Classification of antineutrophil cytoplasmic autoantibody vasculitides: the role of antineutrophil cytoplasmic autoantibody specificity for myeloperoxidase or proteinase 3 in disease recognition and prognosis

Sustained Remission of Granulomatosis With Polyangiitis After Discontinuation of Glucocorticoids and Immunosuppressant Therapy: Data From the French Vasculitis Study Group Registry

OBJECTIVE

Data on sustained remission of granulomatosis with polyangiitis (GPA) after discontinuation of therapy (referred to as GPA with sustained remission off-therapy [SROT]) are scarce. In the present study, SROT among GPA patients from the French Vasculitis Study Group Registry was evaluated to identify factors associated with its occurrence and durability.

METHODS

For inclusion of patients in the study, the diagnosis of GPA had to meet the GPA classification criteria defined by the American College of Rheumatology and/or the revised Chapel Hill Consensus Conference nomenclature for vasculitis. SROT was defined as achievement of remission (a Birmingham Vasculitis Activity Score of 0) that was sustained for ≥6 consecutive months after having discontinued glucocorticoid (GC) and immunosuppressant treatments. The characteristics of the patients at baseline and treatments received were compared at 3, 5, and 10 years postdiagnosis according to whether or not SROT had been reached and maintained.

RESULTS

Among 795 patients with GPA, 92 GPA patients with SROT at 3 years postdiagnosis were compared to 342 control subjects who had experienced disease relapse and/or were still receiving GCs or immunosuppressants. No baseline differences were found, but patients with SROT at 3 years postdiagnosis had more frequently received intravenous cyclophosphamide as induction therapy compared to control subjects (P = 0.01), with a higher median number of infusions (P = 0.05). At 5 years postdiagnosis, no baseline differences were observed between groups, but patients with SROT at 5 years postdiagnosis had received more cyclophosphamide infusions compared to control subjects (P = 0.03). More patients with SROT had received rituximab as maintenance therapy than control subjects at 3 years and 5 years postdiagnosis (P = 0.09 and P < 0.001, respectively). Of the 74 patients enrolled in the GPA Registry with 10-year follow-up data after having received conventional maintenance therapy, 15 (20%) had reached SROT at 3 years, and 5 (7%) maintained SROT at 10 years postdiagnosis.

CONCLUSION

After conventional therapies, 7% of GPA patients had reached SROT at 10 years postdiagnosis. No baseline vasculitis characteristics distinguished patients who achieved/maintained SROT from those who experienced disease relapse and/or those who continued to receive GCs or immunosuppressant therapy, but patients with SROT had received more intensive induction therapy and rituximab as maintenance therapy more frequently.

Clinical Utility of Serial Measurements of Antineutrophil Cytoplasmic Antibodies Targeting Proteinase 3 in ANCA-Associated Vasculitis

Background: The utility of ANCA testing as an indicator of disease activity in ANCA-associated vasculitis (AAV) remains controversial. This study aimed to determine the association of ANCA testing by various methods and subsequent remission and examine the utility of a widely used automated addressable laser-bead immunoassay (ALBIA) to predict disease relapses.

Methods: Data from the Rituximab vs. Cyclophosphamide for ANCA-Associated Vasculitis (RAVE) trial were used. ANCA testing was performed by direct ELISA, capture ELISA, and ALBIA. Cox proportional hazards regression models were used to evaluate the association of PR3-ANCA level and subsequent remission or relapse. The ALBIA results are routinely reported as >8 when the value is high. For this study, samples were further titrated. A decrease and increase in PR3-ANCA were defined as a halving or doubling in value, respectively.

Results: A decrease in ANCA by ALBIA at 2 months was associated with shorter time to sustained remission (HR 4.52, p = 0.035). A decrease in ANCA by direct ELISA at 4 months was associated with decreased time to sustained remission (HR 1.77, p = 0.050). There were no other associations between ANCA decreases or negativity and time to remission. An increase in PR3-ANCA by ALBIA was found in 78 of 93 subjects (84%). Eleven (14%) had a PR3-ANCA value which required titration for detection of an increase. An increase of ANCA by ALBIA was associated with severe relapse across various subgroups.

Conclusions: A decrease in ANCA by ALBIA at 2 months and by direct ELISA at 4 months may be predictive of subsequent remission. These results should be confirmed in a separate cohort with similarly protocolized sample and clinical data collection. A routinely used automated ALBIA for PR3-ANCA measurement is comparable to direct ELISA in predicting relapse in PR3-AAV. Without titration, 14% of the increases detected by ALBIA would have been missed. Titration is recommended when this assay is used for disease monitoring. The association of an increase in PR3-ANCA with the risk of subsequent relapse remains complex and is affected by disease phenotype and remission induction agent.

Severe infections in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis: a retrospective cohort study with a clinical phenotype approach

Severe infections are common in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We aimed to describe the characteristics of patients with AAV and severe infections according to clinical phenotype. Retrospective cohort study including patients with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). Baseline characteristics were compared between patients with and without at least one severe infection. Demographics, comorbidities, clinical characteristics, laboratory and treatment were retrieved at diagnosis and at every infectious event. One hundred and eight patients were included (57 with and 51 without infections). Patients with an infection had received more frequently methylprednisolone boluses at AAV diagnosis than patients without infections (OR 2.6, 95% CI 1.1-5.9, p = 0.01). There were a total of 108 severe infections in 57 patients (median follow-up 18 months). Thirty-two patients (56%) had an infectious complication within the first year of AAV diagnosis, 43 (75%) had pulmonary involvement during the first infection. The most frequent type of infection was pneumonia. Phenotypes were: Non-severe AAV (n = 11), severe PR3-AAV (n = 30), severe MPO-AAV (n = 9); the number of infectious events in each group was 11, 69, 18, respectively. Patients with severe MPO phenotype were older and required more frequently ICU stay compared to other phenotypes. Positive correlation was found between total of infections and pulmonary infiltrates due to vasculitis (ρ = 0.40, p = 0.003), endobronchial involvement (ρ = 0.40, p = 0.003), and alveolar hemorrhage (ρ = 0.34, p = 0.015). Severe infections, most commonly pneumonia, were frequent in this cohort, especially during the first year after diagnosis, in patients with pulmonary involvement and severe PR3 phenotype who received methylprednisolone boluses.

