Pathogenesis of PR3-ANCA associated vasculitis

Wegener's Granulomatosis (WG) is closely associated with antineutrophil cytoplasmic autoantibodies (ANCA), particularly those directed to proteinase 3 (PR3). ANCA directed to myeloperoxidase (MPO) are associated with microscopic polyangiitis (MPA) and the Churg Strauss syndrome. PR3-ANCA associated vasculitis differs from MPO-ANCA associated vasculitis particularly in the occurrence of granulomatous inflammation and more widespread disease in the former condition. Studies in experimental animals strongly suggest a pathogenic role for MPO-ANCA, but this is less clear for PR3-ANCA. Here, we review pathogenic pathways in PR3-ANCA associated vasculitis focussing on unique patterns of PR3 expression on the neutrophil membrane in WG, as surface expression of PR3 is a prerequisite for stimulation by PR3-ANCA; (PR3-specific) cellular immunity in WG; and the role of Staphylococcus aureus carriage in this disease. These factors, together, may explain, at least in part, differences in clinical expression between MPO-ANCA and PR3-ANCA associated vasculitis.

Regulation of cytokine-induced HIF-1alpha expression in rheumatoid synovial fibroblasts

The transcription factor hypoxia-inducible factor (HIF)-1 plays a central physiological role in oxygen and energy homeostasis, and is activated during hypoxia by stabilization of the subunit HIF-1alpha. Activation can also occur by proinflammatory cytokines during inflammation. Hypoxia, as well as proinflammatory cytokines, plays an important role in the synovia in rheumatoid arthritis (RA) patients. Expression of HIF-1alpha has been demonstrated in RA synovial lining layer. The aim of the study was to investigate the regulation of the intracellular signal transduction pathways, involved in the expression of HIF-1alpha, and in the expression of genes regulated by HIF-1alpha in rheumatoid synovial fibroblasts (RSF). RSF were cultured under proinflammatory conditions (IL-1beta and TNF-alpha stimulation) and under chemical hypoxia (CoCl2 treatment). Expression of HIF-1alpha was analyzed in nuclear extracts by Western blotting. The effect of inhibitors of the PI3K and the ERK pathway on HIF-1alpha protein expression was measured. mRNA expression of HIF-1alpha, COX-2, vascular endothelial growth factor (VEGF), and stromal cell-derived factor (SDF)-1 was determined by real-time RT-PCR, and protein production of VEGF and SDF-1 by ELISA. Treatment of the synovial fibroblasts with 150 mM CoCl2 as well as stimulation with 10 ng/mL IL-1beta or TNF-alpha resulted in strong protein expression of HIF-1alpha, measured with Western blotting. Pretreatment with the MEK1/2 inhibitor PD98059 as well as the PI3K inhibitor LY294002 resulted in inhibition of the cytokine-induced HIF-1alpha expression. Furthermore, it was shown that cytokine-induced mRNA expression of HIF-1alpha was inhibited by the PI3K inhibitor. We found that cytokine stimulation induced VEGF mRNA and protein production, but no significant effect of kinase inhibition was found on VEGF production in cytokine-stimulated RSF. Both the ERK pathway and the PI3K pathway are involved in the cytokine-induced HIF-1alpha expression in RSF and in the expression of proangiogenic factors.

A 10% ready-to-use intravenous human immunoglobulin offers potential economic advantages over a lyophilized product in the treatment of primary immunodeficiency

Intravenous immunoglobulin (IVIg) replacement therapy is the standard of care for patients with primary humoral immunodeficiencies. This study evaluated differences in infusion time between a 10% IVIg ready-to-use solution and a 6% IVIg lyophilized product and addressed potential cost implications. After receiving in-hospital treatment with 6% IVIg lyophilized solution for at least 6 months, 14 patients with humoral immunodeficiency without anti-IgA antibodies received five successive infusions with 10% IVIg ready-to-use solution. Data on infusion times were collected during the last two infusions of each IVIg product when maximum infusion rates had been reached. The median infusion time was reduced from 104.4 min with the 6% IVIg lyophilized solution to 51.0 min with the 10% IVIg ready-to-use solution (51% reduction), with corresponding median maximum infusion rates of 4.1 ml/kg/h and 5.9 ml/kg/h, respectively. Median gammaglobulin (IgG) trough levels were 7.1 g/l for the 6% IVIg lyophilized solution and 7.9 g/l for the 10% IVIg ready-to-use solution. Fewer adverse events were observed after infusing with 10% IVIg ready-to-use solution compared with 6% IVIg lyophilized preparation. We conclude that the 10% IVIg ready-to-use solution was well tolerated by most patients and reduced the median infusion time by 51% compared with a 6% lyophilized preparation of IVIg. The reduced bed occupancy and nursing time associated with a reduced infusion time, together with the elimination of a reconstitution step, were estimated to provide a cost-saving of 59.42 euros per patient per infusion. Thus, this product has the potential to reduce overall costs of IVIg treatment. Reduced infusion time is also likely to improve patients' quality of life.

Influenza vaccination does not result in an increase in relapses in patients with ANCA-associated vasculitis

BACKGROUND

Vaccination against influenza has been suggested to induce relapses of ANCA-associated vasculitis but evidence is lacking. In this study, we assessed whether vaccination against influenza increases the occurrence of relapses in patients with ANCA-associated vasculitis.

METHODS

Two hundred and thirty consecutive patients with ANCA-associated vasculitis from our out-patient clinics of a tertiary referral center, with at least 1 year of follow-up, were included. Retrospectively, the relapse rate per 100 patients at risk in patients who had been vaccinated against influenza within the preceding year and in patients who not had been vaccinated within that time period were calculated.

RESULTS

The relapse rate per 100 patients at risk was lower in patients who had been vaccinated against influenza (3.4) than in patients who had not been vaccinated (6.3), when analyzed for the entire year and for every quarter of the year. Also, the disease-free survival per separate year according to the vaccination status was lower in all 5 years in patients who had been vaccinated, being statistically significant in 2 years.

CONCLUSION

Vaccination against influenza does not increase the relapse rate in patients with ANCA-associated vasculitis.

