POS0829 SPECTRUM OF ANCA-SPECIFICITIES IN EOSINOPHILIC GRANULOMATOSIS WITH POLYANGIITIS IN A RETROSPECTIVE MULTICENTER STUDY

Background

Anti-neutrophil cytoplasmic autoantibodies specific for myeloperoxidase (MPO-ANCA) are found in 10-70% of the patients with eosinophilic granulomatosis with polyangiitis (EGPA) depending on disease activity, methodological aspects and cohort examined [1-3]. Recently, a higher prevalence of anti-pentraxin 3 (PTX3)-ANCA has been reported in EGPA compared to granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) [4].

Objectives

To investigate the spectrum of ANCA specificities in a multicenter cohort of patients with EGPA and identify novel ANCA antigens.

Methods

We conducted a retrospective analysis of 73 patients with EGPA treated between 2015 and 2020 in 3 tertiary referral centers. In addition to in-house ANCA testing with indirect immunofluorescence (IFT) on fixed human granulocytes and antigen-specific enzyme-linked immunosorbent assays (ELISA), ANCA specificities were determined using a cell-based assay (CBA; Euroimmun, Lübeck, Germany). Diagnosis was based on Chapel Hill consensus conference definitions, ACR- and MIRRA-criteria for EGPA. Patient characteristics and clinical manifestations were evaluated and compared based on ANCA status. Fisher`s exact test was employed for comparison of patient groups.

Results

ANCA findings are summarized in Table 1. MPO- and proteinase 3 (PR3)-ANCA positive patients (13.7%) had a higher prevalence of peripheral neuropathy (70% vs. 44.4%, p = 0.0003) and glomerulonephritis (20% vs. 14.3%, not significant). MPO- and PR3-ANCA-negative patients (86.3%) had a higher prevalence of heart (10% vs. 46%, p <0.0001), central nervous system (CNS) (0% vs. 14.3%, p <0.0001) and gastrointestinal (10% vs. 22.2%, p = 0.0327) involvement. PTX3-ANCA were associated with a higher prevalence of ear-nose-throat (ENT) (100% vs. 85.3%, p <0.0001), lung (100% vs. 89.7%, p = 0.0015), gastrointestinal involvement (60% vs. 17.6%, p <0.0001) and peripheral neuropathy (100% vs. 48.5%, p <0.0001). Kidney (0% vs. 16.2%, p <0.0001) and CNS involvement (0% vs. 13.2%, p = 0.0002) occurred less frequently in PTX3-ANCA positive patients. The 2 olfactomedin 4 (OLM4)-ANCA positive patients presented with ENT, lung and kidney involvement, and polyneuropathy, respectively.

Table 1.

ANCA in EGPA cohort (n = 73). BPI = bactericidal permeability-increasing protein.

IFT / ELISANo. of patients (%)P-ANCA11 (15.1)C-ANCA5 (6.8)MPO-ANCA8 (10.9)PR3-ANCA2 (2.7)BPI-ANCA1 (1.4)PTX3-ANCA5 (6.8)OLM4-ANCA2 (2.7)

Conclusion

We report on the detection of PTX3-, BPI- and OLM4-ANCA in addition to MPO- and PR3-ANCA in EGPA. OLM4-ANCA has been reported in 2 patients with non-vasculitic inflammatory symptoms previously [5]. Herein, detection of OLM4-ANCA in EGPA is reported for the first time. Our study shows that the presence of ANCA with various specificities other than MPO and PR3 contribute to a higher prevalence of ANCA in EGPA. Moreover, clinical manifestations differ between ANCA-negative EGPA and ANCA-positive EGPA, and between patients with different ANCA-specificities.

References

[1]Schönermarck U, et al. Prevalence and spectrum of rheumatic diseases associated with proteinase 3-antineutrophil cytoplasmic antibodies (ANCA) and myeloperoxidase-ANCA. Rheumatology 2001;40:178-84.

[2]Bremer P, et al. Getting rid of MPO-ANCA: a matter of disease subtype. Rheumatology 2013:752-4.

[3]Comarmond C, et al. Eosinophilic granulomatosis with polyangiitis (Churg-Strauss): clinical characteristics and long-term followup of the 383 patients enrolled in the French Vasculitis Study Group cohort. Arthritis Rheum 2013;65:270-81.

[4]Padoan R, et al. IgG anti-Pentraxin 3 antibodies are a novel biomarker of ANCA-associated vasculitis and better identify patients with eosinophilic granulomatosis with polyangiitis. J Autoimmun 2021;124:102725.

[5]Amirbeagi F, et al. Olfactomedin-4 autoantibodies give unusual c-ANCA staining patterns with reactivity to a subpopulation of neutrophils. J Leukoc Biol 2015;97:181-9.

Disclosure of Interests

None declared

Utility of serum complement factors C3 and C4 as biomarkers during therapeutic management of giant cell arteritis

OBJECTIVE

There is a strong unmet need for biomarkers in giant cell arteritis (GCA), as C-reactive protein (CRP) may be unreliable in patients treated with Tocilizumab (TCZ). We aimed to assess whether C3 and C4 are useful biomarkers in GCA patients, particularly in those treated with TCZ.

METHOD

We retrospectively enrolled all patients who underwent C3 and C4 measurement at baseline. All patients were evaluated at 3, 6, 12, and 24 months after diagnosis, as part of routine follow-up. Two assessments after the end of the observational period, in case of further relapses, were also included.

RESULTS

At baseline, mean ± sd levels (mg/dL) of C3 (133 ± 28.99) and C4 (25.9 ± 9.04) were within normal ranges. During follow-up, C3 and C4 decreased in patients attaining remission (107.07 ± 19.86, p = 0.0006; 19.86 ± 10.27, p = 0.01, respectively) and sustained remission (95.85 ± 18.04, p = 0.001; 15.61 ± 9.75, p = 0.006). In TCZ-treated patients, even stronger decreases in C3 (83.11 ± 19.66, p = 0.001) and C4 (8.26 ± 3.83, p < 0.0001) were observed, and their values were not correlated with CRP or erythrocyte sedimentation rate.

CONCLUSION

C3 and C4 do not seem useful in the diagnosis of GCA, as normal values do not rule out active vasculitis. However, C3 and C4 correlate with disease activity. As the low C4 levels found in TCZ-treated patients are not correlated with CRP, C4 should be evaluated as a potential biomarker of disease activity and treatment response.

[Paradigm shift in ANCA diagnostics : New international consensus recommendations]

BACKGROUND

Up to now indirect immunofluorescence (IIF) followed by an antigen-specific assay specific for proteinase 3 (PR3) or myeloperoxidase (MPO) has been the standard method for the detection of antineutrophil cytoplasmic antibodies (ANCA). The development of more sensitive and highly specific PR3-ANCA and MPO-ANCA immunoassays for the diagnosis of ANCA-associated vasculitis (AAV) has raised doubts about the two-stage diagnostic strategy currently recommended for ANCA detection.

OBJECTIVE

Presentation and discussion of the new international consensus recommendations on ANCA testing in AAV.

METHODS

This article presents the new guidelines for ANCA testing that have been developed based on the results of a recent large multicenter study by the European Vasculitis Society (EUVAS). The draft of the author committee was revised by each contributor and subsequently distributed to 12 experts on 4 continents. After further revision the final document was returned for ratification and submitted for publication.

