Familial occurrence of systemic vasculitis and rapidly progressive glomerulonephritis

Familial Eosinophilic Granulomatosis with Polyangiitis in a Sister and Brother

Eosinophilic granulomatosis with polyangiitis (EGPA) is a vasculitis characterized by an abnormally high number of eosinophils in the peripheral blood and tissues. EGPA is an extremely rare disorder, with an incidence of 0.5 to 3.7 new cases per million people per year and an overall prevalence of 2.4 to 14 per million adults. There is little knowledge about the genetic factors that influence this disease. There are only two reports of familial EGPA: one in Japan and one in Turkey. We herein report a third case of familial EGPA in a brother and sister who were negative for myeloperoxidase-antineutrophil cytoplasmic antibodies.

Familial eosinophilic granulomatosis with polyangiitis in a mother and daughter

A 17-year-old girl was admitted to our unit with weight loss, dyspnoea, arthralgia and sinusitis. Her medical history was noteworthy for bronchial asthma and she required systemic steroid therapy. Her mother had a history of eosinophilic granulomatosis with polyangiitis (EGPA). Laboratory tests revealed excessive eosinophilia and elevated erythrocyte sedimentation. The assay for peripheral antineutrophil cytoplasmic antibodies was negative. Histopathological examination of lung biopsy revealed EGPA. The patient was treated with methylpredinosolone; her eosinophil count normalised and she began to improve clinically and radiographically. There is no genetic factor to influence susceptibility to this disease. To the best of our knowledge, this is the second report of familial EGPA disease in the literature, with a mother and daughter both being affected. EGPA disease should be kept in mind in a patient with uncontrolled asthma and eosinophilia with a positive family history for EGPA.

Association of granulomatosis with polyangiitis (Wegener's) with HLA-DPB1*04 and SEMA6A gene variants: evidence from genome-wide analysis

OBJECTIVE

To identify genetic determinants of granulomatosis with polyangiitis (Wegener's) (GPA).

METHODS

We carried out a genome-wide association study (GWAS) of 492 GPA cases and 1,506 healthy controls (white subjects of European descent), followed by replication analysis of the most strongly associated signals in an independent cohort of 528 GPA cases and 1,228 controls.

RESULTS

Genome-wide significant associations were identified in 32 single-nucleotide polymorphic (SNP) markers across the HLA region, the majority of which were located in the HLA-DPB1 and HLA-DPA1 genes encoding the class II major histocompatibility complex (MHC) DPβ chain 1 and DPα chain 1 proteins, respectively. Peak association signals in these 2 genes, emanating from SNPs rs9277554 (for DPβ chain 1) and rs9277341 (DPα chain 1) were strongly replicated in an independent cohort (in the combined analysis of the initial cohort and the replication cohort, P = 1.92 × 10(-50) and 2.18 × 10(-39) , respectively). Imputation of classic HLA alleles and conditional analyses revealed that the SNP association signal was fully accounted for by the classic HLA-DPB1*04 allele. An independent single SNP, rs26595, near SEMA6A (the gene for semaphorin 6A) on chromosome 5, was also associated with GPA, reaching genome-wide significance in a combined analysis of the GWAS and replication cohorts (P = 2.09 × 10(-8) ).

CONCLUSION

We identified the SEMA6A and HLA-DP loci as significant contributors to risk for GPA, with the HLA-DPB1*04 allele almost completely accounting for the MHC association. These two associations confirm the critical role of immunogenetic factors in the development of GPA.

Genetically determined severity of anti-myeloperoxidase glomerulonephritis

Myeloperoxidase (MPO) is a target antigen for antineutrophil cytoplasmic autoantibodies (ANCA). There is evidence that MPO-ANCA cause necrotizing and crescentic glomerulonephritis (NCGN) and vasculitis. NCGN severity varies among patients with ANCA disease, and genetic factors influence disease severity. The role of genetics in MPO-ANCA NCGN severity was investigated using 13 inbred mouse strains, F1 and F2 hybrids, bone marrow chimeras, and neutrophil function assays. Mouse strains include founders of the Collaborative Cross. Intravenous injection of anti-MPO IgG induced glomerular crescents in >60% of glomeruli in 129S6/SvEv and CAST/EiJ mice, but <1% in A/J, DBA/1J, DBA/2J, NOD/LtJ, and PWK/PhJ mice. C57BL6J, 129S1/SvImJ, LP/J, WSB/EiJ, NZO/HILtJ, and C3H mice had intermediate severity. High-density genotypes at 542,190 single nucleotide polymorphisms were used to identify candidate loci for disease severity by identifying genomic regions that are different between 129S6/SvEv and 129S1/SvImJ mice, which are genetically similar but phenotypically distinct. C57BL/6 × 129S6 F2 mice were genotyped at 76 SNPs to capture quantitative trait loci for disease severity. The absence of a dominant quantitative trait locus suggests that differences in severity are the result of multiple gene interactions. In vivo studies using bone marrow chimeric mice and in vitro studies of neutrophil activation by anti-MPO IgG indicated that severity of NCGN is mediated by genetically determined differences in the function of neutrophils.

