Development of an Improved Whole Blood Assay for Diagnosis of Latent and Active Tuberculosis Cases

Background: Latent TB infection (LTBI) is an infection where the presence of disease causing organism M. tuberculosis is there without any sign and symptoms of the disease hence mostly remains undiagnosed, though Tuberculin skin test (TST) and Interferon Gamma Release Assay (IGRA) were used to diagnose the LTBI. They have their limitations, TST gives major cross-reactivity with BCG vaccine and gives inaccurate results in individuals who have taken BCG and IGRA are very costly and variable sensitivity is repeated in various populations hence the modifications are needed in the IGRA for proper diagnosis of LTBI.

Objectives: In the proposed study we aimed to develop an improved whole blood assay towards a diagnosis of latent and active TB infection as an alternative to the Quantiferon QFT assay

Methodology: Synthetic antigenic peptides against latency specific antigens will be designed and synthesized. Designed peptides will be screened for LTBI specific cytokine by in-vitro experiments. Development & production of Whole assay using selected peptides evaluation of developed assay through ELISA in clinical samples.

Expected Results: Latent specific peptides will be identified and peptide-based whole blood assay for detection and diagnosis of tuberculosis will be developed as an indigenous alternative for the existing QFT assay.

Conclusion: An improved whole blood assay will be developed for screening of LTBI in the Indian population.