A Dutch consensus statement on the diagnosis and treatment of ANCA-associated vasculitis

INTRODUCTION

Despite the availability of several guidelines on the diagnosis and treatment of antineutrophil cytoplasmic antibody-associated vasculitis (AAV), clinical routine practice will only improve when an implementation strategy is in place to support clinical decision making and adequate implementation of guidelines. We describe here an initiative to establish national and multidisciplinary consensus on broad aspects of the diagnosis and treatment of AAV relevant to daily clinical practice in the Netherlands.

METHODS

A multidisciplinary working group of physicians in the Netherlands with expertise on AAV addressed the broad spectrum of diagnosis, terminology, and immunosuppressive and non-immunosuppressive treatment, including an algorithm for AAV patients. Based on recommendations from (inter)national guidelines, national consensus was established using a Delphi-based method during a conference in conjunction with a nationally distributed online consensus survey. Cut-off for consensus was 70% (dis)agreement.

RESULTS

Ninety-eight professionals were involved in the Delphi procedure to assess consensus on 50 statements regarding diagnosis, treatment, and organisation of care for AAV patients. Consensus was achieved for 37/50 statements (74%) in different domains of diagnosis and treatment of AAV including consensus on the treatment algorithm for AAV.

CONCLUSION

We present a national, multidisciplinary consensus on a diagnostic strategy and treatment algorithm for AAV patients as part of the implementation of (inter)national guideline-derived recommendations in the Netherlands. Future studies will focus on evaluating local implementation of treatment protocols for AAV, and assessments of current and future clinical practice variation in the care for AAV patients in the Netherlands.

The avidity of PR3-ANCA in patients with granulomatosis with polyangiitis during follow-up

The objective of this study is to investigate whether the avidity of proteinase-3-anti-neutrophil cytoplasmic antibody (PR3-ANCA) changes during follow-up in different subgroups of patients with granulomatosis with polyangiitis (GPA). We selected 10 patients with renal relapsing GPA, 10 patients with renal non-relapsing GPA and 10 patients with non-renal relapsing GPA. In all patients, an ANCA rise occurred during remission. The avidity was measured using a chaotropic approach at the time of an ANCA rise and at the time of a relapse in relapsing patients or time-matched during remission in non-relapsing patients. No difference was observed in the avidity at the ANCA rise between renal relapsing patients [26·2% (15·5-47·5)], renal patients without a relapse [39·6% (21·2-63·4)] and non-renal relapsing patients [34·2% (21·6-59·5)]. In renal relapsing patients, the avidity increased significantly from the moment of the ANCA rise to the relapse [difference 6·4% (0·0-17·1), P = 0·0273]. The avidity did not increase after an ANCA rise in renal non-relapsing patients [difference 3·5 (-6·0 to 10·1), P = 0·6250] or in non-renal relapsing patients [difference -3·1% (-8·0 to 5·0), P = 0·5703]. The avidity of PR3-ANCA increases after an ANCA rise during follow-up in renal relapsing patients, but not after an ANCA rise in renal patients who remain in remission or in non-renal relapsing patients.

Immunoglobulin G anti-endothelial cell antibodies: inducers of endothelial cell apoptosis in pulmonary arterial hypertension?

