Intestinal CXCR6+ ILC3s migrate to the kidney and exacerbate renal fibrosis via IL-23 receptor signaling enhanced by PD-1 expression.

Group 3 innate lymphoid cells (ILC3s) regulate inflammation and tissue repair at mucosal sites, but whether these functions pertain to other tissues-like the kidneys-remains unclear. Here, we observed that renal fibrosis in humans was associated with increased ILC3s in the kidneys and blood. In mice, we showed that CXCR6+ ILC3s rapidly migrated from the intestinal mucosa and accumulated in the kidney via CXCL16 released from the injured tubules. Within the fibrotic kidney, ILC3s increased the expression of programmed cell death-1 (PD-1) and subsequent IL-17A production to directly activate myofibroblasts and fibrotic niche formation. ILC3 expression of PD-1 inhibited IL-23R endocytosis and consequently amplified the JAK2/STAT3/RORγt/IL-17A pathway that was essential for the pro-fibrogenic effect of ILC3s. Thus, we reveal a hitherto unrecognized migration pathway of ILC3s from the intestine to the kidney and the PD-1-dependent function of ILC3s in promoting renal fibrosis.

Washed microbiota transplantation improves renal function in patients with renal dysfunction: a retrospective cohort study.

BACKGROUND: Changes in the gut microbiota composition is a hallmark of chronic kidney disease (CKD), and interventions targeting the gut microbiota present a potent approach for CKD treatment. This study aimed to evaluate the efficacy and safety of washed microbiota transplantation (WMT), a modified faecal microbiota transplantation method, on the renal activity of patients with renal dysfunction. METHODS: A comparative analysis of gut microbiota profiles was conducted in patients with renal dysfunction and healthy controls. Furthermore, the efficacy of WMT on renal parameters in patients with renal dysfunction was evaluated, and the changes in gut microbiota and urinary metabolites after WMT treatment were analysed. RESULTS: Principal coordinate analysis revealed a significant difference in microbial community structure between patients with renal dysfunction and healthy controls (P = 0.01). Patients with renal dysfunction who underwent WMT exhibited significant improvement in serum creatinine, estimated glomerular filtration rate, and blood urea nitrogen (all P < 0.05) compared with those who did not undergo WMT. The incidence of adverse events associated with WMT treatment was low (2.91%). After WMT, the Shannon index of gut microbiota and the abundance of several probiotic bacteria significantly increased in patients with renal dysfunction, aligning their gut microbiome profiles more closely with those of healthy donors (all P < 0.05). Additionally, the urine of patients after WMT demonstrated relatively higher levels of three toxic metabolites, namely hippuric acid, cinnamoylglycine, and indole (all P < 0.05). CONCLUSIONS: WMT is a safe and effective method for improving renal function in patients with renal dysfunction by modulating the gut microbiota and promoting toxic metabolite excretion.

Washed microbiota transplantation improves haemoglobin levels in anaemia of chronic disease.

BACKGROUND: Anaemia of chronic disease (ACD) is the second most common type of anaemia and lacks an effective treatment. Patients with anaemia are reported to have altered gut microbial profiles, which may affect erythropoiesis. Here, we investigated the gut microbial features of patients with ACD and determined whether regulating gut microbiota using washed microbiota transplantation (WMT) was effective in treating ACD. METHODS: We compared the gut microbiota profile of patients with ACD and healthy controls, evaluated the efficacy of WMT on haematological parameters in the patients, and analysed the alterations in gut microbiota after WMT treatment. RESULTS: Patients with ACD had lower gut microbial richness, and differences in microbial composition and function, relative to healthy controls. Additionally, the relative abundances of two butyrate-producing genera Lachnospiraceae NK4A136 group and Butyricicoccus, were positively correlated with the haemoglobin (HGB) level and lower in patients with ACD than controls. WMT significantly increased HGB levels in patients with ACD. After the first, second and third WMT rounds, normal HGB levels were restored in 27.02%, 27.78% and 36.37% (all p < .05) of patients with ACD, respectively. Moreover, WMT significantly increased the abundance of butyrate-producing genera and downregulated gut microbial functions that were upregulated in patients with ACD. CONCLUSIONS: Patients with ACD exhibited differences in gut microbial composition and function relative to healthy controls. WMT is an effective treatment for ACD that reshapes gut microbial composition, restores butyrate-producing bacteria and regulates the functions of gut microbiota.

Anemia Is Associated with Disease Severity, Hepatic Complications, and Progression of Wilson Disease: A Retrospective Cohort Study.

