Assessment of DNA aptamers targeting GlcB and HspX antigens for application in the diagnosis of abdominal tuberculosis. (May 2022)

• Record Type: Journal Article
• Authors: Kumari, Pooja; Dhiman, Abhijeet; Lavania, Surabhi; Sharma, Pratibha; Rath, Deepak; Anthwal, Divya; Gupta, Rakesh Kumar; Kochar, Archit; Sharma, Neera; Gadpayle, A.K.; Taneja, R.S.; Sharma, Lokesh; Haldar, Sagarika; Sharma, Tarun Kumar; Tyagi, Jaya Sivaswami
• Is Part Of: Tuberculosis. Volume 134(2022)
• Publication Date: 2022-05
• Subjects: Abdominal tuberculosis -- TB diagnosis -- Ascitic fluid -- Aptamer -- GlcB -- Xpert; 616.995
• DOI: 10.1016/j.tube.2022.102206
• Languages: English
• ISSNs: 1472-9792

Abstract

Abstract: The diagnosis of abdominal tuberculosis (aTB) is challenging and there is an urgent need for an accurate diagnostic test. We have developed a high affinity DNA aptamer against GlcB antigen of Mycobacterium tuberculosis (Mtb) . We further compared the diagnostic utility of in-house-generated high affinity DNA aptamers and polyclonal antibodies against two Mtb antigens, namely GlcB and HspX, in ascitic fluid samples. These diagnostic reagents were assessed in patients (n = 94) who were categorized as 'Definite TB', 'Probable TB', 'Possible TB' (taken together as aTB) and 'Non-TB' disease. Receiver operating characteristic curves were used to derive cut-off values to provide ≥93% specificity. Aptamer Linked Immobilized Sorbent Assay (ALISA) for HspX and GlcB exhibited a sensitivity of ∼84% and 50%, respectively ( p -value <0.01). In contrast, antibody-based ELISA exhibited a lower sensitivity of ∼18% and ∼28% for HspX and GlcB, respectively ( p -value <0.0001 and p = 0.05 for HspX and GlcB ELISA vs. ALISA, respectively). HspX ALISA detected 32/38 aTB cases, while Xpert detected only 9 samples. In conclusion, HspX aptamer-based test was found to be superior to the other tests for diagnosing aTB and it nearly fulfils the sensitivity criteria of WHO's 'Target Product Profile' for extrapulmonary tuberculosis (sensitivity ≥80%, specificity 98%).