Significance of clinical-immunological patterns and diagnostic yield of biopsies in microscopic polyangiitis and granulomatosis with polyangiitis.

BACKGROUND: Microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) are the two major antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). OBJECTIVES: To characterize a homogenous AAV cohort and to assess the impact of clinicopathological profiles and ANCA serotypes on clinical presentation and prognosis. Clinical differences in GPA patients according to ANCA serotype and the diagnostic yield for vasculitis of biopsies in different territories were also investigated. RESULTS: This retrospective study (2000-2021) included 152 patients with AAV (77 MPA/75 GPA). MPA patients (96.1% myeloperoxidase [MPO]-ANCA and 2.6% proteinase 3 [PR3]-ANCA) presented more often with weight loss, myalgia, renal involvement, interstitial lung disease (ILD), cutaneous purpura, and peripheral nerve involvement. Patients with GPA (44% PR3-ANCA, 33.3% MPO, and 22.7% negative/atypical ANCA) presented more commonly with ear, nose, and throat and eye/orbital manifestations, more relapses, and higher survival than patients with MPA. GPA was the only independent risk factor for relapse. Poor survival predictors were older age at diagnosis and peripheral nerve involvement. ANCA serotypes differentiated clinical features in a lesser degree than clinical phenotypes. A mean of 1.5 biopsies were performed in 93.4% of patients in different territories. Overall, vasculitis was identified in 80.3% (97.3% in MPA and 61.8% in GPA) of patients. CONCLUSIONS: The identification of GPA presentations associated with MPO-ANCA and awareness of risk factors for relapse and mortality are important to guide proper therapeutic strategies in AAV patients. Biopsies of different affected territories should be pursued in difficult-to-diagnose patients based on their significant diagnostic yield.

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

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

Kinin B1 Receptor Is Important in the Pathogenesis of Myeloperoxidase-Specific ANCA GN.

BACKGROUND: Myeloperoxidase-specific ANCA (MPO-ANCA) are implicated in the pathogenesis of vasculitis and GN. Kinins play a major role during acute inflammation by regulating vasodilatation and vascular permeability and by modulating adhesion and migration of leukocytes. Kinin system activation occurs in patients with ANCA vasculitis. Previous studies in animal models of GN and sclerosing kidney diseases have demonstrated protective effects of bradykinin receptor 1 (B1R) blockade via interference with myeloid cell trafficking. METHODS: To investigate the role of B1R in a murine model of MPO-ANCA GN, we evaluated effects of B1R genetic ablation and pharmacologic blockade. We used bone marrow chimeric mice to determine the role of B1R in bone marrow-derived cells (leukocytes) versus nonbone marrow-derived cells. We elucidated mechanisms of B1R effects using in vitro assays for MPO-ANCA-induced neutrophil activation, endothelial adherence, endothelial transmigration, and neutrophil adhesion molecule surface display. RESULTS: B1R deficiency or blockade prevented or markedly reduced ANCA-induced glomerular crescents, necrosis, and leukocyte influx in mice. B1R was not required for in vitro MPO-ANCA-induced neutrophil activation. Leukocyte B1R deficiency, but not endothelial B1R deficiency, decreased glomerular neutrophil infiltration induced by MPO-ANCA in vivo. B1R enhanced ANCA-induced neutrophil endothelial adhesion and transmigration in vitro. ANCA-activated neutrophils exhibited changes in Mac-1 and LFA-1, important regulators of neutrophil endothelial adhesion and transmigration: ANCA-activated neutrophils increased surface expression of Mac-1 and increased shedding of LFA-1, whereas B1R blockade reduced these effects. CONCLUSIONS: The leukocyte B1R plays a critical role in the pathogenesis of MPO-ANCA-induced GN in a mouse model by modulating neutrophil-endothelial interaction. B1R blockade may have potential as a therapy for ANCA GN and vasculitis.

Pathogenesis of ANCA-Associated Pulmonary Vasculitis.

