Emerging Biomarkers for the Diagnosis and Monitoring of Inflammatory Bowel Diseases

Clinical Utility of the Neutrophil-to-Bilirubin Ratio in the Detection of Disease Activity in Ulcerative Colitis

Background

Ulcerative colitis (UC) is a chronic relapsing remitting form of inflammatory bowel disease (IBD). Current disease monitoring includes evaluation of symptoms, fecal calprotectin, and colonoscopy. Due to limited availability of the latter two modalities in China, we sought a readily available, inexpensive, disease monitoring laboratory assessment. We recently identified a novel serological index (the neutrophil-to-bilirubin ratio, NBR) for monitoring disease activity in Crohn's disease. However, the clinical significance has not been evaluated in UC. Here, we aimed to verify the hypothesis that NBR might be useful in monitoring clinical and endoscopic activity in patients with UC.

Methods

To test our hypothesis, we conducted a single-center, retrospective study including a total of 188 patients with UC and 145 non-IBD controls. NBR was calculated to determine its practical value in monitoring disease activity (including clinical and endoscopic activity). Disease activity of UC was determined by the partial Mayo score and the Mayo endoscopic score (MES) system.

Results

NBR was significantly higher in patients with UC than that in controls (12.10, IQR: 9.85-16.69 versus 5.06, IQR: 3.94-6.55; p < 0.001) and showed positive correlations with clinical and endoscopic disease activity in UC. Additionally, NBR was significantly lower in patients with endoscopic mucosal healing (MH) than that in those without endoscopic MH (8.81, IQR: 6.67-11.67 versus 13.51, IQR: 11.04-18.71; p < 0.001). Serial evaluation of NBR in a subset of patients demonstrated that NBR was significantly decreased during the MH stage compared with that during the endoscopically active stage.

Conclusion

Our study suggests that NBR may be a promising candidate for assessing disease activity in UC, with potential for widespread clinical use and significant clinical implications.

A Novel Neutrophil-Based Biomarker to Monitor Disease Activity and Predict Response to Infliximab Therapy in Patients With Ulcerative Colitis

Background

Ulcerative colitis (UC) is characterized by refractory and recurrent mucosal inflammation, leading to a substantial healthcare burden. Diagnostic biomarkers predicting disease activity and treatment response remain elusive. To evaluate the application value of a novel neutrophil-based index (the neutrophil-to-albumin ratio, NAR) as a novel diagnostic biomarker in patients with UC and a predictive marker for disease activity and response to infliximab (IFX) therapy.

Methods

Clinical characteristics and laboratory parameters of enrolled subjects (patients with UC and healthy controls) were retrieved from the electronic medical record database of our hospital. Serum cytokine and fecal calprotectin levels were measured by enzyme-linked immunosorbent assay (ELISA). Mucosal expression levels of inflammatory agents were measured by quantitative RT-PCR (qRT-PCR).

Results

We found that NAR, which had not yet been explored in UC, was significantly increased in patients with UC (n = 146) compared to that in controls (n = 133) (1.95 ± 0.41 vs. 1.41 ± 0.23, p < 0.0001). NAR showed a positive association with the disease activity and inflammatory load in patients with UC. Pre-treatment NAR was significantly lower in IFX responders than that in non-responders (2.18 ± 0.29 vs. 2.44 ± 0.21, p = 0.0118), showing a significant ability to discriminate initial responders from primary non-responders to IFX induction therapy (AUC = 0.7866, p = 0.0076). Moreover, pre-treatment NAR predicted postinduction serum IFX trough level.

Conclusion

Our study provides evidences to utilize NAR in the diagnosis, activity monitoring, and IFX response prediction in patients with UC.