Association of Pulmonary Hemorrhage, Positive Proteinase 3, and Urinary Red Blood Cell Casts With Venous Thromboembolism in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

To assess the frequency of venous thromboembolism (VTE) events in the Rituximab in Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis (RAVE) trial and identify novel potential risk factors.

METHODS

VTE events in 197 patients enrolled in the RAVE trial were analyzed. Baseline demographic and clinical characteristics were recorded, and univariate and multivariate analyses were performed to identify factors associated with VTE in ANCA-associated vasculitis (AAV).

RESULTS

VTE occurred in 16 patients (8.1%) with an overall average time to event of 1.5 months (range 1.0-2.75). In univariate analyses with calculation of hazard ratios (HRs) and 95% confidence intervals (95% CIs), heart involvement (HR 17.408 [95% CI 2.247-134.842]; P = 0.006), positive proteinase 3 (PR3)-ANCA (HR 7.731 [95% CI 1.021-58.545]; P = 0.048), pulmonary hemorrhage (HR 3.889 [95% CI 1.448-10.448]; P = 0.008), and the presence of red blood cell casts (HR 15.617 [95% CI 3.491-69.854]; P < 0.001) were associated with the onset of VTE. In multivariate models adjusted for age and sex, the significant associations between VTE events and heart involvement (HR 21.836 [95% CI 2.566-185.805]; P = 0.005), PR3-ANCA (HR 9.12 [95% CI 1.158-71.839]; P = 0.036), pulmonary hemorrhage (HR 3.91 [95% CI 1.453-10.522]; P = 0.007), and urinary red blood cell casts (HR 16.455 [95% CI 3.607-75.075]; P < 0.001) remained.

CONCLUSION

Patients diagnosed as having AAV with pulmonary hemorrhage, positive PR3-ANCA, heart involvement, and the presence of red blood cell casts are at an increased risk to develop VTE. Further studies are needed to confirm and expand these findings and to explore the mechanisms of hypercoagulability in these patients with the aim of informing potential targets for therapeutic intervention.

Disease Activity, Antineutrophil Cytoplasmic Antibody Type, and Lipid Levels in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

Patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) have an elevated risk of cardiovascular disease (CVD). This study was undertaken to develop a clearer understanding of the association between changes in disease activity and lipid levels in AAV, which may inform CVD risk stratification in this population.

METHODS

Lipid levels were assessed in stored serum samples (obtained at baseline and month 6) from the Rituximab for ANCA-Associated Vasculitis (RAVE) trial, which randomized patients to receive either rituximab or cyclophosphamide followed by azathioprine. Paired t-tests and multivariable linear regression were used to assess changes in lipid levels.

RESULTS

Of the 142 patients with serum samples available, the mean ± SD age was 52.3 ± 14.7 years, 72 (51%) were male, 95 (67%) were proteinase 3 (PR3)-ANCA positive, 72 (51%) had received a new diagnosis of AAV, and 75 (53%) were treated with rituximab. Several lipid levels increased between baseline and month 6, including total cholesterol (+12.4 mg/dl [95% confidence interval (95% CI) +7.1, +21.0]), low-density lipoprotein (+10.3 mg/dl [95% CI +6.1, +17.1]), and apolipoprotein B (+3.5 mg/dl [95% CI +1.0, +8.3]). These changes were observed among newly diagnosed and PR3-ANCA-positive patients but not among those with relapsing disease or myeloperoxidase-ANCA-positive patients. There was no difference in change in lipid levels between rituximab-treated patients and cyclophosphamide-treated patients. Changes in lipid levels correlated with changes in erythrocyte sedimentation rate but not with other inflammatory markers or glucocorticoid exposure.

CONCLUSION

Lipid levels increased during remission induction among patients with newly diagnosed AAV and those who were PR3-ANCA positive. Disease activity and ANCA type should be considered when assessing lipid profiles to stratify CVD risk in patients with AAV.

Management of IgG4-related disease

IgG4-related disease was unrecognised as a unified disease entity until this century, yet in a short period of time the disease has been appreciated to have a worldwide distribution, and its clinical, pathological, and radiological features have been described in considerable detail. The disease has strong organ predilections, and many of the clinical presentations of disease are increasingly familiar to both generalists and specialists. Early recognition of IgG4-related disease is crucial because although the disease is highly treatable, it can lead to serious organ damage and even death if undiagnosed until advanced stages. Its indolent nature often makes diagnosis challenging, and IgG4-related disease is one of the great mimickers of other diseases in the current era. Glucocorticoids are an effective treatment for IgG4-related disease, but their long-term use is problematic in a disease that frequently affects middle-aged to elderly individuals and often leads to pancreatic dysfunction. Our understanding of the pathophysiology of the disease is surprisingly advanced given the relatively recent recognition of this condition. Insights into disease pathophysiology offer the possibility of a variety of targeted treatment approaches. Looking ahead, biological therapies could profoundly alter the way in which IgG4-related disease is managed, permitting the use of specific therapies that are tailored to patients' clinical phenotypes.

The association of serum interleukin-6 levels with clinical outcomes in antineutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE

To investigate serum IL-6 (sIL-6) levels during active disease, complete remission (CR), and relapse in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), and to explore the association of changes in sIL-6 with clinical outcomes.

METHODS

sIL-6 levels were measured at baseline and longitudinally over 18 months, in 78 patients with AAV enrolled in a randomized controlled trial comparing treatment with either rituximab (RTX) or cyclophosphamide (CYC)/azathioprine (AZA). Outcome variables included baseline clinical features, ANCA specificity, disease activity (active disease versus CR), time to relapse events, B cell repopulation, and ANCA titer increases.

RESULTS

At baseline, sIL6 levels were detectable in 81% of patients; 73% (n = 57) of subjects were proteinase 3 (PR3)-ANCA positive, sIL-6 levels were higher in subjects with PR3-ANCAs and positively correlated with their levels (r_s = 0.36,p < 0.01), but not with levels of myeloperoxidase (MPO)-ANCA (r_s = -0.17,p = 0.47). Higher baseline sIL-6 levels were associated with PR3-ANCA positivity, fever, pulmonary nodules/cavities, conductive deafness, and absence of urinary red blood cell casts (p < 0.05). Baseline sIL6 levels did not predict CR at month 6 (p = 0.71), and the median sIL-6 level declined from baseline with induction therapy, regardless of CR achievement. An increase in sIL-6 during CR was a predictor for subsequent severe relapse in RTX-treated patients (hazard ratio (HR):7.24,p = 0.01), but not in CYC/AZA-treated patients (HR:0.62,p = 0.50). In contrast, a sIL-6 increase did not predict B cell repopulation or ANCA titer increase in either treatment arm (p > 0.05).

CONCLUSION

At baseline, sIL-6 concentrations correlate with PR3-ANCA titers and are associated with specific clinical manifestations of AAV. Baseline sIL6 concentrations do not predict CR at 6 months, but the increase in sIL-6 concentrations during CR is associated with subsequent severe relapse among RTX-treated patients. Further investigation into the mechanistic role of IL6 in AAV might lead to identifying this pathway as a potential therapeutic target in this disease.

