Reduced CD5(+) CD24(hi) CD38(hi) and interleukin-10(+) regulatory B cells in active anti-neutrophil cytoplasmic autoantibody-associated vasculitis permit increased circulating autoantibodies

Pathogenesis of anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis is B cell-dependent, although how particular B cell subsets modulate immunopathogenesis remains unknown. Although their phenotype remains controversial, regulatory B cells (Bregs ), play a role in immunological tolerance via interleukin (IL)-10. Putative CD19(+) CD24(hi) CD38(hi) and CD19(+) CD24(hi) CD27(+) Bregs were evaluated in addition to their CD5(+) subsets in 69 patients with ANCA-associated vasculitis (AAV). B cell IL-10 was verified by flow cytometry following culture with CD40 ligand and cytosine-phosphate-guanosine (CpG) DNA. Patients with active disease had decreased levels of CD5(+) CD24(hi) CD38(hi) B cells and IL-10(+) B cells compared to patients in remission and healthy controls (HCs). As IL-10(+) and CD5(+) CD24(hi) CD38(hi) B cells normalized in remission within an individual, ANCA titres decreased. The CD5(+) subset of CD24(hi) CD38(hi) B cells decreases in active disease and rebounds during remission similarly to IL-10-producing B cells. Moreover, CD5(+) B cells are enriched in the ability to produce IL-10 compared to CD5(neg) B cells. Together these results suggest that CD5 may identify functional IL-10-producing Bregs . The malfunction of Bregs during active disease due to reduced IL-10 expression may thus permit ANCA production.

Pathways to renal biopsy and diagnosis among patients with ANCA small-vessel vasculitis

OBJECTIVES

Antineutrophil cytoplasmic antibody small-vessel vasculitis (ANCA-SVV) is an autoimmune systemic process increasingly recogniSed since the advent of antibody testing for the disease. Prompt diagnosis and institution of immunosuppressive therapy has been shown to improve patient outcome. The goal of this study was to better understand how patients navigate the health care system from symptom presentation to biopsy diagnosis, and to study the effects of prompt versus delayed diagnosis.

METHODS

Disease symptoms and number of physicians seen prior to renal biopsy were assessed for 127 ANCA-SVV patients. Direct, delayed, and quest pathways to diagnosis and treatment of vasculitis were defined for both patients and providers. Kruskal-Wallis and Fisher exact tests were used to evaluate continual measures and compare categorical variables across pathways.

RESULTS

Among patients who sought direct care, physician delay in referral to a nephrologist was common (49/127, 71%, p=0.0023). Patients who delayed seeking care also experienced a delayed diagnosis 57% of the time (p=0.0023). Patients presenting with prodromal flu or upper respiratory involvement were more likely to have a delay/quest patient pathway (56% and 55%, respectively) than a direct patient pathway (44%, p=0.033 and 45%, p=0.019, respectively). There was a trend for patients with more severe loss of renal function to have a more direct referral to a nephrologist.

CONCLUSIONS

Delay in diagnosis of ANCA SVV may be due to lack of or non-specific symptoms, especially in patients who present with non-renal manifestations of disease. Better algorithms are needed to identify extra-renal manifestations, expedite diagnosis and improve patient outcomes.

Epigenetics and complementary proteins

Although studies on the immunopathogenesis of anti-neutrophil cytoplasm antibody (ANCA) vasculitis have been directed at understanding the autoantibody, there is growing evidence that points to the importance of ANCA autoantigen genes and their regulation. Transcriptional analysis indicates that ANCA autoantigen genes are active in mature neutrophils of ANCA vasculitis patients compared to healthy controls. The unusual transcriptional state of neutrophils from ANCA vasculitis patients appears to be a consequence of failed or disrupted epigenetic silencing. Defective epigenetic silencing could have global effects, by altering the transcriptional and phenotypic state of neutrophils, or local effects by permitting transcription of autoantigen genes from both strands resulting in anti-sense transcripts. Although the role of anti-sense transcripts is currently unknown, there are two intriguing possibilities. Anti-sense transcripts could function (as described for other genes) in transcriptional silencing of autoantigen genes, which takes place in normal neutrophil progenitors. In the setting of failed epigenetic silencing, the fate of anti-sense transcripts may be pathological and serve as a template for production of complementary autoantigens. The observation that ANCA vasculitis patients have anti-sense transcripts and antibodies to complementary proteins is consistent with a role of anti-sense transcripts in complementary protein production. A better understanding of epigenetic silencing and complementary proteins in ANCA vasculitis may unlock the underlying pathology of this condition.

Leukocyte gene expression signatures in antineutrophil cytoplasmic autoantibody and lupus glomerulonephritis

Leukocytes play a major role in the development and progression of autoimmune diseases. We measured gene expression differences in leukocytes from patients that were antineutrophil cytoplasmic autoantibody (ANCA) positive, patients with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA), and healthy donors to explore potential pathways for clinical intervention. Leukocyte gene expression profiles were determined on Affymetrix U133A/B chips in 88 autoimmune patients, 28 healthy donors, and healthy donor leukocyte cell subtypes that were activated in vitro. Comparison of gene expression in leukocytes identified differentially expressed signature genes that distinguish each donor source. The microarray expression levels for many signature genes correlated with the clinical activity of small vessel vasculitis in the ANCA patients; a result confirmed by quantitative real time-polymerase chain reaction for 16 relevant genes. Comparison with in vitro-activated leukocyte subtypes from healthy donors revealed that the ANCA signature genes were expressed by neutrophils while the SLE signature genes were expressed in activated monocytes and T cells. We have found that leukocyte gene expression data can differentiate patients with RA, SLE, and ANCA-related small vessel vasculitis. Monitoring changes in the expression of specific genes may be a tool to help quantify disease activity during treatment.

The role of pathology in the diagnosis of systemic vasculitis

Pathologic processes are underlying defining features of systemic vasculitis. When these pathologic processes can not be observed directly, surrogate signs and symptoms of disease must be used to conclude that vasculitis is present in a patient and, if so, to determine what specific type of vasculitis is present. This review briefly describes the most defining pathologic features of giant cell arteritis, Takayasu arteritis, polyarteritis nodosa, Henoch-Schönlein purpura, cryoglobulinemic vasculitis, Kawasaki disease, microscopic polyangiitis, Wegener's granulomatosis and Churg-Strauss syndrome; and discusses how these pathologic features can be integrated with clinical and laboratory data to reach an actionable diagnosis.

