Smoking habits in patients diagnosed with ANCA associated small vessel vasculitis

Insights into the paradoxical effect of smoking on vasculitis: a comprehensive review

Vasculitis is a group of uncommon diseases characterized by inflammation of blood vessels, which contributes to the organ ischemia and damage. Cigarette smoke contains a high concentration of various toxins, which have the potential to affect the immune response and development of autoimmune/autoinflammatory rheumatic diseases including vasculitis. Smoking influences both innate and adaptive immune systems and plays binary functions in modulating immunity by either aggravating pathogenic immune responses or attenuating defensive immunity. Smoking contributes to the pathogenesis of autoimmune diseases by various mechanisms including induction of tissue damage and apoptosis, changes in innate immune function and production of proinflammatory cytokines, changes in humoral immunity and T cell responses and anti-estrogen effects. In this review, we considered the available evidence on the association between smoking with the risk, clinical manifestations, response to treatment and outcomes of vasculitis, and the effect of smoking cessation on these parameters. In conclusion, despite inconclusive evidence of an increased risk of giant cell arthritis and anti-neutrophil cytoplasmic autoantibody associated vasculitis (AAV) in smokers, there is strong evidence that smokers have a lower risk of Behcet's disease (BD). Furthermore, smoking changes the clinical picture and outcomes of BD and AAV.

Cigarette smoking and risk of adult-onset Still disease: a propensity score matching analysis

BACKGROUND

Environmental factors play an important role in the pathogenesis of rheumatic diseases. Smoking is thought to be a risk factor for autoimmune rheumatic diseases.

AIMS

The purpose of the present study was to assess the association between smoking and adult-onset Still disease (AOSD) and the effect of smoking on outcomes of this disease.

METHODS

In this case-control study, patients with AOSD who met the Yamaguchi criteria, were older than 16 years at the disease onset and were in follow-up for at least 12 months were consecutively enrolled in the study. The outcome of AOSD was assessed by acquiring remission on treatment, remission off treatment, time to remission and rate of flare. The smoking status of participants was defined by direct or phone interviews. Individuals who had smoked daily for at least 6 months were defined as a smoker. We performed propensity score matching analyses by using four parameters, including age, sex, educational status and marital status.

RESULTS

Propensity score matching resulted in 72 patients with AOSD and 216 matched controls. The number of ever smokers in the AOSD and control groups were 11 (15.3%) and 25 (11.6%) respectively. There was no significant increase in the risk of AOSD in multivariate analysis after adjustment for age, sex, marital status and educational level. There were no significant differences in the outcomes of AOSD between ever and never smokers.

CONCLUSIONS

Smoking probably is not a risk factor for AOSD and did not affect the response to treatment.

Environmental Triggers for Vasculitis

Systemic vasculitides are autoimmune diseases characterized by vascular inflammation. Most types of vasculitis are thought to result from antigen exposure in genetically susceptible individuals, suggesting a likely role for environmental triggers in these conditions. Seasonal and geographic variations in incidence provide insight into the potential role of environmental exposures in these diseases. Many data support infectious triggers in some vasculitides, whereas other studies have identified noninfectious triggers, such as airborne pollutants, silica, smoking, and heavy metals. We review the known and suspected environmental triggers in giant cell arteritis, Takayasu arteritis, polyarteritis nodosa, Kawasaki disease, and antineutrophil cytoplasmic antibody-associated vasculitis.

Diagnosing and treating ANCA-associated vasculitis: an updated review for clinical practice

ANCA-associated vasculitides (AAV) are a group of rare, primary, systemic necrotizing small-vessel vasculitides. Granulomatosis with polyangiitis and microscopic polyangiitis account for ∼80–90% of all AAV. Exposure to silica dust, farming and chronic nasal Staphylococcus aureus carriage are associated with increased risk of developing AAV. When a diagnosis of AAV is suspected, as in patients with multisystem organ dysfunction or those with features such as chronic recurrent rhinosinusitis, cavitated lung nodules, palpable purpura or acute kidney injury, then appropriate further investigations are needed, including ANCA testing. In this scenario, a structured clinical assessment should be conducted, evaluating all the organs possibly involved, and tissue biopsy may be necessary for confirmation of the diagnosis. Therapeutic algorithms vary based on the severity of AAV, the clinical diagnosis/ANCA specificity, and the patient’s age, weight, comorbidities and prognosis. Recent data favour rituximab as a preferable option for both induction and maintenance of remission. In addition, regimens with less glucocorticoids are equally effective and safer in inducing remission compared with conventional regimens, and avacopan is an effective glucocorticoid-sparing option. In contrast, there is not compelling evidence to support the routine use of plasma exchange in addition to standard remission-induction therapy in AAV. ANCA and other biomarkers can be helpful in association with clinical assessment to guide diagnosis and treatment decisions. Patients should be frequently evaluated during follow-up for possible disease relapses or treatment-related morbidity, and for monitoring damage accrual, especially metabolic and cardiovascular damage.

