Abstract Objectives: To describe the ontogeny of the immune system and the adaptive mechanisms of the immune system in the neonatal period, with an emphasis on transplacental antibody transport and breastfeeding. Source of data: Non-systematic literature review in the PubMed database. Summary of the findings: The last two decades have witnessed a great advance in the knowledge of the immune system since conception. Several investigation tools have provided insight on phenomena that were previously inadequately understood. Still expanding, the functional and molecular investigation of various aspects of the immune system will make it possible to understand how intra-uterus maternal-fetal exchanges, the maternal microbiota interacting with the fetus and newborn, and the acquisition of immunological competence occur in healthy and disease scenarios. Conclusions: In-depth knowledge of the development of the immune system and of the adaptive mechanisms that allow a safer transition to the extrauterine environment are fundamental components of optimizing maternal and young infant vaccination, as well as the strategies associated with full postnatal development, and the early diagnosis and treatment of innate errors of immunity.

ABSTRACT Introduction: Effective and long-term combined antiretroviral therapy (cART) has decreased morbidity and mortality in HIV-infected individuals. Despite treatment advances, HIV-infected children continue to develop noninfectious conditions, including liver fibrosis. Methods: Cross-sectional study designed to identify liver fibrosis in HIV-infected adolescents and young adults, in an outpatients clinic of Pediatric Infectious Diseases Division at Escola Paulista de Medicina/Universidade Federal de São Paulo (UNIFESP), diagnosed by noninvasive methods (liver elastography–FibroScan®, APRI and FIB4). Variables examined included demographics, clinical, laboratories, HIV treatment. All participants underwent FibroScan® to measure liver parenchyma elasticity. Values equal to above 7.0 kPa were interpreted as the presence of significant liver fibrosis. Two different biomarkers of liver fibrosis were employed: the AST-to-Platelet Ratio Index (APRI) and the Fibrosis-4 score (FIB-4). APRI values above 1.5 have been considered as levels of clinically significant liver fibrosis and FIB-4 values above 3.25 suggested the presence of advanced fibrosis. Results: Between August 2014 and March 2017, the study enrolled 97 patients, age 10–27 years old, fourteen of 97 subjects (14.4%) presented liver stiffness (≥7 kPa) detected by the liver elastography. No patient had APRI> 1.5. No patient had FIB4 value > 3.25. The only isolated laboratory parameter that could be significantly associated with high liver stiffness was thrombocytopenia (p= 0.022, Fisher's exact test). Conclusion: Liver stiffness was identified in 14.4% (14/97) of this cohort by liver elastography. Liver disease in HIV-infected adolescents and young adults manifests itself silently, so should be routinely investigated.

Abstract Background: The reactivation rate of tuberculosis in patients with chronic inflammatory arthritis (CIA) on TNFα inhibitors (TNFi) and baseline negative screening for latent tuberculosis infection (LTBI) is higher than in the general population. Aim: To compare the performance of tuberculin skin test (TST), TST-Booster, ELISPOT (T-SPOT.TB) and QuantiFERON-TB Gold in tube (QFT-IT) to detect LTBI in patients with CIA on TNFi. Patients and methods: A total of 102 patients with CIA [rheumatoid arthritis (RA), n = 40; ankylosing spondylitis (AS), n = 35; psoriatic arthritis (PsA), n = 7; and juvenile idiopathic arthritis (JIA), n = 20] were prospectively followed-up for 24 months to identify incident LTBI cases. Epidemiologic data, TST, T-SPOT.TB, QFT-IT and a chest X-ray were performed at baseline and after 6 months of LTBI treatment. Results: Thirty six percent (37/102) of patients had positive TST or Interferon Gamma Release Assays (IGRAs) tests. Agreement among TST and IGRAs was moderate (k = 0.475; p = 0.001), but high between T-SPOT.TB and QFT-IT (k=0.785; p < 0.001). During the 24-Month follow-up, 15 (18.5%) incident cases of LTBI were identified. In comparison to TST, the IGRAs increased the LTBI diagnosis power in 8.5% (95% CI 3.16-17.49). TST-Booster did not add any value in patients with negative TST at baseline. After 6-Month isoniazid therapy, IGRAs results did not change significantly. Conclusions: Almost 20% of CIA patients had some evidence of LTBI, suggesting higher conversion rate after exposition to TNFi. TST was effective in identifying new cases of LTBI, but IGRAs added diagnostic power in this scenario. Our findings did not support the repetition of IGRAs after 6-Month isoniazid therapy and this approach was effective to mitigate active TB in 2 years of follow-up.