Urinary matrix metalloproteinases reflect renal damage in anti-neutrophil cytoplasm autoantibody-associated vasculitis

Renal expression of MMP-2, -9, and tissue inhibitor of MMP-1 (TIMP-1) correlates with histological disease activity in anti-neutrophil cytoplasm autoantibody (ANCA)-associated vasculitis (AAV). We studied whether urinary and plasma levels of MMP-2, -9, and TIMP-1 reflect renal expression of these proteins and renal disease-activity in AAV. Urine and plasma samples of patients with AAV who underwent a renal biopsy were collected (n = 32). Urinary activity of MMP-2 and -9 was measured by activity assays. Urinary and plasma levels of MMP-2, MMP-9, and TIMP-1 proteins were measured by ELISA. Healthy controls provided plasma and urine for comparison (n = 31). In patients, the relationship of urinary and plasma levels with renal expression of MMP-2 and MMP-9 and clinical and histological disease activity was studied. Renal MMP expression was compared between patients and controls (n = 8). Urinary MMP-2 and MMP-9 activity and urinary and plasma TIMP-1 levels were significantly higher in patients than in controls. In glomeruli of patients, both MMP-2 and MMP-9 expression reflected active glomerular inflammation. Urinary activity of MMP-2 and MMP-9 did not correlate with renal MMP expression or plasma levels. Urinary MMP activity correlated negatively with glomerular inflammation, but positively with fibrous crescents. Urinary MMP-2 and TIMP-1 levels showed a positive correlation with tubulointerstitial damage and a negative correlation with creatinine clearance. Urinary MMP-2, MMP-9, and TIMP-1 are elevated in AAV but do not reflect renal MMP expression and glomerular inflammation. However, urinary MMP-2 activity and TIMP-1 levels reflect tubulointerstitial damage and correlate negatively with creatinine clearance at biopsy.

Enhanced endothelium-dependent microvascular responses in patients with Wegener's granulomatosis

OBJECTIVE

To assess endothelial cell (EC) function of the cutaneous microcirculation in patients with Wegener's granulomatosis (WG) and to relate EC function to EC activation and presence of atherosclerosis.

METHODS

We studied 28 WG patients with inactive disease and 28 age and sex matched controls. Common carotid intima-media thickness (IMT), as a measure of atherosclerosis, was determined by ultrasonography. EC function of microcirculation in the fingers was assessed using laser Doppler fluxmetry in combination with iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP), which are endothelium-dependent and endothelium-independent vasodilators, respectively. In addition to vascular responses, traditional cardiovascular risk factors were recorded, and EC activation was assessed by serological measures.

RESULTS

WG patients had increased IMT compared to controls (0.71 mm vs 0.66 mm; p < 0.05). In WG patients IMT correlated positively with age and body mass index (BMI), and negatively with duration of prednisolone use and cumulative prednisolone dose. Levels of von Willebrand factor and C-reactive protein were increased in patients with WG (p < 0.05). ACh-induced but not SNP-induced vasodilatation was enhanced in WG patients compared to controls. When patients and controls with increased IMT were excluded, the difference in relative response to ACh became significant (median 567% vs 334%; p = 0.007). The response to ACh correlated negatively with age.

CONCLUSION

We confirmed that WG patients have accelerated atherosclerosis as measured by IMT. EC activation and disturbed microvascular endothelium-dependent vasodilatation were present in the microcirculation of WG patients with inactive disease and without signs of atherosclerosis, indicating and contributing to a proatherogenic state.

Rats and mice immunised with chimeric human/mouse proteinase 3 produce autoantibodies to mouse Pr3 and rat granulocytes

AIM

In this study, we employed chimeric human/mouse Proteinase 3 (PR3) proteins as tools to induce an autoantibody response to PR3 in rats and mice.

METHOD

Rats and mice were immunised with recombinant human PR3 (HPR3), recombinant murine PR3 (mPR3), single chimeric human/mouse PR3 (HHm, HmH, mHH, mmH, mHm, Hmm) or pools of chimeric proteins. Antibodies to mPR3 and HPR3 were measured by ELISA. Antibodies to rat PR3 were determined by indirect immunofluorescence (IIF) on rat white blood cells. Urinalysis was performed by dipstick analysis. Kidney and lung tissue was obtained for pathological examination.

RESULTS

In mice, immunisation with the chimeric human/mouse PR3 Hmm led to an autoantibody response to mPR3. Rats immunised with the chimeric human/mouse PR3 Hmm, HmH and mmH, or a pool of the chimeric human/mouse PR3 proteins, produced antibodies selectively binding to rat granulocytes as detected by IIF. No gross pathological abnormalities could be detected in kidney or lungs of mice or rats immunised with chimeric human/mouse PR3.

CONCLUSION

Immunisation with chimeric human/mouse proteins induces autoantibodies to PR3 in rats and mice. Chimeric proteins can be instrumental in developing experimental models for autoimmune diseases.

Ultraviolet light and cutaneous lupus

Exposure to ultraviolet (UV) light is one of the major factors known to trigger cutaneous disease activity in (systemic) lupus erythematosus patients. UV light, UVB in particular, is a potent inducer of apoptosis. Currently, disturbed clearance of apoptotic cells is one of the concepts explaining the development of inflammation in lupus patients. We review the role of apoptotic cells and autoantibodies in the pathogenesis of UVB induced skin lesions.

The future of damage assessment in vasculitis

Damage denotes the aspects of chronic disease that do not reverse with therapy. This concept is particularly important for the primary systemic vasculitides, since the careful differentiation between activity and damage may help avoid unnecessary exposure to cytotoxic medications. Damage significantly influences both longterm prognosis and quality of life. Because the primary systemic vasculitides have diverse manifestations, the use of a damage assessment instrument is crucial to ensure reproducibility. The Vasculitis Damage Index (VDI) is the only validated measure for damage assessment in vasculitis. Use of the VDI in recent clinical trials has shown that it may not adequately determine the full spectrum of damage experienced by patients with vasculitis of small- and medium-size vessels. We propose reexamining the way in which damage is assessed, focusing on vasculitides of small- and medium-size vessels, and outline an initiative to create a substantially revised and improved damage assessment instrument using data-driven approaches. This initiative is part of a larger international effort to create a unified approach to disease assessment for the primary systemic vasculitides.

Plasma kynurenine and related measures in tic disorder patients

OBJECTIVE

Increased plasma kynurenine has been reported in tic disorder patients, and this observation has been suggested to be indicative of immune dysregulation. In the present study, we examined plasma levels of kynurenine and related molecules in a group of tic disorder patients.

METHODS

Plasma concentrations of tryptophan, kynurenine, cortisol, and neopterin were determined in Dutch tic disorder patients (N = 59), and healthy volunteers (N = 32). Group means were compared and age-controlled intra-individual correlations between tic severity and plasma levels of these molecules were examined.

RESULTS

No significant differences were found between patient and control groups in plasma levels of tryptophan, kynurenine, and cortisol concentrations, nor in the kynurenine/tryptophan ratio. However, neopterin was significantly (p = 0.035) higher in patients (mean = 5.13 nmol/l) than in controls (mean = 3.30 nmol/l). Plasma levels of these molecules did not correlate with tic severity, with the exception of tryptophan (r = -0.289, p = 0.049). In patients, plasma neopterin correlated with kynurenine (r = 0.438, p = 0.002); in healthy subjects, tryptophan correlated with kynurenine (r = 0.670, p < 0.001).

CONCLUSION

While the observed elevation in plasma neopterin is consistent with immune activation in a subset of tic disorder patients, metabolism of tryptophan through the kynurenine pathway appears to be unaltered in tic disorder patients.