Environmental factors influencing the risk of ANCA-associated vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of diseases characterized by inflammation and destruction of small and medium-sized blood vessels. Clinical disease phenotypes include microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA). The incidence of AAV has been on the rise in recent years with advances in ANCA testing. The etiology and pathogenesis of AAV are multifactorial and influenced by both genetic and environmental factors, as well as innate and adaptive immune system responses. Multiple case reports have shown that sustained exposure to silica in an occupational environment resulted in a significantly increased risk of ANCA positivity. A meta-analysis involving six case-control studies showed that silica exposure was positively associated with AAV incidence. Additionally, exposure to air pollutants, such as carbon monoxide (CO), is a risk factor for AAV. AAV has seasonal trends. Studies have shown that various environmental factors stimulate the body to activate neutrophils and expose their own antigens, resulting in the release of proteases and neutrophil extracellular traps, which damage vascular endothelial cells. Additionally, the activation of complement replacement pathways may exacerbate vascular inflammation. However, the role of environmental factors in the etiology of AAV remains unclear and has received little attention. In this review, we summarized the recent literature on the study of environmental factors, such as seasons, air pollution, latitude, silica, and microbial infection, in AAV with the aim of exploring the relationship between environmental factors and AAV and possible mechanisms of action to provide a scientific basis for the prevention and treatment of AAV.

Cardiovascular disease and ANCA-associated vasculitis: are we missing a beat?

The association between cardiovascular (CV) disease and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is well documented. The recent work by Massicotte-Azarniouch et al. confirms the risk and adds to the existing evidence by describing the highest risk in the first 3 months after diagnosis. In this review, we aim to put their findings into perspective and formulate implications for the care of AAV patients. We discuss mechanisms for increased CV disease in AAV, including the impact of traditional risk factors and disease-related risks such as renal impairment and anti-myeloperoxidase (MPO) ANCA serotype. We also provide a brief primer on the impact of inflammatory-driven endothelial dysfunction and platelet activation on accelerated atherosclerosis in AAV patients. These features alongside the impact of disease activity and systemic inflammation provide potential explanations to why the incidence of CV events is highest in the first 3 months from diagnosis. We suggest future avenues of research, provide some suggestions to address and treat CV risk based on current evidence, and highlight the importance of addressing this topic early on. Addressing modifiable risk factors, dialogue with patients, patient information and a structured approach overall will be key to improve CV outcomes in AAV.

Serum PR3-ANCA Is a Predictor of Primary Nonresponse to Anti-TNF-α Agents in Patients with Ulcerative Colitis

Background

Anti-tumor necrosis factor-α (TNF-α) agents are effective for moderately to severely active ulcerative colitis (UC). Nonetheless, a proportion of patients fail to respond to these agents as therapy for induction of remission. Recent studies indicated that perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA) may predict response to anti-TNF-α agents in UC patients. However, whether PR3-ANCA can predict primary nonresponse (PNR) to anti-TNF-α agents has not yet been evaluated. The aim of this study was to examine whether PR3-ANCA can predict PNR to anti-TNF-α in UC patients.

Methods

This was a single-center retrospective study. Data were extracted from 50 patients with UC who had measurements of PR3-ANCA and received anti-TNF-α agents for the first time as induction therapy. The primary endpoint of this study was a proportion of patients with PNR stratified by PR3-ANCA positivity. PNR to anti-TNF-α agents was defined as failure to achieve reduction in partial Mayo score by 2 or more points and change to other therapeutics within 6 weeks.

Results

Fourteen (28%) of the 50 patients were PR3-ANCA positive. Seventeen (34%) of the 50 patients demonstrated PNR. Eleven (78.6%) of the 14 PR3-ANCA-positive patients demonstrated PNR, while 6 (16.7%) of the 36 PR3-ANCA-negative patients demonstrated PNR. Multivariate analysis demonstrated that PR3-ANCA positivity was associated with PNR to anti-TNF-α agents (odds ratio 19.29, 95% CI: 3.30-172.67; p = 0.002).

Conclusion

PR3-ANCA positivity can predict PNR to anti-TNF-α agents in UC patients.

