Sequence-Based Screening of Patients With Idiopathic Polyarteritis Nodosa, Granulomatosis With Polyangiitis, and Microscopic Polyangiitis for Deleterious Genetic Variants in ADA2.

OBJECTIVE: Deficiency of adenosine deaminase 2 (DADA2) is a monogenic form of vasculitis that can resemble polyarteritis nodosa (PAN). This study was undertaken to identify potential disease-causing sequence variants in ADA2 in patients with idiopathic PAN, granulomatosis with polyangiitis (GPA), or microscopic polyangiitis (MPA). METHODS: Patients with idiopathic PAN (n = 118) and patients with GPA or MPA (n = 1,107) were screened for rare nonsynonymous variants in ADA2 using DNA sequencing methods. ADA-2 enzyme activity was assessed in selected serum samples. RESULTS: Nine of 118 patients with PAN (7.6%) were identified as having rare nonsynonymous variants in ADA2. Four patients (3.4%) were biallelic for pathogenic or likely pathogenic variants, and 5 patients (4.2%) were monoallelic carriers for 3 variants of uncertain significance and 2 likely pathogenic variants. Serum samples from 2 patients with PAN with biallelic variants were available and showed markedly reduced ADA-2 enzyme activity. ADA-2 enzyme testing of 86 additional patients revealed 1 individual with strongly reduced ADA-2 activity without detectable pathogenic variants. Patients with PAN and biallelic variants in ADA2 were younger at diagnosis than patients with 1 or no variant in ADA2, with no other clinical differences noted. None of the patients with GPA or MPA carried biallelic variants in ADA2. CONCLUSION: A subset of patients with idiopathic PAN meet genetic criteria for DADA2. Given that tumor necrosis factor inhibition is efficacious in DADA2 but is not conventional therapy for PAN, these findings suggest that ADA-2 testing should strongly be considered in patients with hepatitis B virus-negative idiopathic PAN.

Polyarteritis nodosa and deficiency of adenosine deaminase 2 - Shared genealogy, generations apart.

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that predominantly affects medium-sized arteries. With the establishment and refinement of vasculitis nomenclature and diagnostic criteria, clinical findings of PAN and distinguishing features from other vasculitides are now well characterized. Although PAN typically manifests in adulthood, cohort studies in paediatric patients have shaped our understanding of childhood-onset PAN. The paradigm of childhood-onset PAN changed considerably with the landmark discovery of deficiency of ADA2 (DADA2), a monogenic cause of vasculitis that is often indistinguishable from PAN. Testing for DADA2 has provided an explanation to numerous challenging cases of familial PAN and early-onset PAN around the world. The ability to distinguish DADA2 from classic PAN have important therapeutic implications as tumor necrosis factor inhibitors have demonstrated remarkable efficacy in the treatment of DADA2. In this review, we will discuss our current understanding of PAN and DADA2 and highlight similarities and differences between these vasculitides.

Polyarteritis Nodosa With Reversible FDG Accumulation in Vessels and Kidneys.

A 59-year-old man presented with fever and lower extremity myalgia. Laboratory studies revealed elevated C-reactive protein. F-FDG PET/CT demonstrated FDG uptake not only in the brachial arteries, femoral arteries, and their main ramifications, which were equivalent to small- to medium-sized arteries but also in the kidneys. Angiography revealed a renal aneurysm, confirming the diagnosis of polyarteritis nodosa. The increased FDG uptake in the vessels and kidneys resolved after 6 months of glucocorticoid treatment.

Biomarkers in vasculitis.