Antineutrophil cytoplasmic antibodies (ANCAs) are autoantibodies specific for antigens located in the cytoplasmic granules of neutrophils and lysosomes of monocytes. ANCAs are associated with a spectrum of necrotizing vasculitis that includes granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis. Pulmonary vasculitis and related extravascular inflammation and fibrosis are frequent components of ANCA vasculitis. In this review, we detail the factors that have been associated with the origin of the ANCA autoimmune response and summarize the most relevant clinical observations, in vitro evidence, and animal studies strongly indicating the pathogenic potential of ANCA. In addition, we describe the putative sequence of pathogenic mechanisms driven by ANCA-induced activation of neutrophils that result in small vessel necrotizing vasculitis and extravascular granulomatous necrotizing inflammation.

Endothelin-1 promotes vascular smooth muscle cell migration across the artery wall: a mechanism contributing to vascular remodelling and intimal hyperplasia in giant-cell arteritis.

BACKGROUND: Giant-cell arteritis (GCA) is an inflammatory disease of large/medium-sized arteries, frequently involving the temporal arteries (TA). Inflammation-induced vascular remodelling leads to vaso-occlusive events. Circulating endothelin-1 (ET-1) is increased in patients with GCA with ischaemic complications suggesting a role for ET-1 in vascular occlusion beyond its vasoactive function. OBJECTIVE: To investigate whether ET-1 induces a migratory myofibroblastic phenotype in human TA-derived vascular smooth muscle cells (VSMC) leading to intimal hyperplasia and vascular occlusion in GCA. METHODS AND RESULTS: Immunofluorescence/confocal microscopy showed increased ET-1 expression in GCA lesions compared with control arteries. In inflamed arteries, ET-1 was predominantly expressed by infiltrating mononuclear cells whereas ET receptors, particularly ET-1 receptor B (ETBR), were expressed by both mononuclear cells and VSMC. ET-1 increased TA-derived VSMC migration in vitro and α-smooth muscle actin (αSMA) expression and migration from the media to the intima in cultured TA explants. ET-1 promoted VSMC motility by increasing activation of focal adhesion kinase (FAK), a crucial molecule in the turnover of focal adhesions during cell migration. FAK activation resulted in Y397 autophosphorylation creating binding sites for Src kinases and the p85 subunit of PI3kinases which, upon ET-1 exposure, colocalised with FAK at the focal adhesions of migrating VSMC. Accordingly, FAK or PI3K inhibition abrogated ET-1-induced migration in vitro. Consistently, ET-1 receptor A and ETBR antagonists reduced αSMA expression and delayed VSMC outgrowth from cultured GCA-involved artery explants. CONCLUSIONS: ET-1 is upregulated in GCA lesions and, by promoting VSMC migration towards the intimal layer, may contribute to intimal hyperplasia and vascular occlusion in GCA.

Pulmonary Involvement in Systemic Vasculitis.

PURPOSE OF REVIEW: The purpose of this study is to describe the most relevant advances concerning lung involvement in the ANCA-associated vasculitides (excluding eosinophilic granulomatosis with polyangiitis which may have different disease mechanisms). Focus is on pathophysiology, recent important imagenological procedures, treatment, and outcome. RECENT FINDINGS: Emerging information exists on potential newly investigated diagnostic procedures (v.g. transbronchial cryobiopsies), detailed tomographic abnormalities, the potential favorable role of rituximab and the still uncertain one of plasma exchange in the treatment, and the increasing description of interstitial lung disease. Survival is reduced in case of both, diffuse alveolar hemorrhage and diffuse parenchymal disease. There is the need to expand the knowledge concerning better long-term treatment options with specific regimes, and to incorporate other measures regarding integral treatment in patients afflicted with lung involvement these maladies, as the outcome seems adverse in this scenario.

Blocking interferon γ reduces expression of chemokines CXCL9, CXCL10 and CXCL11 and decreases macrophage infiltration in ex vivo cultured arteries from patients with giant cell arteritis.

