CD69 Expression on CD4 + T Lymphocytes after In Vitro Stimulation with Tuberculin Is an Indicator of Immune Sensitization against Mycobacterium tuberculosis Antigens

Abstract

ABSTRACT The expression of the CD69 antigen on CD4 T lymphocytes after in vitro stimulation with purified protein derivative (2 tuberculin units) was used to evaluate the tuberculin reactivities of 52 individuals from four experimental groups: Mycobacterium bovis BCG-vaccinated healthy individuals with a negative tuberculin skin test (TST) result (group A), BCG-vaccinated healthy individuals with a positive TST result (group B), patients with active tuberculosis (TB) before treatment (group C), and individuals with clinically inactive TB who had previously completed a prescribed course of chemotherapy (group D). The expression of CD69 on CD4 T lymphocytes was significantly higher in patients with active TB (16.2% ± 7.3%), individuals with clinically inactive TB (10.5% ± 7.4%), and healthy individuals with a positive TST result (15.5% ± 7.2%) than in healthy individuals with a negative TST result (3.8% ± 4.3%) ( P < 0.005). We confirmed the correlation between CD69 antigen expression on T lymphocytes after stimulation with tuberculin and the TST induration diameter (Spearman rho = 0.783; P < 0.001), an assay for gamma interferon (the Quantiferon-TB assay; Spearman rho = 0.613; P < 0.001), and the lymphocyte BLAST transformation test (Spearman rho = 0.537; P < 0.001). Our results demonstrate the usefulness of the determination of CD69 on CD4 T lymphocytes after in vitro stimulation with tuberculin as a rapid indicator of immune sensitization against Mycobacterium tuberculosis .