Diabetes mellitus co-morbidity with tuberculosis (DM + TB) as one of the common complications associated with diabetes mellitus (DM) has been verified harmful to human health. Few studies have focused on CXCL8 in DM + TB co-morbidity patients. The objective of this study was to investigate the auxiliary diagnostic value of CXCL8 in patients with DM + TB in peripheral blood. According to the inclusion and exclusion criteria, 49 DM, 45 DM + TB were enrolled as the experimental group. Fifty-eight healthy people were enrolled as the healthy control (HC) group. IFN-γ, IL-2, and other clinical indicators were obtained from the clinical laboratory. ELISA, flow cytometry, RT-qPCR and in vitro stimulation (Mycobacterium tuberculosis and glucose) were used to detect the expression of CXCL8 and related receptors in plasma and peripheral blood mononuclear cells (PBMCs). Spearman correlation analysis was used to analyze the correlation of plasma CXCL8 with disease-specific cytokines and neutrophil-related indicators in patients with DM + TB. The receiver operating characteristic (ROC) curve was used to analyze the sensitivity and specificity of CXCL8 alone or in combination with cytokines in the diagnosis of DM + TB. Plasma CXCL8 expression in DM patients was significantly higher than that of HC subjects. Compared with DM group, the expression of CXCL8, CXCR1 and CXCR2 of DM + TB was significantly increased while the expression of CXCL8 on PBMCs was not significantly different. In DM + TB, plasma CXCL8 expression was positively correlated with IFN-γ and IL-2. Cases with high CXCL8 expression were significantly associated with the higher WBC count/higher NEC percentage/higher NEC count. In addition, correlation analysis showed that CXCL8 expression was closely related to white blood cells or neutrophils in the DM + TB group. ROC analysis showed that CXCL8 alone distinguished DM and DM + TB with a sensitivity of 65.31%, a specificity of 68.89% and an AUC of 0.7265 (95%CI: 0.6225–0.8306). CXCL8 combined with IFN-γ and IL-2 had a sensitivity of 89.80%, a specificity of 88.89% and an AUC of 0.9175 (95%CI: 0.8475–0.9874) in distinguishing DM from DM + TB. Plasma CXCL8 could better distinguish DM and DM + TB patients and was correlated with IL-2, IFN-γ and neutrophil related indicators in DM + TB patients. CXCL8 alone, as well as in combination with cytokine markers, showed better diagnostic efficacy, thus providing a laboratory auxiliary diagnostic indicator for DM + TB patients. Not applicable.
Xu et al. (Tue,) studied this question.