BACKGROUND: Interferon γ (IFNγ) is considered a seminal cytokine in the pathogenesis of giant cell arteritis (GCA), but its functional role has not been investigated. We explored changes in infiltrating cells and biomarkers elicited by blocking IFNγ with a neutralising monoclonal antibody, A6, in temporal arteries from patients with GCA. METHODS: Temporal arteries from 34 patients with GCA (positive histology) and 21 controls were cultured on 3D matrix (Matrigel) and exposed to A6 or recombinant IFNγ. Changes in gene/protein expression were measured by qRT-PCR/western blot or immunoassay. Changes in infiltrating cells were assessed by immunohistochemistry/immunofluorescence. Chemotaxis/adhesion assays were performed with temporal artery-derived vascular smooth muscle cells (VSMCs) and peripheral blood mononuclear cells (PBMCs). RESULTS: Blocking endogenous IFNγ with A6 abrogated STAT-1 phosphorylation in cultured GCA arteries. Furthermore, selective reduction in CXCL9, CXCL10 and CXCL11 chemokine expression was observed along with reduction in infiltrating CD68 macrophages. Adding IFNγ elicited consistent opposite effects. IFNγ induced CXCL9, CXCL10, CXCL11, CCL2 and intracellular adhesion molecule-1 expression by cultured VSMC, resulting in increased PBMC chemotaxis/adhesion. Spontaneous expression of chemokines was higher in VSMC isolated from GCA-involved arteries than in those obtained from controls. Incubation of IFNγ-treated control arteries with PBMC resulted in adhesion/infiltration by CD68 macrophages, which did not occur in untreated arteries. CONCLUSIONS: Our ex vivo system suggests that IFNγ may play an important role in the recruitment of macrophages in GCA by inducing production of specific chemokines and adhesion molecules. Vascular wall components (ie, VSMC) are mediators of these functions and may facilitate progression of inflammatory infiltrates through the vessel wall.

[Clinical Characteristics of antineutrophil cytoplasmic antibody-associated vasculitis in a respiratory diseases referral center in Mexico (1982-2010)]. / Vasculitis asociadas a anticuerpos anticitoplasma de neutrófilos (ANCA) en un centro de tercer nivel de enfermedad respiratoria (1982-2010).

INTRODUCTION: Respiratory manifestations in antineutrophil cytoplasmic antibody-associated vasculitis (AASV) are common, though their suspicion is lower than expected in respiratory devoted centers, with few descriptions coming from them. OBJECTIVE: To describe the clinical, paraclinical and radiological manifestations, plus the prognosis of AASV patients seen in a respiratory referral center in Mexico City. MATERIAL AND METHODS: Retrospective review of patients with final diagnosis of AASV, based on the American College of Rheumatology criteria and the 1994 Chapel Hill Consensus Conference Nomenclature, from 1982 to 2010. RESULTS: The characteristics of 74 granulomatosis with polyangiitis, 10 microscopic polyangiitis, and six eosinophilic granulomatosis with polyangiitis cases are described. Mean time elapsed from initial suspicion to definitive diagnosis was 30 months. As expected, respiratory findings dominated this cohort, but no significant differences were observed when compared to other series with AAS\1, except for a higher frequency of subglottic stenosis. After a mean follow-up of 22 months, 83% of patients were alive, with remission being achieved in 87% and response in 9%. Seven patients died, mostly from infectious complications. CONCLUSION: This study documents that airway manifestations in Mexican patients with AASV are similar to what has been previously described. However, time to diagnosis is long. Respiratory specialists should be more aware of the modes of presentation in AASV patients in order to facilitate their recognition.

Prospective long term follow-up of a cohort of patients with giant cell arteritis screened for aortic structural damage (aneurysm or dilatation).

BACKGROUND: Aortic structural damage (ASD) may complicate the course of patients with giant cell arteritis (GCA). However the frequency and outcome of ASD has not been assessed in long term prospective studies. METHODS: In a previous screening of 54 biopsy proven GCA patients, significant ASD was detected in 12 (22.2%) after a median follow-up of 5.4 years. These patients were periodically evaluated (every 4 years) over a median of 10.3 years (range 4-16.6 years) in order to investigate the development of new ASD and the outcome of previously detected abnormalities. RESULTS: 18 of the 54 patients abandoned the study due to death or other reasons. The remaining 36 patients were subjected to a second screening and 14 to a third screening. 12 (33.3%) of the 36 patients re-screened and 16 (29.6%) of the initial cohort developed ASD, all but one in the thoracic aorta. Aortic diameters at the ascending and descending aorta significantly increased over time. One patient (1.9% of the initial cohort) died from aortic dissection. Surgery was advised in eight (50%) patients with ASD but could only be performed in three patients (37.7%). The development of ASD was not associated with persistence of detectable disease activity. CONCLUSIONS: The incidence of ASD is maximal within the first 5 years after diagnosis but continues developing over time, affecting up to 33.3% of individuals after long term follow-up. Once ASD occurs, dilatation increases over time, underlining the need for periodic evaluation. Surgical repair is feasible in about one-third of candidates.