PURPOSE OF REVIEW: Biomarkers are considered to be helpful in diagnosing, monitoring, predicting treatment response, and prognosis in clinical practice and as outcomes in clinical trials. In this article, we review the recent literature on new biomarkers and the expanding use of older ones in vasculitic conditions. RECENT FINDINGS: In antineutrophil cytoplasmic antibody-associated vasculitis patients antineutrophil cytoplasmic antibody type may be useful as a predictor of relapse and response to rituximab. Moreover, serial measurements of proteinase-3 titer may help to predict relapse. Urinary soluble CD163 levels are promising for identifying active renal vasculitis. Imaging modalities such as positron emission tomography, computerized angiography tomography, and temporal artery ultrasound maintain their role in diagnosis and disease assessment in large vessel vasculitis. Fecal calprotectin is a useful marker of active gastrointestinal involvement in Behçet's syndrome. SUMMARY: The publications reviewed here potentially may help to move the field of biomarkers in vasculitis management. However, more work toward understanding the underlying pathophysiology and effects of an intervention on the disease process are needed before true biomarkers can be realized. Further studies with appropriate control groups, using good definitions for disease states such as activity and remission are needed to guide our use of these markers correctly in the management of our patients.

Imbalanced expression of dysfunctional regulatory T cells and T-helper cells relates to immunopathogenesis in polyarteritis nodosa.

OBJECTIVES: We investigated the characteristics of circulating T-helper (Th) cells and CD4+ regulatory T cells (Tregs) in polyarteritis nodosa (PAN). METHODS: Peripheral blood samples were obtained from 14 patients with PAN. Nine patients having granulomatosis with polyangiitis (GPA) and 11 healthy individuals (HC) were enrolled as controls. Th cells and Tregs were analyzed by flow cytometry. Suppression assay of Tregs was simultaneously performed by evaluating the proliferation of conventional CD4+ T cells cocultured with Tregs. RESULTS: The frequencies of Th cells were significantly higher in PAN than in HC. In comparison with GPA, the expression of Th1 cells was higher but that of Th17 cells was lower. Additionally, significant increase in Tregs was observed in PAN, which was correlated with the expression of Th1 cells; however, defects in suppressive ability and CTLA-4 expression were observed. The Th1-cell frequency was significantly decreased after immunosuppressive therapy in PAN; however, there were no improvements in other phenotypes or in Treg function. CONCLUSION: T-helper cell expansion and Treg dysfunction are thought to be associated with the pathogenesis of PAN. Th1 cells show a response to immunosuppressive therapy; however, the persistent immune abnormalities may interfere with complete recovery in patients with PAN.

Arterial Remodeling in B-Type Natriuretic Peptide Knock-Out Females.

Sexual dimorphisms are recognized in cardiovascular conditions such as hypertension, stroke, thrombosis and vasculitis. B-type natriuretic peptide (BNP) is a guanylyl cyclase A (GC-A) agonist. The anti-hypertensive, vasodilatory, anti-fibrotic, and anti-hypertrophic properties of BNP are well established in male animal models. Although circulating BNP levels are higher in women, when compared to age-matched men, the cardiovascular protective propensity of BNP in females is poorly understood. We assessed the cardiovascular consequences of BNP deletion in genetically null (Nppb-/-) female rat lines. Throughout the study, blood pressure (BP) remained uninfluenced by genotype, and cardiorenal consequences of BNP knock out remained minor. Unexpectedly, approximately 60% of Nppb-/- females developed mesenteric polyarteritis-nodosa (PAN)-like vasculitis in their life span, some as early as 4 months of age. Mesenteric lesions involved intense arterial remodeling, progressive inflammation, occluded lumens, and less frequently intestinal necrosis and multiple visceral arterial aneurysms. Cumulative pathologies resulted in a significant decline in survival of the Nppb-/- female. This study highlights BNP's vasoprotective propensity, bringing to light a possible sex specific difference in the cardiovascular protection provided by BNP. Defects in the BNP/GC-A/cGMP pathway may play a role in arteriopathies in women, while GC-A agonists may provide effective therapy for arteritis.

AA amyloidosis in a polyarteritis nodosa patient treated with tocilizumab.

Amyloid A (AA) (secondary) amyloidosis represents a severe complication of chronic inflammatory diseases. Since pathogenic mechanisms point to the central role of interleukin 6 (IL-6) in the process of amyloid AA generation, IL-6 blockade seems an attractive therapeutic option. We report a case of a patient with polyarteritis nodosa complicated by AA amyloidosis treated with tocilizumab.

Pathological features of classical polyarteritis nodosa: analysis of 19 autopsy cases.