Occupational Exposures and Smoking in Eosinophilic Granulomatosis With Polyangiitis: A Case-Control Study

OBJECTIVE

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Environmental agents and occupational exposures may confer susceptibility to EGPA, but data are scarce. This study was undertaken to investigate the association between occupational exposures (e.g., silica, farming, asbestos, and organic solvents) and other environmental agents (e.g., smoking) and the risk of EGPA.

METHODS

Patients with newly diagnosed EGPA (n = 111) and general population controls (n = 333) who were matched for age, sex, and geographic area of origin were recruited at a national referral center for EGPA. Exposures were assessed using a dedicated questionnaire administered by a specialist in occupational medicine, under blinded conditions. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated.

RESULTS

Exposures to silica (OR 2.79 [95% CI 1.55-5.01], P = 0.001), organic solvents (OR 3.19 [95% CI 1.91-5.34], P < 0.001), and farming (OR 2.71 [95% CI 1.71-4.29], P < 0.001) were associated with an increased risk of EGPA. Co-exposure to silica and farming yielded an OR of 9.12 (95% CI 3.06-27.19, P < 0.001), suggesting a multiplicative effect between these 2 exposures. Smoking (current and former smokers combined) was significantly less frequent among patients with EGPA compared to controls (OR 0.49 [95% CI 0.29-0.70], P < 0.001). The pack-year index was also lower among patients with EGPA (OR 0.96 [95% CI 0.94-0.98], P < 0.001). The association of silica and farming was primarily aligned with ANCA-positive EGPA, while the association of smoking status and organic solvents was primarily aligned with ANCA-negative EGPA.

CONCLUSION

The environment can influence susceptibility to EGPA. Exposure to silica, farming, or organic solvents is associated with an increased risk of EGPA, while smoking is associated with a lower risk. These exposures seem to have distinct effects on different EGPA subsets.

Predictors of renal outcomes in anti-neutrophil cytoplasmic antibody glomerulonephritis

Glomerulonephritis associated with anti-neutrophil cytoplasmic antibody (ANCA) vasculitis still has a high prevalence of end-stage renal disease (ESRD), particularly in patients with advanced renal failure at presentation. This study aims to evaluate the clinical and histo- pathological features of renal involvement and investigate factors associated with ESRD. Patients with renal biopsy-proven ANCA-associated glomerulonephritis were included retrospectively over a period of nine years (June 2007 to March 2016). The renal survival, defined as time to reach ESRD, was evaluated based on clinical parameters, histopathological classification, and renal risk score. A total of 37 patients with crescentic glomerulonephritis were included in the study. The average age was 54 ± 16 years (range: 17-80) and 51.3% were female. Twenty-two patients were diagnosed with microscopic polyangiitis and 15 had granulomatosis with polyangiitis. The median glomerular filtration rate at presentation was 16.73 mL/min/1.73 m². Thirty-five patients (94.5%) had renal failure at presentation and 23 patients (62.1%) required initial hemodialysis (HD) therapy. The pattern of glomerular injury was categorized as sclerotic in 48.6% of cases, crescentic in 24.3%, mixed in 24.3%, and focal class in 2.7%. Regarding renal risk score, we had five patients with low risk, 17 with intermediate risk and 15 with high risk. ESRD occurred in 47% of intermediate-risk group and 66% of the high risk group. During follow-up, 17 patients (45.9%) developed ESRD. Tobacco addiction (P = 0.02), alveolar hemorrhage (P = 0.04), hypertension (P = 0.04), initial HD (P = 0.04), and sclerotic class (P = 0.004) were associated with ESRD. In our patients, a sclerotic class was associated with a higher risk of ESRD, suggesting that histo- pathological classification is potentially an important parameter to predict outcomes in renal disease secondary to ANCA-associated vasculitis.

Environmental risk factors associated with ANCA associated vasculitis: A systematic mapping review

BACKGROUND

Anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) is a rare multi-system autoimmune disease, characterised by a pauci-immune necrotising small-vessel vasculitis, with a relapsing and remitting course. Like many autoimmune diseases, the exact aetiology of AAV, and the factors that influence relapse are unknown. Evidence suggests a complex interaction of polygenic genetic susceptibility, epigenetic influences and environmental triggers. This systematic mapping review focuses on the environmental risk factors associated with AAV. The aim was to identify gaps in the literature, thus informing further research.

METHODS

Articles that examined any environmental risk factor in AAV disease activity (new onset disease or relapse) were included. Studies had to make explicit reference to AAV, which includes the 3 clinico-pathological phenotypes (GPA, MPA and EGPA), rather than isolated ANCA-positivity. All articles identified were English-language, full manuscripts involving adult humans (>16 years). There was no restriction on publication date and all study designs, except single case reports, were included. The systematic search was performed on 9th December 2019, using the following databases: EMBASE, Medline (Ovid), Cochrane Library, CINAHL and Web of Science.