Interleukin-18, neutrophils, and ANCA

Hewins et al. show that IL-18 is expressed in the kidneys of patients with ANCA-associated glomerulonephritis, and that IL-18 primes neutrophils via p38 MAPK. These findings suggest a role for IL-18, including IL-18-induced T(H)1 polarization and IFN-gamma production, in the progression of ANCA disease.

Clinical and pathologic characteristics of focal segmental glomerulosclerosis pathologic variants

Histologic variants of idiopathic focal segmental glomerulosclerosis (FSGS) may have prognostic value. A recent working classification system has distinguished five FSGS variants. We evaluated a cohort of adult patients with biopsy-proven FSGS diagnosed between March 1982 and July 2001 to determine if subtypes were associated with renal outcome. Renal biopsies were reviewed by two pathologists. Demographic and clinical data were obtained from charts. Outcomes were partial and complete remission of the nephrotic syndrome, and renal failure. The frequency of FSGS variants was: 3% cellular (N=6), 11% collapsing (N=22), 17% tip lesion (N=34), 26% perihilar (N=52), and 42% not otherwise specified (NOS) (N=83). Collapsing FSGS affected younger and more often black patients. Black race was uncommon in tip variant. Collapsing and tip variants had higher proteinuria and lower serum albumin than perihilar and NOS variants. Better renal function and less severe tubulointerstitial injury were observed in patients with tip variant. These patients were more likely to receive steroids and more often achieved complete remission (50%). After a median follow-up of 1.8 years, 23% of patients were on dialysis and 28% had renal failure. Collapsing FSGS had worse 1-year (74%) and 3-year (33%) renal survival compared to other variants (overall cohort renal survival at 1 and 3 years: 86 and 67%). Different histologic variants of FSGS have substantial differences in clinical features at the time of biopsy diagnosis and substantial differences in renal outcomes.

Mapping of myeloperoxidase epitopes recognized by MPO-ANCA using human-mouse MPO chimers

Myeloperoxidase (MPO) is one of the major target antigens of antineutrophil cytoplasmic autoantibodies (ANCA) found in patients with small-vessel vasculitis and pauci-immune necrotizing glomerulonephritis. To date, the target epitopes of MPO-ANCA remain poorly defined. Human MPO-ANCA do not typically bind mouse MPO. We utilized the differences between human and mouse MPO to identify the target regions of MPO-ANCA. We generated five chimeric MPO molecules in which we replaced different segments of the human or mouse molecules with their homologous counterpart from the other species. Of serum samples from 28 patients screened for this study, 43 samples from 14 patients with MPO-ANCA-associated vasculitis were tested against recombinant human and mouse MPO and the panel of chimeric molecules. Sera from 64 and 71% of patients bound to the carboxy-terminus of the heavy chain, in the regions of amino acids 517-667 or 668-745, respectively. No patient serum bound the MPO light chain or the amino-terminus of the heavy chain. All sera bound to only one or two regions of MPO. Although the pattern of MPO-ANCA binding changed over time (4-27 months) in 6 of 10 patients with several serum samples, such changes were infrequent. Other target regions of MPO-ANCA may not have been detected due to conformational differences between the native and recombinant forms of MPO. MPO-ANCA do not target a single epitope, but rather a small number of regions of MPO, primarily in the carboxy-terminus of the heavy chain.

Difference in antigenic determinant profiles between human and rat myeloperoxidase

We tested whether rat and human MPO have similar antigenic determinants using 36 human MPO-ANCA positive sera, one mouse anti-rat MPO and four mouse anti-human MPO monoclonal reagents. Purified rat and human MPO were used in ELISA, with or without crossinhibition by preincubation with human MPO or irrelevant antigen in the liquid phase. Only one human MPO ANCA positive serum exhibited significant binding in rat MPO ELISA. This binding was poorly inhibited by preincubation with human MPO in the liquid phase, but was conserved after adsorption of non specific anti-rat activity in a chromatography column. Three mouse anti-human MPO IgG monoclonal antibodies did not recognize rat MPO. Only one mouse anti-human MPO IgA monoclonal antibody bound to rat MPO. This binding was poorly inhibited by preincubation with human MPO (35% at 2 micro g/ml). Conversely, the mouse anti-rat MPO monoclonal did not bind human MPO. We have concluded that: (1) Most human MPO-ANCA recognize antigenic determinants on human MPO which are absent on rat MPO. Therefore, human auto-antibodies bind to epitopes which recently appeared after species evolution; (2) Inversely, the mouse anti-rat MPO monoclonal do not bind human MPO. Therefore, rat MPO epitopes have been altered during species evolution; (3) Mice injected with human MPO preferentially develop antibodies against xeno-epitopes which are not present in rodents. Therefore, human MPO may not be the best antigen to raise ANCA in animal models and (4) A comparison of the amino acid sequences of rat and human MPO may help elucidate the major antigenic epitopes.

Microscopic polyangiitis (microscopic polyarteritis)

Microscopic polyangiitis ("microscopic polyarteritis") is a form of necrotizing small vessel vasculitis that most often affects venules, capillaries, arterioles, and small arteries, although it occasionally involves medium-sized arteries. Microscopic polyangiitis is a more appropriate name than microscopic polyarteritis because some patients have no evidence for arterial involvement. The absence or paucity of immunoglobulin localization in vessel walls distinguishes microscopic polyangiitis from immune complex mediated small vessel vasculitis, such as Henoch-Schonlein purpura and cryoglobulinemic vasculitis. Clinical, epidemiological, and pathologic differences warrant the separation of microscopic polyangiitis from polyarteritis nodosa on the basis of involvement of capillaries and venules by the former but not the latter. Pauci-immune necrotizing and crescentic glomerulonephritis, and hemorrhagic pulmonary capillaritis are common in patients with microscopic polyangiitis. Microscopic polyangiitis is the most common cause for pulmonary-renal vasculitic syndrome. The vasculitis in patients with microscopic polyangiitis is pathologically indistinguishable from the vasculitis of Wegener's granulomatosis and Churg-Strauss syndrome. Granulomatous inflammation distinguishes Wegener's granulomatosis from microscopic polyangiitis. Asthma and eosinophilia distinguish Churg-Strauss syndrome from microscopic polyangiitis. Microscopic polyangiitis, Wegener's granulomatosis, and Churg-Strauss syndrome are all associated with circulating antineutrophil cytoplasmic autoantibodies.

