Expanding the Phenotype of 8p23.1 Deletion Syndrome: Eight New Cases Resembling the Clinical Spectrum of 22q11.2 Microdeletion.

OBJECTIVE: To report the effectiveness of early molecular diagnosis in the clinical management of rare diseases, presenting 8 patients with 8p23.1DS who have clinical features that overlap the phenotypic spectrum of 22q11.2DS. STUDY DESIGN: This report is part of a previous study that aims to provide a precocious molecular diagnosis of the 22q11.2 deletion syndrome in 118 infants with congenital heart disease. To confirm the clinical diagnosis, patients underwent comparative genomic screening by the multiplex ligation-dependent probe amplification (MLPA) assay with the SALSA MLPA probemix kits P064-B2, P036-E1, P070-B2, P356-A1, and P250- B1. Subsequently, the patients performed the genomic microarray using the Infinium CytoSNP-850K BeadChip to confirm the deletion, determine the breakpoints of the deletion, and search for genomic copy number variations. RESULTS: MLPA performed with 3 different kits revealed the 8p23.1 typical deletion involving the PPP1R3B, MSRA, and GATA4 genes in the 5 patients. The array analysis was performed on these 5 patients and 3 other patients (8 patients) who also had clinical suspicion of 22q11 deletion (8 patients) allowed a precise definition of the breakpoints and excluded other genomic abnormalities. CONCLUSIONS: Cytogenomic screening was efficient in establishing a differential diagnosis and ruling out the presence of other concomitant syndromes. The clinical picture of the 8p23.1 deletion syndrome is challenging; however, cytogenomic tools can provide an exact diagnosis and help to clarify the genotype-phenotype complexity of these patients. Our reports underline the importance of early diagnosis and clinical follow-up of microdeletion syndromes.

Microbiological profile in chronic granulomatous disease patients in a single Brazilian primary immunodeficiencies center

Background: Chronic granulomatous disease (CGD) is a rare primary immunodeficiency. Infections of the lungs, skin, lymph nodes, and liver are the hallmark of CGD with frequent initial manifestations of the disease. The aim of the present study was to describe the sites of infections and their causative agents in 38 CGD pediatric patients. Methods: This was a retrospective single-center cohort study comprising CGD patients, and followed for over last 40 years at the Allergy and Immunology Unit of a tertiary hospital in São Paulo, Brazil. Sites of infections and their causative agents were described. Results: A total of 38 patients were included (36 males and 2 females). Median age at the onset of symptoms was 45 days (7 days–7 years) and that at the time of diagnosis was 23 months (1 month–12 years); 31.6% of the parents reported death of relatives during childhood and 21% (8 cases) had another male family member with CDG. The most common infections were pneumonia (81.6%), skin infections (50.0%), adenitis (42.1%), and liver abscess (23.7%). In all, 188 cultures were positive (85.6% for bacteria and 14.4% for fungi). The most prevalent bacterial agents were Staphylococcus sp. (12.4%), Staphylococcus aureus (11.2%), and Klebsiella pneumoniae (9.3%). Aspergillus sp. and Candida sp. were 56% and 22.2% of the isolated fungi, respectively. Mycobacterium tuberculosis was isolated in 5.6% and Mycobacterium bovis in 0.9% (only in 1 patient) of cultures. Conclusion: Staphylococcus sp., Staphylococcus aureus, and Aspergillus sp. were the most frequent agents in this cohort. M. tuberculosis should be considered in endemic areas. Detection of infectious agents drives to find adequate treatment and benefits the evolution of patients with CGD (AU)

Microbiological profile in chronic granulomatous disease patients in a single Brazilian primary immunodeficiency center