Classical polyarteritis nodosa (cPN) is a rare autoimmune disease featuring systemic inflammation of middle- and small-sized arteries. Because most of autopsy cases underwent clinical treatment, arterial fibrinoid necrosis, which is the most specific finding of cPN, is often obscure. The aim of this study was to seek morphological characteristics of the middle-sized arteries in autopsy cases of cPN, and to identify immunohistochemical markers for the diagnosis of cPN. Nineteen patients who had undergone autopsy with a diagnosis of cPN were enrolled. Twenty-one autopsy cases without cPN were examined as control group. Arterial fibrinoid necrosis in medium-sized arteries was observed in 8/19 autopsy cases. Elastica van Gieson staining showed an increased number of elastic fiber layers (P<0.0001) and greater distances between elastic fiber layers (P<0.0001) in the renal middle-sized arteries of the cPN group. These findings probably reflected the post-inflammatory remodeling process after necrotizing vasculitis. On immunohistochemical examination, the cPN group showed high matrix metalloproteinase-1 and tumor necrosis factor-α expressions and decreased smoothelin expression in the vascular wall compared to the control group. When uncertain or atypical autopsy cases of cPN are examined, these findings can help to make the pathological diagnosis of cPN.

Role of matrix metalloproteinases, proinflammatory cytokines, and oxidative stress-derived molecules in hepatitis C virus-associated mixed cryoglobulinemia vasculitis neuropathy.

OBJECTIVE: Mixed cryoglobulinemia (MC) is a systemic vasculitis, usually associated with hepatitis C virus (HCV) infection. The molecular mechanisms responsible for HCV-associated MC (HCV-MC) vasculitis are largely unknown. This study was undertaken to assess the expression profile of selected genes involved in inflammatory vascular damage in patients with HCV-MC vasculitis, patients with polyarteritis nodosa (PAN), and patients with noninflammatory idiopathic neuropathy. METHODS: The quantitative expression levels of 42 selected genes involved in inflammatory vascular damage were assessed in nerve lesions of patients with HCV-MC vasculitis, PAN (rheumatic disease controls), and noninflammatory idiopathic neuropathy (noninflammatory neuropathy controls), using real-time reverse transcriptase-polymerase chain reaction. Genes were considered to be differentially expressed when there was a >2-fold difference in mean expression levels between groups and the P value was less than 0.05. RESULTS: Expression levels of 8 genes were significantly increased in HCV-MC patients versus control patients with noninflammatory idiopathic neuropathy, with the highest increase for metallothionein 1 H (MT1H), a hypoxic and oxidative stress protein. Compared with PAN patients, HCV-MC patients had higher expression levels of genes encoding oxidative stress-derived molecules (MT1H, endothelial cell nitric oxide synthase 3, Hsp70, and Hsp90) and tissue plasminogen activator and lower expression levels of matrix metalloproteinase 7 (MMP-7). HCV-MC neuropathies were classified according to their morphologic pattern and the presence or absence of necrotizing arteritis. MMP-1, MMP-7, MMP-9, and interleukin-1beta were up-regulated in patients with necrotizing arteritis. CONCLUSION: This comprehensive molecular study of HCV-MC vasculitis provides strong evidence that MMPs, proinflammatory cytokines, and oxidative stress-derived molecules have a role in the pathogenesis of HCV-MC vasculitis neuropathy.

Isolated necrotizing arteritis (localized polyarteritis nodosa): examination of the histological process and disease entity based on the histological classification of stage and histological differences from polyarteritis nodosa.

