title: Enzyme-linked immunospot assay response to recombinant CFP-10/ESAT-6 fusion protein among patients with spinal tuberculosis: implications for diagnosis and monitoring of surgical therapy.
abstract: OBJECTIVE
  This study aimed to assess the performance of a laboratory-developed recombinant CFP-10/ESAT-6 fusion protein (rCFP-10/ESAT-6)-based enzyme-linked immunospot (ELISPOT) assay for the diagnosis of spinal tuberculosis (TB) in China, and to evaluate the value of the ELISPOT assay for monitoring the efficacy of surgical treatment.
  
  
  METHODS
  In the first part of the study, a total of 78 participants were consecutively recruited for ELISPOT using rCFP-10/ESAT-6 as a stimulus. The cutoff value for ELISPOT positivity was based on the results of receiver operating characteristic curve analysis. In the second part, this approach was evaluated in a prospective study including 102 patients with suspected spinal TB. Data on clinical characteristics of the patients and conventional laboratory results were collected, and blood samples were obtained for ELISPOT using rCFP-10/ESAT-6 as a stimulus.
  
  
  RESULTS
  Among the 102 patients with suspected spinal TB, 11 were excluded from the study. Twenty-three patients (25.2%) had culture-confirmed TB and 29 (31.9%) patients had probable TB. Among the spinal TB patients, the ELISPOT had a sensitivity of 82.7%, compared to a sensitivity of 61.5% for the purified protein derivative (PPD) skin test. The specificity was 87.2% for ELISPOT and 46.2% for the PPD skin test among 39 subjects with non-TB disease. The number of spot-forming cells and/or the positive rate of the ELISPOT assay were associated with aging, emaciation, and paravertebral abscess. The number of subjects with responses to rCFP-10/ESAT-6 slightly decreased after surgical treatment in spinal TB patients.
  
  
  CONCLUSIONS
  A laboratory-developed rCFP-10/ESAT-6 ELISPOT assay is a useful adjunct to current tests for the diagnosis of spinal TB.
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, 510515, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Yuan
authors.forename: Xueqiong
authors.initials: X
authors.lastname: Wu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Zhaoming
authors.initials: Z
authors.lastname: Zhong
authors.forename: Jianting
authors.initials: J
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D058501:Enzyme-Linked Immunospot Assay / Q000379:methods / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011993:Recombinant Fusion Proteins / Q000276:immunology*; D012016:Reference Values; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014374:Tuberculin Test; D014399:Tuberculosis, Spinal / Q000175:diagnosis* / Q000276:immunology* / Q000601:surgery; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C525005:ESAT-6 antigen, Mycobacterium leprae; D011993:Recombinant Fusion Proteins
keywords: Diagnosis; ELISPOT assay; Recombinant CFP-10/ESAT-6 fusion protein; Spinal tuberculosis; Surgical therapy