A New Blood-Based Marker for Ulcerative Colitis
Serum REG3α, a protein secreted by Paneth cells, has emerged as a potential biomarker for tracking ulcerative colitis (UC) disease activity. A study published in Scientific Reports (2026) reveals that REG3α levels demonstrate a significant correlation with both clinical and endoscopic severity. By pairing this protein with C-reactive protein (CRP), researchers achieved a diagnostic accuracy that may provide a less invasive alternative to traditional stool-based monitoring, such as faecal calprotectin.
Correlation Benchmarks in Clinical Practice
The study, led by Kim SJ et al. (2026), enrolled 128 patients to weigh REG3α against established diagnostic tools. Clinical activity was defined by a total Mayo score of at least 6. The statistical correlations for these markers were as follows:
- REG3α: ρ=0.362 (p<0.001)
- CRP: ρ=0.429 (p<0.001)
- Albumin: ρ=−0.312 (p<0.001)
- Serum calprotectin: ρ=0.253 (p=0.004)
Diagnostic Performance in Endoscopy
When researchers shifted focus to endoscopic activity—defined as a Mayo endoscopic subscore of 2 or higher—the utility of specific markers diverged. While serum REG3α, CRP, and albumin maintained significant associations, serum calprotectin failed to reach statistical significance (ρ=0.147; p=0.098). By integrating REG3α and CRP, the team reached an area under the curve (AUC) of 0.847 for clinical activity and 0.783 for endoscopic activity, surpassing the efficacy of individual biomarkers.
Serial Monitoring and Patient Improvement
The potential for REG3α to guide treatment adjustments was tested in a subset of 19 patients. Follow-up measurements showed that REG3α levels dropped significantly as clinical symptoms improved (p=0.005). Despite these results, the authors caution that this sample size remains small, and clinicians should treat these findings as preliminary.
The Path Toward Clinical Validation
REG3α is a bactericidal C-type protein produced by Paneth cells in the gut, marking it as a specific indicator of epithelial damage. However, widespread clinical application remains on the horizon. The authors emphasize that larger, independent studies are required to confirm if these blood tests can reliably serve as a substitute for frequent endoscopic procedures. Future research must prioritize direct comparisons with faecal calprotectin to cement the role of these “liquid biopsies” in long-term IBD management.