Is granulomatosis with polyangiitis in Asia different from the West?

The incidence and clinical features of antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) have been shown to vary according to geographical areas, with granulomatosis with polyangiitis (GPA) being more common in northern Europe and microscopic polyangiitis (MPA) being more common in Asian countries. The annual incidence of GPA among Asians varies between 0.37/million to 2.1/million population. The prevalence of GPA has been estimated to be 1.94/100 000 in a Chinese population. Polymorphisms in class II major histocompatibility genes and ETS1 proto-oncogene has been shown in Asian patients with GPA. There is a difference in mean age at onset and proteinase 3 (PR3) or myeloperoxidase (MPO) positivity in GPA patients from different Asian countries. Those from India had mean age of 40 years and those from Japan had mean age of 65 years. Sixty percent of GPA patients from China and Japan were MPO ANCA positive while the majority of patients from India and Korea were PR3 positive. Geographical variation with lower frequency of renal involvement in Indian studies and higher frequency in Chinese patients has also been noted. Treatment outcomes have been similar to those reported from other parts of the world. Remission was achieved in about two-thirds of patients while relapses were noted in one-third to half of the patients. Apart from minor differences in the organ systems involved, MPO-ANCA GPA and PR3-ANCA GPA had similar rates of remission and relapses.

HLA-DPB1 variant rs3117242 is associated with anti-neutrophil cytoplasmic antibody-associated vasculitides in a Han Chinese population.

AIM: The vasculitis diseases granulomatosis with polyangiitis (GPA) and microscopic polyangitis (MPA) are the two major forms of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV). A recent genome-wide association study has shown that the genes HLA-DPB1 and HLA-DQ conferred susceptibility to GPA and MPA, respectively. We investigated the linkage between putative AAV-related genes (HLA-DPB1, ARHGAP18, CD226, CTLA-4, MOSPD2 and PRTN3) and AAV in a Han Chinese population. METHOD: A Sequenom MassAarray system (iPLEX assay, Sequenom, San Diego, CA, USA) was used to genotype single nucleotide polymorphisms (SNPs) in 176 Han Chinese patients with AAV (100 with GPA, 76 with MPA) and 485 ethnically matched healthy controls. RESULT: The frequency of the rs3117242 variant T allele (HLA-DPB1) was significantly higher in GPA patients than in the controls (68.0% compared with 50.4%, OR = 2.09, 95% CI: 1.51-2.88, Bonferroni corrected P-value [Pc] = 6.24E-5), but was not significantly different between MPA patients and controls (Pc = 0.14). The same results were obtained via genotype distribution and logistic regression analysis based on three genetic models. The allele and genotype distributions of the other polymorphisms were not significantly associated with AAV patients as a whole or GPA or MPA patients considered separately. CONCLUSION: The rs3117242 of HLA-DPB1 could be considered a genetic risk factor for GPA in Chinese Han people. These findings provide further insights and clues into the etiology of GPA and MPA.

Granulomatosis with polyangiitis according to geographic origin and ethnicity: clinical-biological presentation and outcome in a French population.

Objectives: Granulomatosis with polyangiitis (GPA) mainly affects white Europeans, but rarely GPA may also affect non-Europeans. This study aimed to describe GPA clinical-biological presentation and outcome in black sub-Saharan Africans and Afro-Caribbeans and in North Africans. Methods: Among 914 GPA patients included in the French Vasculitis Study Group database, geographic origin and ethnicity were known for 760. Clinical-biological presentations and outcomes of white Europeans vs black sub-Saharans and Afro-Caribbeans and vs North Africans were analysed. Results: Among the 760 patients, 689 (91%) were white Europeans, 33 (4.3%) were North Africans and 22 (2.9%) were sub-Saharans (n = 8) or Afro-Caribbeans (French West Indies, n = 14). Black sub-Saharans and Afro-Caribbeans, compared with white Europeans, were significantly younger at GPA diagnosis (P = 0.003), had more frequent central nervous system involvement (P = 0.02), subglottic stenosis (P = 0.002) and pachymeningitis (P = 0.009), and tended to have more frequent chondritis and retroorbital tumour. Median serum creatinine levels and Birmingham Vasculitis Activity Score were significantly lower in sub-Saharans and Afro-Caribbeans (P = 0.002 and P = 0.003, respectively). In contrast, in comparison with white Europeans, North Africans had only less frequent arthralgias (P = 0.004). Time to relapse was shorter for black sub-Saharans and Afro-Caribbeans compared with white Europeans [adjusted HR = 1.96 (95% CI: 1.09, 3.51) (P = 0.02)], and did not differ for North Africans. In contrast, overall survival was not significantly different according to ethnicity. Conclusion: Our findings indicated different GPA clinical presentations in white Europeans and sub-Saharans and Afro-Caribbeans, with black patients having more frequent severe granulomatous manifestations. In addition, time to relapse was significantly shorter for black sub-Saharans and Afro-Caribbeans compared with white Europeans.