ABSTRACT Background: Pediatric oncology patients (POP) have a high risk of infections due to impaired immunity. Invasive pneumococcal disease (IPD) is an important cause of severe infection in these patients and it is associated with high mortality. This study aimed to evaluate the incidence and risk factors associated with IPD at a Pediatric Oncology Center in Brazil. Methods: This was a retrospective case-control study. All IPD cases in children with cancer from 2005 through 2016 were reviewed. Each case of IPD was matched with two controls from a cohort of patients matched for year of IPD, age and disease in order to assess risk factors. The incidence density was calculated as the number of IPD per 100,000 patients-year. Results: A total of 51 episodes of IPD in 49 patients was identified. All pneumococci were isolated from blood cultures. The median age was five years and 67% were male; mortality rate was 7.8%. The IPD incidence density rate in POP was 311.21 per 100,000 patients-year, significantly higher than the rate in the general pediatric population. Severe neutropenia was the only risk factor associated with IPD, after multivariate conditional logistic regression analysis. Conclusion: Although pneumococcal disease decreased after the introduction of 10-valent pneumococcal vaccine in the Brazilian national immunization schedule in 2010, there was no decrease in the IPD incidence rate in our cohort. A higher coverage rate of pneumococcal vaccination in children in the general population might be necessary to reduce the incidence rate in this high-risk population.

Resumo Objetivos Descrever as características das infecções oportunistas em pediatria em seus aspectos clínicos, bem como a estratégia diagnóstica e o tratamento. Fonte dos dados Revisão de trabalhos de literatura de forma não sistemática na base de dados Pubmed. Síntese dos dados São apresentadas as infecções oportunistas causadas por micobactérias não tuberculosas, fungos, herpervírus e as infecções que acometem indivíduos em uso de imunobiológicos. Por se tratar de doenças graves e de evolução rápida, a suspeita diagnóstica deve ser precoce, associada à clínica do paciente e aos dados de história que apontam para infecções oportunistas. Sempre que possível, amostras de secreções, sangue e outros fluidos e de tecidos devem ser coletadas, com instituição precoce de terapia. Conclusões Apesar da melhoria do diagnóstico de infecções oportunistas nos últimos anos, elas ainda são um desafio para o pediatra pouco habituado a essas infecções. Ele deve fazer a suspeita e iniciar a condução do caso, mas recorrer a especialistas com prática no manejo dessas infecções de modo a propiciar um melhor desfecho para esses pacientes que ainda apresentam alta mortalidade.

Abstract Objectives To describe the characteristics of opportunistic infections in pediatrics regarding their clinical aspects, as well as the diagnostic strategy and treatment. Source of data Non-systematic review of literature studies in the PubMed database. Synthesis of data Opportunistic infections caused by non-tuberculous mycobacteria, fungi, Herpesvirae, and infections affecting individuals using immunobiological agents are analyzed. Because these are severe diseases with a rapid evolution, diagnostic suspicion should be early, associated with the patient's clinical assessment and history pointing to opportunistic infections. Whenever possible, samples of secretions, blood, and other fluids and tissues should be collected, with early therapy implementation. Conclusions Despite the improved diagnosis of opportunistic infections in recent years, they remain a challenge for pediatricians who are not used to these infections. They should raise the suspicion and start treating the case, but should also resort to specialists in the management of these infections to provide a better outcome for these patients, who still have high mortality.