RESULTS/CONCLUSION

The current study results confirm the superiority of the diagnostic value of antigen-specific immunoassays compared to IIF. The current consensus recommendations support the primary use of PR3-ANCA and MPO-ANCA immunoassays for diagnostic evaluation of patients with AAV without the categorical need for additional IIF.

Diagnostic Value of Procalcitonin in ANCA-Associated Vasculitis (AAV) to Differentiate Between Disease Activity, Infection and Drug Hypersensitivity

Objective:

Procalcitonin (PCT) is considered to be a specific marker for severe bacterial infections and sepsis. Elevated PCT levels have been reported in active autoimmune diseases without infection.

The aim of this study was to assess the diagnostic value of PCT serum levels in ANCA-associated vasculitis (AAV) patients with respect to infection, disease activity and drug fever using a high sensitive PCT detection method.

Methods:

In 53 AAV patients with elevated C-reactive protein (CRP) PCT was determined by the Thermo Scientific BRAHMS PCT sensitive KRYPTOR assay. Patients underwent standardized diagnostic procedures for evaluation of disease activity and infection.

Results:

53 patients with AAV and elevated CRP (7.7±6.9 mg/dl, PCT 0.34±1.02 ng/ml) were assessed, 10 had infection with elevated CRP levels of 11.2±10.2 mg/dl and PCT levels of 1.06±2.07 ng/dl. 43 patients had no evidence of infection, 36 of them were presented with AAV with normal or only slightly positive PCT levels in active disease (n=36) (PCT 0.06±0.06 ng/ml). 7 patients had increased PCT levels due to azathioprine hypersensitivity (0.76±1.01 ng/ml). For discrimination between infection and vasculitis activity PCT was more useful than CRP with the best cut-off at 0.1 ng/ml (sensitivity 60%, specificity 92%).

Conclusion:

In contrast to previous studies using semiquantitative PCT assays, the KRYPTOR performs better with respect to discrimination of infection from active AAV. In all patients assessed with active AAV (and without infection) PCT levels remained below the PCT reference limit (0.5 ng/ml) for infections. Drug hypersensitivity seems to be an important differential diagnosis in the setting of elevated CRP and PCT in patients who receive azathioprine.

Correlation of serum level of high mobility group box 1 with the burden of granulomatous inflammation in granulomatosis with polyangiitis (Wegener's)

OBJECTIVES

To investigate the correlation of serum levels of high mobility group box 1 (HMGB1) with the extent of granulomatous inflammation in granulomatosis with polyangiitis (GPA).

METHODS

From 169 patients with GPA, 17 patients with granulomatous inflammation, without evidence of vasculitis were identified and 36 patients without measurable 'granuloma' formation. HMGB1 serum levels were determined and compared between the two groups, using a Mann-Whitney U test. Serum levels of 26 healthy individuals served as controls. In a further 21 patients with GPA with a pulmonary granulomatous manifestation from the study population, CT volumetry of 'granuloma' was performed. Volumes were compared with serum levels of HMGB1 (Spearman rank order test).

RESULTS

Serum levels of HMGB1 were significantly higher in patients with predominant granulomatous disease than in patients without measurable 'granuloma' manifestations (6.44 ± 4.53 ng/ml vs 3.85 ± 2.88 ng/ml; p=0.0107). In both groups, levels of HMGB1 were significantly higher than in controls (2.34 ± 2.01 ng/ml; p<0.01). A positive correlation of HMGB1 serum levels with volumes of pulmonary 'granuloma' (r=0.761, p<0.0017) was seen.

CONCLUSIONS

HMGB1 serum levels are significantly higher in GPA with predominant granulomatous manifestations and correlate with volumes of pulmonary 'granuloma'. HMGB1 may be used as a marker of the burden of granulomatous inflammation in GPA.

Proteinase 3, protease-activated receptor-2 and interleukin-32: linking innate and autoimmunity in Wegener's granulomatosis

Proteinase 3 (PR3) is a multifunctional neutrophil-derived serine protease influencing cell cycle, differentiation, and cell death. This molecule is the main target antigen of autoantibodies in Wegener's granulomatosis (WG) known as antineutrophil cytoplasmic antibodies (PR3-ANCA). WG usually starts as granulomatous inflammation of the upper respiratory tract (localized phase) and progress to systemic disease with PR3-ANCA-associated vasculitis (generalized phase). PR3-ANCA is thought to play a critical role in the pathogenesis of vascular damage in WG. In contrast, it is not clear how the granulomatous inflammation, the hallmark of WG, is driven, and what is the relationship between granuloma and autoimmunity. Recent findings provide evidence that PR3 might function as endogenous "danger/alarm" signal that communicates the presence of tissue injury to dendritic cells (DC) via protease-activated receptor-2 (PAR-2), triggers their maturation and instructs DC to induce Th1-type cell responses in WG. Furthermore, PR3 has the capacity to bind and activate IL-32, a recently discovered proinflammatory cytokine that has emerged as an important player in innate and adaptive immune response.Collectively, these results delineate new pathogenic pathways at the molecular level and provide insights into the mechanisms by which PR3 may contribute to the early pathogenesis of WG supporting the pivotal role of the interaction of Wegener's autoantigen with the "gateway" receptor PAR-2 in mediating both innate and adaptive immune response in WG.

Eotaxin-3 is involved in Churg-Strauss syndrome--a serum marker closely correlating with disease activity

OBJECTIVE

Churg-Strauss Syndrome (CSS) is characterized by excessive eosinophil accumulation in peripheral blood and affected tissues with development of granulomatous vasculitic organ damage. The contribution of eosinophil-chemotactic cytokines (eotaxin family) to eosinophilia and disease activity in CSS is unknown. Thus, we compared serum levels of the eotaxin family members in CSS patients with healthy and disease controls.

METHODS

Forty patients with CSS diagnosed according to ACR 1990 criteria, 30 healthy controls (HC) and 57 disease controls (28 asthma, 20 small vessel vasculitis, 9 hypereosinophilic syndrome) were studied. Clinical data were collected and serum levels of eotaxin-1, -2 and -3 were determined by ELISA. Further, immunohistochemistry was applied to identify eotaxin-3 expression in tissue biopsies from patients with CSS.

RESULTS

In contrast to eotaxin-1 and -2, eotaxin-3 was highly elevated in serum samples of active CSS patients and correlated highly significantly with eosinophil counts, total immunoglobulin E (IgE) levels and acute-phase parameters. Moreover, eotaxin-3 was not elevated in other eosinophilic and vasculitic diseases. Immunohistochemical analysis revealed strong expression of eotaxin-3 in endothelial and inflammatory cells in affected tissues of active CSS patients.

CONCLUSIONS

This study reveals the specific association of elevated eotaxin-3 expression with high disease activity and eosinophilia in CSS patients. Eotaxin-3 might thus be a pathogenic player, biomarker and potential therapeutic target in CSS.