Background Chronic granulomatous disease (CGD) is a rare primary immunodeficiency. Infections of lung, skin, lymph nodes, and liver are the hallmark of CGD and frequently the initial manifestation of the disease. The aim of the present paper is to describe the sites of infections and their causative agents in 38 pediatric patients with CGD Methods This retrospective, single-center cohort study included CGD patients followed at the allergy and immunology unit of a tertiary hospital in São Paulo, Brazil over the last 40 years. Sites of infections and their causative agents were described. Results Thirty-eight patients were included (36 males). The median age of onset of symptoms was 45 days (ranging from 7 days–7 years), and the median age at diagnosis was 23 months (ranging from 1 month–12 years). In all, 31.6% of the patients reported a family history of child deaths and 21% (eight cases) had another male family member with CGD. The most common infections were pneumonia (81.6%), skin infections (50.0%), adenitis (42.1%), and liver abscess (23.7%); 188 cultures were positive (85.6% bacteria; 14.4% fungi). The most prevalent bacterial agents were Staphylococcus sp. (12.4%), Staphylococcus aureus (11.2%), and Klebsiella pneumoniae (9.3%). Aspergillus sp. and Candida sp. were 56% and 22.2% of the isolated fungi, respectively. Mycobacterium tuberculosis was isolated in 5.6% and Mycobacterium bovis in one patient (0.9%). Conclusion Staphylococcus sp., Staphylococcus aureus, and Aspergillus sp. were the most frequent agents found in this cohort. M. tuberculosis should be considered in endemic area. Detection of infectious agents drives to the adequate treatment and benefits the evolution of patients with CGD (AU)

Microbiological profile in chronic granulomatous disease patients in a single Brazilian primary immunodeficiency center.

BACKGROUND: Chronic granulomatous disease (CGD) is a rare primary immunodeficiency. Infections of lung, skin, lymph nodes, and liver are the hallmark of CGD and frequently the initial manifestation of the disease. The aim of the present paper is to describe the sites of infections and their causative agents in 38 pediatric patients with CGD. METHODS: This retrospective, single-center cohort study included CGD patients followed at the allergy and immunology unit of a tertiary hospital in São Paulo, Brazil over the last 40 years. Sites of infections and their causative agents were described. RESULTS: Thirty-eight patients were included (36 males). The median age of onset of symptoms was 45 days (ranging from 7 days-7 years), and the median age at diagnosis was 23 months (ranging from 1 month-12 years). In all, 31.6% of the patients reported a family history of child deaths and 21% (eight cases) had another male family member with CGD. The most common infections were pneumonia (81.6%), skin infections (50.0%), adenitis (42.1%), and liver abscess (23.7%); 188 cultures were positive (85.6% bacteria; 14.4% fungi). The most prevalent bacterial agents were Staphylococcus sp. (12.4%), Staphylococcus aureus (11.2%), and Klebsiella pneumoniae (9.3%). Aspergillus sp. and Candida sp. were 56% and 22.2% of the isolated fungi, respectively. Mycobacterium tuberculosis was isolated in 5.6% and Mycobacterium bovis in one patient (0.9%). CONCLUSION: Staphylococcus sp., Staphylococcus aureus, and Aspergillus sp. were the most frequent agents found in this cohort. M. tuberculosis should be considered in endemic area. Detection of infectious agents drives to the adequate treatment and benefits the evolution of patients with CGD.

Severe clinical spectrum with high mortality in pediatric patients with COVID-19 and multisystem inflammatory syndrome.

OBJECTIVES: To assess the outcomes of pediatric patients with laboratory-confirmed coronavirus disease (COVID-19) with or without multisystem inflammatory syndrome in children (MIS-C). METHODS: This cross-sectional study included 471 samples collected from 371 patients (age<18 years) suspected of having severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The study group comprised 66/371 (18%) laboratory-confirmed pediatric COVID-19 patients: 61 (92.5%) patients tested positive on real-time reverse transcription-polymerase chain reaction tests for SARS-CoV-2, and 5 (7.5%) patients tested positive on serological tests. MIS-C was diagnosed according to the criteria of the Center for Disease Control. RESULTS: MIS-C was diagnosed in 6/66 (9%) patients. The frequencies of diarrhea, vomiting, and/or abdominal pain (67% vs. 22%, p=0.034); pediatric SARS (67% vs. 13%, p=0.008); hypoxemia (83% vs. 23%, p=0.006); and arterial hypotension (50% vs. 3%, p=0.004) were significantly higher in patients with MIS-C than in those without MIS-C. The frequencies of C-reactive protein levels >50 mg/L (83% vs. 25%, p=0.008) and D-dimer levels >1000 ng/mL (100% vs. 40%, p=0.007) and the median D-dimer, troponin T, and ferritin levels (p<0.05) were significantly higher in patients with MIS-C. The frequencies of pediatric intensive care unit admission (100% vs. 60%, p=0.003), mechanical ventilation (83% vs. 7%, p<0.001), vasoactive agent use (83% vs. 3%, p<0.001), shock (83% vs. 5%, p<0.001), cardiac abnormalities (100% vs. 2%, p<0.001), and death (67% vs. 3%, p<0.001) were also significantly higher in patients with MIS-C. Similarly, the frequencies of oxygen therapy (100% vs. 33%, p=0.003), intravenous immunoglobulin therapy (67% vs. 2%, p<0.001), aspirin therapy (50% vs. 0%, p<0.001), and current acute renal replacement therapy (50% vs. 2%, p=0.002) were also significantly higher in patients with MIS-C. Logistic regression analysis showed that the presence of MIS-C was significantly associated with gastrointestinal manifestations [odds ratio (OR)=10.98; 95%CI (95% confidence interval)=1.20-100.86; p=0.034] and hypoxemia [OR=16.85; 95%CI=1.34-211.80; p=0.029]. Further univariate analysis showed a positive association between MIS-C and death [OR=58.00; 95%CI=6.39-526.79; p<0.0001]. CONCLUSIONS: Pediatric patients with laboratory-confirmed COVID-19 with MIS-C had a severe clinical spectrum with a high mortality rate. Our study emphasizes the importance of investigating MIS-C in pediatric patients with COVID-19 presenting with gastrointestinal involvement and hypoxemia.

