Prospective monitoring of in vitro produced PR3-ANCA does not improve relapse prediction in granulomatosis with polyangiitis

Two Decades Rituximab Therapy in Anti-Neutrophil Cytoplasmic Antibody Associated Vasculitis

Remission failure and relapse numerate as one of the main problems in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAVs). The need for new agents that provide effective and safe induction accompanied by sustained remission seems to be urgent in clinical care. The efficacy and safety of rituximab (RTX) for AAVs therapy has been reported in various studies. RTX therapy offers several advantages to treating AAVs patients compared to other therapeutic approaches including reduction of Glucocorticoids (GCs) and conventional Immunosuppressive therapy (IST) usage during both the induction of remission and maintenance phases. This reduction can lead to a lower rate of serious complications making RTX therapy a safer option. It seems that RTX may provide improved clinical outcomes in these patients mediated via B-lymphocyte depletion, Proteinase 3-antineutrophilic cytoplasmic antibody (PR3-ANCA), and myeloperoxidase-antineutrophilic cytoplasmic antibody (MPO-ANCA) titers reduction. In this regard, some uncertainties have been reported to validate the association between such depletion and clinical improvement, as suggested by other sources of autoreactive B cells that did not target with RTX. Due to the prolonged B cell depletion, fixed intervals and adjusted dosage of RTX may be required in patients with AAVs. In this narrative review, we aimed to insight better understand regarding the efficacy of RTX for effective induction and sustained remission in patients with AAVs. It seems that discovering new biomarkers predicting relapse in AAVs patients can lead to future targeted therapy.

Urinary CD4 + T Cells Predict Renal Relapse in ANCA-Associated Vasculitis

SIGNIFICANCE STATEMENT

Early identification of patients at risk of renal flares in ANCA vasculitis is crucial. However, current clinical parameters have limitations in predicting renal relapse accurately. This study investigated the use of urinary CD4 + T lymphocytes as a predictive biomarker for renal flares in ANCA vasculitis. This study, including urine samples from 102 patients, found that the presence of urinary CD4 + T cells was a robust predictor of renal relapse within a 6-month time frame, with a sensitivity of 60% and a specificity of 97.8%. The diagnostic accuracy of urinary CD4 + T cells exceeded that of ANCA titers, proteinuria, and hematuria. Monitoring urinary CD4 + T lymphocytes could help assess the risk of future renal relapse, enabling early preventive measures and tailored treatment strategies.

BACKGROUND

In ANCA-associated vasculitis, there is a lack of biomarkers for predicting renal relapse. Urinary T cells have been shown to differentiate active GN from remission in ANCA-associated vasculitis, but their predictive value for renal flares remains unknown.

METHODS

The PRE-FLARED study was a prospective multicenter biomarker study including 102 individuals with ANCA-associated vasculitis in remission aimed to predict renal relapse by quantifying urinary CD4 + T-cell subsets using flow cytometry at baseline and monitoring clinical outcomes over a 6-month follow-up.

RESULTS

Among the participants, ten experienced renal relapses, two had non-renal flares, and 90 remained in stable remission. The median baseline urinary CD4 + T-cell count was significantly higher in patients who relapsed compared with those in remission. Receiver operating characteristic curve analysis of urinary CD4 + T-cell counts showed an area under the curve value of 0.88 for predicting renal flares, outperforming ANCA titers, hematuria, and proteinuria. Using a cutoff of 490 CD4 + T cells per 100 ml urine, the sensitivity and specificity in identifying patients with future renal flares were 60% and 97.8%, respectively. In a post hoc analysis, combining urinary CD4 + T-cell counts with proteinase-3 ANCA levels suggested improved predictive performance in the PR3 + subgroup. In addition, the number of urinary CD4 + T cells showed a limited correlation with a decline in GFR and an increase in proteinuria over the follow-up period.

CONCLUSIONS

This study concluded that urinary CD4 + T-cell counts could identify patients with ANCA-associated vasculitis at a substantial risk of renal relapse within 6 months. Combining these counts with ANCA levels further improved the prediction of relapse.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Urinary T Lymphocytes Predict Renal Flares in Patients With Inactive ANCA-associated Glomerulonephritis (PRE-FLARED), NCT04428398 .