Endothelial cell (EC) apoptosis seems to play an important role in the pathophysiology of pulmonary arterial hypertension (PAH). We aimed to test the hypothesis that circulating anti-endothelial cell antibodies (AECA) of PAH patients induce EC apoptosis. Immunoglobulin (Ig)G was purified from sera of PAH patients (n = 26), patients with systemic lupus erythematosus (SLE) nephritis without PAH (n = 16), patients with systemic sclerosis (SSc) without PAH (n = 58) and healthy controls (n = 14). Human umbilical vein endothelial cells (HUVECs) were incubated with patient or healthy control IgG for 24 h. Thereafter, apoptosis was quantified by annexin A5 binding and hypoploid cell enumeration by flow cytometry. Furthermore, real-time cell electronic sensing (RT-CES™) technology was used to monitor the effects of purified IgG from patient and healthy control IgG on HUVECs. As demonstrated previously, IgG of AECA-positive SLE nephritis patients (n = 7) induced a higher percentage of apoptosis of HUVECs compared to IgG of AECA-negative SLE nephritis patients and healthy controls. Furthermore, IgG of AECA-positive SLE nephritis patients induced a marked decrease in cell index as assessed by RT-CES™ technology. IgG of AECA-positive PAH patients (n = 12) and SSc patients (n = 13) did not alter the percentage of HUVEC apoptosis or cell index compared to IgG of AECA-negative PAH and SSc patients and healthy controls. AECA-positive PAH patients, in contrast to SLE nephritis patients, do not have circulating IgG AECA that enhances apoptosis of HUVECs in vitro. Further studies should focus on other mechanisms by which AECA may enhance EC apoptosis in PAH, such as antibody-dependent cell-mediated cytotoxicity.

Serum I-FABP as marker for enterocyte damage in coeliac disease and its relation to villous atrophy and circulating autoantibodies

BACKGROUND

Enterocyte damage is the hallmark of coeliac disease (CD) resulting in malabsorption. Little is known about the recovery of enterocyte damage and its clinical consequences. Serum intestinal fatty acid binding protein (I-FABP) is a sensitive marker to study enterocyte damage.

AIMS

To evaluate the severity of enterocyte damage in adult-onset CD and its course upon a gluten-free diet (GFD). Furthermore, the correlation among enterocyte damage, CD autoantibodies and histological abnormalities during the course of disease is studied.

METHODS

Serum I-FABP levels were determined in 96 biopsy-proven adult CD patients and in 69 patients repeatedly upon a GFD. A total of 141 individuals with normal antitissue transglutaminase antibody (IgA-tTG) levels served as controls. I-FABP levels were related to the degree of villous atrophy (Marsh grade) and IgA-tTG.

RESULTS

I-FABP levels were elevated in untreated CD (median 691 pg/mL) compared with controls (median 178 pg/mL, P < 0.001) and correlated with Marsh grade (r = 0.265, P < 0.05) and IgA-tTG (r = 0.403, P < 0.01). Upon a GFD serum levels decreased significantly, however, not within the range observed in controls, despite the common observed normalisation of IgA-tTG levels and Marsh grade. CD patients with elevated I-FABP levels nonresponding to GFD showed persistent histological abnormalities.

CONCLUSIONS

Enterocyte damage assessed by serum I-FABP correlates with the severity of villous atrophy in coeliac disease at the time of diagnosis. Although enterocyte damage improves upon treatment, substantial enterocyte damage persists despite absence of villous atrophy and low IgA-tTG levels in the majority of cases. Elevated I-FABP levels nonresponding to gluten-free diet are indicative of histological abnormalities and warrant further evaluation.

Increased cytokines, chemokines and soluble adhesion molecules in exhaled breath condensate of asthmatic children

BACKGROUND

Airway inflammation in asthma is characterized by the production of cytokines, chemokines and soluble adhesion molecules. The assessment of these inflammatory biomarkers in exhaled breath condensate (EBC) is hampered by low detection rates. However, the use of a glass condenser system combined with a sensitive analytical technique may increase the possibility to assess these biomarkers in EBC in a reliable way.

OBJECTIVE

(1) To assess the detection rates of cytokines (IL-1alpha, -1beta, -2, -4, -5, -6, -10, -12p70, -13, -18, IFN-gamma, TNF-alpha), chemokines [MIP1alpha (CCL3), MIF, eotaxin (CCL11), RANTES (CCL5), IP10 (CXCL10), IL8 (CXCL8), MCP1] and soluble adhesion molecules [soluble intercellular adhesion molecule (sICAM), soluble vascular adhesion molecule (sVCAM)] in EBC of children with asthma and healthy control children; (2) To study the differences in the biomarker concentration between children with asthma and controls.

METHODS

Sixty children were included: 31 asthmatics (71% atopic) and 29 controls. Exhaled breath condensate was collected using a glass condenser system. The inflammatory markers (IM) were analysed using multiplex immunoassay technology.