CD4-Positive Effector Memory T Cells Participate in Disease Expression in ANCA-Associated Vasculitis

Although the cause of ANCA-associated vasculitis (AAV) remains undetermined, the presence of lymphocytic infiltrates in inflammatory lesions of patients suggests that vascular damage is immune mediated. Studies over the past decade have implicated a role for T cells in the pathogenesis of AAV as altered T cell phenotype has been observed in this disorder. The distribution of T cell subpopulations has been analyzed most intensely in Wegener's granulomatosis (WG), where an expanded population of circulating CD4(+) effector memory T cells (CD4(+)T(EM)) was demonstrated. CD4(+)T(EM) cells play a major role in the pathogenesis of several autoimmune diseases. Specific suppression of CD4(+)T(EM) cells inhibits delayed-type hypersensitivity (DTH) and has therapeutic potential in autoimmune disease. Thus, CD4(+)T(EM) cells may act as inducers of tissue injury and participate in the development of AAV. Therapies that target CD4(+)T(EM), without impairing the activity of other lymphocyte subsets, may hold therapeutic promise for AAV.

Autoantibodies against Protective Molecules C1q, C-Reactive Protein, Serum Amyloid P, Mannose-Binding Lectin, and Apolipoprotein A1: Prevalence in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of several autoantibodies. Among the multiple factors involved in SLE development, apoptotic defects and impaired clearance of cellular debris have gained considerable interest, as they contribute to autoantigen overload. Several molecules of the innate immunity, also participate in the removal of damaged and apoptotic cells. Among them are C1q, C-reactive protein (CRP), serum amyloid P protein (SAP), mannose-binding lectin (MBL), and apolipoprotein A1 (APO A1). To evaluate the prevalence of autoantibodies against CRP, SAP, MBL, APO A1, and C1q among SLE patients, and their relationship with disease activity, a total of 150 SLE patients were screened for the presence of elevated antibody titers against C1q, CRP, SAP, MBL, and APO A1, utilizing the enzyme-linked immunosorbent assay (ELISA) method. Disease activity was assessed using the ECLAM or SLEDAI scores. The study population comprised two groups of patients: 100 patients with quiescent disease (median ECLAM score 2) comprised the first group, and 50 patients with active disease (median SLEDAI score 16) comprised group 2. Elevated titers of anti-CRP antibodies were significantly elevated only in group 1 (10% versus 4% of controls). Antibodies against SAP were evaluated only among patients in group 1, and were found at a significant high prevalence (20%). Elevated titers of anti-MBL antibodies were significantly elevated only in group 1 (15% versus 3.6%); and antibodies directed against APO A1 were significantly elevated in 21% of group 1, and 50% of group 2 patients. Elevated titers of anti-C1q were evaluated only in group 2, and were found at a significant prevalence of 66%. Significant correlation with disease activity was found only for anti-APO A1 antibodies, and only in group 1. Several patients harbored more than one of the autoantibodies tested. In patients with SLE, autoantibodies directed against protective molecules, that is, acute-phase proteins involved in the disposal of cellular and nuclear debris, can be detected. These autoantibodies may play a pathogenic role in the development or perpetuation of autoimmunity in SLE.

The future of biologic agents in the treatment of Sjögren's syndrome

The gain in knowledge regarding the cellular mechanisms of T and B lymphocyte activity in the pathogenesis of Sjögren's syndrome (SS) and the current availability of various biological agents (anti-TNF-alpha, IFN- alpha, anti-CD20, and anti-CD22) have resulted in new strategies for therapeutic intervention. In SS, various phase I and II studies have been performed to evaluate these new strategies. Currently, B cell-directed therapies seem to be more promising than T cell-related therapies. However, large, randomized, placebo-controlled clinical trials are needed to confirm the promising results of these early studies. When performing these trials, special attention has to be paid to prevent the occasional occurrence of the severe side effects.

Prognostic Value of Renal Hemodynamic Characteristics in Patients with Proliferative Lupus Nephritis

BACKGROUND/AIM

Previous studies showed that renal hemodynamic parameters, especially the filtration fraction (FF), are decreased in patients with active lupus nephritis (LN). In this study, we evaluate the prognostic value of renal hemodynamic function tests on the renal outcome in patients with proliferative LN.

METHODS

We performed a retrospective cohort study of our patients with proliferative LN from 1986 to 2005. Glomerular filtration rate (GFR) and FF before treatment were measured. Treatment failure was defined as a renal relapse or development of end-stage renal disease.

RESULTS

Thirty-seven patients were included. The median follow-up period was 8 years. Creatinine clearance, GFR, and FF before treatment correlated with the creatinine clearance at the end of follow-up (p = 0.001, p = 0.006, and p = 0.04, respectively). The FF was decreased in 92% of our patients, but FF and GFR did not have a prognostic value with regard to treatment failure.

CONCLUSIONS

Most patients with proliferative LN had a low FF. Low GFR and FF at baseline were correlated with a worse renal function at the end of follow-up, but this had no prognostic value in individual patients.

EULAR recommendations for the management of systemic lupus erythematosus. Report of a Task Force of the EULAR Standing Committee for International Clinical Studies Including Therapeutics

OBJECTIVE

Systemic lupus erythematosus (SLE) is a complex disease with variable presentations, course and prognosis. We sought to develop evidence-based recommendations addressing the major issues in the management of SLE.

METHODS

The EULAR Task Force on SLE comprised 19 specialists and a clinical epidemiologist. Key questions for the management of SLE were compiled using the Delphi technique. A systematic search of PubMed and Cochrane Library Reports was performed using McMaster/Hedges clinical queries' strategies for questions related to the diagnosis, prognosis, monitoring and treatment of SLE. For neuropsychiatric, pregnancy and antiphospholipid syndrome questions, the search was conducted using an array of relevant terms. Evidence was categorised based on sample size and type of design, and the categories of available evidence were identified for each recommendation. The strength of recommendation was assessed based on the category of available evidence, and agreement on the statements was measured across the 19 specialists.

RESULTS

Twelve questions were generated regarding the prognosis, diagnosis, monitoring and treatment of SLE, including neuropsychiatric SLE, pregnancy, the antiphospholipid syndrome and lupus nephritis. The evidence to support each proposition was evaluated and scored. After discussion and votes, the final recommendations were presented using brief statements. The average agreement among experts was 8.8 out of 10.

CONCLUSION

Recommendations for the management of SLE were developed using an evidence-based approach followed by expert consensus with high level of agreement among the experts.

Standardised assessment of membrane proteinase 3 expression. Analysis in ANCA-associated vasculitis and controls

OBJECTIVES

Increased numbers of neutrophils expressing proteinase 3 on their membrane (mPR3) have been reported in anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) and are suggested to be involved in AAV immunopathogenesis. In most studies, neutrophils were analysed for mPR3 expression without priming with TNFalpha, suggesting that mPR3 expression on neutrophils is dependent on other priming events, such as isolation procedures . These priming events can be variable. Therefore, we analysed mPR3 expression on neutrophils before and after priming with TNFalpha to assess whether standardised assessment of mPR3 expression requires priming. Using neutrophils before and after priming with TNFalpha, we assessed percentages of mPR3(+) neutrophils in patients with AAV and in disease and healthy controls.