Specific IgG glycosylation differences precede relapse in PR3-ANCA associated vasculitis patients with and without ANCA rise

Introduction

Immunoglobulin G (IgG) contains a conserved N-glycan in the fragment crystallizable (Fc), modulating its structure and effector functions. In anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) alterations of IgG Fc-glycosylation have been observed to correlate with the disease course. Here, we examined longitudinal changes in N-linked Fc glycans of IgG in an AAV patient cohort and their relationship with disease flares.

Methods

Using liquid chromatography coupled with mass spectrometry, we analysed IgG Fc-glycosylation in 410 longitudinal samples from 96 individuals with AAV.

Results

Analysis of the cross-sectional differences as well as longitudinal changes demonstrated that IgGs of relapsing PR3-ANCA patients have higher ΔFc-bisection at diagnosis (P = 0.004) and exhibit a decrease in Fc-sialylation prior to the relapse (P = 0.0004), discriminating them from non-relapsing patients. Most importantly, PR3-ANCA patients who experienced an ANCA rise and relapsed shortly thereafter, exhibit lower IgG Fc-fucosylation levels compared to non-relapsing patients already 9 months before relapse (P = 0.02).

Discussion

Our data indicate that IgG Fc-bisection correlates with long-term treatment outcome, while lower IgG Fc-fucosylation and sialylation associate with impending relapse. Overall, our study replicated the previously published reduction in total IgG Fc-sialylation at the time of relapse, but showed additionally that its onset precedes relapse. Furthermore, our findings on IgG fucosylation and bisection are entirely new. All these IgG Fc-glycosylation features may have the potential to predict a relapse either independently or in combination with known risk factors, such as a rise in ANCA titre.

Diagnostic accuracy of antineutrophil cytoplasmic antibodies (ANCA) in predicting relapses of ANCA-associated vasculitis: systematic review and meta-analysis

Relapse in antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) is associated with significant morbidity and mortality. Utility of ANCA for prediction of relapses is still controversial. PubMed/MEDLINE, Scopus, and WebOfScience were searched, screened and confirmed for inclusion [PROSPERO No: CRD42020220308]. Studies measuring serial ANCA by ELISA or indirect immunofluorescence (IF), reporting relapses with sufficient data to calculate sensitivity and specificity were included. Diagnostic odds ratio (OR), sensitivity, specificity and likelihood ratios (LR) were synthesized using a bivariate mixed-effect regression model. Sub-group analysis included a comparison between ELISA and IIF, anti-myeloperoxidase (MPO) and -proteinase 3(PR3), and type of rise in ANCA. For meta-analysis of survival outcomes, hazard ratios were synthesized using a random-effect model. QUADAS-2 was used for assessing quality of studies, I² statistic for heterogeneity Begg's test for publication bias. 2946 abstracts and 43 full-texts were reviewed to identify 26 eligible studies that included 2623 patients with AAV and 848 relapses. Overall heterogeneity was high [I² = 99%] and the overall risk of bias was low to moderate. ANCA positivity by either ELISA or immunofluorescence for predicting relapse of AAV had a sensitivity of 0.70(95% CI 0.58-0.81), specificity of 0.66(0.55-0.76), positive LR of 2.1(1.6-42.7) and negative LR of 0.44(0.30-0.60). ELISA performed marginally better [OR: 5(3-7)] than IIF [OR: 4(2-9)] with similar sensitivity, specificity, PLR and NLR. The area under the curve for PR3 was 0.74(0.7-0.77), while that for MPO was not computed as the number of eligible studies was only three. In the survival analysis, the hazard ratio for relapse was 3.11(1.7-5.65). The meta-analysis shows modest accuracy of ANCA in predicting relapses of ANCA vasculitis and supports the use of serial ANCA monitoring as a biomarker for relapse.