Rituximab maintenance therapy for patients with antineutrophil cytoplasmic antibody-associated vasculitis in Japan

OBJECTIVES

We examined the efficacy and safety of rituximab (RTX) maintenance therapy for patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in Japan.

METHODS

We conducted a retrospective study using a multi-center cohort database of vasculitis patients. All maintenance treatment courses were divided into three groups: a RTX group, a group treated with other immunosuppressant drugs (IS) and a group receiving glucocorticoid monotherapy (GC). The primary endpoint was the comparison of relapse-free survival after 1 year. We also analyzed the occurrence of severe adverse events (SAEs) to assess safety.

RESULTS

We included 123 courses of 107 patients (RTX n = 14, IS n = 64, GC n = 45). Twelve of 14 in the RTX group patients were diagnosed with granulomatosis with polyangiitis (GPA). The relapse-free survival of RTX maintenance therapy was comparable to that in the other groups (p = .122). After 1 year of treatment, the RTX group was administered lower steroid doses and one-third of them could withdraw corticosteroid. The overall incidence of SAE was 0.54/patient-year in the RTX group, 0.39/patient-year in the IS group and 0.34/patient-year in the GC group.

CONCLUSION

RTX maintenance therapy could be effective and safe in Japanese GPA patients.

Urinary soluble CD163 as a biomarker of disease activity and relapse in antineutrophil cytoplasm antibody-associated glomerulonephritis

Background

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis is a chronic relapsing and remitting autoimmune disease. Urinary soluble CD163 (usCD163) has been proposed as a biomarker of active renal vasculitis. We aimed to assess the potential usefulness of usCD163 for diagnosing renal relapse in patients with ANCA-associated glomerulonephritis.

Methods

One hundred and fifty-six samples from 47 patients with ANCA-associated glomerulonephritis belonging to two different cohorts (incident and prevalent) and 20 healthy controls were studied. Patients from the incident cohort were prospectively followed up, and usCD163 concentrations were measured every 3 months. Renal relapses were identified and changes in usCD163 concentrations were analysed.

Results

Normalized usCD163 concentrations were elevated at disease onset in all patients with active renal vasculitis, with a median concentration of 601 ng/mmol (interquartile range 221–1404 ng/mmol). On the other hand, usCD163 concentrations were undetectable among control patients with renal vasculitis in remission. Except for non-responders, usCD163 concentrations progressively decreased in all patients after treatment. In the presence of vasculitis relapse, there was a consistent increase in usCD163 concentrations, compared with previous values. The area under the receiver-operating characteristic curve of absolute and relative changes in usCD163 concentrations to identify relapse of ANCA-associated glomerulonephritis was 0.96 [95% confidence interval (CI) 0.91–1.00; P = 0.001] and 0.95 (95% CI 0.90–1.00; P = 0.001), respectively. Sensitivity and specificity for a relative increase of 20%, or an absolute increase of 20 ng/mmol, in usCD163 concentrations were 100% for both, and 89.3% and 87.5%, respectively. Urinary sCD163 concentrations significantly correlated with Birmingham Vasculitis Activity Score scores at Month 6 (r = 0.737; P = 0.006) and Month 12 (r = 0.804; P = 0.005).

Conclusions

usCD163 represents an accurate biomarker for the detection of active renal vasculitis and relapse. Its close association with disease activity provides additional information for monitoring treatment response.

Glomerular Diseases Associated with Malignancies: Histopathological Pattern and Association with Circulating Autoantibodies

Aim: Glomerular diseases (GD) associated with malignancies (AM, GDAM) have unique features, which are important to recognize, in the light of the progress made in cancer therapy. We aimed to describe the clinical and histopathological characteristics of patients with GDAM in relation to the presence of circulating autoantibodies, pointing to potential immune pathogenic pathways connecting cancer to GD. Materials and Methods: The included patients were studied retrospectively on the basis of a kidney biopsy proving GD and a related biopsy to establish the diagnosis of AM. We recorded patients’ demographics, serological and laboratory parameters, histopathological findings, and the type of malignancy, GD, and therapy. Results: In total, 41 patients with GDAM, with a mean age of 63.1 (±10.7) years, were studied. In 28 (68.3%) cases, GD was associated with a solid tumor, and in 13 (31.7%) patients with a lymphoid malignancy. The most frequent histopathological pattern was membranous nephropathy (43.9%). Overall, at the time of GD diagnosis, 17% of the patients were positive for antinuclear antibodies (ANA), and 12.2% for antineutrophil cytoplasmic autoantibodies (ANCA), all against myeloperoxidase (MPO). In addition, 93.3% of the patients who had membranous nephropathy were negative for transmembrane glycoprotein M-type phospholipase A₂ receptor (PLA₂R) antibody. Sixteen patients (39.0%) presented with acute nephritic syndrome, of whom five (31.25%) developed rapidly progressive glomerulonephritis. In a mean follow-up time of 36.1 (±28.3) months, nine (21.95%) patients ended up with end-stage kidney disease, and eight (19.5%) died. Conclusion: We found that 3.2% of patients who underwent a native kidney biopsy in our institution during the past decade, for any reason, were identified as having some type of GD associated with a malignancy. Serology indicated a significant presence of ANA or MPO-ANCA antibodies in patients with nephritic syndrome and the absence of PLA₂R antibodies in patients with membranous nephropathy.

Anti-neutrophil cytoplasmic antibodies (ANCA): Antigen interactions and downstream effects

Neutrophils are the most abundant leukocytes in circulation and are key "first responders" in the immune response to infectious and non-infectious stimuli. Unlike other immune cells, neutrophils can mount a robust response (including a change in surface markers and the production of extracellular traps and reactive oxygen species) just minutes after sensing a disturbance. It has been speculated that, in some individuals, the activation of neutrophils inadvertently leads to the generation of anti-neutrophil cytoplasmic autoantibodies (ANCA) against particular neutrophil proteins (antigens) such as myeloperoxidase (MPO) and proteinase 3 (PR3). In these individuals, continuous ANCA-antigen interactions are thought to drive persistent activation of neutrophils, chronic immune activation, and disease, most notably, small vessel vasculitis. There are significant gaps however in our understanding of the underlying mechanisms and even the pathogenicity of ANCA given that vasculitis can develop in the absence of ANCA, and that ANCA have been found in circulation in other conditions with no apparent contribution to disease. These gaps are particularly evident in the context of human studies. Herein, we review knowledge on neutrophil-derived ANCA antigens PR3 and MPO, ANCA generation, and ANCA-antigen interaction(s) that may promote immune activation and disease.

