Urine cytokines as biomarkers for diagnosing interstitial cystitis/bladder pain syndrome and mapping its clinical characteristics

The objective of the present study was to investigate the diagnostic values of urine cytokines in patients with interstitial cystitis/bladder pain syndrome (IC/BPS) and to identify their correlations with clinical characteristics. Urine samples were collected from 127 patients with IC/BPS [European Society for the Study of Interstitial Cystitis (ESSIC) types 1 and 2] and 28 controls. Commercially available multiplex immunoassays (MILLIPLEX map kits) were used to analyze 31 targeted cytokines. Cytokine levels between patients with IC/BPS and controls were analyzed using ANOVA. Receiver-operating characteristic curves of each cytokine to distinguish IC/BPS from controls were generated for calculation of the area under the curve. Patients with IC/BPS had urine cytokine profiles that differed from those of controls. Between patients with ESSIC type 1 and 2 IC/BPS, urine cytokine profiles were also different. Among cytokines with high diagnostic values (i.e., area under the curve > 0.7) with respect to distinguish patients with ESSIC type 2 IC/BPS from controls, regulated upon activation, normal T cell expressed and presumably secreted (RANTES), macrophage inflammatory protein (MIP)-1β, and IL-8 were of higher sensitivity, whereas macrophage chemoattractant protein (MCP)-1, chemokine (C-X-C motif) ligand 10 (CXCL10), and eotaxin-1 were of higher specificity. In multivariate logistic regression models controlling for age, sex, body mass index, and diabetes mellitus, the urine cytokines with high diagnostic values (MCP-1, RANTES, CXCL10, IL-7, and eotaxin-1) remained statistically significant in differentiating IC/BPS and controls. MCP-1, CXCL10, eotaxin-1, and RANTES were positively correlated with glomerulation grade and negatively correlated with maximal bladder capacity. In conclusion, patients with IC/BPS had urine cytokine profiles that clearly differed from those of controls. Urine cytokines might be useful as biomarkers for diagnosing IC/BPS and mapping its clinical characteristics.