RESULTS

Detection percentages of cytokines, chemokines and adhesion molecules ranged from 94% to 100%, except for eotaxin (CCL11) and RANTES (CCL5) (detection rates of 10% and 45% in healthy controls, respectively). The intra-subject variability of biomarkers in EBC in the group as a whole ranged from 5.2% to 35.0%. In asthmatics, the levels of cytokines (IL-2, -4, -5, -6, -13, IFN-gamma), chemokines (MIP1alpha [CCL3], MIF, RANTES [CCL5], IP10 [CXCL10], IL8 [CXCL8], MCP1) and adhesion molecules (sICAM, sVCAM) were significantly increased in comparison with controls (P<0.05).

CONCLUSION

If collected with a glass condenser and analysed by multiplex immunoassay technology, cytokines, chemokines and soluble adhesion molecules can be reliably demonstrated in EBC of children. Most of these IM were elevated in EBC of asthmatics compared with controls.

Haptoglobin phenotype may alter endothelial progenitor cell cluster formation in cerebral small vessel disease

Cerebral small vessel disease results in silent ischemic lesions (SIL) among which is leukoaraiosis. In this process, endothelial damage is probably involved. Endothelial progenitor cells (EPC), are involved in endothelial repair. By restoring the damaged endothelium, EPC could mitigate SIL and cerebral small vessel disease. Haptoglobin 1-1, one of three phenotypes of haptoglobin, relates to SIL and may therefore attenuate the endothelial repair by EPC. Our aim was to quantify EPC number and function and to assess haptoglobin phenotype and its effect on EPC function in patients with a high prevalence of SIL: lacunar stroke patients. We assessed EPC In 42 lacunar stroke patients and 18 controls by flow cytometry and culture with fetal calf serum, patient and control serum. We determined haptoglobin phenotype and cultured EPC with the three different haptoglobin phenotypes. We found that EPC cluster counts were lower in patients (96.9 clusters/well +/- 83.4 (mean +/- SD)), especially in those with SIL (85.0 +/- 64.3), than in controls (174.4 +/- 112.2). Cluster formation was inhibited by patient serum, especially by SIL patient serum, but not by control serum. Patients with haptoglobin 1-1 had less clusters in culture, and when haptoglobin 1-1 was added to EPC cultures, cluster numbers were lower than with the other haptoglobin phenotypes. We conclude that lacunar stroke patients, especially those with SIL, have impaired EPC cluster formation, which may point at decreased endothelial repair potential. The haptoglobin 1-1 phenotype is likely a causative factor in this impairment.

Anti-oxLDL antibody isotype levels, as potential markers for progressive atherosclerosis in APOE and APOECD40L mice

In humans and animal models of atherosclerosis, antibodies against oxidized LDL have been associated with atherosclerotic lesion development. It has been suggested that IgM anti-oxLDL antibodies are anti-atherogenic, whereas IgG anti-oxLDL antibodies are pro-atherogenic. In this study, we examined the relation between IgM and IgG antibody levels and atherosclerosis severity in APOE(-/-)CD40L(-/-) mice, which are deficient for IgG and develop moderate advanced atherosclerosis, and compared results with mice developing severe (APOE(-/-)) or no atherosclerosis (C57Bl/6). Mice were followed in time for anti-oxLDL antibodies while on high-fat diet or normal chow. Anti-oxLDL antibody levels were determined by ELISA. Results revealed that 24-week-old APOE(-/-)CD40L(-/-) mice had enhanced IgM anti-oxLDL antibody levels when compared with wild-type mice, but similar levels to those of APOE(-/-) mice. As expected, IgG anti-oxLDL antibody levels were almost absent in APOE(-/-)CD40L(-/-) mice. The transition from early to advanced lesions in APOE(-/-) mice was reflected by elevated IgM anti-oxLDL antibody levels. IgM anti-oxLDL levels did not further increase during progression to more advanced lesions. No relation was found between IgG anti-oxLDL levels and atherosclerosis severity. In conclusion, the severity of advanced atherosclerosis in mice is not reflected by IgM and/or IgG anti-oxLDL antibody levels. Furthermore, less advanced atherosclerotic lesion development in APOE(-/-)CD40L(-/-) mice does not seem to be the result of higher levels of protective IgM anti-oxLDL antibodies. Therefore, our study does not support the idea that the previously observed inconsistency in the relation between anti-oxLDL and atherosclerosis severity is due to differences in antibody isotypes.

