Asian Dust and Pediatric Emergency Department Visits Due to Bronchial Asthma and Respiratory Diseases in Nagasaki, Japan.

BACKGROUND: The adverse health effects of Asian dust (AD) on the respiratory system of children are unclear. We hypothesized that AD events may lead to increased visits by children to emergency medical centers due to bronchial asthma and respiratory diseases, including bronchial asthma. METHODS: We used anonymized data on children receiving primary emergency treatment at Nagasaki Municipal Primary Emergency Medical Center, Japan between March 2010 and September 2013. We used Light Detection and Ranging (LIDAR) data to assess AD exposure and performed time-stratified case-crossover analyses to examine the association between AD exposure and emergency department visits. The main analysis was done with data collected from March through May each year. RESULTS: The total number of emergency department visits during the study period was 756 for bronchial asthma and 5421 for respiratory diseases, and the number of "AD days" was 47. In school children, AD events at lag day 3 and lag day 4 were associated with increased emergency department visits due to bronchial asthma, with odds ratios of 1.837 (95% confidence interval [CI], 1.212-2.786) and 1.829 (95% CI, 1.179-2.806), respectively. AD events were significantly associated with respiratory diseases among preschool children at lag day 0, lag day 1, and lag day 2, with odds ratios of 1.244 (95% CI, 1.128-1.373), 1.314 (95% CI, 1.189-1.452), and 1.273 (95% CI, 1.152-1.408), respectively. These associations were also significant when the results were adjusted for meteorological variables and other air pollutants. CONCLUSIONS: The study findings suggested that AD exposure increases emergency department visits by children.

Does respiratory virus coinfection increases the clinical severity of acute respiratory infection among children infected with respiratory syncytial virus?

BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory infection in children less than 5 years of age. The impact of non-RSV respiratory virus coinfection on the severity of RSV disease is unknown. METHODS: This hospital-based prospective study was conducted in Nagasaki, Japan, on all children less than 5 years of age with acute respiratory infection (ARI) who had undergone a rapid RSV diagnostic test between April 2009 and March 2010. Thirteen respiratory viruses were identified from nasopharyngeal swab samples using a multiplex polymerase chain reaction; polymerase chain reaction-positive samples were considered as confirmed respiratory virus infections. The cases were classified into 3 categories (pneumonia, moderate-to-severe nonpneumonic ARI and mild ARI) according to the findings of the chest radiograph and the hospitalization records. RESULTS: Among 384 cases enrolled, 371 were eligible for analysis, of whom 85 (23%) were classified as pneumonia cases; 137 (37%) as moderate-to-severe nonpneumonic ARI cases and 162 (40%) as mild ARI cases. RSV was detected in 172 cases (61.6%), and 31 cases (18.0%) had double or triple infections with other respiratory viruses. RSV infection was more frequently observed in pneumonia cases (odds ratio [OR]: 2.3; 95% confidence interval [CI]: 1.31-3.9) and moderate-to-severe nonpneumonic ARI cases (OR: 2.95; 95% CI: 1.82-4.78) than in mild ARI cases. The association with moderate-to-severe nonpneumonic ARI cases was stronger with RSV/non-RSV respiratory virus coinfection (adjusted OR: 4.91; 95% CI: 1.9-12.7) than with RSV single infection (adjusted OR: 2.77; 95% CI: 1.64-4.7). CONCLUSIONS: Non-RSV respiratory virus coinfection is not uncommon in RSV-infected children and may increase the severity of RSV disease.

X-linked lymphoproliferative syndrome presenting with systemic lymphocytic vasculitis.

X-linked lymphoproliferative syndrome (XLP) is a rare, often fatal, primary immunodeficiency disease characterized by an abnormal response to Epstein-Barr virus (EBV) infection. The gene responsible for XLP has been identified as SH2D1A/DSHP/SLAM-associated protein (SAP). The major clinical manifestations include fulminant infectious mononucleosis, lymphoproliferative disorder, and dysgammaglobulinemia. Affected males uncommonly present with lymphocytic vasculitis in addition to aplastic anemia. In this study, we describe a Japanese XLP patient who presented with hypogammaglobulinemia following acute EBV-induced infectious mononucleosis in the infancy and later had systemic lymphocytic vasculitis and hemophagocytic lymphohistiocytosis in the adulthood, which resolved by steroid pulse therapy. The patient's SAP gene was found to harbor a missense mutation (His8Asp), presumably resulting in defective expression of SAP in T cells. Biopsy specimens of lung and skin disclosed that CD8+ T cells predominantly infiltrated vascular vessels. However, immunohistochemical examination showed that EBV-infected cells were not identifiable in the vessels. We propose that T-cell-mediated immune dysregulation in XLP can cause vasculitis by EBV infection-unrelated mechanism.