Kimuda Simon G, Andia-Biraro Irene, Egesa Moses, Bagaya Bernard S, Raynes John G, Levin Jonathan, Elliott Alison M, Cose Stephen
Department of Medical Microbiology, School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda.
MRC/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.
PLoS One. 2017 Nov 21;12(11):e0188396. doi: 10.1371/journal.pone.0188396. eCollection 2017.
QuantiFERON®-TB Gold in-tube (QFT-GIT) supernatants may be important samples for use in assessment of anti-tuberculosis (TB) antibodies when only limited volumes of blood can be collected and when a combination of antibody and cytokine measurements are required. These analytes, when used together, may also have the potential to differentiate active pulmonary TB (APTB) from latent TB infection (LTBI). However, few studies have explored the use of QFT-GIT supernatants for investigations of antibody responses. This study determined the correlation and agreement between anti-CFP-10 and anti-ESAT-6 antibody concentrations in QFT-GIT nil supernatant and serum pairs from 68 TB household contacts. We also explored the ability of Mycobacterium tuberculosis (M.tb) specific antibodies, or ratios of antibody to interferon gamma (IFN-γ) in QFT-GIT supernatants, to differentiate 97 APTB cases from 58 individuals with LTBI. Sputum smear microscopy was used to define APTB, whereas the QFT-GIT and tuberculin skin test were used to define LTBI. There were strong and statistically significant correlations between anti-CFP-10 and anti-ESAT-6 antibodies in unstimulated QFT-GIT supernatants and sera (r = 0.89; p<0.0001 for both), and no significant differences in antibody concentration between them. Anti-CFP-10 & anti-ESAT-6 antibodies differentiated APTB from LTBI with sensitivities of 88.7% & 71.1% and specificities of 41.4% & 51.7% respectively. Anti-CFP-10 antibody/M.tb specific IFN-γ and anti-ESAT-6 antibody/M.tb specific IFN-γ ratios had sensitivities of 48.5% & 54.6% and specificities of 89.7% and 75.9% respectively. We conclude that QFT-GIT nil supernatants may be used in the place of sera when measuring antibody responses, reducing blood volumes needed for such investigations. Antibodies in QFT-GIT nil supernatants on their own discriminate APTB from LTBI with high sensitivity but have poor specificity, whereas the reverse is true when antibodies are used in combination with M.tb specific cytokines. Further antibody and antibody/cytokine combinations need to be explored to achieve better diagnostic accuracy.
当只能采集有限体积的血液，且需要同时检测抗体和细胞因子时，全血γ干扰素释放试验（QFT-GIT）的上清液可能是用于评估抗结核（TB）抗体的重要样本。这些分析物一起使用时，也有可能区分活动性肺结核（APTB）和潜伏性结核感染（LTBI）。然而，很少有研究探索使用QFT-GIT上清液来研究抗体反应。本研究确定了68例结核病家庭接触者的QFT-GIT无刺激上清液和血清中抗CFP-10和抗ESAT-6抗体浓度之间的相关性和一致性。我们还探讨了结核分枝杆菌（M.tb）特异性抗体，或QFT-GIT上清液中抗体与干扰素γ（IFN-γ）的比值，区分97例APTB病例和58例LTBI个体的能力。痰涂片显微镜检查用于定义APTB，而QFT-GIT和结核菌素皮肤试验用于定义LTBI。未刺激的QFT-GIT上清液和血清中抗CFP-10和抗ESAT-6抗体之间存在强且具有统计学意义的相关性（r = 0.89；两者p<0.0001），且它们之间的抗体浓度无显著差异。抗CFP-10和抗ESAT-6抗体区分APTB和LTBI的敏感性分别为88.7%和71.1%，特异性分别为41.4%和51.7%。抗CFP-10抗体/M.tb特异性IFN-γ和抗ESAT-6抗体/M.tb特异性IFN-γ比值的敏感性分别为48.5%和54.6%，特异性分别为89.7%和75.9%。我们得出结论，在测量抗体反应时，QFT-GIT无刺激上清液可替代血清使用，减少此类检测所需的血量。QFT-GIT无刺激上清液中的抗体单独区分APTB和LTBI时敏感性高但特异性差，而抗体与M.tb特异性细胞因子联合使用时则相反。需要进一步探索更多的抗体及抗体/细胞因子组合，以实现更好的诊断准确性。