Exhaled nitric oxide and biomarkers in exhaled breath condensate indicate the presence, severity and control of childhood asthma

BACKGROUND

Exhaled nitric oxide and inflammatory biomarkers in exhaled breath condensate may be useful to diagnose and monitor childhood asthma. Their ability to indicate an asthma diagnosis, and to assess asthma severity and control, is largely unknown.

OBJECTIVE

To study (1) the ability of exhaled nitric oxide and inflammatory markers in exhaled breath condensate (nitrite, nitrate, hydrogen peroxide, 8-isoprostane, IFN-gamma, TNF-alpha, IL-2, -4, -5, -10 and acidity) to discriminate between childhood asthma and controls. (2) The ability of these biomarkers to indicate asthma severity and control.

METHODS

One-hundred and fourteen children were included: 64 asthmatics (10.7+/-3.0 years, 67.2% atopic) and 50 controls (10.0+/-0.4 years). Condensate was collected using a glass condenser.

RESULTS

Exhaled nitric oxide, IFN-gamma and IL-4 in exhaled breath condensate differed significantly between asthma and controls. Multivariate backward logistic regression models demonstrated that IL-4 (odds ratio 7.9, 95% confidence interval 1.2-51.0) was the only significant indicator of an asthma diagnosis. Asthma control was best assessed by exhaled nitric oxide, 8-isoprostane, IFN-gamma and IL-4 (sensitivity 82%, specificity 80%, P<0.05), whereas exhaled nitric oxide, 8-isoprostane, nitrate and nitrite in condensate were the best indicators of asthma severity (sensitivity 89%, specificity 72%, P<0.05).

CONCLUSION

Different markers in condensate are of an additional value to exhaled nitric oxide, and are needed in non-invasive inflammometry. They could be useful to diagnose asthma and to indicate asthma control and severity in childhood.

Anti-oxidized low-density lipoprotein antibodies in myeloperoxidase-positive vasculitis patients preferentially recognize hypochlorite-modified low density lipoproteins

Many patients surviving vasculitis are prone to accelerated atherosclerosis and often have enhanced levels of antibodies to oxidized low-density lipoprotein (oxLDL). To measure anti-oxLDL antibodies, oxidation of LDL is achieved with copper (Cu) or malondialdehyde (MDA). Because, in vivo, LDL may be oxidized with myeloperoxidase (MPO) or its product hypochlorite, we measured anti-hypochlorite LDL antibodies in patients with vasculitis, haemodialysis patients and healthy controls. A newly developed enzyme-linked immunosorbent assay (ELISA) was used to detect antibodies to oxLDL as modified by hypochlorite. Results are compared with data obtained by standard LDL oxidation using MDA-LDL or Cu-LDL as substrate. Results were compared between anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) patients (n = 93), haemodialysis (HD) patients (n = 59) and healthy controls (HC; n = 43). Furthermore, patients with MPO-ANCA-associated vasculitis (n = 47) were compared with patients with proteinase 3 (PR3)-ANCA associated vasculitis (n = 46). Optimal cut-off points were determined by receiver operator characteristic (ROC) curve analysis. Anti-oxLDL antibodies are enhanced in AAV patients (MDA-LDL and hypochlorite-LDL) and in HD patients (hypochlorite-LDL), when compared to HC. Furthermore, patients with MPO-ANCA-associated vasculitis had higher levels of antibodies to hypochlorite-LDL than patients with PR3-ANCA-associated vasculitis. Our newly developed assay, in which hypochlorite-LDL is used as substrate, seems a more sensitive assay than traditional assays to measure oxLDL antibodies. Furthermore, our results suggest that enhanced MPO-mediated LDL oxidation occurs in patients with MPO-ANCA.