Microscopic Polyangiitis Initially Presumed to Be Endocarditis

The antineutrophil cytoplasmic antibody- (ANCA-) associated vasculitides (AAVs), which include fever of unknown origin (FUO), are rare diseases characterized by necrotizing inflammation of small blood vessels and the presence of ANCAs. Microscopic polyangiitis (MPA) is a subtype of the AAVs. Although the prevalence of AAVs has generally increased over the last 20 years, there have been rare reports from the dental and oral surgery field. In this article, we present a case of MPA suspected to be infective endocarditis (IE) following tooth extraction.

Update on the Management of Respiratory Manifestations of the Antineutrophil Cytoplasmic Antibodies-Associated Vasculitides

Antibody-associated vasculitis comprises 3 small vessel vasculitis syndromes: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic polyangiitis (EGPA). This article outlines the major tracheobronchial and pulmonary parenchymal disease manifestations of GPA and MPA and their management, as well as relevant recent advances in the treatment of EGPA. Shared trends in the management of all 3 syndromes are: (1) a focus on glucocorticoid avoidance and (2) an increasing reliance on biologic agents. Evidence from randomized controlled trials and large cohort studies in support of these trends as well as ongoing research efforts are summarized.

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.

Management of ANCA associated vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) is a small to medium vessel vasculitis associated with excess morbidity and mortality. This review explores how management of AAV has evolved over the past two decades with pivotal randomized controlled trials shaping the management of induction and maintenance of remission. Contemporary AAV care is characterized by approaches that minimize the cumulative exposure to cyclophosphamide and glucocorticoids, increasingly use rituximab for remission induction and maintenance, and consider therapies with less toxicity (for example, methotrexate, mycophenolate mofetil) for manifestations of AAV that do not threaten organ function or survival. Simultaneously, improvements in outcomes, such as renal and overall survival, have been observed. Additional trials and observational studies evaluating the comparative effectiveness of agents for AAV in various patient subgroups are needed. Prospective studies are necessary to assess the effect of psychosocial interventions on patient reported outcomes in AAV. Despite the expanding array of treatments for AAV, little guidance on how to personalize AAV care is available to physicians.

Long-term outcome of renal transplantation in childhood-onset anti-neutrophil cytoplasmic antibody-associated vasculitis

BACKGROUND

There have been a few reports of RTx for AAV in children; however, post-transplant recurrence rate and long-term prognosis remain unclear. Here, we describe the long-term outcomes of RTx in childhood-onset AAV.

METHODS

We conducted a retrospective study of children who underwent RTx for AAV between 1999 and 2017 and had a follow-up period of >2 years.

RESULTS

Seven patients consisting of three children with MPA and four with RLV were analyzed. Age at Dx was 5.9 (median; range, 4.1-14.5) years. PD was instituted in all patients, and median time on dialysis was 26 (range, 14-63) months. Age at RTx was 12.8 (median; range, 8.7-16.3) years. There were no recurrences of AAV noted during the median follow-up period of 7.0 (range, 2.7-18.8) years after RTx. Graft loss occurred in one patient due to non-adherence. Estimated glomerular filtration rate of the remaining patients at the last follow-up was 73.0 (median; range, 50.7-93.9) mL/min/1.73 m² . No malignancies and deaths occurred during the observational period.

CONCLUSIONS

Our study suggests that RTx for AAV with ESRD is a potentially safe and effective treatment choice for children with AAV.

Splenic infarction is not rare in granulomatosis with polyangiitis

Splenic involvement is rarely reported in patients with ANCA-associated vasculitides (AAVs), particularly in those with granulomatosis with polyangiitis (GPA) and is in fact considered to be underestimated. We aimed to investigate the frequency of splenic lesions-mainly infarction-and related factors in patients with AAVs. Patients with AAV whose abdominal or thoracic computed tomographies (CTs) were performed at or after diagnosis were included in the study. CT images were examined for splenic lesions. Overall, 69 patients (median age at diagnosis 54 [IQR 24] years; 55% with GPA, 29% with microscopic polyangiitis, and 16% with renal-limited disease) were included in the analysis. Splenic pathologies were detected in 19 (28%) patients; 12/19 (63%) splenomegaly and 7/19 (37%) splenic infarction. All patients with splenic infarction exhibited GPA with PR3-ANCA-positive serology. Three of these seven patients had autosplenectomy. Patients with splenic infarction were younger at diagnosis (p = 0.018) with also significantly higher ear-nose-throat (ENT) (%100 vs 37; p = 0.002) and eye involvement (%50 vs %12; p = 0.044) than patients without splenic infarction. Splenic pathologies are not rare in AAVs. Furthermore, infarction can help separate GPA from MPA. In young patients with GPA, particularly those with ENT and eye involvements, physicians should consider splenic infarction.Key Points• Splenic infarction is more common than previously thought in ANCA-associated vasculitides, particularly in granulomatosis with polyangiitis.• Detecting splenic infarction can help differentiate granulomatosis with polyangiitis from other subgroups.

Renal Transplantation in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: Current Perspectives

BACKGROUND

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is the leading cause of rapidly progressive glomerulonephritis, which may follow an unfavorable disease course. Despite therapeutic advances, a number of patients with AAV will eventually develop end-stage renal disease (ESRD). Renal transplantation (RTx) is associated with a survival benefit and improves quality of life in patients with ESRD.

SUMMARY

In recent years, RTx has been increasingly used also in patients with vasculitis. The posttransplant patient- and graft-survival rates in AAV were at least comparable to other diagnoses in most studies. Prior to transplantation, patients should be in stable remission for 12 months. Persistent ANCA positivity does not exclude patients from the waiting list. Even though the recurrence risk is generally low with modern posttransplant immunosuppression, including mycophenolate mofetil and tacrolimus, patients with AAV, particularly those with positive antiproteinase-3 ANCA who may have increased risk of relapse or recurrence of the disease, require constant surveillance. Similar to treatment of relapsing disease in the nontransplant setting, rituximab may become treatment of choice for posttransplant recurrences. Key Messages: RTx is the preferred renal replacement therapy of choice for AAV patients with ESRD. It is recommended that patients should be in remission for about 12 months prior to proceeding with RTx. ANCA positivity alone is not a contraindication for transplantation. The risk of relapse posttransplantation is minimal with currently used posttransplant immunosuppressive regimen.