RESULTS

The search yielded a total of 2375 articles. 307 duplicates were removed, resulting in the title and abstract of 2068 articles for screening. Of these, 1809 were excluded. Thus, 259 remained for full-text review, of which 181 were excluded. 78 articles were included in this review. The most notable findings support the role of various pollutants - primarily silica and other environmental antigens released during natural disasters and through farming. Assorted geoepidemiological triggers were also identified including seasonality and latitude-dependent factors such as UV radiation. Finally, infection was tightly associated, but the exact microorganism(s) is not clear - Staphylococcus aureus is the most presently convincing.

CONCLUSION

The precise aetiology of AAV has yet to be elucidated. It is likely that different triggers, and the degree to which they influence disease activity, vary by subgroup (e.g. ANCA subtype, geographic region). There is a need for more interoperable disease registries to facilitate international collaboration and hence large-scale epidemiological studies, with novel analytical techniques.

Association of Cigarette Smoking With Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

IMPORTANCE

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic small vessel vasculitis characterized by circulating ANCAs targeting proteinase 3 (PR3) or myeloperoxidase (MPO) and associated with excess morbidity and mortality. Myeloperoxidase-ANCA-positive AAV and PR3-ANCA-positive AAV are increasingly recognized to have differences in genetic risk, pathogenesis, and response to treatment. Risk factors for AAV, including cigarette smoking, are poorly understood.

OBJECTIVE

To examine the association between cigarette smoking and AAV.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study included a consecutive inception cohort of 484 patients with AAV diagnosed from 2002 to 2017 compared with a cohort of sex-, race-, and age-matched controls. Eleven cases were excluded owing to discordant smoking information in the electronic health record. Controls were randomly selected from participants recruited to the Partners HealthCare Biobank between its inception in 2010 and 2018 and who completed a smoking questionnaire and were not diagnosed with AAV (n = 30 536).

EXPOSURES

Smoking status (current, former, never) and pack-years of cigarette smoking were determined from review of the electronic medical record and smoking questionnaires.

MAIN OUTCOMES AND MEASURES

Patients with AAV were individually matched with 3 randomly-selected controls based on sex, race, and age (within 2 years difference). Conditional logistic regression was performed to examine the association between cigarette smoking and AAV using odds ratios (OR) and 95% confidence intervals (CIs).

RESULTS

Overall, 473 cases were matched with 1419 controls (mean [SD] age, 59 [16] years; 281 women [59%], 396 white [84%]). Patients with AAV were more likely to be former (OR, 1.6; 95% CI, 1.3-2.0) or current smokers (OR, 2.7; 95% CI, 1.8-4.1); there was a dose-response relationship according to pack-years of exposure (P < .001). These associations were especially strong among participants with MPO-ANCA-positive disease (former smokers: OR, 1.7; 95% CI, 1.3-2.3; current smokers: OR, 3.5; 95% CI, 2.1-6.1) but not in participants with PR3-ANCA-positive AAV (former smokers: OR, 1.3; 95% CI, 0.9-2.0; current smokers: OR, 1.7; 95% CI, 0.8-3.5). After stratifying by selected demographics and disease manifestations, these associations remained strong.

CONCLUSIONS AND RELEVANCE

Cigarette smoking was associated with AAV, especially MPO-ANCA-positive AAV. Further studies are needed to investigate a potential pathogenic mechanism.

Smoking Is a Risk Factor for Relapse of Antimyeloperoxidase Antibodies-Associated Vasculitis

BACKGROUND/OBJECTIVE

Several studies have identified predictors of relapse in antineutrophil cytoplasmic antibody-associated small-vessel vasculitis. However, the role of smoking as a risk factor of relapse has not been elucidated. Therefore, this study aimed to evaluate whether a history of smoking is a dose-dependent independent risk factor for antineutrophil cytoplasmic antibody-associated small-vessel vasculitis relapse.

METHODS

This multicenter retrospective cohort study included 122 patients with granulomatosis with polyangiitis and microscopic polyangiitis (MPA) from 9 nephrology centers in Japan. Dose-response relationships between cigarette smoking and outcomes were assessed using multivariate Cox proportional hazards models, adjusted for clinically relevant factors. The primary outcome was the time from remission to first relapse.

RESULTS

During the observation period (median, 41 months; interquartile range, 23-66 months), 118 (95.8%) and 34 (21.7%) patients experienced at least 1 remission and 1 relapse, respectively. A log-rank test showed that smoking was significantly associated with relapse (p = 0.003). Multivariate Cox proportional hazards models found current smoking to be associated with relapse (adjusted hazard ratio, 7.48; 95% confidence interval, 2.73-21.0). An association between the risk of relapse and cumulative pack-years of smoking was also noted (p = 0.004). Smoking, however, was not associated with remission.