Positron emission tomography assessment of large vessel inflammation in patients with newly diagnosed, biopsy-proven giant cell arteritis: a prospective, case-control study.

BACKGROUND: Positron emission tomography (PET) scan is emerging as a promising imaging technique to detect large-vessel inflammation in giant cell arteritis (GCA). However, the lack of a standardised definition of arteritis based on (18)fluorodeoxyglucose (FDG) uptake is an important limitation to the use of PET scan for diagnostic purposes. OBJECTIVE: To prospectively assess the intensity and distribution of FDG uptake at different vascular territories in patients with newly diagnosed GCA compared with controls. METHODS: 32 consecutive, biopsy-proven, GCA patients treated with glucocorticoids for ≤3 days were included. The control group consisted of 20 individuals, who underwent PET/CT for cancer staging. Maximal standardised uptake value (SUVm) was calculated at four aortic segments, supraaortic branches and iliac-femoral territory. Sensitivity and specificity was calculated by receiver-operator characteristic curves (ROC) analysis. RESULTS: Mean SUVm was significantly higher in patients than in controls in all vessels explored and correlated with acute-phase reactants and serum IL-6. Mean of the SUVm at all the vascular territories had an area under the curve (AUC) of 0.830, and a cut-off of 1.89 yielded a sensitivity of 80% and a specificity of 79% for GCA diagnosis. There were no significant differences in AUC among the vascular beds examined. CONCLUSIONS: FDG uptake by large vessels has a substantial sensitivity and specificity for GCA diagnosis.

Changes in biomarkers after therapeutic intervention in temporal arteries cultured in Matrigel: a new model for preclinical studies in giant-cell arteritis.

BACKGROUND: Search for therapeutic targets in giant-cell arteritis (GCA) is hampered by the scarcity of functional systems. We developed a new model consisting of temporal artery culture in tri-dimensional matrix and assessed changes in biomarkers induced by glucocorticoid treatment. METHODS: Temporal artery sections from 28 patients with GCA and 22 controls were cultured in Matrigel for 5 days in the presence or the absence of dexamethasone. Tissue mRNA concentrations of pro-inflammatory mediators and vascular remodelling molecules was assessed by real-time RT-PCR. Soluble molecules were measured in the supernatant fluid by immunoassay. RESULTS: Histopathological features were exquisitely preserved in cultured arteries. mRNA concentrations of pro-inflammatory cytokines (particularly IL-1ß and IFNγ), chemokines (CCL3/MIP-1α, CCL4/MIP-1ß, CCL5/RANTES) and MMP-9 as well as IL-1ß and MMP-9 protein concentrations in the supernatants were significantly higher in cultured arteries from patients compared with control arteries. The culture system itself upregulated expression of cytokines and vascular remodelling factors in control arteries. This minimised differences between patients and controls but underlines the relevance of changes observed. Dexamethasone downregulated pro-inflammatory mediator (IL-1ß, IL-6, TNFα, IFNγ, MMP-9, TIMP-1, CCL3 and CXCL8) mRNAs but did not modify expression of vascular remodelling factors (platelet derived growth factor, MMP-2 and collagens I and III). CONCLUSIONS: Differences in gene expression in temporal arteries from patients and controls are preserved during temporal artery culture in tri-dimensional matrix. Changes in biomarkers elicited by glucocorticoid treatment satisfactorily parallel results obtained in vivo. This may be a suitable model to explore pathogenetic pathways and to perform preclinical studies with new therapeutic agents.

Diagnosis and classification of polyarteritis nodosa.