B lymphocytes directly contribute to tissue fibrosis in patients with IgG4-related disease

BACKGROUND

IgG₄-related disease (IgG₄-RD) is a fibroinflammatory condition marked by rapid clinical improvement after selective depletion of B lymphocytes with rituximab. This feature suggests that B cells might participate in fibrogenesis and wound healing.

OBJECTIVE

In the present work we aimed to demonstrate that B lymphocytes contribute directly to tissue fibrosis in patients with IgG₄-RD.

METHODS

Total circulating CD19⁺ B lymphocytes, naive B cells, memory B cells, or plasmablasts from patients with IgG₄-RD were cultivated with human fibroblasts. Profibrotic soluble factors and collagen production in cocultures were assessed by using ELISAs and Luminex assays. RNA sequencing and quantitative RT-PCR were used to assess fibroblast activation in the presence of B cells, as well as induction of profibrotic pathways in B-cell subsets. Relevant profibrotic and inflammatory molecules were confirmed in vitro by using functional experiments and on IgG₄-RD tissue sections by using multicolor immunofluorescence studies.

RESULTS

B cells from patients with IgG₄-RD (1) produced the profibrotic molecule platelet-derived growth factor B and stimulated collagen production by fibroblasts; (2) expressed enzymes implicated in extracellular matrix remodeling, such as lysyl oxidase homolog 2; (3) produced the chemotactic factors CCL4, CCL5, and CCL11; and (4) induced production of these same chemokines by activated fibroblasts. Plasmablasts expressed sets of genes implicated in fibroblast activation and proliferation and therefore represent cells with intrinsic profibrotic properties.

CONCLUSION

We have demonstrated that B cells contribute directly to tissue fibrosis in patients with IgG₄-RD. These unanticipated profibrotic properties of B lymphocytes, particularly plasmablasts, might be relevant for fibrogenesis in patients with other fibroinflammatory disorders and for wound-healing processes in physiologic conditions.

An International Multispecialty Validation Study of the IgG4-Related Disease Responder Index

OBJECTIVE

IgG4-related disease (IgG4-RD) can cause fibroinflammatory lesions in nearly any organ, leading to organ dysfunction and failure. The IgG4-RD Responder Index (RI) was developed to help investigators assess the efficacy of treatment in a structured manner. The aim of this study was to validate the RI in a multinational investigation.

METHODS

The RI guides investigators through assessments of disease activity and damage in 25 domains, incorporating higher weights for disease manifestations that require urgent treatment or that worsen despite treatment. After a training exercise, investigators reviewed 12 written IgG4-RD vignettes based on real patients. Investigators calculated both an RI score as well as a physician's global assessment (PhGA) score for each vignette. In a longitudinal assessment, 3 investigators used the RI in 15 patients with newly active disease who were followed up over serial visits after treatment. We assessed interrater and intrarater reliability, precision, validity, and responsiveness.

RESULTS

The 26 physician investigators included representatives from 6 specialties and 9 countries. The interrater and intrarater reliability of the RI was strong (0.89 and 0.69, respectively). Correlations (construct validity) between the RI and PhGA were high (Spearman's r = 0.9, P < 0.0001). The RI was sensitive to change (discriminant validity). Following treatment, there was significant improvement in the RI score (mean change 10.5 [95% confidence interval (95% CI) 5.4-12], P < 0.001), which correlated with the change in the PhGA. Urgent disease and damage were captured effectively.

DISCUSSION

In this international, multispecialty study, we observed that the RI is a valid and reliable disease activity assessment tool that can be used to measure response to therapy.

Glucocorticoid Dosages and Acute-Phase Reactant Levels at Giant Cell Arteritis Flare in a Randomized Trial of Tocilizumab

Objective

This study was undertaken to evaluate glucocorticoid dosages and serologic findings in patients with giant cell arteritis (GCA) flares.

Methods

Patients with GCA were randomly assigned to receive double‐blind dosing with either subcutaneous tocilizumab (TCZ) 162 mg weekly plus 26‐week prednisone taper (TCZ‐QW + Pred‐26), every‐other‐week TCZ plus 26‐week prednisone taper (TCZ‐Q2W + Pred‐26), placebo plus 26‐week prednisone taper (PBO + Pred‐26), or placebo plus 52‐week prednisone taper (PBO + Pred‐52). Outcome measures were prednisone dosage, C‐reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR) at the time of flare.

Results

One hundred patients received TCZ‐QW + Pred‐26, 49 received TCZ‐Q2W + Pred‐26, 50 received PBO + Pred‐26, and 51 received PBO + Pred‐52. Of the 149 TCZ‐treated patients, 36 (24%) experienced flare, 23 (64%) of whom were still receiving prednisone (median dosage 2.0 mg/day). Among 101 PBO + Pred–treated patients, 59 (58%) experienced flare, 45 (76%) of whom were receiving prednisone (median dosage 5.0 mg/day). Many flares occurred while patients were taking >10 mg/day prednisone: 9 (25%) in the TCZ groups and 13 (22%) in the placebo groups. Thirty‐three flares (92%) in TCZ‐treated groups and 20 (34%) in PBO + Pred–treated groups occurred with normal CRP levels. More than half of the PBO + Pred–treated patients had elevated CRP levels without flares. Benefits of the TCZ and prednisone combination over prednisone alone for remission induction were apparent by 8 weeks.

Conclusion

Most GCA flares occurred while patients were still receiving prednisone. Acute‐phase reactant levels were not reliable indicators of flare in patients treated with TCZ plus prednisone or with prednisone alone. The addition of TCZ to prednisone facilitates earlier GCA control.

IgG4-related disease: Association with a rare gene variant expressed in cytotoxic T cells

BACKGROUND

Family screening of a 48-year-old male with recently diagnosed IgG4-related disease (IgG4-RD) revealed unanticipated elevations in plasma IgG4 in his two healthy teenaged sons.

METHODS

We performed gene sequencing, immune cell studies, HLA typing, and analyses of circulating cytotoxic CD4+ T lymphocytes and plasmablasts to seek clues to pathogenesis. DNA from a separate cohort of 99 patients with known IgG4-RD was also sequenced for the presence of genetic variants in a specific gene, FGFBP2.

RESULTS

The three share a previously unreported heterozygous single base deletion in fibroblast growth factor binding protein type 2 (FGFBP2), which causes a frameshift in the coding sequence. The FGFBP2 protein is secreted by cytotoxic T-lymphocytes and binds fibroblast growth factor. The variant sequence in the FGFBP2 protein is predicted to form a disordered random coil rather than a helical-turn-helix structure, unable to adopt a stable conformation. The proband and the two sons had 5-10-fold higher numbers of circulating cytotoxic CD4 + T cells and plasmablasts compared to matched controls. The three members also share a homozygous missense common variant in FGFBP2 found in heterozygous form in ~40% of the population. This common variant was found in 73% of an independent, well characterized IgG4-RD cohort, showing enrichment in idiopathic IgG4-RD.