CONCLUSIONS

Smoking is a significant and dose-dependent risk factor for relapse of MPA. All patients with MPA who smoke should be encouraged to quit.

Cigarette smoking and risk of primary systemic vasculitis: a propensity score matching analysis

Introduction

Considering limited data about the association between smoking and primary systemic vasculitides (PSV), present study aims to investigate smoking habit in PSV patients compared to healthy subjects as well as to examine the effect of smoking on clinical characteristics, disease activity and disease outcome in PSV patients.

Methodology

We included 126 patients diagnosed with PSV and 210 age- and sex-matched healthy controls. Demographic and clinical information and smoking history of patients and healthy controls were obtained by direct interview and questionnaire. Individuals who had smoked at least 100 cigarettes in their lifetime before the first symptom of vasculitis were classified as smokers; those who had never smoked or smoked less than 100 cigarettes in their lifetime were categorized as never smokers. Disease activity was evaluated by Birmingham Vasculitis Activity Score (BVAS). Disease outcome was assessed by vasculitis damage index (VDI) and the number of patients with disease in remission. Propensity score matching analyses (PSM) for reducing the heterogeneity between studied groups and calculating the actual effect of smoking in PSV was performed.

Results

No significant differences were observed in clinical manifestations and disease outcome of patients including VDI and the patients with disease in remission between ever and never smokers. However, disease activity according to BVAS in ever smokers was significantly higher than never smokers (P=0.020). PSM resulted in 82 patients with PSV, and 164 matched healthy persons with similar baseline characteristics. By multivariate logistic regression and after adjustment for age, sex, marital status and educational status, ever smoking was not significantly associated with an increased risk of PSV compared with never smoking.

Discussion and conclusion

Our study indicated a significant association between disease activity and smoking as well as a non-significant association between the clinical manifestations and disease outcome of PSV with smoking in Azeri population. Although further studies are needed to confirm these preliminary results, it seems that smoking may not be a significant risk factor for PSV.

Novel insights into the aetiology of granulomatosis with polyangiitis-a case-control study using the Clinical Practice Research Datalink

Objectives

We aimed to provide insights into the aetiology of granulomatosis with polyangiitis (GPA), by conducting a large case-control study using a general population-based, prospectively collected database of healthcare records.

Methods

We compared all incident cases of GPA in the Clinical Practice Research Datalink 1990-2014, with up to 10 age-, sex- and general practice-matched controls. We identified potential risk factors, recorded numbers of cases and controls exposed to each, and calculated odds ratios (ORs) using conditional logistic regression. Our main analysis excluded data recorded during 1 year before diagnosis, to prevent early symptoms being mistaken for risk factors.

Results

We identified 757 people with GPA and matched 7546 controls. People with GPA were five times more likely to have a previous diagnosis of bronchiectasis (OR = 5.1, 95% CI: 2.7, 9.4; P < 0.0001), and these effects remained stable in diagnoses recorded >5 years prior to diagnosis. People with GPA were two to three times more likely than controls to have previous diagnoses of autoimmune diseases or chronic renal impairment, and these effects also remained stable >5 years prior to diagnosis. People with GPA were more likely to have a diagnosis of pulmonary fibrosis (OR = 5.7, 95% CI: 1.7, 19.5; P = 0.01) and sinus infections (OR = 2.7, 95% CI: 1.8, 4.2; P < 0.0001) recorded in the 3 years before diagnosis, but not before this. We also found former smoking, some medications and higher socio-economic status significantly, but less strongly, associated.

Conclusion

We found novel long-term associations between GPA and pre-existing bronchiectasis and autoimmune diseases.

Anti-neutrophil cytoplasmic antibody-associated vasculitis with renal involvement: Analysis of 89 cases

INTRODUCTION

The anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis with renal involvement are associated with high morbi-mortality. In this study we analyse if the prognosis of these diseases have improved in recent years, and which factors influence the outcomes.

MATERIAL AND METHODS

Retrospective single-centre observational study, which included all patients diagnosed with microscopic polyangiitis and granulomatosis with polyangiitis with renal involvement in the last 25 years. Demographic, clinical and biochemical parameters of prognostic interest were recorded. The differences between four chronological periods were analysed, along with the determinants of a poor outcome (death or end-stage renal disease).

