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AbstractBackground and objectivePulmonary capillaritis is generally secondary to a systemic autoimmune process. Little is known regarding other causes of pulmonary capillaritis, particularly isolated pulmonary capillaritis (IPC). IPC is defined as pulmonary capillaritis in the absence of evidence of a systemic disease. We aim to describe the aetiology of biopsy‐proven pulmonary capillaritis to add to the existing knowledge on aetiologies of pulmonary capillaritis and provide a more detailed description of IPC cases.MethodsA retrospective cohort of biopsy‐proven pulmonary capillaritis was conducted at the Mayo Clinic, Rochester over a 17‐year period. Histologic slides were re‐reviewed by a lung pathologist. Medical records were reviewed to identify a possible aetiology of the pulmonary capillaritis. A subset analysis of patients identified with IPC was then performed.ResultsThirty‐six cases of biopsy‐proven pulmonary capillaritis were identified. The majority of cases were secondary to a systemic autoimmune disease, most commonly granulomatosis with polyangiitis. There were four cases of IPC in this cohort. Median follow‐up was 116.5 months with no evidence of systemic disease development. No risk factors for IPC were identified. All patients presented sub‐acutely with haemoptysis and diffuse alveolar haemorrhage with a delay in diagnosis. After initiation of immunosuppression, most patients obtained remission with a benign clinical course.ConclusionPulmonary capillaritis is most commonly secondary to systemic autoimmune disorders, predominantly ANCA‐associated vasculitis. IPC is a rare form of pulmonary capillaritis with very few cases described in the literature, the availability of effective treatment makes this rare disease important to recognize.

Objective To identify predictors of respiratory failure and to evaluate the therapeutic efficacy of plasma exchange (PE) and of rituximab versus cyclophosphamide in a cohort of patients with diffuse alveolar hemorrhage (DAH) secondary to antineutrophil cytoplasmic antibody–associated vasculitis (AAV) with or without respiratory failure. Methods We performed a single‐center historical cohort study of all consecutive patients with AAV‐associated DAH who were evaluated over a 16‐year period. Logistic regression models were developed to examine the predictive role of the baseline clinical characteristics for the development of respiratory failure, and for the effect of PE and remission induction therapy on the main outcome (complete remission at 6 months). Results Seventy‐three patients with DAH were identified, and 34 of them experienced respiratory failure. The degree of hypoxemia upon initial presentation, a higher percentage of neutrophils in the bronchoalveolar lavage fluid cell count, and higher C‐reactive protein levels were independently associated with the development of respiratory failure. PE was not associated with achieving complete remission at 6 months, with an odds ratio (OR) of 0.49 (95% confidence interval [95% CI] 0.12–1.95) ( P = 0.32). Rituximab treatment was independently associated with achieving complete remission at 6 months (OR 6.45 [95% CI 1.78–29], P = 0.003). Conclusion Our findings indicate that the most important predictor of respiratory failure in patients with DAH secondary to AAV is the degree of hypoxemia upon presentation. No clear benefit of the addition of PE to standard remission induction therapy was demonstrated. Complete remission by 6 months was achieved at a higher rate with rituximab than with cyclophosphamide in patients with DAH secondary to AAV, including those needing mechanical ventilation.

ObjectiveTo discover biomarkers involved in the pathophysiology of antineutrophil cytoplasmic antibody–associated vasculitis (AAV) and to determine whether low‐density granulocytes (LDGs) contribute to gene expression signatures in AAV.MethodsThe source of clinical data and linked biologic specimens was a randomized controlled treatment trial in AAV. RNA sequencing of whole blood from patients with AAV was performed during active disease at the baseline visit and during remission 6 months later. Gene expression was compared between patients who met versus those who did not meet the primary trial outcome of clinical remission at 6 months (responders versus nonresponders). Measurement of neutrophil‐related gene expression was confirmed in peripheral blood mononuclear cells (PBMCs) to validate the findings in whole blood. A negative‐selection strategy isolated LDGs from PBMC fractions.ResultsDifferential expression between responders (n = 77) and nonresponders (n = 35) was detected in 2,346 transcripts at the baseline visit (P < 0.05). Unsupervised hierarchical clustering demonstrated a cluster of granulocyte‐related genes, including myeloperoxidase (MPO) and proteinase 3 (PR3). A granulocyte multigene composite score was significantly higher in nonresponders than in responders (P < 0.01) and during active disease than during remission (P < 0.01). This signature strongly overlapped an LDG signature identified previously in lupus (false discovery rate by gene set enrichment analysis <0.01). Transcription of PR3 measured in PBMCs was associated with active disease and treatment response (P < 0.01). LDGs isolated from patients with AAV spontaneously formed neutrophil extracellular traps containing PR3 and MPO.ConclusionIn AAV, increased expression of a granulocyte gene signature is associated with disease activity and decreased response to treatment. The source of this signature is likely LDGs, a potentially pathogenic cell type in AAV.