INTRODUCTION: Anemia is a common manifestation of chronic liver diseases. It is a predictor of severe disease, a high risk of complications, and poor outcomes in various liver diseases. However, it remains unclear whether anemia serves as a similar indicator in patients with Wilson disease (WD). Therefore, this study aimed to investigate the relationship between anemia and severity, hepatic complications, and the progression of WD. METHODS: Medical data were collected retrospectively from January 1, 2016, to December 31, 2020. Univariate and multivariate analyses were carried out to investigate the relationship between anemia and liver-associated disease severity, hepatic complications, and the progression of WD. RESULTS: A total of 288 WD patients (48 with and 240 without anemia) were enrolled in the study. Multivariate linear regression revealed that WD patients with anemia had significantly higher levels of bilirubin, alanine transaminase, prothrombin time, international normalized ratio, type Ⅳ collagen, and hyaluronic acid and significantly lower levels of albumin, total cholesterol, and high-density lipoprotein-cholesterol (all p < 0.05). Multivariate logistic regression showed that anemia was a risk factor for gastric varices and ascites (all p < 0.05). Fully adjusted Cox regression revealed that anemia was an independent risk factor for advanced Child-Pugh classification (p = 0.034). CONCLUSIONS: Anemia was common in WD patients and was associated with greater disease severity, a higher risk of hepatic complications, and a faster progression.

The Gut-Liver Axis in Nonalcoholic Fatty Liver Disease: Association of Intestinal Permeability with Disease Severity and Treatment Outcomes.

Objective: To investigate the association between intestinal permeability and severity of nonalcoholic fatty liver disease (NAFLD) and the value of intestinal permeability in predicting the efficacy of metabolic therapy for NAFLD. Methods: Disease severity was compared between patients with normal and elevated intestinal permeability; correlations between D-lactate and different NAFLD parameters were analyzed; and the effects of metabolic therapy on NAFLD patients with normal and elevated intestinal permeability were evaluated. Results: A total of 190 patients with NAFLD were enrolled. NAFLD patients with elevated intestinal permeability had significantly higher levels of liver test parameters, liver ultrasonographic fat attenuation parameter, triglyceride, homeostasis model assessment of insulin resistance value, and diamine oxidase (all P˂0.05) than NAFLD patients with normal intestinal permeability. Furthermore, serum D-lactate levels were positively correlated with alanine transaminase, aspartate transaminase, gamma-glutamyl transpeptidase, total bilirubin, indirect bilirubin, fat attenuation parameter, triglyceride, and diamine oxidase (all P ˂ 0.05). Moreover, NAFLD patients with elevated intestinal permeability showed less improvement in TG levels (P = 0.014) after metabolic therapy. Conclusion: Intestinal permeability correlates with the disease severity in patients with NAFLD. Moreover, intestinal permeability may have value for predicting the efficacy of metabolic therapy for NAFLD patients.

[Emerging pathogenic role of group 3 innate lymphoid cells in inflammatory diseases].

Group 3 innate lymphoid cells (ILC3) as a family member of innate lymphoid cells (ILCs), have been defined as novel innate immune cells in the past decade. ILC3 include a variety of heterogenous subsets with different phenotypes and functions, which are mainly distributed in barrier organs such as the intestine, lung and skin. They play an important role in immune regulation, tissue repair and lymphoid tissue formation. However, in various inflammatory diseases, ILC3 become dysregulated and participate in the pathogenesis through secreting a series of cytokines such as interleukin (IL)-17, IL-22, interferon-γ (IFN-γ) and granulocyte-macrophage colony-stimulating factor (GM-CSF) to modulate other immune cells and induce the formation of ectopic lymphoid structures. Therefore, it is of great significance to explore the phenotype and function of ILC3 in order to advance the understanding of inflammatory diseases and find new therapeutic targets. In this article, the phenotypic characteristics, biological functions and research progress of ILC3 in inflammatory diseases were reviewed.

Association Between Ascites and Clinical Findings in Patients with Acute Pancreatitis: A Retrospective Study.