Evaluation of the FIDIS Vasculitis Multiplex Immunoassay for Diagnosis and Follow-up of ANCA-Associated Vasculitis and Goodpasture's Disease

We have evaluated a new-multiplex immunoassay (FIDIS Vasculitis) for simultaneous detection and quantification of anti-MPO, -PR3, and -glomerular basement membrane (GBM) antibodies in diagnosis and follow-up of ANCA-associated vasculitides (AAV) and Goodpasture's disease. ANCA were determined in sera of (a) 87 consecutive patients with biopsy-proven pauci-immune NCGN and 72 controls; (b) 9 patients with Goodpasture's disease; and (c) 60 WG patients and 60 controls, previously used in a multicenter comparison of direct and capture ELISA for PR3-ANCA. Finally, for prediction of relapses, PR3-ANCA was measured in samples preceding relapse in 23 PR3-AAV patients and in 23 matched PR3-AAV patients without relapse. The relative sensitivity of the FIDIS Vasculitis assay was 97.4% for MPO-ANCA and 92.3% for PR3-ANCA; specificity was 100% and 97.2%, respectively. Evaluation of the anti-GBM antibody detection revealed a sensitivity of 100% and a specificity of 99.6%. The sensitivity for WG of the PR3-ANCA detection (71.6%) approached the performance of capture ELISA (74%), although at the cost of specificity (96.7% versus 100%). For prediction of relapses a rise of 50% in ANCA level by FIDIS Vasculitis appeared optimal (ROC curve) for prediction of relapses. However, as compared to capture ELISA, both positive (63% versus 76%) and negative (68% versus 72%) predictive values were reduced. In conclusion, simultaneous detection of anti-MPO, -PR3, and -GBM antibodies in the multiplex FIDIS Vasculitis assay has excellent performance in terms of diagnosis of patients with AAV or Goodpasture's disease. However, detection of rises in PR3-ANCA for prediction of relapses gives less optimal results when compared to capture ELISA.

A novel high sensitivity ELISA for detection of antineutrophil cytoplasm antibodies against proteinase-3

OBJECTIVE

Conventional direct enzyme-linked immunosorbent assays (ELISA) for the detection of anti-neutrophil cytoplasm antibodies (ANCA) often lack sensitivity because epitopes of the target antigen are hidden by binding to the ELISA plate. This study was designed to evaluate a novel ELISA method for detection of ANCA against proteinase-3 (PR3) for the diagnosis of Wegener's granulomatosis (WG) using PR3 presented in its native form.

METHODS

Sera from four subgroups of patients with a diagnosis of WG (n=86), 80 healthy controls and 450 disease controls were tested for the presence of C-ANCA/PR3-ANCA by anchor ELISA, direct ELISA, capture ELISA, indirect immunofluorescence (IFT) and immunoblotting.

RESULTS

In prospectively analysed consecutive patients, anchor ELISA showed the highest sensitivity for a diagnosis of WG of 96.0% (95% CI: 79.6-99.3), followed by IFT 92.0% (73.9-98.8), capture ELISA 72.0 (50.6-87.9) and direct ELISA 60.0 (38.7-78.8). Specificity was high for all methods and ranged from 98.5 (97.0-99.4) to 95.5% (97.9-99.8). Receiver operating characteristics curve analysis revealed that the overall diagnostic performance of the anchor ELISA was significantly superior compared to the direct ELISA and the capture ELISA in patients with generalized WG, and also compared to IFT and immunoblotting in patients with localised WG.

CONCLUSION

Anchor ELISA is a novel highly sensitive and specific method for the detection of PR3-ANCA in patients with WG, which may replace the need for a combined analysis with IFT and ELISA in the future.

Proinflammatory cytokines and autoimmunity in Churg-Strauss syndrome

Churg-Strauss syndrome (CSS) belongs to the antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides and is further characterized by severe eosinophilia and, often, granulomatous inflammation. The therapeutic efficacy of recombinant interferon-alpha (IFN-alpha) and tumor necrosis factor-alpha (TNF-alpha) blockade point toward a central role of cytokines in the pathogenesis of CSS. Recent data show that, in contrast to other primary systemic vasculitides, peripheral blood mononuclear cells (PBMCs) secrete not only large amounts of T helper type 1 (Th1) cytokines, particularly IFN-gamma, but also release T helper type 2 (Th2) cytokines such as interleukin-4 (IL-4) and interleukin-13 (IL-13). Interleukin-5 is the most potent stimulator of eosinophil production and functional activation of mature eosinophils, the key effector cells in CSS. Data are presented showing that PBMCs from patients with CSS cultured with T cell-specific stimuli secrete significantly increased amounts of IL-5 compared with healthy controls, suggesting that IL-5 contributes substantially to the development of eosinophilia in CSS. As recombinant IFN-alpha downregulates IL-5 production of CD4(+) T cells in vitro, the increased secretion of IL-5 in patients with CSS may provide the clue for the therapeutic efficacy of recombinant IFN-alpha in the disease. Variations in the balance between Th1 and Th2 cytokines at different disease stages could contribute to the distinct clinical courses seen in patients with CSS, which can range from prominent Th1-mediated generalized vasculitis and granulomatous inflammation on one end of the spectrum to Th2-mediated systemic hypereosinophilia on the other. Although the association of ANCAs with CSS point toward an autoimmune origin of the disease, there is no direct evidence as yet for a direct pathogenic role of ANCAs in CSS.

Variations in performance characteristics of commercial enzyme immunoassay kits for detection of antineutrophil cytoplasmic antibodies: what is the optimal cut off?

BACKGROUND

Previous studies have shown considerable variation in diagnostic performance of enzyme linked immunosorbent assays (ELISAs) for measuring antineutrophil cytoplasmic antibodies (ANCA) specific for proteinase 3 (PR3) and myeloperoxidase (MPO).

OBJECTIVE

To analyse the performance characteristics of different commercially available direct ANCA ELISA kits.

METHODS

ELISA kits for detecting PR3-ANCA and MPO-ANCA from 11 manufacturers were evaluated. Serum samples were taken from patients with Wegener's granulomatosis (15), microscopic polyangiitis (15), other vasculitides (10), and controls (40).

RESULTS

were compared with data obtained by indirect immunofluorescence (IFT). The diagnostic performance of the tests was analysed and compared by receiver operating characteristic (ROC) curve analysis.Results: Applying the manufacturers' cut off resulted in great variation in sensitivity of the commercial PR3-ANCA kits for diagnosing Wegener's granulomatosis (ranging from 13.3% to 66.7%), and of the MPO-ANCA kits for diagnosing microscopic polyangiitis (ranging from 26.7% to 66.7%). Specificities were relatively constant (from 96.0% to 100%). IFT was superior to all ELISAs (C-ANCA for Wegener's granulomatosis: sensitivity 73.3%, specificity 98%; P-ANCA for microscopic polyangiitis: sensitivity 86.7%, specificity 98%). The sensitivities of PR3-ANCA and MPO-ANCA ELISA kits were increased by lowering the cut off values. This reduced specificity but increased overall diagnostic performance.

CONCLUSIONS

The low sensitivity of some commercial kits reflects the high cut off levels recommended rather than methodological problems with the assays. Comparative analyses using sera from well characterised patients may help identify optimum cut off levels of commercial ANCA ELISA tests, resulting in better comparability of results among assays from different manufacturers.

