CTLA4 and tuberculosis: In order to gain insights into the overall exhausted state in HIV-TB co-infected individuals, we evaluated the differential gene expression in terms of mRNA abundance of TIM-3, LAG-3, PD-1, CTLA-4 and TIGIT in PBMCs of recruited subjects by semi-quantitative real-time PCR assay after normalizing with housekeeping gene, β-actin.