Difference in relapse-rate and clinical phenotype by autoantibody-subtype in Japanese patients with anti-neutrophil cytoplasmic antibody-associated vasculitis

Clinical features and prognosis of ANCA-associated vasculitis patients who were double-seropositive for myeloperoxidase-ANCA and proteinase 3-ANCA

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) patients with dual positivity for proteinase 3-ANCA (PR3-ANCA) and myeloperoxidase-ANCA (MPO-ANCA) are uncommon. We aimed to investigate these idiopathic double-positive AAV patients' clinical features, histological characteristics, and prognosis. We reviewed all the electronic medical records of patients diagnosed with AAV to obtain clinical data and renal histological information from January 2010 to December 2020 in a large center in China. Patients were assigned to the MPO-AAV group or PR3-AAV group or idiopathic double-positive AAV group by ANCA specificity. We explored features of idiopathic double-positive AAV. Of the 340 patients who fulfilled the study inclusion criteria, 159 (46.76%) were female, with a mean age of 58.41 years at the time of AAV diagnosis. Similar to MPO-AAV, idiopathic double-positive AAV patients were older and had more severe anemia, lower Birmingham Vasculitis Activity Score (BVAS) and C-reactive protein (CRP) levels, less ear, nose, and throat (ENT) involvement, higher initial serum creatinine and a lower estimated glomerular filtration rate (eGFR) when compared with PR3-AAV (P < 0.05). The proportion of normal glomeruli of idiopathic double-positive AAV was the lowest among the three groups (P < 0.05). The idiopathic double-positive AAV patients had the worst remission rate (58.8%) among the three groups (P < 0.05). The relapse rate of double-positive AAV (40.0%) was comparable with PR3-AAV (44.8%) (P > 0.05). Although there was a trend toward a higher relapse rate of idiopathic double-positive AAV (40.0%) compared with MPO-AAV (23.5%), this did not reach statistical significance (P > 0.05). The proportion of patients who progressed to ESRD was 47.1% and 44.4% in the idiopathic double-positive AAV group and MPO-AAV group respectively, without statistical significance. Long-term patient survival also varied among the three groups (P < 0.05). Idiopathic double-positive AAV is a rare clinical entity with hybrid features of MPO-AAV and PR3-AAV. MPO-AAV is the "dominant" phenotype in idiopathic double-positive AAV.

Systemic vasculitis involving the kidney: the nephropathologist's point of view

Kidneys are often targets of systemic vasculitis (SVs), being affected in many different forms and representing a possible sentinel of an underlying multi-organ condition. Renal biopsy still remains the gold standard for the identification, characterization and classification of these diseases, solving complex differential diagnosis thanks to the combined application of light microscopy (LM), immunofluorescence (IF) and electron microscopy (EM). Due to the progressively increasing complexity of renal vasculitis classification systems (e.g. pauci-immune vs immune complex related forms), a clinico-pathological approach is mandatory and adequate technical and interpretative expertise in nephropathology is required to ensure the best standard of care for our patients. In this complex background, the present review aims at summarising the current knowledge and challenges in the world of renal vasculitis, unveiling the potential role of the introduction of digital pathology in this setting, from the creation of hub-spoke networks to the future application of artificial intelligence (AI) tools to aid in the diagnostic and scoring/classification process.

Impact of different ANCA serotypes on the long-term outcome of ANCA-associated vasculitis patients

OBJECTIVES

To investigate the clinical features and long-term outcomes of Chinese anti-neutrophil cytoplasmic antibodies (ANCAs)-associated vasculitis (AAV) patients with different ANCA serotypes.

METHODS

Two hundred and twenty-four AAV patients from January 2010 to June 2021 were divided into myeloperoxidase (MPO)-ANCA and proteinase 3 (PR3)-ANCA groups. Clinical and long-term outcomes were compared.

RESULTS

In this study, the average follow-up was 46.4 months (range 0.3-188.4 months). One hundred and seventy-seven (79.0%) patients were MPO-ANCA-positive and 47 were PR3-ANCA-positive; the mean age of MPO-ANCA positive patients at diagnosis was elder than that of PR3-ANCA positive patients (67.0 vs. 60.0 years, p = .004). Among PR3-ANCA-positive patients, ear, nose and throat symptoms were more common (p = .014). Between two ANCA serotypes, there were no differences in complement 3 (C3), Birmingham vasculitis activity score (BVAS), five-factor score (FFS) or other organ involvements. For all AAV patients, the overall survival rates at one, three and five years were 80.0%, 67.0% and 56.4%, respectively. The cumulative relapse-free rates of one, three and five years were 89.5%, 76.4% and 68.4%, respectively. The survival of AAV patients was unaffected by the ANCA serotype (p = .23). The ANCA serotype also had no effect on either disease relapse (p = .20) or remission rates (p = .10). In our study, PR3-ANCA patients showed a better long-term survival, as the 5-year survival rate and the 5-year relapse-free survival rate of PR3-ANCA patients were 60.7% and 76.9%, while that of MPO-ANCA patients were 55.2% and 65.8%, respectively. Rather than ANCA serotype, younger patients with milder kidney involvement and lower disease assessment scores (BVAS and FFS) might be more relevant to better prognosis.