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis preferentially targeting medium-sized arteries and not associated with glomerulonephritis or small vessel involvement. Anti-neutrophil cytoplasmic antibodies are typically negative. PAN may be triggered by viral infections, particularly hepatitis B virus, but remains idiopathic in most cases. Clinical manifestations of PAN are multisystemic. Peripheral nerve and skin are the most frequently affected tissues. Involvement of the gastrointestinal tract, kidneys, heart, and central nervous system is associated with higher mortality. Laboratory abnormalities reveal a prominent acute phase response but are non-specific. Histologic confirmation of vasculitis in medium sized arteries is desirable and biopsies must be obtained from symptomatic organs if feasible. Skin or muscle and nerve are preferred because of higher diagnostic yield and safety. If biopsies are negative or cannot be obtained, visceral angiography, may reveal multiple micro-aneurysms supporting the diagnosis of PAN. Current treatment policy includes high-dose corticosteroids, which are combined with immunosuppressive agents when critical organ involvement or life-threatening complications occur. IV pulse cyclophosphamide in the remission induction phase, later switched to a safer immunosuppressant for remission maintenance is a frequently used therapeutic approach. A recent consensus algorithm for the classification of PAN has attempted to overcome some of the caveats of the 1990 American College of Rheumatology (ACR) classification criteria which have proven to be unsatisfactory, and has also confirmed the low prevalence of PAN compared to other systemic necrotizing vasculitides. European league against rheumatic diseases (EULAR)/ACR endorsed international cooperation to establish new diagnostic/classification criteria is currently under way.

Registry of the Spanish network of Behçet's disease: a descriptive analysis of 496 patients.

OBJECTIVES: To describe the clinical features of a large cohort of 496 Spanish patients with Behçet's disease (BD) and to analyse if patient's sex influenced the initial and cumulated prevalence of disease manifestations. METHODS: Retrospective and descriptive study of 496 patients recruited in sixteen centres on the frame of the Spanish Registry of Behçet Disease Project Group. Demographic and clinical data are presented in addition to treatments and their related adverse effects. Clinical features at disease onset and during follow-up were compared according to the sex of the patients. RESULTS: On the whole series, female to male ratio was 1.2:1.0. Mean age at disease onset was 28.7±12.6 years (range 17-73). Oral ulcers were the most frequent initial manifestation presented in 52.0% of patients. During follow-up, eye inflammatory disease was recorded in 45.1% of patients; thrombosis in 19.7% and central nervous system involvement in 13.5%. Men had higher prevalence of ocular involvement and venous thrombosis (52.5% vs. 39.2%, p=0.004 and 26.3% vs. 9.6%, p<0.001, respectively). CONCLUSIONS: Spanish patients with BD presented similar clinical characteristics as their counterpart in the same geographical area and other world regions. In addition, we confirmed that ocular and vascular involvements are more frequent in men than in women.

Maternal and fetal outcomes of pregnancy in women with primary systemic vasculitis: A single-center cohort study of 20 patients and 30 pregnancies.

OBJECTIVES: To analyze pregnancy outcomes of patients with primary systemic vasculitis followed in a third-level referral center. METHODS: Retrospective cohort study of all pregnant women with systemic vasculitis followed between 2009 and 2022 at the High-Risk Pregnancy Clinic of the Department of Systemic Autoimmune Diseases of the Hospital Clínic, Barcelona. RESULTS: Twenty women with primary vasculitis were identified, with a total of 30 pregnancies. Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (n = 7) and Behçet disease (n = 4) were the most frequent types of vasculitis. All women had the diagnosis of vasculitis before pregnancy, with a median time between disease diagnosis and pregnancy of 5.8 years (range: 2 months-29 years). Most were in remission at conception (76.7 %). During pregnancy, a vasculitis flare occurred in 4 (13.3 %) patients (one each with Takayasu arteritis, eosinophilic granulomatosis with polyangiitis [EGPA], IgA vasculitis [IgAV], and Behçet disease [BD]). Four (16.7 %) of the successful pregnancies had post-partum relapses (one each with EGPA, granulomatosis with polyangiitis, IgAV, and BD). Eighty percent of pregnancies resulted in live babies. In four cases (13.3 %), medical termination of pregnancy was decided, considering the mother or baby health risk. There were two spontaneous miscarriages, and no stillbirths or neonatal deaths. Preeclampsia was the most frequent maternal complication (25 %). Newborns were preterm in 24 % and low birthweight in 20 % of cases. No maternal deaths occurred. CONCLUSIONS: This cohort study shows that vasculitis relapses during pregnancy and post-partum, together with other pregnancy complications, occur in a considerable number of patients with systemic vasculitides, although a final good pregnancy outcome can be expected in most cases. These findings emphasize the convenience of managing these special situations in expert reference centers.

