Electro-impedimetric detection of human anti-mycolate antibody biomarkers of TB before, during, and after treatment

Efficient TB management requires rapid and accurate diagnosis of active pulmonary and extrapulmonary TB at the point-of-care. Blood-based antibody biomarker assays may be ideal if unaffected by HIV co-infection and antibody memory from prior TB or vaccination. This study assessed electro-impedimetric detection (EIS-MARTI) of anti-mycolate antibodies (AMAb) in TB patients before, during, and after treatment, compared to sputum culture (MGIT) as the gold standard. A prospective pilot study enrolled 15 confirmed TB patients and 73 healthy controls at a Pretoria hospital (2016–2017). A prospective monitoring study followed 25 confirmed TB patients over 6 months of treatment at a Pretoria clinic (2019–2020) to evaluate biomarker behavior. Outcomes were analyzed using descriptive statistics, wherein diagnostic accuracy and predictive values were assessed by ROC curve analysis. EIS-MARTI detected 14/15 true TB-positive cases independent of HIV co-infection and 68/73 true TB-negatives in the pilot study. In the monitoring study, EIS-MARTI correlated with culture in 7/8 cases at treatment end, but not during the first 2 months. AMAbs arise independently of HIV co-infection in active TB, recede during treatment, and are rapidly detected by a hand-held EIS-MARTI device. While suitability for treatment monitoring remains uncertain, EIS-MARTI shows promise for rapid, accurate TB diagnosis and confirming cure. The purpose of this work was to investigate anti-mycolate antibodies as a suitable biomarker for diagnosing tuberculosis, monitoring treatment, and screening people at risk for TB.