Immune Profiling Enables Stratification of Patients with Active Tuberculosis Disease or Mycobacterium tuberculosis Infection

Background: Tuberculosis (TB) is caused by Mycobacterium tuberculosis (Mtb) infection and is a major public health problem. Clinical challenges include the lack of a blood-based test for active disease. Current blood-based tests, such as QuantiFERON (QFT) do not distinguish active TB disease from asymptomatic Mtb infection. Methods: We hypothesized that TruCulture, an immunomonitoring method for whole-blood stimulation, could discriminate active disease from latent Mtb infection (LTBI). We stimulated whole blood from patients with active TB and compared with LTBI donors. Mtb-specific antigens and live bacillus Calmette-Guerin (BCG) were used as stimuli, with direct comparison to QFT. Protein analyses were performed using conventional and digital enzyme-linked immunosorbent assay (ELISA), as well as Luminex. Results: TruCulture showed discrimination of active TB cases from LTBI (P <. 0001, AUC =. 81) compared with QFT (P =. 45, AUC =. 56), based on an interferon γ(IFNγ) readout after Mtb antigen (Ag) stimulation. This result was replicated in an independent cohort (AUC =. 89). In exploratory analyses, TB stratification could be further improved by the Mtb antigen to BCG IFNγratio (P <. 0001, AUC =. 91). Finally, the combination of digital ELISA and transcriptional analysis showed that LTBI donors with high IFNγclustered with patients with TB, suggesting the possibility to identify subclinical disease. Conclusions: TruCulture offers a next-generation solution for whole-blood stimulation and immunomonitoring with the possibility to discriminate active and latent infection.