Severe clinical spectrum with high mortality in pediatric patients with COVID-19 and multisystem inflammatory syndrome

OBJECTIVES: To assess the outcomes of pediatric patients with laboratory-confirmed coronavirus disease (COVID-19) with or without multisystem inflammatory syndrome in children (MIS-C). METHODS: This cross-sectional study included 471 samples collected from 371 patients (age<18 years) suspected of having severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The study group comprised 66/371 (18%) laboratory-confirmed pediatric COVID-19 patients: 61 (92.5%) patients tested positive on real-time reverse transcription-polymerase chain reaction tests for SARS-CoV-2, and 5 (7.5%) patients tested positive on serological tests. MIS-C was diagnosed according to the criteria of the Center for Disease Control. RESULTS: MIS-C was diagnosed in 6/66 (9%) patients. The frequencies of diarrhea, vomiting, and/or abdominal pain (67% vs. 22%, p=0.034); pediatric SARS (67% vs. 13%, p=0.008); hypoxemia (83% vs. 23%, p=0.006); and arterial hypotension (50% vs. 3%, p=0.004) were significantly higher in patients with MIS-C than in those without MIS-C. The frequencies of C-reactive protein levels >50 mg/L (83% vs. 25%, p=0.008) and D-dimer levels >1000 ng/mL (100% vs. 40%, p=0.007) and the median D-dimer, troponin T, and ferritin levels (p<0.05) were significantly higher in patients with MIS-C. The frequencies of pediatric intensive care unit admission (100% vs. 60%, p=0.003), mechanical ventilation (83% vs. 7%, p<0.001), vasoactive agent use (83% vs. 3%, p<0.001), shock (83% vs. 5%, p<0.001), cardiac abnormalities (100% vs. 2%, p<0.001), and death (67% vs. 3%, p<0.001) were also significantly higher in patients with MIS-C. Similarly, the frequencies of oxygen therapy (100% vs. 33%, p=0.003), intravenous immunoglobulin therapy (67% vs. 2%, p<0.001), aspirin therapy (50% vs. 0%, p<0.001), and current acute renal replacement therapy (50% vs. 2%, p=0.002) were also significantly higher in patients with MIS-C. Logistic regression analysis showed that the presence of MIS-C was significantly associated with gastrointestinal manifestations [odds ratio (OR)=10.98; 95%CI (95% confidence interval)=1.20-100.86; p=0.034] and hypoxemia [OR=16.85; 95%CI=1.34-211.80; p=0.029]. Further univariate analysis showed a positive association between MIS-C and death [OR=58.00; 95%CI=6.39-526.79; p<0.0001]. CONCLUSIONS: Pediatric patients with laboratory-confirmed COVID-19 with MIS-C had a severe clinical spectrum with a high mortality rate. Our study emphasizes the importance of investigating MIS-C in pediatric patients with COVID-19 presenting with gastrointestinal involvement and hypoxemia.

Primary hypogammaglobulinemia: The impact of early diagnosis in lung complications.