METHODS

Neutrophils from patients with PR3-AAV and MPO-AAV, systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), and from healthy controls were analysed before and after priming with TNFalpha for mPR3 expression.

RESULTS

42% of all individuals analysed showed minimal expression for mPR3 on all neutrophils before priming with TNFalpha, whereas after priming a clear mPR3(+) subset was observed next to mPR3(-) neutrophils, corresponding to bimodal mPR3 expression. In patients with PR3-AAV or MPO-AAV, the percentage of mPR3(+) neutrophils after priming with TNFalpha was significantly increased (p<0.01 and p<0.05, respectively) compared with healthy controls. Percentages of mPR3(+) PMN were also increased in patients with SLE (p<0.01) but not in RA.

CONCLUSION

Standardised assessment of proteinase 3 on the membrane of neutrophils requires priming with TNFalpha. Percentages of mPR3(+) PMN are increased in AAV and SLE, but not in RA.

Staphylococcal toxic-shock-syndrome-toxin-1 as a risk factor for disease relapse in Wegener's granulomatosis

OBJECTIVES

Nasal carriage of Staphylococcus aureus constitutes a risk factor for disease exacerbation in Wegener's granulomatosis (WG). We hypothesized that staphylococcal superantigens (SAg) are a determinant of S. aureus-related risk for disease relapse in WG.

METHODS

In a retrospective longitudinal cohort study in 62 WG patients, we investigated the presence of the staphylococcal SAg genes sea, seb, sec, sed, see, tsst-1 and eta in S. aureus strains isolated from WG patients during an observation period of seven years. Subsequently, we assessed whether relapses of WG were associated with the presence of SAg-positive staphylococci.

RESULTS

Of 1718 swab cultures analysed, 709 (41.2%) were S. aureus-positive. Fifty-one patients carried S. aureus, of whom 37 (72.5%) patients carried at least one SAg-positive S. aureus strain. Of the 709 S. aureus-positive cultures, 326 (46%) contained at least one SAg gene. Except for see, all assessed SAg genes were detected. sea was found most frequently, followed by sec, tsst-1 and eta and finally, by sed and seb. Using a multivariate, time-dependent Cox regression analysis we found that the presence of S. aureus was associated with relapses of WG (RR 3.2; 95% CI 1.2-8.4). The risk for relapse was modulated by the presence and type of SAg, with tsst-1 being associated with an increased risk for relapse (RR 13.3, 95% CI 4.2-42.6).

CONCLUSION

The risk for relapse of WG increases with the presence of tsst-1-positive S. aureus. Eradication of tsst-1-positive S. aureus in WG may show whether disease relapses can be prevented.

Epstein-Barr virus-DNA load monitoring late after lung transplantation: a surrogate marker of the degree of immunosuppression and a safe guide to reduce immunosuppression

BACKGROUND

Posttransplant lymphoproliferative disease (PTLD) is a serious complication after lung transplantation and its relation with Epstein-Barr virus (EBV) is well recognized. It has been postulated that preemptive reduction of immunosuppression guided by EBV-DNA load may lead to a significantly lower incidence of PTLD, because of the reconstitution of T-cell control. In this report, we describe the feasibility of this approach in terms of safety with regard to the risk of acute as well as chronic allograft rejection in 75 lung transplant recipients transplanted between 1990 and 2001 and followed for this study from June 1, 2001 until January 1, 2006.

METHODS

From all patients visiting our outpatient clinic, EBV-DNA load was measured at least twice a year during the study period. In patients with positive results, measurements were repeated every two to four weeks. EBV reactivation was defined as two consecutive EBV-DNA load measurements with a rising trend; with the last measurement exceeding 10.000 copies/mL under stable immunosuppression. In such case, immunosuppression was reduced.

RESULTS

EBV reactivation was observed in 26/75 patients (35%). One (1.5%) of these patients developed PTLD during the study period. Acute rejection, acceleration of chronic allograft rejection, or worse survival were not observed after reduction of immunosuppression.

CONCLUSIONS

Preemptive reduction of immunosuppression after lung transplantation guided by EBV-DNA load appears to be a safe approach for the prevention of PTLD in lung transplant recipients late after transplantation.

Parotid gland biopsy compared with labial biopsy in the diagnosis of patients with primary Sjogren's syndrome

OBJECTIVE

To assess the value of the parotid biopsy as a diagnostic tool for primary Sjögren's syndrome (pSS), and to compare the parotid biopsy and the labial biopsy with regard to diagnostic value and biopsy-related morbidity.

METHODS

In 15 consecutive patients with pSS and 20 controls, the parotid biopsy was assessed as a diagnostic tool based on the presence of lymphocytic foci, benign lymphoepithelial lesions and lymphoid follicles. These new histological criteria were compared with established diagnostic criteria for the labial biopsy in 35 consecutive patients suspected for pSS who underwent simultaneous biopsies from both sites. In addition, both biopsies were compared for morbidity.

RESULTS

The first analysis revealed a focus score of >or=1 or lymphocytic infiltrates (not fulfilling the criterion of a focus score of 1) combined with benign lymphoepithelial lesions as diagnostic criteria for pSS. When comparing the parotid biopsy with the labial biopsy sensitivity and specificity were comparable (sensitivity 78%, specificity 86%). Level of pain was comparable and no loss of motor function was observed. No permanent sensory loss was observed after parotid biopsy, while labial biopsy led to permanent sensory loss in 6% of the patients. Malignant lymphoma was detected in one parotid biopsy by chance, without involvement of the labial salivary gland.

CONCLUSION

A parotid biopsy has a diagnostic potential comparable with that of a labial biopsy in the diagnosis of pSS, and may be associated with less morbidity.

Mechanisms of Disease: pathogenesis and treatment of ANCA-associated vasculitides

Wegener's granulomatosis and microscopic polyangiitis are idiopathic systemic vasculitides strongly associated with antineutrophil cytoplasmic autoantibodies (ANCA). In Wegener's granulomatosis, ANCA are mostly directed against proteinase 3 (PR3), whereas in microscopic polyangiitis ANCA are directed against myeloperoxidase; increases in levels of these autoantibodies precede or coincide with clinical relapses in many cases. In vitro, ANCA can further activate primed neutrophils to release reactive oxygen species and lytic enzymes, and, in conjunction with neutrophils, can damage and lyse endothelial cells. Patients with Wegener's granulomatosis or microscopic polyangiitis have an increased percentage of neutrophils that constitutively express PR3 on their membrane. These neutrophils can be stimulated by ANCA, without priming. In vivo, transfer of splenocytes from myeloperoxidase-deficient mice immunized with mouse myeloperoxidase into wild-type mice resulted in pauci-immune systemic vasculitis. A similar experiment in PR3-deficient mice did not cause significant vasculitic lesions. Together, clinical, in vitro and in vivo experimental data support a pathogenic role for ANCA in Wegener's granulomatosis and microscopic polyangiitis, although this role is more evident for myeloperoxidase-specific ANCA than for PR3-specific ANCA. Several controlled trials have led to an evidence-based approach for the treatment of ANCA-associated vasculitis, and further studies, based on new insights into pathogenesis, are in progress.