Adalimumab for the treatment of Behçet's disease: experience in 19 patients.

OBJECTIVE: To describe the experience of two tertiary Spanish centres (Hospital Clínico San Cecilio, Granada and Hospital Clínic, Barcelona) with the use of adalimumab for the treatment of severe clinical manifestations in patients with Behçet's disease (BD) in whom immunosuppressive therapy had failed. METHODS: Retrospective chart review from patients with BD treated with adalimumab in two specialized Spanish centres (Hospital Clínico San Cecilio, Granada and Hospital Clínic, Barcelona). RESULTS: From November 2006 to February 2011, 19 patients with BD were treated with adalimumab. The reason to initiate adalimumab was refractory disease in 17 (89.5%) patients and adverse events to CSA and infliximab in two (10.5%) patients, respectively. The main clinical manifestations leading to adalimumab administration were panuveitis in eight patients, severe bipolar aphthosis in eight, retinal vasculitis in three and severe folliculitis in three. Overall, adalimumab achieved clinical improvement in 17 of the 19 patients. Of note, ocular manifestations (panuveitis and retinal vasculitis) responded rapidly in all cases. In addition to clinical improvement, treatment with adalimumab was associated with reduction in the number and dose of standard immunosuppressive agents. Of interest, seven patients had received TNF-α inhibitors before adalimumab, five infliximab and the remaining two etanercept. Adalimumab was withdrawn in only one patient due to severe infusional reaction in the form of urticaria and angioedema. CONCLUSION: Adalimumab is a valid option for patients with BD and recalcitrant non-controlling manifestations with good safety profile.

Giant cell arteritis in Mexican patients.

BACKGROUND: Giant cell arteritis (GCA) is the most common primary systemic vasculitis worldwide, although it seems to be very rare in some areas, such as Latin America. OBJECTIVES: The objective of the study was to describe the clinical, laboratory, and treatment features in a Mexican Mestizo population with GCA. METHODS: Retrospective data chart review (1989-2010). RESULTS: Twenty-two patients with GCA were identified, 18 women and 4 men. Mean age was 73 (SD, 7.9) years. Diagnosis was made at a mean of 67 (SD, 83.6) days from symptom onset. Most frequent presenting symptoms included headache (90%), constitutional symptoms (86%), and polymyalgia rheumatica (59%). Severe cranial ischemic complications were present in 32%. Amaurosis fugax and blindness were present in 36% and 27%, respectively. High erythrocyte sedimentation rate was present in 89% of patients. Rapid response to prednisone treatment was seen, but in 10 patients, relapse occurred, possibly related to fast tapering. Additional treatment was methotrexate (n = 8), azathioprine (n = 5), and cyclophosphamide (n = 3). Median follow-up was 242 (SD, 214) weeks. CONCLUSIONS: Giant cell arteritis is rarely recognized in Latin America. We report on characteristics of GCA in a population of Mexican Mestizos, as ours is the largest series to be reported from Latin America so far. When compared with other series, age at onset is similar, females are more affected, and although a good response to corticosteroid treatment was seen, a higher frequency of amaurosis fugax and blindness was observed, accounting for an unfavorable functional outcome in 6 (27%) of 22 patients.

Relevance of Combined Clinicopathologic Phenotype and Antineutrophil Cytoplasmic Autoantibody Serotype in the Diagnosis of Antineutrophil Cytoplasmic Autoantibody Vasculitis.

