Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Hyun Woong Lee is active.

Publication


Featured researches published by Hyun Woong Lee.


Gut | 2015

Liver injury in acute hepatitis A is associated with decreased frequency of regulatory T cells caused by Fas-mediated apoptosis

Yoon Seok Choi; Jeewon Lee; Hyun Woong Lee; Dong Yeop Chang; Pil Soo Sung; Min Kyung Jung; Jun Yong Park; Ja Kyung Kim; Jung Il Lee; Hana Park; Jae Youn Cheong; Kyung-Suk Suh; Hyung Joon Kim; June Sung Lee; Kyung Ah Kim; Eui Cheol Shin

Objective Foxp3+CD4+CD25+ regulatory T cells (Tregs) control immune responses, but their role in acute viral hepatitis remains elusive. Herein, we investigated alteration in the peripheral blood Treg population during acute hepatitis A (AHA) and its implication in the immune-mediated liver injury. Design The study included 71 patients with AHA, and peripheral blood mononuclear cells (PBMCs) were isolated. The suppressive activity of Treg population was determined by assessing anti-CD3/CD28-stimulated proliferation of Treg-depleted and reconstituted PBMCs. Treg cell frequency, phenotype and apoptosis in PBMCs were analysed by flow cytometry. Results The frequency of circulating Tregs was reduced during AHA. Moreover, the suppressive activity of the total Treg pool in the peripheral blood was attenuated during AHA. Treg frequency and suppressive activity of the Treg population inversely correlated with the serum alanine aminotransferase level. Fas was overexpressed on Tregs during AHA, suggesting their susceptibility to Fas-induced apoptosis. Indeed, increased apoptotic death was observed in Tregs of patients with AHA compared with healthy controls. In addition, agonistic anti-Fas treatment further increased apoptotic death of Tregs from patients with AHA. The decreased Treg frequency and Fas overexpression on Tregs were not observed in other acute liver diseases such as acute hepatitis B, acute hepatitis C and toxic/drug-induced hepatitis. Conclusions The size of the Treg pool was contracted during AHA, resulting from apoptosis of Tregs induced by a Fas-mediated mechanism. Decrease in Treg numbers led to reduced suppressive activity of the Treg pool and consequently resulted in severe liver injury during AHA.


International Journal of Cancer | 2013

Human liver carboxylesterase 1 outperforms alpha‐fetoprotein as biomarker to discriminate hepatocellular carcinoma from other liver diseases in Korean patients

Keun Na; Seul Ki Jeong; Min Jung Lee; Sang Yun Cho; Sun A. Kim; Min Ji Lee; Si Young Song; Hoguen Kim; Kyung Sik Kim; Hyun Woong Lee; Young-Ki Paik

Although alpha‐fetoprotein (AFP) is currently the major serologic biomarker for hepatocellular carcinoma (HCC), it cannot efficiently distinguish this cancer from other forms of liver disease in early diagnosis due to its low sensitivity. The aim of this study is to compare sensitivity and specificity of human carboxylesterase 1 (hCE1) and AFP biomarker. Antibody‐based assays for hCE1 and AFP were used to test both biomarkers with respect to diagnostic efficiency, Youdens index and the area under the curve (AUC) through receiver operating characteristic (ROC) analysis in plasma from 208 patients with HCC (n=57), liver cirrhosis (n=27), chronic hepatitis (n=37), cholangiocarcinoma (n=22), gastric cancer (n=31) and pancreatic cancer (n=34), along with 52 healthy donors (HDs). The levels of hCE1 were significantly higher in patients with HCC than HDs and the other diseases (p<0.005), further verified by AUC values and Youdens index. In the set of HCC versus liver cirrhosis the AUC values were 0.744 (AFP), 0.918 (hCE1) and 0.938 (combination of AFP and hCE1), respectively. These results indicate that hCE1 is not only a more potent and specific marker in distinguishing cancer from liver diseases, in particular cirrhosis, but the combination of hCE1 and AFP shows also synergistic potential for greater sensitivity and specificity in early diagnosis. Therefore the antibody‐based hCE1 assay appears to have high diagnostic efficiency for discriminating HCC from other forms of liver disease. It is now feasible to further validate this novel plasma‐based biomarker in the large cohort we assembled.