Quantitation of autoantibodies in systemic autoimmune diseases: clinically useful?

Serial assessment of levels of autoantibodies has been proposed as being clinically useful in certain systemic autoimmune diseases. In particular, attention has been given to anti-dsDNA antibodies in systemic lupus erythematosus (SLE) and ANCA in the ANCA-associated vasculitides (AAV). Much controversy exists, however, concerning the value of serial testing in these diseases. We here review the various tests available for quantitation of anti-dsDNA and ANCA, and their capacity to detect changes in autoantibody levels that are associated with changes in clinical disease activity of the respective diseases. It is concluded that changes in anti-dsDNA as measured by the Farr assay and changes in ANCA as assessed by ELISA have predictive value for the occurrence of disease relapses, although this relationship is far from absolute. Consequently, treatment based on changes in levels of the respective autoantibodies only seems at present not justified, in view of the toxicity of currently available immunosuppressive regimens.

Functional defect of circulating regulatory CD4+ T cells in patients with Wegener's granulomatosis in remission

OBJECTIVE

Accumulating data support the role of regulatory T cells, a subset of CD4+ T cells that expresses CD25(high) and the transcription factor forkhead box P3 (FoxP3), in controlling and preventing autoimmunity. In Wegener's granulomatosis (WG), an autoimmune vasculitis, up-regulation of CD25 on circulating CD4+ T cells has been observed, even in patients in remission. The objective of this study was to test whether the frequency and/or function of Treg cells from WG patients in remission are disturbed.

METHODS

Peripheral blood mononuclear cells were freshly isolated from 52 WG patients in remission and from 27 age- and sex-matched healthy control subjects. The proportion of circulating Treg cells was assessed by flow cytometry using CD4, CD25, FoxP3, and CD45RO markers. Anergy and suppressive function of CD25(high),CD4+ T cells were determined using polyclonal stimulants and coculture assay in 10 WG patients in remission and in 10 age- and sex-matched healthy controls.

RESULTS

In WG patients, a significant increase was observed in the percentage of circulating CD25(high),CD4+ and CD25(low),CD4+ T cells, whereas CD25-,CD4+ T cells were decreased, as compared with healthy controls. Among circulating CD4+ T cells, an expanded percentage of Treg cells (CD25(high),FoxP3+) with memory phenotype was present in WG patients. However, when the suppressive function of CD25(high),CD4+ T cells was tested, CD25(high),CD4+ T cells from WG patients showed diminished or absent suppression of responder T cell proliferation. The impaired suppression was not due to responder cell resistance (as shown by crisscross experiments with T cells from healthy controls) or altered survival of Treg cells.

CONCLUSION

These data indicate that WG patients in remission have an expanded proportion of Treg cells that are functionally defective. This observation may be relevant to the development and relapsing course of this autoimmune vasculitis.

Opsonization of late apoptotic cells by systemic lupus erythematosus autoantibodies inhibits their uptake via an Fcγ receptor–dependent mechanism

OBJECTIVE

Decreased clearance of apoptotic cells is suggested to be a major pathogenic factor in systemic lupus erythematosus (SLE). The aim of this study was to investigate whether the binding of SLE autoantibodies to apoptotic cells influences the phagocytosis of these cells by macrophages.

METHODS

Apoptosis was induced in a human T cell line (Jurkat) and a keratinocyte cell line (HaCaT) by ultraviolet B irradiation. Binding of purified IgG from 26 SLE patients and 15 healthy controls to apoptotic cells was assessed by flow cytometry and Western blotting. Phagocytosis of IgG-opsonized apoptotic cells by monocyte-derived macrophages was assessed by light microscopy. Similar experiments were performed with a monoclonal antibody against SSA/Ro and IgG fractions from 5 patients with Sjögren's syndrome (SS) and 5 patients with rheumatoid arthritis (RA).

RESULTS

IgG fractions from all 26 SLE patients bound to late apoptotic, but not early apoptotic, cells. IgG fractions isolated from SLE patients with different autoantibody profiles showed comparable levels of binding. IgG fractions from healthy controls did not bind. Opsonization of apoptotic cells with IgG fractions from SLE patients resulted in a significant inhibition of phagocytosis as compared with healthy control IgG fractions. A monoclonal antibody directed against SSA/Ro and IgG isolated from 5 antinuclear antibody (ANA)-positive patients with SS were also able to elicit these effects, whereas IgG from 5 ANA-negative patients with RA did not. The inhibitory effect of patient IgG was abolished by blocking either the Fcgamma receptors (FcgammaR) or the constant region of IgG, using a specific Fc-blocking peptide.

CONCLUSION

Autoantibodies from SLE patients are able to opsonize apoptotic cells and inhibit their uptake by macrophages via an FcgammaR-dependent mechanism.

Plasma levels of soluble interleukin 2 receptor, soluble CD30, interleukin 10 and B cell activator of the tumour necrosis factor family during follow-up in vasculitis associated with proteinase 3-antineutrophil cytoplasmic antibodies: associations with disease activity and relapse

OBJECTIVES

To evaluate whether T cell activation, as reflected by levels of soluble interleukin 2 receptor (sIL2R), soluble CD30 (sCD30), IL-10 and B cell activator of the tumour necrosis factor family (BAFF) at diagnosis and during initial follow-up, is predictive for persistent or renewed antineutrophil cytoplasmic antibody (ANCA) positivity and clinical relapse in patients with vasculitis associated with proteinase 3-antineutrophil cytoplasmic antibodies (PR3-ANCA).

METHODS

87 Patients with PR3-ANCA-associated vasculitis and at least 2 years of follow-up were included in the study. At diagnosis, and at 3, 6, 12, 18 and 24 months after diagnosis, cytoplasmic ANCA titres were detected by indirect immunofluorescence (IIF), and PR3-ANCA, sIL2R, sCD30, IL-10 and BAFF levels were assessed by ELISA. 31 healthy volunteers provided plasma samples for comparison. Levels of immune markers were related to ANCA positivity and relapse during follow-up.