Association of HLA genes with clinical outcomes of ANCA-associated vasculitis

BACKGROUND AND OBJECTIVES

The HLA system plays a central role in the distinction between self antigens and non-self antigens. This study aimed to investigate the association between HLA genes and the outcomes of patients with ANCA-associated vasculitis (AAV).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study recruited 152 consecutive Chinese patients with AAV. The predictive value of the HLA alleles for renal outcome, response to treatment, and all-cause mortality were analyzed.

RESULTS

The proportion of patients with treatment failure was significantly higher in DRB1*0405-positive patients than in DRB1*0405-negative patients (41.7% versus 12.9%; P=0.008; corrected P=0.02). After adjusting for the other potential predictors, DRB1*0405 was still an independent predictor for the poor response to treatment (hazard ratio [HR], 5.91; 95% confidence interval [95% CI], 1.23-28.52; P=0.03). Renal survival was significantly worse in patients with DRB1*0405 than those without DRB1*0405 (P<0.001; corrected P<0.001). After adjusting for the other potential predictors, DRB1*0405 was still an independent predictor for ESRD (HR, 5.50; 95% CI, 2.18-13.88; P<0.001). The probability of all-cause mortality in patients with DPB1*0402 was significantly higher than those without DPB1*0402 (P=0.02; corrected P=0.04). After adjusting for the other potential predictors, DPB1*0402 was still an independent predictor for all-cause mortality (HR, 2.52; 95% CI, 1.21-5.28; P=0.01).

CONCLUSIONS

In AAV patients, DRB1*0405 might be an independent risk factor for the poor response to treatment and the deterioration of renal function, whereas DPB1*0402 might be an independent risk factor for all-cause mortality.

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.

Familial clusters of ANCA small-vessel vasculitis

Small-vessel vasculitides associated with the presence of antineutrophil cytoplasmic antibodies in the serum are characterized by inflammation and necrosis of small vessels. A pauci-immune necrotizing crescentic glomerulonephritis typically occurs when there is renal damage. Pathogenesis of these diseases remains unclear although infectious, genetic and environmental factors have been involved. Few familial clusters of antineutrophil cytoplasmic antibodies' small-vessel vasculitis are described in the literature. We report two families with first-degree relatives affected with antineutrophil cytoplasmic antibodies' small-vessel vasculitis.

Risks and relative risks of Wegener's granulomatosis among close relatives of patients with the disease

OBJECTIVE

The etiology of Wegener's granulomatosis (WG) supposedly involves interplay between genetic susceptibility and environmental triggers. However, little is known about whether WG actually clusters in families. Information on the degree of familial aggregation in WG is of clinical relevance, because patients with WG often want to know whether their diagnosis puts their closest relatives at increased risk of the disease. The aim of this study was to investigate the risk of WG in relatives of patients with WG.

METHODS

Using Swedish nationwide registers on morbidity, family structure, and vital status, we compared the occurrence of WG (register-based plus chart review) among 6,670 first-degree relatives and 428 spouses of 1,944 Swedish patients with WG with the occurrence among 68,994 first-degree relatives and 4,812 spouses of 19,655 control subjects from the general population. Relative risks were estimated using the Cox proportional hazards regression model.

RESULTS

Two of the 6,670 first-degree relatives of patients with WG and 13 of the 68,994 first-degree relatives of their population controls had WG, resulting in a relative risk of 1.56 (95% confidence interval 0.35-6.90). None of the 428 spouses of patients had WG.

CONCLUSION

In absolute terms, the occurrence of WG among close biologic and nonbiologic relatives of patients with WG is low. In terms of relative risk, our results provide strong evidence against a pronounced increase in familial risk such as that noted for systemic lupus erythematosus, irritable bowel disease, and multiple sclerosis but are compatible with familial aggregation of a magnitude similar to that for rheumatoid arthritis.