The incidence, prevalence and mortality of granulomatosis with polyangiitis in the UK Clinical Practice Research Datalink.

Objective: To estimate the incidence, prevalence and mortality of granulomatosis with polyangiitis in the UK. Methods: We conducted a historical cohort study using data from the Clinical Practice Research Datalink and Hospital Episode Statistics (HES). We calculated incidence rate ratios, adjusted for age, gender and ethnicity, using Poisson regression. Results: We identified 462 cases diagnosed between 1997 and 2013. Our overall estimate of incidence was 11.8 (95% CI: 10.7, 12.9)/million person-years. The incidence was 0.88 (95% CI: 0.40, 1.96) in children (aged <16 years) and 14.0 (95% CI: 12.8, 15.4) in adults. The incidence was lower in females (adjusted incidence rate ratio = 0.68; 95% CI: 0.56, 0.81) and highest in the 55-69 year age group (adjusted incidence rate ratio = 6.8, 95% CI: 4.9, 9.6; reference group 16-39 years). The incidence was not significantly different in the Black/Minority Ethnic population from that in the White population (adjusted odds ratio = 0.78, 95% CI: 0.53, 1.13, P = 0.13). The prevalence in 2013 was 134.9 (95% CI: 121.3, 149.6)/million. Mortality was 13.6% at 1-year, and higher in the HES- than in the Clinical Practice Research Datalink-identified cases (hazard ratio = 3.16, 95% CI: 2.19, 4.56, P < 0.001). Conclusion: By combining primary and secondary care datasets, we have found the incidence and mortality of granulomatosis with polyangiitis to be higher than previously reported. We predict that at present each year in the UK there will be ∼700 new cases, of whom 95 will die within 12 months.

ANCA-associated vasculitis in Hispanic Americans: an unrecognized severity.

This study aims to compare the severity and outcomes of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) between Hispanics and Caucasians living in the same geographical area. All patients diagnosed with AAV at two academic institutions in Chicago from January 2006 to December 2012 were retrospectively and prospectively identified. Disease activity was measured with the Birmingham Vasculitis Activity Score (BVAS), and disease damage was measured with the Vasculitis Damage Index (VDI). Student's t test and chi-square tests were employed; p ≤ 0.05 was considered significant. Seventy patients with AAV were identified; 15 patients were excluded. Fifty-five patients were included in the study: 23 Hispanics and 32 Caucasians, 35 patients with granulomatosis with polyangiitis (Wegener's), 12 with microscopic polyangiitis, 7 with eosinophilic granulomatosis with polyangiitis, and 1 with renal-limited vasculitis. Compared to Caucasians, Hispanics had a higher BVAS at presentation (16.3 ± 7.6 versus 10.7 ± 7.5, p = 0.006), a higher VDI at presentation (2.90 ± 1.50 versus 2.06 ± 1.30, p = 0.030), and a cumulative VDI (3.90 ± 1.70 versus 2.50 ± 1.90, p = 0.010). Renal involvement was more common among Hispanics (85 % of Hispanics versus 48 % of Caucasians, p = 0.01). Seventy percent of Hispanics had acute renal failure (mean creatinine = 3.37 ± 4.4 mg/dl) of whom seven (50 %) required dialysis, versus 25 % of Caucasians (mean creatinine = 1.78 ± 1.57 mg/dl, p = 0.03) and only two requiring dialysis. Compared to Caucasians, Hispanics with AAV present with more severe disease and higher damage indices. Larger studies are required to confirm these findings and delineate the respective roles of environment and genetics in the pathogenesis of the disease.

Incidence of granulomatosis with polyangiitis (Wegener's) in Greenland and the Faroe Islands: epidemiology of an ANCA-associated vasculitic syndrome in two ethnically distinct populations in the North Atlantic area.