Internalization of proteinase 3 is concomitant with endothelial cell apoptosis and internalization of myeloperoxidase with generation of intracellular oxidants

The important issue addressed by the studies presented here is the mechanism of neutrophil-mediated damage to endothelial and epithelial cells during inflammation. Binding of neutrophil-released granule proteins to endothelial cells may be involved in vascular damage in patients with inflammatory vascular diseases. We have determined whether granule proteins proteinase 3(PR3) and/or myeloperoxidase (MPO) are internalized into endothelial cells, as examined by UV light, confocal, and electron microscopy. Coincident induction of apoptosis and/or the generation of intracellular oxidants were monitored. The results indicate that human endothelial cells (human umbilical vein endothelial cells, human umbilical arterial endothelial cells, human lung microvascular endothelial cells) internalize both PR3 and MPO, which are detected on the cell surface, in the cytoplasm, and possibly nuclear. Epithelial cells (small airway epithelial cells) internalized MPO but not PR3, implying that the mechanism of PR3 internalization may be cell-type specific and different from that of MPO. Internalization of PR3, but not MPO, correlated with activation of apoptosis. Internalization of MPO correlated with an increase in intracellular oxidant radicals. The requirement for the proteolytic activity of PR3 for the induction of apoptosis was examined by generating PR3-truncated fragments that did not contain the components of the catalytic triad. An apoptotic function was localized to the C-terminal portion of PR3. These studies reveal novel mechanisms by which the neutrophil granule proteins PR3 and MPO contribute to tissue injury at sites of inflammation.

Theodore E. Woodward Award. Do ANCA cause small vessel vasculitis?

ANCA may be a pathogenetic force, but to date, support for this contention remains indirect. Active immunization with antigen or passive transfer of ANCA has not reproduced small vessel vasculitis (SVV). It is more than likely that if ANCA are pathogenetic, they are involved as one of many simultaneously occurring mechanisms acting in concert with other synergistic inflammatory mediators of disease. These include not only environmental factors such as infection or environmental toxins such as silica, but also genetic factors that are only now being described. The paradigm for this autoimmune process must include several events that occur simultaneously or sequentially, including ANCA, leukocyte activation and injured endothelium.

Restriction in V kappa gene use and antigen selection in anti-myeloperoxidase response in mice

Anti-neutrophil cytoplasmic Abs, directed primarily toward myeloperoxidase (MPO) and proteinase 3, are detected in the majority of patients with distinct forms of small vessel vasculitides and pauci-immune necrotizing glomerulonephritis. However, the origin of these autoantibodies remains unknown. We studied the V region gene use in murine anti-MPO Abs derived from Spontaneous Crescentic Glomerulonephritis/Kinjoh mice. A total of 13 anti-MPO-producing hybridomas were generated from four unimmunized mice. Ten of the 13 hybridomas (corresponding to 3 of 4 clones) expressed Vkappa1C but differed in their use of VH genes. The remaining three hybridomas expressed a Vkappa5 gene. Anti-MPO hybridomas from individual mice were derived from single clones as deduced by sequence similarity and splice-site identity. We found a statistically significant bias of amino acid replacement mutations to the complementarity-determining regions (CDR) in the Vkappa1C-expressing hybridomas. Intriguingly, all 10 Vkappa1C hybridomas share a lysine to glutamate mutation in the CDR1. To determine the effects of somatic V gene mutations on binding to MPO, we generated an anti-MPO Ab with an unmutated Vkappa1C L chain and compared its ability to bind MPO with its mutated counterpart. The mutated hybridoma-derived Ab has a 4.75-fold higher avidity for MPO than the unmutated Ab. These results suggest that: 1) the L chain plays a dominant role in determining Ab specificity to MPO, 2) the anti-MPO Ab response is oligoclonal, consistent with Ag selection, and 3) MPO is a driving Ag in the murine anti-MPO Ab response.

Do vasculitis categorization systems really matter?

The diagnosis of systemic vasculitides is challenging for many reasons. The etiology and pathogenesis of most vasculitides are unknown or incompletely known. Vasculitides have protean and overlapping clinical and pathologic features. There are conflicting if not contradictory approaches to diagnostic categorization. In spite of these challenges, precise diagnostic categorization is essential for appropriate treatment. This overview reviews the history behind the modern approach to diagnosis of selected vasculitides, including giant cell arteritis, Takayasu arteritis, polyarteritis nodosa, Kawasaki disease, Henoch-Schönlein purpura, cryoglobulinemic vasculitis, Wegener's granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome. Evidence is provided that the categorization for systemic vasculitis really does matter.

False-positive myeloperoxidase binding activity due to DNA/anti-DNA antibody complexes: a source for analytical error in serologic evaluation of anti-neutrophil cytoplasmic autoantibodies

Anti-myeloperoxidase antibodies (anti-MPO) are a major type of anti-neutrophil cytoplasmic antibody (ANCA). While evaluating anti-MPO monoclonal antibodies from SCG/Kj mice, we observed several hybridomas that appeared to react with both MPO and DNA. Sera from some patients with systemic lupus erythematosus (SLE) also react with MPO and DNA. We hypothesized that the MPO binding activity is a false-positive result due to the binding of DNA, contained within the antigen binding site of anti-DNA antibodies, to the cationic MPO. Antibodies from tissue culture supernatants from 'dual reactive' hybridomas were purified under high-salt conditions (3 M NaCl) to remove any antigen bound to antibody. The MPO and DNA binding activity were measured by ELISA. The MPO binding activity was completely abrogated while the DNA binding activity remained. The MPO binding activity was restored, in a dose-dependent manner, by the addition of increasing amount of calf-thymus DNA (CT-DNA) to the purified antibody. Sera from six patients with SLE that reacted with both MPO and DNA were treated with DNase and showed a decrease in MPO binding activity compared with untreated samples. MPO binding activity was observed when CT-DNA was added to sera from SLE patients that initially reacted with DNA but not with MPO. These results suggest that the DNA contained within the antigen binding site of anti-DNA antibodies could bind to the highly cationic MPO used as substrate antigen in immunoassays, resulting in a false-positive test.

