Even though NTM exposure rarely causes a symptomatic infection in healthy individuals, this study shows that NTM carriage or transient and likely repeated exposure does elicit some of the same immune responses as MTB infection, namely down-regulation of and up-regulation of TGFβ1. In different settings and populations, these immune biomarkers have shown a potential as discriminatory diagnostic biomarkers in MTB infection and disease. Here, TGFB1 is linked to infection.