CONCLUSIONS

The presence of a shared deleterious variant and homozygous common variant in FGFBP2 in the proband and sons strongly implicates this cytotoxic T cell product in the pathophysiology of IgG4-RD. The high prevalence of a common FGFBP2 variant in sporadic IgG4-RD supports the likelihood of participation in disease.

Phospholipase A2 receptor-associated membranous nephropathy in a patient with IgG4-related disease: A case report

RATIONALE

IgG4-related disease (IgG4-RD) is a multiorgan disease of unestablished prevalence that is characterized histopathologically by a dense lymphoplasmacytic infiltrate enriched with IgG4-expressing plasma cells and associated with storiform fibrosis. Tubulointerstitial nephritis (TIN) is the most common renal manifestation of IgG4-RD, but membranous nephropathy (MN) has also been described and often occurs in the context of concurrent TIN. Patients with IgG4-related MN have been characteristically negative for autoantibodies to the phospholipase A2 receptor (PLA2R).

PATIENT CONCERNS

A 45-year-old man presented with abdominal pain and lower extremity edema.

DIAGNOSIS

Histopathological evaluation of pancreas and liver biopsies established a diagnosis of IgG4-RD. Renal biopsy confirmed a diagnosis of PLA2R-associated MN without evidence of concurrent TIN.

INTERVENTIONS

The patient was treated with rituximab, a short course of low-dose, oral cyclophosphamide, and a rapid glucocorticoid taper.

OUTCOMES

The patient achieved remission of MN after 8 months of therapy and maintained remission of IgG4-RD.

LESSONS

PLA2R-associated MN may be a rare manifestation of IgG4-RD. Systematic evaluation of larger cohorts of IgG4-RD patients for the presence of PLA2R autoantibodies and the investigation of PLA2R-associated MN cohorts for evidence of IgG4-RD would facilitate the understanding of the nature of the relationship between these observations.

Health-related quality of life in patients with giant cell arteritis treated with tocilizumab in a phase 3 randomised controlled trial

Background

Patients with giant cell arteritis (GCA) treated with tocilizumab (TCZ) every week or every other week and prednisone tapering achieved superior rates of sustained remission to patients treated with placebo and prednisone tapering in a randomised controlled trial. Health-related quality of life (HRQOL) in patients from this trial is now reported.

Methods

Exploratory analyses of SF-36 PCS and MCS and domain scores, PtGA and FACIT-Fatigue were performed in patients treated with weekly subcutaneous TCZ 162 mg plus 26-week prednisone taper (TCZ-QW + Pred-26) or placebo plus 26-week or 52-week prednisone tapers (PBO + Pred-26 or PBO + Pred-52). These analyses were performed on responder and non-responder patients, including those who achieved the primary outcome and those who experienced flare and received escape prednisone doses.

Results

Baseline SF-36 PCS, MCS and domain scores were low, indicating impaired HRQOL related to GCA. At week 52, least squares mean (LSM) changes in PCS scores improved with TCZ-QW + Pred-26 but worsened in both PBO + Pred groups (p <  0.001). LSM changes in MCS scores increased with TCZ-QW + Pred-26 versus PBO + Pred-52 (p < 0.001). Treatment with TCZ-QW + Pred-26 resulted in significantly greater improvement in four of eight SF-36 domains compared with PBO + Pred-26 and six of eight domains compared with PBO + Pred-52 (p < 0.01). Improvement with TCZ-QW + Pred-26 met or exceeded minimum clinically important differences (MCID) in all eight domains compared with five domains with PBO + Pred-26 and none with PBO + Pred-52. Domain scores in the TCZ-QW + Pred-26 group at week 52 met or exceeded age- and gender-matched normative values (A/G norms). LSM changes from baseline in FACIT-Fatigue scores increased significantly with TCZ-QW + Pred-26, exceeding MCID and A/G norms (p < 0.001).

Conclusions

Patients with GCA receiving TCZ-QW + Pred-26 reported statistically significant and clinically meaningful improvement in SF-36 and FACIT-Fatigue scores compared with those receiving prednisone only. Improvements in the TCZ-QW + Pred-26 group led to recovery of HRQOL to levels at least comparable to those of A/G-matched normative values at week 52 and exceeded normative values in five of eight domains.

Trial registration

ClinicalTrials.gov, NCT01791153. Date of registration: February 13, 2013.

Clinical features and mechanistic insights regarding IgG4-related dacryoadenitis and sialoadenitis: a review

Immunoglobulin G4-related disease (IgG4-RD), recognized only recently as a single diagnostic entity, is a chronic inflammatory condition of unknown etiology. The diagnosis of IgG4-RD relies heavily on histopathological analysis and the correlation of histology findings with clinical, serological, and radiological data. CD4⁺ T and B cells, including IgG4-expressing plasmablasts, constitute the major inflammatory cell populations in IgG4-RD and are believed to cause organ damage and tissue fibrosis. Patients with IgG4-RD, who have active, untreated disease, exhibit marked expansion of IgG4-secreting plasmablasts in the blood. Important mechanistic insights correlated with the pathogenesis of IgG4-RD have been disclosed in recent years through the application of novel molecular biology approaches, including next-generation and single-cell RNA sequencing. Exploration of the interactions between these CD4⁺ T cells and cells of the B lymphocyte lineage is critical to understanding the pathophysiology of IgG4-RD. The establishment of pathogenic T cell clones and the identification of antigens specific to these clones constitute the first steps in determining the pathogenesis of this disease. This review focuses on clinical features and mechanistic insights regarding IgG4-related dacryoadenitis and sialoadenitis, from a perspective suitable for oral and maxillofacial surgeons.

IgG4-related disease of the central and peripheral nervous systems

IgG4-related disease can involve nearly any organ system, including the central and peripheral nervous systems. The pathology findings are consistent from organ to organ, but careful clinicopathological correlation is necessary to establish the diagnosis. Many non-neurological and neurological inflammatory conditions, previously regarded as idiopathic in nature, are now recognised to fall within the spectrum of IgG4-related disease. The condition is highly treatable, but probably remains substantially under-recognised. In this Review, we offer an important and timely update on the current and emerging aspects of this neurological disease. Following a short overview of IgG4-related disease, we describe the current understanding of neurological findings, pathophysiology, approaches to diagnosis, and treatment of IgG4-related disease affecting the central and peripheral nervous systems.

Clinical phenotypes of IgG4-related disease: an analysis of two international cross-sectional cohorts

OBJECTIVE

IgG4-related disease (IgG4-RD) is a heterogeneous, multiorgan condition of unclear aetiology that can cause organ failure. Difficulty recognising IgG4-RD contributes to diagnostic delays. We sought to identify key IgG4-RD phenotypes.

METHODS

We used two cross-sectional studies assembled by an international, multispecialty network of IgG4-RD specialists who submitted 765 cases to derive and replicate phenotypic groups. Phenotype groups of disease manifestations and key covariate distributions across the identified groups were measured using latent class analysis.

