Serum Leucine-Rich α2 Glycoprotein: A Biomarker for Predicting the Presence of Ulcerative Colitis but Not Ulcerative Proctitis

Serum Leucine-Rich α2 Glycoprotein Could Be a Useful Biomarker to Differentiate Patients with Normal Colonic Mucosa from Those with Inflammatory Bowel Disease or Other Forms of Colitis

(1) Background: Serum leucine-rich α2 glycoprotein (LRG) has been reported as a useful biomarker for monitoring disease activity in patients with inflammatory bowel disease (IBD). We investigated whether serum LRG can differentiate patients with normal colonic mucosa from those with IBD or other forms of colitis. (2) Methods: Patients with diarrhea, abdominal pain, or bloody stools were consecutively enrolled at their initial visit to our hospital. Serum LRG and C-reactive protein were measured, and a colonoscopy and histology were performed. (3) Results: We enrolled 317 patients (181 men, 136 women; median age: 51 years). Based on the endoscopic and histological criteria, 260 patients were diagnosed with ulcerative colitis (n = 134), Crohn's disease (n = 10), infectious colitis (n = 43), diverticular colitis (n = 17), or nonspecific colitis (n = 56). The remaining 57 patients were diagnosed with normal colonic mucosa including histology. The latter group's median LRG value (9.5 µg/mL, range: 5.8-13.5) was significantly lower than that of the other 260 patients (13.6 µg/mL, range: 6.8-62.7, p < 0.0001). The optimal LRG cut-off value of <10.4 µg/mL was derived from the receiver operating characteristic (ROC) curve, showing a 91% sensitivity and 77% specificity for identifying patients with normal colonic mucosa. (4) Conclusions: serum LRG values < 10.4 µg/mL could be a useful biomarker for predicting patients with normal colonic mucosa.

Novel Utility of Leucine-Rich Alpha-2-Glycoprotein as a Biomarker in Ulcerative Colitis: A Predictor of Endoscopic Remission Independent of Symptoms

Introduction

Leucine-rich alpha-2-glycoprotein (LRG) is a potential biomarker for disease activity and reflects mucosal healing in patients with ulcerative colitis (UC). However, only a few studies have described a detailed sensitivity analysis of LRG in predicting mucosal healing in patients. This study aimed to evaluate the association between LRG and the endoscopic activity of UC and its predictability for mucosal healing and explore the utility and clinical application of LRG.

Methods

The diagnostic accuracy of biomarkers, including LRG, in predicting the endoscopic activity of UC was evaluated. All consecutive patients who underwent total colonoscopy between April 2021 and September 2022 were included. The Mayo endoscopic subscore (MES) was used for assessing endoscopic activity. Furthermore, endoscopic remission was defined as an MES of ≤1. Clinical activity was evaluated based on stool frequency and bloody stool. Receiver operating characteristic curve analysis and binary logistic regression were performed to assess the diagnostic accuracy of the biomarkers. We evaluated LRG trends and treatment response in patients with MES ≥2 who underwent induction therapy.

Results

This study comprised 214 patients. The proportions of endoscopically and clinically active patients were 33.6% and 49.1%, respectively. LRG had an area under the curve (AUC) of 0.856, with a higher diagnostic accuracy than other biomarkers, such as C-reactive protein, leukocyte, neutrophil, platelet, and albumin. The cutoff value for LRG was 15.6 μg/mL (sensitivity, 72.2%; specificity, 86.6%). Using the MES, patients with higher scores had higher LRG levels than those with lower scores. The cutoff value, AUC, sensitivity, and specificity varied with a higher AUC for left-sided colitis and pancolitis than for proctitis. Logistic regression analysis showed that LRG was an independent predictor of endoscopic remission using multivariate analysis, even with the factor of clinical activity. The change ratio of LRG pre- and post-treatment was statistically significant in the higher LRG group.

Conclusion

LRG reflected endoscopic activity independently, regardless of clinical symptoms. An LRG below the cutoff value could indicate a significantly low probability of endoscopic activity in asymptomatic patients, and follow-up endoscopy (not for cancer screening) may be unnecessary. Furthermore, a higher LRG level might be more useful as an indicator of treatment efficacy.

Appropriate leucine-rich α-2 glycoprotein cut-off value for Japanese patients with ulcerative colitis

BACKGROUND

It has been suggested that serum leucine-rich α-2 glycoprotein (LRG) could be a novel monitoring biomarker for the assessment of disease activity in inflammatory bowel disease. In particular, the relationship between LRG levels and the endoscopically assessed activity of ulcerative colitis (UC) has become a matter of interest.

