Detection Of Lipoarabinomannan In Urine Research Articles

Complementary Nonsputum Diagnostic Testing for Tuberculosis in People with HIV Using Oral Swab PCR and Urine Lipoarabinomannan Detection

Complementary Nonsputum Diagnostic Testing for Tuberculosis in People with HIV Using Oral Swab PCR and Urine Lipoarabinomannan Detection

Complementary Nonsputum Diagnostic Testing for Tuberculosis in People with HIV Using Oral Swab PCR and Urine Lipoarabinomannan Detection.

Testing for mycobacterial lipoarabinomannan (LAM) in urine is a practical but insensitive alternative to sputum testing to diagnose tuberculosis (TB) in people with HIV (PWH). Here, we evaluated urine LAM testing alongside PCR-based tests for Mycobacterium tuberculosis (MTB) DNA in tongue swabs. We hypothesized that the two nonsputum samples would deliver complementary, not redundant, results. The study included 131 South African patients of whom 64 (48.1%) were confirmed to have TB by GeneXpert MTB/RIF Ultra (Xpert Ultra) or culture analysis of sputum. A total of 120 patients (91.6%) were coinfected with HIV and 130 yielded a valid urine LAM result (Alere DETERMINE LAM Ag). Tongue swab samples were tested by IS6110-targeted qPCR with a quantification cycle (Cq) cutoff of 32. Relative to reference sputum testing (TB culture and Xpert Ultra), combined urine LAM and oral swab testing (either sample positive) was significantly more sensitive than either nonsputum sample alone (57% sensitivity for combined testing versus 35% and 39% sensitivity for urine LAM and tongue swabs; P = 0.01 and 0.04, respectively). Specificity of combined testing (neither sample positive) was 97%. On average, tongue swab-positive participants had higher sputum signal strength than urine-LAM positive participants, as measured by sputum Xpert Ultra Cq value (P = 0.037). A subset of tongue swabs (N = 18) was also tested by using Xpert Ultra, which reproduced true positive and true negative IS6110 qPCR results and resolved the two false-positive tongue swabs. With further development, tongue swabs and urine may feasibly serve as complementary nonsputum samples for diagnosis of TB in PWH.

Diagnostic value of Lipoarabinomannan antigen for detecting Mycobacterium tuberculosis in adults and children with or without HIV infection

ObjectivesEven today, tuberculosis (TB) remains a leading public health problem; yet, the current diagnostic methods still have a few shortcomings. Lipoarabinomannan (LAM) provides an opportunity for TB diagnosis, and urine LAM detection seems to have a promising and widely applicable prospect.Design or methodsFour databases were systematically searched for eligible studies, and the quality of the studies was evaluated using the quality assessment of diagnostic accuracy studies‐2 (QUADAS‐2). Graphs and tables were created to show sensitivity, specificity, likelihood ratios, diagnostic odds ratio (DOR), the area under the curve (AUC), and so on.ResultsBased on the included 67 studies, the pooled sensitivity of urine LAM was 48% and specificity was 89%. In the subgroup analyses, the FujiLAM test had higher sensitivity (69%) and specificity (92%). Furthermore, among patients infected with human immunodeficiency virus (HIV), 50% of TB patients were diagnosed using a urine LAM test. Besides, the CD4+ cell count was inversely proportional to the sensitivity.ConclusionsUrine LAM is a promising diagnostic test for TB, particularly using the FujiLAM in HIV‐infected adults whose CD4+ cell count is ≤100 per μl. Besides, the urine LAM test shows various sensitivities and specificities in different subgroups in terms of age, HIV infection status, CD4+ cell count, and testing method.

Significant Improvement in Tuberculosis Diagnosis by Detection of the Wall <i>Lipoarabinomannan</i> from <i>Mycobacterium tuberculosis</i> in Central African Republic (CAR)

Background and Objective: Tuberculosis is one of the leading causes of morbi-mortality, especially in developing countries, due to delayed diagnosis and management. The goal of this study is to assess the contribution of lipoarabinomannan (LAM) in improving tuberculosis (TB) diagnosis in the Central African Republic (C.A.R.). Methods: We conducted a retrospective study at the the Regional University Hospital of Bria. The records of patients hospitalized, tested by Determine® TB LAM Antigen Ag (Alere, Medical Co, LTD, Chiba, Japan) immunochromatographic test for the detection of LAM in urine, associated or not with acid-fast bacilli (AFB) research by Ziehl-Neelsen stain, were selected from August to October 2020. Results: During this study, 152 files were selected. Among them, there were 50.0% of children aged 14 or less (≤14 years: 33.6% + 16.4%) and 50.0% of adults represented. Patients living in the displaced person camp represented a larger group (65.1%) than those in the other 2 sites. There were seventy-four patients (i.e 48.7%) who did not benefit from screening for AFB. For the other seventy-eight (i.e. 51.3%), there were 17.1% positive results for the search of AFB. However, among the 152 patients, there was a positive HIV serology in 30.9% of cases (i.e. 47 out of 152) and a positive Determine® TB LAM Ag in 38.2% of cases (i.e. 58 out of 152). It appears that Determine® TB LAM Ag was significantly more able to diagnose tuberculosis than AFB (p 0.003). The 58 patients diagnosed with TB LAM included 20 children who could not provide sputum and HIV-infected patients (p 0.03). Conclusion: The results of this study showed that the microscopy for AFB made it possible to make the diagnosis of tuberculosis in 17.1% of patients against 38.2% for the Alere Determine® TB LAM Ag test. This result highlights the need for routine use of LAM detection to improve the diagnosis of tuberculosis. The conduct of a subsequent study combining Xpert MTB/RIF would improve the diagnosis of tuberculosis using all 3 tests.