RESULTS

In the derivation cohort (n=493), we identified four groups with distinct manifestations: Group 1 (31%), Pancreato-Hepato-Biliary disease; Group 2 (24%), Retroperitoneal Fibrosis and/or Aortitis; Group 3 (24%), Head and Neck-Limited disease and Group 4 (22%), classic Mikulicz syndrome with systemic involvement. We replicated the identification of four phenotype groups in the replication cohort. Compared with cases in Groups 1, 2 and 4, respectively, cases in Group 3 were more likely to be female (OR 11.60 (95% CI 5.39 to 24.98), 10.35 (95% CI 4.63 to 23.15) and 9.24 (95% CI 3.53 to 24.20)) and Asian (OR 6.68 (95% CI 2.82 to 15.79), 7.43 (95% CI 2.97 to 18.56) and 6.27 (95% CI 2.27 to 17.29)). Cases in Group 4 had a higher median serum IgG4 concentration (1170 mg/dL) compared with groups 1-3 (316, 178 and 445 mg/dL, respectively, p<0.001).

CONCLUSION

We identified four distinctive IgG4-RD phenotypes according to organ involvement. Being Asian or female may predispose individuals to head and neck-limited disease. These phenotypes serve as a framework for identifying IgG4-RD and studying its aetiology and optimal treatment.

Role of Macrophage Migration Inhibitory Factor in Granulomatosis With Polyangiitis

OBJECTIVE

To examine the association between macrophage migration inhibitory factor (MIF) promoter polymorphisms and granulomatosis with polyangiitis (GPA) in human subjects, and to assess the role of MIF in a murine model of granulomatous vasculitis.

METHODS

The human study involved 1,077 patients with GPA and healthy controls whose serum was genotyped by capillary electrophoresis for the MIF -794 CATT_5-8 promoter microsatellite (rs5844572). MIF promoter, CATT-length-dependent gene expression in response to β-glucan was assessed by gene reporter assays. In mouse studies, granulomatous disease was induced by injection of Candida albicans β-glucan into wild-type (WT) or Mif-knockout (Mif-KO) C57BL/6 mice and C57BL/6 mice transgenically overexpressing Mif in lung epithelium (Mif lung-Tg2.1). Mice were treated with a neutralizing anti-MIF antibody and analyzed for the density of pulmonary granulomas, expression of inflammatory chemokines, and frequency of mortality.

RESULTS

The percentage of human subjects carrying >5 CATT repeats in each MIF allele (high genotypic MIF expressers) was 60.2% among patients with GPA and 53.9% among healthy controls (adjusted P = 0.049). In response to granulomatous stimulation, human MIF gene expression increased proportionally with CATT length. Mif lung-Tg2.1 mice exhibited more pulmonary granulomas than WT mice, which in turn showed more granulomas than Mif-KO mice. A significantly higher percentage of Mif lung-Tg2.1 mice, compared to Mif-KO or WT mice, died when injected with Candida albicans β-glucan, and treatment of these mice with an anti-MIF monoclonal antibody protected against a lethal outcome. Levels of MIF-dependent neutrophil/macrophage chemokines were elevated in the bronchoalveolar lavage fluid or plasma of Mif lung-Tg2.1 mice.

CONCLUSION

Patients with GPA have an increased frequency of high MIF expression CATT alleles. Higher Mif expression increases the incidence of mortality and pulmonary granulomas in Mif lung-Tg2.1 mice, while anti-MIF treatment protects these mice against death. Blockade of MIF in high genotypic MIF expressers may therefore offer a selective pharmacologic therapy for GPA.

Rituximab for idiopathic and IgG4-related retroperitoneal fibrosis

Retroperitoneal fibrosis (RPF) refers to a fibro-inflammatory lesion in the retroperitoneum, often anterolateral to the aorta. Most cases are due to IgG4-related disease (IgG4-RD) or are idiopathic. RPF can lead to severe morbidity. Treatment strategies remain poorly-defined. We evaluated the efficacy and safety of rituximab (RTX) for idiopathic or IgG4-related RPF.We retrospectively reviewed the records of patients who had RPF treated with RTX. Treatment response was determined by assessing changes in both clinical features, including symptoms and laboratory measurements, as well as in the radiographic dimensions of the lesion.Twenty-six patients with IgG4-related (n = 19) or idiopathic RPF (n = 7) were identified. Patients without histopathological evidence of IgG4-RD on either retroperitoneal biopsies or sampling of extra-retroperitoneal organs were considered to have idiopathic RPF. Of the 26 patients, 19 (73%) received RTX without additional glucocorticoids. All 19 patients who presented with pain reported symptomatic improvement following RTX. Among 25 patients with follow-up imaging, 22 (88%) had radiologic improvement. Among 10 patients with ureteral stents and/or percutaneous nephrostomy tubes, 4 (40%) underwent successful stent or tube removal. Responses to treatment were similar among those treated with RTX monotherapy and those treated with RTX and glucocorticoids. RTX was generally well tolerated, but 3 (12%) patients experienced severe infections.In this study, RTX for RPF led to resolution of symptoms in all patients and radiographic improvement in the majority. Prospective studies of RTX for RPF are indicated.

Improving Mortality in End-Stage Renal Disease Due to Granulomatosis With Polyangiitis (Wegener's) From 1995 to 2014: Data From the United States Renal Data System

OBJECTIVE

To examine temporal trends in mortality rates in a large nationwide cohort of patients with end-stage renal disease (ESRD) due to granulomatosis with polyangiitis (Wegener's) (GPA-ESRD).

METHODS

We identified cases of GPA-ESRD reported in the US Renal Data System between 1995 and 2014, using coding by nephrologists for the cause of ESRD. The cohort was divided into four 5-year subcohorts based on the year of onset of ESRD (1995-1999, 2000-2004, 2005-2009, and 2010-2014) to assess trends in mortality rates and hazard ratios (HRs) for overall death and cause-specific death, adjusting for potential confounders.

RESULTS

Between 1995 and 2014, there were 5,929 incident cases of GPA-ESRD. The mortality rate (incidence per 100 patient-years) declined from 19.0 in 1995-1999 to 15.3 in 2010-2014 (P for trend = 0.01). The multivariable-adjusted HR for mortality in the 2010-2014 cohort was 0.77 (95% confidence interval [95% CI] 0.66-0.90) (P for trend < 0.001 versus the 1995-1999 cohort). The corresponding cause-specific HRs for mortality, after accounting for competing risk, were 0.61 (95% CI 0.47-0.80) for CVD-related death and 0.42 (95% CI 0.28-0.63) for death due to infection (P for trend < 0.001).

CONCLUSION

In this study of nearly all patients in whom GPA-ESRD developed in the US over 2 decades, we observed significant improvements in mortality among GPA-ESRD patients. The number of cause-specific deaths due to CVD and the number due to infections declined significantly during the study period. These findings are encouraging and likely reflect improved management of both GPA and ESRD.

