[Diagnostic value of FCGR1B gene transcription level in active tuberculosis]

Objective: To investigate the diagnostic potential of Fc fragment of IgG receptor 1b gene (FCGR1B) transcription level in active tuberculosis. Methods: From February to September of 2018, we collected peripheral blood from patients with active tuberculosis, latent tuberculosis infection (LTBI), cured patients with tuberculosis, healthy people and patients with pneumonia in the Eighth Medical Center of PLA General Hospital. Peripheral blood mononuclear cells (PBMCs) were isolated for total RNA extraction and cDNA synthesis. The expression of FCGR1B mRNA in PBMCs was detected by quantitative real-time PCR (QPCR). Nonparametric test was used to compare the differential expression of FCGR1B mRNA between patients with active tuberculosis and control groups, and the relationships between FCGR1B mRNA expression and patient's illness condition and inflammatory indexes were analyzed by Correlation analysis. The potential of FCGR1B mRNA as a diagnostic marker for active tuberculosis was evaluated by receiver operating characteristic curve (ROC) analysis. Results: The expression of FCGR1B mRNA in PBMCs from patients with active tuberculosis was significantly increased when compared with non-tuberculosis controls, including individuals with LTBI, healthy people, cured patients with tuberculosis and patients with pneumonia (u=2 081, P<0.001). The expression of FCGR1B mRNA was higher in patients with tuberculosis who had more bacteria(H=12.35, P=0.015), and was correlated with the C-reactive protein (CRP) (r=0.30, P=0.008). ROC analysis showed that FCGR1B mRNA could distinguish active tuberculosis from non-tuberculosis with area under curve (AUC) of 0.849. The sensitivity and specificity were 71.43% and 84.17% respectively. The AUC of FCGR1B mRNA in distinguishing extra-pulmonary tuberculosis from controls was 0.906. The sensitivity and specificity were 84.62% and 91.89%, respectively. Conclusion: FCGR1B mRNA is a potential molecular marker for diagnosis of active tuberculosis.