OBJECTIVES: Previous studies suggest that the incidence of granulomatosis with polyangiitis (Wegener's; GPA) increases along a south-north gradient in the Northern Hemisphere with an incidence of 8.0/million/year reported for the population of Northern Norway. In the present study, we assessed the incidence of GPA in the predominantly Inuit population of Greenland and in the Caucasian population of the Faroe Islands. METHODS: Greenlandic and Faroese patients affected by severe rheumatic diseases are routinely referred to the National University Hospital in Denmark for treatment. By means of the Danish National Hospital register, we identified all Greenlandic and Faroese patients treated at the hospital under a diagnosis of GPA during 1992-2011. For each patient, the GPA diagnosis was validated by medical files review. RESULTS: One patient born and living in Greenland and 6 from the Faroe Islands were identified. The incidence of GPA was 1.0/million/year (95% CI 0.02-5.6) in Greenland and 6.4/million/year (95% 2.4-14.0) in the Faroe Islands. During the period of study, no cases of GPA occurred among Greenlanders aged 0-44 years, while an incidence of 4.1/million/year (95% CI: 0.1-22.9) was calculated for those aged ≥45 years. In the Faroese population, incidences of 1.7/million/year (95% CI 0.4-9.4) and 14.8/million/year (95% CI 4.8-34.6) were calculated for the age-groups 0-44 and ≥45 years, respectively. CONCLUSIONS: The occurrence of GPA is lower among Inuit in Greenland than among Caucasians living in the Faroe Islands. This observation demonstrates that the risk of GPA varies across ethnic groups populating the northernmost regions of the world.

DRB1*15 allele is a risk factor for PR3-ANCA disease in African Americans.

Anti-neutrophil cytoplasmic autoantibody (ANCA) disease rarely occurs in African Americans and risk factors for the disease in this population are unknown. Here, we genotyped MHC class II alleles and found that, among African Americans, those with proteinase 3-ANCA (PR3-ANCA) had 73.3-fold higher odds of having HLA-DRB1*15 alleles than community-based controls (OR 73.3; 95% CI 9.1 to 591). In addition, a disproportionate number of African American patients carried the DRB1*1501 allelic variant of Caucasian descent rather than the DRB1*1503 allelic variant of African descent. Among Caucasians, those with PR3-ANCA had 2.2-fold higher odds of carrying DRB1*1501 than controls (OR 2.2; 95% CI 1.2 to 4.0). A validation study supported by the Vasculitis Clinical Research Consortium confirmed the strong association between the DRB1*15 allele and PR3-ANCA disease, among African Americans. Furthermore, we found that DRB1*1501 protein binds with high affinity to amino acid sequences of sense-PR3, purportedly an antigenic epitope, and to the amino acid sequence complementary to this epitope in vitro. Peptides of sense-PR3 and complementary-PR3 also bound to TNF-α-induced surface expression of DRB1*1501 on peripheral neutrophils. Taken together, these data suggest HLA-DRB1*15 alleles contribute to the pathogenesis of PR3-ANCA disease.

Wegener's granulomatosis in Finland in 1981-2000: risk of dialysis-dependent renal disease.

OBJECTIVE: To determine the risk of renal insufficiency requiring transient or chronic dialysis and its contributing factors in patients diagnosed with Wegener's granulomatosis (WG) between 1981 and 2000 in Finland. PATIENTS AND METHODS: A retrospective cohort study using hospital discharge registers with a review of hospital case reports. Data were complemented with files from the Finnish Registry for Kidney Diseases. All files were reviewed by 8 October 2005. RESULTS: A total of 492 patients received a verified diagnosis of WG in 1981-2000. Of these, 84 (17%) needed dialysis by the end of follow-up. Of the 84 dialysed patients, 32 (38%) recovered initially, 32 (38%) needed chronic dialysis (dialysed > 3 months), and 19 (23%) received a kidney transplant. Forty-one (49%) of the dialysed patients were alive at the end of follow-up: 16 with a kidney transplant, 14 on dialysis, and 11 without dialysis. The cumulative rate of developing renal involvement leading to dialysis was 14.6% [95% confidence interval (CI) 11.6-18.2] at 5 years and 29.6% (95% CI 21.5-40.0) at 20 years after onset of WG symptoms. Elevated creatinine levels at presentation were associated with an increased rate of renal insufficiency requiring chronic dialysis. Age, gender, and involvement of any particular organ system had no significant effect. CONCLUSIONS: WG patients are at great risk of developing renal insufficiency, and this risk increases as the disease progresses. Elevated creatinine levels at presentation are associated with an increased risk of dialysis-dependent end-stage renal disease.

