Background: This study aimed to develop a method for assessing the sensitivity and diagnostic performance of the neutrophil surface CD64 stimulation index (SI) in tuberculosis infection.
Methods: A total of 149 samples were divided into three groups (tuberculosis group, n = 51; nontuberculosis infection group, n = 50; and healthy control group, n = 48). Flow cytometry was used to detect the sensitivity of CD64 SI on the surface of neutrophils. The sensitivities of CD64 SI before and after stimulation with ESAT-6 and CFP-10 antigens were compared using interferon-gamma release assay-enzyme-linked immunosorbent assay (IGRA-ELISA).
Results: The diagnostic threshold for CD64 SI based on the receiver operating characteristic curve was found to be 2.025, which is the standard for judging tuberculosis infection. The IGRA-ELISA and the CD64 SI assays were highly consistent with a kappa value of 0.635 (p < 0.003, 95% CI: 0.002 - 0.003).
Conclusions: The neutrophil surface CD64 SI value detection method may serve as one of the new diagnostic methods for active Mycobacterium tuberculosis infection.