Why do temporal arteries go wrong? Principles and pearls from a clinician and a pathologist

Early diagnosis and treatment of GCA is essential to prevent complications of the disease, including permanent vision loss. Temporal artery biopsy has been intrinsically linked with the diagnosis of GCA for several decades. A negative predictive value of > 90% has been reported for temporal artery biopsy; however, a negative result does not reliably indicate the absence of GCA because inflammation of the temporal artery is not always evident because of segmental involvement or other reasons. This is demonstrated by a case study of a patient hospitalized following acute vision loss to the right eye whose glucocorticoid treatment was suspended after temporal artery biopsy revealed no evidence of GCA. The patient subsequently lost sight in the left eye 6 weeks after stopping glucocorticoid therapy. The specificity of temporal artery biopsy for the diagnosis of GCA is variable and influenced by many factors, including length of biopsy specimens, vasculitis in vessels other than the temporal artery (ophthalmic, retinal and posterior ciliary vessels), unilateral versus bilateral biopsy, expertise of the surgeon, interpretation of histology, effects of treatment and confounding factors such as atherosclerosis or other non-GCA diseases that can affect the temporal artery. Considering the limitations of temporal artery biopsy, collaboration and education between the clinician, the pathologist and the patient, taking into account a thorough examination of patient history, recognizing signs and symptoms, and potentially involving newer imaging studies with trained technicians and physicians, are essential in confirming or eliminating diagnosis of GCA.

A CD8α- Subset of CD4+SLAMF7+ Cytotoxic T Cells Is Expanded in Patients With IgG4-Related Disease and Decreases Following Glucocorticoid Treatment

OBJECTIVE

An unconventional population of CD4+ signaling lymphocytic activation molecule family member 7-positive (SLAMF7+) cytotoxic effector memory T (TEM ) cells (CD4+ cytotoxic T lymphocytes [CTLs]) has been linked causally to IgG4-related disease (IgG4-RD). Glucocorticoids represent the first-line therapeutic approach in patients with IgG4-RD, but their mechanism of action in this specific condition remains unknown. We undertook this study to determine the impact of glucocorticoids on CD4+ CTLs in IgG4-RD.

METHODS

Expression of CD8α, granzyme A, perforin, and SLAMF7 within the effector memory compartment of CD45RO+ (TEM ) and CD45RA+ effector memory T (TEMRA ) CD4+ cells was quantified by flow cytometry in 18 patients with active IgG4-RD, both at baseline and after 6 months of glucocorticoid treatment. Eighteen healthy subjects were studied as controls. Next-generation sequencing of the T cell receptor α- and β-chain gene was performed on circulating CD4+ CTLs from patients with IgG4-RD before and after treatment and in affected tissues.

RESULTS

Circulating CD4+ TEM and TEMRA cells were not expanded in IgG4-RD patients compared to healthy controls. CD4+SLAMF7+ TEM cells (but not TEMRA cells) were significantly increased among IgG4-RD patients. Within CD4+SLAMF7+ TEM cells, CD8α- cells but not CD8αlow cells were elevated in IgG4-RD patients. The same dominant clones of CD8α-CD4+SLAMF7+ TEM cells found in peripheral blood were also identified in affected tissue. CD8α- and CD8αlow CD4+SLAMF7+ TEM cells both expressed cytolytic molecules. Clonally expanded CD8α- but not CD8αlow CD4+SLAMF7+ TEM cells decreased following glucocorticoid-induced disease remission.

CONCLUSION

A subset of CD8α-CD4+SLAMF7+ cytotoxic TEM cells is oligoclonally expanded in patients with active IgG4-RD. This TEM cell population contracts following glucocorticoid-induced remission. Further characterization of this cell population may provide prognostic information and targets for therapeutic intervention.

Improved survival with renal transplantation for end-stage renal disease due to granulomatosis with polyangiitis: data from the United States Renal Data System

BACKGROUND

Renal transplantation is the optimal treatment for selected patients with end-stage renal disease (ESRD). However, the survival benefit of renal transplantation among patients with ESRD attributed to granulomatosis with polyangiitis (GPA) is unknown.

METHODS

We identified patients from the United States Renal Data System with ESRD due to GPA (ESRD-GPA) between 1995 and 2014. We restricted our analysis to waitlisted subjects to evaluate the impact of transplantation on mortality. We followed patients until death or the end of follow-up. We compared the relative risk (RR) of all-cause and cause-specific mortality in patients who received a transplant versus non-transplanted patients using a pooled logistic regression model with transplantation as a time-varying exposure.

RESULTS

During the study period, 1525 patients were waitlisted and 946 received a renal transplant. Receiving a renal transplant was associated with a 70% reduction in the risk of all-cause mortality in multivariable-adjusted analyses (RR=0.30, 95% CI 0.25 to 0.37), largely attributed to a 90% reduction in the risk of death due to cardiovascular disease (CVD) (RR=0.10, 95% 0.06-0.16).

DISCUSSION

Renal transplantation is associated with a significant decrease in all-cause mortality among patients with ESRD attributed to GPA, largely due to a decrease in the risk of death to CVD. Prompt referral for transplantation is critical to optimise outcomes for this patient population.

Brief Report: Circulating Cytokine Profiles and Antineutrophil Cytoplasmic Antibody Specificity in Patients With Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

To evaluate circulating cytokine profiles in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), classified by antineutrophil cytoplasmic antibody (ANCA) specificity (proteinase 3 ANCA [PR3-ANCA] versus myeloperoxidase ANCA [MPO-ANCA]) or by clinical diagnosis (granulomatosis with polyangiitis [GPA] versus microscopic polyangiitis [MPA]).

METHODS

A panel of 29 cytokines was tested in 186 patients with active AAV at inclusion into the Rituximab in AAV trial. Cytokine concentrations were compared between groups within each classification system. Multivariable analyses adjusted for age, sex, and renal insufficiency were performed, with each biomarker as a dependent variable and ANCA specificity and clinical diagnosis as explanatory variables of interest.

RESULTS

Levels of 9 circulating cytokines (interleukin-6 [IL-6], granulocyte-macrophage colony-stimulating factor [GM-CSF], IL-15, IL-18, CXCL8/IL-8, CCL-17/thymus and activation-regulated chemokine [TARC], IL-18 binding protein [IL-18 BP], soluble IL-2 receptor α [sIL-2Rα], and nerve growth factor β [NGFβ]) were significantly higher in PR3-AAV than MPO-AAV, 4 cytokines (sIL6R, soluble tumor necrosis factor receptor type II [sTNFRII], neutrophil gelatinase-associated lipocalin [NGAL], and soluble intercellular adhesion molecule 1 [sICAM-1]) were higher in MPO-AAV than in PR3-AAV, 6 cytokines (IL-6, GM-CSF, IL-15, IL-18, sIL-2Rα, and NGFβ) were higher in GPA than in MPA, and 3 cytokines (osteopontin, sTNFRII, and NGAL) were higher in MPA than in GPA (all P < 0.05). For nearly all cytokines, the difference between PR3-AAV and MPO-AAV was larger than that between GPA and MPA. The multivariate analysis showed that 8 cytokines (IL-15, IL-8, IL-18 BP, NGF-β, sICAM-1, TARC, osteopontin, and kidney injury molecule 1 (P < 0.05) distinguished patients with AAV better (lower P values and larger effect sizes) when grouped by ANCA specificity than by clinical diagnosis.

CONCLUSION

Distinct cytokine profiles were identified for PR3-AAV versus MPO-AAV and for GPA versus MPA. Differences in these circulating immune mediators are more strongly associated with ANCA specificity than with clinical diagnosis, suggesting that heterogeneity in the AAV subtypes extends beyond clinical phenotypes.