Association study of Wegener granulomatosis and the functionally relevant A645G polymorphism in the bactericidal/permeability increasing protein (BPI) gene

In antineutrophil cytoplasmatic antibody (ANCA)-associated vasculitides (AAV), bactericidal/permeability increasing protein (BPI) ANCAs are detected. Recent observations suggest that BPI-ANCAs can potentially contribute to a proinflammatory setting in the absence of proteinase 3 (PRTN3) ANCAs during the development of a pulmonary relapse by impeding the elimination of Gram-negative bacteria (GNB). However, it is as yet not clear whether the genetic background contributes to the generation of BPI-ANCAs in Wegener granulomatosis (WG) or if BPI polymorphisms are associated with WG. In this study we genotyped the functionally relevant single nucleotide polymorphism (SNP) A645 (Glu216Lys) of the BPI gene in 201 WG patients and 608 healthy controls. To investigate whether further SNPs might be associated with WG, we also examined an intragenic microsatellite marker. No significant differences were found between patients and controls. Thus BPI polymorphisms do not appear to contribute to genetic predisposition to WG. Moreover, our data do not suggest a genetic background for the generation of BPI-ANCAs in WG.

Small vessel vasculitis and relapsing panniculitis in tumour necrosis factor receptor associated periodic syndrome (TRAPS)

CASE REPORTS

A 66 year old female patient had relapsing fever and non-suppurative panniculitis suggestive of enigmatic "Weber-Christian disease" (WCD). Antineutrophil cytoplasmic antibodies with specificity for human leucocyte elastase (HLE-ANCA) were detected. A biopsy showed small vessel vasculitis and panniculitis. A 53 year old man had recurrent episodes of abdominal pain, erythematous rash, and myalgia. Fever attacks had stopped a few years ago. A biopsy showed panniculitis and fasciitis. In both patients mutations (R92Q, T50M) of the tumour necrosis factor receptor super family (TNFRSF) 1A gene were disclosed. Mutations of the TNFRSF 1A gene are the cause of tumour necrosis factor receptor associated periodic syndrome (TRAPS). Both patients responded favourably to treatment with the human soluble p75 TNF alpha receptor fusion protein etanercept (2 x 25 mg subcutaneously/week).

DISCUSSION

Small vessel vasculitis and panniculitis have not been reported in TRAPS so far. The cases underline the importance of TNF alpha regulation in inflammatory processes including vasculitis. Genetically determined causes of fever may account for some cases of WCD.

Prevalence of ANCA in mixed cryoglobulinemia and chronic hepatitis C virus infection

OBJECTIVE

To determine the prevalence, target antigens and clinical associations of antineutrophil cytoplasmic antibodies (ANCA) in chronic hepatitis C without extrahepatic manifestations and in chronic hepatitis C virus (HCV)-associated mixed cryoglobulinemia (MC) in two European centers.

METHODS

50 sera from patients with chronic hepatitis C and 116 sera from HCV-associated MC were tested for cytoplasmic or perinuclear pattern (C-ANCA/P-ANCA) by indirect immunofluorescence test (IFT). ANCA target antigens were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Clinical characteristics of the patients were not different between the two centers. Cryoglobulinemic vasculitis (CV) was biopsy-proven in about 90% of the MC patients. Two patients with HCV-associated MC and 1 patient with chronic hepatitis C had a P-ANCA. A C-ANCA was detected in 1 patient with HCV-associated MC. Eight patients with a HCV-associated MC and 5 patients with chronic hepatitis C had an ANCA either directed against bactericidal/permeability increasing protein (BPI) or cathepsin G (CG). BPI- or CG-ANCA positivity was not associated with a more severe disease course. The C-ANCA titer followed disease activity in one C-ANCA positive HCV-associated MC patient. The subspecificity of the C-ANCA was not determinable in that patient.

CONCLUSION

Two new target antigens of ANCA have been identified in HCV-associated MC and chronic hepatitis C in this study. BPI-ANCA and GC-ANCA were present in about 10% of patients with HCV-associated MC or chronic hepatitis C. ELISA proved to be more sensitive in the detection of ANCA than IFT. The present study on chronic HCV infection adds to various reports on the induction of CG- and BPI-ANCA in chronic infections.

Update on the pathogenesis of Churg-Strauss syndrome

Churg-Strauss syndrome (CSS) is a rare form of systemic vasculitis occurring in patients with asthma. The cause of CSS is unknown, and yet little data are available regarding its pathogenesis. The presence of a marked tissue- and blood-eosinophilia, as well as secretory products of eosinophils in blood and tissues, implicates a pathogenetic role of eosinophil granulocytes. Prolonged survival of eosinophils due to inhibition of CD95-mediated apoptosis by soluble CD95 seems to contribute to eosinophilia in CSS. Although the mechanisms involved in eosinophil-activation in CSS have not been elucidated, recent data suggest a possible role of T lymphocytes secreting eosinophil-activating cytokines. This review describes the current insights into the pathogenesis of CSS in the light of its putative nature as a type 2 granulomatous disease. Recent clinical, experimental and epidemiologic data regarding the possible role of inflammatory cells and their secretory products, anti neutrophil cytoplasm antibodies (ANCA), epidemiologic factors and anti-asthma treatments are summarized.

ANCA against bactericidal/permeability-increasing protein, azurocidin, calprotectin and defensins in rheumatic and infectious diseases: prevalence and clinical associations

OBJECTIVE

To determine the prevalence and clinical associations of ANCA against the antibiotic proteins and peptides: Bactericidal/permeability-increasing protein (BPI), Azurocidin (AZ), Calprotectin (CP) and beta-Defensin-1 and -2 (DF).

METHODS

Patients with ANCA-associated vasculitides (n = 99), other vasculitides and rheumatic connective tissue diseases (n = 303), HIV-infection (n = 66), other infectious diseases (n = 134) Crohn's disease (n = 12) and ulcerative colitis (n = 12) were tested for BPI-, AZ-, CP-, DF-, PR3-, and MPO-ANCA in indirect immunofluorescence technique (IFT) and ELISA.

RESULTS

In ANCA associated vasculitides BPI-ANCA were detected in 6% of patients. In HIV infection, BPI was the main target antigen of ANCA-IFT positive sera (74%). BPI-ANCA was associated with higher inflammatory activity. In Crohn's disease and ulcerative colitis BPI-ANCA was prominent (34% of patients). AZ-ANCA were found in 5% of patients. No ANCA were detected against defensin and calprotectin.

CONCLUSION

BPI-ANCA is the main autoantibody in HIV and is associated with higher inflammatory activity. In inflammatory bowel diseases BPI-ANCA is predominant, AZ-ANCA are also present to a lesser extend. Both were not useful characterize clinical subgroups. No ANCA were detected against calprotectin or defensins.

A critical evaluation of commercial immunoassays for antineutrophil cytoplasmic antibodies directed against proteinase 3 and myeloperoxidase in Wegener's granulomatosis and microscopic polyangiitis

OBJECTIVE

To evaluate the performance of 11 commercial enzyme-linked immunosorbent assay (ELISA) kits for the detection of antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) and myeloperoxidase (MPO) in patients with Wegener's granulomatosis (WG) and microscopic polyangiitis (MPA).

