Objective:To investigate the effect of TCF1+CD8+T cells on the prognosis of nasopharyngeal carcinoma(NPC)pa-tients undergoing immunotherapy.Methods:A retrospective study was conducted on 108 NPC patients admitted to Anyang Cancer Hospital from January 2018 to April 2020.Pathological findings and clinical data were collected,and multiple immunofluorescence staining was utilized to detect TCF1+CD8+T cell levels in tumor tissue.Cell counts and the proportion of positive cells were measured,and the optimal cut-off value was determined using a time-dependent receiver operating characteristic(ROC)curve.Patients were clas-sified into high expression group and low expression group according to the cut-off value.The general information and survival status were compared between two groups,and univariate and multivariate Cox regression analysis were performed to screen the influencing factors of patient prognosis.Results:The optimal cut-off value was determined using ROC curve.A cut-off value of 0.34%for TCF1+CD8+T cell area under the curve(AUC)=0.653 resulted in a sensitivity of 73.5%and a specificity of 43.7%.Based on the opti-mal cut-off value,33 patients with TCF1+CD8+T cell beyond 0.34%were included in high expression group,and the remaining 75 pa-tients were included in low expression group.The proportion of TCF1+CD8+T cells was(0.43±0.09)%in high expression group and(0.21±0.08)%in low expression group.Comparison of general data yielded that the gender,age,body mass index(BMI),clinical stage,and pathological classification showed no statistical difference between two groups(P>0.05),while the percentage of patients with T stage of T3 and T4,N stage of N2 and N3,and M stage of M1 in high expression group were smaller than that in low expression group(P<0.05).The 24-month survival rate was 81.82%(27/33)in high expression group and 74.67%(56/75)in low expression group,with no statistical difference between two groups(χ2=0.658 8,P=0.417 0).Univariate and multivariate Cox regression analysis found that T stage,N stage and M stage were independent risk factors affecting the prognosis of patients,and TCF1+CD8+T expression was a protective factor.ROC curve indicated that the AUC,sensitivity and specificity of TCF1+CD8+T expression in predicting death of NPC patients undergoing immunotherapy was 0.674,69.7%and 65.3%,while the AUC,sensitivity and specificity of TCF1+CD8+T ex-pression combined with TNM stage in predicting death was 0.809,75.8%and 84.0%,respectively.Conclusion:NPC patients with higher proportion of TCF1+CD8+T cells and lower TNM stage have higher 24-month survival rate after immunotherapy,and the above parameters are of great predictive value for patient prognosis.

Objective:To investigate the effect of TCF1+CD8+T cells on the prognosis of nasopharyngeal carcinoma(NPC)pa-tients undergoing immunotherapy.Methods:A retrospective study was conducted on 108 NPC patients admitted to Anyang Cancer Hospital from January 2018 to April 2020.Pathological findings and clinical data were collected,and multiple immunofluorescence staining was utilized to detect TCF1+CD8+T cell levels in tumor tissue.Cell counts and the proportion of positive cells were measured,and the optimal cut-off value was determined using a time-dependent receiver operating characteristic(ROC)curve.Patients were clas-sified into high expression group and low expression group according to the cut-off value.The general information and survival status were compared between two groups,and univariate and multivariate Cox regression analysis were performed to screen the influencing factors of patient prognosis.Results:The optimal cut-off value was determined using ROC curve.A cut-off value of 0.34%for TCF1+CD8+T cell area under the curve(AUC)=0.653 resulted in a sensitivity of 73.5%and a specificity of 43.7%.Based on the opti-mal cut-off value,33 patients with TCF1+CD8+T cell beyond 0.34%were included in high expression group,and the remaining 75 pa-tients were included in low expression group.The proportion of TCF1+CD8+T cells was(0.43±0.09)%in high expression group and(0.21±0.08)%in low expression group.Comparison of general data yielded that the gender,age,body mass index(BMI),clinical stage,and pathological classification showed no statistical difference between two groups(P>0.05),while the percentage of patients with T stage of T3 and T4,N stage of N2 and N3,and M stage of M1 in high expression group were smaller than that in low expression group(P<0.05).The 24-month survival rate was 81.82%(27/33)in high expression group and 74.67%(56/75)in low expression group,with no statistical difference between two groups(χ2=0.658 8,P=0.417 0).Univariate and multivariate Cox regression analysis found that T stage,N stage and M stage were independent risk factors affecting the prognosis of patients,and TCF1+CD8+T expression was a protective factor.ROC curve indicated that the AUC,sensitivity and specificity of TCF1+CD8+T expression in predicting death of NPC patients undergoing immunotherapy was 0.674,69.7%and 65.3%,while the AUC,sensitivity and specificity of TCF1+CD8+T ex-pression combined with TNM stage in predicting death was 0.809,75.8%and 84.0%,respectively.Conclusion:NPC patients with higher proportion of TCF1+CD8+T cells and lower TNM stage have higher 24-month survival rate after immunotherapy,and the above parameters are of great predictive value for patient prognosis.