RESULTS

Eighty-nine patients were included (mean age 64±15 years). Sixty-four patients (72%) had microscopic polyangiitis and 25 (28%) granulomatosis with polyangiitis. During the study period, 37 (42%) patients died. Through Cox regression analysis, the best determinants of mortality were the initial glomerular filtration rate (HR 0.911; P=.003), Charlson comorbidity index (HR 1.513; P<.0001) and tobacco smoking (HR 1.816; P=.003). 35% developed end-stage renal disease, and the best determinants (by competing-risk regression) were: initial glomerular filtration rate (sub-hazard ratio [SHR]: 0.791; P<.0001), proteinuria (SHR: 1.313; P<.0001), and smoking status (SHR: 1.848; P=.023). No differences were found in patients' mortality or renal survival between the different study periods.

CONCLUSIONS

Prognosis of anti-neutrophil cytoplasm antibodies vasculitis with renal involvement treated with conventional immunosuppressive therapy remains unsatisfactory, and continues to have increased long-term complications and mortality.

Antineutrophil Cytoplasmic Antibody-Positive Small-Vessel Vasculitis Associated with Antithyroid Drug Therapy: How Significant Is the Clinical Problem?

BACKGROUND

The aim of this review was to delineate the characteristics of antineutrophil cytoplasmic antibody (ANCA)-associated small-vessel vasculitis associated with antithyroid drugs (ATD). A PubMed search was made for English language articles using the search terms antithyroid drugs AND ANCA OR ANCA-associated vasculitis.

SUMMARY

The literature includes approximately 260 case reports of ANCA-associated small-vessel vasculitis related to ATD, with 75% of these associated with thiouracil derivatives (propylthiouracil [PTU]) and 25% with methyl-mercapto-imidazole derivatives (MMI/TMZ). The prevalence of ANCA-positive cases caused by ATD varied between 4% and 64% with PTU (median 30%), and 0% and 16% with MMI/TMZ (median 6%). Young age and the duration of ATD therapy were the main factors contributing to the emergence of ANCA positivity. Before ATD therapy initiation, the prevalence of ANCA-positive patients was 0-13%. During ATD administration, 20% of patients were found to be positive for ANCA. Only 15% of ANCA-positive patients treated with ATD exhibited clinical evidence of vasculitis, corresponding to 3% of all patients who received ATD. Clinical manifestations of ANCA-associated vasculitis related to ATD were extremely heterogeneous. When vasculitis occurred, ATD withdrawal was usually followed by rapid clinical improvement and a favorable prognosis.

CONCLUSIONS

ANCA screening is not systematically recommended for individuals on ATD therapy, particularly given the decreasing use of PTU in favor of TMZ/MMI. Particular attention should be given to the pediatric population with Graves' disease who receive ATD, as well as patients treated with thiouracil derivatives and those on long-term ATD therapy.

Classification, epidemiology and clinical subgrouping of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis

It is now 25 years since the first European studies on vasculitis--the anti-neutrophil cytoplasmic antibody (ANCA) standardization project. Over that period of time, there have been major developments in the classification of the vasculitides, which has permitted the conduct of high-quality epidemiology studies. Studying the epidemiology of rare diseases such as the ANCA-associated vasculitides (AAV) poses considerable challenges to epidemiologists. The first is the need for a clear definition of a case with good differentiation from similar disorders. The second is case capture. The vasculitides are rare, and therefore, a large population is required to determine the incidence and prevalence, and this poses questions of feasibility. A large population increases the risk of incomplete case detection but permits a reasonable number of cases to be collected in a practicable time frame, whereas a smaller population requires a much longer time frame to collect the necessary cases, which may also not be feasible. Statistical methods of capture-recapture analysis enable estimates to be made of the number of missing cases. The third is case ascertainment. The AAV are virtually always managed in secondary care, and therefore, hospital-based case ascertainment may be appropriate. Fourthly, the rarity of the conditions makes prospective case-control studies investigating risk factors difficult to conduct because the population size required to achieve statistical confidence is in excess of that which is readily available. Thus, much of the data on risk factors are derived from retrospective studies with inherent potential bias.

Pneumo-Renal Syndrome in Anti- Neutrophil Cytoplasm Antibody (ANCA)-Associated Small-Vessel Vasculitis

OBJECTIVES

We aimed to evaluate the prevalence of lung hemorrhage, its determinants and its prognostic significance in adults patients with severe kidney involvement due to ANCA-associated vasculitis diagnosed and treated in a nephrology department.

MATERIAL AND METHODS

Seventy-five patients consecutively diagnosed by kidney biopsy with crescentic pauci-immune glomerulonephritis entered this cohort study and were grouped according to the presence of diffuse alveolar hemorrhage (DAH - diagnosed as diffuse alveolar pattern on chest radiographs and anemia without evidence of another external bleeding). ANCAs were assessed by capture PR3-ANCA and MPO-ANCA ELISA or by indirect immunofluorescence.