CONCLUSIONS

The likelihood of induced remission, patient survival or disease recurrence is all unaffected by ANCA serotypes. A better prognosis is seen in younger patients with milder kidney involvement and lower BVAS/FFS scores.

Rituximab induction and reinduction in granulomatosis with polyangiitis and microscopic polyangiitis: A retrospective multicenter study in Taiwan

OBJECTIVES

This study aimed to investigate the clinical outcomes of granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) under rituximab induction and reinduction therapy in Taiwan.

METHODS

We performed a retrospective study in patients with GPA or MPA receiving rituximab therapy from August 2008 to July 2020 in seven medical centers in Taiwan. The clinical characteristics and outcomes of these patients were analyzed.

RESULTS

In total, 53 patients (18 with GPA and 35 with MPA) were included. Kidney involvement (82.9% vs. 22.2%, p < .001) and initial creatinine (3.25 ± 2.37 vs. 1.07 ± 0.82, p < .001) were significantly higher in MPA. Within 24 weeks after the first course of rituximab, there were seven deaths (five due to infection and two due to active disease) in patients with MPA (7/35, 20%) compared to 0 in patients with GPA. Of 33 patients receiving rituximab for kidney involvement, 23 survived and were free from renal replacement therapy at 24 weeks. Their chronic kidney disease (CKD) stages improved in 2 but progressed in 7, while 24 had stable CKD stages. Death or end-stage renal disease (ESRD) was associated with infection and higher initial creatinine. Reinduction therapy for relapse was required in 18 (39.1%) of 46 survivors, which was associated with anti-proteinase 3 (PR3) positive (odds ratio 3.667, p = .049) and younger age with a cutoff of 49.4 (AUC = 0.679, p = .030, sensitivity = 66.67%, specificity = 75%).

CONCLUSION

Significant mortality occurred after rituximab induction, especially in patients with MPA. In survivors, age younger than 50 and anti-PR3 positive were associated with the risk of relapse requiring reinduction.

Old known and possible new biomarkers of ANCA-associated vasculitis

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) comprises a group of multisystem disorders involving severe, systemic, small-vessel vasculitis with short- and long term serious and life-threating complications. Despite the simplification of treatment, fundamental aspects concerning assessment of its efficacy and its adaptation to encountered complications or to the relapsing/remitting/subclinical disease course remain still unknown. The pathogenesis of AAV is complex and unique, and despite the progress achieved in the last years, much has not to be learnt. Foremost, there is still no accurate marker enabling us to monitoring disease and guide therapy. Therefore, the disease management relays often on clinical judgment and follows a" trial and error approach". In the recent years, an increasing number of new molecules s have been explored and used for this purpose including genomics, B- and T-cell subpopulations, complement system factors, cytokines, metabolomics, biospectroscopy and components of our microbiome. The aim of this review is to discuss both the role of known historical and clinically established biomarkers of AAV, as well as to highlight potential new ones, which could be used for timely diagnosis and monitoring of this devastating disease, with the goal to improve the effectiveness and ameliorate the complications of its demanding therapy.

Classification of ANCA-associated vasculitis: differences based on ANCA specificity and clinicopathologic phenotype

The classification of vasculitis according to a schema with universal acceptance is challenging, given the heterogeneous and protean nature of these diseases. Formal nomenclature and classification criteria for anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) have suffered several changes since their first description; none provides comprehensive diagnostic and classification criteria. Different factors account for the difficulties in the classification of vasculitis, including the incomplete understanding of the pathogenesis, the multisystemic nature of the disease, the non-specific patterns of vascular involvement, the overlap between entities, and the presence of various classification systems. The present article reviews the classification of AAV considering different points of view, including clinical, serologic, pathogenetic, organ predilection, therapeutic, and prognostic factors, and provides perspectives on future challenges in the understanding of AAV. There is an unmet need for a unifying view of the disease spectrum that considers the constantly evolving paradigms.

