In vivo and in vitro cell-mediated immunity in tuberculous meningitis

This study assessed in vivo and in vitro parameters of cell-mediated immunity in 45 tuberculous meningitis patients. Delayed-type hypersensitivity responses to purified protein derivative of tuberculin (PPD), Candida albicans and streptokinase-streptodornase antigens were lacking in 34 patients compared to 2 of 54 normal volunteers. Circulating T lymphocyte subpopulations (E-rosetting active and total T cells) were diminished in 41 patients studied compared to 41 normal donors (p < 0.001). Lymphocyte blast responses to PPD (25μg-500 μg/ml) were positive but quantitatively depressed in all 34 patients studied compared to PPD positive normal donors (p < 0.001). Phytohemagglutinin responses were significantly depressed (p < 0.001). Repeat studies in 20 patients 4-5 months post-therapy resulted in reversals of all parameters to control values with heightened blastogenic responses to all PPD concentrations.