The life readiness program: a physical rehabilitation program for patients on hemodialysis

Patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD) are typically sedentary and functionally limited as a consequence of their condition. The purpose of this study is to test the effect of a lifestyle physical rehabilitation program (The Life Readiness Program) on physical function in patients with ESRD undergoing HD. Physical function was measured by the Kidney Disease Quality of Life Short Form (KDQOL-SF) physical function score (range, 0 to 100). Eighty-two patients were randomly assigned to a 6-month rehabilitation program (intervention; n = 39) or to standard clinical management alone (control; n = 43). The groups were frequency matched by age, sex, ethnicity, and diabetes as the cause of ESRD. General linear modeling of the change in physical function score was used for multivariate analysis. Physical function scores were not different between groups at baseline. Change in physical function score increased significantly in the intervention group compared with the control group when data were adjusted for the matching variables and adequacy of dialysis (3.2, -3.6; P = 0.04). Additionally, the control group reported more problems with work or daily functions because of emotional problems (P: </= 0.05). In this brief 6-month intervention, The Life Readiness Program showed the therapeutic benefit of a lifestyle rehabilitation program on functional outcomes and health-related quality of life for patients with ESRD undergoing hemodialysis.

Target antigens for anti-neutrophil cytoplasmic autoantibodies (ANCA) are on the surface of primed and apoptotic but not unstimulated neutrophils

The reaction of ANCA with ANCA antigens on the surface of neutrophils may play a critical role in the pathogenesis of ANCA vasculitis. Therefore, an understanding of the circumstances that result in surface expression of these antigens is important for an understanding of pathogenic mechanisms. In this study we investigated the surface expression of ANCA antigens on quiescent, primed, and apoptotic neutrophils. ANCA antigens and other granule constituents were not detected on the surface of neutrophils in freshly heparinized blood. ANCA antigens were on the surface of neutrophils primed by in vitro incubation for 4 h and 8 h. These cells did not show evidence of apoptosis. After 24 h incubation, about 30% of the neutrophils were apoptotic, and ANCA antigens and other granule constituents were present on the surface of both apoptotic and non-apoptotic cells. Our data indicate that there are no ANCA antigens on the surface of quiescent neutrophils, but that they are on the surface of primed neutrophils before the cells become apoptotic, and remain on the surface of cells after they become apoptotic. Based on these observations, we hypothesize that ANCA can react in vivo with primed but not quiescent neutrophils. Previously published observations indicate that the interaction of ANCA with primed neutrophils results in neutrophil activation, which may be involved in the pathogenesis of ANCA vasculitis.

Parvovirus B19 DNA in kidney tissue of patients with focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) represents a clinicopathological syndrome with diverse causes. We examined the possibility that some cases of FSGS are associated with parvovirus B19 infection. We studied renal biopsy tissue from 40 patients, including those with idiopathic FSGS, collapsing FSGS, membranous nephropathy, and minimal change disease, as well as normal renal tissue removed at the time of nephrectomy from 4 patients. DNA was extracted from frozen blocks of kidney tissue and amplified using nested polymerase chain reaction. Parvovirus B19 DNA was amplified from 8 of 10 patients with idiopathic FSGS, 9 of 10 patients with collapsing FSGS, 6 of 10 patients with membranous nephropathy, 5 of 10 patients with minimal change disease, and 2 of 4 cancer nephrectomy samples. The prevalence of parvovirus B19 DNA was greater among patients with idiopathic FSGS and collapsing FSGS compared with patients with other diagnoses (P = 0.05). In situ hybridization studies using digoxigenin-labeled DNA probes failed to detect parvovirus B19 nucleic acid in any of the kidney tissue samples. These results suggest that parvovirus B19 DNA is commonly found in the kidneys of patients with a range of renal diagnoses, possibly representing latent DNA from past infection. The failure to localize parvovirus B19 nucleic acid within kidney argues against ongoing, high-level viral replication. Nevertheless, the increased prevalence of B19 DNA in patients with idiopathic FSGS and collapsing FSGS could indicate a pathogenic role for the virus in the cause of FSGS in certain patients.

ANCA antigens, proteinase 3 and myeloperoxidase, are not expressed in endothelial cells

BACKGROUND

One hypothesis for the pathogenesis of vasculitis associated with antineutrophil cytoplasmic autoantibodies (ANCAs) proposes that ANCAs bind to ANCA antigens, such as proteinase 3 (PR3) or myeloperoxidase (MPO), which are produced by endothelial cells and expressed on their surfaces. There are conflicting reports, however, on whether endothelial cells express the ANCA antigen PR3, and there are no reports on endothelial expression of MPO. The aim of this study was to determine the presence or absence of PR3 and MPO mRNA in both venous and arterial endothelial cells, employing standard reverse transcription-polymerase chain reaction (RT-PCR) techniques and also the quantitative and highly specific method, TaqMan PCR.

METHODS

RT-PCR (with 3 primer sets) and TaqMan PCR, a method for detecting low copy transcripts, were used to probe for PR3 and MPO transcripts in human endothelial cells from umbilical vein (HUVEC) and artery (HUAEC) and from lung microvascular (HLMVEC). Cells were treated with interferon-gamma (200 units/mL) or tumor necrosis factor-alpha (3 or 10 ng/mL) or both.

RESULTS

Transcripts for PR3 and/or MPO were not detected in HUVEC, HUAEC, and HLMVEC by standard RT-PCR. Analyses for PR3 protein confirmed that PR3 is not expressed in HUVEC. HUVEC and HUAEC were negative for PR3 and MPO by TaqMan PCR.

CONCLUSIONS

PR3 and MPO are not expressed in HUVEC, HUAEC, or HLMVEC. Endothelial cell presentation of endogenous PR3 and MPO antigens is not involved in the pathogenesis of ANCA-associated vasculitis. Alternative explanations need to be explored to determine the pathogenic effect of ANCAs.

ANCA glomerulonephritis and vasculitis: a Chapel Hill perspective

Microscopic polyangiitis, Wegener's granulomatosis, Churg-Strauss syndrome, and pauci-immune necrotizing glomerulonephritis share pathogenic, pathological, and clinical features. They all involve capillaries, venules, arterioles, and small arteries. Approximately 90% of patients have autoantibodies either to myeloperoxidase (MPO-ANCA) or to proteinase 3 (PR3-ANCA). The clinical manifestations of ANCA-small vessel vasculitis are protean. These can be limited to the kidney alone, or may involve the upper respiratory tract, the lungs, the skin, or a number of other organs in various combinations. The characteristic feature of the glomerular lesion is a focal necrotizing glomerulonephritis associated with crescent formation and little or no glomerular staining for immunoglobulin by immunofluorescence microscopy. The renal manifestations can present as a rapidly progressive glomerulonephritis or that of a more indolent, remitting, and relapsing course that leads to substantial glomerulosclerosis. The two main prognostic markers of the long-term outcome are the presence of pulmonary hemorrhage (which accounts for at least half of all deaths) and the entry serum creatinine. The higher the entry serum creatinine, the higher the risk of developing end-stage renal disease. The treatment of ANCA-small vessel vasculitis and glomerulonephritis rests primarily on the use of induction high-dose corticosteroids and cyclophosphamide. Patients with pulmonary hemorrhage also benefit from plasmapheresis. With the use of an alkylating agent, the rate of remission is of the order of 75%, but relapses occur in about 30% of patients who achieve a remission, and in about 17% of patients after renal transplantation. Despite the improved outcome of patients with ANCA vasculitis in the recent decade, their long-term prognosis continues to be primarily determined by a rapid diagnosis, and the prompt institution of therapy.

