Antibodies reactive with PPD are present in active and treated TB patients.

Plasma samples of from individuals infected with Mtb, with active TB disease or successfully treated TB patients and controls were tested by ELISA for the presence of IgG antibodies reactive with PPD (left), Ag85B (middle) and ESAT-6/CFP-10 (right). Ethnicity of donors was indicated using the following symbols: ‘black circle’ = West Europe; ‘black diamond’ = Est Europe; ‘black square’ = Africa; ‘black triangle’ = Asia; ‘black star’ = Sud America. Groups were compared to the uninfected controls using the Mann-Whitney test and a p< 0.05 was considered significant. * marks differences that remained significant after multiple test correction using Kruskal-Wallis testing with Dunn’s post-test.