AIM

To clarify appropriate LRG cut-off values for the prediction of endoscopic and histologic remission in Japanese patients with UC.

METHODS

This was a cross-sectional, single-center, observational study of Japanese patients with UC. Among 213 patients with UC, in whom LRG was measured from September 2020 to February 2022, we recruited 30 patients for whom a total colonoscopy and measurements of LRG and C-reactive protein (CRP) were performed on the same day. We retrospectively analyzed correlations between the LRG and CRP levels and endoscopic indices, including the Mayo endoscopic subscore and UC endoscopic index of severity.

RESULTS

Correlations between the LRG values and the Mayo endoscopic subscore or UC endoscopic index of severity were significant (r = 0.754, P < 0.0001; r = 0.778, P < 0.0001, respectively). There were also significant correlations between CRP levels and Mayo endoscopic subscore or UC endoscopic index of severity (r = 0.599, P = 0.0005; r = 0.563, P = 0.0012, respectively), although the correlation coefficients were higher for LRG. The LRG cut-off value for predicting endoscopic remission was 13.4 μg/mL for a Mayo endoscopic subscore of 0 [area under the curve (AUC): 0.871; 95% confidence interval (CI): 0.744–0.998], and 13.4 μg/mL for an UC endoscopic index of severity of 0 or 1 (AUC: 0.904; 95%CI: 0.792–1.000).

CONCLUSION

LRG may be a surrogate marker for endoscopic activity in UC, with a cut-off value of around 13.4 μg/mL for endoscopically inactive disease.

Combined serum albumin, fecal immunochemical test, and leucine-rich alpha-2 glycoprotein levels for predicting prognosis in remitting patients with ulcerative colitis

This study investigated the usefulness of serum leucine-rich alpha-2 glycoprotein (LRG) and fecal immunochemical tests (FIT) for predicting relapse in patients with ulcerative colitis (UC). Data of 194 patients tested for LRG between January 2020 and June 2022 were retrospectively collected and clinical characteristics were recorded. LRG was strongly correlated with CRP levels and it had a moderately negative correlation with albumin levels, whereas FIT was not significantly correlated with either CRP or albumin levels. Furthermore, the median serum albumin and FIT were significantly different between patients with or without clinical relapse; while the LRG level was not associated with clinical relapse. Although LRG is not an independent factor for predicting clinical relapse, the cumulative remission rate was significantly higher in patients with higher albumin than in those with lower albumin. Furthermore, the combination of FIT and albumin was useful for predicting for relapse, patients with higher FIT and lower albumin tended to have higher relapse rates than those with both lower FIT and albumin and those with lower FIT and higher albumin. Our study indicated that serum albumin level is useful for predicting relapse, even in remitting outpatients. Although LRG is not an independent factor for predicting clinical relapse, it is useful for identifying patients that are likely to relapse when combined serum albumin or FIT results.

Serum leucine-rich alpha-2 glycoprotein in monitoring disease activity and intestinal mucosal healing for biotherapy-naïve cases with ulcerative colitis

Background and Aim

Serum leucine-rich alpha-2 glycoprotein level has been reported to be a useful biomarker in assessing mucosal healing in patients undergoing biotherapy, where mucosal lesions caused by ulcerative colitis are difficult to assess endoscopically. However, no such reports have been reported in biotherapy-naïve cases.

Methods

Sixty-eight patients with ulcerative colitis (UC) who were biotherapy-naïve at Kindai University Hospital between October 2021 and October 2022 were enrolled. We prospectively examined the correlation between leucine-rich alpha-2 glycoprotein (LRG), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and Geboes scores with clinical endoscopic activity using the Mayo endoscopic subscore (MES).

Results

Mucosal healing was achieved in 39 (57%) patients. Univariate analysis revealed that the factors associated with mucosal healing were LRG (P = 0.0024), CRP (P = 0.1078), ESR (P = 0.0372), and Geboes scores (P = 0.0075). Logistic regression analysis identified LRG and Geboes scores as independent factors associated with mucosal healing assessed using MES (P = 0.0431 for LRG and P = 0.0166 for Geboes scores).

Conclusion

LRG was found to be the easiest marker to monitor disease activity and mucosal inflammation in UC patients with biotherapy-naïve cases, with a performance equivalent to that of Geboes scores.