Cytokines and soluble CD14 in breast milk in relation with atopic manifestations in mother and infant (KOALA Study)

BACKGROUND

Conflicting evidence exists concerning the protective role of breastfeeding in allergy and atopic disease aetiology. Breast milk contains biologically active molecules influencing the innate immune system of newborns.

OBJECTIVE

We aim to assess whether cytokines (TGF-beta1, IL-10 and IL-12) and soluble CD14 (sCD14) in breast milk are influenced by maternal atopic constitution and modify the development of atopic manifestations in infants.

METHODS

Milk samples were collected at 1 month post-partum of 315 lactating mothers participating in the ongoing KOALA Birth Cohort Study. The cytokines and sCD14 were analysed by ELISA in the aqueous fraction. We compared the concentrations of cytokines and sCD14 in breast milk between mothers with and without an allergic history and also with and without allergic sensitization (specific IgE). Associations of cytokines and sCD14 with the development of eczema, wheezing in the first 2 years of life and allergic sensitization of infants at the age of 2 years were analysed by multivariate logistic regression analyses to correct for confounders.

RESULTS

We found higher sCD14 levels in mothers with a positive vs. negative allergic history (7.6 vs. 7.0 microg/mL; P = 0.04) and in mothers who were sensitized vs. non-sensitized (7.8 vs. 7.1 microg/mL; P = 0.03). None of the studied immune factors were associated with infant's atopic outcomes. IL-10 was not detected above the detection limit of 0.2 pg/mL.

CONCLUSION

Taking together the results of the present and previous studies, we conclude that there is no convincing evidence for a relation between TGF-beta1, sCD14, IL-10 or IL-12 in breast milk and atopic manifestations in infants.

Leukocyte CD40L deficiency affects the CD25+ CD4 T cell population but does not affect atherosclerosis

Inhibition of CD40-CD40L interactions results in a reduction of innate regulatory T cells (Tregs) in CD40(-/-) mice and induces a stable plaque phenotype in atherosclerosis-prone mouse strains. Here we investigated the effects of leukocyte CD40L on the Treg population and on atherosclerosis. LDLR(-/-) mice were reconstituted with wild-type or CD40L(-/-) bone marrow (BM). These BM chimeras were analysed by flow cytometry for the presence of innate Tregs (CD45RB(low) CD25(+) CD4) in lymphoid organs and peripheral blood. As in CD40(-/-) mice, the CD45RB(high):CD45RB(low) CD4 T cell ratio significantly increased and the CD25(+) CD4(+) subpopulation significantly decreased in LDLR(-/-) mice receiving CD40L(-/-) BM compared to LDLR(-/-) mice receiving wild-type BM. However, atherosclerotic plaque progression and plaque phenotype did not change in LDLR(-/-) mice reconstituted with CD40L(-/-) BM. In conclusion, the present study shows that CD40-CD40L interactions on leukocytes are essential for the size of the CD45RB(low) CD25(+) CD4 Treg subpopulation. Nevertheless, CD40L deficiency on hemopoietic cells did not affect atherosclerosis, implying that CD40L expressing leukocytes alone are not responsible for the stable plaque phenotype observed after total CD40L blockade.

Evaluation of a new fluorescent-enzyme immuno-assay for diagnosis and follow-up of ANCA-associated vasculitis