Hypotheses on the etiology of antineutrophil cytoplasmic autoantibody associated vasculitis: the cause is hidden, but the result is known

The first description of what is now known as antineutrophil cytoplasmic autoantibody-associated necrotizing vasculitis appeared more than 140 yr ago. Since then, many aspects of the pathogenic pathway have been elucidated, indicating the involvement of antineutrophil cytoplasmic autoantibodies, but why antineutrophil cytoplasmic autoantibodies are produced in the first place remains unknown. Over the years, many hypotheses have emerged addressing the etiology of antineutrophil cytoplasmic antibody production, but no exclusive factor or set of factors can so far be held responsible. Herein is reviewed the most influential hypotheses regarding the causes of antineutrophil cytoplasmic antibody-associated vasculitis with the aim of placing in an epidemiologic background the different hypotheses that are centered on environmental and genetic influences.

Genetic basis of murine lupus nephritis

Systemic lupus erythematosus is a generalized autoimmune disease affecting multiple end-organs including the kidneys. Glomerulonephritis is a leading cause of death in lupus, both in patients and murine models that develop disease spontaneously. Genetic mapping studies have uncovered several genetic intervals that confer susceptibility to nephritis both in human beings and in mice. This review surveys the genomic positions of these nephritis susceptibility loci in murine lupus. Currently we know very little about the molecular identities of the culprit genes within these mapped loci and whether these genetic elements contribute to nephritis directly in a renal-intrinsic fashion or indirectly by augmenting the formation of pathogenic autoantibodies. The next decade is likely to witness a significant broadening of our understanding of how different genes and molecules might facilitate end-organ damage in lupus.

Familial Churg-Strauss syndrome in two sisters

Churg-Strauss syndrome (CSS) is an uncommon systemic vasculitis with an increase in the number of eosinophils in the peripheral blood and tissues. Its pathogenesis is unknown, and there is no evidence that genetic factors influence susceptibility to this disease. We present a case of familial CSS in two sisters with atopic-type bronchial asthma and negative perinuclear anti-neutrophil cytoplasmic antibody results. We investigated the human leukocyte antigen typing of the sisters and their six living siblings but found no evidence for heritability of CSS. To our knowledge, this is the first report of familial CSS.

Major histocompatibility complex HLA region largely explains the genetic variance exercised on neutrophil membrane proteinase 3 expression

ANCA-associated vasculitides, a common cause of rapidly progressive glomerulonephritis, are influenced by genetic variance. Neutrophil membrane expression of the ANCA antigen proteinase 3 (PR3) is pathogenically important. A subset of membrane PR3-positive neutrophils can be distinguished from a membrane-negative subset in any given subject. The percentage of membrane PR3-positive neutrophils is genetically determined. In this study, 17 pairs of HLA-matched siblings were typed for their percentage of membrane PR3-positive neutrophils. The HLA-matched siblings showed a high concordance (r = 0.67, P < 0.05), similar to that seen in monozygotic twins. For testing of whether the HLA system influences membrane PR3 percentage, membrane PR3 typing and HLA typing of 51 unrelated patients with Wegener's granulomatosis and 49 normal control subjects was performed. Using two independent statistical methods, a group of 34 HLA antigens was found to predict a large fraction of the membrane PR3 phenotype in patients and control subjects. Certain major histocompatibility HLA antigens have been implicated to conflicting degrees in ANCA-associated vasculitides. However, in earlier studies, the contribution of the HLA system to the genetic variance of the disease was unclear. In this cohort, found was an association of Wegener's granulomatosis with the same group of HLA antigens that predicted for membrane PR3 percentage and a similar correlation with clinical parameters at initial presentation. The disease status in 80% of the patients and 82% of the control subjects could be predicted correctly on the basis of HLA typing by discriminate function analysis (P < 0.001). After removal of the predicted individual from the sample, this association remained significant (64 and 63% correct prediction; P < 0.001). The data suggest that a complex interaction of the entire HLA system is responsible for the genetic influence on membrane PR3 percentage and Wegener's granulomatosis.

Anti-Neutrophil Cytoplasmic Autoantibodies: A Renewed Paradigm in Periodontal Disease Pathogenesis?

In the past, various models including the autoimmunity model have been proposed to explain the pathogenesis of periodontal diseases. The aim of this review is to introduce the pathogenic role of anti-neutrophil cytoplasmic autoantibodies (ANCAs) in various autoimmune diseases and compare these conditions with periodontal disease to elucidate common pathogenic mechanisms. Also, a novel model to explain the pathogenesis of periodontal disease based on the concept of ANCA-associated autoimmunity is proposed. This encompasses a wide array of biochemical mediators that range from direct and indirect initiators of ANCA production and eventual release of proinflammatory mediators and free radicals, all of which have been implicated in periodontal tissue destruction in the past. In addition, specific links between the typical ANCA-associated diseases and periodontal disease are discussed. Finally, a new paradigm in the periodontal disease-associated destruction is proposed that includes the currently accepted mechanism, namely, the genetic-microbial-host interactions.