Alpha1-antitrypsin deficiency-related alleles Z and S and the risk of Wegener's granulomatosis.

OBJECTIVE: Deficiency of α(1) -antitrypsin (α(1) AT) may be a determinant of susceptibility to Wegener's granulomatosis (WG). Several previous, mainly small, case-control studies have shown that 5-27% of patients with WG carried the α(1) AT deficiency Z allele. It is not clear whether the S allele, the other major α(1) AT deficiency variant, is associated with WG. This study investigated the relationship of the α(1) AT deficiency Z and S alleles with the risk of developing WG in a large cohort. METHODS: We studied the distribution of the α(1) AT deficiency alleles Z and S in 433 unrelated Caucasian patients with WG and 421 ethnically matched controls. Genotyping was performed using an allele discrimination assay. Results were compared between cases and controls using exact statistical methods. RESULTS: Among the patients with WG, the allele carriage frequencies of Z and S were 7.4% and 11.5%, respectively. The frequencies of the 6 possible genotypes differed in a statistically significant manner between cases and controls (P = 0.01). The general genetic 2-parameter codominant model provided the best fit to the data. Compared with the normal MM genotype, the odds ratio (OR) for MZ or MS genotypes was 1.47 (95% confidence interval [95% CI] 0.98-2.22), and the OR for ZZ, SS, or SZ genotypes was 14.58 (95% CI 2.33-∞). ORs of similar direction and magnitude were observed within the restricted cohorts that excluded cases and controls carrying ≥1 Z or ≥1 S allele. CONCLUSION: Both Z and S alleles display associations with risk of WG in a codominant genetic pattern. These findings strengthen the evidence of a causal link between α(1) AT deficiency and susceptibility to WG.

Familial associations of rheumatoid arthritis with autoimmune diseases and related conditions.

OBJECTIVE: In the era of genome-wide association studies, familial risks are used to estimate disease heritability and the likelihood of candidate-gene identification. This study was undertaken to estimate associations of rheumatoid arthritis (RA) with any of 33 autoimmune diseases and related conditions among parents and offspring, singleton siblings, twins, and spouses. METHODS: The Multigeneration Register in Sweden was used as a reliable source of information on Swedish families throughout the last century. Data on autoimmune diseases in individual family members were obtained through linkage to the Hospital Discharge Register. The standardized incidence ratio (SIR) was calculated as a measure of the relative risk of RA in family members of patients with RA or any of 33 other autoimmune diseases or related conditions, as compared with the relative risk of RA in those lacking an affected family member. RESULTS: Among a total of 447,704 patients, 47,361 were diagnosed as having RA. The SIRs for RA were 3.02 in offspring of affected parents, 4.64 in siblings, 9.31 in multiplex families, 6.48 in twins, and 1.17 in spouses. Significant associations with the familial risk of RA in offspring according to parental proband were observed for ankylosing spondylitis (SIR 2.96), localized scleroderma (SIR 2.40), Sjögren's syndrome (SIR 2.25), systemic lupus erythematosus (SIR 2.13), systemic sclerosis (SIR 1.65), Hashimoto thyroiditis/hypothyroidism (SIR 1.54), pernicious anemia (SIR 1.53), sarcoidosis (SIR 1.40), psoriasis (SIR 1.36), Wegener's granulomatosis (SIR 1.34), and asthma or polymyalgia rheumatica (SIR 1.32). CONCLUSION: This is the first study to compare the familial risks of RA in relation to a large number of autoimmune diseases and related conditions using data from a single population. The high discordant familial risks in this population suggest that there is extensive genetic sharing between RA and the associated diseases.

A comparative study of the diagnostic accuracy of ELISA systems for the detection of anti-neutrophil cytoplasm antibodies available in Japan and Europe.