OUTCOMES

Patients were followed for a median period of 38 (11.7; 65.8) months. The median age was 61.6 years. Median creatinine was 5.7 mg/dL and 17% of the patients needed temporary dialysis. Most of the patients (76%) had MPO-ANCA; 31% had pneumo-renal syndrome. DAH patients had more severe and active kidney disease, as reflected by higher serum creatinine (7.1 mg/dL vs 4.45 mg/dL; p=0.006) and higher hematuria (610/mm3 vs 230/mm3, p=0.003). The risk of DAH was not influenced by gender, age or ANCA specificity, but by smoking (smokers had a 4 (95%CI 1.18-14.2; p=0.002) times higher the risk of lung hemorrhage) and by season (patients diagnosed in winter and autumn had a 6 (95% CI 1.6-20.9; p=0.005) times higher the risk of lung hemorrhage). The proportion of responders and of patients with relapses, and time to maintenance dialysis or to death were similar irrespective to the occurrence of DAH at presentation.

CONCLUSION

In patients with ANCA associated pauci-immune glomerulonephritis, cold season, smoking and active kidney disease, but not ANCA specificity or inflammation were associated with lung hemorrhage. Although diffuse alveolar hemorrhage was the main cause of death, it was not related to short- or long-term outcome.

The association between silica exposure and development of ANCA-associated vasculitis: systematic review and meta-analysis

BACKGROUND

Crystalline silica is among the environmental exposures associated with increased risk of autoimmune diseases, including rheumatoid arthritis, systemic sclerosis and systemic lupus erythematosus. Silica exposure has also been related to the development of ANCA-associated vasculitides (AAV), but past studies appear to conflict as to the presence and magnitude of the associated risks of disease. We aimed to conduct a systematic review of the existing studies and meta-analysis of their results.

METHODS

We searched EMBASE, MEDLINE and international scientific conference abstract databases for studies examining the association of silica exposure with AAV. Studies in English, French, or Spanish were included and those examining the association of silica with ANCA-positivity alone were excluded. We assessed study quality using the Newcastle-Ottawa Scale. We meta-analyzed the results using random effects models and tested for heterogeneity. We performed sensitivity and subgroup analyses, examining studies that adjusted for smoking and occupational risk factors as well as studies that analyzed by subtypes of AAV.

RESULTS

We identified 158 potential manuscripts and 3 abstracts related to silica exposure and risk of AAV. 147 were excluded after abstract review and 14 underwent detailed evaluation of full manuscript/abstract. After further application of exclusion criteria, 6 studies (all cases-controls) remained. The studies had moderate heterogeneity in selection of cases and controls, exposure assessment, disease definition and controlling for potential confounders. We found an overall significant summary effect estimate of silica "ever exposure" with development of AAV (summary OR 2.56, 95% CI 1.51-4.36), with moderate heterogeneity (I(2)=48.40%). ORs were similar for studies examining only MPA (OR 3.95, CI 95% 1.89-8.24), compared to those only studying GPA (OR 3.56, CI 95% 1.85-6.82).

CONCLUSION

Despite moderate heterogeneity among studies, the totality of the evidence after meta-analysis points to an association between silica exposure and risk for developing AAV.

Association of cigarette smoking with organ damage in primary systemic vasculitis

OBJECTIVES

To study the association between late organ damage in patients with primary systemic vasculitis (PSV) and cigarette smoking. PSV included Wegener's granulomatosis (WG), microscopic polyangiitis (MPA), Churg-Strauss syndrome (CSS), and polyarteritis nodosa (PAN).

METHODS

The pattern and extent of organ damage according to the Vasculitis Damage Index (VDI) were analysed for 86 prevalent cases with PSV retrieved from a geographically defined population in southern Sweden (46 WG, 27 MPA, four CSS, and nine PAN). Data on clinical findings, laboratory tests, and smoking habits were collected from case records from the time of diagnosis. The patients were stratified into two main groups according to their smoking habits: smokers (subdivided into active and ex-smokers) and non-smokers (patients who had never smoked).

RESULTS

Data on smoking habits were available for 77 patients (90%). Thirty-three (38%) patients were categorized as smokers and 44 (51%) were non-smokers. Smoking was more common in men (61.5% vs. 23.6% in women, p = 0.001). There were no differences in smoking habits between the main diagnostic groups (WG 40% smokers, MPA 45%). Ear, nose, and throat (ENT) damage was significantly more prevalent in non-smokers (p = 0.001). Myocardial infarction (MI) and end-stage renal disease (ESRD) were more common in the current smokers (p = 0.04) than in the non-smokers.