Autoantibody Biomarkers in Rheumatic Diseases

Autoantibodies encountered in patients with systemic rheumatic diseases bear clinical significance as a biomarker to help or predict diagnosis, clinical phenotypes, prognosis, and treatment decision-making. Furthermore, evidence has accumulated regarding the active involvement of disease-specific or disease-associated autoantibodies in the pathogenic process beyond simple association with the disease, and such knowledge has become essential for us to better understand the clinical value of autoantibodies as a biomarker. This review will focus on the current update on the autoantibodies of four rheumatic diseases (rheumatoid arthritis, myositis, systemic sclerosis, and anti-neutrophil cytoplasmic antibody associated vasculitis) where there has been a tremendous progress in our understanding on their biological effects and clinical use.

Proteinase-3 and myeloperoxidase serotype in relation to demographic factors and geographic distribution in anti-neutrophil cytoplasmic antibody-associated glomerulonephritis

Background

In anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis, antigen specificity varies between myeloperoxidase (MPO) and proteinase 3 (PR3). This has been reported to vary in relation to age, gender, geography and extrarenal manifestations. However, studies are difficult to compare as criteria for inclusion vary. The aim of this study was to investigate the relationship between ANCA serotype, latitude, ultraviolet (UV) radiation levels, age, gender and renal function at diagnosis in a large study with uniform inclusion criteria.

Methods

Patients with biopsy-proven ANCA-associated glomerulonephritis were identified from regional or nationwide registries in 14 centres in Norway, Sweden, the UK, the Czech Republic, Croatia, Italy and the USA during the period 2000-13. UV radiation levels for 2000-13 in Europe were obtained from the Swedish Meteorological and Hydrological Institute.

Results

A total of 1408 patients (45.2% PR3-ANCA) were included in the study. In univariable analysis, PR3-ANCA was significantly associated with male gender {odds ratio [OR] 2.12 [95% confidence interval (CI) 1.71-2.62]}, younger age [OR per year 0.97 (95% CI 0.96-0.98)] and higher glomerular filtration rate [OR per mL/min 1.01 (95% CI 1.01-1.02); P < 0.001] at diagnosis but not with latitude or UV radiation. In multivariable logistic regression analysis, latitude and UV radiation also became significant, with higher odds for PR3-ANCA positivity at northern latitudes/lower UV radiation levels. However, the latitudinal difference in MPO:PR3 ratio is smaller than differences previously reported concerning microscopic polyangiitis and granulomatosis with polyangiitis.

Conclusions

The ratio between PR3-ANCA and MPO-ANCA varies in glomerulonephritis with respect to age, gender, renal function and geographic latitude/UV radiation levels.

Evaluation of PR3-ANCA Status After Rituximab for ANCA-Associated Vasculitis

INTRODUCTION

The value of antineutrophil cytoplasmic antibody (ANCA) measurements among patients with an established diagnosis of ANCA-associated vasculitis (AAV) to assess disease activity or predict relapse remains controversial, but recent evidence suggests a possible role for rituximab-treated patients.

PATIENTS AND METHODS

All patients with active vasculitis and positive proteinase 3 (PR3)-ANCA who were starting a 2-year treatment course of rituximab for induction of remission at Addenbrooke's Hospital between January 2011 and January 2016 were included in this study. Common department practice consists of 6 g of rituximab given over 2 years, concomitant corticosteroids (0.5-1.0 mg/kg) with rapid taper over 3 months, and cessation of oral maintenance immunosuppressive agents at time of first rituximab dose. Clinical and laboratory data were collected retrospectively using electronic patient records.

RESULTS

Fifty-seven patients with current PR3-ANCA positivity were included in the analysis. Median follow-up was 59 months. PR3-ANCA negativity was achieved in 25 patients (44%) with a median time of 14 months. Clinical remission was achieved in 53 patients (93%) with a median time of 3 months. Among the 53 patients who achieved remission during follow-up, 24 (45%) relapsed with a median time to relapse of 36 months from remission. Both PR3-ANCA-negative status and 50% reduction in PR3-ANCA from baseline (as time-varying covariates) were significantly associated with a longer time to relapse (PR3-ANCA-negative status: hazards ratio, 0.08 [95% confidence interval, 0.01-0.63, p = 0.016]; 50% reduction in PR3-ANCA: hazards ratio, 0.25 [95% confidence interval, 0.18-0.99, p = 0.046]).

CONCLUSIONS

Achieving and maintaining PR3-ANCA negativity after rituximab was associated with longer-lasting remission.

Management and treatment of glomerular diseases (part 2): conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

In November 2017, the Kidney Disease: Improving Global Outcomes (KDIGO) initiative brought a diverse panel of experts in glomerular diseases together to discuss the 2012 KDIGO glomerulonephritis guideline in the context of new developments and insights that had occurred over the years since its publication. During this KDIGO Controversies Conference on Glomerular Diseases, the group examined data on disease pathogenesis, biomarkers, and treatments to identify areas of consensus and areas of controversy. This report summarizes the discussions on primary podocytopathies, lupus nephritis, anti-neutrophil cytoplasmic antibody-associated nephritis, complement-mediated kidney diseases, and monoclonal gammopathies of renal significance.

Anti-neutrophil Cytoplasmic Antibodies (ANCA) as Disease Activity Biomarkers in a "Personalized Medicine Approach" in ANCA-Associated Vasculitis

PURPOSE OF REVIEW

ANCA-associated vasculitides (AAV) are a group of rare diseases characterized by blood vessel inflammation and the presence of circulating anti-neutrophil cytoplasmic antibodies recognizing proteinase-3 (PR3) (PR3-ANCA) or myeloperoxidase (MPO), MPO-ANCA.

RECENT FINDINGS

Historically, ANCAs have been used as biomarkers for disease associations and increases of ANCA levels as predictors of relapse in patients with AAV. In this review, we will summarize and highlight the most recent developments for using ANCA as predictive biomarkers and review some of the important disease-specific features in patients with AAV.

Personalized Medicine in ANCA-Associated Vasculitis ANCA Specificity as the Guide?