Objective:Taking emergency department (ED) as a starting point, to analyze the epidemiological characteristics and mortality risk factors of sepsis, and to provide evidences for ED to carry out the strategy of "three early and two lower" for sepsis.Methods:Based on the ED and inpatient medical record management information platform of Tianjin Medical University Gernal Hospital, adult ED patients with sepsis from January 1, 2017 to December 31, 2020 were included according to the third international consensus definitions for sepsis and septic shock in 2016 and the consensus of Chinese experts on early prevention and blocking of sepsis in 2020. The epidemiological characteristics of patients were retrospectively analyzed. Chi-square test was used to compare the difference of age, sex, hospitalization times, length of stay, hospitalization cost and infection location between dead patients and survival patients, and a stepwise logistic regression model was used to analyze the influencing factors of mortality in hospitalized patients with ED sepsis.Results:A total of 7 494 patients with sepsis in ED were included in this study, and the annual and monthly component ratios varied from 3.8‰ to 6.1‰ and 2.0‰ to 9.0‰, respectively. The main characteristics of patients with sepsis in ED were as follows: 40-69 years old (46.0%), male (59.0%), mostly diagnosed with sepsis (96.8%), mainly treated with urban health insurance (59.6%), and ED diagnosis and treatment fees of 2 000-8 000 Yuan (51.1%). The mortality of hospitalized patients with ED sepsis was 24.4% and that of hospitalized patients with septic shock was 28.8%. The main characteristics of hospitalized patients with ED sepsis were as follows: most of them were male (56.2%) patients over 70 years old (56.0%), most of them were diagnosed with sepsis (94.0%) and hospitalized for the first time (76.0%), the median hospitalization time was 15 d, most of them were hospitalized under urban health insurance (65.2%), and the median hospitalization fees was 47 000 Yuan. The risk factors of death were influenced by age and length of stay. Patients aged 70 years or older had a higher risk of death than those aged from 18 to 39 years, and patients with a length of stay of more than 7 d had a lower risk of death than those with a length of stay of shorter than 7 d. The primary infection focus were mainly respiratory and urinary systems, while the death rate of patients with hematological and abdominal infections was relatively high, and the difference was statistically significant ( P<0.01). Respiratory and abdominal infections were risk factors for death in patients with ED sepsis. Conclusions:The composition ratio of sepsis in ED patients is not regular in time, so vigilance of sepsis in elderly men and patients with respiratory system, blood system, urinary system and abdominal infections should be constantly raised. Patients with sepsis who are older, hospitalized more frequently, hospitalized for a shorter time, and infected in the respiratory system or abdomen have a higher risk of death.