BACKGROUND Complications are the most important outcome determinants for acute pancreatitis (AP). We designed this single-center retrospective study to evaluate the clinical findings (complications, disease severity, and outcomes) of 218 patients with AP and to identify variables associated with ascites. MATERIAL AND METHODS We extracted clinical data from consecutive patients with AP and divided them into 2 groups based on presence or absence of ascites. We compared disease severity, complications, and outcomes between groups. RESULTS We analyzed data from 218 patients with AP (43 with ascites and 175 without it). The patients with ascites had a more severe disease (higher incidence of pancreatic inflammation [90.70% vs 68.57%; P=0.003], higher modified computed tomography severity index score [2.00 (0.00-2.00) vs 4.00 (4.00-6.00); P<0.001], higher incidence of moderate/severe AP [53.49% vs 13.14%; P<0.001]) and poorer outcomes (higher incidence of ventilation [6.98% vs 0.57%; P=0.025] and vasopressor use [4.65% vs 0%; P=0.038], and longer hospital stays [10.00 (7.00-13.00) vs 8.00 (5.00-10.00); P=0.007]) than those without ascites. Moreover, patients with ascites also displayed a higher risk for pancreatic fluid collection (odds ratio [OR]=9.206; 95% confidence interval [CI], 2.613-32.447; P<0.001), renal failure (OR=5.732; 95% CI, 1.025-32.041; P=0.024), respiratory failure (OR=6.242; 95% CI, 1.034-37.654; P=0.029), and pleural effusion (OR=5.186; 95% CI, 1.381-19.483; P<0.001) than those without ascites. CONCLUSIONS The findings from the experience of a single center of patients with AP showed that pancreatic fluid collections, renal failure, respiratory failure, and pleural effusion were associated with the development of ascites.

Pleural Effusion Is Associated with Severe Renal Dysfunction in Patients with Acute Pancreatitis.

BACKGROUND Renal dysfunction is a leading cause of death in patients with acute pancreatitis (AP) and often occurs later than respiratory complications. Whether respiratory complications can predict renal impairment remains unclear. The aim of this study was to investigate the association between pleural effusion and renal dysfunction in AP. MATERIAL AND METHODS Medical records were reviewed from individuals who were hospitalized with AP from January 1, 2015 to December 31, 2019. The patients were divided into 2 groups, based on the presence or absence of pleural effusion on admission. Disease severity, renal function parameters, and outcomes were compared between the 2 groups. RESULTS A total of 222 patients were enrolled, 25 of whom had pleural effusion on admission and 197 who did not. Patients with AP who had pleural effusion had more serious illness (higher incidences of pancreatic inflammation, pancreatic fluid collection, and moderate-to-severe AP; worse Bedside Index for Severity in Acute Pancreatitis score; and a higher modified computed tomography severity index [all P<0.05]) plus worse outcomes (higher incidences of ventilation and vasopressor use [both P<0.05]). Moreover, patients with pleural effusion had a higher level of blood urea nitrogen and lower estimated glomerular filtration rate (both P<0.05). After adjustment for potential confounders, pleural effusion was a risk factor for renal failure in patients with AP (odds ratio 6.32, 95% confidence interval 1.08-36.78, P=0.040). CONCLUSIONS Pleural effusion is associated with severe renal dysfunction in AP. Therefore, efforts should be made to improve early recognition and timely treatment of renal failure by closely monitoring renal function in patients with AP and pleural effusion on admission.

Association between periodontitis and systemic lupus erythematosus: a meta-analysis.

OBJECTIVE: The objective of this study was to explore the association between periodontitis and systemic lupus erythematosus (SLE). METHODS: To identify eligible studies, the PubMed, EMBASE and Web of Science databases were searched from inception to 19 September 2019. Associations of periodontitis, and other periodontal parameters, with SLE were assessed. RESULTS: Ten studies involving 80,633 subjects were included in this meta-analysis. Pooled data showed a significant association between periodontitis and SLE (odds ratio=5.32, 95% confidence interval (CI) 1.69-16.78, p = 0.004). In addition, SLE patients had a higher prevalence of bleeding on probing (mean difference = 0.03, 95% CI 0.00-0.06, p = 0.02) and higher mean clinical attachment loss (mean difference = 0.69, 95% CI 0.39-1.00, p < 0.001). However, there were no significant differences between SLE and reference subjects in mean plaque index, gingival index, pocket depth or decayed, missing or filled teeth. CONCLUSIONS: This study demonstrates a significant association between periodontitis and SLE, which indicates that avoidance of periodontitis by maintaining oral health may be a simple and economical way to prevent SLE.

Cirrhosis in Wilson Disease is characterized by Impaired Hepatic Synthesis, Leukopenia and Thrombocytopenia.

