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We have evaluated the cellular and humoral immune response to primary respiratory syncytial virus (RSV) infection in young infants. Serum specimens from 65 patients <=12 months of age (39 males and 26 females, 28 cases <3 months and 37 cases > or = 3 months; median 3 3.9 months) were tested for anti-RSV IgG and IgG subclass antibodies by EIA. Flow cytometry was used to characterize cell surface markers expressed on peripheral blood mononuclear cells (PBMC) from 29 RSV-infected children. There was a low rate of seroconversion in children <3 months of age, whose acute-phase PBMC were mostly T lymphocytes (63.0 +/- 9.0%). In contrast, a higher rate of seroconversion was observed in children >3 months of age, with predominance of B lymphocytes (71.0 +/- 17.7%). Stimulation of PBMC with RSV (2 x 10(5) TCID50) for 48 h did not induce a detectable increase in intracellular cytokines and only a few showed a detectable increase in RSV-specific secreted cytokines. These data suggest that age is an important factor affecting the infants' ability to develop an immune response to RSV.

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RESUMO

We have evaluated the cellular and humoral immune response to primary respiratory syncytial virus (RSV) infection in young infants. Serum specimens from 65 patients <=12 months of age (39 males and 26 females, 28 cases <3 months and 37 cases > or = 3 months; median 3 ± 3.9 months) were tested for anti-RSV IgG and IgG subclass antibodies by EIA. Flow cytometry was used to characterize cell surface markers expressed on peripheral blood mononuclear cells (PBMC) from 29 RSV-infected children. There was a low rate of seroconversion in children <3 months of age, whose acute-phase PBMC were mostly T lymphocytes (63.0 ± 9.0 percent). In contrast, a higher rate of seroconversion was observed in children >3 months of age, with predominance of B lymphocytes (71.0 ± 17.7 percent). Stimulation of PBMC with RSV (2 x 10(5) TCID50) for 48 h did not induce a detectable increase in intracellular cytokines and only a few showed a detectable increase in RSV-specific secreted cytokines. These data suggest that age is an important factor affecting the infants' ability to develop an immune response to RSV

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The respiratory viruses are recognized as the most frequent lower respiratory tract pathogens for infants and young children in developed countries but less is known for developing populations. The authors conducted a prospective study to evaluate the occurrence, clinical patterns, and seasonal trends of viral infections among hospitalized children with lower respiratory tract disease (Group A). The presence of respiratory viruses in children's nasopharyngeal was assessed at admission in a pediatric ward. Cell cultures and immunofluorescence assays were used for viral identification. Complementary tests included blood and pleural cultures conducted for bacterial investigation. Clinical data and radiological exams were recorded at admission and throughout the hospitalization period. To better evaluate the results, a non- respiratory group of patients (Group B) was also constituted for comparison. Starting in February 1995, during a period of 18 months, 414 children were included- 239 in Group A and 175 in Group B. In Group A, 111 children (46.4%) had 114 viruses detected while only 5 children (2.9%) presented viruses in Group B. Respiratory Syncytial Virus was detected in 100 children from Group A (41.8%), Adenovirus in 11 (4.6%), Influenza A virus in 2 (0.8%), and Parainfluenza virus in one child (0.4%). In Group A, aerobic bacteria were found in 14 cases (5.8%). Respiratory Syncytial Virus was associated to other viruses and/or bacteria in six cases. There were two seasonal trends for Respiratory Syncytial Virus cases, which peaked in May and June. All children affected by the virus were younger than 3 years of age, mostly less than one year old. Episodic diffuse bronchial commitment and/or focal alveolar condensation were the clinical patterns more often associated to Respiratory Syncytial Virus cases. All children from Group A survived. In conclusion, it was observed that Respiratory Syncytial Virus was the most frequent pathogen found in hospitalized children admitted for severe respiratory diseases. Affected children were predominantly infants and boys presenting bronchiolitis and focal pneumonias. Similarly to what occurs in other subtropical regions, the virus outbreaks peak in the fall and their occurrence extends to the winter, which parallels an increase in hospital admissions due to respiratory diseases.

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OBJECTIVE: To evaluate the frequency of the main respiratory viruses in hospitalized children affected by acute lower respiratory tract disease at a university hospital. METHODS: This is a prospective trial that included two cohorts of hospitalized children in the period from April to July 1996. The groups were selected according to the presence of lower respiratory tract disease on admission: Group A- with acute disease (history of less than 7 days) and B- without present or recent respiratory disease. The parameters for defining lower respiratory tract disease included physical and/or radiological pulmonary changes. Clinical and radiological criteria were established for the classification of lower respiratory tract diseases in group A. Nasopharyngeal swab was collected from all children on admission for viral detection by cellular cultures and direct immunofluorescence. RESULTS: 201 cases were selected, 126 in group A and 75 in group B. Viruses were identified in 71 children from groupA(56.4%) and only in 3 from group B (4.0%). The predominant agent in group A was respiratory syncytial virus, identified in 66 cases; adenovirus (4) and influenza (1) were detected in other patients. In group B two patients with respiratory syncytial virus and one with adenovirus were identified. The patients from group A affected by respiratory syncytial virus were younger (median age 3 months versus 13 months) and more wheezy on physical examination (78.7%) than the other patients of the group (33.3%). This virus was associated to most of the bronchiolitis cases (84%) and to half of the pneumonia cases (46.4%). CONCLUSION: The authors found a significant presence of viruses in the majority of children hospitalized with acute lower respiratory tract disease. The respiratory syncytial virus was the predominant agent identified. These results are similar to others previously reported both in developed and some developing countries. The authors emphasize that the present study evaluated only partially the possibility of simultaneous infection by other pathogens and that the present protocol was conducted during the season with the highest incidence of respiratory syncytial virus.

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The authors present the case of a child diagnosed as having idiopathic pulmonary hemosiderosis at five years of age who had a good clinical outcome at the age of ten years. Initially the patient was treated with prednisone and chloroquine with poor results. When cyclophosphamide was added to prednisone, the patient demonstrated clinical and radiological remission. To date, the patient has been followed for one year without any medication, and has had only one limited episode of hemosiderosis. The authors also suggest that the therapeutic regimen with cyclophosphamide and prednisone may be useful for some selected cases.

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For the 15 years from 1978 to 1992 serologic typing was performed on 124 pneumococcus isolates from children with acute pneumonia. The source of bacteria was material obtained by aspirative pulmonary punction, pleural fluid or blood; 122 capsular antigens representing groups and types could be determined. Of the 122 isolates serogrouped 14, 1, 6, 5, 4, 7, 23, 19 and 4, accounted for 25.4%; 23.8%; 13.1%; 9.0%; 4.9%; 4.9%; 4.1%; 4.1%; 4.1%; respectively, of cases. The currently available 23-valent vaccine would provide protection against 89.3% of identified pneumococci in our study, but because of its poor immunogenicity in children less than 2 years old (73.0%) they would have received reduced protection by the use of this vaccine. The distribution of pneumococci serogroups found in our study has an intermediary pattern in relation to those found at develop countries (6, 14, 18, 19, 23) and developing ones (1, 2, 3, 5, 7, 12, 46). The new conjugate vaccines, with limited number of pneumococcal groups/types, should be analysed before the introduction in different geographic areas.

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Os autores analisaram 19 casos de criancas asmaticas que apresentavam crises espaticas severas apesar da utilizacao domiciliar de aerosol de salbutamol. Os pacientes eram seguidos em ambulatorio especializado. Foram avaliadas as tecnicas de utilizacao do inalador, constatando-se 32 erros. Na continuidade do trabalho foi acoplado espacador ao aerosol e realizado treinamento breve. A avaliacao subsequente da tecnica inalatoria observou apenas 1 erro em todo o grupo.

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Os autores apresentam 13 casos de pneumonia pneumococica aguda em crianca cujo padrao de apresentacao e evolucao mimetizava pneumonia de outras etiologias, em especial, a pneumonia estafilococica. Tecem comentarios sobre a provavel multiplicidade de fatores envolvidos no comportamento anomalo da infeccao pulmomar nestas criancas e sugerem que, em pelo menos sete delas, os pneumococos eram moderadamente resistentes a penicilina. O Streptococcus pneumoniae tem sido considerado, ao longo do tempo, o agente principal das pneumonias bacterianas agudas, de origem comunitaria, fora do periodo neonatal. Em nosso meio, o pneumococo foi identificado em 18 a 35 por cento das pneumonias bacterianas em criancas, em uma serie de trabalhos , sendo o agente etiologico principal em todas as faixas etarias, com excecao do primeiro mes de vida. Antes do advento da antibioticoterapia, a mortalidade de criancas com pneumonia oscilava de 20 a 50 por cento. Esta alta taxa decaiu, drasticamente, para menos de 1 por cento na era antibiotica. A alta eficacia dos antimicrobianos contra este tipo de infeccao, traduzida por rapida melhora clinica e radiologica dos pacientes e a raridade das complicacoes, nao estimularam muitos estudos sobre o assunto....

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