Objective: To summarize the diagnosis and treatment of biliary pancreatic duct dilatation. Methods: The retrospective and descriptive study was conducted. The clinical data of 22 patients with biliary pancreatic duct dilatation who were admitted to Renji Hospital of Shanghai Jiaotong University School of Medicine between October 2013 to September 2017 were collected. There were 6 males and 16 females, aged from 33 to 82 years, with an average age of 66 years. Surgical exploration was decided according to clinical symptoms, results of laboratory test and imaging examinations. For patients with space occupying lesions, surgical procedure was selected based on results of pathological examination. Patients without surgical exploration or space occupying lesions were allocated into follow-up. Observation indicators: (1) surgical exploration; (2) relationship of clinical symptoms and preoperative examinations with surgical exploration positive for space occupying lesions; (3) surgical treatment; (4) follow-up. Follow-up using outpatient examination was performed on patients up to October 2018. Follow-up was performed on patients with positive surgical exploration to detect postoperative complications.For patients with positive results of imaging examinations, no jaundice, normal laboratory indicators or mild abnormality, liver function, tumor markers and B-ultrasound were re-examined each month, and computed tomography (CT) and magnetic resonance imaging (MRI) was performed once every 3 months. Surgical exploration was performed when total bilirubin (TBil) or tumor markers showed a progressive increase. Follow-up was performed on patients with negative results of imaging examination, jaundice, and mildly elevated CA19-9. TBil and CA19-9 were re-examined monthly, and if they were progressively elevated, patients were transferred to surgical exploration. For patients with negative results of imaging examination, no symptoms, and negative laboratory test, liver function, tumor markers, and B-ultrasound were re-examined once every 3 months, and enhanced CT and MRI were re-examined once every 6 months within one year. Follow-up was performed once every 6 months during the second year, and once a year after two years. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was analyzed using the t test. Count data were descibed as absolute numbers, and they were analyzed using the chi-square test under R×C chart or Fisher exact probability. Results: (1) Surgical exploration: of 22 patients, 11 underwent surgical exploration, and 11 underwent follow-up. Of the 11 patients with surgical exploration, 4 were positive for space occupying lesions including 1 of false negative, and 7 were negative for space occupying lesions. (2) Relationship of clinical symptoms and preoperative examinations with surgical exploration positive for space occupying lesions. ① Relationship of clinical symptoms and laboratory test with surgical exploration positive for space occupying lesions: juandice was significantly associated with surgical exploration positive for space occupying lesions (P<0.05), and elevated TBil and DBil were significantly associated with surgical exploration positive for space occupying lesions (χ²=0, 0, P<0.05), with a sensitivity of 75.0% and specificity of 100.0%. ② Relationship between imaging examination and surgical exploration positive for space occupying lesions: results of CT, MRI, endoscopic retrograde cholangio-pancreatography, endoscopic ultrasonography, PET-CT, and combined imaging examinations had no significant association with surgical exploration positive for space occupying lesions (χ²=0, 0.77, 0, 0, 1.00, 0, 0, 0, 0, P>0.05). PET-CT had no significant association with surgical exploration positive for space occupying lesions (P>0.05). ③ Relationship of imaging examination and laboratory test with surgical exploration positive for space occupying lesions: positive imaging examination combined with elevated TBil and CA19-9 was significantly associated with surgical exploration positive for space occupying lesions (P<0.05), with a sensitivity of 50.0% and specificity of 100.0%. ④ Relationship of preoperative diameters of biliary ducts and pancreatic ducts with surgical exploration positive for space occupying lesions: of 22 patients, the diameters of biliary ducts and pancreatic ducts were (13.8±4.3)mm and (4.6±1.5)mm for patients with positive surgical exploration, (13.0±2.8)mm and (3.5±0.5)mm for patients with negative surgical exploration, (11.6±2.4)mm and (3.2±0.4)mm for patients with follow-up, respectively, showing no significant difference between them (t=0.22, 0.36, P>0.05). (3) Surgical treatment: 9 of 11 patients with surgical exploration followed the standard procedure. Of the 9 patients, 4 were found space-occupying lesions at the choledocho-pancreatico-duodenal junction (3 undergoing pancreaticoduodenectomy and 1 undergoing duodenal papilla partial resection), 5 with negative exploration underwent common bile duct incision and T-tube drainage (one patient was unable to pinch the T-tube one month after operation and detected obstruction at the lower end of the bile duct by radiography, and was confirmed pancreatic head cancer by reoperation 3 months after the first operation). Two patients didn′t follow the exploratory procedure, and underwent the child operation only based on the preoperative imaging findings, without intraoperative pathological examination. Postoperative pathological examination showed chronic ampulla and chronic pancreatitis, respectively. (4) Follow-up: 22 patients were followed up for 12-60 months, with a median follow-up time of 36 months. Two of 11 patients with surgical exploration had postoperative gastroplegia, 1 had bile leakage, 1 had incisional infection, and they were improved after symptomatic treatment. Four patients undergoing surgeries for positive exploration had no recurrence during follow-up. Of 5 patients with negative exploration undergoing common bile duct incision and T-tube drainage, 1 was confirmed pancreatic head cancer and underwent pancreaticoduodenectomy, 4 were removed T-tube after by T-tube cholangiography at 2 months after surgery. During the follow-up, no positive signs showed in laboratory test or imaging examination. No recurrence occurred in the two patients undergoing pancreaticoduodenectomy. Of 11 patients with follow-up, 10 had abdominal pain before surgery, including 3 with pain during follow-up and 7 with symptoms disappeared. There was no abnormalities in the laboratory test. Conclusions The positive imaging examinations combined with jaundice and elevated CA19-9 is an absolute indication for surgical exploration in patients with biliary duct dilatation. Those patients who do not meet this criteria should be distributed into the follow-up. If no positive pathological results were obtained during the operation, the surgery should be terminated and the patients should be transferred into follow-up. The reckless biliary anastomosis or biliary stents placement is opposed.