In this study we have evaluated a new, fully automated fluorescent-enzyme immuno-assay (FEIA) for detection and quantification of anti-PR3 and anti-MPO ANCA in diagnosis and follow-up of ANCA-associated small vessel vasculitis (AAV). PR3- and MPO-ANCA were determined by FEIA technology in (1) sera of 87 consecutive patients with biopsy-proven, pauci-immune necrotizing crescentic glomerulonephritis (NCGN) and 72 controls; (2) 120 sera (60 patients with Wegener's granulomatosis and 60 controls) that were previously used in a multicentre comparison of direct and capture ELISAs for PR3-ANCA; (3) in samples preceding relapse in 23 PR3-AAV patients with and 23 matched PR3-AAV patients without relapse for prediction of relapses. PR3- and/or MPO-ANCA detection in pauci-immune NCGN by FEIA revealed an overall sensitivity of 82.8%. The FEIA specificity was 96% and 100% for PR3- and MPO-ANCA, respectively. The overall sensitivity of MPO- and PR3-ANCA could be increased to 88.5% by lowering the cut-off values without affecting the specificity (ROC-curve analysis), which is similar to a multistep ANCA procedure that combines indirect immunofluorescence with direct and capture ELISAs. The sensitivity for Wegener's granulomatosis (WG) of the PR3-ANCA FEIA (60%) was more comparable to direct ELISAs (64%) than to capture ELISAs (74%). A rise of 100% in ANCA level as measured by FEIA appeared optimal (ROC-curve) for prediction of relapses and such a rise was observed in 26 patients. In 18 of these 26 patients the rise was followed by a relapse (PPV 69%), whereas in 15 of the 20 patients without a rise no relapse was observed (NPV 75%). In conclusion, detection of PR3- and MPO-ANCA by FEIA has excellent performance in terms of diagnosis of AAV patients. Furthermore, detection of rises in PR3-ANCA by FEIA for prediction of relapses gives results comparable to other techniques.

From ANA to ENA: how to proceed?

Anti-nuclear antibodies (ANA), as detected by indirect immuno-fluorescence, are hallmarks of autoimmune connective tissue diseases. Identification of the specificity for extractable nuclear antigens (ENA) is warranted because this may further differentiate between the distinct types of autoimmune connective tissue diseases. In recent years several different ENA, as recognized by ANA, have been identified and the knowledge of the molecular structure has been expanded. Together with technical developments this has enabled the introduction of several new anti-ENA antibody detection systems. In this review we will discuss the main logistic aspects of anti-ENA antibody testing that have to be solved in order to come to a consensus in order to deal with new developments in this field. We conclude that: 1. a positive ANA test should, depending on the titre and pattern, be followed by an anti-ENA antibody assay, 2: to fully appreciate the value of the new anti-ENA antibody detection systems a large, multicenter clinical evaluation is required, and 3: proper interpretation of reported test results requires that the clinician is aware of the way anti-ENA antibodies are detected and reported.

Cyclosporin-A differentially affects apoptosis during in vivo rat thymocyte maturation

Maturation arrest and interference with selection are two well-documented effects of cyclosporin-A (CsA) on the thymus. We recently hypothesized that these effects are related and owing to the reduced T-cell receptor (TCR)-CD3 complex-mediated signal transduction in thymocytes upon CsA treatment. In this hypothesis, the maturation arrest is the result of the additional depletion of thymocytes that normally survive by positive selection, whereas the impaired self-tolerance induction is caused by an increased survival of thymocytes that normally undergo negative selection. In this view, it is anticipated that CsA differentially affects thymocyte apoptosis during in vivo thymocyte maturation. Indeed, we report in this study a strong increase in apoptotic cells in the thymic cortex on in situ analysis. Simultaneously, the number of apoptotic cells had decreased at the cortico-medullary zone which is held to be the site for negative selection. Rapamycin (Rapa) also interferes with thymocyte maturation by inhibiting cytokine-driven proliferation. Hence, Rapa preferentially affects the early maturational stages of thymocyte development and is considered not to alter thymocyte selection and subsequent apoptotic events. Indeed, the number of apoptotic events appears not to be altered. However, possibly owing to the decrease in cortical macrophages, the apoptotic cells revealed an atypical enumeration around blood vessels. Taken together, our results favour the hypothesis that the dominant effect of CsA on the thymus is the reduction of the TCR-CD3 complex-mediated signal transduction in thymocytes upon interaction with stromal cells. Furthermore, the preferential localization of apoptotic cells next to blood vessels upon Rapa administration may indicate that endothelial cells are a back-up system for the removal of apoptotic cells.