Significance of Serum Leucine-rich Alpha-2 Glycoprotein as a Diagnostic Marker in Pediatric Inflammatory Bowel Disease

Serum leucine-rich alpha-2 glycoprotein (LRG) has been utilized for adult inflammatory bowel disease (IBD); however, its efficacy in pediatric IBD remains unknown. The aim of this study was to compare the diagnostic accuracy of serum LRG for pediatric IBD with that of current inflammatory markers, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). This retrospective case-control study included pediatric patients, aged <16 years, who underwent colonoscopy and/or esophagogastroduodenoscopy between April 2017 and March 2022. All eligible patients were divided into two groups: patients with IBD, diagnosed with ulcerative colitis and Crohn's disease, and non-IBD controls. The optimal cut-off value of serum LRG for IBD diagnosis was determined from receiver operating characteristic analysis, and diagnostic accuracy of serum LRG was compared to serum ESR and CRP. A total of 53 patients (24 with IBD and 29 non-IBD controls) met the inclusion criteria. The cut-off value of serum LRG for IBD diagnosis was determined to be 19.5 μg/ml. At this cut-off value, serum LRG had a positive predictive value (PPV) of 0.80 and negative predictive value (NPV) of 0.88. In contrast, PPV and NPV were 0.78 and 0.70 for serum ESR and 0.82 and 0.72 for serum CRP, respectively. Serum LRG can be a potential diagnostic marker for pediatric IBD, with higher diagnostic accuracy than that of the conventional serum markers ESR and CRP.

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.

Usefulness of Serum Leucine-Rich Alpha-2 Glycoprotein as a Surrogate Marker of Small Bowel Mucosal Injury in Crohn's Disease

Introduction

Although the importance of mucosal healing has been suggested in Crohn's disease, it is difficult to repeat endoscopy, especially for the entire small bowel. Recently, serum leucine-rich alpha-2 glycoprotein (LRG) has been used as a surrogate marker of endoscopy. However, few studies have investigated a correlation between LRG and mucosal injury of the entire small bowel.

Methods

We retrospectively analyzed the clinical data of 30 patients with Crohn's disease from June 2020 to August 2022 at Yamaguchi Red Cross Hospital. All the patients were surveyed through the gastrointestinal tract by esophagogastroduodenoscopy, total colonoscopy, and capsule endoscopy (CE). Subjects with mucosal injury only in the small bowel were selected. Then, we assessed the relationship between serum biomarkers (LRG, C-reactive protein [CRP], hemoglobin, albumin) and small bowel mucosal injury scores (Lewis score [LS], Capsule Endoscopy Crohn's Disease Activity Index [CECDAI], and Crohn's Disease Activity in Capsule Endoscopy [CDACE]) calculated by CE.

Results

LRG and CRP were significantly correlated with small bowel mucosal injury scores (LS, CECDAI, CDACE) (p < 0.05, Spearman's rank correlation coefficient). The degree of correlation was greater for LRG than for CRP.

Conclusions

LRG is a useful surrogate marker that closely reflects small bowel mucosal injury in the entire small bowel.

Optimal Use of Serum Leucine-Rich Alpha-2 Glycoprotein as a Biomarker for Small Bowel Lesions of Crohn's Disease

Introduction

A large proportion of small bowel lesions in Crohn's disease (CD) may exist beyond the reach of ileocolonoscopy and there is no gold standard imaging modality to screen them, suggesting the need for optimal biomarkers. We aimed to compare the usefulness of C-reactive protein (CRP), faecal calprotectin (FC), and leucine-rich alpha-2 glycoprotein (LRG) in determining small bowel lesions of CD.

Methods

This was a cross-sectional observational study. CRP, FC, and LRG were prospectively measured in patients with quiescent CD who underwent imaging examinations (capsule or balloon-assisted endoscopy, magnetic resonance enterography, or intestinal ultrasound) selected by the physician in clinical practice. Mucosal healing (MH) of the small bowel was defined as a lack of ulcers. Patients with a CD activity index >150 and active colonic lesions were excluded.

Results

A total of 65 patients (27, MH; 38, small bowel inflammation) were analysed. The area under the curve (AUC) of CRP, FC, and LRG was 0.74 (95% confidence interval: 0.61-0.87), 0.69 (0.52-0.81), and 0.77 (0.59-0.85), respectively. The AUC of FC and LRG in a subgroup of 61 patients with CRP <3 mg/L (26, MH; 32, small bowel inflammation) was 0.68 (0.50-0.81) and 0.74 (0.54-0.84), respectively. The cut-off of 16 μg/mL of LRG showed the highest positive predictive value of 1.00 with specificity of 1.00, while negative predictive value was highest (0.71) with sensitivity of 0.89 at the cut-off of 9 μg/mL.

Conclusion

LRG can accurately detect and/or exclude the small bowel lesions with two cut-off values.