Effect of ACE inhibitors in diabetic and nondiabetic chronic renal disease: a systematic overview of randomized placebo-controlled trials

Clinical trials have shown the beneficial effects of angiotensin-converting enzyme (ACE) inhibitors in delaying the progression of diabetic renal disease. There is less evidence from primary clinical trials of nondiabetic renal disease. We performed an updated meta-analysis to determine the efficacy of ACE inhibitors in slowing the progression of renal disease over a broad range of functional renal impairment. We included published and unpublished randomized, placebo-controlled, parallel trials with at least 1 year of follow-up available from January 1970 to June 1999. In nine trials of subjects with diabetic nephropathy and microalbuminuria, the relative risk for developing macroalbuminuria was 0.35 (95% confidence interval [CI], 0.24 to 0.53) for individuals treated with an ACE inhibitor compared with placebo. In seven trials of subjects with overt proteinuria and renal insufficiency from a variety of causes (30% diabetes, 70% nondiabetes), the relative risk for doubling of serum creatinine concentration or developing end-stage renal disease was 0.60 (95% CI, 0.49 to 0.73) for individuals treated with an ACE inhibitor compared with placebo. Treatment of individuals with chronic renal insufficiency with ACE inhibitors delays the progression of disease compared with placebo across a spectrum of disease causes and renal dysfunction.

Antineutrophil cytoplasmic antibodies and associated diseases: a review of the clinical and laboratory features

There have been a number of recent advances in this field. First, the "International Consensus Statement on Testing and Reporting of Antineutrophil Cytoplasmic Antibodies (ANCA)" has been developed to optimize ANCA testing. It requires that all sera are tested by indirect immunofluorescent (IIF) examination of normal peripheral blood neutrophils and, where there is positive fluorescence, in enzyme-linked immunosorbent assays (ELISAs) for antibodies against both proteinase 3 (PR3) and myeloperoxidase (MPO). Testing will be further improved when international standards and common ELISA units are available. Second, new diagnostic criteria for the small vessel vasculitides that take into account ANCA-positivity and target antigen specificity as well as histologic features are currently being produced. Third, we understand that the complications associated with treatment of the ANCA-associated vasculitides are often more hazardous than the underlying disease, and regimens that use effective but less toxic agents are being evaluated. The factors associated with increased risk of relapse, however, remain incompletely understood. Finally, ANCA with specificities other than PR3 and MPO are present in many nonvasculitic autoimmune diseases. Their clinical significance is still largely unclear, and some of the target antigens are present in other cells as well as neutrophils and thus are not strictly "ANCA."

Future molecular approaches to the diagnosis and treatment of glomerular disease

Current diagnoses and treatment decisions for renal disease are made based upon a combination of clinical and pathological determinations. With the advances in both biochemical and molecular biological techniques, identifying the underlying biochemical and genetic changes that may have initiated and/or contributed to the disease is possible. We describe here technologies that may lead to significant changes in renal disease diagnosis, characterization, treatment, and potentially prevention. For example, differential display techniques and DNA gene chip arrays show the changes in mRNA expression patterns and can potentially identify previously unknown genes and reveal new roles for previously known genes in renal disease. The generation of the single nucleotide polymorphisms (SNP) genomic map will facilitate genetic screening that may identify a gene or combination of genes that produce enhanced disease susceptibility. Combining genomic analysis with epidemiological studies may identify environmental factors that contribute to renal disease onset in genetically susceptible individuals. A number of novel therapies are already on the horizon. These include reagents that abrogate the function of specific cytokines, chemokines, and effector cells. With the list of renal disease genes in hand, their role in renal physiology and pathophysiology can be determined, which should lead to the discovery of pharmacological intervention directed at those genes and their products that play a role in the pathogenesis of renal disease.

Mycophenolate mofetil therapy in lupus nephritis: clinical observations

Controlled clinical trials in renal transplantation have demonstrated that mycophenolate mofetil is well tolerated and has lower renal transplant rejection rates than azathioprine regimens. This study reports on the clinical experiences at two institutions with mycophenolate mofetil (MMF) for severe lupus nephritis. Twelve patients with relapsing or resistant nephritis previously treated with cyclophosphamide therapy and one patient who refused cyclophosphamide as initial therapy for diffuse proliferative nephritis but accepted MMF were included. During combined MMF/prednisone therapy, serum creatinine values remained normal or declined from elevated values: mean change in serum creatinine was -0.26+/-0.46 microM/L, P = 0.039. Proteinuria significantly decreased: mean change in urine protein-to-creatinine ratios was -2.53+/-3.76, P = 0.039. Decreased serum complement component C3 and elevated anti-double-stranded DNA antibody levels at baseline improved in some, but not all, patients. The mean initial dose of MMF was 0.92 g/d (range, 0.5 to 2 g/d). The mean duration of therapy was 12.9 mo (range, 3 to 24 mo). Adverse events included herpes simplex stomatitis associated with severe leukopenia (n = 1), asymptomatic leukopenia (n = 2), nausea/ diarrhea (n = 2), thinning of scalp hair (n = 1), pancreatitis (n = 1), and pneumonia without leukopenia (n = 1). Recurrence of the pancreatitis led to discontinuation of MMF in this patient; all other adverse events resolved with dose reduction. It is concluded that MMF is well tolerated and has possible efficacy in controlling major renal manifestations of systemic lupus erythematosus. Controlled clinical trials are needed to define the role of MMF in the management of lupus nephritis.