INTRODUCTION: Although isolated necrotizing arteritis (INA) has been thought to be an isolated form of polyarteritis nodosa (PAN), a detailed histological comparison between INA and PAN has not been performed. Therefore, we examined the disease entity of INA based on the histological comparison of both diseases. In addition, a histological classification of INA, in which the histological process of INA is included, was described. METHODS: A histological study, including CD3, CD20, and CD68 immunostains, was performed in seven operated patients with INA. Five untreated patients with PAN were also examined. RESULTS: In INA, arteritis with fibrinoid necrosis occurred in small and medium-sized arteries in a single organ. INA was divided histologically into acute (five cases) and healed stage (two cases). Endothelial injury and medial degeneration, followed by fibrinoid necrosis, occurred in the acute stage, and regression of fibrinoid necrosis and fibrosis were present in the healed stage. Infiltration of predominant T lymphocytes and macrophages was also observed in the affected arteries. Histological comparison between INA and PAN led to the finding that the extension of fibrinoid necrosis in the entire arterial wall, which indicates severe wall destruction, intense proliferation of fibroblasts and aneurysm formation occurred in PAN alone. CONCLUSIONS: We demonstrated some histological differences between INA and PAN. Based on the histological similarities and differences between INA and PAN, it was concluded that INA shall be classified as a mildly wall destructive form of PAN-type arteritis located in a single organ.

Tumor necrosis factor blockade in the management of children with orphan diseases.

Tumor necrosis factor (TNF) blockade has been used successfully to treat a number of rheumatic disorders that have a substantial burden of illness. In children, the TNF antagonists are used mainly for the treatment of juvenile idiopathic arthritis (JIA). There are, however, a variety of rare systemic inflammatory diseases, in which TNF blockade appears promising. Preliminary data in adults suggest that several forms of vasculitis appear to be responsive to TNF antagonists-Behcet's disease, polyarteritis nodosa, Wegener granulomatosis, among others. Some of them respond better to infliximab, a chimeric monoclonal anti-TNF antibody, than to etanercept, a recombinant p75 TNF receptor. We describe our limited experience with infliximab in the treatment of three children with rare vasculitic conditions.

Polyarteritis nodosa in association with subarachnoid hemorrhage.

We report a 65-year-old man with classic polyarteritis nodosa (PAN) who developed subarachnoid hemorrhage. Polyarteritis nodosa was strongly suspected, however, the biopsy specimens of kidney and sural nerve showed no findings of vasculitis and the serum titer of antimyeloperoxidase-antineutrophil cytoplasmic autoantibody (MPO-ANCA) was negative. Cranial magnetic resonance angiography showed no findings of aneurysms. He developed subarachnoid hemorrhage (SAH) during the course and died. Autopsy confirmed fibrinoid necrosis in the medium-sized artery of multiple organs. To our knowledge, this is the first report of a case of classic PAN accompanied by SAH in which MPO-ANCA proved negative.

Involvement of chemokines and type 1 cytokines in the pathogenesis of hepatitis C virus-associated mixed cryoglobulinemia vasculitis neuropathy.

OBJECTIVE: To examine the expression profiles of a large number of genes within typical vasculitic nerve lesions in patients with mixed cryoglobulinemia (MC) vasculitis in order to better characterize the molecules involved in cellular tissue activation and trafficking. METHODS: The quantitative expression of 19 genes coding for cytokines, chemokines, and their receptors in the nerve lesions of 9 patients with hepatitis C virus (HCV)-associated MC vasculitis, 7 with idiopathic polyarteritis nodosa (PAN) (rheumatic disease controls), and 8 patients with noninflammatory idiopathic neuropathy (noninflammatory neuropathy controls) was assessed using a real-time reverse transcriptase-polymerase chain reaction procedure. RESULTS: Compared with the noninflammatory controls, HCV-MC vasculitis patients had a significantly higher expression of Th1 cytokines in vasculitic nerve lesions (mean +/- SEM fold increase 33.7 +/- 11.6 for interferon-gamma and 7.2 +/- 1.9 for tumor necrosis factor alpha), whereas Th2 cytokines were absent (interleukin-4 [IL-4], IL-5, and IL-13) or were not significantly different (IL-10). Chemokines involved in T cell and monocyte trafficking were also significantly up-regulated in the HCV-MC vasculitis patients (mean +/- SEM fold increase 27.4 +/- 8.3 for macrophage inflammatory protein 1alpha [MIP-1alpha], 19.9 +/- 5.7 for MIP-1beta, and 7.2 +/- 1.5 for CXCR3). Compared with patients with idiopathic PAN, there was a trend toward higher expression of MIP-1alpha and CXCR3 in HCV-MC vasculitis patients (mean +/- SEM fold increase 27.4 +/- 8.3 versus 5.3 +/- 3.4 for MIP-1alpha and 7.2 +/- 1.5 versus 2.5 +/- 0.9 for CXCR3). CONCLUSION: This study is the first to demonstrate a role of cellular immunity and Th1 lymphocytes in the pathogenesis of HCV-MC vasculitic nerve lesions.