Introduction: Granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), 2 major clinicopathologic variants of antineutrophil cytoplasmic autoantibody (ANCA) vasculitides, are mostly associated with proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA, respectively. Less is known regarding the uncommon forms of ANCA vasculitis, PR3-ANCA MPA and MPO-ANCA GPA. Methods: In this cohort study we detailed the clinical presentation and outcome of patients with PR3-ANCA MPA and MPO-ANCA GPA from the Glomerular Disease Collaborative Network (GDCN) inception cohort. Baseline clinical manifestations, relapses, end-stage kidney disease (ESKD), and survival were compared within MPA cases by PR3-ANCA (n = 116) versus MPO-ANCA (n = 173) and within GPA cases by PR3-ANCA (n = 108) versus MPO-ANCA (n = 43). Fisher's exact test and Wilcoxon two sample test were used for comparisons. Proportional hazards models were used to evaluate the development of relapses, ESKD, and death. Results: Patients with PR3-ANCA MPA were younger (53 years vs. 62 years, P = 0.0007) and had increased prevalence of joint involvement (56% vs. 40%, P = 0.0115) and ear, nose, and throat (ENT) involvement (44% vs. 26%, P = 0.002) than MPO-ANCA MPA. Relapses, ESKD, and survival were similar between both MPA subsets. Within the GPA group, patients with MPO-ANCA GPA were older (61 years vs. 46 years, P = 0.0007) and more likely female (56% vs. 35%, P = 0.027) than PR3-ANCA GPA patients. MPO-ANCA GPA was also characterized by less prevalent ENT manifestations (58% vs. 77%, P = 0.028) and neurologic manifestations (5% vs. 25%, P = 0.0029), and increased ESKD and mortality. Conclusions: PR3-ANCA MPA and MPO-ANCA GPA are clinicopathologically distinct subsets of ANCA vasculitis that differ from MPO-ANCA MPA and PR3-ANCA GPA. Although the impact of these differences on the clinical management and outcome warrants further evaluation, these results support the recommendation of including both the phenotypic diagnosis and ANCA serotype in the diagnosis of ANCA vasculitis.

Predicting Outcome in Patients with Anti-GBM Glomerulonephritis.

BACKGROUND AND OBJECTIVES: Large studies on long-term kidney outcome in patients with anti-glomerular basement membrane (anti-GBM) GN are lacking. This study aimed to identify clinical and histopathologic parameters that predict kidney outcome in these patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This retrospective analysis included a total of 123 patients with anti-GBM GN between 1986 and 2015 from six centers worldwide. Their kidney biopsy samples were classified according to the histopathologic classification for ANCA-associated GN. Clinical data such as details of treatment were retrieved from clinical records. The primary outcome parameter was the occurrence of ESRD. Kidney survival was analyzed using the log-rank test and Cox regression analyses. RESULTS: The 5-year kidney survival rate was 34%, with an improved rate observed among patients diagnosed after 2007 (P=0.01). In patients with anti-GBM GN, histopathologic class and kidney survival were associated (P<0.001). Only one of 15 patients with a focal class biopsy sample (≥50% normal glomeruli) developed ESRD. Patients with a sclerotic class biopsy sample (≥50% globally sclerotic glomeruli) and patients with 100% cellular crescents did not recover from dialysis dependency at presentation. In multivariable analysis, dialysis dependency at presentation (hazard ratio [HR], 3.17; 95% confidence interval [95% CI], 1.59 to 6.32), percentage of normal glomeruli (HR, 0.97; 95% CI, 0.95 to 0.99), and extent of interstitial infiltrate (HR, 2.02; 95% CI, 1.17 to 3.50) were predictors of ESRD during follow-up. CONCLUSIONS: Dialysis dependency, low percentage of normal glomeruli, and large extent of interstitial infiltrate are associated with poor kidney outcome in anti-GBM GN. Kidney outcome has improved during recent years; the success rate doubled after 2007. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2017_11_21_CJASNPodcast_18_1_v.mp3.

Interstital lung disease in ANCA vasculitis.

Anti-neutrophil cytoplasmic antibodies (ANCA) vasculitides are immune-mediated disorders that primarily affect small blood vessels of the airway and kidneys. Lung involvement, one of the hallmarks of microscopic polyangiitis and granulomatosis with polyangiitis, is associated with increased mortality and morbidity. In recent years, several retrospective series and case reports have described the association of interstitial lung disease (ILD) and ANCA vasculitis, particularly those positive for ANCA specific for myeloperoxidase. In the majority of these patients pulmonary fibrosis occurs concurrently or predates the diagnosis of ANCA vasculitis. More importantly, these studies have shown that ILD has an adverse impact on the long-term prognosis of ANCA vasculitis. This review focuses on the main clinical and radiologic features of pulmonary fibrosis associated with anti-neutrophil cytoplasmic antibodies. Major histopathology features, prognosis and therapeutic options are summarized.