ObjectiveNonsevere relapses are more common than severe relapses in antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV), but their clinical course and treatment outcomes remain largely unexamined. We undertook this study to analyze the outcomes of patients with nonsevere relapses in the Rituximab in ANCA‐Associated Vasculitis (RAVE) trial who were treated with prednisone according to a prespecified protocol.MethodsRAVE was a randomized, double‐blind, placebo‐controlled trial comparing rituximab (RTX) to cyclophosphamide (CYC) followed by azathioprine (AZA) for induction of remission. Patients who experienced nonsevere relapses between months 1 and 18 were treated with a prednisone increase without a concomitant change in their nonglucocorticoid immunosuppressants, followed by a taper.ResultsForty‐four patients with a first nonsevere relapse were analyzed. In comparison to the 71 patients who maintained relapse‐free remission over 18 months, these patients were more likely to have proteinase 3–ANCAs, diagnoses of granulomatosis with polyangiitis (Wegener's), and a history of relapsing disease at baseline. A prednisone increase led to remission in 35 patients (80%). However, only 13 patients (30%) were able to maintain second remissions through the followup period (mean 12.5 months); 31 patients (70%) had a second disease relapse, 14 of them with severe disease. The mean time to second relapse was 9.4 months (4.7 months in the group treated with RTX versus 13.7 months in the group treated with CYC/AZA; P < 0.01). Patients who experienced nonsevere relapses received more glucocorticoids than those who maintained remission (6.7 grams versus 3.8 grams; P < 0.01).ConclusionTreatment of nonsevere relapses in AAV with an increase in glucocorticoids is effective in restoring temporary remission in the majority of patients, but recurrent relapses within a relatively short interval remain common. Alternative treatment approaches are needed for this important subset of patients.

ObjectiveCD5+ B cells have been conceptualized as a possible surrogate for Breg cells. The aim of the present study was to determine the utility of CD5+ B cells as biomarkers in antineutrophil cytoplasmic antibody–associated vasculitis (AAV).MethodsThe absolute and relative numbers (percentages) of CD5+ B cells (explanatory variables) were measured longitudinally during 18 months in 197 patients randomized to receive either rituximab (RTX) or cyclophosphamide (CYC) followed by azathioprine (AZA) for the treatment of AAV (Rituximab in ANCA‐Associated Vasculitis [RAVE] trial). Outcome variables included disease activity (status of active disease versus complete remission), responsiveness to induction therapy, disease relapse, disease severity, and, in RTX‐treated patients, relapse‐free survival according to the percentage of CD5+ B cells detected upon B cell repopulation.ResultsCD5+ B cell numbers were comparable between the treatment groups at baseline. After an initial decline, absolute CD5+ B cell numbers progressively increased in patients in the RTX treatment arm, but remained low in CYC/AZA‐treated patients. In both groups, the percentage of CD5+ B cells increased during remission induction and slowly declined thereafter. During relapse, the percentage of CD5+ B cells correlated inversely with disease activity in RTX‐treated patients, but not in patients who received CYC/AZA. No significant association was observed between the numbers of CD5+ B cells and induction treatment failure or disease severity. The dynamics of the CD5+ B cell compartment did not anticipate disease relapse. Following B cell repopulation, the percentage of CD5+ B cells was not predictive of time to flare in RTX‐treated patients.ConclusionThe percentage of peripheral CD5+ B cells might reflect disease activity in RTX‐treated patients. However, sole staining for CD5 as a putative surrogate marker for Breg cells did not identify a subpopulation of B cells with clear potential for meaningful clinical use. Adequate phenotyping of Breg cells is required to further explore the value of these cells as biomarkers in AAV.