Detection of lipoarabinomannan in urine and serum of HIV-positive and HIV-negative TB suspects using an improved capture-enzyme linked immuno absorbent assay and gas chromatography/mass spectrometry

TB diagnosis and treatment monitoring in resource limited regions rely heavily on serial sputum smear microscopy and bacterial culture. These microbiological methods are time-consuming, expensive and lack adequate sensitivity. The WHO states that improved TB diagnosis and treatment is imperative to achieve an end to the TB epidemic by 2030. Commercially available lipoarabinomannan (LAM) detection tools perform at low sensitivity that are highly dependent on the underlying immunological status of the patient; those with advanced HIV infection perform well. In this study, we have applied two novel strategies towards the sensitive diagnosis of TB infection based on LAM: Capture ELISA to detect LAM in paired urine and serum samples using murine and human monoclonal antibodies, essentially relying on LAM as an ‘immuno-marker’; and, secondly, detection of α-d-arabinofuranose and tuberculostearic acid (TBSA)- ‘chemical-markers’ unique to mycobacterial cell wall polysaccharides/lipoglycans by our recently developed gas chromatography/mass spectrometry (GC/MS) method. Blinded urine specimens, with microbiologically confirmed active pulmonary TB or non TB (HIV+/HIV–) were tested by the aforementioned assays. LAM in patient urine was detected in a concentration range of 3–28 ng/mL based on GC/MS detection of the two LAM-surrogates, d-arabinose and tuberculostearic acid (TBSA) correctly classifying TB status with sensitivity > 99% and specificity = 84%. The ELISA assay had high sensitivity (98%) and specificity (92%) and the results were in agreement with GC/MS analysis. Both tests performed well in their present form particularly for HIV-negative/TB-positive urine samples. Among the HIV+/TB+ samples, 52% were found to have >10 ng/mL urinary LAM. The detected amounts of LAM present in the urine samples also appears to be associated with the gradation of the sputum smear, linking elevated LAM levels with higher mycobacterial burden (odds ratio = 1.08–1.43; p = 0.002). In this small set, ELISA was also applied to parallel serum samples confirming that serum could be an additional reservoir for developing a LAM-based immunoassay for diagnosis of TB.

A sensitive urinary lipoarabinomannan test for tuberculosis.

We have previously developed a diagnostic test for tuberculosis based on detection of mycobacterial lipoarabinomannan (LAM) in urine. The method depended on a laborious concentration step. We have now developed an easy to perform test based on a magnetic immunoassay platform, utilizing high avidity monoclonal antibodies for the detection of LAM in urine. With this method the analytical sensitivity of the assay was increased 50-100-fold compared to conventional ELISA. In a pilot study of HIV-negative patients with microbiologically verified TB (n=17) and healthy controls (n=22) the sensitivity of the test was 82% and the specificity 100%. This is in stark positive contrast to a range of studies using available commercial tests with polyclonal anti-LAM Abs where the sensitivity of the tests in HIV-negative TB patients was very low.

Detection of lipoarabinomannan in urine for identification of active tuberculosis among HIV‐positive adults in Ethiopian health centres

To assess the diagnostic performance of urine lipoarabinomannan (LAM) detection for TB screening in HIV-positive adults in Ethiopia. Testing for LAM was performed using the Determine TB-LAM lateral flow assay on urine samples from participants in a prospective cohort with baseline bacteriological categorisation for active TB in sputum. Characteristics of TB patients with regard to LAM status were determined. Participants were followed for 6months to evaluate survival, retention in care and incident TB. Positive LAM results were found in 78/757 participants. Among 128 subjects with definite (confirmed by culture and/or Xpert MTB/RIF) TB, 33 were LAM-positive (25.8%); the respective figure for clinically diagnosed cases was 2/20 (10%). Five of the remaining 43 LAM-positive individuals had died during the 6-month follow-up period, whereas 38 remained in care without clinical signs of TB. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 25.8%, 92.9%, 42.3% and 86.0%, respectively. Among TB patients, LAM positivity was associated with higher WHO clinical stage, lower body mass index (BMI), CD4 cell and haemoglobin levels, and with increased mortality. A combination algorithm of urine LAM testing and sputum smear microscopy detected 49 (38.2%) of definite TB cases; among those with CD4 count ≤100cells/mm3 , this proportion was 66.7%. The performance of urine LAM testing for TB detection was poor in this population. However, this was improved among subjects with CD4 count ≤100cells/mm3 . In combination with sputum microscopy urine, LAM could be considered for targeted TB screening in this subgroup.