ABSTRACT Introduction: Immune response to vaccination in infants born prematurely may be lower than in infants born at full-term. Some clinical factors might be associated with humoral immune response. Objectives: The objectives of this study were to compare the immune response to measles and varicella vaccination in infants born prematurely with those born at full-term and to analyze factors associated with measles and varicella antibody levels. Methods: Prospective study including two groups of infants aged 12 months. One group of infants born prematurely with birth-weight <1500 g and who were in follow-up at the outpatient clinic for preterm infants at the institution and other group of infants born at full-term. Infants with malformations, primary immunodeficiency diseases, born to HIV-positive mothers or who had received plasma or immunoglobulin transfusions five months before or three weeks after vaccination were excluded. Plasma antibodies were measured by ELISA and factors associated with antibody levels were assessed by linear regression. Results: Sixty-five premature and 56 full-term infants were included. The percentage of immune individuals after vaccination against measles (100% vs. 100%) and varicella (92.5% vs. 93.2%) were similar in both groups, as well as the antibody levels against measles (2.393 vs. 2.412 UI/mL; p = 0.970) and varicella (0.551 vs. 0.399 UI/mL; p = 0.114). Use of antenatal corticosteroids decreased measles antibody levels whereas breastfeeding for more than six months increased varicella antibody levels. Conclusions: Humoral responses to measles and varicella were similar between infants born prematurely and full-term infants. Measles antibody levels were negatively associated with antenatal corticosteroid use; varicella antibodies were positively associated with prolonged breastfeeding.

ABSTRACT Immunological and clinical findings suggestive of some immune dysfunction have been reported among HIV-exposed uninfected (HEU) children and adolescents. Whether these defects are persistent or transitory is still unknown. HEU pediatric population at birth, 12 months, 6-12 years were evaluated in comparison to healthy age-matched HIV-unexposed controls. Plasma levels of LPS, sCD14, cytokines, lymphocyte immunophenotyping and T-cell receptor excision circles (TREC) were assessed. HEU and controls had similar LPS levels, which remained low from birth to 6-12 years; for plasma sCD14, IL-2, IL-6, IL-7, IL-10, IL-12p70, IL-13, IL-17, IFN-γ, TNF-α, G-CSF, GM-CSF and MCP-1, which increased from birth to 12 months and then decreased at 6-12 years; and for TREC/106 PBMC at birth in HEU and controls. By contrast, plasma MIP-1β levels were lower in HEU than in controls (p=0.009) at 12 months, and IL-4 levels were higher in HEU than controls (p=0.04) at 6-12 years. Immune activation was higher in HEU at 12 months and at 6-12 years than controls based on frequencies of CD38+HLA-DR+CD8+T cells (p=0.05) and of CD38+HLA-DR+CD4+T cells (p=0.006). Resting memory and activated mature B cells increased from birth to 6-12 years in both groups. The development of the immune system in vertically HEU individuals is comparable to the general population in most parameters, but subtle or transient differences exist. Their role in influencing clinical incidences in HEU is unknown.

SUMMARY BCG adverse events (BCG-AE) are rare conditions with no well-established treatment. This study aims to describe clinical characteristics and outcome of localized BCG-AE. Children with BCG-AEs who were treated at the Reference Center for Special Immunobiologicals of the Federal University of São Paulo from 2009 to 2011 were included. Patients were followed monthly until 3 months after healing. One hundred and twenty-seven patients with localized BCG-AE were followed: 67 (52.7%) had suppurative lymphadenitis; 30 (23.6%) injection-site abscess; five (3.9%) had enlarged lymph node > 3 cm; four (3.1%) had ulcer > 1 cm; and one (0.8%) had a local bacterial infection. Five patients (3.9%) had more than one BCG-AE simultaneously. Fifteen patients (11.8%) had atypical manifestations: seven wart-like lesions; five BCG reactivations; two other dermatologic lesions and one with vasomotor phenomenon. Isoniazid was used in 96 patients with typical BCG-AE (85.7%) until lesion resolution which took place 3.1 months later (in median); the healing rate was 90.6%. Patients with atypical manifestations had an individual approach. Regarding the outcome, 105/112 patients with typical AE and 13/15 patients with atypical AE had resolution of BCG-AE. Localized BCG-AE caused by BCG Moreau RJ had positive outcome when treated with a short course of isoniazid. Atypical BCG-AE are not infrequent.

SUMMARY This study evaluated the adherence to influenza vaccination among medical students in 2010 and 2011. From August to December 2011, a questionnaire was used to record the influenza vaccination in 2010 and 2011, reasons for acceptance of the influenza vaccine and knowledge of healthcare workers about the influenza vaccine recommendation. One hundred and forty-four students from the 2ndto the 6th years of the medical school were interviewed. A great adherence to pandemic influenza vaccine was noted in 2010, (91% of the students), with "self-protection" being the most common reason cited for vaccination. Other determinants for the vaccination during pandemic were "convenient access to vaccine" and "encouragement by peers and teachers in workplaces and at the university". However, there was a great decay in the acceptance to vaccine in the next influenza season (2011). Only 42% of the students received the vaccine. They claimed "lack of time" and "have forgotten to take the vaccine" as the main reasons. The "knowledge on the recommendation of influenza vaccine to healthcare workers" increased when the students come to attend the last year of the medical school, but that was an insufficient motivator for vaccination. Strategies to increase vaccination should be based on the abovementioned aspects for the adoption of effective measures in both, pandemic and seasonal periods.