RESULTS

Plasma levels of sIL2R, sCD30 and BAFF were higher in patients than in controls at all time points. Plasma levels of sIL2R, sCD30 and IL-10 were higher at diagnosis and relapse than during remission. At 18 months, sCD30 (p<0.001) and sIL2R levels (p = 0.01) were significantly higher in PR3-ANCA-positive patients (detected by ELISA) than in PR3-ANCA-negative patients. ANCA-positive patients detected by ELISA or IIF at 24 months had significantly higher plasma sCD30 levels (p = 0.02 and p = 0.03, respectively) than ANCA-negative patients.

CONCLUSION

Increased T cell activation in patients with ANCA-associated vasculitis in remission during and after immunosuppressive treatment is associated with persistent or renewed ANCA positivity.

Influenza vaccination in systemic lupus erythematosus: safe and protective?

Patients with systemic lupus erythematosus (SLE) show decreased immune responsiveness and are vulnerable for infectious diseases, due to the underlying disease and the frequent use of immunosuppressive drugs. Influenza has a high incidence in the population and is associated with increased morbidity and mortality in immunocompromised patients. Therefore, routine influenza vaccination of SLE patients seems indicated. However, there have been concerns about the safety of influenza vaccination in SLE as vaccination was thought to activate the autoimmune response. Safety of influenza vaccination has been studied, and, as far as SLE patients with quiescent disease are concerned, it is now generally accepted that influenza vaccination is safe. Another point of concern is vaccine efficacy. In immunocompromised patients, the immunogenicity of vaccines may be reduced. In the immune response to influenza (vaccination) both humoral and cell-mediated responses are involved. In SLE, research on the immune response to influenza vaccination has focused on humoral immune responses, demonstrating a blunted humoral response. Future research should focus on cell-mediated immune responses as well, as these are important for clearing of influenza infection and are expected to be impaired in SLE. Because of the decreased immunogenicity of the current influenza vaccine in SLE, new influenza vaccination strategies should be explored to improve vaccination efficacy.

Persistent expansion of CD4+ effector memory T cells in Wegener's granulomatosis

In order to test the hypothesis that Wegener's granulomatosis (WG) is associated with an ongoing immune effector response, even in remission, we examined the distribution of peripheral naive and memory T-lymphocytes in this disease, and analyzed the function-related phenotypes of the memory T-cell population. Peripheral blood mononuclear cells (PBMCs) were freshly isolated from WG-patients in remission (R-WG, n=40), active WG-patients (A-WG, n=17), and age-matched healthy controls (HCs, n=21). Expression of CD4, CD8, CD45RO, CCR7, interleukin (IL)-18Ralpha, ST2L, and FoxP3 were determined by four-color flow cytometric analysis. CD45RO and CCR7 were used for distinction between naive and memory T cells, IL-18Ralpha, ST2L, and FoxP3 for the assessment of Type1, Type2, and regulatory T-cells, respectively. In R-WG, the CD4+CD45RO+CCR7- effector memory T-cell subpopulation (TEM) was relatively increased, whereas the CD4+CD45RO-CCR7+ naive T-cell population (TNaive) was decreased as compared to HC. The distribution of naive and memory CD8+T cells did not differ between R-WG, A-WG, and HC, nor did CD4+CD45RO+CCR7+ central memory T cells (TCM). In contrast to HC, the percentage of CD4+TNaive cells in R-WG correlated negatively with age, whereas CD4+TEM cells showed a positive correlation. In R-WG, a skewing towards Type2 T cells was observed in CD4+TEM cells. No differences were detected in FoxP3+CD4+TEM cells between R-WG and A-WG, whereas the FoxP3-CD4+TEM cells were increased in R-WG and decreased in A-WG as compared to HC. Collectively, peripheral blood homeostasis of CD4+T cells is disturbed in R-WG with the persistent expansion of non-regulatory CD4+TEM cells. These cells might be involved in relapse and may constitute a target for therapy.

Activation, apoptosis, and clearance of neutrophils in Wegener's granulomatosis

Wegener's granulomatosis (WG) is strongly associated with the presence of antineutrophil cytoplasmic autoantibodies (ANCAs). Within WG these ANCAs are usually (80-90%) directed against the azurophilic enzyme proteinase 3, the so called PR3-ANCA. A pathophysiological role for these autoantibodies, supported by numerous in vitro and in vivo studies, is specifically based on their capacity to bind and activate neutrophils and potentially may damage vessels. In this review, the pathogenic potential of different developmental stages of the neutrophil in the pathogenesis of WG is discussed. After release from the bone marrow into the circulation, neutrophils can be primed by TNFalpha and become attached to locally activated endothelium. Once attached to the endothelium, ANCAs can fully activate these primed neutrophils. In this activation process, the degree of activation after stimulation with PR3-ANCAs associates with the level of PR3 expression on the membrane of the neutrophil. Following activation, infiltrated neutrophils become apoptotic with further membrane expression of PR3. In WG patients, clearance of apoptotic neutrophils can be disturbed due to the opsonization of PR3-expressing apoptotic neutrophils with PR3-ANCAs, thereby perpetuating inflammation by the release of proinflammatory cytokines during clearance; or it may favor autoimmunity by PR3 presentation in an inflammatory environment. Furthermore, the presence of ANCAs and the release of the vessel-related pentraxin PTX3 may lead to the persistence of late apoptotic neutrophils in tissues, thereby inducing leukocytoclastic lesions that are characteristic in patients with WG. All together, alive neutrophils as well as apoptotic neutrophils play a key role in different inflammatory phenomena seen in patients suffering from WG.

Progression of salivary gland dysfunction in patients with Sjogren's syndrome

BACKGROUND

Salivary gland dysfunction is one of the key manifestations of Sjögren's syndrome.

OBJECTIVES

(1) To assess prospectively loss of function of individual salivary glands in patients with primary and secondary Sjögren's syndrome in relation to disease duration and use of immunomodulatory drugs. (2) To study changes in sialochemical and laboratory values and subjective complaints over time.

METHODS

60 patients with Sjögren's syndrome were included in this study. Whole and gland-specific saliva (parotid and submandibular/sublingual (SM/SL)), samples were collected at baseline and after a mean of 3.6 (SD 2.3) years of follow-up. Disease duration was recorded for all patients.

RESULTS

Patients with Sjögren's syndrome with short disease duration had significantly higher stimulated flow rates at baseline than those with longer disease duration (p<0.05). When compared with healthy controls, the decrease in SM/SL flow rates at baseline was more prominent than that in parotid flow rates (p<0.05). Over time, there was a significant further decrease of stimulated flow rates, especially of the parotid gland, accompanied by increasing problems with swallowing dry food (p<0.05). The decrease was independent of the use of corticosteroids or disease-modifying antirheumatic drugs (DMARDs). Sialochemical variables remained stable.

CONCLUSIONS

Early Sjögren's syndrome is characterised by a decreased salivary gland function (parotis>SM/SL), which shows a further decrease over time, regardless of the use of DMARDs or steroids. Patients with Sjögren's syndrome with longer disease duration are characterised by severely reduced secretions of both the parotid and SM/SL glands. These observations are relevant for identifying patients who would most likely benefit from intervention treatment.

