Diagnostic performance of culture filtered protein 10‐specific perforin in pediatric patients with active tuberculosis

BACKGROUND: Mycobacterium tuberculosis (Mtb)‐specific perforin were significantly increased in patients with tuberculosis. This study aims to evaluate the diagnosis value of Mtb‐specific perforin in pediatric patients with tuberculosis. METHODS: Diagnostic performance of perforin levels induced by 6‐kDa early secreted antigen target (ESAT6) or culture filtered protein 10 (CFP10) were evaluated in eighty‐six samples from children participants by receiver operating characteristic curve analysis. Flow cytometry was used to detect the expression of perforin and INF‐γ of CD4(+), CD8(+) T cells in response to CFP10 stimulation. RESULTS: After ex vivo stimulation, levels of ESAT6/CFP10‐specific perforin in LTBI patients were significantly higher than active TB (ATB) patients, non‐tuberculosis infection (non‐TB), and health control (HC) individuals. The diagnostic efficacy of CFP10‐specific perforin for TB diagnosis was significantly higher than ESAT6‐specific perforin and T‐SPOT assay, and when 0.74 ng/mL was taken as the cutoff value, the sensitivity, specificity, and accuracy were 97.83%, 87.5%, and 93.02%. CFP10‐specific perforin in both CD4(+) and CD8(+) T cells were significantly higher in ATB patients compared to HCs and further increased in LTBI patients. However, INF‐γ was mainly secreted by CD4(+) T cells and showed no significant difference between LTBI and ATB patients. In addition, CFP10‐specific perforin can effectively distinguish between ATB and LTBI with the cutoff value of 1.80 ng/mL. Sensitivity and specificity were 88.46% and 85.62%, respectively. CONCLUSIONS: CFP10‐specific perforin may be used as a novel cellular immunity‐based diagnostic marker of pediatric patients with tuberculosis, and with the potential for discriminating ATB from LTBI.