The expansion in lymphoid organs of IL-4+ BATF+ T follicular helper cells is linked to IgG4 class switching in vivo

Distinct T follicular helper (T_FH) subsets that influence specific class-switching events are assumed to exist, but the accumulation of isotype-specific T_FH subsets in secondary lymphoid organs (SLOs) and tertiary lymphoid organs has not been hitherto demonstrated. IL-4-expressing T_FH cells are surprisingly sparse in human SLOs. In contrast, in IgG4-related disease (IgG4-RD), a disorder characterized by polarized Ig class switching, most T_FH cells in tertiary and SLOs make IL-4. Human IL-4⁺ T_FH cells do not express GATA-3 but express nuclear BATF, and the transcriptomes of IL-4-secreting T_FH cells differ from both PD1^hi T_FH cells that do not secrete IL-4 and IL-4-secreting non-T_FH cells. Unlike IgG4-RD, IL-4⁺ T_FH cells are rarely found in tertiary lymphoid organs in Sjögren's syndrome, a disorder in which IgG4 is not elevated. The proportion of CD4⁺IL-4⁺BATF⁺ T cells and CD4⁺IL-4⁺CXCR5⁺ T cells in IgG4-RD tissues correlates tightly with tissue IgG4 plasma cell numbers and plasma IgG4 levels in patients but not with the total plasma levels of other isotypes. These data describe a disease-related T_FH subpopulation in human tertiary lymphoid organs and SLOs that is linked to IgG4 class switching.

Pharmacokinetics of rituximab and clinical outcomes in patients with anti-neutrophil cytoplasmic antibody associated vasculitis

Objectives

To study the determinants of the pharmacokinetics (PK) of rituximab (RTX) in patients with ANCA-associated vasculitis (AAV) and its association with clinical outcomes.

Methods

This study included data from 89 patients from the RTX in AAV trial who received the full dose of RTX (four weekly infusions of 375 mg/m2). RTX was quantified at weeks 2, 4, 8, 16 and 24, and summarized by computing the trapezoidal area under the curve. We explored potential determinants of the PK-RTX, and analysed its association with clinical outcomes: achievement of remission at 6 months, duration of B-cell depletion and time to relapse in patients who achieved complete remission.

Results

RTX serum levels were significantly lower in males and in newly diagnosed patients, and negatively correlated with body surface area, baseline B-cell count and degree of disease activity. In multivariate analyses, the main determinants of PK-RTX were sex and new diagnosis. Patients reaching complete remission at month 6 had similar RTX levels compared with patients who did not reach complete remission. Patients with higher RTX levels generally experienced longer B-cell depletion than patients with lower levels, but RTX levels at the different time points and area under the curve were not associated with time to relapse.

Conclusion

Despite the body-surface-area-based dosing protocol, PK-RTX is highly variable among patients with AAV, its main determinants being sex and newly diagnosed disease. We did not observe any relevant association between PK-RTX and clinical outcomes. The monitoring of serum RTX levels does not seem clinically useful in AAV.

The Utility of Urinalysis in Determining the Risk of Renal Relapse in ANCA-Associated Vasculitis

BACKGROUND AND OBJECTIVES

The significance of persistent hematuria or proteinuria in patients with ANCA-associated vasculitis who are otherwise in clinical remission is unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A post hoc analysis was conducted using participants enrolled in two randomized, placebo-controlled clinical trials who had active GN due to ANCA-associated vasculitis, had positive ANCA, and achieved remission by month 6. Dipstick and microscopic urinalyses were performed at each visit. Persistent hematuria or proteinuria for at least 6 months and the cumulative duration of hematuria were examined. Renal relapse was defined as new or worsening red blood cell casts and/or worsening kidney function according to the Birmingham Vasculitis Activity Score for Granulomatosis with Polyangiitis.

RESULTS

There were 149 patients included in this study: 42% had persistent hematuria, and 43% had persistent proteinuria beyond 6 months. Persistent hematuria was associated with a significantly higher risk of relapse, even after adjusting for potential confounders (subdistribution hazard ratio, 3.99; 95% confidence interval, 1.20 to 13.25; P=0.02); persistent proteinuria was not associated with renal relapse (subdistribution hazard ratio, 1.44; 95% confidence interval, 0.47 to 4.42; P=0.53). Furthermore, greater cumulative duration of hematuria was significantly associated with a higher risk of renal relapse (adjusted subdistribution hazard ratio, 1.08 per each month; 95% confidence interval, 1.03 to 1.12; P<0.01). The median time to renal relapse was 22 months.

CONCLUSIONS

In patients with ANCA-associated vasculitis and kidney involvement who achieve remission after induction therapy, the presence of persistent hematuria, but not proteinuria, is a significant predictor of future renal relapse.

Clonally expanded cytotoxic CD4+ T cells and the pathogenesis of IgG4-related disease

IgG4-related disease (IgG4-RD) is a systemic condition of unknown cause characterized by highly fibrotic lesions, with dense lymphoplasmacytic infiltrates containing a preponderance of IgG4-expressing plasma cells. CD4⁺ T cells and B cells constitute the major inflammatory cell populations in IgG4-RD lesions. IgG4-RD patients with active, untreated disease show a marked expansion of plasmablasts in the circulation. Although the therapeutic depletion of B cells suggests a role for these cells in the disease, a direct role for B cells or IgG4 in the pathogenesis of IgG4-RD is yet to be demonstrated. Among the CD4⁺ T-cell subsets, Th2 cells were initially thought to contribute to IgG4-RD pathogenesis, but many previous studies were confounded by the concomitant history of allergic diseases in the patients studied and the failure to use multi-color staining to definitively identify T-cell subsets in tissue samples. More recently, using an unbiased approach to characterize CD4⁺ T-cell subsets in patients with IgG4-RD - based on their clonal expansion and ability to infiltrate affected tissue sites - CD4⁺ CTLs have been identified as the major CD4⁺ T-cell subset in disease lesions as well as in the circulation. CD4⁺ CTLs in affected tissues secrete pro-fibrotic cytokines including IL-1β, TGF-β1, and IFN-γ as well as cytolytic molecules such as perforin and granzymes A and B. In this review, we examine possible mechanisms by which activated B cells and plasmablasts may collaborate with the expanded CD4⁺ CTLs in driving the fibrotic pathology of the disease and describe the lacunae in the field and in our understanding of IgG4-RD pathogenesis.

Interstitial Immunostaining and Renal Outcomes in Antineutrophil Cytoplasmic Antibody-Associated Glomerulonephritis

BACKGROUND

Immunopathologic features predict renal function at baseline and follow-up in antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (GN). The interstitial infiltrate consists predominantly of T lymphocytes, but their pathophysiologic significance is unclear, especially in light of the success of B-cell-directed therapy.

METHODS

Renal biopsies from 33 patients treated with cyclophosphamide (CYC; n = 17) or rituximab (RTX; n = 16) in the RTX in ANCA-associated vasculitis (RAVE) trial were classified according to the new ANCA GN classification. T- and B-cell infiltration in the interstitium was assessed by immunostaining for CD3 and CD20. Correlations of clinical and histologic parameters with renal function at set time points were examined.

