You-Sook Youn

Catholic University of Korea, Seoul, Seoul, South Korea

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Publications (8)14.33 Total impact

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    Article: The clinical characteristics of steroid responsive nephrotic syndrome of children according to the serum immunoglobulin E levels and cytokines.
    You Sook Youn, Han Hyuk Lim, Jae Ho Lee
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    ABSTRACT: The nephrotic syndrome (NS) is characterized by the favorable response to glucocorticoid therapy and the development of NS may be associated with dysfunctional immune systems. In order to investigate the serum immunoglobulin E (IgE) levels and cytokines activity in pediatric NS, the total of 32 steroid responsive NS patients and 5 healthy controls were enrolled in this study. All patients were divided into two groups according to the initial serum IgE levels, such as normal and high IgE group, and their clinical characteristics were evaluated. In addition, serum levels of interleukin (IL)-4, IL-5, IL-10 and transforming growth factor (TGF)-β were compared and correlated with serum albumin, proteinuria by means of disease severity, and cytokines. In the high IgE group, the higher comorbidity of allergic diseases and relapsing rate, the longer duration of steroid therapy before initial remission, and the higher serum IL-4 and IL-5 levels were found. In all patients, initially higher serum levels of IL-4 and IL-5 declined to normal levels after steroid therapy, whereas the serum IL-10 levels showed no significant difference between nephrotic phase (heavy proteinuria) and remission phase (no proteinuria) of NS. The serum TGF-β levels of the nephrotic phase were significantly lower than those of remission phase or control group, and returned to normal control levels after steroid therapy. This study indicates that initial IgE level is associated with steroid responsiveness and disease severity, and cytokine activities may also be related to the pathogenesis of pediatric steroid responsive NS.
    Yonsei medical journal 07/2012; 53(4):715-22. · 0.77 Impact Factor
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    Article: Pandemic 2009 H1N1 virus infection in children and adults: A cohort study at a single hospital throughout the epidemic.
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    ABSTRACT: In 2009, there was an influenza pandemic in South Korea. The aim of this study was to evaluate the epidemiological, clinical and laboratory characteristics of this infection in children and adults. We evaluated the epidemiologic characteristics of patients infected with the 2009 H1N1 influenza A virus (4,463 patients, age range from 2 mo to 86 y), and the clinical and laboratory findings of 373 inpatients (80/217 children, ≤ 15 y, had pneumonia and 36/156 adults, > 16 y, had pneumonia) in a single hospital during the epidemic. The majority of infected patients (94%) were less than 40 y, and greater than 90% of cases occurred during a two-month period. The rates of admission and pneumonia were 8.4% (373/4,463) and 2.5% (116/4,463), respectively. The rates of admission and pneumonia, total duration of fever, the frequency of underlying diseases, and the values of C-reactive protein and erythrocyte sedimentation rate tended to increase as age increased; highest rates were found in the ≥ 65 y group. Pneumonia was founded more boys than girls in children, but more female than male in adults. The adult patients with pneumonia had higher leukocyte counts with lower lymphocyte differentials than the group without pneumonia, as shown in children group. Our results suggest that the immunologic reaction to viral insults may be associated with age, sex and underlying diseases, and that unknown herd immunity may affect populations. The patients with underlying diseases, especially in older patients may have immunologic insufficiency that is associated with immunologic consumption by the underlying diseases.
    International Archives of Medicine 03/2012; 5(1):13.
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    Article: Mycoplasma pneumoniae pneumonia in children.
    You-Sook Youn, Kyung-Yil Lee
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    ABSTRACT: Mycoplasma pneumoniae (MP), the smallest self-replicating biological system, is a common cause of upper and lower respiratory tract infections, leading to a wide range of pulmonary and extra-pulmonary manifestations. MP pneumonia has been reported in 10 to 40% of cases of community-acquired pneumonia and shows an even higher proportion during epidemics. MP infection is endemic in larger communities of the world with cyclic epidemics every 3 to 7 years. In Korea, 3 to 4-year cycles have been observed from the mid-1980s to present. Although a variety of serologic assays and polymerase chain reaction (PCR) techniques are available for the diagnosis of MP infections, early diagnosis of MP pneumonia is limited by the lack of immunoglobulin (Ig) M antibodies and variable PCR results in the early stages of the infection. Thus, short-term paired IgM serologic tests may be mandatory for an early and definitive diagnosis. MP infection is usually a mild and self-limiting disease without specific treatment, and if needed, macrolides are generally used as a first-choice drug for children. Recently, macrolide-resistant MP strains have been reported worldwide. However, there are few reports of apparent treatment failure, such as progression of pneumonia to acute respiratory distress syndrome despite macrolide treatment. The immunopathogenesis of MP pneumonia is believed to be a hyperimmune reaction of the host to the insults from MP infection, including cytokine overproduction and immune cell activation (T cells). In this context, immunomodulatory treatment (corticosteroids or/and intravenous Ig), in addition to antibiotic treatment, might be considered for patients with severe infection.