METHODS

Serum samples were taken from 92 patients with a histological and clinical diagnosis of WG (n=50) or MPA (n=42) and from 30 disease controls (systemic lupus erythematosus, n=15; rheumatoid arthritis, n=15) and 30 healthy controls. Each of the sera was tested for the presence of ANCA directed against PR3 and MPO using 11 commercially available direct ELISA kits, our in-house PR3- and MPO-ANCA capture ELISAs, and the indirect immunofluorescence technique (IFT).

RESULTS

In tests for WG using PR3-ANCA, the commercial direct ELISA kits differed widely in their sensitivity (from 22 to 70%) and negative predictive value (NPV) (from 43 to 70%), but only moderately in their specificity (from 93 to 100%) and positive predictive value (PPV) (from 93 to 100%). The highest sensitivity (74%) and specificity (100%) for PR3-ANCA were obtained with the in-house capture ELISA. Similar differences and trends were noted for MPO-ANCA assays. Diagnostic sensitivity was more than 60% for four and at least 50% for six of the 11 ELISA kits. The PPV varied from 84 to 100% and the NPV from 58 to 70%. In tests for MPA, the MPO-ANCA ELISA kit designated F and the in-house capture ELISA were best (both had sensitivity 62% and specificity 100%). For both WG and MPA, maximum sensitivity for ANCA was obtained with IFT (80 and 70% respectively).

CONCLUSION

Determination of PR3-ANCA and MPO-ANCA with the commercial direct ELISA kits achieved poor sensitivity for both WG and MPA. The in-house PR3 and MPO-ANCA capture ELISAs performed better than the commercial ELISAs, combining higher specificity with similar sensitivity. IFT remains the best method for ANCA detection in both diseases.

[New aspects of antineutrophil cytoplasmic antibody (ANCA) diagnosis in vasculitis]

Anti-Neutrophil Cytoplasmic Antibodies (ANCA) are a heterogenous group of autoantibodies with a broad spectrum of clinically associated diseases. The diagnostic value is established of Proteinase 3 (PR3)-ANCA for Wegener's granulomatosis (WG) as well as Myeloperoxidase (MPO)-ANCA for microscopic polyangiitis (MPA). Within the last 20 years these antibodies were subject of intensive studies and a growing body of evidence arose for a distinct role of ANCA in the pathogenesis of the ANCA associated vasculitides WG and MPA. Our current concept of whether ANCA directly or indirectly contribute to vascular damage (ANCA-Cytokine-Sequence-Theory) was mainly developed from in vitro studies. It is plausible and it is supported by data from clinical investigations as well as animal models. Nevertheless our knowledge of the etiological and pathogenetic pathways remains incomplete.

Elevated monocytic IL-12 and TNF-alpha production in Wegener's granulomatosis is normalized by cyclophosphamide and corticosteroid therapy

Wegener's granulomatosis (WG) is characterized by a predominance of the type 1 T-helper cell (Th1) response. We have studied monocytic cytokine expression in untreated patients and in patients who did not respond to prior methotrexate or trimethoprim-sulphamethoxazole therapy, i.e. patients with active disease. Intracytoplasmic IL-12 and TNF-alpha expression was significantly increased in WG compared with healthy controls. IL-8 expression was not increased. Two and 12 weeks of daily standard oral cyclophosphamide and corticosteroid (CYC + GC) treatment induced a stable remission of the disease. Elevated IL-12 and TNF-alpha expression of monocytes was normalized. The active metabolite of CYC was shown to down-regulate IL-12 mRNA in vitro. Monocytic cytokines, especially IL-12, may have a role in the early determination and skewing of the immunoregulatory response towards a Th1 profile. It appears that CYC + GC exerts its effect by normalizing the Th1-driving cytokine pattern, and CYC may maintain this mode of action. Normalization of the skewed cytokine pattern may be a prerequisite and an indicator of inducing a remission in WG.

Increased expression of CTLA-4 (CD152) by T and B lymphocytes in Wegener's granulomatosis

CTLA-4 (CD152) is a surface molecule of activated T cells with sequence homology to CD28. Both molecules bind to the same ligands, B7.1 (CD80) and B7.2 (CD86) but have antagonistic functions. While CD28 is an important costimulator, CTLA-4 has an essential inhibitory function in maintaining the homeostasis of the immune system. Furthermore, CTLA-4 has a role in inducing a Th1 response and suppressing Th2 cytokines, an effect which is antagonized by CD28. Many autoimmune diseases are characterized by an overwhelming production of Th1 cytokines. Recently, the predominance of the Th1 cytokine pattern has been directly observed in the granulomatous inflammation of patients with Wegener's granulomatosis. The balance between CD28 and CTLA-4 expression by T lymphocytes could be a factor in the pathogenesis of autoimmune diseases. Down regulation of CD28 predominantly on CD8+ T cells has been described in Wegner's granulomatosis; however, analysis of CTLA-4 is complicated by its low expression levels. Here we have used potent signal enhancement to study CTLA-4 on PBMC in patients with Wegener's granulomatosis (n = 25) in comparison with healthy controls (n = 19). Expression levels of CTLA-4 were significantly increased selectively on CD4+ and possibly also on CD4-/CD8- T cells in Wegener's granulomatosis. High CTLA-4 expression by T lymphocytes was associated with more severe disease. In contrast, after stimulation with the mitogen PHA, CTLA-4 levels were strongly increased on T cells from controls but in T cells from Wegener's granulomatosis patients this response was severely impaired. Interestingly, while CTLA-4 was seen exclusively on T cells in control individuals, about half of the Wegener's patients showed CTLA-4 expression by a fraction of peripheral B lymphocytes. CTLA-4 positive B cells in the periphery were associated with less acute disease.

CD28 negative T cells are enriched in granulomatous lesions of the respiratory tract in Wegener's granulomatosis

BACKGROUND

Lack of CD28 expression on peripheral blood CD4+ and CD8+ T cells has been reported in patients with Wegener's granulomatosis (WG), suggesting a pathogenetic role of CD28- T cells in WG.

METHODS

Ten patients with WG and six with sarcoidosis (disease control) were analysed. Fluorescence activated cell sorter (FACS) analysis was used to detect CD28 expression on T cells from peripheral venous blood and from bronchoalveolar lavage (BAL) fluid. T cells in biopsy specimens from granulomatous lesions of the upper respiratory tract were analysed for CD28 expression by double immunofluorescence staining.

RESULTS

A significantly higher fraction of CD28- T cells was found in the CD4+ and CD8+ T cell compartment in BAL fluid (65.6 (5.4)% and 76.3 (4.1)%, respectively) than in blood (13.4 (6.2)% and 42.9 (6.2)%; p<0.001) in patients with WG but not in those with acute sarcoidosis (6.7 (2.2)% and 53.4 (7.3)% in BAL fluid v 4.1 (2.5)% and 52.0 (9.4)% in blood). The total number of CD4+/CD28- T cells but not of CD8+/CD28- T cells was also significantly higher in BAL fluid than in blood in patients with WG (p<0.05). Patients with WG had a significantly higher fraction of CD28- T cells in the CD4+ and CD8+ T cell compartment in BAL fluid than patients with acute sarcoidosis (65.6 (5.4)% v 6.7 (2.2)%; p<0.001; and 76.3 (4.1)% v 53.4 (7.3)%; p<0.05). The total number of CD4+/CD28- and CD8+/CD28- T cells was also significantly higher in patients with WG than in those with sarcoidosis (p<0.01). An abundance of CD28- T cells was found in granulomatous lesions by double immunofluorescence staining in patients with WG.