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a small- to medium-vessel necrotizing vasculitis responsible for excess morbidity and mortality (1). The AAVs, which include granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA), are among the most difficult types of vasculitis to treat. Although clinicopathologic disease definitions have been used traditionally to categorize patients into one of these three diagnoses, more recently ANCA specificity for either proteinase 3 (PR3) or myeloperoxidase (MPO) has been advocated for the purpose of disease classification (2). This is because differences in genetics, pathogenesis, risk factors, treatment responses, and outcomes align more closely with PR3- or MPO-ANCA type than with the clinocopathologic diagnosis. Moreover, classifying patients as GPA or MPA can be challenging because biopsies are not obtained routinely in most cases and existing classification systems can provide discrepant classification for the same patient (3). In this review, we address the recent literature supporting the use of ANCA specificity to study and personalize the care of AAV patients (Table 1). We focus particularly on patients with GPA or MPA.

Disease heterogeneity in antineutrophil cytoplasmic antibody-associated vasculitis: implications for therapeutic approaches

In recent decades, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis has transformed from an almost uniformly fatal disease to a treatable form of primary systemic vasculitis. Substantial disease heterogeneity exists within ANCA-associated vasculitis and the increasing understanding of this heterogeneity has implications for guiding treatment decisions. Approaches to induction and maintenance therapy vary depending on disease severity, clinical manifestations, and patient-specific factors. In this narrative Review, we examine how disease heterogeneity in ANCA-associated vasculitis, with respect to disease severity, clinical presentations, and ANCA specificity, influences therapeutic decision making. Many questions regarding therapeutic strategies in ANCA-associated vasculitis remain unanswered, and these should guide future research in this complex group of diseases.

Remission maintenance in ANCA-associated vasculitis: does one size fit all?

Introduction: The majority of the patients with anti-neutrophil cytoplasmic autoantibody (ANCA) associated vasculitis (AAV) achieve remission with effective induction therapy. Therefore, prevention of relapses and avoiding long-term damage and treatment-related toxicity are major challenges.Areas covered: This review provides an update on maintenance therapy in AAV, emphasizing the available treatment options for granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). Among the spectrum of all patients with AAV, those at higher risk of relapse have recently been identified. Clinical trials have yielded robust results about various options for maintenance of remission including common disease-modifying anti-rheumatic drugs (DMARDs, i.e. azathioprine, methotrexate, and mycophenolate mofetil) and rituximab (RTX). However, outcomes of these studies are not easy to compare.Expert opinion: Regardless of the treatment used, patients presenting with an anti-proteinase-3 ANCA, relapsing GPA have a substantially higher risk of relapse compared to patients with newly diagnosed MPA or positive anti-myeloperoxidase ANCA. While the efficacy of common DMARDs for remission maintenance is heterogeneous, the role of RTX seems particularly promising for the high-risk patients, although the most appropriate dose and timing of retreatment with RTX remain under controversial. Low-dose glucocorticoid use for remission maintenance versus complete discontinuation also remains under investigation.

Detection by flow cytometry of anti-neutrophil cytoplasmic antibodies in a novel approach based on neutrophil extracellular traps

BACKGROUND

Anti-neutrophil-cytoplasmic antibodies (ANCA) are auto-antibodies directed against components of neutrophil granulocytes and may be found in various inflammatory conditions, like small-vessel vasculitis or ulcerative colitis (UC). Routine ANCA screening is performed on ethanol-fixed neutrophils using indirect immunofluorescence technique. Yet, how neutrophil granule proteins become available to immunologic presentation is a matter of debate. In recent years, various studies have shown that neutrophils are able to extrude their chromatin decorated with granular proteins as neutrophil extracelullar traps (NETs).

AIM

We hypothesized that (I) ANCA immunoreactivity may be found on NETs and (II) NETs may serve as a useful tool in a novel approach for ANCA detection.

METHODS

Sera from patients suffering from either ANCA-associated vasculitis (n = 10), UC (n = 30) or sera from patients without diagnosed ANCA-associated diseases (n = 20), respectively, were subjected to indirect immunofluorescence and a newly developed method to detect ANCA by flow cytometry employing microbead technology.

RESULTS

ANCA-related immunofluorescence was readily detectable on ethanol-fixed NETs, establishing NETs as a structure carrying ANCA target antigens. Moreover, we observed that neutrophils form NETs in response to microbeads and stick to the surface of these beads. Using these NET-coated microbeads in flow cytometry, we were capable of reliably detecting p-ANCA, c-ANCA, and a-ANCA in tested patient sera. UC-related complex DNase-1-sensitive ANCA (NET-ANCA) antigens were also detected on NET-coated microbeads.

CONCLUSION

NET-coated microbeads may be commercially developed as a novel tool for automated ANCA screening assays using flow cytometry.

Measuring Circulating Complement Activation Products in Myeloperoxidase- and Proteinase 3-Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

There is accumulating evidence that complement activation is important in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) pathogenesis. This study was undertaken to investigate complement activation in AAV with myeloperoxidase (MPO) positivity and AAV with proteinase 3 (PR3) positivity after determining optimal methods for measuring activated complement factors in circulation.

METHODS

Participants included 98 patients with AAV (45 MPO-ANCA positive, 53 PR3-ANCA positive) and 35 healthy controls. Plasma was obtained from blood collected using EDTA tubes, with or without 100 μg/ml Futhan. Levels of Bb, C3a, C5a, soluble C5b-9 (sC5b-9), properdin, and C4d were measured by enzyme-linked immunosorbent assay. Group comparisons were made using Wilcoxon's 2-sample test. Paired data were analyzed using a matched pairs signed rank test.

RESULTS

Compared to healthy controls, certain complement analyte levels were high in patients with active AAV with MPO positivity, including C3a (P < 0.0001), C5a (P = 0.0004), and sC5b-9 (P = 0.0007). During remission, levels of Bb (P = 0.001), C3a (P < 0.0001), and sC5b-9 (P = 0.003) were higher. Compared to healthy controls, C3a (P < 0.0001), C5a (P = 0.002), sC5b-9 (P = 0.0001), and C4d (P = 0.005) levels were higher in patients with active AAV with PR3 positivity; levels of C3a (P < 0.0001) and C4d (P = 0.007) were also higher duriing remission. There were no significant differences in any complement analyte for either ANCA serotype between patients with active disease and those with disease in remission. Among patients with paired samples, sC5-9 levels were significantly lower during disease remission compared to active disease. C5a was significantly lower among patients with disease in long-term remission who were not receiving therapy. For Bb, C5a, and sC5b-9, median levels and individual values were considerably higher in control and patient samples processed without Futhan compared to those processed with Futhan.