Lipoarabinomannan enzyme-linked immunosorbent assay for early diagnosis of childhood tuberculous meningitis

Tuberculous meningitis (TBM) is a severe complication of tuberculosis (TB) predominantly affecting young children. Early initiation of treatment is important to prevent morbidity and mortality associated with TBM, emphasising the importance of early diagnosis. Among the most promising new methods for diagnosing TB are antigen-detection assays based on the detection of lipoarabinomannan (LAM). To evaluate the diagnostic value of a commercial, antigen-capture enzyme-linked immunosorbent assay (ELISA) test based on the detection of LAM in urine for the early diagnosis of TBM in children. A cross-sectional study in which urine samples from paediatric patients with suspected TBM attending the Tygerberg Children's Hospital, Cape Town, South Africa, were tested for LAM. Complete data were available for 50 of 56 patients with suspected TBM. TBM was diagnosed in 21 (42%) patients and excluded in 29 (58%). The LAM ELISA had a sensitivity of 4.8% and a specificity of 93.1%. Serial measurements in the first 2 weeks after treatment initiation did not improve test performance. We have shown that urinary LAM detection was of little value for the diagnosis of TBM in a cohort of paediatric patients with suspected TBM.

Association of lipoarabinomannan with high density lipoprotein in blood: Implications for diagnostics

Understanding the pathophysiology of tuberculosis, and the bio-distribution of pathogen-associated molecules in the host is essential for the development of efficient methods of intervention. One of the key virulence factors in the pathology of tuberculosis infection is Lipoarabinomannan (LAM). Previously, we have demonstrated the reliable detection of LAM in urine from tuberculosis patients in a sandwich immunoassay format. We have also applied an ultra-sensitive detection strategy developed for amphiphilic biomarkers, membrane insertion, to the detection of LAM with a limit of detection of 10 fM. Herein, we evaluate the application of membrane insertion to the detection of LAM in patient serum, and demonstrate that the circulating concentrations of 'monomeric' LAM in serum are very low, despite significantly higher concentrations in the urine. Using spiked samples, we demonstrate that this discrepancy is due to the association of LAM with high-density lipoprotein (HDL) nanodiscs in human serum. Indeed, pull-down of HDL nanodiscs from human serum allows for the recovery of HDL-associated LAM. These studies suggest that LAM is likely associated with carrier molecules such as HDL in the blood of patients infected with tuberculosis. This phenomenon may not be limited to LAM in that many pathogen-associated molecular patterns like LAM are amphiphilic in nature and may also be associated with host lipid carriers. Such interactions are likely to affect host-pathogen interactions, pathogen bio-distribution and clearance in the host, and must be thoroughly understood for the effective design of vaccines and diagnostics.

Rapid detection of Mycobacterium tuberculosis biomarkers in a sandwich immunoassay format using a waveguide-based optical biosensor

Early diagnosis of active tuberculosis (TB) remains an elusive challenge, especially in individuals with disseminated TB and HIV co-infection. Recent studies have shown a promise for the direct detection of pathogen-specific biomarkers such as lipoarabinomannan (LAM) for the diagnosis of TB in HIV-positive individuals. Currently, traditional immunoassay platforms that suffer from poor sensitivity and high non-specific interactions are used for the detection of such biomarkers. In this manuscript, we demonstrate the development of sandwich immunoassays for the direct detection of three TB-specific biomarkers, namely LAM, early secretory antigenic target 6 (ESAT6) and antigen 85 complex (Ag85), using a waveguide-based optical biosensor platform. Combining detection within the evanescent field of a planar optical waveguide with functional surfaces that reduce non-specific interactions allows for the ultra-sensitive and quantitative detection of biomarkers (an order of magnitude enhanced sensitivity, as compared to plate-based ELISA) in complex patient samples (urine, serum) within a short time. We also demonstrate the detection of LAM in urine from a small sample of subjects being treated for TB using this approach with excellent sensitivity and 100% corroboration with disease status. These results suggest that pathogen-specific biomarkers can be applied for the rapid and effective diagnosis of disease. It is likely that detection of a combination of biomarkers offers greater reliability of diagnosis, rather than detection of any single pathogen biomarker. NCT00341601.

Quantitative Analysis of a Urine-Based Assay for Detection of Lipoarabinomannan in Patients with Tuberculosis

Urinary lipoarabinomannan (LAM) detection is a promising approach for rapid diagnosis of active tuberculosis (TB). In microbiologically confirmed TB patients, quantitative LAM detection results increased progressively with bacillary burden and immunosuppression. Patients with disseminated TB and/or advanced HIV are target populations for whom urine LAM detection may be particularly useful.