CONCLUSIONS

Our data indicate enrichment of CD28- T cells in BAL fluid and suggest recruitment of CD28- T cells into granulomatous lesions in WG. Further analysis of the phenotype and function of T cell subsets in WG is needed to better understand leucocyte homing in WG and to find new therapeutic targets.

Amphipathic variable region heavy chain peptides derived from monoclonal human Wegener's anti-PR3 antibodies stimulate lymphocytes from patients with Wegener's granulomatosis and microscopic polyangiitis

Amphipathic variable-region heavy chain 11-mer peptides from monoclonal human IgM antiproteinase-3 antibodies were studied for peripheral blood lymphocyte stimulation in 21 patients with Wegener's granulomatosis (WG) or microscopic polyangiitis (MPA), connective tissue disease controls and normal control subjects. Positive T-cell activation was observed in most experiments with WG patients' lymphocytes using amphipathic VH-region peptides from four different human monoclonal anti-PR3 antibodies. Control peptides of the same length but without amphipathic characteristics along with other amphipathic peptides not derived from monoclonal anti-PR3 sequence were employed as controls. No significant lymphocyte stimulation was observed with normal controls, but positive stimulation with amphipathic VH peptides was also recorded in other connective tissue disease controls mainly patients with rheumatoid arthritis. Amphipathic peptides not derived from anti-PR3 sequence did not stimulate WG lymphocytes. Our findings indicate that lymphocyte reactivity as an element of cell-mediated immunity may be activated by amphipathic VH-region amino acid sequences of autoantibodies which are themselves associated with diseases such as WG.

Immunological and clinical follow up of hepatitis C virus associated cryoglobulinaemic vasculitis

OBJECTIVE

To study immunological markers and compare these markers with standard measures for the clinical and immunological follow up of vasculitis activity in hepatitis C virus (HCV) associated cryoglobulinaemic vasculitis (CV).

METHODS

Serial serum samples from eight patients with newly diagnosed HCV associated CV were followed during interferon alpha treatment induced remission of the CV. Vasculitis activity and disease extent were evaluated with the Birmingham vasculitis activity score (BVAS) and disease extent index (DEI). Cryoglobulinaemia, complement levels (C3c, C4, and CH50), rheumatoid factor (RF), autoantibodies such as antinuclear antibodies, soluble interleukin 2 receptor (sIL2r), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble CD30 (sCD30) were determined.

RESULTS

All patients achieved either complete or partial remission of their CV during interferon alpha treatment. There was a significant reduction in vasculitis activity and disease extent (BVAS, DEI), cryoglobulinaemia, RF, sIL2r, sICAM-1, and sCD30. Complement C3c levels increased significantly during this period. Erythrocyte sedimentation rate and levels of complement C4 and CH50 did not change significantly. Both clinical measures (BVAS and DEI) correlated significantly only with C3c and sCD30.

CONCLUSIONS

Although this study was of only a small group of patients, it shows that BVAS and DEI as clinical measures and C3c and sCD30 as immunological markers may be useful in the follow up of disease activity of HCV associated CV. The data indicate that activity of the humoral (cryoglobulinaemia, RF, autoantibodies) and cellular (sIL2r, sICAM-1, sCD30) immune response and endothelial damage (sICAM-1) are found in HCV associated CV.

BPI-ANCA is found in reactive arthritis caused by Yersinia and Salmonella infection and recognise exclusively the C-terminal part of the BPI molecule

OBJECTIVE

To examine the prevalence, binding sites and functional interactions of antineutrophil cytoplasmic autoantibodies (ANCA) against the bactericidal/permeability increasing protein (BPI) in reactive arthritis (ReA).

METHODS

Sera were analysed for the occurrence of ANCA by indirect immunofluorescence microscopy (IIF) and ELISA. Binding sites were determined using BPI, lipopolysaccharid binding protein (LBP), and fusion proteins of both proteins in ELISA. In addition, the effect of antibodies on the antibiotic activity of BPI was examined.

RESULTS

BPI-ANCA was found in patients with Yersinia- and Salmonella-triggered ReA and directed against the C-terminal portion of BPI. Goat anti BPI antibodies recognising this part inhibited the antibiotic activity of BPI in vitro.

CONCLUSION

BPI-ANCA was associated with ReA triggered by Salmonella and Yersinia infection. Directed against the C-terminal part of BPI, it can potentially inhibit its antibiotic activity and might be useful to identify patients with infectious bowel disease prone to extraintestinal sequelae.

Elevated interleukin-4 and interleukin-13 production by T cell lines from patients with Churg-Strauss syndrome

OBJECTIVE

To investigate cytokine production patterns of T cell lines (TCL) from patients with Churg-Strauss syndrome (CSS).

METHODS

Short-term polyclonal TCL were generated from peripheral blood of patients with CSS or Wegener's granulomatosis (WG) and healthy controls (HC). TCL were established in the presence of interleukin-2 (IL-2) and phytohemagglutinin and were phenotypically characterized by flow cytometry. Th1/ Th2 cytokine production by stimulated TCL (72 hours) was analyzed by enzyme-linked immunosorbent assay.

RESULTS

TCL that represented the progeny of in vivo-activated T cells from CSS patients displayed a heterogeneous immunophenotype, with a predominance of CD4+ T cells when compared with WG TCL, which were predominantly CD8+. All CSS TCL shared the ability to produce large amounts of interferon-gamma (IFNgamma), IL-4, and IL-13 compared with HC (P = 0.014 for all 3). Production of IL-4 and IL-13 was higher in CSS TCL than in WG TCL (P = 0.014 for both). IL-5 production was up-regulated in WG TCL compared with CSS TCL (P = 0.014). Compared with HC, WG TCL showed increased production of IFNgamma (P = 0.021), IL-5 (P = 0.043), and IL-13 (P = 0.021).

CONCLUSION

Our results indicate that, while there is evidence for both a type 1 and a type 2 response in CSS, type 2 cytokine production pattern appears to predominate in this disease when compared with WG and HC.

Prevalence and spectrum of rheumatic diseases associated with proteinase 3-antineutrophil cytoplasmic antibodies (ANCA) and myeloperoxidase-ANCA

OBJECTIVES

To evaluate the prevalence and association of antineutrophil cytoplasmic antibodies (ANCA) and their subtypes [proteinase 3 (PR3)-ANCA, myeloperoxidase (MPO)-ANCA] with distinct clinical features in various clinicopathological syndromes.

METHODS

All consecutive ANCA-positive patients seen at the combined unit for rheumatology for Bad Bramstedt and the University of Lübeck between 1989 and 1999 were analysed. ANCA were detected by an immunofluorescence technique and ANCA subspecificities were determined by ELISA. Clinical features at presentation and diagnoses were recorded according to standardized procedures.

