The diagnostic role and clinical association of serum proteinase 3 anti-neutrophil cytoplasmic antibodies in Chinese patients with inflammatory bowel disease

Inflammatory Bowel Disease and Its Association With Perinuclear Antineutrophil Cytoplasmic Antibodies: A Systematic Review

An idiopathic condition known as inflammatory bowel disease (IBD) is characterized by a dysregulated immune response to the intestinal flora of the host. It falls into one of two primary categories: ulcerative colitis or Crohn's disease. A wide range of disorders, both clinically and genetically, can cause IBD. The purpose of this thorough analysis is to determine the significance and reliability of the correlation between perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) and IBD, as well as the implications of this correlation for the diagnosis and treatment of IBD. Ten pertinent studies were identified from a starting pool of 20 articles in this systematic review, which was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. These studies addressed treatment, complications, limitations, and outcome in addition to the presence or lack of p-ANCA in patients with IBD. In conclusion, p-ANCA is more strongly linked to inflammatory bowel illness than Crohn's disease, primarily ulcerative colitis. Some evidence suggests that there is a decrease in p-ANCA to some extent with medical or surgical interventions, but the exact intervention is not yet clear. There is less evidence suggesting that the medical or surgical treatments used in patients with IBD cause an increase or decrease in p-ANCA.

Clinical Validity of Anti-Proteinase 3 Antibodies in Patients with Inflammatory Bowel Disease: A Short Meta-Analysis

Anti-neutrophil cytoplasmic antibodies (ANCA) directed to proteinase 3 (PR3) represent highly established markers for patients with ANCA-associated vasculitis (AAV). PR3-ANCA have also demonstrated utility in the management of inflammatory bowel disease (IBD). More specifically, PR3-ANCA discriminate individuals with ulcerative colitis (UC) from Crohn's disease (CD) patients and are associated with disease severity, activity, and treatment non-response. Here, we aim to summarize the current data on the diagnostic utility of PR3-ANCA in IBD. A structured, systematic literature review, including three electronic databases, was conducted on June 6th, 2023, to identify studies assessing the diagnostic accuracy of the QUANTA Flash® PR3 assay in UC vs. CD patients. Electronic searches were supplemented by hand searching. A hierarchical, bivariate, mixed-effect meta-analysis was conducted using the metandi function, as per the Cochrane collaboration recommendations. Study quality was assessed using the QUADAS-2 tool, which considers the risk of bias and applicability. Six out of a hundred and eleven citations met the inclusion criteria and reported QUANTA Flash® PR3 diagnostic accuracy in UC vs. CD (UC, n = 667, CD, n = 682 patients). The sensitivity/specificity point estimate for UC was 34.9%/95.9%. This resulted in a Diagnostic Odds Ratio (DOR) of 12.6. The risk of bias was low in the index test and reference standard domains. Four of the six studies (67%) showed an unclear risk of bias in patient selection and in flow and timing domains. All studies had low concerns about applicability in all the domains. PR3-ANCA measured with the QUANTA Flash® PR3 assay represent novel diagnostic markers in IBD and enables discrimination between UC and CD.

Current and emerging biomarkers for ulcerative colitis

INTRODUCTION

Ulcerative colitis (UC) is a chronic illness requiring lifelong management that could be enhanced by personalizing care using biomarkers.

AREAS COVERED

The main biomarker discovery modalities are reviewed, highlighting recent results across the spectrum of applications, including diagnostics (serum anti-αvβ6 antibodies achieving an area under the curve [AUC] = 0.99; serum oncostatin M AUC = 0.94), disease activity assessment (fecal calprotectin and serum trefoil factor 3: AUC > 0.90), prognostication of the need for treatment escalation (whole blood transcriptomic panels and CLEC5A/CDH2 ratio: AUC > 0.90), prediction of treatment response, and early identification of patients with subclinical disease. The use of established biomarkers is discussed, along with new evidence regarding autoantibodies, proteins, proteomic panels, transcriptomic signatures, deoxyribonucleic acid methylation patterns, and UC-specific glycomic and metabolic disturbances.

EXPERT OPINION

Novel biomarkers will pave the way for optimized UC care. However, validation, simplification, and direct clinical translation of complex models may prove challenging. Currently, few candidates exist to assess key characteristics, such as UC susceptibility, histological disease activity, drug response, and long-term disease behavior. Further research will likely not only reveal new tools to tackle these issues but also contribute to understanding UC pathogenesis mechanisms.

Reclassification of previously diagnosed GPA patients using the 2022 ACR/EULAR classification criteria

OBJECTIVES

This study applied the 2022 criteria for granulomatosis with polyangiitis (GPA) proposed by the ACR and EULAR (the 2022 ACR/EULAR criteria) to Korean patients with previously diagnosed GPA to investigate the number of patients who could be reclassified as having GPA.