Objective To explore the potential neural mechanism of adolescent schizophrenia by analysis of the resting state functional connectivity(rs-FC) network of posterior cingulate gyrus(PCC) with functional magnetic resonance imaging (fMRI).Methods Twenty-one first-episode medication-naive adolescent patients with schizophrenia were recruited from outpatients and inpatients in the Sichuan Mental Health Center from December 2016 to January 2018,and 21 gender-,age-and education-matched healthy ones were as control.The illness severity was estimated by PANSS and Psychotic Symptom Rating Scales (PSYRAT).All subjects was scanned by resting-state brain fMRI.The PCC was defined as a seed region of interest(ROI) after the imaging preprocessing,and the functional connectivity between seed region and other brain regions were calculated after the imaging data preprocessing.Statistical analysis of image data was processed by REST software.Results Data of 19 patients and 21 healthy volunteers were included in statistical analysis after realignment.Compared to the control group,the patients group exhibited increased PCC rs-FC (P＜0.05,AlphaSim-corrected for multiple comparisons,cluster size＞40) in two brain regions including the left orbital part of inferior frontal gyrus extended to the left superior temporal gyrus (MNI:x=-45,y=27,z=-15;t=5.164) and the bilateral middle cingulate gyrus (MNI:x=-6,y=-15,z=30;t=4.789),and the weaker PCC rs-FC (P＜0.05,AlphaSim-corrected for multiple comparisons,cluster size＞40) with the left postcentral gyrus(MNI:x=60,y=-12,z=45;t=-3.585) and the fight postcentral gyrus (MNI:x=-24,y=-33,z=66;t=-4.932).The rs-FC between the left orbital part of inferior frontal gyrus and the PCC was positively correlated with the PANSS negative symptom scores (r=0.487,P=-0.034).Conclusion It showed altered rs-FC of the PCC related network in first-episode adolescent schizophrenia patients.The increased rs-FC between the PCC and the orbitofrontal cortex may be associated with negative symptoms in adolescent schizophrenia patients.

Objective To explore the potential neural mechanism of adolescent schizophrenia by analysis of the resting state functional connectivity(rs-FC) network of posterior cingulate gyrus(PCC) with functional magnetic resonance imaging (fMRI).Methods Twenty-one first-episode medication-naive adolescent patients with schizophrenia were recruited from outpatients and inpatients in the Sichuan Mental Health Center from December 2016 to January 2018,and 21 gender-,age-and education-matched healthy ones were as control.The illness severity was estimated by PANSS and Psychotic Symptom Rating Scales (PSYRAT).All subjects was scanned by resting-state brain fMRI.The PCC was defined as a seed region of interest(ROI) after the imaging preprocessing,and the functional connectivity between seed region and other brain regions were calculated after the imaging data preprocessing.Statistical analysis of image data was processed by REST software.Results Data of 19 patients and 21 healthy volunteers were included in statistical analysis after realignment.Compared to the control group,the patients group exhibited increased PCC rs-FC (P＜0.05,AlphaSim-corrected for multiple comparisons,cluster size＞40) in two brain regions including the left orbital part of inferior frontal gyrus extended to the left superior temporal gyrus (MNI:x=-45,y=27,z=-15;t=5.164) and the bilateral middle cingulate gyrus (MNI:x=-6,y=-15,z=30;t=4.789),and the weaker PCC rs-FC (P＜0.05,AlphaSim-corrected for multiple comparisons,cluster size＞40) with the left postcentral gyrus(MNI:x=60,y=-12,z=45;t=-3.585) and the fight postcentral gyrus (MNI:x=-24,y=-33,z=66;t=-4.932).The rs-FC between the left orbital part of inferior frontal gyrus and the PCC was positively correlated with the PANSS negative symptom scores (r=0.487,P=-0.034).Conclusion It showed altered rs-FC of the PCC related network in first-episode adolescent schizophrenia patients.The increased rs-FC between the PCC and the orbitofrontal cortex may be associated with negative symptoms in adolescent schizophrenia patients.