International Consensus Statement on Testing and Reporting of Antineutrophil Cytoplasmic Antibodies (ANCA)

Antineutrophil cytoplasmic antibody (ANCA) tests are used to diagnose and monitor inflammatory activity in the primary systemic small vessel vasculitides. ANCA is best demonstrated in these diseases by using a combination of indirect immunofluorescence (IIF) of normal peripheral blood neutrophils and enzyme-linked immunosorbent assays (ELISAs) that detect ANCA specific for proteinase 3 (PR3) or myeloperoxidase (MPO). For ANCA testing in "new" patients, IIF must be performed on all serum samples. Serum samples containing ANCA, any other cytoplasmic fluorescence, or an antinuclear antibody (ANA) that results in homogeneous or peripheral nuclear fluorescence then should be tested in ELISAs for PR3-ANCA and MPO-ANCA. Optimally, ELISAs for PR3-ANCA and MPO-ANCA should be performed on all serum samples. Inclusion of the most recent positive sample in the IIF or ELISA may help demonstrate a change in antibody level. Reports should use recommended terms. Any report of positive neutrophil fluorescence issued before the ELISA results are available should indicate that positive fluorescence alone is not specific for the diagnosis of Wegener granulomatosis or microscopic polyangiitis and that decisions about treatment should not be based solely on the ANCA results.

Diagnostic usefulness of antineutrophil cytoplasmic autoantibody serology. Comparative evaluation of commercial indirect fluorescent antibody kits and enzyme immunoassay kits

Antineutrophil cytoplasmic autoantibodies (ANCAs) are increasingly used as serologic markers for pauci-immune crescentic glomerulonephritis and small vessel vasculitis. Many hospital laboratories and referral laboratories use commercial assay kits to detect ANCAs, despite inadequate documentation in the medical literature of kit performance. We evaluated the diagnostic sensitivity, specificity, and predictive value of 3 commercial indirect immunofluorescence assay (IFA) kits and 7 commercial enzyme immunoassay (EIA) kits for several ANCA subtypes. Serum samples from 396 patients with a variety of renal diseases were analyzed, including 146 patients with pauci-immune crescentic glomerulo-nephritis with or without systemic vasculitis. With 1 exception, the kits had more than 90% agreement with the reference standard and gave results similar to those of research laboratories. IFA diagnostic sensitivity ranged from 81% to 91% and EIA sensitivity from 75% to 84%. Maximum specificity was obtained with combined IFA and EIA. Diagnostic specificity was more than 70% for 2 of 3 IFA kits and at least 90% for 5 of 7 EIA kits. Predictive values varied with clinical manifestations. Most commercial IFA and EIA kits that were evaluated provide acceptably accurate analytic results.

Immunosuppressive therapy of lupus nephritis

Aggressive immunosuppressive therapy should be considered for patients with proliferative lupus nephritis as the risk for progression to end stage renal disease is high. Intermittent intravenous cyclophosphamide therapy improves renal survival; longer duration of therapy is associated with fewer relapse of nephritis and decreased risk of diminished renal function. While azathioprine therapy does not differ statistically from steroids alone in prolonging renal survival, this therapy may be considered in patients with few risk factors for progression to renal insufficiency. Methylprednisolone as a single therapy does not prolong renal survival compared with regimens including cyclophosphamide. Plasmapheresis remains under study but has not shown additional benefit in treatment of severe lupus nephritis. The potential roles for cyclosporin A and mycophenylate mofetil in the therapy of proliferative lupus nephritis remain to be defined. Supportive care including rigorous control of hypertension, consideration of angiotensin receptor inhibition or blockade to reduce proteinuria and prolong renal function, control of hyperlipidemia, prevention of osteoporosis, and prevention of pregnancy remain important clinical goals. Current research efforts focus on genetic and socioeconomic factors involved in racial differences in expression of lupus nephritis, hormonal manipulation to preserve gonadal function during cyclophosphamide therapy, and the potential impact on lupus activity of estrogen-containing oral contraceptives or postmenopausal hormone replacement therapy.

Efficacy of treatment for unexplained infertility

OBJECTIVE

To analyze the efficacy and cost-effectiveness of alternative treatments for unexplained infertility.

DESIGN

Retrospective analysis of 45 published reports.

SETTING

Clinical practices.

PATIENT(S)

Couples who met criteria for unexplained infertility. Women with Stage I or Stage II endometriosis were included.

INTERVENTION(S)

Observation; clomiphene citrate (CC); gonadotropins (hMG); IUI; and GIFT and IVF.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rate.

RESULT(S)

Combined pregnancy rates per initiated cycle, adjusted for study quality, were as follows: no treatment = 1.3%-4.1%; IUI = 3.8%; CC = 5.6%; CC + IUI = 8.3%; hMG = 7.7%; hMG + IUI = 17.1%; IVF = 20.7%; GIFT = 27.0%. The estimated cost per pregnancy was $10,000 for CC + IUI, $17,000 for hMG + IUI, and $50,000 for IVF.

CONCLUSION(S)

Clomiphene citrate + IUI is a cost-effective treatment for unexplained infertility. If this treatment fails, hMG + IUI and assisted reproduction are efficacious therapeutic options.

Interleukin-8 delays spontaneous and tumor necrosis factor-alpha-mediated apoptosis of human neutrophils

During inflammation, polymorphonuclear neutrophils (PMN) are exposed to and influenced by various cytokines, including the chemoattractant interleukin-8 (IL-8). We tested the hypothesis that IL-8 affects apoptosis in PMN. We investigated which IL-8 receptor (RI or RII) might be involved, as well as the role of Bcl-2. Human PMN were isolated and cultured up to 30 hours. Apoptosis was detected by UV and light microscopy, as well as by DNA-fragmentation assay, and quantitated by flow cytometry. Interleukin-8 significantly delayed spontaneous apoptosis at 10, 20, and 30 hours in a dose-dependent fashion. Polymorphonuclear neutrophil treatment with the highest concentration of IL-8 (100 nM) decreased the percentage of apoptotic cells from 2.1 +/- 1.5 to 0.8 +/- 0.2 after 10 hours, from 31 +/- 14 to 8 +/- 5 after 20 hours, and from 47 +/- 15 to 18 +/- 8 after 30 hours of incubation (P < 0.05 for all time points, N = 6). Interleukin-8 also inhibited TNF alpha-mediated PMN apoptosis. Incubation with 20 ng/ml TNF alpha resulted in 23 +/- 6% apoptotic cells at four hours, whereas pretreatment with IL-8 (50 nM) decreased this percentage to 11 +/- 3 (N = 5, P < 0.05). We next studied the role of both types of IL-8 receptors, RI and RII, by comparing the effect of IL-8 and the product of growth-related oncogene alpha (Gro alpha) on PMN cultured for 20 hours. Both IL-8 and Gro alpha attenuated apoptosis, although IL-8 was more effective than Gro alpha. Bcl-2 was detected by intracellular fluorescent antibody cell sorter analysis, Western blot, and reverse transcription-polymerase chain reaction (RT-PCR). Neither resting PMN nor IL-8-treated neutrophils expressed BCL-2 protein, which was readily detected in control cells. Furthermore, we could not detect BCL-2 gene expression by RT-PCR. We conclude that IL-8 prolongs the lifespan of human neutrophils in vitro by delaying apoptosis. This effect may be important for a controlled and effective inflammatory response. The delay in apoptosis can be mediated by the IL-8 RII, while RI may provide an added effect. The actions of IL-8 on apoptosis are Bcl-2 independent.

