNIFESP, Depto. de PediatriaSciEL

The use of reverse transcription-PCR for the diagnosis of X-linked chronic granulomatous disease

Chronic granulomatous disease (CGD) is an inherited disorder of the innate immune system characterized by a defective oxidative burst of phagocytes and subsequent impairment of their microbicidal activity. Mutations in one of the NADPH-oxidase components affect gene expression or function of this system, leading to the phenotype of CGD. Defects in gp91-phox lead to X-linked CGD, responsible for approximately 70% of CGD cases. Investigation of the highly heterogeneous genotype of CGD patients includes mutation analysis, Northern blot or Western blot assays according to the particular case. The aim of the present study was to use reverse transcription (RT)-PCR for the analysis of molecular defects responsible for X-linked CGD in eight Brazilian patients and to assess its potential for broader application to molecular screening in CGD. Total RNA was prepared from Epstein B virus-transformed B-lymphocytes and reverse transcribed using random hexamers. The resulting cDNA was PCR-amplified by specific and overlapping pairs of primers designed to amplify three regions of the gp91-phox gene: exons 1-5, 3-9, and 7-13. This strategy detected defective gp91-phox expression in seven patients. The RT-PCR results matched clinical history, biochemical data (nitroblue tetrazolium or superoxide release assay) and available mutation analysis in four cases. In three additional cases, RT-PCR results matched clinical history and biochemical data. In another case, RT-PCR was normal despite a clinical history compatible with CGD and defective respiratory burst. We conclude that this new application of RT-PCR analysis - a simple, economical and rapid method - was appropriate for screening molecular defects in 7 of 8 X-linked CGD patients.Universidade Estadual de Campinas Faculdade de Ciências Médicas Centro de Investigação em Pediatria e Departamentos de Pediatria e FarmacologiaUniversidade de São Paulo Instituto de Ciências Biomédicas Departamento de ImunologiaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PediatriaUniversidade de São Paulo Faculdade de Medicina Departamento de DermatologiaUNIFESP, EPM, Depto. de PediatriaSciEL

Glucose-6-phosphate dehydrogenase deficiency with recurrent infections: case report

OBJECTIVE: To report a case of rare neutrophil functional disorder with clinical and laboratory findings similar to those of chronic granulomatous disease. METHODS: Patient with extremely reduced level of glucose-6-phosphate dehydrogenase and recurrent infections that improved after continuous use of cotrimoxazole. The patient presented leukocytes with defective respiratory burst, similar to what occurs in chronic granulomatous disease. COMMENTS: The diagnosis of glucose-6-phosphate dehydrogenase deficiency in neutrophils should be considered in any patient with hemolytic anemia whose level of G6PD is extremely low or in any patient that presents recurrent infections as differential diagnosis of chronic granulomatous disease.OBJETIVO: relatar a ocorrência de uma deficiência funcional de neutrófilos rara, com quadro clínico e laboratorial semelhante ao da doença granulomatosa crônica. MÉTODOS: relato de caso de paciente com deficiência acentuada da glicose-6-fosfato desidrogenase e infecções de repetição. Realizada pesquisa bibliográfica utilizando as bases de dados Medline e Lilacs, abrangendo o período de 1972 a 2000. RESULTADOS: paciente com nível da glicose-6-fosfato desidrogenase extremamente reduzido e quadro de infeções graves com melhora clínica após uso de cotrimoxazol contínuo. Os leucócitos do paciente apresentam defeito no metabolismo oxidativo, similar ao da doença granulomatosa crônica. CONCLUSÕES: o diagnóstico da deficiência da glicose-6-fosfato desidrogenase em neutrófilos deve ser considerado em qualquer paciente com anemia hemolítica não esferocítica congênita no qual o nível da glicose-6-fosfato desidrogenase esteja anormalmente baixo ou apresente infeções de repetição. É diagnóstico diferencial da doença granulomatosa crônica.Univ. Federal de São Paulo Depto. de Pediatria Disc. de Alergia, Imunologia ClínicaUniv. Federal do Rio de Janeiro Fac. de Medicina Depto. de Medicina PreventivaUNICAMP Faculdade de Ciências Médicas Depto. de PediatriaUniv. de São Paulo Fac. de MedicinaUNIFESP-EPM Depto. de PediatriaUSP Instituto de Ciências Biomédicas Depto. de ImunologiaUFRJ Fac. Med. Depto. de Medicina PreventivaUFRJ Fac. de Medicina Depto. de PediatriaUNIFESP, EPM, Depto. de PediatriaSciEL

Antibody response to pneumococcal capsular polysaccharide vaccine in Down syndrome patients

The majority of children with Down syndrome (DS) tend to have frequent bacterial infections including recurrent respiratory infections. Our objective was to evaluate the production of antibodies to pneumococcal polysaccharide antigens after active immunization in DS subjects. IgG antibodies to pneumococcal serotypes (1, 3, 6B, 9V, and 14) were measured before and 6 weeks after immunization with a 23-valent pneumococcal vaccine (Pneumo23®, Pasteur-Merrieux) in 6- to 13-year-old DS children (N = 17) and in aged-matched normal controls (N = 30). An adequate response was defined as a 4-fold increase over baseline or a post-immunization level of specific pneumococcal serotype antibody> or = 1.3 µg/mL. After immunization, all DS children had an increase in post-immunization levels against all serotypes analyzed. A 4-fold or more increase was observed in all DS children concerning serotypes 1 and 14, in 90% of subjects for serotypes 3 and 9V, and in 65% for serotype 6B. Regarding this increase, 8 of the 17 DS children had an adequate response to all serotypes analyzed, 8/17 patients to 4 serotypes and 1/17 to 3 serotypes. However, when we compared post-immunization levels between DS children and controls, we observed lower levels in the former group (P < 0.05) for all serotypes except serotype 3. We conclude that pneumococcal polysaccharide immunization could be beneficial for these DS children.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PediatriaUniversidade Federal do Ceará Departamento de Toxicologia e Análises ClínicasUniversidade de São Paulo Instituto de Ciências Biomédicas Departamento de ImunologiaUniversidade de São Paulo LIM 36 Faculdade de MedicinaLouisiana State University Health Science Center Department of PediatricsUNIFESP, EPM, Depto. de PediatriaSciEL