Several studies point to the increased risk of reactivation of latent tuberculosis infection (LTBI) in patients with chronic inflammatory arthritis (CIAs) after using tumour necrosis factor (TNF)a blockers. To study the incidence of active mycobacterial infections (aMI) in patients starting TNFa blockers, 262 patients were included in this study: 109 with rheumatoid arthritis (RA), 93 with ankylosing spondylitis (AS), 44 with juvenile idiopathic arthritis (JIA) and 16 with psoriatic arthritis (PsA). All patients had indication for anti-TNFa therapy. Epidemiologic and clinical data were evaluated and a simple X-ray and tuberculin skin test (TST) were performed. The control group included 215 healthy individuals. The follow-up was 48 months to identify cases of aMI. TST positivity was higher in patients with AS (37.6%) than in RA (12.8%), PsA (18.8%) and JIA (6.8%) (p < 0.001). In the control group, TST positivity was 32.7%. Nine (3.43%) patients were diagnosed with aMI. The overall incidence rate of aMI was 86.93/100,000 person-years [95% confidence interval (CI) 23.6-217.9] for patients and 35.79/100,000 person-years (95% CI 12.4-69.6) for control group (p < 0.001). All patients who developed aMI had no evidence of LTBI at the baseline evaluation. Patients with CIA starting TNFa blockers and no evidence of LTBI at baseline, particularly with nonreactive TST, may have higher risk of aMI.

RESUMO Relatamos o caso de uma criança com agamaglobulinemia ligada ao X, sexo masculino, oito anos de idade, que desenvolveu quadro de varicela leve, apesar do tratamento regular com imunoglobulina intravenosa (IVIG). O paciente mantinha níveis adequados de imunoglobulina (IgG) contra varicela, assim como, os últimos lotes de IVIG por ele recebido também apresentavam níveis adequados do anticorpo específico. O caso ilustra que o tratamento regular com IVIG não é suficiente para prevenir a infecção pelo vírus da varicela-zoster.

SUMMARY We describe the case of an eight-year-old boy with X-linked agammaglobulinemia who developed mild varicella despite regular intravenous immunoglobulin (IVIG) therapy. He maintained protective antibody levels against varicella and the previous batches of IVIG that he received had adequate varicella-specific IgG levels. The case illustrates that IVIG may not prevent VZV infection.

Ethnic origin, genetics, gender and environmental factors have been shown to influence some immunologic indices, so that development of reference values for populations of different backgrounds may be necessary. We have determined the distribution of lymphocyte subsets in healthy Brazilian individuals from birth to adulthood. Lymphocyte subsets were determined using four-colour cytometry in a cross-sectional study of 463 human immunodeficiency virus-unexposed children and adults from birth through 49 years of age. Lymphocyte subsets varied according to age, as previously observed in other studies. However, total CD4+ T cell numbers were lower than what was described in the Pediatric AIDS Clinical Trials Group P1009 (PACTG P1009), which assessed an American population of predominantly African and Hispanic backgrounds until the 12-18 year age range, when values were comparable. Na&#239;ve percentages and absolute values of CD8+ T cells, as assessed by CD45RA expression, were also lower than the PACTG P1009 data for all analysed age ranges. CD38 expression on both CD4+ and CD8+ T cells was lower than the PACTG P1009 values, with a widening gap between the two studies at older age ranges. Different patterns of cell differentiation seem to occur in different settings and may have characteristic expression within each population.

