PDCD1 and HIV-1 infection: PD-1, CTLA-4, TIM-3, LAG-3 and, TIGIT on both CD4+ and CD8+ T-lymphocytes in the peripheral blood of treatment-naïve individuals from four cohorts, including active pulmonary tuberculosis (TB), HIV-1 infection only, HIV-TB co-infected, and healthy volunteers from North India.