ObjectiveTo investigate the association between tumor size and prognosis of patients with hepatocellular carcinoma (HCC) after hepatectomy.MethodsClinical data of 172 patients undergoing radical hepatectomy and diagnosed as HCC by pathological examination in the First Afifliated Hospital of Xi'an Jiaotong University between December 2002 and December 2011 were retrospectively studied. The informed consents of all patients were obtained and the local ethical committee approval had been received. Among the 172 patients, 139 were males and 33 were females; 98 were with age≤55 years old and 74 were with age >55 years old. The receiver operating characteristic (ROC) curve of the relationship between postoperative survival time and tumor size was drawn, and the cut-off value for tumor size was determined at 5.75 cm. According to the best cut-off value, the patients were divided into the small HCC group (tumor size < 5.75 cm,n=85) and huge HCC group (tumor size≥5.75 cm,n=87). The relationship between tumor size and clinicopathologic parameters was analyzed, and the median survival time, cumulative survival rate and disease free survival rate of two groups were compared. The clinicopathologic parameters were included as the factors inlfuencing the survival and prognosis of patients, and independent risk factor analysis was performed. The relationship between tumor size and clinicopathologic parameters was analyzed using Chi-square test. Kaplan-Meier method and Log-rank test were used for survival and prognosis analysis. Cox proportional hazard model was used for univariate analysis and multivariate analysis.ResultsTumor size was associated with the preoperative AFP, number of tumors and TNM staging (χ2=13.272, 9.378, 7.311;P<0.05). The median survival time and the median recurrence time for the huge HCC group were 24 months and 9 months respectively and were 39 months and 37 months for the small HCC group. The 1-, 3-, 5-year cumulative survival rate for the huge HCC group were 65.5%, 36.0%, 22.9% respectively and were 89.5%, 76.3%, 72.5% respectively for the small HCC group. The overall survival of the huge HCC group was lower than that of small HCC group (χ2=33.644,P<0.05). The 1-, 3-, 5-year disease free survival rate for the huge HCC group were 44.7%, 25.5%, 21.9% respectively and were 84.8%, 67.8%, 66.3% respectively for the small HCC group. The disease free survival rate of huge HCC group was lower than that of small HCC group (χ2=38.908,P<0.05). Preoperative platelets count (Plt)≥155×109/L, tumor size > 5.75 cm and advanced stage of TNM were the independent risk factors inlfuencing the postoperative prognosis of HCC patients (HR=1.588, 3.066, 2.029;P<0.05).ConclusionsTumor size is the independent risk factor inlfuencing the prognosis of HCC patients after hepatectomy. The prognosis of patients with tumor size > 5.75 cm is poor.

BACKGROUNDPancreatic cancer is a common malignant tumor of the digestive system. It is the fourth major cause of tumor-related death and its morbidity is increasing, and hence it is imperative to develop effective forms of therapy for pancreatic cancer. Peptide tyrosine-tyrosine (PYY) is an important gastrointestinal peptide hormone. According to previous literatures, PYY has been shown to inhibit tumor proliferation in cellular and animal models, but there has been limited research on the detailed mechanism of PYY in pancreatic cancer. This study was to observe the effects of PYY on pancreatic cancer cell and investigate the possible mechanism.

METHODSThe expression of Y1, Y2, and Y5 receptors on pancreatic cancer cell lines were detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The cytotoxicity of PYY toward the MiaPaCa-2 cell was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; the cell morphology and structure changes were observed under inverted microscope and transmission electron microscope respectively. Apoptosis and cell cycle were evaluated by flow cytometry. The activity of caspase-3 was determined by activity assay kits and Western blotting. The expression of survivin, vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) were determined by RT-qPCR and Western blotting.

