• IMMUNE NETWORK
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• v.7 no.4
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• pp.186-196
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• 2007

Background: Although IL-12 has been widely accepted to playa central role in the control of pathogen infection, the use of recombinant IL-12 (rIL-12) as a vaccine adjuvant has been known to be ineffective because of its rapid clearance in the body. Methods: To investigate the effect of sustained release of IL-12 in vivo in the peptide and protein vaccination models, rIL-12 was encapsulated into poly ($A_{DL}$-lactic-co-glycolic acid) (PLGA). Results: We found that codelivery of IL-12-encapsulated microspheres (IL-12EM) could dramatically increase not only antibody responses, but also antigen-specific $CD4^+\;and\;CD8^+$ T cell responses. Enhanced immune responses were shown to be correlated with protective immunity against influenza and respiratory syncytial virus (RSV) virus challenge. Interestingly, the enhancement of $CD8^+$ T cell response was not detectable when $CD4^+$ T cell knockout mice were subjected to vaccination, indicating that the enhancement of the $CD8^+$ T cell response by IL-12EM is dependent on $CD4^+$ T cell "help". Conclusion: Thus, IL-12EM could be applied as an adjuvant of protein and peptide vaccines to enhance protective immunity against virus infection.

• Pediatric Infection and Vaccine
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• v.19 no.3
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• pp.162-167
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• 2012

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in infants. Life-threatening RSV infection is often reported in young children and immunocompromised hosts. Since there is no report on ribavirin therapy for RSV pneumonia in pediatric cancer patients in Korea, we report one case of RSV pneumonia that developed in an infant with acute lymphoblastic leukemia (ALL). Despite administration of oral ribavirin and intravenous immunoglobulin, the patient's respiratory distress worsened and admission to an intensive care unit was necessary. Chest x-ray showed multifocal consolidation, pneumothorax, and pneumomediastinum. Treatment with aerosolized ribavirin led to significant clinical improvement. The role of aerosolized ribavirin is still controversial, but it might have a therapeutic potential for severe RSV pneumonia in children with leukemia.

• Tuberculosis and Respiratory Diseases
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• v.67 no.2
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• pp.135-139
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• 2009

Human metapneumovirus (hMPV) is a recently recognized human respiratory pathogen, which is known to be associated with upper and lower respiratory tract infections mainly in children, immunocompromised patients, and the elderly. The clinical manifestations of hMPV infections are similar to those of the human respiratory syncytial virus infection, which range from mild upper respiratory tract infection to severe bronchiolitis and pneumonia. Recently, hMPV has come to be thought of as the cause a similar spectrum of disease in adults as that seen in children; however, most of the reports of hMPV infections have focused on infection in children. We report a case of severe hMPV pneumonia requiring mechanical ventilation in an immunocompetent adult in Korea.

• Clinical and Experimental Pediatrics
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• v.52 no.3
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• pp.330-338
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• 2009

Purpose : The causes of acute lower respiratory tract infection (ALRTI) are mostly attributable to viral infection, including respiratory syncytial virus (RSV), parainfluenza virus (PIV), influenza virus A/B (IFV A/B), or adenovirus (ADV). Several Korean studies reported human metapneumovirus (hMPV) as a common pathogen of ALRTI. However, studies on seasonal distribution and clinical differences relative to other viruses are insufficient, prompting us to perform this study. Methods : From November 2006 to October 2007, we tested nasopharyngeal aspiration specimens in children hospitalized with ALRTI with the multiplex reverse transcriptase-polymerase chain reaction to identify 6 kinds of common pathogen (hMPV, RSV, PIV, IFV A/B, and ADV). We analyzed positive rates and clinical features by respiratory chart review. Results : We detected 38 (8.4%) hMPV-positive cases out of 193 (41.8%) virus-positive specimens among 462 patients. HMPV infection prevailed from March to June with incidence peaking in April. HMPV-positive patients were aged 15 years (76.3%), and the ratio of boys to girls was 1.2:1. The median age was 27 months. HMPV primarily caused pneumonia (76.3 %) (P=0.018). Average hospitalization of HMPV-associated ALRTI patients was 5.8 days. In addition, they showed parahilar peribronchial infiltration (100%) on chest X-ray, normal white blood cell count (73.7%), and negative C-reactive protein (86.8 %) (P>0.05). All hMPV-positive patients recovered without complication. Conclusion : HMPV is a common pathogen of ALRTI in Korean children, especially in 1-5 year olds, from March to May. Immunocompetent children diagnosed with hMPV-associated ALRTI may have a good prognosis.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.258-266
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• 1998