RESULTS

The mean (SD) baseline estimated glomerular filtration rate was 36 (20) mL/min/1.73 m2. ANCA GN class distribution was 46% focal, 33% mixed, 12% sclerotic and 9% crescentic. The interstitial infiltrate consisted of >50% CD3 positive cells in 69% of biopsies, but >50% CD20 positive cells only in 8% of biopsies. In a multiple linear regression model, only baseline glomerular filtration rate (GFR) correlated with GFR at 6, 12, and 18 months. Interstitial B- and T-cell infiltrates had no significant impact on long-term prognosis, independent of the treatment limb. A differential effect was noted only at 6 months, where a dense CD3 positive infiltrate predicted lower GFR in the RTX group and a CD20 positive infiltrate predicted higher GFR in the CYC group.

CONCLUSIONS

In ANCA-associated GN, the interstitial infiltrate contains mainly T lymphocytes. However, it is neither reflecting baseline renal function nor predictive of response to treatment, regardless of the immunosuppression regimen employed.

Atypical IgG4+ Plasmacytic Proliferations and Lymphomas: Characterization of 11 Cases

OBJECTIVES

To report the clinicopathologic features of monotypic immunoglobulin G4+ (IgG4+) lymphoid and plasmacytic proliferations.

METHODS

Cases were identified from the pathology files. Pathology and clinical materials were reviewed.

RESULTS

Eleven cases of monotypic IgG4+ proliferations were identified at nodal, orbital, or salivary sites. Six cases (three men, three women; age, 57-94 years) met criteria for lymphoma or plasma cell neoplasia. Most contained frequent Mott cells. Five cases (three men, two women; age, 40-80 years) had restricted proliferations of atypical/monotypic IgG4+ plasma cells in a background of reactive lymphoid hyperplasia or inflammation.

CONCLUSIONS

Monotypic IgG4+ proliferations include lymphomas, plasmacytic neoplasms, and a previously uncharacterized group of proliferations not meeting criteria for conventional hematolymphoid neoplasia. Distinct features included prominent Mott cells and/or monotypic plasma cells within follicles. The proliferations were infrequently associated with IgG4-related disease (IgG4-RD). Our findings raise questions regarding the relationship between clonal IgG4+ proliferations, reactive/inflammatory processes, and IgG4-RD.

Effect of Disease Activity, Glucocorticoid Exposure, and Rituximab on Body Composition During Induction Treatment of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

We investigated the relationships between glucocorticoid use, disease activity, and changes in body mass index (BMI) in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV).

METHODS

We analyzed AAV patients enrolled in the Rituximab in AAV trial. Glucocorticoid use, BMI, and disease activity were measured regularly during the trial period. We performed mixed-effects regressions to examine the associations of time-dependent cumulative average glucocorticoid use and disease activity with changes in BMI over time, while adjusting for potential confounders.

RESULTS

The mean ± SD baseline BMI of the 197 patients enrolled was 28.8 ± 6.3 kg/m² . Patients with newly diagnosed AAV tended to have a lower mean ± SD BMI than those with relapsing disease (28.0 ± 5.7 kg/m² versus 29.6 ± 6.8 kg/m² ) and higher disease activity (mean ± SD Birmingham Vasculitis Activity Score for Wegener's Granulomatosis 8.7 ± 3.3 versus 7.4 ± 2.7). The most significant change in BMI occurred during the first 6 months of the trial (mean ± SD increase of 1.1 ± 2.2 kg/m² ; P < 0.0001). Disease activity improvement, glucocorticoid exposure, and randomization to rituximab were each independently associated with an increase in BMI (P < 0.001 for all analyses).

CONCLUSION

Our findings suggest that changes in BMI, as well as glucocorticoid exposure, are independently associated with improvements in disease activity in AAV. Rituximab may also have effects on BMI independent of its impact on disease activity.

Trial of Tocilizumab in Giant-Cell Arteritis

BACKGROUND

Giant-cell arteritis commonly relapses when glucocorticoids are tapered, and the prolonged use of glucocorticoids is associated with side effects. The effect of the interleukin-6 receptor alpha inhibitor tocilizumab on the rates of relapse during glucocorticoid tapering was studied in patients with giant-cell arteritis.

METHODS

In this 1-year trial, we randomly assigned 251 patients, in a 2:1:1:1 ratio, to receive subcutaneous tocilizumab (at a dose of 162 mg) weekly or every other week, combined with a 26-week prednisone taper, or placebo combined with a prednisone taper over a period of either 26 weeks or 52 weeks. The primary outcome was the rate of sustained glucocorticoid-free remission at week 52 in each tocilizumab group as compared with the rate in the placebo group that underwent the 26-week prednisone taper. The key secondary outcome was the rate of remission in each tocilizumab group as compared with the placebo group that underwent the 52-week prednisone taper. Dosing of prednisone and safety were also assessed.

RESULTS

Sustained remission at week 52 occurred in 56% of the patients treated with tocilizumab weekly and in 53% of those treated with tocilizumab every other week, as compared with 14% of those in the placebo group that underwent the 26-week prednisone taper and 18% of those in the placebo group that underwent the 52-week prednisone taper (P<0.001 for the comparisons of either active treatment with placebo). The cumulative median prednisone dose over the 52-week period was 1862 mg in each tocilizumab group, as compared with 3296 mg in the placebo group that underwent the 26-week taper (P<0.001 for both comparisons) and 3818 mg in the placebo group that underwent the 52-week taper (P<0.001 for both comparisons). Serious adverse events occurred in 15% of the patients in the group that received tocilizumab weekly, 14% of those in the group that received tocilizumab every other week, 22% of those in the placebo group that underwent the 26-week taper, and 25% of those in the placebo group that underwent the 52-week taper. Anterior ischemic optic neuropathy developed in one patient in the group that received tocilizumab every other week.

CONCLUSIONS

Tocilizumab, received weekly or every other week, combined with a 26-week prednisone taper was superior to either 26-week or 52-week prednisone tapering plus placebo with regard to sustained glucocorticoid-free remission in patients with giant-cell arteritis. Longer follow-up is necessary to determine the durability of remission and safety of tocilizumab. (Funded by F. Hoffmann-La Roche; ClinicalTrials.gov number, NCT01791153 .).

Myeloperoxidase-Antineutrophil Cytoplasmic Antibody (ANCA)-Positive and ANCA-Negative Patients With Granulomatosis With Polyangiitis (Wegener's): Distinct Patient Subsets

OBJECTIVE

To examine the relationship of antineutrophil cytoplasmic antibody (ANCA) type and ANCA-associated vasculitis (AAV) diagnosis with demographic features, disease manifestations, and clinical outcomes. We focused on patients who account for the differences between ANCA type and disease type classifications: anti-myeloperoxidase (MPO)-ANCA-positive and ANCA-negative patients with granulomatosis with polyangiitis (Wegener's) (GPA).