ANCA-Associated Vasculitis Clinical Presentation and Clinical Predictors of Relapse in Saudi Arabia

Background

Anti-neutrophil cytoplasm antibodies-associated vasculitis (AAV) is a rare autoimmune condition with high-relapsing rate and incidence of complications, resulting in increased morbidity and mortality. Characters of patients with anti-neutrophil cytoplasm antibodies-associated vasculitis in Saudi Arabia require further exploration.

Objective

To evaluate the clinical profile, relapse rate and disease-related complications among patients with AAV at a tertiary hospital in Saudi Arabia. To estimate the role of BVAS score at the time of presentation in predicting relapse during the disease course.

Design and Setting

This retrospective cohort study was performed through data collection from patients’ records who had AAV, who visited the rheumatology clinic. The collected data involved the demographics of patients and their investigations, medications, and outcomes of treatment. Statistical analysis was executed through SPSS version 26.

Results

Fifty-two patients were eligible for inclusion, while 48 patients were analyzed because of missing data. Females represented 60.4%. Half of the patients were more than 50 years old, and 68.8% had comorbidities. As for diagnosis, 62.5% had granulomatosis with polyangiitis, 25% had eosinophilic granulomatosis with polyangiitis, and 12.5% had microscopic polyangiitis. The rate of relapse was 31.3%, while the remission rate was 68.8%. Additionally, 66.7% had lower respiratory involvement, and 43.8% had renal involvement. More than half of the patients had BVAS score below 14.5 points. The study did not explore a positive correlation between the disease relapse and high BVAS at the first presentation.

Conclusion

Early prediction of relapse and such intervention is of paramount importance in order to avoid accrual of organ damage with treatments that prevent further relapses. BVAS score was not found to be a potential predictor in our study. Future studies are highly endorsed, with prospective design and large sample size to achieve statistical significance for the incidence of relapses and complications.

Prevalence and risk factors of relapse in patients with ANCA-associated vasculitis receiving cyclophosphamide induction: a systematic review and meta-analysis of large observational studies

BACKGROUND

Clinical relapses are common in patients with ANCA-associated vasculitis (AAV). The aim of this systematic review was to estimate time-point prevalence and risk factors of relapse.

METHODS

We searched PubMed, Embase, and Cochrane Library databases from their inception to March 30, 2020. Cohorts and post-hoc studies were included for the estimation of summary cumulative relapse rates (CRRs) and adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs). Sensitivity and meta-regression analyses were also performed.

RESULTS

Of the 42 eligible studies, 24 studies with 6236 participants were used for the pooled analyses of CRRs. The summary 1-year, 3-year, and 5-year CRRs were 0.12 (95% CI, 0.10-0.14), 0.33 (0.29-0.38), and 0.47 (0.42-0.52), respectively. In meta-regressions, the baseline age was positively associated with 1-year CRR. The proportion of granulomatosis with polyangiitis was positively associated with 5-year CRR. Twenty-eight studies with 5390 participants were used for the meta-analysis of risk factors for relapse, including a lower level of baseline serum creatine, proteinase 3 (PR3)-ANCA positivity at diagnosis, an ANCA rise, extrarenal organ involvement (including lung, cardiovascular, upper respiratory, and gastrointestinal involvement), intravenous (vs oral) cyclophosphamide induction, a shorter course of immunosuppressant maintenance, and maintenance with mycophenolate mofetil (vs azathioprine).

CONCLUSIONS

Our systematic review demonstrated that the 1-year, 3-year, and 5-year cumulative probabilities of relapse were ∼12%, 33%, and 47% in AAV patients receiving cyclophosphamide induction, respectively. Early identification of risk factors for relapse is helpful to the risk stratification of patients so as to achieve personalized treatment.

Long-term validation of the renal risk score for vasculitis in a Southern European population

Background

Recently, renal risk score on the basis of three clinicopathologic features to predict end-stage renal disease (ESRD) in antineutrophil cytoplasmic antibody (ANCA)-associated renal vasculitis has been proposed. The aim of this multi-centre study was to validate this renal risk score in a large cohort of southern European patients.

Methods

Data were retrospectively collected from the time of diagnosis by systematic review of medical records from 147 patients with renal vasculitis recruited from three Spanish centres. The renal risk score was calculated in every patient, and renal and global outcomes were analysed according to the risk group assessment.

Results

ANCA serology was positive in 76.2% of patients: 64.6% showed activity against myeloperoxidase (MPO) and 12.2% against proteinase 3 (PR3). The median (interquartile range) follow-up period was 41 months (9.6–104). Forty-eight patients (32.7%) reached ESRD. Patients were classified into the three groups according to the risk of progression to ESRD: 21.8% of patients were classified into low risk, 52.4% were classified into moderate risk and the remaining 25.9% were classified into high risk. The cumulative proportion of renal survival at 2, 5 and 10 years was 100, 100 and 82% in the low-risk group, 79, 77 and 77% in the medium-risk group and 63, 53 and 40% in the high-risk group (P < 0.001). In regression analysis, the risk score was a good predictor for the development of the ESRD among ANCA positive [hazard ratio (HR) = 2.7, 95% confidence interval (CI) 1.4–4.9; P < 0.001] and ANCA negative (HR = 2.7, 95% CI 1.04–7.1, P = 0.04) patients.

Conclusions

The renal risk score constitutes an accurate tool to predict renal outcome among patients with renal vasculitis. This study contributes to validate the risk scoring system in a MPO-predominant population, but also among ANCA-negative vasculitis patients.

Clinical impact of subgrouping ANCA-associated vasculitis according to antibody specificity beyond the clinicopathological classification

OBJECTIVES

In ANCA-associated vasculitis (AAV), classifications have emerged to individualize homogeneous clinical and outcomes patterns, including the recently defined anti-MPO granulomatosis with polyangiitis (GPA) subgroup. This study aimed to retrospectively evaluate the impacts of re-classification based on clinicopathological criteria and/or ANCA specificity.

METHODS

A retrospective monocentric study conducted at Caen University Hospital led to the identification of PR3 or MPO-ANCA AAV patients from January 2000 or September 2011, respectively, to June 2016. Eosinophilic GPA patients were excluded. AAVs were thereby also classified either as GPA or microscopic polyangiitis (MPA) according to the European Medicines Agency vasculitis algorithm.

RESULTS

A total of 150 AAV patients were included (94 GPA, 56 MPA; 87 anti-PR3 and 63 anti-MPO patients). GPA patients exhibited a worse relapse-free survival but a better renal survival (P < 0.001 and P = 0.021, respectively) than MPA patients. Overall, relapse-free and renal survival rates were similar between anti-PR3 and anti-MPO patients (P = 0.35, 0.17 and 0.15, respectively). Similarly, the prognosis was identical between anti-MPO MPA patients and anti-PR3 MPA patients (P = 0.33, 0.19 and 0.65, respectively), and between anti-MPO GPA patients and anti-PR3 GPA patients (P = 0.06, 0.99 and 0.64, respectively). Moreover, anti-PR3 GPA and anti-MPO GPA patients exhibited no differences in clinical manifestations or BVAS score.

CONCLUSION

Clinicopathological classification appeared to be the strongest criterion for distinguishing among homogeneous prognoses of AAV. Individualizing the anti-MPO GPA subgroup does not appear to bring additional value to clinical practice, but multicentre studies are required to confirm this trend.

Distinction between MPO-ANCA and PR3-ANCA-associated glomerulonephritis in Chinese patients: a retrospective single-center study

OBJECTIVES

To retrospectively investigate the clinical and histological features and outcomes of ANCA-associated glomerulonephritis (AAGN) with different ANCA serotypes.

METHOD

A total of 467 AAGN patients were divided into MPO-AAGN (MPO) and PR3-AAGN (PR3) groups according to ANCA serotype. Clinical and histological features and renal outcomes were compared.

RESULTS

In this study, 429 (91.9%) patients tested positive for MPO-ANCA, and 38 (8.1%) for PR3-ANCA. The median age at diagnosis (P = 0.017) and proportion of females (P = 0.003) were higher in the MPO group. Joint (P < 0.001), ENT (P = 0.000), skin (P = 0.007), and eye (P = 0.014) involvements were more common in the PR3 group. Compared with that in the PR3-group, a higher proportion of patients in the MPO group had microscopic polyangiitis (P = 0.000), and a lower proportion of exhibited granulomatosis with polyangiitis (P = 0.000). Patients in the MPO group also exhibited lower BVAS scores (P = 0.003) and higher serum albumin levels (P = 0.009). Histologically, a lower proportion of MPO patients had crescentic glomerulonephritis (P = 0.028) and acute tubule-interstitial lesion scores (P = 0.007), but a higher proportion of these patients exhibited mixed class glomerulonephritis (P = 0.032) than in the PR3 group. The relapse rate was lower (P = 0.020), and the 5-year relapse-free survival rate (P = 0.003) was higher in the MPO group than in the PR3 group. However, the 5-year renal survival rates (P = 0.106) were not significantly different.

CONCLUSIONS

MPO-ANCA was predominant in Chinese patients with ANCA-associated vasculitis and renal disease. The epidemiological characteristics, extra-renal involvement, and histopathological classes and outcomes were different between MPO-positive and PR3-positive patients, implying that they might be two different disease entities.

Vasculitis Pathogenesis: Can We Talk About Precision Medicine?

Precision medicine is designing the medical care by taking into account the individual variability for each person. We have tried to address whether the existing data may guide precision medicine in primary systemic vasculitides (PSV). We have reviewed genome-wide association studies (GWAS) data, lessons from monogenic mimics of these diseases, and biomarker studies in immunoglobulin A vasculitis/Henoch–Schönlein purpura, Kawasaki disease, anti-neutrophil cytoplasmic antibody-associated vasculitis, polyarteritis nodosa (PAN), Takayasu arteritis, and Behçet’s disease (BD). GWAS provide insights about the pathogenesis of PSV while whole exome sequencing studies lead to discovery of monogenic vasculitides, phenotype of which could mimic other types of vasculitis such as PAN and BD. Monogenic vasculitides form a subgroup of vasculitis which are caused by single gene alterations and discovery of these diseases has enabled more specific therapies in these patients. With increasing number of studies on biomarkers, new targets for treatment appear and better and structured follow-up of PSV patients will become possible. Proteomics and metabolomics studies are required to better categorize our patients with PSV so that we can manage them appropriately and offer more targeted therapy.

Biomarkers in vasculitis

PURPOSE OF REVIEW

Biomarkers are considered to be helpful in diagnosing, monitoring, predicting treatment response, and prognosis in clinical practice and as outcomes in clinical trials. In this article, we review the recent literature on new biomarkers and the expanding use of older ones in vasculitic conditions.

RECENT FINDINGS

In antineutrophil cytoplasmic antibody-associated vasculitis patients antineutrophil cytoplasmic antibody type may be useful as a predictor of relapse and response to rituximab. Moreover, serial measurements of proteinase-3 titer may help to predict relapse. Urinary soluble CD163 levels are promising for identifying active renal vasculitis. Imaging modalities such as positron emission tomography, computerized angiography tomography, and temporal artery ultrasound maintain their role in diagnosis and disease assessment in large vessel vasculitis. Fecal calprotectin is a useful marker of active gastrointestinal involvement in Behçet's syndrome.

SUMMARY

The publications reviewed here potentially may help to move the field of biomarkers in vasculitis management. However, more work toward understanding the underlying pathophysiology and effects of an intervention on the disease process are needed before true biomarkers can be realized. Further studies with appropriate control groups, using good definitions for disease states such as activity and remission are needed to guide our use of these markers correctly in the management of our patients.

Determinants of renal and patient outcomes in a Spanish cohort of patients with ANCA-associated vasculitis and renal involvement

The classification of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) remains controversial. The main objective of this study was to define the respective values of ANCA serotype-based classification, clinicopathological classification, and histopathological classification in predicting patient and renal outcomes in a Spanish cohort of patients with ANCA with specificity for myeloperoxidase, MPO-ANCA, versus ANCA with specificity for proteinase 3, PR3-ANCA. Two hundred and forty-five patients with ANCA-AAV and biopsy-proven renal involvement diagnosed between 2000 and 2104 were recruited in 12 nephrology services. Clinical and histologic data, renal outcomes, and mortality were analyzed. We applied the Chapel Hill Consensus Conference definition with categories for granulomatosis with the polyangiitis (GPA) and microscopic polyangiitis (MPA), the classification based on ANCA specificity, and the histopathological classification proposed in 2010. Eighty-two percent were MPO-ANCA positive and 18.0% PR3-ANCA positive. Altogether, 82.9% had MPA and 17.1% GPA. The median follow-up was 43.2 months (0.1-169.3). Neither ANCA-based serological nor clinical classification was predictive of renal outcomes or patient survival on bivariate or multivariate Cox regression analysis. Histopathological classification was found to predict development of end-stage renal disease (p = 0.005) in Kaplan-Meier analysis. ANCA specificity was more predictive of relapse than clinicopathological classification in multivariate analysis (HR 2.086; 95% CI 1.046-4.158; p = 0.037). In our Spanish cohort, a majority of patients had an MPO-ANCA-AAV. A classification based on ANCA specificity has a higher predictive value for relapse occurrence and could be used for decision-making with respect to induction treatment and maintenance therapies.