CONCLUSIONS

We found ENT damage to be significantly less prevalent in smokers. This is the first report of a possible modifying effect of cigarette smoking on the development of organ damage in PSV, but more studies are needed before any firm conclusions can be made.

[Progress in pathogenesis and therapy of vasculitis syndrome]

Since antineutrophil cytoplasmic autoantibody (ANCA) was found, the researches in the pathogenesis of vasculitis syndrome have been developing. Proinflammatory cytokines including tumor necrosis factor-alpha are induced by certain infections, by which ANCA that binds to granule components of cytoplasm adhesions to endothelial cells. These endothelial cells produce proteolytic enzymes and oxygen radicals, which leads to vasculitis. It might be contributed in the production of ANCA that bacterial organisms are mimicry to the peptide sequences of granule components. The multicentric randomized clinical trials undertaken by the European Vasculitis Study Group (EUVAS) optimized that cyclophosphamide-corticosteroid combination therapy was useful to ANCA-associated vasculitis. It is increasing evidences that biologics are useful to ANCA-associated vasculitis, although it is necessary to take care of severe adverse effects.

Antineutrophil cytoplasmic autoantibody-associated small-vessel vasculitis

PURPOSE OF REVIEW

This review focuses on recent advances in the diagnosis, pathogenesis and treatment of antineutrophil cytoplasmic autoantibody-associated small-vessel vasculitis.

RECENT FINDINGS

Antineutrophil cytoplasmic autoantibodies are closely associated with Wegener's granulomatosis and microscopic polyangiitis. Within the Churg-Strauss syndrome, antineutrophil cytoplasmic autoantibodies, mostly directed towards myeloperoxidase, characterize patients with glomerulonephritis and small-vessel vasculitis. There is increasing evidence that myeloperoxidase-antineutrophil cytoplasmic autoantibodies are directly involved in the pathogenesis of necrotizing vasculitis. This is less clear for proteinase 3-antineutrophil cytoplasmic autoantibodies, markers for Wegener's granulomatosis. With respect to proteinase 3-antineutrophil cytoplasmic autoantibodies, complementary proteinase 3, a peptide translated from the antisense DNA strand of proteinase 3 and homologous to several microbial peptides, may be involved in induction of proteinase 3-antineutrophil cytoplasmic autoantibodies. Currently, various controlled trials have been initiated. Methotrexate has been shown to be effective for induction of remission in locoregional Wegener's granulomatosis. Other trials are underway.

SUMMARY

Apart from its diagnostic potential, antineutrophil cytoplasmic autoantibodies, particularly myeloperoxidase-antineutrophil cytoplasmic autoantibodies, are directly involved in the pathogenesis of the associated vasculitides. New treatment modalities, supposedly more efficacious and less toxic than daily oral cyclophosphamide, are being tested in randomized controlled trials.

What's new in the aetiopathogenesis of vasculitis?

The cause of the majority of childhood vasculitides is unknown although it is likely that a complex interaction between environmental factors and inherited host responses trigger the disease and determine the vasculitis phenotype. Epidemiological clues continue to implicate infectious triggers in Kawasaki syndrome (KS) and Henoch Schonlein purpura (HSP). Several genetic polymorphisms have now been described in KS and HSP which predispose to disease or predict disease severity. Anti-neutrophil cytoplasmic antibodies (ANCA) are now known to be directly involved in the pathogenesis of vascular injury in ANCA-associated vasculitides, although why some individuals develop ANCA in the first instance is not yet understood. Endothelial injury and repair are active areas of research in vasculitis. It is now possible to track endothelial injury non-invasively in children with vasculitis using surrogate markers of endothelial injury. The vasculogenic pathways involved in vascular repair following vasculitis, including endothelial progenitor cells, are beginning to be studied. It is anticipated that an improved understanding of the aetiopathogenesis of vasculitis in the young will ultimately shape future novel diagnostic and therapeutic approaches and will help us predict which children may develop premature arteriosclerosis in later life.

Anti-neutrophil cytoplasm-associated glomerulonephritis

Wegener's granulomatosis, microscopic polyangiitis, and renal limited vasculitis are associated with circulating anti-neutrophil cytoplasm antibodies and are an important cause of rapidly progressive glomerulonephritis. This review gives an account of recent advances in the understanding of the pathogenesis underlying these conditions and how these may lead to future treatments. Consideration is given to recent clinical trials in the management of anti-neutrophil cytoplasm antibodies (ANCA)-associated vasculitides.