METHODS

We performed a pooled analysis of the Wegener's Granulomatosis Etanercept Trial and the Rituximab in ANCA-Associated Vasculitis trial comparing patients with MPO-ANCA-positive GPA and patients with ANCA-negative GPA to patients with proteinase 3 (PR3)-ANCA-positive GPA and patients with MPO-ANCA-positive microscopic polyangiitis (MPA).

RESULTS

Of the 365 patients analyzed, 273 (75%) had PR3-ANCA-positive GPA, 33 (9%) had MPO-ANCA-positive GPA, 15 (4%) had ANCA-negative GPA, and 44 (12%) had MPO-ANCA-positive MPA. MPO-ANCA-positive GPA patients were younger at diagnosis compared to MPO-ANCA-positive MPA patients (53 versus 61 years; P = 0.02). Their disease manifestations and rates of relapse were similar to those of PR3-ANCA-positive GPA patients. Relapse was more frequent in MPO-ANCA-positive GPA patients than in patients with MPO-ANCA-positive MPA at trial entry as well as at 12 and 18 months. ANCA-negative patients with GPA had lower Birmingham Vasculitis Activity Score for Wegener's Granulomatosis scores at trial entry than PR3-ANCA-positive patients with GPA (4.5 versus 7.7; P < 0.01), primarily because of a lower prevalence of renal involvement.

CONCLUSION

We were unable to demonstrate important clinical differences between MPO-ANCA-positive and PR3-ANCA-positive patients with GPA. The risk of relapse was associated more closely with disease type than with ANCA type in this patient cohort. These findings deserve consideration in the assessment of relapse risk in patients with AAV.

Association of Serum Calprotectin (S100A8/A9) Level With Disease Relapse in Proteinase 3-Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

S100A8/A9 (calprotectin) has shown promise as a biomarker for predicting relapse in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study was undertaken to investigate serum S100A8/A9 level as a biomarker for predicting future relapse in a large cohort of patients with severe AAV.

METHODS

Serum levels of S100A8/A9 were measured at baseline and months 1, 2, and 6 following treatment initiation in 144 patients in the Rituximab in ANCA-Associated Vasculitis trial (cyclophosphamide/azathioprine versus rituximab [RTX] for induction of remission) in whom complete remission was attained.

RESULTS

Patients were divided into 4 groups: proteinase 3 (PR3)-ANCA with relapse (n = 37), PR3-ANCA without relapse (n = 56), myeloperoxidase (MPO)-ANCA with relapse (n = 6), and MPO-ANCA without relapse (n = 45). Serum S100A8/A9 level decreased in all groups during the first 6 months of treatment. The percentage reduction from baseline to month 2 was significantly different between patients who experienced a relapse and those who did not in the PR3-ANCA group (P = 0.046). A significantly higher risk of relapse was associated with an increase in S100A8/A9 level between baseline and month 2 (P = 0.0043) and baseline and month 6 (P = 0.0029). Subgroup analysis demonstrated that patients treated with RTX who had increased levels of S100A8/A9 were at greatest risk of future relapse (P = 0.028).

CONCLUSION

An increase in serum S100A8/A9 level by month 2 or 6 compared to baseline identifies a subgroup of PR3-ANCA patients treated with RTX who are at higher risk of relapse by 18 months. Since RTX is increasingly used for remission induction in PR3-ANCA-positive patients experiencing a relapse, S100A8/A9 level may assist in identifying those patients requiring more intensive or prolonged treatment.

Association of IgG4-Related Disease With History of Malignancy

OBJECTIVE

IgG4-related disease (IgG4-RD) is a fibroinflammatory disease of unclear etiology. Some studies suggest that IgG4-RD predisposes patients to malignancy or is a forme fruste of cancer, but we have frequently observed IgG4-RD patients who have a history of malignancy preceding the clinical onset of IgG4-RD. This study was undertaken to characterize IgG4-RD in the setting of previous malignancy diagnosis.

METHODS

We identified IgG4-RD patients with a history of invasive malignancy from a well-defined cohort of 125 patients and compared their malignancy history to those of 2 reference groups. First, we calculated a standardized prevalence ratio against general US population estimates from the Surveillance, Epidemiology, and End Results (SEER) database. Second, we identified up to 5 age- and sex-matched controls for each case and calculated the odds of malignancy among those with IgG4-RD compared to controls, using conditional logistic regression.

RESULTS

The mean ± SD age at IgG4-RD onset was 50.3 ± 14.9 years, and 61% of the patients were male. Twenty (16%) had been diagnosed as having malignancies (total 21 malignancies) before the diagnosis of IgG4-RD. The observed prevalence of malignancy in this cohort was 2.5 times higher (95% confidence interval [95% CI] 1.1-3.6) than expected compared to the SEER database. Compared to matched controls, the frequency of history of malignancy was >3-fold higher in IgG4-RD patients (95% CI 1.6-6.2).

CONCLUSION

Our findings suggest that, in a subset of patients with IgG4-RD, malignancy may be associated with subsequent IgG4-RD development. Potential explanations include shared risk factors for both IgG4-RD and cancer, the triggering by cancer of autoantigen expression leading to IgG4-RD, and an increased risk of IgG4-RD resulting from cancer treatment.

Factors Determining the Clinical Utility of Serial Measurements of Antineutrophil Cytoplasmic Antibodies Targeting Proteinase 3

OBJECTIVE

Relapse following remission is common in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), particularly with ANCAs directed at proteinase 3 (PR3). This study was undertaken to evaluate the association of an increase in PR3-ANCA level with subsequent relapse.

METHODS

Data from the Rituximab versus Cyclophosphamide for ANCA-Associated Vasculitis (RAVE) trial were used. Starting from the time of achieving complete remission, serial measurements by direct and capture enzyme-linked immunosorbent assays (ELISAs) were analyzed in 93 patients with PR3-ANCA, using Cox proportional hazards regression.

RESULTS

An increase in PR3-ANCA level was identified in 58 of 93 subjects (62.4%) by direct ELISA and in 59 of 93 (63.4%) by capture ELISA. Relapses occurred in 55 of 93 subjects (59.1%), with 25 and 21 occurring within 1 year after an increase by direct ELISA and capture ELISA, respectively. An increase by direct ELISA was associated with subsequent severe relapses (hazard ratio [HR] 4.57; P < 0.001), particularly in patients presenting with renal involvement (HR 7.94; P < 0.001) and alveolar hemorrhage (HR 24.19; P < 0.001). Both assays identified increased risk for severe relapse in the rituximab group (HR 5.80; P = 0.002 for direct ELISA and HR 4.54; P = 0.007 for capture ELISA) but not the cyclophosphamide/azathioprine group (P = 0.103 and P = 0.197, respectively).

CONCLUSION

The association of an increase in PR3-ANCA level with the risk of subsequent relapse is partially affected by the PR3-ANCA detection methodology, disease phenotype, and remission induction treatment. An increase in PR3-ANCA level during complete remission conveys an increased risk of relapse, particularly severe relapse, among patients with renal involvement or alveolar hemorrhage and those treated with rituximab. Serial measurements of PR3-ANCA may be informative in this subset of patients, but the risk of relapse must be weighed carefully against the risks associated with therapy.