Background: Patients with Wilson disease (WD) progress to cirrhosis at an early age but have good prognoses. This study aimed to delineate hepatic features in WD patients with or without cirrhosis. Methods: Medical data were retrospectively collected from 27 July 2015 to 27 June 2018. WD patients were divided into two groups based on whether or not they progressed to cirrhosis. Liver function, portal hypertension features and hematocytopenia rates were compared between groups. Results: The study enrolled 119 WD patients with cirrhosis and 53 WD patients without cirrhosis. There were no differences between groups for liver enzyme levels or incidence rates of Kayser-Fleischer ring (all P > 0.05). Ascites and hepatic encephalopathy were nearly absent in both groups, and almost all patients were Child-Pugh group A. However, WD-associated cirrhotic patients had a higher prothrombin time (beta = 0.908, P = 0.004) and international normalized ratio (beta = 0.089, P = 0.040), wider portal vein diameter (beta = 1.330, P < 0.001), and an increased risk of splenomegaly/splenectomy (odds ratio [OR] = 4.36, 95% confidence interval [CI]: 2.15-8.84, P < 0.001). Moreover, WD-associated cirrhotic patients have significantly increased risks of leukopenia (OR = 2.30, 95% CI: 1.00-5.25, P = 0.049) and thrombocytopenia (OR = 6.89, 95% CI: 2.01-23.59, P = 0.002). Conclusions: Despite presenting good outcomes, mild hepatocyte injury, and good hepatic metabolic function, WD-associated cirrhotic patients show more serious impairment of hepatic synthetic function, wider portal vein diameter, and higher risk of splenomegaly due to portal hypertension.

Use of gastric-acid suppressants may be a risk factor for enteric peritonitis in patients undergoing peritoneal dialysis: A meta-analysis.

WHAT IS KNOWN AND OBJECTIVE: Mounting evidence suggests that long-term use of gastric-acid suppressants (GASs) may be associated with adverse effects. Whether GAS use increases the risk of enteric peritonitis in patients undergoing peritoneal dialysis (PD) is not known. The aim of this meta-analysis was to evaluate the association between GAS use and enteric peritonitis in PD patients. METHODS: We searched PubMed, Embase and Cochrane Library databases from inception to 23 January 2018 to identify eligible studies. The primary outcome was an association between GAS use and enteric peritonitis in PD patients. RESULTS AND DISCUSSION: Six studies involving 829 people were included in this meta-analysis. Pooled data showed that GAS use in PD patients was associated with an increased risk of enteric peritonitis (odds ratio [OR] = 1.27; 95% confidence interval [CI]: 1.02-1.57, I2  = 48%). Subgroup analyses based on GAS type revealed that histamine-2 receptor antagonists (H2 RAs) might increase the risk of enteric peritonitis in PD patients (OR = 1.40; 95% CI: 1.01-1.93; I2  = 8%), but proton pump inhibitors (PPIs) might not (1.13; 0.72-1.77; 6; 34%). WHAT IS NEW AND CONCLUSION: Gastric-acid suppressants use might be a risk factor for enteric peritonitis in PD patients. In particular, H2 RAs increased the risk of enteric peritonitis, but PPIs did not. Therefore, to prevent enteric peritonitis, H2 RAs should probably be prescribed with caution for PD patients.

Clusters of Human Infections With Avian Influenza A(H7N9) Virus in China, March 2013 to June 2015.

Multiple clusters of human infections with novel avian influenza A(H7N9) virus have occurred since the virus was first identified in spring 2013. However, in many situations it is unclear whether these clusters result from person-to-person transmission or exposure to a common infectious source. We analyzed the possibility of person-to-person transmission in each cluster and developed a framework to assess the likelihood that person-to-person transmission had occurred. We described 21 clusters with 22 infected contact cases that were identified by the Chinese Center for Disease Control and Prevention from March 2013 through June 2015. Based on detailed epidemiological information and the timing of the contact case patients' exposures to infected persons and to poultry during their potential incubation period, we graded the likelihood of person-to-person transmission as probable, possible, or unlikely. We found that person-to-person transmission probably occurred 12 times and possibly occurred 4 times; it was unlikely in 6 clusters. Probable nosocomial transmission is likely to have occurred in 2 clusters. Limited person-to-person transmission is likely to have occurred on multiple occasions since the H7N9 virus was first identified. However, these transmission events represented a small fraction of all identified cases of H7N9 human infection, and sustained person-to-person transmission was not documented.

Early rigorous control interventions can largely reduce dengue outbreak magnitude: experience from Chaozhou, China.

