Selected RD1 Peptides for Active Tuberculosis Diagnosis: Comparison of a Gamma Interferon Whole-Blood Enzyme-Linked Immunosorbent Assay and an Enzyme-Linked Immunospot Assay

Clin Diagn Lab Immunol. 2005 Nov;12(11):1311-6. doi: 10.1128/CDLI.12.11.1311-1316.2005.

Abstract

We recently set up a gamma interferon (IFN-gamma) enzyme-linked immunospot assay (ELISPOT), using selected early secreted antigenic target 6 (ESAT-6) peptides, that appears specific for active tuberculosis (A-TB). However, ELISPOT is difficult to automate. Thus, the objective of this study was to determine if the same selected peptides may be used in a technique more suitable for routine work in clinical laboratories, such as whole-blood enzyme-linked immunosorbent assay (WBE). For this purpose, 27 patients with A-TB and 41 control patients were enrolled. Our WBE, using the already described selected peptides from ESAT-6 plus three new ones from culture filtrate protein 10, was performed, and data were compared with those obtained by ELISPOT. Using our selected peptides, IFN-gamma production, evaluated by both WBE and ELISPOT, was significantly higher in patients with A-TB than in controls (P < 0.0001). Statistical analysis showed a good correlation between the results obtained by WBE and ELISPOT (r = 0.80, P < 0.001). To substantiate our data, we compared our WBE results with those obtained by QuantiFERON-TB Gold, a whole-blood assay based on region of difference 1 (RD1) overlapping peptides approved for TB infection diagnosis. We observed a slightly higher sensitivity with QuantiFERON-TB Gold than with our WBE (89% versus 81%); however, our test provided a better specificity result (90% versus 68%). In conclusion, results obtained by WBE based on selected RD1 peptides significantly correlate with those generated by ELISPOT. Moreover, our assay appears more specific for A-TB diagnosis than QuantiFERON-TB Gold, and thus it may represent a complementary tool for A-TB diagnosis for routine use in clinical laboratories.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Bacterial / blood
  • Bacterial Proteins
  • Enzyme-Linked Immunosorbent Assay / methods
  • Humans
  • Interferon-gamma / blood*
  • Peptide Fragments* / blood
  • Recombinant Fusion Proteins / blood
  • Tuberculosis, Pulmonary / blood
  • Tuberculosis, Pulmonary / diagnosis*
  • Tuberculosis, Pulmonary / immunology

Substances

  • Antigens, Bacterial
  • Bacterial Proteins
  • ESAT-6 protein, Mycobacterium tuberculosis
  • ESAT-6-CFP10 fusion protein
  • Peptide Fragments
  • Recombinant Fusion Proteins
  • Interferon-gamma