Neutrophil superoxide release is required for spontaneous and FMLP-mediated but not for TNF alpha-mediated apoptosis

Polymorphonuclear leukocyte (PMN) lifespan is characterized by both rapid production and apoptotic cell death. The mechanisms triggering apoptosis in PMN are not completely understood. In this study, the relationship of neutrophil activation and apoptosis as related to released superoxide was investigated. PMN apoptosis was detected by DNA fragmentation, and ultraviolet and light microscopy, and was quantified by flow cytometry; superoxide release was measured by superoxide dismutase-inhibitable reduction of ferricytochrome C. Incubation of PMN with 20 ng/ml tumor necrosis factor (TNF)alpha induced superoxide release (8.8 +/- 7.5 nmol O2-/30 min, n = 7) in normal PMN and also resulted in apoptosis within 2 h, whereas a subactivating dose of 2 ng/ml TNF alpha, which did not trigger superoxide release (3.1 +/- 1.7 nmol O2-, n = 10), did facilitate apoptosis, although to a lesser degree. PMN cultured under nonstimulating conditions underwent apoptotic cell death after 8 h. Exogenous superoxide dismutase did not inhibit apoptosis induced by 20 ng/ml TNF alpha. No upregulation of endogenous manganese superoxide dismutase mRNA expression was observed in response to TNF alpha as measured by reverse transcription PCR. Formyl-methionyl-leucyl-phenylalanine (FMLP) stimulation (10(-7) M) resulting in superoxide release of 31.7 +/- 6.1 nmol O2-/30 min (n = 10) also significantly increased the percentage of apoptosis, but at 24 h (P < 0.05). Exogenous superoxide dismutase did inhibit FMLP-induced apoptosis, as well as apoptosis due to aging in culture. In conclusion, aging and FMLP-stimulated PMN undergo apoptosis by a superoxide release-dependent pathway, whereas TNF alpha-facilitated apoptosis appears to be unrelated to respiratory burst oxidase activity.

Diagnosis and management of glomerular diseases

Glomerular diseases are a diagnostic challenge. Early recognition and timely institution of appropriate treatment are critical to optimum outcome in many patients, especially those with rapidly progressive glomerulonephritis. The clinical presentations and laboratory data provide adequate presumptive diagnoses in some patients; however, renal biopsy evaluation is often required for a definitive diagnosis.

Crosslinking of ANCA-antigens stimulates superoxide release by human neutrophils

Anti-neutrophil cytoplasmic antibodies (ANCA) activate primed human polymorphonuclear neutrophils (PMN) in vitro, resulting in a respiratory burst and degranulation. In this study, the hypotheses that the initiation of this process requires engagement of the F(ab')2 portion of ANCA, and that crosslinking of ANCA target antigens is necessary to trigger superoxide (O2-) release, were explored. It is speculated that Fc gamma receptor engagement is a modulator of ANCA-mediated activation. Flow cytometry demonstrated that intact human ANCA immunoglobulin (Ig), their corresponding F(ab')2 and Fab fragments, as well as a murine monoclonal to human PR3 and its F(ab')2 fragment, bind to ANCA antigens on the surface of PMN primed with tumor necrosis factor (TNF) alpha. Intact Ig of patients with PR3-ANCA or with MPO-ANCA stimulate O2- release from TNF alpha-primed normal PMN (2.6 +/- 3.57 to 15.3 +/- 7.39 nmol O2-/2.5 x 10(6) PMN/30 min). Corresponding F(ab')2 fragments result in similar O2- production (10.2 +/- 4.34 to 36.9 nmol) in a dose-dependent manner. ANCA Fab fragments do not stimulate O2- generation until these fragments are crosslinked with F(ab')2 of goat anti-human Ig F(ab')2, or when fragments are biotinylated and crosslinked with avidin. In contrast with these human autoantibody data, a mouse monoclonal anti-human PR3 antibody (25.7 +/- 8.55 nmol O2-), but not its corresponding F(ab')2 fragment, activates TNF alpha-treated human PMN. When the Fc gamma IIa receptors were blocked, superoxide production was reduced by 33% using human PR3-ANCA Ig (P < 0.05). In conclusion, PMN activation by ANCA occurs when intact ANCA or ANCA F(ab')2 fragments crosslink target antigens on the neutrophil cell surface. ANCA F(ab') fragments result in PMN activation when crosslinked by secondary reagents.

Comparison of measures for prospective identification of venous stenoses

OBJECTIVE

To compare two methods, venous dialysis pressure (VDP) and intra-access static flow pressure (VPO), for the prospective identification of venous stenoses in high-risk PTFE grafts.

DESIGN

Comparative.

SAMPLE/SETTING

Twenty patients with upper extremity loop grafts in an outpatient chronic hemodialysis population.

METHODS

VDP and VPO were measured for three consecutive treatments within subjects followed by angiography. VDP > 150 mmHg/200 ml/min, VPO > 0.40, and stenoses > 50% were considered positive findings.

RESULTS

In paired t-tests, VPO identified elevated venous pressure more frequently than VDP in patients positive on angiography (mean difference = 77.8%, p < 0.0001). Frequency analysis yielded a sensitivity of 36% for VDP and 93% for VPO (p < 0.05).

CONCLUSION

This study found that while VDP is the simpler method to use, VPO is significantly more accurate at predicting venous stenoses.