BACKGROUND: Dengue fever is a severe public heath challenge in south China. A dengue outbreak was reported in Chaozhou city, China in 2015. Intensified interventions were implemented by the government to control the epidemic. However, it is still unknown the degree to which intensified control measures reduced the size of the epidemics, and when should such measures be initiated to reduce the risk of large dengue outbreaks developing? METHODS: We selected Xiangqiao district as study setting because the majority of the indigenous cases (90.6%) in Chaozhou city were from this district. The numbers of daily indigenous dengue cases in 2015 were collected through the national infectious diseases and vectors surveillance system, and daily Breteau Index (BI) data were reported by local public health department. We used a compartmental dynamic SEIR (Susceptible, Exposed, Infected and Removed) model to assess the effectiveness of control interventions, and evaluate the control effect of intervention timing on dengue epidemic. RESULTS: A total of 1250 indigenous dengue cases was reported from Xiangqiao district. The results of SEIR modeling using BI as an indicator of actual control interventions showed a total of 1255 dengue cases, which is close to the reported number (n = 1250). The size and duration of the outbreak were highly sensitive to the intensity and timing of interventions. The more rigorous and earlier the control interventions implemented, the more effective it yielded. Even if the interventions were initiated several weeks after the onset of the dengue outbreak, the interventions were shown to greatly impact the prevalence and duration of dengue outbreak. CONCLUSIONS: This study suggests that early implementation of rigorous dengue interventions can effectively reduce the epidemic size and shorten the epidemic duration.

Contact Tracing for Imported Case of Middle East Respiratory Syndrome, China, 2015.

Confirmation of an imported case of infection with Middle East respiratory syndrome coronavirus in China triggered intensive contact tracing and mandatory monitoring. Using a hotline and surveillance video footage was effective for tracing all 110 identified contacts. Contact monitoring detected no secondary transmission of infection in China.

Effect of Live Poultry Market Interventions on Influenza A(H7N9) Virus, Guangdong, China.

Since March 2013, three waves of human infection with avian influenza A(H7N9) virus have been detected in China. To investigate virus transmission within and across epidemic waves, we used surveillance data and whole-genome analysis of viruses sampled in Guangdong during 2013-2015. We observed a geographic shift of human A(H7N9) infections from the second to the third waves. Live poultry market interventions were undertaken in epicenter cities; however, spatial phylogenetic analysis indicated that the third-wave outbreaks in central Guangdong most likely resulted from local virus persistence rather than introduction from elsewhere. Although the number of clinical cases in humans declined by 35% from the second to the third waves, the genetic diversity of third-wave viruses in Guangdong increased. Our results highlight the epidemic risk to a region reporting comparatively few A(H7N9) cases. Moreover, our results suggest that live-poultry market interventions cannot completely halt A(H7N9) virus persistence and dissemination.

Family clusters of avian influenza A H7N9 virus infection in Guangdong Province, China.

Since its first identification, the epizootic avian influenza A H7N9 virus has continued to cause infections in China. Two waves were observed during this outbreak. No cases were reported from Guangdong Province during the first wave, but this province became one of the prime outbreak sites during the second wave. In order to identify the transmission potential of this continuously evolving infectious virus, our research group monitored all clusters of H7N9 infections during the second wave of the epidemic in Guangdong Province. Epidemiological, clinical, and virological data on these patients were collected and analyzed. Three family clusters including six cases of H7N9 infection were recorded. The virus caused severe disease in two adult patients but only mild symptoms for all four pediatric patients. All patients reported direct poultry or poultry market exposure history. Relevant environment samples collected according to their reported exposures tested H7N9 positive. Virus isolates from patients in the same cluster shared high sequence similarities. In conclusion, although continually evolving, the currently circulating H7N9 viruses in Guangdong Province have not yet demonstrated the capacity for efficient and sustained person-to-person transmission.

Continuing reassortment leads to the genetic diversity of influenza virus H7N9 in Guangdong, China.