Leucine-Rich Alpha-2 Glycoprotein May Be Predictive of the Adalimumab Trough Level and Antidrug Antibody Development for Patients with Inflammatory Bowel Disease: A Sub-Analysis of the PLANET Study

INTRODUCTION

The aim of this study was to examine whether biomarkers are predictive of the adalimumab (ADA) trough level and antidrug antibody development in patients with Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

Using data obtained in a prospective, multicenter, observational study (PLANET), we assessed serial changes in a novel biomarker - leucine-rich alpha-2 glycoprotein (LRG) - during ADA treatment for patients with active CD and UC. We measured serum LRG, C-reactive protein (CRP), and fecal calprotectin (fCAL) at weeks 0, 12, 24, and 52. The ADA trough level and anti-ADA antibody (AAA) were also measured at weeks 12 and 52. Correlations between the ADA trough level, AAA, and biomarkers were examined.

RESULTS

In all, 34 patients with CD and 47 patients with UC were enrolled. The ADA trough level at week 12 or at the time of ADA withdrawal was 8.5 ± 3.9 in the AAA-negative group (n = 70) and 2.9 ± 2.7 μg/mL in the AAA-positive group (n = 8) (p < 0.0001). The ADA trough level at week 12 or at the time of ADA withdrawal was associated with pretreatment LRG (p = 0.0437 and r = -0.23).

CONCLUSION

LRG, rather than CRP or fCAL, may be a marker for predicting the trough level of ADA for patients with CD and UC treated with ADA.

Leucine-rich alpha-2 glycoprotein is a potential biomarker to monitor disease activity in inflammatory bowel disease receiving adalimumab: PLANET study

BACKGROUND

This multicenter prospective study (UMIN000019958) aimed to evaluate the usefulness of serum leucin-rich alpha-2 glycoprotein (LRG) levels in monitoring disease activity in inflammatory bowel disease (IBD).

METHODS

Patients with moderate-to-severe IBD initiated on adalimumab therapy were enrolled herein. Serum LRG, C-reactive protein (CRP), and fecal calprotectin (fCal) levels were measured at week 0, 12, 24, and 52. Colonoscopy was performed at week 0, 12, and 52 for ulcerative colitis (UC), and at week 0, 24, and 52 for Crohn's disease (CD). Endoscopic activity was assessed using the Simple Endoscopic Score for Crohn's Disease (SES-CD) for CD and the Mayo endoscopic subscore (MES) for UC.

RESULTS

A total of 81 patients was enrolled. Serum LRG levels decreased along with improvements in clinical and endoscopic outcomes upon adalimumab treatment (27.4 ± 12.6 μg/ml at week 0, 15.5 ± 7.7 μg/ml at week 12, 15.7 ± 9.6 μg/ml at week 24, and 14.5 ± 6.8 μg/ml at week 52), being correlated with endoscopic activity at each time point (SES-CD: r = 0.391 at week 0, r = 0.563 at week 24, r = 0.697 at week 52; MES: r = 0.534 at week 0, r = 0.429 at week 12, r = 0.335 at week 52). Endoscopic activity better correlated with LRG compared to CRP and fCal on pooled analysis at all time points (SES-CD: LRG: r = 0.636, CRP: r = 0.402, fCal: r = 0.435; MES: LRG: r = 0.568, CRP: 0.389, fCal: r = 0.426).

CONCLUSIONS

Serum LRG is a useful biomarker of endoscopic activity both in CD and UC during the adalimumab treatment.

Leucine-rich alpha-2 glycoprotein in the cerebrospinal fluid is a potential inflammatory biomarker for meningitis

BACKGROUND

Leucine-rich alpha-2 glycoprotein (LRG) is a novel biomarker for inflammatory diseases. We evaluated the levels of LRG, interleukin (IL)-6, and tumor necrosis factor (TNF)-α in the cerebrospinal fluid (CSF) of children with meningitis.

METHODS

CSF samples from 10 patients with bacterial meningitis (BM) and 10 with aseptic meningitis (AM) were evaluated. Samples from 10 patients with febrile status (FS) were used as controls. LRG levels were measured using a two-site enzyme immunoassay. IL-6 and TNF-α levels were measured using a multiplex bead-based assay. CSF examination of patients with BM at the convalescent stage was also conducted.

RESULTS

LRG and TNF-α levels in patients with BM, and IL-6 levels in patients with BM and AM showed significant increase compared with those in FS. Patients with BM at the convalescent stage showed significantly diminished LRG and IL-6 levels. LRG and IL-6 levels in CSF were indicated to be effective predictors for BM (LRG, AUC = 0.91; IL-6, AUC = 0.85). Only LRG levels showed a significant difference between patients with BM and AM (AUC = 0.78, P = 0.034).

CONCLUSIONS

LRG level could be a sensitive inflammatory biomarker for inflammatory diseases of the central nervous system, comparable with IL-6 level.