Abundance of the long pentraxin PTX3 at sites of leukocytoclastic lesions in patients with small-vessel vasculitis

OBJECTIVE

The prototypical tissue pentraxin PTX3 inhibits phagocytosis of late apoptotic polymorphonuclear leukocytes (PMNs) by macrophages. Levels of PTX3 parallel disease activity in small-vessel vasculitis. Small-vessel vasculitis is often characterized by leukocytoclasia, a phenomenon of accumulation of nuclear remnants from unscavenged PMNs in or near the vessel wall. We therefore hypothesized that PTX3 accumulates at sites of leukocytoclastic vasculitis and, as such, is a key factor for the induction of leukocytoclasis.

METHODS

We examined skin biopsy samples from 13 patients with small-vessel vasculitis and from 4 healthy and 3 inflammatory skin disease controls. Biopsy tissues, characterized histopathologically as leukocytoclastic vasculitis, were studied for the presence of PTX3 using rabbit anti-PTX3 polyclonal antibodies. Sections were scored morphometrically for leukocytoclastic infiltrates in conjunction with PTX3 staining. Morphometric scores were expressed as percentages of staining of the total tissue area.

RESULTS

Biopsy specimens from patients with leukocytoclastic vasculitis revealed an abundant up-regulation of PTX3 at sites of leukocytoclastic infiltrates. Significantly more PTX3 was found in tissues from the 13 patients with vasculitis (mean +/- SEM 48.9 +/- 6.1%) than in tissues from the 7 controls (4.5 +/- 2.7%) (P = 0.0003). PTX3 was localized around vessels, as well as spread diffusely throughout the tissue.

CONCLUSION

PTX3 is abundantly present at sites of leukocytoclastic infiltrates in patients with small-vessel vasculitis, but not in controls. Since PTX3 inhibits phagocytosis of late apoptotic PMNs by macrophages and is strongly up-regulated at sites of leukocytoclastic infiltration, PTX3 is a candidate factor in the phenomenon of leukocytoclasia in small-vessel vasculitis.

Prediction of relapses in PR3-ANCA-associated vasculitis by assessing responses of ANCA titres to treatment

OBJECTIVE

We performed a retrospective evaluation of whether c-ANCA titres (indirect immunofluorescence) and anti-proteinase 3 (PR3)-ANCA levels (ELISA) at diagnosis and following immunosuppressive treatment are predictive of relapse of ANCA-associated vasculitis.

METHODS

Patients diagnosed with PR3-ANCA-associated vasculitis between 1991 and 2002, with at least 2 yr of follow-up, and treated with cyclophosphamide and corticosteroids only (1991-1996) or switched to azathioprine after induction of remission with cyclophosphamide and corticosteroids (1997-2002) were included. ANCA were assessed by immunofluorescence and direct PR3-specific ELISA at diagnosis and 3, 6, 12, 18 and 24 months after diagnosis. Actuarial relapse-free survival was analysed with the log rank test.

RESULTS

We studied 87 patients positive for PR3-ANCA: 46 were on cyclophosphamide maintenance therapy and 41 switched to azathioprine. Overall actuarial relapse-free survival was 72% at 2 yr and 34% at 5 yr. Relapse-free survival did not differ between patients on cyclophosphamide maintenance and patients switched to azathioprine maintenance (P = 0.34). Patients who became and stayed negative for c-ANCA (immunofluorescence) or PR3-ANCA (ELISA) until 24 months after diagnosis had a lower risk of relapse (P = 0.01 and P = 0.02, respectively). Positive c-ANCA (immunofluorescence) titres at 3 [relative risk (RR) 2.0; 95% confidence interval (CI) 1.2-3.8], 12 (RR 1.9; 95% CI 1.1-3.3), 18 (RR 2.9; 95% CI 1.3-4.6) and 24 months (RR 2.6; 95% CI 1.2-5.0) were significantly associated with relapse within 5 yr after diagnosis. PR3-ANCA levels >10 U/ml at 18 (RR 2.7, 95% CI 1.1-4.3) and 24 months (RR 4.6; 95% CI 1.2-6.3) were predictive of relapse within 5 yr. In the azathioprine group, a positive c-ANCA titre at the time of switching to azathioprine (RR 2.2; 95% CI 1.0-5.4) was associated with relapse.

CONCLUSION

Positive c-ANCA (immunofluorescence) and PR3-ANCA (ELISA) titres during early follow-up identify patients at increased risk of relapse.

Skin sensitivity to UVB irradiation in systemic lupus erythematosus is not related to the level of apoptosis induction in keratinocytes

OBJECTIVES

Accumulation of apoptotic cells has been suggested to be involved in the pathogenesis of systemic lupus erythematosus (SLE). As sunlight exposure is one of the factors that can trigger disease activity, we hypothesized that UV light may induce increased numbers of apoptotic cells in SLE.

METHODS

Fourteen SLE patients and 16 controls were irradiated with UVB to determine their minimal erythemal dose (MED). Subsequently, skin was irradiated with 1 MED and 2 MED, respectively, and after 24 h skin biopsies were analysed immunohistologically for the number of apoptotic cells and presence of pyknotic nuclear debris.

RESULTS

MED was significantly decreased in SLE patients and the presence of decreased MED was associated with a history of butterfly rash. Decreased MED was not related to other skin-related ACR criteria or to autoantibody specificities. No differences were detected in the numbers of apoptotic keratinocytes between patients and controls or in the amount of pyknotic nuclear debris following 1 and 2 MED irradiation, respectively. Absolute UVB doses were correlated with the number of apoptotic keratinocytes; dose-responses did not differ significantly between patients and controls.

CONCLUSIONS

Increased sensitivity of SLE patients to UVB, although associated with a history of malar rash, is not related to increased induction of apoptosis or increased levels of secondary necrosis in the skin. Thus, compared with controls, UVB-induced apoptosis is not increased in SLE patients under physiological conditions.

Safety and efficacy of influenza vaccination in systemic lupus erythematosus patients with quiescent disease

OBJECTIVE

to assess the safety and efficacy of influenza vaccination in patients with systemic lupus erythematosus (SLE), and to evaluate the influence of immunosuppressive drugs on the immune response.

METHODS

SLE patients (n=56) and healthy controls (n=18) were studied. All patients had quiescent disease (SLE disease activity index<or=5). Four patient groups were defined on the basis of their drug use: (1) no drug treatment; (2) hydroxychloroquine treatment; (3) azathioprine treatment; (4) prednisone treatment. Participants received trivalent influenza subunit vaccine during October/November 2003. Disease activity scores and side effects were recorded. Antibody titres against influenza virus were measured before and 30 days after vaccination using the haemagglutination inhibition assay.