Apoptosis of endothelial cells induced by the neutrophil serine proteases proteinase 3 and elastase

The pathogenesis of vasculitis associated with anti-neutrophil cytoplasmic antibodies is not established. The anti-neutrophil cytoplasmic antibody autoanigens proteinase 3 (PR3) and elastase induce detachment and cytolysis of endothelial cells in vitro. We investigated whether PR3 and elastase trigger endothelial cell apoptosis. Primary bovine pulmonary artery endothelial cells were treated with either PR3, elastase, or myeloperoxidase (MPO) and apoptosis assessed by four different methods. By the cell death detection enzyme-linked immunosorbent assay, DNA fragmentation increased to 208 +/- 84% or 153 +/- 27% of control with 1 micrograms/ml PR3 or elastase at 24 hours. By ultraviolet light microscopy, the percentage of apoptotic cells significantly increased (P < 0.05) with 5 or 10 micrograms/ml PR3 and 25 or 50 micrograms/ml elastase at 6, 12, or 24 hours. Values at the 24-hour time point are 15.3 +/- 6.4% or 25.8 +/- 6.6% for 5 or 10 micrograms/ml PR3 and 13.9 +/- 3.6% or 20.7 +/- 1.8% for 25 or 50 micrograms/ml elastase compared with 2.2 +/- 1.2% for control. Similarly, with flow cytometry, 5 or 10 micrograms/ml PR3 and 25 or 50 micrograms/ml elastase for 6, 12, or 24 hours demonstrated increasing apoptosis in a dose- and time-dependent manner with the highest values achieved at 24 hours (23.4 +/- 4.0% and 35.6% for 5 and 10 micrograms/ml PR3 and 31.8 +/- 4.0% and 47.8% for 25 and 50 micrograms/ml elastase compared with 7.9 +/- 2.2% in control). Typical DNA laddering was apparent from 6 to 24 hours at 5 or 10 micrograms/ml PR3 and 25 or 50 micrograms/ml elastase. Myeloperoxidase did not induce cell apoptosis. Release of PR3 and elastase by activated neutrophils during acute inflammation, including anti-neutrophil cytoplasmic antibody-associated vasculitis, may result in vascular damage by endothelial cell apoptosis.

Disposition of didanosine in HIV-seropositive patients with normal renal function or chronic renal failure: influence of hemodialysis and continuous ambulatory peritoneal dialysis

OBJECTIVE

To evaluate the pharmacokinetics of didanosine in patients with normal kidney function or chronic kidney failure.

METHODS

Three groups of patients with human immunodeficiency virus (HIV) infection were studied: group I, six men with normal kidney function (creatinine clearance > 90 ml/min/1.73 m2); group II, six men with chronic renal failure maintained on continuous ambulatory peritoneal dialysis (CAPD); and group III, four men and two women with chronic renal failure receiving hemodialysis three times a week. A 300 mg dose of didanosine was administered orally and intravenously according to a two-period randomized crossover design. Patients in group III were studied between hemodialysis sessions during the crossover periods. In addition, patients in group III were studied in a third period after administration of a 300 mg oral dose of didanosine 4 hours before hemodialysis.

RESULTS

After intravenous administration in group I, the mean (+/-SD) total clearance (CLT) was 13.0 +/- 1.6 ml/min/kg and the elimination half-life (t 1/2) was 1.56 +/- 0.43 hour. In groups II and III, the CLT decreased significantly to 3.4 +/- 1.2 and 3.2 +/- 1.2 ml/min/kg, respectively, whereas the t1/2 increased to 3.60 +/- 0.82 hours and 3.11 +/- 0.88 hours, respectively. The absolute bioavailability of didanosine in groups I, II, and III was 42% +/- 12%, 52% +/- 6%, and 38% +/- 11%, respectively, and did not differ significantly. CAPD had little effect on the removal of didanosine, whereas approximately 30% of the drug present in the body at the start of dialysis was eliminated by an average 3-hour dialysis session.

CONCLUSION

The clearance of didanosine is impaired in patients with chronic renal failure. To compensate, the dose and schedule of administration should be adjusted. It is recommended that one-fourth of the total daily dose of didanosine be administered once a day in this patient population.

Frequency of anti-bactericidal/permeability-increasing protein (BPI) and anti-azurocidin in patients with renal disease

The major subtypes of anti-neutrophil cytoplasmic antibodies (ANCA) detected by indirect immunofluorescence assay (IFA) are P-ANCA and C-ANCA. In patients with vasculitis, myeloperoxidase (MPO) is the major P-ANCA antigen and proteinase 3 (PR3) is the major C-ANCA antigen. BPI and azurocidin, which are also called 57-kD cationic antimicrobial protein (CAP 57) and 37-kD cationic antimicrobial protein (CAP 37), respectively, have been proposed as less frequent target antigens for C-ANCA and P-ANCA. In patients with renal disease, we determined the frequency of antibodies against BPI and azurocidin. By IFA on alcohol-fixed neutrophils, monoclonal and polyclonal anti-BPI antibodies produced a C-ANCA pattern, whereas rabbit anti-azurocidin antibody produced a P-ANCA pattern. By ELISA, sera from 229 P-ANCA-positive patients, 99 C-ANCA-positive patients and 48 ANCA-negative (by IFA) patients with renal biopsies were tested for reactivity with recombinant human BPI and purified human azurocidin. Of these sera, 17.5% of P-ANCA, 30.3% of C-ANCA and 20.8% of IFA-ANCA-negative sera were positive for anti-BPI; and 8.3% of P-ANCA, 3.0% of C-ANCA and 8.3% of IFA-ANCA-negative sera were positive for anti-azurocidin. There was no statistical difference in frequency of anti-BPI between pauci-immune necrotizing and crescentic glomerulonephritis (NCGN) and other glomerular disease (OGD), and there was a lower frequency of anti-azurocidin in NCGN samples than in OGD samples. By Western blot, anti-BPI-positive sera reacted with a 57-kD BPI band and anti-azurocidin-positive sera with a 29-kD azurocidin band. In conclusion, there is a low frequency of anti-BPI and anti-azurocidin antibodies in ANCA-positive patient sera; however, this does not correlate with NCGN, which is a marker for ANCA-associated small vessel vasculitis, and a similar positivity is found in IFA-ANCA-negative patients with renal disease. Therefore, serologic detection of anti-BPI and anti-azurocidin is not diagnostically specific in patients with renal disease.

Wegener's granulomatosis mimicking a sternal abscess

Bone destruction as a manifestation of Wegener's granulomatosis has been reported, but these cases were limited to the head and face. We present a case in which a sternal abscess was the initial manifestation of Wegener's granulomatosis. We believe this is the first reported case of bone destruction due to Wegener's occurring in a location other than the head and face.