Sero-diagnosis of Active Mycobacterium tuberculosis Disease among HIV Coinfected Persons using Thymidylate Kinase based Antigen and Antibody Capture Enzyme Immuno-Assays

Abstract

Background Clinical and laboratory diagnosis of Active Tuberculosis (ATB) and latent Mycobacterium Tuberculosis (M. tuberculosis) infections (LTBI) among people living with HIV/AIDS (PLWHA) presents formidable challenges. In the past, WHO issued an advisory against the use of existing TB sero-diagnostics. Emerging evidence, however, points to a precision of TB sero-diagnostics based on secretory rather than structural M. tuberculosis antigens. We hypothesized that secretory levels of M. tuberculosis thymidylate kinase (TMKmt) can Designate ATBI from LTBI and no TB (NTB). Here, we report in-house validation studies of levels of TMKmt antigen (Ag) and host specific TMKmt antibody (Ab) amongst HIV +ve and HIV −ve participants. Methods and Results Direct TMKmt Ag and host specific IgG Ab detection EIAs were conducted on broadly consented, stored serum (N=281[Ag] vs. 214 [Ab] respective) samples stratified as either HIV +ve or HIV−ve ATB relative to LTBI and No TB. On one hand, UG-peptide 1 and its PAb-based EIAs accurately diagnosed ATB relative to LTBI and NTB among HIV +ve subjects {irrespectively: (a) Ag detection ATB=OD>0.490; 95% CI: 0.7446 to 0.8715 vs. LTBI=OD<0.490; 95% CI 0.4325 to 0.4829 vs. NTB=OD<0.26; 95% CI 0.1675 to 0.2567 and (b) TMKmt specific IgG detection ATB=OD>1.00; 95% CI 1.170 to 1.528 [HIV +ve] and 2.044 to 2.978 [HIV −ve] respectively vs. LTBI=OD<1.00; 95% CI 0.2690 to 0.6396 vs. NTB=OD<; 95% CI 0.1527 to 0.8751}. HIV −ve ATB presented with Ag levels greater than NTB and less than LTBI (i.e. ATB −ve=<0.490 ODs>0.26), but displayed better ant-TMKmt IgG responses (OD>2.00; 95% CI 2.044 to 2.978) relative to HIV +ve ATB (OD<1.600; 95% CI 1.170 to 1.528); suggesting a better control of M. tuberculosis-septicemia. On the other hand, UG-peptide 2 and its PAb-based EIAs did not demonstrate ATB diagnostic potential regardless of HIV sero-status, except towards designating NTB. Conclusions TMKmt Ab and Ag detecting EIAs based on UG-peptide 1 and its derivative PAb can accurately demarcate ATB from LTBI and NTB among HIV +ve subjects.

Heme oxygenase-1 and neopterin plasma/serum levels and their role in diagnosing active and latent TB among HIV/TB co-infected patients: a cross sectional study

“…2). While the current diagnostic methods cannot distinguish between ATB and LTB, previous studies have shown several biomarkers to discriminate ATB from LTB such as LAM [17], M.tb TMK antigen [6], neopterin, and C-reactive protein [18]. However, no study had been carried out to test the diagnostic potential of HO-1 and neopterin in a sub-Saharan population.…”

“…As a result, biomarkers such as M. tb thymidylate kinase (TMKmt) antigen [6], Lipoarabinomannan(-LAM) [7], heme oxygenase 1(HO-1 [8] and neopterin [9] have been studied. Studies have shown HO-1 and neopterin to successfully distinguish LTBI from ATB [8,9].…”

Immuno-diagnosis of Mycobacterium tuberculosis in sputum, and reduction of timelines for its positive cultures to within 3 h by pathogen-specific thymidylate kinase expression assays

“…The translational significance of our results is two fold: (1) that rapid diagnostic tests (RDTs) for both TMKmt Ag and or Ab based on the micro-electro mechanical systems (MEMS) microfluidic or lateral flow immunochromatographic strip test (LFT) platforms can be used to instantaneously designate TB disease in sputum and possibly other bodily fluids such as ascites, cerebral spinal fluid, pleural effusions and lymphnode aspirates (a recent report has affirmed the ability to sero-diagnose TB among PLWHA on basis of TMKmt Ag and Ab detection EIAs done using patient blood [ 21 ]), and (2) that TMKmt mRNA or Ag detection in-culture using either microfluidic MEMS (exploiting labelled probes say forster resonance energy transfer, FRET) or LFT-RDTs respectively, can designate positive cultures within 3 h—thereby allowing the health-care workers to decide on whether or not to treat, while the patient waits within an out-patient setting. Moreover, both these can be adopted to design culture independent, rapid assays for phenotyping TB drug susceptibility and or resistance as previously anticipated [ 16 ].…”

Occurrence and Factors Associated with HIV-Sero-Discordance in Couples at Iganga General Hospital-Iganga District, Eastern Uganda

“…It may originate from a situation where one sexual partner comes into the sexual relationship already infected, or becomes infected later in life [5][6][7][8][9][10]. HIV serodiscordant is recognized as a priority for HIV prevention due to the risk of transmitting the virus to the HIVnegative partner [9][10][11][12][13][14][15]. Improvements in the effectiveness and availability of HIV treatment in recent years have enabled HIV-positive individuals to live longer and healthier [16][17][18][19][20].…”