lIn 2009, the influenza A (H1N1) virus spread rapidly around the world, causing the first pandemic of the 21st Century. In 2010, there was a vaccination campaign against this new virus subtype to reduce the morbidity and mortality of the disease in some countries, including Brazil. Herein, we describe the clinical and epidemiological characteristics of patients under 19 years of age who were hospitalized with confirmed influenza A (H1N1) infection in 2009 and 2010. We retrospectively reviewed files from the pediatric patients who were admitted to a university hospital with real-time polymerase chain reaction (RT-PCR) confirmed influenza A (H1N1) infection in 2009 and 2010. There were 37 hospitalized patients with influenza A (H1N1) in 2009 and 2 in 2010. In 2009, many of the hospitalized children had an underlying chronic disease and a lower median age than those not hospitalized. Of the hospitalized patients, 78% had a chronic disease, primarily pneumopathy (48%). The main signs and symptoms of influenza were fever (97%), cough (76%), and dyspnea (59%). Complications occurred in 81% of the patients. The median length of hospitalization was five days; 27% of the patients required intensive care, and two died. In 2010, two patients were hospitalized with influenza A (H1N1): one infant with adenovirus co-infection who had received one previous H1N1 vaccine dose and presented with respiratory sequelae and a 2-month-old infant who had a hospital-acquired infection. An impressive reduction in hospital admissions was observed in 2010 when the vaccination campaign took place in Brazil.

INTRODUÇÃO: No Brasil, estudos mostram que a soroprevalência do HTLV entre gestantes varia de 0 a 1,8%. Contudo, esta soroprevalência era desconhecida no Estado do Pará, Brasil. O presente estudo descreve, pela primeira vez, a soroprevalência do HTLV entre gestantes do Estado do Pará, Norte do Brasil. MÉTODOS: 13,382 gestantes foram submetidas à triagem para HTLV durante o pré-natal, e aquelas com sorologia alterada para anti-HTLV foram submetidas ao teste de Western Blot (WB), para confirmar e discriminar portadoras do HTLV-1 e do HTLV-2. RESULTADOS: A soroprevalência do HTLV na população de gestantes foi de 0,3%, sendo o HTLV-1 identificado em 95,3% das pacientes. O perfil demográfico das portadoras do HTLV foi de: mulheres com idade entre 20-40 anos (78,4%); residentes na região metropolitana de Belém (67,6%) e com nível educacional igual ao ensino médio (56,8%). Outras variáveis relacionadas à infecção foram: início das relações sexuais compreendido entre 12-18 anos (64,9%), e ter sido aleitada mais de 6 meses (51,4%). A maior parte das mulheres estudadas teve ao menos duas gestações anteriores (35,1%); e nenhum aborto (70,3%). Co-infecções (sífilis e HIV) foram descritas em 10,8% (4/37) das gestantes. A soroprevalência da infecção pelo HTLV em gestantes atendidas em Unidades Básicas de Saúde do Estado do Pará, Norte do Brasil foi de 0,3% semelhante à descrita em outros estudos brasileiros. As variáveis relacionadas com a infecção são indicadores importantes na identificação de gestantes com maior tendência a soropositividade pelo HTLV, sendo uma estratégia de controle e prevenção, evitando a transmissão vertical.

INTRODUCTION: In Brazil, studies have shown that HTLV seroprevalence among pregnant women varies from 0 to 1.8%. However, this seroprevalence was unknown in the State of Pará, Brazil. The present study describes, for the first time, the HTLV seroprevalence among pregnant women from the State of Pará, Northern Brazil. METHODS: 13,382 pregnant women were submitted to HTLV screening during prenatal care, and those with non-seronegative results to anti-HTLV were submitted to Western blot (WB) test to confirm and separate HTLV-1 and HTLV-2 carriers. RESULTS: HTLV seroprevalence in the population of pregnant women was 0.3%, and HTLV-1 was identified in 95.3% of patients. The demographic profile of HTLV carriers was as follows: women with age between 20 and 40 years old (78.4%); residing in the metropolitan region of Belém, Pará (67.6%); and with educational level of high school (56.8%). Other variables related to infection were as follows: beginning of sexual intercourse between the age of 12 and 18 years old (64.9%) and have being breastfed for more than 6 months (51.4%). Most of the women studied had at least two previous pregnancies (35.1%) and no abortion (70.3%). Coinfections (syphilis and HIV) were found in 10.8% (4/37) of these pregnant women. CONCLUSIONS: Seroprevalence of HTLV infection in pregnant women assisted in basic health units from the State of Pará, Northern Brazil, was 0.3% similar to those described in other Brazilian studies. The variables related to infection were important indicators in identifying pregnant women with a higher tendency to HTLV seropositivity, being a strategy for disease control and prevention, avoiding vertical transmission.