Kawasaki M, et al. - In patients with pulmonary tuberculosis (TB), researchers assessed if a novel immunoassay could assess lipoarabinomannan (LAM, a major antigen of Mycobacterium tuberculosis [MTB]) concentrations in sputum to be used as a biomarker of bacterial load prior to and during treatment. To isolate monoclonal antibodies binding to epitopes unique in LAM from MTB and slow-growing nontuberculous mycobacteria (NTM), phage display technology was used. According to findings, bacterial burden (as determined by culture prior to treatment) are associated to concentrations of sputum LAM measured by the LAM-ELISA. Notably, changes in the bacterial burden as quantified by culture are associated with changes in the concentration of sputum LAM during TB treatment.