RESULTS

Among 4620 patients tested, 333 were cytoplasmic ANCA-positive and 291 were perinuclear ANCA-positive. cANCA/PR3-ANCA were strongly associated with Wegener's granulomatosis (WG), whereas pANCA/MPO-ANCA were associated with a diverse disease spectrum. Further investigation of PR3-ANCA-positive (n=80) and MPO-ANCA-positive patients (n=40) revealed a greater extent of disease [disease extent index (DEI); median 8 vs 5, P<0.01] and more frequent involvement of the upper/lower respiratory tract and the eyes in PR3-ANCA-positive than in MPO-ANCA-positive patients. Fewer than 5% of WG patients were MPO-ANCA-positive. Compared with matched PR3-ANCA-positive WG patients, the MPO-ANCA-positive WG patients had a lower DEI (median 5 vs 8) and had a lower frequency of peripheral neuropathy.

CONCLUSIONS

ANCA testing is useful due to its high sensitivity and specificity, especially for cANCA/PR3-ANCA in WG. We found a divergence in the disease spectrum between PR3- and MPO-ANCA-positive patients, characterized by higher DEI and extrarenal manifestations in the PR3-ANCA group. MPO-ANCA was rarely found in WG and was associated with less organ involvement.

Subthreshold concentrations of anti-proteinase 3 antibodies (c-ANCA) specifically prime human neutrophils for fMLP-induced leukotriene synthesis and chemotaxis

Anti-neutrophil cytoplasmic antibodies (ANCA) targeting proteinase 3 (PR3) possess a high sensitivity and specificity for Wegener's granulomatosis. Due to their capacity of directly activating neutrophils, a pathogenetic role for these autoantibodies has been proposed. We investigated the impact of subthreshold concentrations of monoclonal anti-PR3 antibodies (anti-PR3; 0.1 microg/mL) on neutrophil activation elicited by a secondary agent. Preincubation with anti-PR3 resulted in a massive amplification of N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced leukotriene (LT) generation, with a marked increase in the liberation of LTB4, LTA4, and 5-hydroxyeicosatetraenoic acid (5-HETE). This priming commenced within 2.5 min, with a maximum after 5-7.5 min. Moreover, anti-PR3 pretreatment markedly enhanced PMN movement toward fMLP. The priming effect of anti-PR3 toward fMLP challenge was reproduced by c-ANCA, but not by F(ab)2 fragments of the antibodies and isotype-matched control IgG. Generation of superoxide anion and release of elastase were suppressed in anti-PR3-pretreated neutrophils undergoing fMLP challenge. In contrast, neutrophil activation by platelet-activating factor (PAF) or the calcium ionophore A23187 remained unaffected. We conclude that subthreshold concentrations of anti-PR3 antibodies selectively modify neutrophil responses to fMLP, with enhancement of leukotriene generation and chemotaxis, but suppression of respiratory burst and degranulation. Such priming might contribute to localized neutrophil accumulation together with blunted host defense in Wegener's granulomatosis.

Opsonization of apoptotic neutrophils by anti-neutrophil cytoplasmic antibodies (ANCA) leads to enhanced uptake by macrophages and increased release of tumour necrosis factor-alpha (TNF-alpha)

Since proteinase 3 (PR3)-ANCA interact with PR3 on the surface of apoptotic polymorphonuclear neutrophils (PMN) and ingestion of apoptotic PMN is known to modulate macrophage inflammatory reactions, we raised the question whether PR3-ANCA-opsonized apoptotic PMN influence the uptake by macrophages and their state of activation. We therefore analysed the effects of PR3-ANCA-opsonized apoptotic PMN on the uptake process by enzymatic assay. We further investigated the production of TNF-alpha, IL-10, IL-12 and the secretion of lipid inflammatory mediators (TxB2, leukotriene B4 (LTB4) and prostaglandin E2 (PGE2)) by human monocyte-derived macrophages using FACS and ELISA methods. We show that PMN-opsonization by PR3-ANCA substantially enhances phagocytosis by macrophages and thereby triggers the production of TNF-alpha and TxB2. These in vitro findings indicate that PR3-ANCA opsonization of apoptotic PMN might be an important mechanism in the pathogenesis of Wegener's granulomatosis (WG), prompting macrophages to produce proinflammatory mediators. These mediators, mainly TNF-alpha, might prime further PMN leading to perpetuation of the known priming-dependent mechanisms of ANCA action.

Primary vasculitides and vasculitis confined to skin: clinical features and new pathogenic aspects

Cutaneous vasculitis is a heterogeneous group of disorders, and may occur with virtually all syndromes of vasculitis. It can occur as an isolated dermatologic disorder or as a manifestation of a potentially life-threatening systemic vasculitis. Cutaneous manifestations vary depending on the underlying cause, the size of the vessel involved and the severity and type of inflammation. In this short review, the classification, the characteristic skin manifestations of the primary vasculitides and new pathogenic aspects are discussed.

Localized Wegener's granulomatosis: predominance of CD26 and IFN-gamma expression

The immune response in Wegener's granulomatosis (WG) has been characterized as a predominant, potentially pathogenic Th1-like reaction by blood T cells and T-cell clones from diseased tissues. To elucidate further the immunopathogenic mechanisms, this study analysed the phenotypes of inflammatory infiltrates in frozen nasal biopsies with involvement of the upper respiratory tract only (localized or 'initial phase' WG) and with multi-organ involvement, including systemic vasculitis (generalized WG). The expression and production of Th1 and Th2 cytokines were examined in tissue specimens and peripheral blood mononuclear cells (PBMCs) of localized and generalized WG. The number of CD3+ T cells in inflammatory infiltrates ranged from 50 to 70%, together with approximately 30% CD14+ monocytes/macrophages. An average of 40% of T cells expressed CD26 in nasal biopsies of localized WG, compared with about 16% in specimens of generalized WG. In parallel, a higher number of interferon-gamma (IFN-gamma)-positive cells were detected in nasal tissue of localized than in generalized WG. PBMCs from localized WG similarly exhibited higher spontaneous IFN-gamma production in contrast to generalized WG (207 vs. 3 pg/ml, p<0.05). Interleukin-4 (IL-4) mRNA was found in higher amounts in generalized than in localized WG. IL-4 production was negligible in both disease and controls. In addition, both IL-10 mRNA and IL-10 protein levels of activated PBMCs from localized WG were elevated when compared with generalized disease (574 vs. 154 pg/ml, p<0.05) or healthy controls (574 vs. 246 pg/ml, p<0.05). It is conluded that in nasal tissues, mainly CD4+/CD26+ T cells as well as IFN-gamma-positive cells may support a polarized Th1-like immune response. Furthermore, the data suggest that this in situ immune response is already initiated and established in localized WG, accompanied by increased peripheral IFN-gamma and IL-10 production.

Circulating cytokines and soluble CD23, CD26 and CD30 in ANCA-associated vasculitides

OBJECTIVE

To assess circulating immunoregulatory cytokines and soluble surface markers of T and B cell activation in the plasma of patients with Wegener's granulomatosis (WG), Churg-Strauss syndrome (CSS) and microscopic polyangiitis (MPA) during active and inactive disease, in order to establish their value in discriminating between disease entities and as markers of disease activity.

