Both CD4+ and CD8+ Lymphocytes Participate in the IFN-γ Response to Filamentous Hemagglutinin from Bordetella pertussis in Infants, Children, and Adults

Infant CD4+ T-cell responses to bacterial infections or vaccines have been extensively studied, whereas studies on CD8+ T-cell responses focused mainly on viral and intracellular parasite infections. Here we investigated CD8+ T-cell responses upon Bordetella pertussis infection in infants, children, and adults and pertussis vaccination in infants. Filamentous hemagglutinin-specific IFN-γ secretion by circulating lymphocytes was blocked by anti-MHC-I or -MHC-II antibodies, suggesting that CD4+ and CD8+ T lymphocytes are involved in IFN-γ production. Flow cytometry analyses confirmed that both cell types synthesized antigen-specific IFN-γ, although CD4+ lymphocytes were the major source of this cytokine. IFN-γ synthesis by CD8+ cells was CD4+ T cell dependent, as evidenced by selective depletion experiments. Furthermore, IFN-γ synthesis by CD4+ cells was sometimes inhibited by CD8+ lymphocytes, suggesting the presence of CD8+ regulatory T cells. The role of this dual IFN-γ secretion by CD4+ and CD8+ T lymphocytes in pertussis remains to be investigated

Pandemic A/H1N1v influenza 2009 in hospitalized children: a multicenter Belgian survey

<p>Abstract</p> <p>Background</p> <p>During the 2009 influenza A/H1N1v pandemic, children were identified as a specific "at risk" group. We conducted a multicentric study to describe pattern of influenza A/H1N1v infection among hospitalized children in Brussels, Belgium.</p> <p>Methods</p> <p>From July 1, 2009, to January 31, 2010, we collected epidemiological and clinical data of all proven (positive H1N1v PCR) and probable (positive influenza A antigen or culture) pediatric cases of influenza A/H1N1v infections, hospitalized in four tertiary centers.</p> <p>Results</p> <p>During the epidemic period, an excess of 18% of pediatric outpatients and emergency department visits was registered. 215 children were hospitalized with proven/probable influenza A/H1N1v infection. Median age was 31 months. 47% had ≥ 1 comorbid conditions. Febrile respiratory illness was the most common presentation. 36% presented with initial gastrointestinal symptoms and 10% with neurological manifestations. 34% had pneumonia. Only 24% of the patients received oseltamivir but 57% received antibiotics. 10% of children were admitted to PICU, seven of whom with ARDS. Case fatality-rate was 5/215 (2%), concerning only children suffering from chronic neurological disorders. Children over 2 years of age showed a higher propensity to be admitted to PICU (16% vs 1%, p = 0.002) and a higher mortality rate (4% vs 0%, p = 0.06). Infants less than 3 months old showed a milder course of infection, with few respiratory and neurological complications.</p> <p>Conclusion</p> <p>Although influenza A/H1N1v infections were generally self-limited, pediatric burden of disease was significant. Compared to other countries experiencing different health care systems, our Belgian cohort was younger and received less frequently antiviral therapy; disease course and mortality were however similar.</p

Isolated tracheoesophageal fistula in a 10-year-old girl.

Isolated tracheoesophageal fistula (H-TOF) is a rare type of tracheoesophageal anomaly and is in most cases diagnosed in the neonatal period because of choking and cyanosis during feeding. Diagnosis may be delayed even until adulthood because of nonspecific and sometimes intermittent symptoms, and because false-negative results of all diagnostic tools are not uncommon. We report a 10-year-old child with H-TOF, whose symptoms had nearly disappeared completely between the ages of 4 and 10 years. Diagnosis was only possible after the recurrence of the symptoms at the time of an episode of bronchitis, profound interrogation of the child's medical history, and questioning of the results of a former diagnostic work-up. In this article, we discuss the potential pitfalls in both clinical diagnosis and diagnostic work-up.Case ReportsJournal Articleinfo:eu-repo/semantics/publishe

Latent tuberculosis in a newborn: diagnostic challenges.