Pathogénie des vascularites systémiques primitives (I) : vascularites ANCA-positives

The pathogenesis of different types of systemic vasculitis positive for antineutrophil cytoplasmic antibodies (ANCA) remains incompletely understood. ANCA constitute a heterogeneous group of antibodies that are associated with different types of small-vessel vasculitis, including Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and Churg-Strauss syndrome (CSS). Anti-proteinase 3 ANCA are present in more than 90% of patients with systemic WG, and anti-myeloperoxidase (MPO) ANCA in 50-75% of those with MPA and 40-60 % of those with CSS. The pathogenic role of ANCA has been well documented in vivo: passive transfer of anti-MPO ANCA in an MPO knockout mouse model immunized with MPO is sufficient to induce the disease. In vitro, mouse and human anti-proteinase 3 ANCA can activate neutrophils primed with TNF-a and contribute to vasculitic lesions. T-cells are also involved: type 1 helper cytokines have been detected in tissue lesions of limited forms of WG, while type 2 helper cytokines have been identified in its systemic forms. Eosinophils may play a key role in the development of vasculitic lesions in CSS, although this remains to be proved.

[Familial small-vessel vasculitis of the kidney]

INTRODUCTION

Familial forms of small-vessel vasculitis has been reported in 14 families (including this one).

CASES

A father and son were both diagnosed with renal vasculitis (pauci-immune crescentic glomerulonephritis). Both had antimyeloperoxidase autoantibodies, and there was no evidence of a common environmental factor.

DISCUSSION

These cases suggest the role of constitutional factors in the pathogenesis of antineutrophil cytoplasmic antibody-associated vasculitis.

Wegener's granulomatosis: Possible role of environmental agents in its pathogenesis

OBJECTIVE

To investigate the possibility that environmental agents contribute to the pathogenesis of Wegener's granulomatosis (WG).

METHODS

We undertook an extensive search for possible environmental exposures by developing a comprehensive questionnaire that was administered by telephone interview to 53 patients with WG and 2 control groups: one with osteoarthritis and the other with gout. Questions focused on hobbies and vocations, work, home, and allergies. Exact logistic regression was used to calculate odds ratios and 95% confidence intervals after adjusting for potential confounders. After adjusting for age and sex, data are reported for all exposures with odds ratios >2.0 against either control group or for any allergic propensity.

RESULTS

Results suggest that mercury and perhaps lead exposure were positively associated with WG as compared with either control group, although the number of patients exposed was small. A prior history of allergy was also associated with WG as compared with either control group.

CONCLUSION

We conclude that heavy metal exposure and a prior history of allergy may play a role in the etiopathogenesis of Wegener's granulomatosis.

Outcome of ANCA-associated renal vasculitis: a 5-year retrospective study

BACKGROUND

Renal involvement is frequently present in antineutrophil cytoplasmic autoantibody (ANCA)-associated systemic vasculitis and is an important cause of end-stage renal failure (ESRF).

METHODS

This retrospective, multicenter, sequential cohort study reports presenting features and outcome of 246 new patients diagnosed in London, UK, between 1995 and 2000.

RESULTS

Diagnostic subgroups were microscopic polyangiitis, 120 patients (49%); Wegener's granulomatosis (WG), 82 patients (33%); renal-limited vasculitis, 33 patients (13.5%); and Churg-Strauss angiitis, 11 patients (4.5%). Median age was 66 years, 57% were men, and median creatinine level at presentation was 3.87 mg/dL (342 micromol/L). ANCA was present in 92%. Cumulative patient survival at 1 and 5 years was 82% and 76%, respectively. Mortality was associated with age older than 60 years (P < 0.001), development of ESRF (P < 0.001), initial creatinine level greater than 2.26 mg/dL (200 micromol/L; P = 0.01), and sepsis (P < 0.048). ESRF occurred in 68 patients (28%), of whom 47% died. Fifty-six patients who presented with a creatinine level greater than 5.65 mg/dL (500 micromol/L) survived, and 31 patients (55%) achieved dialysis independence. Relapse occurred in 34% after a median of 13 months and was more common in patients with WG (P = 0.048) and proteinase 3-ANCA (P = 0.034). Leukopenia occurred in 41% and was associated with sepsis (P < 0.001).