CD27+CD38hi B Cell Frequency During Remission Predicts Relapsing Disease in Granulomatosis With Polyangiitis Patients

Background: Granulomatosis with polyangiitis (GPA) patients are prone to disease relapses. We aimed to determine whether GPA patients at risk for relapse can be identified by differences in B cell subset frequencies. Methods: Eighty-five GPA patients were monitored for a median period of 3.1 years (range: 0.1-6.3). Circulating B cell subset frequencies were analyzed by flow cytometry determining the expression of CD19, CD38, and CD27. B cell subset frequencies at the time of inclusion of future-relapsing (F-R) and non-relapsing (N-R) patients were compared and related to relapse-free survival. Additionally, CD27⁺CD38^hi B cells were assessed in urine and kidney biopsies from active anti-neutrophil cytoplasmic autoantibody-associated vasculitides (AAV) patients with renal involvement. Results: Within 1.6 years, 30% of patients experienced a relapse. The CD27⁺CD38^hi B cell frequency at the time of inclusion was increased in F-R (median: 2.39%) compared to N-R patients (median: 1.03%; p = 0.0025) and a trend was found compared with the HCs (median: 1.33%; p = 0.08). This increased CD27⁺CD38^hi B cell frequency at inclusion was correlated to decreased relapse-free survival in GPA patients. In addition, 74.7% of patients with an increased CD27⁺CD38^hi B cell frequency (≥2.39%) relapsed during follow-up compared to 19.7% of patients with a CD27⁺CD38^hi B cell frequency of <2.39%. No correlations were found between CD27⁺CD38^hi B cells and ANCA levels. CD27⁺CD38^hi B cell frequencies were increased in urine compared to the circulation, and were also detected in kidney biopsies, which may indicate CD27⁺CD38^hi B cell migration during active disease. Conclusions: Our data suggests that having an increased frequency of circulating CD27⁺CD38^hi B cells during remission is related to a higher relapse risk in GPA patients, and therefore might be a potential marker to identify those GPA patients at risk for relapse.

Vasculitis research: Current trends and future perspectives

We discuss recent and prospective research in small and large vessel vasculitis. Large cohorts of Takayasu arteritis (TA) have been recently published from across the world, clarifying our understanding of this uncommon disease. Novel open-ended approaches like large-scale genotyping, proteomics and metabolomics have helped gain novel insights into TA, giant cell arteritis (GCA) and anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). Recent advances in the imaging of TA and GCA offer promise for earlier diagnosis and better monitoring of response to therapy. Although two randomized controlled trials of abatacept and tocilizumab failed to meet their primary end-points, successful large-scale studies of abatacept and tocilizumab in GCA hold promise for better disease control. While cyclophosphamide has revolutionized the management of AAV, increasing use of rituximab as an alternative induction regimen, as well as use of novel approaches involving reduced or no corticosteroid use for AAV and alternative agents such as avacopan (a complement 5a receptor antagonist) hold promise for lesser toxic induction regimens in the future. Increasingly, the risk of cardiovascular events and comorbidities such as osteoporosis are being recognized as factors affecting long-term prospects of patients with vasculitis. There is a shift in emphasis to utilize patient-reported outcomes to more accurately gauge the impact of vasculitides and their treatment.

Granulomatosis with Polyangiitis Localized in the Greater Omentum

Granulomatosis with polyangiitis (GPA) is known as anti-neutrophil cytoplasmic antibody- (ANCA-) associated small vessel vasculitis and typically manifests as pulmonary-renal syndrome, but the disease is not limited to pulmonary or renal systems. The inflammation can involve whole body organs. In addition, the ANCA titer does not always become positive. Here, we describe the case of a 91-year-old man who presented with umbilical pain and fever of unknown origin. Only the increased computed tomography value of the greater omentum suggested intra-abdominal inflammation; however, serological examinations, including the ANCA level, could not reveal the focus or cause of symptoms. Finally, the histopathological examination of specimens surgically excised from the greater omentum demonstrated GPA limited to the greater omentum. This report reminds physicians to consider GPA in the differential diagnosis of acute abdominal pain or fever of unknown origin.