    Korean Journal of Pediatrics 02/2012; 55(2):42-7.
  • Article: Assessment of intravenous immunoglobulin non-responders in Kawasaki disease.
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    ABSTRACT: The authors compared pre-treatment and post-treatment characteristics of 206 prospectively enrolled patients with Kawasaki disease (KD) responsive to intravenous immunoglobulin (IVIG) with those of 23 (10% of total) IVIG non-responders. Demographic characteristics were similar in both groups. Compared to IVIG responders, non-responders had a longer total duration of fever and a higher incidence of coronary artery lesions. Prior to IVIG, non-responders had higher neutrophil differential and C-reactive protein, and lower cholesterol. 24 hours after the IVIG infusion, a total leucocyte count >13.1×10(9)/l, neutrophil differential >51% and total protein <72 g/l showed reasonable sensitivity (91%, 91% and 64%, respectively) and specificity (89%, 76% and 78%, respectively) as independent characteristics of non-response to IVIG. Laboratory parameters before and shortly after IVIG may reflect the severity of inflammation in KD patients and assist in informing further management.
    Archives of Disease in Childhood 11/2011; 96(11):1088-90. · 2.88 Impact Factor
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    Article: Epidemiological and clinical characteristics of childhood pandemic 2009 H1N1 virus infection: an observational cohort study.
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    ABSTRACT: There was a pandemic influenza around the world in 2009 including South Korea since last pandemic occurred four decades ago. We aimed to evaluate the epidemiological and clinical characteristics of this infection in childhood. We evaluated the epidemiologic characteristics of all the subjects infected with the 2009 H1N1 influenza A virus (2,971 patients, ≤ 15 years of age), and the clinical and laboratory findings of the inpatients (217 patients, 80 had pneumonia) between 1 September 2009 and 31 January 2010 in a single hospital throughout the epidemic. The age distribution of all the subjects was relatively even. Over 90% of cases occurred during a two-month period. Two hundred and five patients (94.5%) received oseltamivir within 48 h of fever onset, and 97% of inpatients defervesced within 48 h of medication. The group with pneumonia included more males than females, and had higher leukocytes counts with lower lymphocyte differentials than the group without pneumonia. The white blood cell count and lymphocyte differential were associated with the severity of pneumonia. Corticosteroid treatment for severe pneumonia patients was highly effective in preventing disease progression. Children of all ages affected with even rates of infection, but males were predominant in pneumonia patients. Pneumonia patients showed lymphopenia and its severity was associated with the severity of illness. Our results suggest that the mechanism of lung injury in 2009 H1N1 virus infection may be associated with the host immune response.
    BMC Infectious Diseases 08/2011; 11:225. · 3.12 Impact Factor
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    Article: Early corticosteroid treatment for severe pneumonia caused by 2009 H1N1 influenza virus.
    Critical care (London, England) 03/2011; 15(2):413. · 4.61 Impact Factor
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    Article: Difference of clinical features in childhood Mycoplasma pneumoniae pneumonia.
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    ABSTRACT: M. pneumoniae pneumonia (MP) has been reported in 10-40% of community-acquired pneumonia cases. We aimed to evaluate the difference of clinical features in children with MP, according to their age and chest radiographic patterns. The diagnosis of MP was made by examinations at both admission and discharge and by two serologic tests: the indirect microparticle agglutinin assay (>or=1:40) and the cold agglutinins titer (>or=1:32). A total of 191 children with MP were grouped by age: <or=2 years of age (29 patients), 3-5 years of age (81 patients), and >or=6 years of age (81 patients). They were also grouped by pneumonia pattern: bronchopneumonia group (96 patients) and segmental/lobar pneumonia group (95 patients). Eighty-six patients (45%) were seroconverters, and the others showed increased antibody titers during hospitalization. Among the three age groups, the oldest children showed the longest duration of fever, highest C-reactive protein (CRP) values, and the most severe pneumonia pattern. The patients with segmental/lobar pneumonia were older and had longer fever duration and lower white blood cell (WBC) and lymphocyte counts, compared with those with bronchopneumonia. The patient group with the most severe pulmonary lesions had the most prolonged fever, highest CRP, highest rate of seroconverters, and lowest lymphocyte counts. Thrombocytosis was observed in 8% of patients at admission, but in 33% of patients at discharge. In MP, older children had more prolonged fever and more severe pulmonary lesions. The severity of pulmonary lesions was associated with the absence of diagnostic IgM antibodies at presentation and lymphocyte count. Short-term paired IgM serologic test may be mandatory for early and definitive diagnosis of MP.
    BMC Pediatrics 01/2010; 10:48. · 1.88 Impact Factor
  • Article: Mycoplasma pneumoniae pneumonia, bacterial pneumonia and viral pneumonia.
    Jornal de pediatria 86(6):448-50. · 1.07 Impact Factor