Detection of mycobacterial lipoarabinomannan with an antigen-capture ELISA in unprocessed urine of Tanzanian patients with suspected tuberculosis

Abstract

A direct antigen-capture ELISA based on the detection of mycobacterial lipoarabinomannan (LAM) in unprocessed urine was evaluated for its usefulness in clinical practice. In Tanzania, 231 patients with suspected pulmonary tuberculosis (TB) and 103 healthy volunteers were screened with standard TB tests and with the new LAM-ELISA. Of 132 patients with confirmed pulmonary mycobacterial disease (positive sputum culture), 106 were positive using the LAM-ELISA (sensitivity 80.3%). In comparison, the sensitivity of acid-fast bacilli (AFB) sputum microscopy was 62.1% (82 of 132 confirmed cases). Of the 231 patients, 17 were both culture- and AFB-negative, but had typical radiographic signs of pulmonary mycobacterial infection and did not respond to antibiotic treatment. Of these 17 patients, 13 (76.5%) had positive LAM-ELISA test results. To define the specificity of the assay, urine samples from 103 healthy volunteers were also screened using LAM-ELISA. All but one had an optical density below the cut-off (specificity 99%). Of interest was a significant correlation between level of microscopic density of mycobacteria in sputum and LAM antigen concentration in urine (chi2=8.44). The LAM-ELISA is a field-adapted tool that can improve screening standards in countries with a high incidence of TB.

Humoral immune response to Mycobactrium tuberculosis cell wall fraction and lipoarabinomannan antigens in Bangladeshi patients with active tuberculosis

“…However, we observed significantly higher IgG response against LAM in active tuberculosis cases. Similar higher IgG antibody response to LAM has been found in patients with TB and is being used as a marker for serodiagnosis of TB [4][5][6][7]9]. Significant IgG response to arabinomannan has been found following BCG vaccination indicating its role in defense against mycobacterial infection [10].…”

“…Antigen85 complex, CFP and LAM of M. tuberculosis elicits detectable IgG response in tuberculosis patients. Sensitivity and specificity of assays utilizing antibodies to LAM ranged from 80.3-93% and 91-100% respectively [4][5][6][7].…”

Detection of Mycobacterial Lipoarabinomannan with A Monoclonal Antibody Qualitative ELISA in Urine of Tuberculous Meningitis Patients

“…Boehme's and Reither's studies used different ELISA kits, although from the same manufacturer. (23,25) Reither analyzed the differences in the results of his research with the one of Boehme and came to conclusion that the manufacturer performed different producing methods for the ELISA kits. The most distinguishable difference of manufacturing method was in antibody coating method.…”

Malaria Diagnostics in Clinical Trials

“…[127][128][129][130] In addition, a urine-based Mycobacterium tuberculosis RDT using the pan-mycobacterial antigen lipoarabinomannan is being evaluated in field settings to determine its accuracy. 131,132 Evaluating prototype malaria RDTs based on this knowledge could potentially yield a POC device that could increase testing uptake by clinicians. This feature would be particularly attractive for testing children, if they and their parents have a favorable view of healthcare workers who use painless testing.…”