Pain-related differential expression of NGF, GDNF, IL-6, and their receptors in human vasculitic neuropathies.

OBJECTIVE: Pain-related differential expressions of nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF) and interleukin-6 (IL-6), and their receptors were investigated in human vasculitic neuropathies. MATERIALS AND METHODS: The mRNA levels of pain-related neurotrophic factors, NGF, GDNF and IL-6, were examined in the sural nerves of 22 painful and non-painful patients with acute necrotizing vasculitic neuropathies, together with their concomitant soluble receptors (p75, GFR(alpha)-1 and IL-6R(alpha)). RESULTS: The mRNAs for these factors and receptors in the lesioned nerves were up-regulated to a variable extent in both groups. NGF mRNA expression was more closely correlated with that of p75 in painful neuropathy with relatively preserved large fiber density, compared with non-painful neuropathy, though the NGF mRNA level in painful neuropathy was lower than that in non-painful neuropathy. GDNF was closely associated with GFR(alpha)-1 in mRNA levels regardless of the pain state, but IL-6 was not associated with IL-6R(alpha). CONCLUSION: The differential expression of neurotrophic factors and their cognate soluble receptors in human vasculitic neuropathy suggests that NGF, which was effectively transferred to sensory axons with p75, may induce pain.

Expression of glial cell line-derived neurotrophic factor and GDNFR-alpha mRNAs in human peripheral neuropathies.

The steady-state mRNA levels of glial cell line-derived neurotrophic factor (GDNF), GDNFR-alpha and RET were examined in various human peripheral neuropathies to determine the relationship with myelinated fiber pathology, and T cell and macrophage invasions in the diseased nerves. GDNF and GDNFR-alpha mRNA levels were elevated to variable extent in the diseased nerves, although they were not specific to the type of diseases. The increase of GDNFR-alpha mRNA levels was correlated with the extent of the nerves with axonal pathology, and was proportional to the extent of invasion of the nerves by T cells and macrophages. The GDNF mRNA levels were not related to axonal, demyelinating pathology, or inflammatory cell invasions. RET mRNA expression was not detected in normal nor diseased nerves. The GDNF and GDNFR-alpha expression in the diseased human nerves is regulated by an underlying pathology-related process, and could play a role in peripheral nerve repair.

Isolated necrotizing arteritis of the female genital tract: a clinicopathologic and immunohistochemical study of 11 cases.

Isolated necrotizing arteritis (INA) of the polyarteritis-nodosa type localized to the female genital tract is rare. Approximately 30 case reports have been published to date. Eleven additional patients are described here, all with a favorable follow-up. INA is usually localized in the uterine cervix, but, when multifocal lesions are present, the latter is almost always involved. Patients most frequently report menorrhagia or postmenopausal bleeding. With immunohistochemical studies, immune-complex deposits (IgM, IgG, and C'3) in 7 of 11 patients with INA of the female genital tract were demonstrated for the first time. The inflammatory cells were composed mainly of T-lymphocytes with macrophages and scarce B-lymphocytes also present. These results suggest that INA is primarily an immune complex-mediated disease, implicating humoral and cellular mediator systems. Possible pathogenetic factors of INA are immune complex-mediated hypersensitivity reactions to drugs, foreign materials (after cone biopsy or curettage), and cancers, or an autoimmune reaction against constituents of the vessel walls caused by tissue injury after local surgical intervention through in situ immune-complex formation.

Expression of low-affinity neurotrophin receptor p75NTR in the peripheral nervous system of human neuropathies.