Clinical and molecular hepatology | 2013

Clinical features and outcomes of gastric variceal bleeding: retrospective Korean multicenter data

Moon Young Kim; Soon Ho Um; Soon Koo Baik; Yeon Seok Seo; Soo Young Park; Jung Il Lee; Jin-Woo Lee; Gab Jin Cheon; Joo Hyun Sohn; Tae Yeob Kim; Young Suk Lim; Tae Hyo Kim; Tae Hee Lee; S.J. Park; Seung Ha Park; Jin Dong Kim; Sang Young Han; Chang Soo Choi; Eun Young Cho; Dong Joon Kim; Jae Seok Hwang; Byoung Kuk Jang; June Sung Lee; Sang Gyune Kim; Young Seok Kim; So Young Kwon; Won Hyeok Choe; Chang Hyeong Lee; Byung Seok Kim; Jae Young Jang

Background/Aims While gastric variceal bleeding (GVB) is not as prevalent as esophageal variceal bleeding, it is reportedly more serious, with high failure rates of the initial hemostasis (>30%), and has a worse prognosis than esophageal variceal bleeding. However, there is limited information regarding hemostasis and the prognosis for GVB. The aim of this study was to determine retrospectively the clinical outcomes of GVB in a multicenter study in Korea. Methods The data of 1,308 episodes of GVB (males:females=1062:246, age=55.0±11.0 years, mean±SD) were collected from 24 referral hospital centers in South Korea between March 2003 and December 2008. The rates of initial hemostasis failure, rebleeding, and mortality within 5 days and 6 weeks of the index bleed were evaluated. Results The initial hemostasis failed in 6.1% of the patients, and this was associated with the Child-Pugh score [odds ratio (OR)=1.619; P<0.001] and the treatment modality: endoscopic variceal ligation, endoscopic variceal obturation, and balloon-occluded retrograde transvenous obliteration vs. endoscopic sclerotherapy, transjugular intrahepatic portosystemic shunt, and balloon tamponade (OR=0.221, P<0.001). Rebleeding developed in 11.5% of the patients, and was significantly associated with Child-Pugh score (OR=1.159, P<0.001) and treatment modality (OR=0.619, P=0.026). The GVB-associated mortality was 10.3%; mortality in these cases was associated with Child-Pugh score (OR=1.795, P<0.001) and the treatment modality for the initial hemostasis (OR=0.467, P=0.001). Conclusions The clinical outcome for GVB was better for the present cohort than in previous reports. Initial hemostasis failure, rebleeding, and mortality due to GVB were universally associated with the severity of liver cirrhosis.


Journal of Gastroenterology and Hepatology | 2014

Clinical outcomes and prognostic factors of patients with advanced hepatocellular carcinoma treated with sorafenib as first-line therapy: A Korean multicenter study

Sangheun Lee; Beom Kyung Kim; Seung Up Kim; Soo Young Park; Ja Kyung Kim; Hyun Woong Lee; Jun Yong Park; Do Young Kim; Sang Hoon Ahn; Won Young Tak; Young Oh Kweon; Jung Il Lee; Kwan Sik Lee; Hyung Joon Kim; Kwang Hyub Han

Sorafenib is recommended as a standard treatment for advanced hepatocellular carcinoma (HCC). The efficacy and safety of sorafenib as a first‐line therapy in Korean patients with advanced HCC were investigated.


Journal of Immunology | 2013

Antibody-Secreting Cells with a Phenotype of Ki-67low, CD138high, CD31high, and CD38high Secrete Nonspecific IgM during Primary Hepatitis A Virus Infection

Seokchan Hong; Hyun Woong Lee; Dong Yeop Chang; Sooseong You; Jihye Kim; Jun Yong Park; Sang Hoon Ahn; Dongeun Yong; Kwang Hyub Han; Ook Joon Yoo; Eui Cheol Shin

Although studies investigating the nature of Ab-secreting cells (ASCs) during acute infection with influenza or dengue virus found that the ASC response was dominated by virus-specific IgG secretion, the Ag specificity and phenotype of ASCs during primary acute viral infection were not identified. To this end, we investigated the nature of ASCs in direct ex vivo assays from patients with acute hepatitis A caused by primary infection with hepatitis A virus (HAV). We found that the frequency of CD27highCD38high ASCs was markedly increased in the peripheral blood during the acute phase of HAV infection. Moreover, substantial numbers of ASCs were non-HAV–specific and dominantly secreted IgM. We detected HAV-specific ASCs by staining with fluorochrome-tagged HAV-VP1 protein. As compared with HAV-specific ASCs, non-HAV–specific ASCs were Ki-67lowCD138highCD31highCD38high, demonstrating that non-HAV–specific ASCs had a bone marrow plasma cell–like phenotype whereas HAV-specific ASCs had a phenotype typical of circulating plasmablasts. These data suggest that non-HAV–specific ASCs might be mobilized plasma cells from the bone marrow or the spleen, whereas HAV-specific ASCs were newly generated plasmablasts. In this study, we provide evidence that pre-existing plasma cells are released into the circulation and contribute to Ag-nonspecific secretion of IgM during primary HAV infection.