Purpose : Cases of adenoviral penumonia with rapidly progressive clinical course were experienced. We reviewed these patients in viewpoint of clinical manifestation and adenoviral serotypes. Methods : Culture and indirect immunofluorescence for respiratory viruses including respiratory syncytial virus, influenza virus, parainfluenza virus, adenovirus was done with nasopharyngeal aspirates from patients who admitted due to respiratory infections in Fatima Hospital, Masan from Nov. 1996 to Jul. 1997. Cultured adenovirus was serotyped by both neutralization and hemagglutination inhibition test. Medical records were reviewed for 5 patients with respiratory failure from adenovirus was isolated and serotyped. Results : The total number of examined patients was 460 patients. We isolated respiratory viruses in 143(30.9%) patients. Adenovirus was isolated from 66 out of 143(46.2%) patients. During Jan 1997 to May 1997, five patients with ages of 18 days to 11 months who were infected by adenovirus and had high fever with dyspnea and required assisted mechanical ventilation. One patients discharged against doctor's advice then died. Two of four patients had complications of disseminated intravascular coagulation; two had bronchiolitis obliterans. Two isolates were serotype 7, and one was serotype 5, and two were untyped. Conclusion : Severe pneumonia caused by serotype 7 continued to occur in 1997 following the epidemic in 1996, and severe pneumonia may also be caused by serotype 5 and other serotypes.

• Clinical and Experimental Pediatrics
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• v.51 no.8
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• pp.834-841
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• 2008

Purpose : This study was perfomed to analyze in detail the viral etiology of acute lower respiratory tract infections (ALRI) in Cheunan, Korea by multiplex RT-PCR, including human rhinovirus (hRV) and newly identified viruses such as human metapneumovirus (hMPV) and human coronavirus (HCoV-OC43, HCoV-229E/NL63). Method : Nasopharyngeal aspirates (NPA) were collected from 863 hospitalized children with ALRI on the first day of admission at Soonchunhyang University Cheonan Hospital and analyzed by multiplex RT-PCR from December 2005 to November 2006. Results : Viral agents were detected from 474 subjects (54.9%). The identified viral pathogens were hRV 9.2%, hMPV 6.8%, HCoV-229E/NL63 1.4%, and HCoV-OC43 2.1%. Coinfections with ${\geq}2$ viruses were observed in 108 patients (22.8%). The major period of viral ALRI was the first year of life. Clinical diagnoses of viral ALRI were pneumonia (59.5%), bronchiolitis (24.7%), tracheobronchitis (11.4%), and croup (4%). The most common causes of bronchiolitis was respiratory syncytial virus B (RSV B), whereas hMPV, hRV, HCoV-229E/NL63, and HCoV-OC43 were commonly found in patients with pneumonia. The number of hMPV infections peaked between March and May 2006. HCoV-OC43 was prevalent from November to February 2006, whereas HCoV-229E and hRV were detected throughout the year. Conclusion : Although the study was confined to one year, hMPV was not detected during winter and peaked between March and April, which was not consistent with previous studies'. This present study indicates that HCoV is a less common respiratory pathogen in cases of ALRI in Korean children

• Clinical and Experimental Pediatrics
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• v.51 no.7
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• pp.729-735
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• 2008

Purpose : Chlamydia trachomatis is one of the most common sexually transmitted diseases and is also a cause of pneumonia in infants. Respiratory infections by respiratory viruses are also common for infants. The objectives of this study were to identify the clinical manifestations and to determine the prevalence of C. trachomatis respiratory infections and coinfections by respiratory viruses in infants younger than 6 months of age. Methods : For this study, we enrolled 6 months or younger infants who were admitted to the Dankook University Hospital between January 2002 and July 2007, with respiratory symptoms. Nasopharyngeal aspirates or throat swabs were collected within s d of hospitalization and C. trachomatis was detected using polymerase chain reaction (PCR). Patients who tested positive underwent multiplex PCR for respiratory viruses. Results : A total of 690 patients underwent chlamydial PCR testing and 36 (5.2%) had positive results. Of the 36, 28 (78%) were male; 30 were vaginally delivered. From the 36 patients positive for C. trachomatis, 26 underwent multiplex respiratory viral PCR; 12 were coinfected with viruses. Respiratory syncytial virus (RSV) was the most frequent pathogen that was detected in 6 patients. Increased C-reactive protein and fever were significant in patients coinfected with respiratory viruses. Conclusion : C. trachomatis can infected in infants delivered by cesarean section as well as in 6 months old or younger infants. Infant with C. trachomatis respiratory infections can also be coinfected with respiratory infection also coinfected with respiratory viruses. Further studies are needed to better understand the prevalence rates of the this infection and its coinfection rate with respiratory viruses.

• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.101-109
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• 2021

Purpose: Common human coronaviruses (HCoVs) are relatively understudied due to the mild nature of HCoV infection. Given the lack of local epidemiology data on common HCoVs, we aimed to describe clinical and epidemiological characteristics of common HCoVs in children. Methods: Respiratory viral test results from 9,589 respiratory samples from Seoul National University Children's Hospital were analyzed from January 2015 to December 2019. Viral detection was done by the multiplex reverse transcription polymerase chain reaction. Demographics and clinical diagnosis were collected for previously healthy children tested positive for HCoVs. Results: Of the 9,589 samples tested, 1 or more respiratory viruses were detected from 5,017 (52.3%) samples and 463 (4.8%) samples were positive for HCoVs (OC43 2.8%, NL63 1.4%, 229E 0.7%). All 3 types co-circulated during winter months (November to February) with some variation by type. HCoV-OC43 was the most prevalent every winter season. HCoV-NL63 showed alternate peaks in late winter (January to March) and early winter (November to February). HCoV-229E had smaller peaks every other winter. Forty-one percent of HCoV-positive samples were co-detected with additional viruses; human rhinovirus 13.2%, respiratory syncytial virus 13.0%, influenza virus 4.3%. Common clinical diagnosis was upper respiratory tract infection (60.0%) followed by pneumonia (14.8%), croup (8.1%), and bronchiolitis (6.7%). Croup accounted for 17.0% of HCoV-NL63-positive children. Conclusions: This study described clinical and epidemiological characteristics of common HCoVs (OC43, NL63, 229E) in children. Continuing surveillance, perhaps by adding HKU1 in the diagnostic panel can further elucidate the spectrum of common HCoV infections in children.

• Clinical and Experimental Pediatrics
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• v.46 no.3
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• pp.230-235
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• 2003

Purpose : Lower respiratory tract infections in infant and young children are often due to a virus, especially the Respiratory syncytial(RS) virus. Chest X-ray findings in bronchiolitis and bronchopneumonia are different. The radiographic hallmark of bronchiolitis is pulmonary hyperinflation and similar to that of bronchial asthma. Bronchiolitis is predisposed to later development of bronchial asthma. To evaluate the difference of immuno-pathophysiology between bronchiolitis and bronchopneumonia, we measured $IFN-{\gamma}$(Th1 cytokine), IL-5(Th2 cytokine) and ECP. We also investigated whether X-ray findings in infants with viral infected respiratory disease are useful in predicting the development of asthma. Methods : We measured IL-5, ECP, $IFN-{\gamma}$ levels in serum from 21 infants with bronchiolitis and 21 infants with bronchopneumonia and 16 infants without pulmonary viral diseases. Results : IL-5 levels of bronchiolitis and bronchopneumonia were significantly higher than those of the control(P=0.02, P=0.042). IL-5 levels of bronchiolitis were higher than those of bronchopneumonia but there was no significant difference. $IFN-{\gamma}$ levels of bronchopneumonia were higher than those of bronchiolitis but there was no significant difference. ECP levels of bronchiolitis and bronchopneumonia were higher than those of the control but only those of bronchiolitis were significantly higher than those of the control(P=0.045). IL-5 and ECP levels did not show any significant correlation in bronchiolitis, bronchopneumonia and control groups. Conclusion : We cannot prove the distinct differences in serum Th1/Th2 cytokine profiles between bronchiolitis and bronchopneumonia in infants. These results suggest that the different findings on chest X-ray between bronchiolitis and bronchopneumonia could not be a predictor of later development of asthma.

• Clinical and Experimental Pediatrics
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• v.49 no.7
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• pp.763-768
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• 2006

Purpose : We investigated the risk of aspiration using the lipid-laden macrophage index(LLMI) from laryngeal lavages in infants with bronchiolitis. Methods : Laryngeal lavages from 22 infants with acute bronchiolitis caused by respiratory syncytial virus(RSV) were evaluated during the acute stage. Repeat studies were performed at 3 to 4 weeks after the initial study(remission stage). Lavage cell counts and differentials were determined. The amount of lipid per single macrophage was evaluated and the LLMI was determined by evaluating 100 cells. Comparisons between acute stage and remission stage were made. Twenty-four hour pH monitoring(pHm) was performed in 12 patients. Results : The total cell number was significantly higher in the acute stage compared with the remission stage(P<0.05). The LLMIs in the acute stage were significantly higher than those in the remission stage(P<0.05). The neutrophils percentage of laryngeal lavage correlated with the LLMI(r=0.69, P<0.001). Four children had positive pHm recordings(pH-positive infants) and eight had negative pHm recordings(pH-negative infants). The pH-positive infants had higher LLMI and higher neutrophils percentage than those of the pH-negative infants(P<0.05). Conclusion : These findings suggest that there is a transient increased risk of aspiration during bronchiolitis. The LLMI from laryngeal lavage may be a useful marker for pulmonary aspiration in infants with bronchiolitis.