RESULTSExpression of Y2 receptor is the most abundant PYY receptor on pancreatic cancer cell. PYY inhibited MiaPaCa-2 cell proliferation, blocked it in G0/G1 phase, increased the proportion of apoptosis cells and caspase-3 activity, and reduced the expression of survivin, VEGF, and COX-2.

CONCLUSIONSPYY weakened the ability of the pancreatic MiaPaCa-2 cell viability through cell cycle blocking and apoptosis inducing. The inhibition effect of PYY may be mediated by the Y2 receptor. The increased caspase-3 activity and reduced expression of survivin, VEGF, and COX-2 may serve as a novel mechanism in PYY inhibition effect on MiaPaCa-2 cell.

Blotting, Western ; Caspase 3 ; genetics ; metabolism ; Cell Cycle ; drug effects ; genetics ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclooxygenase 2 ; genetics ; metabolism ; Dipeptides ; pharmacology ; Humans ; Inhibitor of Apoptosis Proteins ; genetics ; metabolism ; Pancreatic Neoplasms ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

Background Pancreatic cancer is a common malignant tumor of the digestive system.It is the fourth major cause of tumor-related death and its morbidity is increasing,and hence it is imperative to develop effective forms of therapy for pancreatic cancer.Peptide tyrosine-tyrosine (PYY) is an important gastrointestinal peptide hormone.According to previous literatures,PYY has been shown to inhibit tumor proliferation in cellular and animal models,but there has been limited research on the detailed mechanism of PYY in pancreatic cancer.This study was to observe the effects of PYY on pancreatic cancer cell and investigate the possible mechanism.Methods The expression of Y1,Y2,and Y5 receptors on pancreatic cancer cell lines were detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR).The cytotoxicity of PYY toward the MiaPaCa-2 cell was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; the cell morphology and structure changes were observed under inverted microscope and transmission electron microscope respectively.Apoptosis and cell cycle were evaluated by flow cytometry.The activity of caspase-3 was determined by activity assay kits and Western blotting.The expression of survivin,vascular endothelial growth factor (VEGF),and cyclooxygenase-2 (COX-2) were determined by RT-qPCR and Western blotting.Results Expression of Y2 receptor is the most abundant PYY receptor on pancreatic cancer cell.PYY inhibited MiaPaCa-2 cell proliferation,blocked it in G0/G1 phase,increased the proportion of apoptosis cells and caspase-3 activity,and reduced the expression of survivin,VEGF,and COX-2.Conclusions PYY weakened the ability of the pancreatic MiaPaCa-2 cell viability through cell cycle blocking and apoptosis inducing.The inhibition effect of PYY may be mediated by the Y2 receptor.The increased caspase-3 activity and reduced expression of survivin,VEGF,and COX-2 may serve as a novel mechanism in PYY inhibition effect on MiaPaCa-2 cell.

Objective To determine the persistence time of genotype 4 hepatitis E (HE) viremia after the onset of clinical symptoms in HE patients and provide essential data for study on HE epidemiologieal transmission, so that to evaluate potential contagiousness of HE patients after clinical stage. Methods The first serum samples from 162 HE patients after hospitalized in Eastern China were collected and tested for hepatitis E virus (HEV) RNA by nested reversed transcription- polymerase chain reaction (RT-PCR). The persistence time of HEV viremia after the onset of clinical symptoms was estimated with Kaplan-Meier survival analysis. Results HEV RNA was detectable in 101 out of 162 serum samples with positive rate of 62.35%, which was all grouped to genotype 4 by homology analysis. Furthermore, HEV RNA was detectable in 74 (64.91%) out of 114 male and 27 (56.25%) out of 48 female, which was not significantly different (χ2 = 1.08, P=0. 30). Kaplan-Meier survival analysis showed that the median persistence time of HEV genotype 4 viremia was 24 days after the onset of clinical symptoms (95% CI: 18-30 days), which meant that the viremia of 50% HE patients remaining detectable up to 24 days after the onset. The 75% and 25% percentiles were 14 days and 31 days, respectively. There was no significant difference of viremia persistence time between male and female (Breslow test: P=0.98, Tarone-Ware test: P=0.91). Conclusions The viremia of 75% patients with HEV genotype 4 infection could persistent until 2 weeks after the onset of clinical symptoms and that of some patients could persistent over 1 month. It is indicated that the viremia is still persistent and HE patient could be a reservoir even after the clinical symptoms disappeared and biochemical marks normalized.