The Korean Journal of Hepatology | 2009

Efficacy of 48-week clevudine therapy for chronic hepatitis B

Min Hwan Kim; Kyung-Ah Kim; June Sung Lee; Hyun Woong Lee; Hyung Joon Kim; Sang Gu Yun; Nam-Hoon Kim; Won Ki Bae; Young Soo Moon

BACKGROUND/AIMS Clevudine is a nucleoside analogue that exhibits potent and sustained antiviral effects as a 24-week therapy for chronic hepatitis B (CHB). This study evaluated the efficacy and viral resistance of a 48-week course of clevudine treatment for CHB. METHODS Data on patients with CHB and detectable serum hepatitis B virus (HBV) DNA who were treated with clevudine for 48 weeks or longer were collected retrospectively for this study. Patients who had taken lamivudine within the 3 years prior to this study were excluded. Serum HBV DNA was measured by polymerase chain reaction hybridization (lower detection limit=316 copies/mL). Serum HBV DNA and biochemical data were analyzed at weeks 24 and 48. Developments of viral breakthrough and resistance to the antiviral drug were also monitored. RESULTS Data from 74 patients (mean age 44 years; M:F=54:20; HBeAg-positive, 47; HBeAg-negative, 27) were included in this study. Ten patients had experienced previous lamivudine treatment. Median HBV DNA at baseline was 6.49 log(10) copies/mL. Median serum HBV DNA reductions from baseline at week 48 were -4.34 log(10) copies/mL (HBeAg-positive, -4.84 log(10) copies/mL; HBeAg-negative, -3.74 log(10) copies/mL). At week 48, serum HBV DNA was not detected in 83.8% of the patients (HBeAg-positive, 76.6%; HBeAg-negative, 96.3%). Normalization of serum alanine aminotransferase levels was achieved in 84.7% of the patients. Viral breakthrough and antiviral resistance developed in two patients at week 48. The development of antiviral resistance was associated with the presence of previous lamivudine treatment and cirrhosis. CONCLUSION A 48-week course of clevudine therapy was highly effective in patients with CHB. The risk of development of resistance to clevudine was increased in patients with previous exposure to lamivudine and cirrhosis.


Journal of Clinical Virology | 2014

Viral evolutionary changes during tenofovir treatment in a chronic hepatitis B patient with sequential nucleos(t)ide therapy

Hyun Woong Lee; Hye Young Chang; Suh Yoon Yang; Hyung Joon Kim

A 54-year-old man diagnosed with HBeAg-positive chronic hepatitis B (CHB) was treated with entecavir (ETV) 1mg/day following an initial unsuccessful lamivudine (LAM) treatment (rtL180M, rtM204V/I). Subsequently, virological breakthrough with ETV mutation (rtT184A/L) developed. The LAM and adefovir combination therapy was followed by virological breakthrough. The therapy had been switched to TDF monotherapy. However, this patient experienced virological breakthrough under TDF with a HBV strain bearing rtL80M, rtL180M, rtM204V/I, rtA200V, rtF221Y, rtS223A, rtT184A/L, rtR153Q, and rtV191I combined mutations without rtA194T mutation. TDF resistance may emerge due to multi-site polymerase mutations rather than single-site polymerase mutation.


PLOS ONE | 2015

Clinical Factors and Viral Load Influencing Severity of Acute Hepatitis A

Hyun Woong Lee; Dong-Yeop Chang; Hong Ju Moon; Hye Young Chang; Eui-Cheol Shin; June Sung Lee; Kyung-Ah Kim; Hyung Joon Kim