OBJECTIVE:: To describe clinical features, tomographic findings and pulmonary function in pediatric patients with primary hypogammaglobulinemia (PH). METHOD:: A retrospective cohort study of children with PH who received intravenous immunoglobulin (IVIG) and prophylactic antibiotics between 2005 and 2010. Epidemiological and clinical features, computed tomography (CT) findings, and spirometric data were compared, assuming a 5% significance level. RESULTS:: We evaluated 30 patients with PH. After the start of IVIG replacement, there was a decline in the frequency of pneumonia (p<0.001). The 11 patients with bronchiectasis in their first CT scan were older at diagnosis (p=0.001) and had greater diagnostic delay (p=0.001) compared to patients without bronchiectasis. At the end of the study, 18 patients had bronchiectasis and 27 also had other lung disorders, alone or in combination. The Bhalla score was applied to the last CT scan of 16 patients, with a median score of 11 (range 7-21), with a positive correlation between the score and the number of pneumonias after the start of treatment (r=0.561; p=0.024). The score was also correlated with forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) values in 13/16 patients, with negative correlation to FEV1 previously to bronchodilator (r=-0.778; p=0.002) and after bronchodilator (r =-0.837; p<0.001) and FVC (r=-0.773; p=0.002). CONCLUSION:: Pulmonary complications were common in this cohort, despite the decrease in the frequency of pneumonia with treatment. Early investigation of patients with recurrent infections for primary immunodeficiencies can reduce the frequency of these complications. The monitoring of changes in spirometry may indicate the need to carry out radiological investigation.

Primary hypogammaglobulinemia: The impact of early diagnosis in lung complications / Hipogamaglobulinemia primária: o impacto do diagnóstico precoce nas complicações pulmonares

Summary Objective: To describe clinical features, tomographic findings and pulmonary function in pediatric patients with primary hypogammaglobulinemia (PH). Method: A retrospective cohort study of children with PH who received intravenous immunoglobulin (IVIG) and prophylactic antibiotics between 2005 and 2010. Epidemiological and clinical features, computed tomography (CT) findings, and spirometric data were compared, assuming a 5% significance level. Results: We evaluated 30 patients with PH. After the start of IVIG replacement, there was a decline in the frequency of pneumonia (p<0.001). The 11 patients with bronchiectasis in their first CT scan were older at diagnosis (p=0.001) and had greater diagnostic delay (p=0.001) compared to patients without bronchiectasis. At the end of the study, 18 patients had bronchiectasis and 27 also had other lung disorders, alone or in combination. The Bhalla score was applied to the last CT scan of 16 patients, with a median score of 11 (range 7-21), with a positive correlation between the score and the number of pneumonias after the start of treatment (r=0.561; p=0.024). The score was also correlated with forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) values in 13/16 patients, with negative correlation to FEV1 previously to bronchodilator (r=-0.778; p=0.002) and after bronchodilator (r =-0.837; p<0.001) and FVC (r=-0.773; p=0.002). Conclusion: Pulmonary complications were common in this cohort, despite the decrease in the frequency of pneumonia with treatment. Early investigation of patients with recurrent infections for primary immunodeficiencies can reduce the frequency of these complications. The monitoring of changes in spirometry may indicate the need to carry out radiological investigation.

Resumo Objetivo: descrever características clínicas, tomográficas e de função pulmonar em pacientes pediátricos com hipogamaglobulinemia primária (HP). Método: estudo de coorte retrospectivo de crianças com HP que recebiam gamaglobulina endovenosa (GEV) e antibiótico profilático entre 2005 e 2010. As características epidemiológicas, clínicas, os achados de tomografia e espirometria foram comparadas adotando níveis de significância de 5%. Resultados: foram avaliados 30 pacientes com HP. Após o início da reposição de GEV, houve redução da frequência de pneumonias (p<0,001). Os 11 pacientes que apresentavam bronquiectasias na primeira tomografia computadorizada (TC) eram mais velhos ao diagnóstico (p=0,001) e tiveram maior atraso no diagnóstico (p=0,001) quando comparados aos pacientes sem bronquiectasias. Ao final do estudo, 18 pacientes apresentavam bronquiectasias e 27/30 também apresentaram outras alterações pulmonares, isoladas ou concomitantes. O escore de Bhalla foi aplicado à última TC de 16/30 pacientes, com mediana do escore de 11 (variação 7-21), com correlação positiva entre o escore e o número de pneumonias após o início do tratamento (r=0,561; p=0,024). O escore foi ainda correlacionado com valores de volume expiratório forçado no primeiro segundo (VEF1) e capacidade vital forçada (CVF) obtidos por espirometria de 13/16 pacientes, com correlação negativa com VEF1 pré- (r=-0,778; p=0,002) e pós-broncodilatador (r=-0,837; p<0,001) e CVF (r=-0,773; p=0,002). Conclusão: complicações pulmonares foram frequentes nesta coorte, apesar da diminuição na frequência de pneumonias com o tratamento. A investigação precoce de pacientes com infecções de repetição para imunodeficiências primárias pode reduzir a frequência dessas complicações. A monitorização de alterações na espirometria pode indicar a necessidade de investigação radiológica.

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 T-cell 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.

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.

Minimal concentration of human IgM and IgG antibodies necessary to protect mice from challenges with live O6 Escherichia coli.

This work evaluated the ability of human anti-lipopolysaccharide O6 IgM and IgG antibodies to protect mice challenged with Escherichia coli serotype O6 : K2ac. Purified IgM-effluent, purified IgG, pools of normal human serum (NHS), or control group were injected into mice 18 h before challenges with O6 E. coli. Interleukin 6 and tumor necrosis factor alpha were quantified in the sera of test and control groups. All mice receiving purified IgM-effluent (66.6 mg L(-1) of anti-lipopolysaccharide O6 IgM antibodies) and NHS survived. Purified IgG (1.1 mg L(-1) of anti-lipopolysaccharide O6 IgG antibodies) protected 87.5% of the animals. The control group showed no protective ability. The minimal concentration of anti-lipopolysaccharide O6 IgM antibodies, able to protect 50% of the animals was 33.3 mg L(-1) of purified IgM-effluent, whereas purified IgG was able to protect 50% of the animals with only 1.1 mg L(-1) of anti-lipopolysaccharide O6 IgG antibodies. Serum from animals pretreated with purified IgM-effluent and purified IgG before challenges with lipopolysaccharide O6 did not have detectable pro-inflammatory cytokines. Hepatocytes of the control group were completely invaded by bacteria, whereas none was found in animals pretreated with purified IgM-effluent and purified IgG. Higher concentrations of anti-lipopolysaccharide O6 IgM antibodies as compared to anti-lipopolysaccharide O6 IgG antibodies were needed to protect mice from challenges with E. coli O6 serotype.

Passive immunity acquisition of maternal anti-enterohemorrhagic Escherichia coli (EHEC) O157:H7 IgG antibodies by the newborn.

Enterohaemorrhagic Escherichia coli (EHEC) strains are among the main causes of haemorrhagic colitis (HC) and haemolytic-uremic syndrome (HUS) in industrialised countries. In Brazil, EHEC have been detected in the faeces of patients with non-bloody diarrhoea, though an association between EHEC and HUS has been detected recently. These observations suggest that there is a pre-existing immunity triggered by the contact with EHEC and other categories of bacteria, such as EPEC, that share similar virulence factors and to which our population is highly exposed. Our aim was to evaluate the placental transfer of IgG antibodies reactive to EHEC O157:H7 antigens. We evaluated 28 paired maternal and cord sera for the presence of IgG against EHEC O157:H7 protein antigens and IgG and IgM to O157 LPS employing ELISA and IB technique. Total IgG and IgM level analyses were also made. Anti-EHEC O157:H7 and anti-LPS O157 IgG antibody levels in cord sera were equivalent to those of their maternal sera. A good correlation between the mothers' anti-LPS O157 IgM and total IgM levels was found. Anti-LPS O157 IgM levels were higher than anti-LPS O157 IgG levels in the same samples, and anti-LPS IgM antibodies were not detected in cord sera. Identical patterns of recognition of bacterial protein antigens by specific IgG were found in the paired samples and the recombinant purified variable region of gamma intimin was specifically recognized by one paired maternal and cord sample. In conclusion, although the antibody profile varied among individuals, all paired cord and maternal serum samples showed an identical recognition pattern, indicating an efficient placental transfer of IgG antibodies reactive to EHEC O157:H7 antigens.

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.

Human colostrum contains IgA antibodies reactive to colonization factors I and II of enterotoxigenic Escherichia coli.

Diarrhea is an important cause of morbidity and mortality amongst infants of low socio-economic levels in developing countries and in travelers who visit such areas. Enterotoxigenic E. coli strains express two sets of virulence-associated factors: enterotoxins (heat-stable toxins or heat-labile toxins) and colonization factors. Studies have shown that breast-feeding protects infants against infectious diseases, such as diarrhea, as it presents a great variety of immunological components. The aim of this study was to analyze the reactivity of immunoglobulin A from human colostrum to colonization factor antigens I and II. The colostrum ability in preventing enterotoxigenic E. coli adhesion to Caco-2 cells was also evaluated. Colostrum samples were collected from 32 healthy women, and a human colostrum pool was prepared. Enterotoxigenic E. coli strains expressing colonization factor antigens I and II were utilized. The colostrum pool and individual samples showed variable antienterotoxigenic E. coli immunoglobulin A titers, that were reactive with colonization factor antigen I and CS1/CS3 (colonization factor antigen II). The human colostrum pool and individual samples inhibited enterotoxigenic E. coli colonization factor antigen I and II adhesion to Caco-2 cells, at variable levels, and this ability was a result of immunoglobulin A antibodies reactive to these colonization factors. The immunoglobulin A-depleted pool lost this inhibitory ability. As bacterial adhesion is the initial mechanism of enterotoxigenic E. coli infection, breast-feeding could protect the offspring against diarrhea caused by this agent.

Colostrum from healthy Brazilian women inhibits adhesion and contains IgA antibodies reactive with Shiga toxin-producing Escherichia coli.

UNLABELLED: Although Shiga toxin-producing Escherichia coli (STEC) has been isolated in Brazil, severe manifestations of the infection, such as haemorrhagic colitis and haemolytic-uraemic syndrome, are extremely rare in our population. Enteropathogenic Escherichia coli (EPEC) is the main aetiological agent of acute infantile diarrhoea in Brazil. There are many similarities between STEC and EPEC, such as the ability to produce attaching and effacing (A/E) lesions and some virulence-associated factors. Our aim was to investigate the presence of anti-STEC antibodies in healthy people living in an EPEC endemic area. Colostrum samples collected from 51 women living in low socio-economic conditions were analysed. Two STEC strains: O111:H- (Stx1) and O157:H7 (Stx2), and one EPEC strain (O111:H-) were used in the bacterial adhesion assays to HEp-2 cells, in the Stx1 and Stx2 cytotoxicity assays on Vero cells, in immunoblotting and in ELISA assays. All the samples strongly inhibited the adhesion of the three strains and contained SIgA antibodies reactive with antigens of EPEC O111:H-, STEC O111:H- and STEC O157:H7, mainly STEC and EPEC 94 kDa adhesin intimin. High titres of anti-LPS O111 antibodies were found in many samples. Nevertheless, the cytotoxic effect of both Stx1 and Stx2 on Vero cells was not neutralised by any sample. CONCLUSION: Our results suggest that Brazilian people may be exposed to Shiga toxin-producing Escherichia colimore frequently than previously thought or alternatively there may be a cross reactive immunity between enteropathogenic Escherichia coliand Shiga toxin-producing Escherichia coli.

Early acquisition of serum and saliva antibodies reactive to enteropathogenic Escherichia coli virulence-associated proteins by infants living in an endemic area.

Enteropathogenic Escherichia coli (EPEC) is the most common etiological agent of acute diarrhea among infants living in poor social conditions in Brazil and other developing countries. This infection is rare in breast-fed infants, as well as in children older than 2 years. Over the past few years, our group has attempted to identify antibodies to EPEC virulence proteins in human milk and to establish the in vitro protective role of these antibodies. In the present study, we report the identification of antibodies to EPEC virulence proteins in sera and saliva from children of different ages, living in slums in the city of São Paulo, Brazil. Using EPEC and bacterial constructs (pET) for immunoblotting (IB) analysis, antibodies reacting to the main adhesins (intimin, bundle-forming pilli) and cell-signaling proteins (EPEC secreted proteins - Esp A, Esp B) were detected in sera from adults and children older than 1 year. Almost all children older than 1 year presented recognition patterns similar to those of adults in IB assays for serum IgG and secretory IgA antibodies, using EPEC outer membrane and other antigenic preparations. As previously observed for human milk, all samples from adults and older children recognized the 94 kDa molecular weight adhesin intimin strongly. In most children, previous EPEC symptomatic diarrhea could not be confirmed; however, almost all of them have presented one or more diarrhea episodes during their lifetime. These results suggest that reduction of EPEC infection frequency after 2 years of age may be associated with the development of anti-EPEC antibody repertoires.