In countries where the incidence of tuberculosis is low, perinatal tuberculosis is seldom diagnosed. With increasing numbers of human immunodeficiency virus-infected people and increasing immigrant population from high tuberculosis incidence countries, one might expect perinatal tuberculosis to become more frequent. Early recognition of newborns at risk for perinatal tuberculosis infection is of utmost importance to prevent disease by chemoprophylaxis. We describe a case of latent perinatal tuberculosis infection in a newborn infected from a mother with extrapulmonary primary tuberculosis. Tuberculin skin test was negative, and latent tuberculosis infection was eventually diagnosed by specific immunological tests. We discuss the difficulties in diagnosis of recent tuberculosis infection in neonates and infants, and the risk factors for vertical transmission of tuberculosis, which need to be taken into account in considering the need for chemoprophylaxis in the newborn. Although perinatal TB infection is a rare condition and diagnosis is difficult due to poor diagnostic testing in pregnancy and newborns, a high index of suspicion is needed to limit the diagnostic delay and to avoid progression to perinatal TB disease.JOURNAL ARTICLESCOPUS: ar.jinfo:eu-repo/semantics/publishe

The burden of invasive pneumococcal disease in children with underlying risk factors in North America and Europe

Background: Characterisation of risk groups who may benefit from pneumococcal vaccination is essential for the generation of recommendations and policy. Methods: We reviewed the literature to provide information on the incidence and risk of invasive pneumococcal disease (IPD) in at-risk children in Europe and North America. The PubMed database was searched using predefined search terms and inclusion/exclusion criteria for papers reporting European or North American data on the incidence or risk of IPD in children with underlying medical conditions. Results: Eighteen references were identified, 11 from North America and 7 from Europe, with heterogeneous study methods, periods and populations. The highest incidence was seen in US children positive for human immunodeficiency virus infection, peaking at 4167 per 100,000 patient-years in 2000. Studies investigating changes in incidence over time reported decreases in the incidence of IPD between the late 1990s and early 2000s. The highest risk of IPD was observed in children with haematological cancers or immunosuppression. Overall, data on IPD in at-risk children were limited, lacking incidence data for a wide range of predisposing conditions. There was, however, a clear decrease in the incidence of IPD in at-risk children after the introduction of 7-valent pneumococcal conjugate vaccine into immunisation programmes, as previously demonstrated in the general population. Conclusion: Despite the heterogeneity of the studies identified, the available data show a substantial incidence of IPD in at-risk children, particularly those who are immunocompromised. Further research is needed to determine the true risk of IPD in at-risk children, particularly in the post-PCV period, and to understand the benefits of vaccination and optimal vaccination schedules

Specific memory B cells to 3 Bordetella pertussis antigens after cellular or acellular vaccine, or after whooping cough during childhood

info:eu-repo/semantics/nonPublishe

IFN-g responses to mycobacterial antigens in Mycobacterium tuberculosis-infected young children.

info:eu-repo/semantics/nonPublishe

Milk protein and Oil-Red-O staining of alveolar macrophages in chronic respiratory disease of infancy

International audienceAspiration is a suspected cause of chronic respiratory disease in infants. We assessed the probability of aspiration by immunocytochemical staining of alveolar macrophages for milk proteins (α-lactalbumin and β-lactoglobulin) and compared these findings with the Oil-Red-0 staining score. Broncho-alveolar lavage (BAL), 24-hour esophageal pH-measurement and/or gastro-esophageal scintigraphy were performed in 111 children. Seventy nine patients were enrolled. Ten exclusively soya milk formula fed children served as a control group. Individual scores, expressed as the mean percentage of positive staining macrophages counted by 3 blinded authors were made. Relying on the control group, a positive score was defined as a value higher than 1%. A positive score was found in 26% (18/69). Forty four percent (8/18) of them had positive gastro-esophageal reflux (GER) tests. In 61% (11/18) a concomitant diagnosis of laryngo-/tracheomalacia was made. A positive score was found in 48% (11/23) of patients with laryngo-/ tracheomalacia, compared to 15% (7/46) in infants with normal laryngeal and tracheal anatomy. No correlation was found between the immunocytochemical staining score for milk proteins and the Oil-Red-0 staining score. We conclude that assuming the 1% criterion, persistent respiratory symptoms were associated with a positive immunostaining score, suggestive for aspiration, in 26% of infants, in 48% in case of concomitant laryngo- and/or tracheomalacia and in 15% of infants with normal laryngeal and tracheal anatomy. No correlation was found between the immunocytochemical staining score for cow milk proteins and the Oil-Red-O staining scor