ObjectiveDisease relapses are frequent in antineutrophil cytoplasmic antibody–associated vasculitis (AAV). This study was undertaken to evaluate outcomes in patients with AAV who are re‐treated with rituximab (RTX) and prednisone for severe disease relapses.MethodsThe Rituximab in AAV trial was a randomized, double‐blind, placebo‐controlled trial comparing the rates of remission induction among patients treated with RTX (n = 99) and patients treated with cyclophosphamide (CYC) followed by azathioprine (AZA) (n = 98). Prednisone was tapered to discontinuation after 5.5 months. After remission was achieved, patients who experienced a severe disease relapse between months 6 and 18 were eligible to receive RTX and prednisone on an open‐label basis according to a prespecified protocol. Investigators remained blinded with regard to the original treatment assignment.ResultsTwenty‐six patients received RTX for disease relapse after remission had initially been achieved with their originally assigned treatment. Fifteen of these patients were initially randomized to receive RTX and 11 to receive CYC/AZA. Thirteen (87%) of the patients originally assigned to receive RTX and 10 (91%) originally assigned to receive CYC/AZA achieved remission again with open‐label RTX (an overall percentage of 88%). In half of the patients treated with open‐label RTX, prednisone could be discontinued entirely. Patients in this cohort experienced fewer adverse events compared to the overall study population (4.7 adverse events per patient‐year versus 11.8 adverse events per patient‐year).ConclusionRe‐treatment of AAV relapses with RTX and glucocorticoids appears to be a safe and effective strategy, regardless of previous treatment.

Prior to the 1970s, severe cases of antineutrophil cytoplasmic antibody associated vasculitis (AAV) were thought to be invariably fatal. However, the use of cyclophosphamide-based treatment regimens fundamentally altered disease outcomes, transforming AAV into a manageable, chronic illness. Despite the tremendous success of cyclophosphamide in the treatment of AAV, there remained a need for alternative therapies, due to high rates of treatment failures and significant toxicities. In recent years, with the introduction of targeted biologic response modifiers into clinical practice, many have hoped that the treatment options for AAV could be expanded. Rituximab, a chimeric monoclonal antibody directed against the B-lymphocyte protein CD20, has been the most successful biologic response modifier to be used in AAV. Following the first report of its use in AAV in 2001, experience with rituximab for treatment of AAV has rapidly expanded. Rituximab, in combination with glucocorticosteroids, is now well established as a safe and effective alternative to cyclophosphamide for remission induction for severe manifestations of granulomatosis with polyangiitis and microscopic polyangiitis. In addition, initial experiences with rituximab for remission maintenance in these diseases have been favorable, as have experiences for remission induction in eosinophilic granulomatosis with polyangiitis.

ObjectiveTo 1) describe the distribution of patient global assessment (PtGA) scores of disease activity in patients with granulomatosis with polyangiitis (GPA; Wegener's), 2) explore the discordance between PtGA scores and physician global assessment (PhGA) scores of disease activity, and 3) explore whether PtGA scores during disease remission are associated with future disease relapse.MethodsData from the Wegener's Granulomatosis Etanercept Trial (WGET) were used. PtGA and PhGA scores were assessed on 100‐mm visual analog scales (VAS). Presence of active disease was determined using the Birmingham Vasculitis Activity Score for WG (BVAS/WG), and remission was defined as a BVAS/WG score of 0. Disease relapse was defined as a BVAS/WG score of >0 after remission had been achieved. Discordance between PtGA and PhGA scores was defined as a difference of ≥20 points between the two measures. Mixed linear models were used in longitudinal analysis of PtGA scores.ResultsData were obtained from 180 patients in the WGET cohort, seen at a total of 1,719 study visits. The mean ± SD PtGA and PhGA disease activity scores (on 100‐mm VAS) at baseline were 64.2 ± 27.4 and 55.5 ± 23.4, respectively. PtGA–PhGA discordance occurred in 53% of patients at baseline, and this was inversely associated with newly diagnosed disease (as opposed to relapsing disease) at baseline (odds ratio 0.37, 95% confidence interval [95% CI] 0.20–0.68) but not with age, sex, or presence of renal or pulmonary disease. Patients were in disease remission during 62% of the study visits. The mean PtGA score during visits immediately prior to relapse was 4.52 points higher (95% CI 0.66–8.4) than that at other remission visits (P = 0.03).ConclusionPtGA–PhGA discordance is common in GPA. A rise in the PtGA disease activity score during times defined by physicians as periods of remission is associated with subsequent occurrence of disease relapse. These findings support the addition of PtGA as an outcome measure for GPA.