OBJECTIVES: Primary systemic vasculitis associated with anti-neutrophil cytoplasm antibodies (ANCA) differs in its frequency and clinical expression between Japan and Europe. We sought to ascertain whether such differences arise from the performance of enzyme-linked immunosorbent assays (ELISAs) for ANCA. METHODS: Plasma samples from 64 consecutive Japanese patients with a clinical and histological diagnosis of primary systemic vasculitis including microscopic polyangiitis (MPA; n=52), Churg-Strauss syndrome (CSS; n=1), and Wegener's granulomatosis (WG; n=11), or those from disease controls with non-vasculitic glomerulonephritis (n=54) and healthy controls (n=55) were tested for the presence of myeloperoxidase (MPO) by ELISAs available in Japan (Nipro and MBL) and compared with those in Europe (Wieslab). The sensitivity and specificity were calculated for each ELISA, and its diagnostic performance was assessed by receiver operating characteristic curve analysis. RESULTS: The sensitivity and specificity of either MPO-ANCA assays for a diagnosis of MPA were 90.4% and 98.2% (Nipro), 88.2% and 96.3% (MBL), and 86.5% and 99.1% (Wieslab). The overall diagnostic performance, assessed as the area under curve of the MPO-ANCA ELISAs for MPA were 0.946+/-0.022 (Nipro), 0.970+/-0.017 (MBL), and 0.971+/-0.017 (Wieslab), while that of PR3-ANCA ELISAs for WG were 0.986+/-0.025 (Nipro), 0.993+/-0.017 (MBL), and 0.916+/-0.059 (Wieslab). CONCLUSIONS: The MPO-ANCA ELISAs commercially available in Japan exhibited high sensitivity and specificity for the diagnosis of ANCA-associated vasculitides and provided similar diagnostic value to those in Europe. These results facilitate further international comparison of ANCA-associated vasculitides between Japanese and European populations.

Epidemiology of Wegener's granulomatosis: Lessons from descriptive studies and analyses of genetic and environmental risk determinants.

During the past 15 years, the epidemiology of Wegener's granulomatosis (WG) has become better understood. Descriptive epidemiological studies carried out primarily in European countries estimate a prevalence of WG ranging from 24 to 157 per million and annual incidence rates from 3 to 14 per million. These studies suggest a North-South declining gradient in disease risk in the Northern Hemisphere and an increase in incidence over time, although the latter is likely largely due to improved diagnostic ascertainment. Data also indicate the presence of potential secular and seasonal variations in WG incidence and a decreasing disease risk among non-Caucasians. Furthermore, analytic epidemiological studies have pointed out putative genetic and non-genetic risk factors for WG. Genetic investigations have identified various candidate genes, with alpha1-antitrypsin deficiency being the most consistently reported genetic susceptibility factor to date. Even though much less research has been devoted to environmental risk factors, evidence has grown for a possible relationship between WG and occupational exposure to crystalline silica. Thus far, data support the concept of WG as a multifactorial disease in which genetic and environmental determinants are involved but a major gap in understanding persists regarding the extent to which both factors contribute to its development. This and many other questions remain to be answered by future structured epidemiological research. This review focuses on the current knowledge of descriptive epidemiology and genetic and environmental factors associated with WG.

Characteristics of Chinese patients with Wegener's granulomatosis with anti-myeloperoxidase autoantibodies.

BACKGROUND: Cytoplasmic antineutrophil cytoplasmic autoantibodies (cANCA)/proteinase-3(PR3)-ANCA was considered the serologic diagnostic marker for Wegener's granulomatosis (WG). However, Chinese patients with MPO-ANCA positive WG were frequently diagnosed. We now analyze the characteristics of patients with MPO-ANCA positive WG and investigate the difference between patients with MPO-ANCA and PR3-ANCA. METHODS: Patients with WG were selected according to both Chapel Hill Consensus Conference definition and American College of Rheumatology (ACR) classification criteria in 500 Chinese patients with ANCA-associated systemic vasculitides. The clinical manifestions were compared between patients with MPO-ANCA and with PR3-ANCA. RESULTS: Eight-nine patients fulfilled the diagnostic criteria of WG: 54/89(60.7%) were MPO-ANCA positive, 34/89(38.2%) were PR3-ANCA positive. Patients with MPO-ANCA were predominantly female compared with patients with PR3-ANCA. Patients with MPO-ANCA also had multisystem involvement. However, the prevalences of arthagia, skin rash, ophthalmic and ear involvement were significantly lower in patients with MPO-ANCA than those in patients with PR3-ANCA (46.3% vs. 70.6%, P < 0.05; 20.4% vs. 44.1%, P < 0.05; 27.8% vs. 58.8%, P < 0.01; 40.7% vs. 67.6%, P < 0.05, respectively). The prevalence of elevated initial serum creatinine was significantly higher in patients with MPO-ANCA than that in patients with PR3-ANCA (81.5% vs. 61.8%, chi(2) = 4.20, P < 0.05). CONCLUSION: Patients with MPO-ANCA positive WG were not rare in Chinese.