METHODS

Sixty-five patients with GPA, who met the 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides and the 2007 European Medicines Agency algorithm for GPA, were included in this study. They were reclassified based on the 2022 ACR/EULAR criteria.

RESULTS

Of the 65 patients, 48 patients (73.8%) were reclassified as having GPA. A patient could not be reclassified as having GPA if the patient did not have a total score of 5 despite granulomas on biopsy or clear GPA surrogate markers. Among the 17 patients unclassified as having GPA, 16 patients were reclassified as having MPA and one as having unclassifiable vasculitis, and furthermore, 94.1% of them harboured MPO-ANCA (or perinuclear (P)-ANCA).

CONCLUSION

The concordance rate between the 2022 ACR/EULAR criteria for GPA and the previous criteria in patients with previously diagnosed GPA was 73.8%. Although the 2022 ACR/EULAR criteria are the product of the most advanced methodologic process, it should be noted that there were some consequences of distorting the CHCC definition, and further discussion is required, especially with respect to the weightage of the items.

Role of Serum Proteinase 3 Antineutrophil Cytoplasmic Antibodies in the Diagnosis, Evaluation of Disease Severity, and Clinical Course of Ulcerative Colitis

Background/Aims

Proteinase 3 antineutrophil cytoplasmic antibody (PR3-ANCA) is a serologic marker for granulomatosis with polyangiitis. However, recent studies have also shown their role as diagnostic markers for ulcerative colitis (UC). This study was performed to investigate the clinical roles of PR3-ANCAs in the disease severity, disease extension, and clinical course of UC.

Methods

Serum PR3-ANCAs were measured in 173 UC patients including 77 patients with new-onset patients UC diagnosed within 1 month, 110 patients with Crohn’s disease, 48 patients with other intestinal diseases, and 71 healthy controls. Associations between the PR3-ANCA titer and clinical data, such as disease severity, disease extension, and clinical course, were assessed. The clinical utility of PR3-ANCA measurement was evaluated by receiver operating characteristic (ROC) analysis.

Results

PR3-ANCA ≥3.5 U/mL demonstrated 44.5% sensitivity and 95.6% specificity for the diagnosis of UC in all patients. PR3-ANCA positivity was more prevalent in the 77 new-onset UC patients (58.4%). In this group, the disease severity and extension were more severe in PR3-ANCA positive patients than in PR3-ANCA negative group (p<0.001). After treatment, the partial Mayo scores were significantly decreased with the PR3-ANCA titers. The proportion of patients who required steroids for induction therapy was significantly higher among PR3-ANCA positive than negative group. ROC analysis revealed that PR3-ANCA ≥3.5 U/mL had 75% sensitivity and 69.0% specificity for steroid requirement in new-onset UC patients.

Conclusions

Our results indicate that PR3-ANCA measurement is useful not only for diagnosing UC but also for evaluating disease severity and extension and predicting the clinical course.

Anti-glycoprotein 2 (anti-GP2) IgA and anti-neutrophil cytoplasmic antibodies to serine proteinase 3 (PR3-ANCA): antibodies to predict severe disease, poor survival and cholangiocarcinoma in primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is associated with progressive liver disease and cholangiocarcinoma. Although risk stratification is crucial for making clinical decisions, it is hindered by a scarcity of proven prognostic markers.

AIMS

To assess the value of novel anti-glycoprotein 2 (anti-GP2) and anti-neutrophil cytoplasmic antibodies to serine proteinase 3 (PR3-ANCA) in combination with PSC-specific clinical and laboratory markers as predictors of quality of life, disease severity, and cholangiocarcinoma in two large, independent cohorts of PSC patients METHODS: Discovery (338 Polish patients) and validation (178 German patients) cohorts with PSC were evaluated. Anti-GP2 (isoforms 1/4) was detected by ELISAs and PR3-ANCA by chemiluminescence immunoassay. Clinical and laboratory data were collected and analysed. The outcome was defined as liver transplantation-free survival and occurrence of cholangiocarcinoma during follow-up.

RESULTS

In the discovery group, anti-GP2_1/4 IgA and PR3-ANCA were associated with liver dysfunction, anti-GP2_1/4 IgA with risk scores for PSC and anti-GP2₄ IgA with cirrhosis. All cholangiocarcinoma patients were positive for PR3-ANCA and/or anti-GP2₄ IgA. The association between anti-GP2 IgA and liver biochemistry, risk scores, cirrhosis, impaired survival, and cholangiocarcinoma was confirmed in the validation cohort. Cox proportional-hazards regression indicated anti-GP2₁ IgA as an independent variable of poor outcome in both study cohorts. Analysis of the combined data showed that anti-GP2₄ IgA and PR3-ANCA were independent predictors for cholangiocarcinoma, while anti-GP2₁ IgA and PR3-ANCA were indicators for poor survival.

CONCLUSIONS

Anti-GP2 and PR3-ANCA are prognostic antibodies in PSC as they identify patients at risk of severe disease, poor survival and biliary cancer.