title: Evaluation of a semi-quantitative ELISA for IgA antibody against Epstein-Barr virus capsid antigen in the serological diagnosis of nasopharyngeal carcinoma.
abstract: OBJECTIVE
  This study was designed to establish an ELISA method, as well as the cut-off value, for IgA against Epstein-Barr virus (EBV) viral capsid antigen (VCA), as a screening assay for nasopharyngeal carcinoma (NPC) in southern China. In addition, the correlation between relative optical density (rOD) values from ELISA and titers from the immunoenzymatic assay (IEA) was also evaluated.
  
  
  METHODS
  Two hundred and fifty-eight NPC cases, 33 non-NPC head and neck cancer patients, and 1156 healthy controls were recruited for this study. VCA-IgA and early antigen (EA)-IgA were measured by ELISA kits and IEA in parallel.
  
  
  RESULTS
  The total precision of the VCA-IgA ELISA achieved a level of <13.0% coefficient of variation. An rOD value of 1.60 for the VCA-IgA ELISA was determined as the cut-off point for southern China, and the sensitivity and specificity for NPC diagnosis when using this cut-off value were 93.0% and 92.4%, respectively. The area under the receiver operating characteristic curve (ROC-AUC) value was 0.969. The correlation coefficient between titers and rOD values was 0.957. rOD values were correlated with NPC overall stage and lymph node involvement.
  
  
  CONCLUSIONS
  The cut-off level established in our study could be used to facilitate more accurate diagnosis of NPC in southern China. The rOD value might be an index for NPC prognosis, since it shows a good correlation with the titer from IEA.
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, PR China.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, PR China.
authors.forename: Peidong
authors.initials: P
authors.lastname: Chi
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, PR China.
authors.forename: Weida
authors.initials: W
authors.lastname: Wang
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, PR China.
authors.forename: Linfang
authors.initials: L
authors.lastname: Li
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, PR China.
authors.forename: Yaoling
authors.initials: Y
authors.lastname: Luo
authors.affiliation: EUROIMMUN Medical Diagnostics (China) Co., Ltd, Beijing, PR China.
authors.forename: Jihuan
authors.initials: J
authors.lastname: Fu
authors.affiliation: EUROIMMUN Medical Diagnostics (China) Co., Ltd, Beijing, PR China.
authors.forename: Liuyan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, PR China. Electronic address: liuwl@sysucc.org.cn.
authors.forename: Wanli
authors.initials: W
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology*; D000956:Antigens, Viral / Q000276:immunology*; D036022:Capsid Proteins / Q000276:immunology*; D002277:Carcinoma; D004797:Enzyme-Linked Immunosorbent Assay; D020031:Epstein-Barr Virus Infections / Q000150:complications*; D005260:Female; D004854:Herpesvirus 4, Human / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis* / Q000209:etiology*; D009367:Neoplasm Staging; D012372:ROC Curve; D011933:Reagent Kits, Diagnostic; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D036022:Capsid Proteins; C041788:Epstein-Barr viral capsid antigen; D007070:Immunoglobulin A; D011933:Reagent Kits, Diagnostic
keywords: ELISA; Early antigen; Epstein–Barr virus; Immunoenzymatic assay; Nasopharyngeal carcinoma; Viral capsid antigen