Expression of low-affinity neurotrophin receptor (p75NTR) was immunohistochemically examined in the peripheral nerve trunks, dorsal root ganglia, sympathetic nerve ganglia and spinal cords in various human neurological diseases manifesting peripheral neuropathies. p75NTR was expressed in the nerves with axonal degeneration, and was also prominent in the nerves with newly regenerating axons. In contrast, axonal pathology tended to reduce the expression of p75NTR in the neuronal perikarya of the dorsal root ganglion and sympathetic nerve ganglion neurons. In the ventral and lateral horn cells, the p75NTR immunoreactivity was not detected in the normal and diseased nerves except for amyloid polyneuropathy. These p75NTR expressions in the diseased human peripheral nervous tissues would be regulated by an underlying pathology-related process, and could play a role in peripheral nerve repair.

Demonstration of microaneurysms at the interlobular arteries of the kidneys in microscopic polyangiitis: a three-dimensional study.

Aneurysms, mostly saccular, of the medium-sized muscular arteries are frequently encountered in classic polyarteritis nodosa, whereas their occurrence in smaller arteries is unclear. The objective of this study is to clarify the three-dimensional morphology of the small-sized muscular arteries involved in microscopic polyangiitis (MPA). Six autopsy cases of MPA of the acute inflammatory stage were chosen. Using serial paraffin-embedded sections of the kidney, vasculitic lesions observed in the interlobular arteries were three-dimensionally reconstructed. All of the 19 lesions showed microaneurysms, of which 18 were sausage-shaped and the other was saccular. In the former type, average outer diameter at the most expanded point was 235.4 +/- 83.8 microm (mean +/- SD), which was 2.78 +/- 0.73 times that of an uninvolved adjacent arterial diameter. The major axis-minor axis ratio in a cross-aneurysmal section was 1.17 +/- 0.16, indicating rather regular centrifugal expansion of the aneurysm. The aneurysmal length was 742.7 +/- 254.8 microm. These sausage-type aneurysms showed whole circumferential vasculitic involvement, whereas the saccular-type aneurysm contained an uninvolved arterial portion. In both types, the luminal spaces showed similar three-dimensional features to the outer surface of microaneurysms It was concluded that the interlobular arteries of the kidneys in MPA were characterized by formation of microaneurysms, most of which were sausage-shaped

Dynamic pattern of endothelial cell adhesion molecule expression in muscle and perineural vessels from patients with classic polyarteritis nodosa.

OBJECTIVE: To investigate endothelial cell adhesion molecule expression in vessels from patients with classic polyarteritis nodosa (PAN). METHODS: Frozen sections of 21 muscle and 16 nerve samples from 30 patients with biopsy-proven PAN and 12 histologically normal muscle and 2 histologically normal nerve samples from 12 controls were studied immunohistochemically, using specific monoclonal antibodies (MAb) that recognize adhesion molecules. Adhesion molecules identified were intercellular adhesion molecule 1 (ICAM-1), ICAM-2, ICAM-3, vascular cell adhesion molecule 1 (VCAM-1), platelet endothelial cell adhesion molecule 1 (PECAM-1), E-selectin, P-selectin, L-selectin, lymphocyte function-associated antigen 1 (LFA-1), and very late activation antigen 4 (VLA-4). Neutrophils were identified with a MAb recognizing neutrophil elastase. Endothelial cells were identified with the lectin ulex europaeus. RESULTS: In early lesions, expression of PECAM-1, ICAM-1, ICAM-2, and P-selectin was similar to that in control samples, and VCAM-1 and E-selectin were induced in vascular endothelium. In advanced lesions, immunostaining for adhesion molecules diminished or disappeared in luminal endothelium, whereas these molecules were clearly expressed in microvessels within and surrounding inflamed vessels. Staining in endothelia from vessels in a healing stage tended to be negative. A high proportion of infiltrating leukocytes expressed LFA-1 and VLA-4, and only a minority expressed L-selectin. No relationship between the expression pattern of adhesion molecules and clinical features, disease duration, or previous corticosteroid treatment was observed. CONCLUSION: Endothelial adhesion molecule expression in PAN is a dynamic process that varies according to the histopathologic stage of the vascular lesions. The preferential expression of constitutive and inducible adhesion molecules in microvessels suggests that angiogenesis contributes to the persistence of inflammatory infiltration in PAN.