Background and Aims Clinical manifestations of hepatitis A virus (HAV) infection vary from mild to fulminant hepatic failure (FHF) in adults. We investigated the relationship between laboratory findings, including viral load, and clinical outcomes in patients with acute hepatitis A (AHA) and evaluated predictive factors for severe acute hepatitis (s-AH). Methods We analyzed the clinical manifestations of AHA in 770 patients. Patients with a prothrombin time (PT) of less than 40% of normal were classified as s-AH and included 4 patients with FHF, 11 patients with acute renal failure, and 3 patients with prolonged jaundice (n = 128). Other patients were defined as mild acute hepatitis (m-AH) (n = 642). Serum samples were obtained from 48 patients with acute hepatitis A. Among them, 20 with s-AH, and 28 with m-AH, were tested for HAV RNA titer. Results In a multivariate analysis, age (HR = 1.042, P = 0.041), peak creatinine (HR = 4.014, P = 0.001), bilirubin (HR = 1.153, P = 0.003), alanine aminotransferase (ALT) (HR = 1.001, P<0.001), initial lactate dehydrogenase (LDH) (HR = 1.000, P = 0.045) and total cholesterol (HR = 0.978, P<0.001) were independent factors for s-AH. Serum HAV RNA was detected in 20/20 (100%) patients with s-AH and 22/28 (78.6%) patients with m-AH. In a multivariate analysis of the 48 patients who were tested for HAV RNA, peak ALT (HR = 1.001, P = 0.004) and HAV RNA titer (HR = 2.076, P = 0.012) were independent factors for s-AH. Conclusions Clinical factors including age, peak creatinine, bilirubin, ALT, initial LDH and total cholesterol were independent factors for s-AH in a multivariate analysis. In particular, HAV load strongly correlated with the severity of hepatitis A.


Intervirology | 2012

Simultaneous Emergence of Entecavir Resistance Mutations in a Nucleoside-Naive Chronic Hepatitis B Patient

Hyun Woong Lee; Hyung Joon Kim; Sun Pyo Hong; Bong Ki Cha; Hye Young Chang; Chang Hwan Choi; Jae Hyuk Do; Jae Gyu Kim; Sae Kyung Chang

Background: Entecavir (ETV) has potent antiviral activity against hepatitis B virus (HBV), and the emergence of drug resistance is rare in nucleoside-naive patients. Resistance requires simultaneous appearance of three mutations which account for the very low resistance profile of ETV. We experienced one case of genotypic ETV resistance with viral rebound during ETV treatment of nucleoside-naive patients with chronic hepatitis B (CHB). Case: A 50-year-old HBV e antigen-positive man received ETV 0.5 mg/day for 120 weeks. The level of HBV DNA was 9.0 log10 copies/ml at baseline, declined to a nadir of 2.7 at week 60 and then rebounded to 6.0 at week 108 and 7.5 at week 120. The serum alanine aminotransferase level did not increase during ETV treatment. The ETV resistance-related substitution (T184A) and lamivudine resistance-related substitutions (L180M and M204V) were detected by sequence analysis at week 96. Conclusions: The three substitutions associated with ETV and lamivudine resistance developed simultaneously without complete suppression in a nucleoside-naive CHB patient after extended therapy. In spite of the extremely rare chance of viral mutation during ETV treatment, treatment-naive patients with high pretreatment viral loads and detectable HBV DNA during treatment should be carefully monitored or undergo targeted surveillance for resistance.


Intervirology | 2008

Clinical course of virologic breakthrough after emergence of YMDD mutations in HBeAg-positive chronic hepatitis B.

Do Young Kim; Sang Hoon Ahn; Hyun Woong Lee; Jun Yong Park; Seung Up Kim; Kwan Sik Lee; Kwang Hyub Han; Chae Yoon Chon

Objective: High rate of resistance to lamivudine is a major problem in treating chronic hepatitis B (CHB) patients. We investigated the course of virologic breakthrough (VB) after emergence of YMDD mutants in CHB patients receiving lamivudine. Methods: Ninety-three consecutive HBeAg-positive CHB patients treated with lamivudine (100 mg/day) who developed YMDD mutants and VB were enrolled. The clinical breakthrough (CB) was defined by elevation of alanine aminotransferase (ALT) >2 times the upper limit of normal. Results: The median age was 47 years, and genotype of hepatitis B virus (HBV) was all C. The median duration of lamivudine administration was 39 months, and median pre-lamivudine ALT and HBV DNA were 165 IU/l and 1.2 × 108 copies/ml. In all patients, CB concurred with VB or appeared some months following VB. When patients were divided into two groups according to time sequence of two breakthroughs – group 1 (VB followed by CB, n = 68) and group 2 (concurrent VB and CB, n = 25) – there was no difference in patient and virologic characteristics between the two groups. The median time from VB to CB was 8 months in group 1. Conclusion: VB might eventually progress to CB in HBeAg-positive patients harboring YMDD mutants with high pretreatment ALT and HBV DNA.

Collaboration


Dive into the Hyun Woong Lee's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge