Nomenclature of vasculitic syndromes: a historical perspective

Are classification criteria for vasculitis useful in clinical practice? Observations and lessons from Colombia

INTRODUCTION

Idiopathic systemic vasculitis represents a group of clinical entities having non-specific etiology with the common characteristic of acute or chronic inflammatory compromise of the small and large vessels walls, associated with fibrinoid necrosis.

OBJECTIVES

To describe the most common inflammatory vascular diseases in a long historical cohort of patients from San Juan de Dios Hospital located in Bogota, Colombia using two different systems and a clinical histopathological correlation format, and to make a comparison between them.

METHODS

We reviewed all previously ascertained cases of vasculitis confirmed by biopsy processed between 1953 and 1990, and systematically collected data on all new cases of vasculitis from 1991 to 1997 at the Hospital San Juan de Dios (Bogota-Colombia). The cases were classified in accordance with the Chapel Hill Consensus criteria, and the system proposed by J.T. Lie.

RESULTS

Of 165,556 biopsy tissue specimens obtained during this period from our hospital, 0.18% had vasculitis, perivasculitis or vasculopathy. These included 304 histopathological biopsies from 292 patients. Cutaneous leukocytoclastic vasculitis (64 histological specimens) was the most frequently encountered type of "primary" vasculitis followed by thromboangiitis obliterans (38 specimens), and polyarteritis nodosa (24 specimens). Vasculitis associated with connective tissue diseases (33 specimens) and infection (20 specimens) were the main forms of secondary vasculitis, a category that was omitted from the Chapel Hill consensus report. We found that 65.8% of our histopathological diagnoses could not be classified according to the Chapel Hill classification, and 35.2% could not be classified according to the classification of Lie. Only 8.9% of cases remained unclassified by our system after clinical and histological correlation.

CONCLUSION

Current vasculitis classification schemes are designed for classification, rather that diagnosis of disease and do not adequately address some common forms of inflammatory vascular diseases, including those of infectious etiology and unusual etiology seen in clinical practice. Based on our clinical experience, we suggest a classification outline which practitioners can use which emphasizes correlation of the clinical picture to the histopathology findings for diagnosis and therapy, which may promote better clinical practice and standardization for clinical trials.

Classification and diagnostic criteria in systemic vasculitis

Approximately 20 different primary forms of vasculitis are recognized, not all of which have been included in classification schemes or consensus statements regarding nomenclature. A variety of classification schemes have been proposed over the past 50 years, many predicated upon the size of the primary type of vessel involved in a given disease, as well as other considerations that include demographic features, organ tropism, the presence or absence of granulomatous inflammation, the role of immune complexes in pathophysiology and the association of autoantibodies with some forms of vasculitis. All classification schemes to date have had shortcomings owing to the substantial gaps in knowledge about vasculitis, but the American College of Rheumatology criteria for the classification of some forms of vasculitis are useful for the purpose of including patients in research studies. The Chapel Hill Consensus Conference has clarified some existing controversies in nomenclature of the systemic vasculitides. Robust diagnostic criteria for the various forms of vasculitis have, however, remained elusive.

Historical perspective of vasculitis: polyarteritis nodosa and microscopic polyangiitis

The original and early case reports of vasculitis provide a historical context and foundation for understanding current concepts of these diseases. These early case reports are valuable as reference points for the current efforts in diagnosing, treating, and classifying vasculitis. In addition, they emphasize the importance of careful clinical observation in these efforts and the essential nature of medical science. Polyarteritis nodosa was the first noninfectious vasculitis to be described and studied in detail. Research on this group of vasculitides has been the cornerstone for understanding the pathophysiology of other forms of idiopathic vasculitis. Historically, most forms of vasculitis described subsequently have been characterized and classified on the basis of features similar to or distinct from polyarteritis.

Irregular cytokine pattern of CD4+ T lymphocytes in response to Staphylococcus aureus in patients with Wegener's granulomatosis

The initial stage of Wegener's Granulomatosis (WG) is often marked by symptoms of infection and it has been postulated that a bacterial infection could be the aetiologic factor of this disease. The objective of our work was to investigate T-cell-mediated immunity in WG by testing proliferative responses on bacterial antigens and particularly Staphylococcus aureus. We investigated the bulk proliferative response of peripheral blood lymphocytes (PBL) from patients with clinically active WG to gram-positive bacteria and purified proteinase 3 (PR-3), the major target antigen of c-ANCA. We generated S. aureus-specific PBL-derived T-cell lines and T-cell clones (TLC). In two WG patients 27 TLC were characterized in terms of reactivity to bacterial antigens/PR-3, phenotype, HLA class II restriction and pattern of cytokine secretion. Compared to coagulase-negative Staphylococci and beta-haemolytic Streptococci A, reactivity to S. aureus was significantly increased in all patients with WG. Using purified PR-3, we found a PBL proliferation in five out of 25 WG patients. The TLC were S. aureus-specific and did not cross-recognize Streptococci or coagulase-negative Staphylococci. The S. aureus-specific TLC were of the alphabeta-TCR+ CD4+ phenotype and HLA-DR-restricted. These TLC predominantly showed a Th2-type of cytokine secretion. Interestingly, seven of the S. aureus-reactive TLC also recognized the PR-3 antigen. From these data we conclude that Staphylococci-specific HLA-DR-restricted CD4+ T cells may play a key role in the initial triggering of immune responses in WG.

Colonic ulcers in a patient with hepatitis C virus-associated polyarteritis nodosa

An elderly woman presented with abdominal discomfort, pulmonary infiltrates, acute renal failure, purpura, and massive hematochezia. Numerous colonic ulcers with underlying fibrinoid necrotizing arteritis were found in the colectomy specimen. Anti-hepatitis C virus (HCV) antibodies and HCV RNA were present in the serum. The diagnosis of HCV-associated polyarteritis nodosa was clear. This clinical presentation differs from the more commonly occurring vasculitis complicating HCV infection, which is of the leukocytoclastic type, and is associated with overt liver disease and cryoglobulinemia. In our patient, results of liver tests were normal, there was no cryoglobulinemia, and the vasculitis was of the fibrinoid necrotizing arteritis type. HCV-associated polyarteritis nodosa should be considered in the differential diagnosis of necrotizing fibrinoid arteritis even in a patient with normal liver function test results and in the absence of cryoglobulinemia.

Effect of diagnostic delay on disease severity and outcome in glomerulonephritis caused by anti-neutrophil cytoplasmic antibodies

AIMS

To measure the time between onset of symptoms and intention to treat in patients with anti-neutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis; and to investigate the effect of any delay in diagnosis on disease severity at presentation and outcome.

METHODS

All ANCA positive patients with biopsy proven glomerulonephritis presenting in the North West Region over a consecutive period of 57 months were identified from the North West Glomerular Disease Registry. Sixty nine patients were identified and notes from 61 were reviewed.

RESULTS

The 61 patients had a median diagnostic delay of 92 days. In only 12 patients had an ANCA test been performed prior to the nephrology referral. Thirty three patients had renal failure requiring dialysis within one week of admission and had a shorter delay (median 72 days) than those not requiring dialysis (median 132 days). None of the 28 patients with independent renal function at presentation required dialysis subsequently. Eighteen (55%) of those who required dialysis recovered independent renal function at three months and 13 (39%) had long term recovery. Both for patients who did and did not undergo dialysis, a longer delay was correlated with an increased percentage of sclerotic glomeruli at presentation. Patients with end stage renal failure had a median delay of 92 days, compared with one of 42 days in those who were dialysis independent at final follow up.

CONCLUSIONS

Prolonged delay in diagnosis of ANCA associated glomerulonephritis is associated with an increased risk of end stage renal failure.

Prognostic factors in polyarteritis nodosa and Churg-Strauss syndrome. A prospective study in 342 patients

We undertook this study to determine the clinical, biologic, immunologic, and therapeutic factors associated with the prognoses of polyarteritis nodosa (PAN) and Churg-Strauss syndrome (CSS). Three hundred forty-two patients (260 with PAN, 82 with CSS) followed from 1980 to 1993 were included in a prospective study on prognostic factors. Two hundred eighty-eight of these patients were included in the prospective studies on PAN and CSS. Items to be considered for analysis were collected at the time of diagnosis, during the acute phase of the disease. A survival curve was plotted for each clinical and biologic symptom observed in PAN or CSS. Each treatment arm of the prospective therapeutic trials was also tested: 1) prednisone (CS) + oral cyclophosphamide (CYC) + plasma exchanges (PE) versus CS E, 2) CS + PE versus CS, 3) CS + oral CY versus CS + pulse CY, 4) CS + pulse CY + PE versus CS + pulse CY in severe PAN and CSS, and 5) PE + antiviral agents after short-term CS in hepatitis B virus-related PAN. Of the parameters thus evaluated, the following had significant prognostic value and were responsible for higher mortality: proteinuria > 1 g/d (p < 0.0001; relative risk [RR] 3.6), renal insufficiency with serum creatinine > 1.58 mg/DL (p < 0.02; RR 1.86), GI tract involvement (p < 0.008. RR 2.83 for surgery). Cardiomyopathy and CNS involvement were associated with a RR of mortality of 2.18 and 1.76, respectively; these were not statistically significant. Similar survival rates were obtained with the prospectively tested therapies. The five-factors score (FFS) we established considered the prognostic factors creatinemia, proteinuria, cardiomyopathy, GI tract involvement, and CNS signs. Multivariate analysis showed that proteinuria (due to vascular or glomerular disease) and GI tract involvement were independent prognostic factors. When FFS = 0 (none of the 5 prognostic factors present), mortality at 5 years was 11.9%; when FFS = 1 (1 of the 5 factors present), mortality was 25.9% (p < 0.005); when FFS > 2 (3 or more of the 5 factors present), mortality was 45.95% (p < 0.0001 between 0 and 2, p < 0.05 between 1 and 2). We conclude that an initial assessment of PAN or CSS severity enables outcome and mortality to be predicted. The FFS is a good predictor of death and can be used to help the clinician choose the most adequate treatment. Renal and GI signs are the most serious prognostic factors.

Cell-mediated autoimmunity in patients with Wegener's granulomatosis (WG)

Despite the well described infiltration of cells of the cellular immune system in vasculitic lesions and the granuloma formation in patients with WG, the role of T cell-mediated autoimmunity in WG is not clear. Reports of T cell proliferation in response to neutrophil azurophilic granule proteins are contradictory. In this study we have assessed the proliferation of T cells of WG patients to purified proteinase 3 (PR3) and to total azurophilic granule proteins in two different assays. In addition to the classical proliferation assay with isolated peripheral blood mononuclear cells, we have used a whole blood proliferation assay. In both assays we found proliferative responses to PR3 in patients with WG. The number of patients reacting to the azurophilic granule extract was higher than the patients reacting to the purified PR3, suggesting that other autoantigens may also be involved. We have identified epitopes of PR3 that may be potential targets of class I-restricted T cell responses in the context of HLA-A*0201, the most common MHC class I molecule. These epitopes were determined by the binding of synthetic PR3 peptides to HLA-A*0201 on the antigen-processing defective cell line, T2. In addition, T cell lines were established from tissue biopsies, obtained from WG patients, and assessed for cytolytic reactivity against T2 cells, preloaded with synthetic PR3 peptides. We conclude that T lymphocytes of WG patients have increased proliferative responses to purified PR3 and to a larger extent to non-fractionated proteins of azurophilic granules of polymorphonuclear neutrophilic leucocytes (PMN).

A novel class of autoantigens of anti-neutrophil cytoplasmic antibodies in necrotizing and crescentic glomerulonephritis: the lysosomal membrane glycoprotein h-lamp-2 in neutrophil granulocytes and a related membrane protein in glomerular endothelial cells

Necrotizing and crescentic glomerulonephritis (NCGN) is frequently associated with circulating antineutrophil cytoplasmic autoantibodies (ANCA). It is established that ANCA are specific for soluble enzymes of granules of polymorphonuclear neutrophil granulocytes (PMN), such as myeloperoxidase (MPO) or protease 3 (PR3). The purpose of this study was to identify membrane proteins of PMNs, and/or glomerular cells, as additional autoantigenic ANCA targets. When membrane protein fractions were prepared from PMNs and isolated human glomeruli, and immunoblotted with ANCA sera of NCGN patients, two bands with apparent molecular masses of 170 and 80-110 kD (gp170/80-110) were labeled in PMNs, and a 130-kD glycoprotein (gp130) in glomeruli. Gp130 was purified, and monoclonal and rabbit antibodies (Abs) were produced which showed the same double specificity as the patient's ANCA. Using these probes, evidence was provided that gp170/80-110 is identical with human lysosomal-associated membrane protein 2 (h-lamp-2), because both proteins were immunologically cross-reactive and screening of a cDNA expression library from human promyelocytic leukemia cells with anti-gp130 Ab yielded a clone derived from h-lamp-2. Gp170/80-110 was localized primarily in granule membranes of resting PMNs, and was translocated to the cell surfaces by activation with FMLP. By contrast, gp130 was localized in the surface membranes of endothelial cells of human glomerular and renal interstitial capillaries, rather than in lysosomes, as found for h-lamp-2. Potential clinical relevance of autoantibodies to gp170/80-110 and gp130 was assessed in a preliminary trial, in which ANCA sera of patients (n = 16) with NCGN were probed with purified or recombinant antigens. Specific reactivity was detected in approximately 90% of cases with active phases of NCGN, and frequently also in combination with autoantibodies specific for PR3 or MPO. Collectively, these data provide evidence that h-lamp-2 in PMNs and a different, structurally related 130-kD membrane protein on the cell surface of renal microvascular endothelial cells are autoantigenic targets for ANCA in patients with active NCGN.

Vasculitis in childhood

Systemic vasculitic syndromes are rare in childhood. Vasculitis is the predominant feature of a large number of different clinical entities that are linked by the presence of inflammatory changes in the blood vessels. The nature of these diseases and their relationship to each other remain unclear. The clinical presentation associated with the size of the affected vessels and epidemiological data are very helpful for the diagnosis of those diseases. Recent advances are beginning to shed some light on the etiology and pathogenetic mechanisms involved in the various vasculitides. There is good evidence to support roles for circulating immune complexes, cell-mediated immunity, anti-neutrophil cytoplasmic antibodies and anti-endothelial cell antibodies in the pathogenesis. Renal involvement in vasculitis in children is commonly seen in Henoch-Schönlein purpura, microscopic polyarteritis, Wegener's granulomatosis, Churg-Strauss syndrome and polyarteritis nodosa. However, kidney disease can also be part of the clinical picture of Kawasaki disease and Takayasu arteritis. Recently, with the institution of early and aggressive immunosuppressive treatment of severe cases, significant improvement in the long-term survival of patients has been achieved. This review article addresses the pathological and clinical features (particularly renal involvement), therapeutic intervention and prognosis of the above-mentioned diseases.

Anti-neutrophil cytoplasmic auto-antibodies-associated vasculitis with pulmonary and renal involvement

We present a 13-year-old boy with a rapidly progressive glomerulonephritis and pulmonary haemorrhage with perinuclear anti-neutrophil cytoplasmic auto-antibodies (pANCA) corresponding to anti-myeloperoxidase antibodies. The diagnosis of microscopic polyarteritis was made on the basis of the clinical features, the positivity of pANCA, and the histological finding of a pauci-immune crescentic glomerulonephritis. He responded excellently to corticosteroids and cyclophosphamide therapy and complete clinical remission persists 1 year after withdrawal of treatment. We emphasize the usefulness of ANCA antibody assays to establish a prompt diagnosis and adequate treatment in systemic vasculitis in children.