CONCLUSION

Complement activation occurs in both MPO-positive AAV and PR3-positive AAV. The complement activation profile differs according to disease activity and possibly ANCA serotype. Futhan reduces in vitro complement activation and provides a more accurate measurement.

Clinical characteristics of patients with vasculitis positive for anti-neutrophil cytoplasmic antibody targeting both proteinase 3 and myeloperoxidase: a retrospective study

Anti-neutrophil cytoplasmic antibody (ANCA) may target proteinase 3 (PR3) or myeloperoxidase (MPO). Although a few patients with vasculitis have both MPO- and PR3-ANCA, the details of their clinical characteristics are not known. The objective of this study was to analyze the characteristics of patients with dual MPO- and PR3-ANCA-positive vasculitis. The medical records of patients with ANCA and vasculitis confirmed by biopsy were reviewed. The age at diagnosis, sex, and data on organ involvement of the kidney, lung, upper airways, skin, nervous system, and gastrointestinal tract were collected. Clinical variables were analyzed according to ANCA specificity. Of 85 patients with ANCA and vasculitis included in this study, 67 (78.8%) had MPO-ANCA, 10 (11.8%) had PR3-ANCA, and 8 (9.4%) had both MPO- and PR3-ANCA. Patients with MPO- PR3 + ANCA-associated vasculitis (AAV) were younger at diagnosis (median, 54.4 years; p < 0.05) than patients with MPO + PR3- AAV (67.0 years) or dual-ANCA AAV (MPO + PR3 + , 68.5 years). The initial glomerular filtration rate in patients with MPO + PR3- AAV (22.0 ml/min) was significantly lower than that in patients with MPO- PR3 + AAV (108.6 ml/min, p < 0.05), but was not different from that in dual-ANCA AAV patients (16.5 ml/min). Upper airway involvement also differed with ANCA type (MPO+ PR3- , 35.8% vs. MPO- PR3 + , 70.0% vs. MPO + PR3+ , 75.0%, p < 0.05). The involvement of other organs did not differ according to ANCA type. Age at diagnosis, kidney involvement, and upper airway involvement were associated with ANCA type. Patients with dual-ANCA-positive vasculitis had considerably more kidney dysfunction than patients with MPO- PR3+ AAV. They also had more upper airway involvement than patients with MPO+ PR3- AAV.

The Association of Airway Comorbidities With the Clinical Phenotypes and Outcomes of Patients With Antineutrophil Cytoplasmic Autoantibody-associated Vasculitis

OBJECTIVE

We investigated the association of airway comorbidities with the clinical phenotypes and outcomes of myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCA)-positive ANCA-associated vasculitis (AAV).

METHODS

An AAV patient multicenter cohort trial was established in 13 hospitals in western Japan between 2012 and 2018. We examined 143 of the new-onset MPO-ANCA-positive AAV patients. Their clinical characteristics and comorbidities at disease onset were compared based on clinical phenotypes. Multivariate analysis was performed to identify factors predictive of remission and death.

RESULTS

Twenty-seven cases with granulomatosis with polyangiitis (GPA), 10 with eosinophilic GPA (EGPA), 81 with microscopic polyangiitis (MPA), and 25 with unclassified AAV were identified. The average age of MPO-ANCA-positive patients was 71.4 years. Comorbidity (87.4%) and airway comorbidity (70.6%) were frequently observed in these patients. Examination of the clinical phenotypes revealed that the cases of GPA were frequently accompanied by infectious airway comorbidity (upper airway disease, bronchiectasis, pulmonary infections), and most of the cases of MPA and unclassified AAV were accompanied by fibrotic interstitial lung disease (fILD) or emphysema. Among MPO-ANCA-positive patients, infectious airway comorbidity was predictive of both remission (HR 1.58, P = 0.03) and mortality (HR 2.64, P = 0.04), and fILD was predictive of mortality (HR 7.55, P = 0.008). The combination of infectious airway comorbidities and fILD caused the worst survival outcomes in patients.

CONCLUSION

MPO-ANCA-positive AAV was frequently accompanied by airway comorbidities. In addition to fILD, infectious airway comorbidities were closely associated with those clinical phenotypes and outcomes.

Overview of the Vasculitides

The systemic vasculitides are heterogeneous clinicopathologic disorders that share the common feature of vascular inflammation. The resulting disorder can vary depending on involvement of specific organs, caliber of blood vessels, the underlying inflammatory process, and individual host factors. The cumulative result is diminished blood flow, vascular alterations, and eventual occlusion with variable ischemia, necrosis, and tissue damage. An international revised nomenclature system provides the necessary nosology and findings relevant to classify each of the vasculitides. This article is an introduction and overview of the clinical presentation, differential diagnosis, laboratory evaluation, and treatment of systemic and nervous system vasculitides.

The complexity of classifying ANCA-associated small-vessel vasculitis in actual clinical practice: data from a multicenter retrospective survey

The different sets of criteria for diagnosis or classification of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) lead to numerous overlapping and reclassified diagnoses in clinical practice. We designed this study to assess the difficulties in classifying patients with AAV. As a secondary objective, different variables were tested to predict prognosis. We conducted a retrospective chart review in a Western Spain multicentre survey. A total of 115 adult patients diagnosed with AAV from 2002 to 2013 and followed for at least 3 years were included. They were classified according to (1) Chapel Hill Consensus Conference (CHCC), (2) European Medicines Agency algorithm and (3) French Vasculitis Study Group/European Vasculitis Society phenotypes. Fifty-three patients (46%) had neither distinctive histopathological data of a single AAV definition nor any surrogate markers for granulomatous inflammation and thus did not fulfill any diagnostic criteria. Ocular, ear, nose, throat, skin, and lung involvement were more frequent with proteinase 3 (PR3) antibodies, whereas peripheral neuropathy was more frequent with myeloperoxidase (MPO) antibodies. When the disease was severe at diagnosis, the HR for mortality was 10.44. When induction treatment was not given in accordance with the guidelines, the HR for mortality was 4.00. For maintenance treatment, the HR was 5.49 for mortality and 2.48 for relapse. AAV classification is difficult because many patients had neither specific clinical data nor distinctive histological features of a single CHCC definition. A structured clinical assessment of patient severity is the best tool to guide the management of AAV.

Eosinophilic Granulomatosis with Polyangiitis: Experiences in Korean Patients

Eosinophilic granulomatosis with polyangiitis (EGPA) is one form of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Identical to what has been called Churg-Strauss syndrome, EGPA exhibits both allergic and vasculitis features. EGPA was first described as a syndrome consisting of asthma, fever, eosinophilia, and organ involvement including heart failure, neuropathy, and kidney damage, by Churg and Strauss in 1951. On the basis of the 2012 Chapel Hill Consensus Conferences Nomenclature of Vasculitis, EGPA comprises three typical allergic components, including asthma, peripheral eosinophilia, and eosinophil-rich granuloma of the respiratory tracts. EGPA has three clinical and histological stages. The first is an allergic stage composed of asthma and sinusitis, and the second is an eosinophilic stage characterised by peripheral hypereosinophilia and intra-organ infiltration of eosinophils. The last is a vasculitic stage, including necrotising inflammation of small vessels and end-organ damage. In this review, we describe the classification criteria for EGPA and recommendations for the evaluation and management of EGPA with conventional and newly suggested drugs for EGPA. Also, we discuss a variety of clinical aspects such as predictive values for prognosis and associations with other Th2-mediated diseases and hepatitis B virus.

Antineutrophil cytoplasmic antibodies and their relationship with disease activity and presence of staphylococcal superantigens in nasal swabs in patients having granulomatosis with polyangiitis: results of a study involving 115 patients from a single center

OBJECTIVE

Antineutrophil cytoplasmic antibodies (ANCAs) are considered a risk factor for granulomatosis with polyangiitis (GPA) exacerbation, especially when staphylococcal superantigens (SAgs) are present in nasal swabs. Their role in monitoring disease activity remains controversial. This study determined the relationship of ANCAs with disease activity and presence of SAgs in GPA patients.

METHODS

Among a total of 115 GPA patients hospitalized in the period 2009-2016, we investigated the presence of SAgs and ANCA concentration. Blood samples and nasal swabs were taken at each visit (referred further to as episodes). Disease activity was assessed using the Birmingham Vasculitis Activity Score (BVAS).

RESULTS

We analyzed 362 episodes. ANCAs were detected in 215 (59.4%), while SAgs were detected in 126 (34.8%) episodes. We found a significant correlation between the presence of ANCAs and disease activity (p = 0.0032), as well as between their level and GPA severity (r = 0.25363, p = 0.000001). We also determined that an ANCA values ≥ 138 Ru/ml were an indicator of active disease with high specificity and low sensitivity (84.4% and 37.3%, respectively). The relationship between ANCA presence and the presence of SAgs was not confirmed; however, when SAgs were analyzed based on the different types, ANCA levels were found to be significantly higher in the group with SAg type B (p = 0.031).

CONCLUSIONS

There was no detectable evidence for the association between ANCA level and the presence of SAgs. Although monitoring ANCA levels as a marker of disease activity may be clinically relevant, GPA management cannot proceed on the basis of ANCA levels alone. Key Points • ANCA concentration usually correlates with GPA activity, although in half of patients, ANCAs persist despite effective treatment and clinical remission. • ANCA values of 138 Ru/ml seem to be an indicator of active disease with high specificity, but low sensitivity. • Although there is a relevance for ANCA monitoring as a marker of disease activity, GPA management cannot be based on ANCA levels alone. • The suspected clinical correlation between ANCA formation and SAg presence in nasal swabs is not obvious and requires further investigations.

Algorithm for diagnosis of primary vasculitides

Primary vasculitides are diseases with a wide variety of anatomical, clinical, radiological, and laboratory presentations. Primary vasculitides are difficult to diagnose because of the complexity of clinical presentation, which may lead to delayed treatment and increased financial costs of workup investigations involving non-essential tests. Our objective in the present study is to create an algorithm that helps diagnosis of Primary vasculitides. The algorithm presented in this article allows fast, simple and cost-effective diagnosis of primary vasculitides using just clinical concepts and a few laboratory tests.

Relationship between serologic profile (ANCA type) and clinical features of renal involvement in ANCA-associated vasculitides

AIM

To compare the frequency, clinical features and outcomes of renal involvement in ANCA-associated vasculitides (AAV) in patients with antibodies against proteinase-3 (pr3-ANCA) and myeloperoxidase (MPO-ANCA).

MATERIALS AND METHODS

In our retrospective study we enrolled 264 patients, 94 males and 170 females, median age 53 [36; 62] years. Among them 157 were pr3-ANCA positive and 107 were MPO-ANCA positive. AAV was diagnosed according to ACR criteria and Chapel Hill consensus conference definition (2012). Median follow up was 44 [18; 93] months. We assessed baseline BVAS and VDI by the end of the follow up. Serum creatinine (sCr), estimated glomerular filtration rate (eGFR), hematuria and daily proteinuria were estimated. Diagnosis and stage of chronic kidney disease (CKD) and acute kidney injury (AKI) were established according to KDIGO guidelines (2012) and Scientific Society of Russian Nephrologists (2016).

RESULTS

Renal involvement was present in 181 (68.6%) patients, and its frequency was similar in pr3-ANCA and MPO-ANCA subgroups. Patients with MPO-ANCA developed rapidly progressive glomerulonephritis and hypertension significantly more often than patients with pr3-ANCA: 50.7% vs 35.6% (p=0.049) and 46.1% vs 29.8% (p=0.029) respectively. At disease onset, median sCr was significantly higher and eGFR was significantly lower in patients with MPO-ANCA (p&lt;0.05). 1-year and 5-year renal survival rates were similar in pr3-ANCA-positive (93.9% and 87.4% respectively) and MPO-ANCA positive patients (87.4% and 83.1% respectively). Median BVAS and VDI scores were significantly higher in pr3-ANCA subgroup. The number of patients who developed AAV relapse during 1-year follow up was also significantly higher in pr3-ANCA subgroup. The frequency of eye and ENT involvement was significantly higher in pr3-ANCA positive patients than in MPO-ANCA-positive patients.

CONCLUSION

The frequency of extrarenal manifestations, clinical features of renal involvement and relapse rate are associated with AAV serotype.

The Diagnostic and Clinical Utility of Autoantibodies in Systemic Vasculitis

Considerable progress has been made in understanding the role of autoantibodies in systemic vasculitides (SV), and consequently testing for anti-neutrophil cytoplasmic antibodies (ANCA), anti-glomerular basement membrane antibodies (anti-GBM), and anti-C1q antibodies is helpful and necessary in the diagnosis, prognosis, and monitoring of small-vessel vasculitis. ANCA-directed proteinase 3 (PR3-) or myeloperoxidase (MPO-) are sensitive and specific serologic markers for ANCA-associated vasculitides (AAV), anti-GBM antibodies are highly specific for the patients with anti-GBM antibody disease (formerly Goodpasture’s syndrome), and autoantibodies to C1q are characteristic of hypocomlementemic urticarial vasculitis syndrome (HUVS; anti-C1q vasculitis). The results of a current EUVAS study have led to changes in the established strategy for the ANCA testing in small-vessel vasculitis. The revised 2017 international consensus recommendations for ANCA detection support the primary use PR3- and MPO-ANCA immunoassays without the categorical need for additional indirect immunofluorescence (IIF). Interestingly, the presence of PR3- and MPO-ANCA have led to the differentiation of distinct disease phenotype of AAV: PR3-ANCA-associated vasculitis (PR3-AAV), MPO-ANCA-associated vasculitis (MPO-AAV), and ANCA-negative vasculitis. Further studies on the role of these autoantibodies are required to better categorize and manage appropriately the patients with small-vessel vasculitis and to develop more targeted therapy.

Clinical and histopathological prognostic factors affecting the renal outcomes in childhood ANCA-associated vasculitis

OBJECTIVE

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are very rare in childhood with an increased risk of morbidity and mortality. We aimed to evaluate renal prognostic factors in childhood AAV from the perspective of ANCA serotype, histopathological classification, and five-factor score (FFS).

METHODS

Pediatric AAV patients from 11 referral centers in Turkey had been included to the study. The demographics, clinical findings, AAV subtypes, outcomes, and FFS were evaluated retrospectively. Kidney biopsies were classified histopathologically.

RESULTS

Totally, 39 patients were enrolled in the study. Among all patients, 74.4% had renal involvement, 56.4% ear-throat-nose involvement, and 51.3% had musculoskeletal involvement. Proteinase 3 (PR3)-ANCA was positive in 48.7%, and myeloperoxidase (MPO)-ANCA was positive in 30.8%. 69.2% of patients had impaired renal function, and 28.2% had progressed to end-stage renal disease (ESRD) during the follow-up. At the time of diagnosis, FFS was ≥ 2 in 53.8%. The most common histopathologic classifications were as follows: crescentic type in 40.7% and sclerotic type in 25.9%. Gastrointestinal and renal involvement, MPO-ANCA positivity, serum creatinine levels, and impaired renal function during the follow-up were significantly higher in patients with FFS ≥ 2, compared to patients with FFS < 2. Patients with FFS ≥ 2 had more common crescentic, mixed and sclerotic histopathologic findings in biopsies. By logistic regression analysis forward method, the strongest single-risk factor among all the parameters was the initial level of creatinine in patients with ESRD, compared to the other patients (p = 0,007).

CONCLUSIONS

Evaluation of the FFS, ANCA serology, and the creatinine levels may help to predict renal prognosis.

Immunoglobulins G from patients with ANCA-associated vasculitis are atypically glycosylated in both the Fc and Fab regions and the relation to disease activity

Background

Anti-neutrophil cytoplasmic autoantibodies (ANCA) directed against myeloperoxidase (MPO) and proteinase 3 (PR3) are pathogenic in ANCA-associated vasculitis (AAV). The respective role of IgG Fc and Fab glycosylation in mediating ANCA pathogenicity is incompletely understood. Herein we investigate in detail the changes in Fc and Fab glycosylation in MPO-ANCA and Pr3-ANCA and examine the association of glycosylation aberrancies with disease activity.

Methodology

Total IgG was isolated from serum or plasma of a cohort of 30 patients with AAV (14 MPO-ANCA; 16 PR3-ANCA), and 19 healthy control subjects. Anti-MPO specific IgG was affinity-purified from plasma of an additional cohort of 18 MPO-ANCA patients undergoing plasmapheresis. We used lectin binding assays, liquid chromatography, and mass spectrometry-based methods to analyze Fc and Fab glycosylation, the degree of sialylation of Fc and Fab fragments and to determine the exact localization of N-glycans on Fc and Fab fragments.

Principal findings

IgG₁ Fc glycosylation of total IgG was significantly reduced in patients with active AAV compared to controls. Clinical remission was associated with complete glycan normalization for PR3-ANCA patients but not for MPO-ANCA patients. Fc-glycosylation of anti-MPO specific IgG was similar to total IgG purified from plasma. A major fraction of anti-MPO specific IgG harbor extensive glycosylation within the variable domain on the Fab portion.

Conclusions/Significance

Significant differences exist between MPO and PR3-ANCA regarding the changes in amounts and types of glycans on Fc fragment and the association with disease activity. These differences may contribute to significant clinical difference in the disease course observed between the two diseases.

Intravenous pulse methylprednisolone for induction of remission in severe ANCA associated Vasculitis: a multi-center retrospective cohort study

Background

Intravenous pulse methylprednisolone (MP) is commonly included in the management of severe ANCA associated vasculitis (AAV) despite limited evidence of benefit. We aimed to evaluate outcomes in patients who had, or had not received MP, along with standard therapy for remission induction in severe AAV.

Methods

We retrospectively studied 114 consecutive patients from five centres in Europe and the United States with a new diagnosis of severe AAV (creatinine > 500 μmol/L or dialysis dependency) and that received standard therapy (plasma exchange, cyclophosphamide and high-dose oral corticosteroids) for remission induction with or without pulse MP between 2000 and 2013. We evaluated survival, renal recovery, relapses, and adverse events over the first 12 months.

Results

Fifty-two patients received pulse MP in addition to standard therapy compared to 62 patients that did not. There was no difference in survival, renal recovery or relapses. Treatment with MP associated with higher risk of infection during the first 3 months (hazard ratio (HR) 2.7, 95%CI [1.4–5.3], p = 0.004) and higher incidence of diabetes (HR 6.33 [1.94–20.63], p = 0.002), after adjustment for confounding factors.

Conclusions

The results of this study suggest that addition of pulse intravenous MP to standard therapy for remission induction in severe AAV may not confer clinical benefit and may be associated with more episodes of infection and higher incidence of diabetes.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1226-0) contains supplementary material, which is available to authorized users.