IFNG and tuberculosis: TB patients had significantly higher proportions of IFN-γ-containing ascites CD4+ T lymphocytes after in vitro stimulation with mycobacterial antigens than non-TB patients (p = 0.0007 in response to PPD, p = 0.0003 in response to HBHA, and p = 0.0002 in response to ESAT-6, Fig 4).