DEVELOPMENT OF AN IFN-GAMMA RELEASE ASSAY WITH THE CAPACITY TO DIAGNOSE LATENT TUBERCULOSIS INFECTION

AMIANO NICOLAS; MARIA PAULA MORELLI; NANCY L. TATEOSIÁN; CANDELA MARTIN; GALLEGO CLAUDIO; ARMITANO RITA; STUPKA JUAN; DOMINGO J. PALMERO; A LORENA CIALLELA,; DE CASADO, GRACIELA C.; ADRIANA RODRIGUEZ MIERES; IOVANNA, JUAN L.; GARCÍA VERÓNICA

Congreso; Reunión conjunta SAIC-SAI-AAFE-NANOMED.AR, 2021; 2021

Current IFN-γ release assays (IGRAs) cannot discriminate active from latent tuberculosis infection (LTBI). Previously, we demonstrated that IFNγ secretion against Rv2626c, a Mycobacterium tuberculosis (Mtb) dormancy antigen, allows to discriminate LTBI subjects from healthy donors (HD) and tuberculosis (TB) patients. In this work we developed Diagnos-TB, a new IGRA that differentiates TB and LTBI by using a fusion protein (Fp) containing CFP10 and ESAT6 Mtb. antigens plus Rv2626c. CFP10 and ESAT6 proteins were cloned, expressed and purified in our laboratory. Diagnos-TB comprises four sterile tubes containing i) negative and ii) positive controls, iii) Fp and iv) Rv2626c proteins. Heparanized whole blood is cultured inside each tube during 16-24h and plasma IFNγ is then assayed by ELISA. According to the IFNγ levels measured, an individual can be diagnosed as a TB patient, a LTBI subject or a not infected person. We first established the cut-off for the Fp tube that differentiated infected subjects (Quatiferon-QFT+PPD+ without symptoms and TB patients) from not infected individuals (QFT-PPD-)(ROC analysis: Cut-off = 0.36IU/mL, sensitivity 85.4%, specificity = 84.4%, Area = 0.9010, p