UNLABELLED: On 30 March 2013, a novel avian influenza A H7N9 virus causing severe human respiratory infections was identified in China. Preliminary sequence analyses have shown that the virus is a reassortant of H7N9 and H9N2 avian influenza viruses. In this study, we conducted enhanced surveillance for H7N9 virus in Guangdong, China, from April to August 2013. We isolated two H7N9 viral strains from environmental samples associated with poultry markets and one from a clinical patient. Sequence analyses showed that the Guangdong H7N9 virus isolated from April to May shared high sequence similarity with other strains from eastern China. The A/Guangdong/1/2013 (H7N9) virus isolated from the Guangdong patient on 10 August 2013 was divergent from previously sequenced H7N9 viruses and more closely related to local circulating H9N2 viruses in the NS and NP genes. Phylogenetic analyses revealed that four internal genes of the A/Guangdong/1/2013 (H7N9) virus-the NS, NP, PB1, and PB2 genes-were in clusters different from those for H7N9 viruses identified previously in other provinces of China. The discovery presented here suggests that continuing reassortment led to the emergence of the A/Guangdong/1/2013 (H7N9) virus as a novel H7N9 virus in Guangdong, China, and that viral adaptation to avian and human hosts must be assessed. IMPORTANCE: In this study, we isolated and characterized the avian influenza A H7N9 virus in Guangdong, China, from April to August 2013. We show that the viruses isolated from Guangdong environmental samples and chickens from April to May 2013 were highly similar to other H7N9 strains found in eastern China. The H7N9 virus isolated from the clinical patient in Guangdong in August 2013 was divergent from previously identified H7N9 viruses, with the NS and NP genes originating from recent H9N2 viruses circulating in the province. This study provides direct evidence that continuing reassortment occurred and led to the emergence of a novel H7N9 influenza virus in Guangdong, China. These results also shed light on how the H7N9 virus evolved, which is critically important for future monitoring and tracing of viral transmission.

Circulation of reassortant influenza A(H7N9) viruses in poultry and humans, Guangdong Province, China, 2013.

Influenza A(H7N9) virus emerged in eastern China in February 2013 and continues to circulate in this region, but its ecology is poorly understood. In April 2013, the Guangdong Provincial Center for Disease Control and Prevention (CDC) implemented environmental and human syndromic surveillance for the virus. Environmental samples from poultry markets in 21 city CDCs (n=8,942) and respiratory samples from persons with influenza-like illness or pneumonia (n=32,342) were tested; viruses isolated from 6 environmental samples and 16 patients were sequenced. Sequence analysis showed co-circulation of 4 influenza A(H7N9) virus strains that evolved by reassortment with avian influenza A(H9N2) viruses circulating in this region. In addition, an increase in human cases starting in late 2013 coincided with an increase in influenza A H7 virus isolates detected by environmental surveillance. Co-circulation of multiple avian influenza viruses that can infect humans highlights the need for increased surveillance of poultry and potential environmental sources.

Poultry market closures and human infection with influenza A(H7N9) virus, China, 2013-14.

Closure of live poultry markets was implemented in areas affected by the influenza virus A(H7N9) outbreak in China during winter, 2013-14. Our analysis showed that closing live poultry markets in the most affected cities of Guangdong and Zhejiang provinces was highly effective in reducing the risk for H7N9 infection in humans.

Serologic screenings for H7N9 from three sources among high-risk groups in the early stage of H7N9 circulation in Guangdong Province, China.

BACKGROUND: The aim of this study was to assess the prevalence of the novel avian influenza A virus (H7N9) in three high risk groups. The groups were divided into those exposed through infected individuals, those exposed through poultry and those individuals exposed through the external environment, in the early stage of the epidemic in Guangdong Province, which is located in the southern region of China. METHODS: Serologic studies were conducted among samples collected from individuals who had close contact with the first H7N9 infected patient reported in Guangdong Province, those who were most likely exposed to the first group of H7N9 infected poultry, and those who might have been exposed to H7N9 in the environmental settings, namely hemagglutinin inhibition (HI) and microneutralizaiton(MN) assays using three viruses as antigens. RESULTS: The alignment results of the viral sequences indicated the similarity of the HA gene sequence among viruses from exposure to infected poultry, infected humans and contaminated environments were highly conserved. Seven samples of individuals exposed to contaminated environments were positive in the HI assay and one sample among them was positive in the MN assay using poultry H7N9 virus as the antigen. One sample was positive against human H7N9 virus and 3 samples were positive against environmental H7N9 among those that were in contact with infected patients in HI assay. None of these were positive in MN assay. All HI titers of the 240 samples from those individuals in contact with infected poultry were less than 40 aganist the antigens from three viruses. CONCLUSIONS: The results suggest that when the H7N9 virus was in the early stages of circulation in Guangdong Province, the antigenic sites of the HA proteins of the H7N9 strain isolated from different hosts were highly conserved. The risk of new infection is low in individuals who have contact with the infected patients, poultry or a contaminated environment in the early stages of the circulation of the H7N9 virus.