METHODS

Plasma levels of IL-4, IL-5, IL-10, IL-12, IL-13, IFN-gamma and soluble CD23, CD26 and CD30 were determined by enzyme-linked immunosorbent assay in patients with WG (n = 21), CSS (n = 19) and MPA (n = 14) during active disease and remission.

RESULTS

Concerning cytokines, no differences were observed for IFN-gamma, IL-4, IL-5 and IL-13. Plasma levels of IL-12 were decreased in all subgroups of patients. On the contrary, IL-10 levels were significantly elevated only in patients with CSS. Levels of sCD30 were significantly increased in patients with active generalized WG and CSS, but not in those with MPA and localized WG, correlating with the disease extent and activity. sCD26 levels were markedly decreased in patients with generalized WG, CSS and MPA and increased towards remission. sCD23 levels were slightly, but not significantly increased in CSS and generalized WG.

CONCLUSION

Regarding the investigated immunoregulatory cytokines (Th1/Th2 type), only the measurement of plasma levels of IL-10 discriminated CSS from WG and MPA. The reported data could indicate a similar status of T cell activation in generalized WG and CSS, and possibly a shift in peripheral immunity towards a more humoral dominated immune response. The differences observed between patients with the localized and generalized forms of WG seem to reflect the clinically known biphasic course of this disease.

Anti-neutrophil cytoplasmic antibodies directed against the bactericidal/permeability-increasing protein (BPI) in pediatric cystic fibrosis patients do not recognize N-terminal regions important for the anti-microbial and lipopolysaccharide-binding activity of BPI

This study was performed to examine the prevalence and clinical correlates of bactericidal/permeability-increasing protein anti-neutrophil cytoplasmic antibodies (BPI-ANCA) in pediatric cystic fibrosis (CF) patients and to elucidate their possible role in CF pulmonary pathology. Sera of 27 CF patients were tested for ANCA by indirect immunofluorescence (IFT) and by enzyme-linked immunosorbent assay (ELISA) for ANCA sub-specificities. BPI-ANCA were examined by using standard ELISA for BPI, lipopolysaccharide-binding protein (LBP), and BPI/LBP fusion proteins to epitope map the main binding sites and look for cross-reactivity with LBP. Pulmonary function and serum concentrations of total immunoglobulin G (IgG) were measured and infections were diagnosed. In addition, release of reactive oxygen species (ROS) by neutrophil granulocytes was measured after stimulation with monoclonal BPI-ANCA. Using IFT, two patients showed atypical ANCA staining, six patients exhibited perinuclear ANCA staining, and no cytoplasmic ANCA staining was detected. Of 27 patients, 13 (48%) were BPI-ANCA (IgG) positive, and three were also immunoglobulin A (IgA) BPI-ANCA positive; one patient had ANCA against lactoferrin; and no proteinase 3 ANCA was detected in any of the patients. All BPI-ANCA bound to the C-terminal region of the molecule; none bound to the N-terminus or to LBP. There was no significant correlation between clinical data and the occurrence of BPI-ANCA in this cross-sectional study. Release of ROS from granulocytes was induced by monoclonal BPI-ANCA. Activation of neutrophils and possible modulation of BPI-mediated opsonophagocytosis and disposal of Gram-negative bacteria and lipopolysaccharides by BPI-ANCA raise the possibility that they contribute to pulmonary pathology in pediatric CF patients but intervention longitudinal studies in large groups of patients are needed to establish a causative association.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) but not granulocyte colony-stimulating factor (G-CSF) induces plasma membrane expression of proteinase 3 (PR3) on neutrophils in vitro

The theoretical risk of triggering vasculitis resulting from administration of G-CSF and GM-CSF to patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV), such as Wegener's granulomatosis (WG), who develop agranulocytosis due to cytotoxic therapy, is unknown. Since there is strong evidence that activation of polymorphonuclear neutrophils (PMN) induced by binding of ANCA to PR3 or myeloperoxidase (MPO) expressed on their plasma membrane is involved in the pathogenesis of systemic vasculitides (SV), we studied the surface expression of PR3 and MPO on PMN from healthy donors in response to G-CSF and GM-CSF in vitro by flow cytometric analysis. Increasing doses of G-CSF did not alter PR3 expression on either untreated or tumour necrosis factor-alpha (TNF-alpha)-primed donor PMN significantly. In contrast, GM-CSF significantly increased PR3 membrane expression on both intact PMN and neutrophils primed with TNF-alpha. MPO expression was not significantly altered by either G-CSF or GM-CSF. In summary, these data demonstrate that GM-CSF, but not G-CSF, induces plasma membrane expression of PR3 on PMN in vitro. Since in AAV accessibility of the antigen (PR3 or MPO) to the antibody (ANCA) on the plasma membrane of PMN is thought to be essential for neutrophil activation by ANCA, the results of the present study suggest that administration of GM-CSF to patients with WG with neutropenia implies a definite theoretical risk of deterioration of vasculitis via this mechanism.

Neutrophils synthesize and activate TGFbeta2

Human polymorphonuclear neutrophils (PMN) are regulated by soluble factors such as chemotactic peptides and cytokines. PMN themselves are capable of synthesizing and releasing various cytokines, thereby taking part in the afferent or inductive limb of the immune response. We report for the first time that TGFbeta2 can be synthesized and released by PMN obtained from peripheral blood. Reverse transcriptase polymerase chain reaction (RT-PCR) showed that preparations of PMN express mRNA for transforming growth factor (TGF)beta1 and TGFbeta2 but not for TGFbeta3. Only translation of TGFbeta2 into protein was observed applying different assays. Interestingly, TGFbeta2 in supernatants from stimulated PMN could be detected in the bioactive form.

Activation of neutrophils, eosinophils, and lymphocytes in the lower respiratory tract in Wegener's granulomatosis

Levels of cell products released by neutrophils, eosinophils and lymphocytes were measured in the bronchoalveolar lavage fluid (BALF) of 19 patients with pulmonary active Wegener's granulomatosis (WG) to assess in vivo the magnitude of cellular activation at sites of active disease. Measurements included the BAL cell profile and BALF levels of myeloperoxidase (MPO), free proteinase 3 (fPR3), complexes of PR3 and alpha1-antitrypsin (PR3/alpha1-AT), eosinophil cationic protein (ECP), peroxidase activity (PEROX), and soluble interleukin-2 receptor (sIL-2R). Six patients also underwent a repeat examination after immunosuppressive treatment. Pulmonary active WG was found to be associated with elevated MPO, PEROX, ECP, and sIL-2R levels in BALF. Only trace amounts of fPR3 were detected, the bulk of PR3 being found in PR3/alpha1-AT complexes. Clinically effective treatment depressed BAL neutrophil counts and reversed elevated levels of MPO and PEROX but had an inconsistent effect on the BAL lymphocyte count and the sIL-2R level. In conclusion, the elevated levels of extracellular MPO and PEROX at a site of active disease and the correlation between these and clinical disease activity support the view that neutrophils are indeed an important effector cell population in WG lung disease. The present data also suggest that oxidative injury is an important aspect of neutrophil-mediated lung injury, whereas it remains unresolved whether the low levels of fPR3 in the BALF adequately reflect the situation at inflammatory tissue sites.