CONCLUSION

Mortality and morbidity of ANCA-associated systemic vasculitis are improving compared with previous series, but remain high. Renal vasculitis often affects older patients, who have a particularly poor outcome. Early diagnosis improves outcome. Leukopenia, caused by immunosuppressive therapy, should be avoided because of the close association with sepsis and death.

ANCA-associated vasculitis in Greek siblings with chronic exposure to silica

We present the case of two siblings with similar environmental exposure to silica. Both of them developed perinuclear antineutrophil cytoplasmic antibody (p-ANCA)-associated vasculitis with pulmonary-renal syndrome. p-ANCAs were present with antimyeloperoxidase specificity on capture enzyme-linked immunosorbent assay. Treatment with corticosteroids and cyclophosphamide resulted in resolution of the clinical picture. Chronic exposure to silica is the leading environmental factor associated with ANCA-positive vasculitis. Several clusters of systemic vasculitis have been described. Positive and negative human leukocyte antigens (HLA) have been reported in systemic vasculitis. Affected brothers in our case shared one parental HLA haplotype. To the best of our knowledge, this is the first report of a family cluster of silica-induced, ANCA-associated systemic vasculitis with members sharing some of their HLA antigens.

Incidence and outcome of pauci-immune rapidly progressive glomerulonephritis in Wessex, UK: a 10-year retrospective study

BACKGROUND

The Wessex Renal Unit serves a large stable population (2.5 million). Pauci-immune rapidly progressive glomerulonephritis (RPGN) is a frequent cause of acute renal failure requiring admission to our unit ( approximately 8%). At a population level, little is known of the epidemiology and outcome of RPGN.

METHODS

Between 1 April 1986 and 31 March 1996, 141 cases of biopsy proven pauci-immune RPGN were seen in the Wessex region. The records of 128 patients were reviewed. Median (range) follow-up was 1.8 (0.9-9.64) years from diagnosis.

RESULTS

The incidence of 4 per million was stable throughout the period. No clustering was seen. The diagnosis was made (median, 25th, 75th centile) 78.5 (45, 166) days after symptom onset. Co-morbidity (mostly hypertension) was seen in 47% of patients. Other organs affected were lungs 63%, nose/sinuses 50%, joints 42%, muscle 33%, skin 22% and nervous system 14%. Anti-neutrophil cytoplasmic antibody (ANCA) was positive in 73%; cytoplasmic ANCA 34%, peri-nuclear ANCA 26% and undifferentiated 14%. Twenty-seven per cent tested ANCA negative. The differences between the groups were small; time to diagnosis was shorter in the ANCA negative (-ve) group (P=0.02) and there were more airway symptoms in the ANCA positive (+ve) group (P:<0.05). All biopsies demonstrated a necrotizing process; crescents were seen in 96% involving (mean+/-SD) 54+/-26% of the glomeruli. Creatinine concentration (mean+/-SD) at diagnosis was 806+/-540 micromol/l. Treatment followed established immunosuppressive regimens. Initial dialysis was required by 59%, 36% needing long-term dialysis. At 1 year 68% were alive. The need for dialysis (P=0.0004) and age (P=0. 004) were poor prognostic markers. Ten per cent were transplanted, graft survival was 90% at 1 year, no recurrence was seen.

CONCLUSIONS

This study, looking at a large cohort, has established the incidence and outcome of ANCA +ve and ANCA -ve RPGN in a defined stable population. It stresses the similarities between ANCA +ve and ANCA -ve cases and supports the notion that pauci-immune RPGN is part of a continuum of vasculitic illness. In this series transplantation is a safe option.

A familial case of P-ANCA glomerulonephritis presenting in a father and daughter

Antineutrophil cytoplasmic antibodies (ANCA) have proved to be useful serological markers for a subset of vasculitic diseases, including Wegener's granulomatosis, microscopic polyangiitis, and the Churg-Strauss syndrome. The pathogenesis of the ANCA vasculitides remains less clear, including what role, if any, genetic factors play in the expression of ANCA-associated diseases. Familial cases of systemic vasculitis have been reported, and a number of studies have addressed HLA associations of Wegener's and microscopic polyangiitis, but the results have been confusing and inconsistent. We report the first case of P-ANCA-positive vasculitis presenting in a Native American father and daughter. Both patients had systemic vasculitis and were P-ANCA positive with anti-myeloperoxidase (MPO) antibodies.