RESULTS

Influenza vaccination did not result in changes in disease activity and was well tolerated. SLE patients had fewer seroconversions or fourfold titre rises for A/H1N1 (p<0.001) and A/H3N2 (p<0.001) than healthy controls, while for B/Hong Kong the difference was of borderline significance (p=0.051). With regard to immunosuppressive treatment, fewer SLE patients using azathioprine developed fourfold titre rises against A/H3N2 (p=0.041), and fewer achieved titres of >or=40 against A/H3N2 (p=0.030) compared with the other patient groups.

CONCLUSIONS

Influenza vaccination in SLE patients with quiescent disease is safe but is less effective than in controls. Use of azathioprine was associated with a trend to decreased vaccination efficacy.

Current status of outcome measures in vasculitis: focus on Wegener's granulomatosis and microscopic polyangiitis. Report from OMERACT 7

The complexity of assessing disease activity, disease status, and damage in the vasculitides reflects the multisystemic pathologic manifestations of these often chronic illnesses. Major progress has been made in the past decade in the development of validated and widely accepted outcome measures for use in clinical trials. Over time, these tools have been regularly revised, expanded, and supplemented with new measures of disease prognosis and damage. As a result clinical research in this area has become increasingly complex. This article critically reviews the current status of tools for assessing disease activity and damage in "ANCA-associated" vasculitides (Wegener's granulomatosis and microscopic polyangiitis), summarizes the current level of validation of each measure, addresses central problems and controversies to be considered during development of new vasculitis assessment tools, and proposes a series of research agendas for consideration by the vasculitis research community.

Human anti-neutrophil cytoplasm autoantibodies to proteinase 3 (PR3-ANCA) bind to neutrophils

BACKGROUND

Recently, the in vivo pathogenic role of anti-neutrophil cytoplasm autoantibodies (ANCA) in ANCA-associated vasculitis has been challenged by Abdel-Salam et al. In their report, they observed that ANCA directed against proteinase 3 (PR3) cannot bind to their target autoantigen PR3 on circulating neutrophils (PMN). Here we present evidence that human PR3-ANCA do specifically bind to PMN that express PR3 on their membrane.

METHODS

PMN were isolated from donors showing bimodal membrane PR3 expression on their PMN (N= 3). TNFalpha-primed PMN or PMA-stimulated PMN were incubated with serum or plasma from PR3-ANCA-positive patients with Wegener's granulomatosis (WG) (N= 8) or healthy controls (N= 8). Binding of IgG in serum or plasma samples to PMN was assessed by indirect immunofluorescence.

RESULTS

Binding of IgG in undiluted plasma or serum from PR3-ANCA-positive WG-patients to PMN was significantly increased compared to plasma or serum from healthy controls. Dilution of plasma and serum showed concentration-dependent binding of IgG. Double staining for PR3 and IgG demonstrated that IgG in plasma or serum from PR3-ANCA-positive patients only bound to those PMN that expressed PR3, and not to PMN that lacked PR3 expression on their membrane.

CONCLUSION

PR3-ANCA in undiluted serum or plasma from PR3-ANCA-positive WG patients bind to TNFalpha- primed and PMA-stimulated PMN that express PR3 on their membrane. Therefore, the hypothesis that PR3-ANCA can bind and activate primed PMN is still the most attractive explanation for the contribution of PR3-ANCA to the pathogenesis of Wegener's granulomatosis.

Levels of complement in sera from inactive SLE patients, although decreased, do not influence in vitro uptake of apoptotic cells

BACKGROUND

Accumulation of apoptotic cells is considered relevant in the pathogenesis of systemic lupus erythematosus (SLE). Complement factors facilitate the clearance of apoptotic cells and, when decreased, might result in an increased amount of apoptotic cells found in SLE patients.

OBJECTIVE

To determine the influence of complement profiles from inactive SLE patients on the in vitro phagocytosis of apoptotic cells.

METHODS

Consecutive SLE patients (n=98) with inactive disease (SLEDAI < or =4) and 20 healthy controls (HC) were included. Levels of CH50, C3, C4, C1q, and C1r were measured. Human peripheral blood monocytes were isolated from healthy controls and cultured for 7 days to obtain monocyte-derived macrophages (MDM). Jurkat cells were irradiated with UVB to induce apoptosis. Phagocytosis was tested by incubation of MDM with apoptotic cells in the presence of serum and quantified as phagocytosis index (number of Jurkat cells internalized by 100 macrophages). Serum from 20 patients with CH50<65%, 20 patients with CH50 > or =65%, and 20 HC were used in this assay.

RESULTS

All HC and 37% of patients had normal complement levels. CH50 level was decreased in 21% of patients, C3 in 52%, C4 in 29%, C1q in 2% and C1r in 44% of patients. Between patients and HC, differences in level of CH50, C3 and C4 were statistically significant. No difference in phagocytosis index between HC and patients, irrespective of their CH50 level, was detected. No correlation was found between the respective complement levels and phagocytosis index.

CONCLUSION

In most SLE patients with inactive disease, levels of one or more complement components are decreased. However, decreased levels of complement do not result in a significantly reduced in vitro uptake of apoptotic Jurkat cells by MDM.

Apoptosis in Human Skin: Role in Pathogenesis of Various Diseases and Relevance for Therapy

Cell death by apoptosis is a physiological process that enables the elimination of cells without causing an inflammatory response. In self-renewing tissue like the epidermal layers of the skin, cell numbers are tightly regulated by a delicate balance between proliferation, differentiation, and cell death. Besides cell death by terminal differentiation in normal skin, cell death can also be induced by exposure to sunlight. This paper will review the different forms of cell death in the skin and discuss the role of apoptosis in diseases like skin cancer, psoriasis, and systemic lupus erythematosus.

Reduced uptake of apoptotic cells by macrophages in systemic lupus erythematosus: correlates with decreased serum levels of complement

BACKGROUND

Defects in phagocytosis of apoptotic cells have a role in the pathogenesis of autoimmune diseases. Decrease of phagocytosis of apoptotic cells occurs in systemic lupus erythematosus (SLE). Factors underlying this decrease are, presently, unknown.

OBJECTIVE

To analyse the expression of relevant membrane receptors of monocyte derived macrophages (MDM) from patients with SLE and assess their ability to phagocytose apoptotic cells in comparison with MDM from healthy controls. Additionally, to compare phagocytosis in the presence of SLE sera with that in normal human serum (NHS).

METHODS

Human peripheral blood monocytes were isolated from patients and controls, and cultured for 7 days to obtain MDM. Membrane expression of CD14, CD18, CD36, and CD51/61 was measured. MDM were incubated with apoptotic Jurkat cells in the presence of NHS or serum from patients with active or inactive disease.

RESULTS

No differences in phagocytosis capacity were found between MDM from patients and controls. Membrane expression of the respective receptors was comparable in patients and controls. However, when MDM from controls were incubated with apoptotic cells in patient serum, phagocytosis was significantly decreased in comparison with incubation in NHS. This effect depended on the patients' disease activity and could be reversed by addition of NHS. Reduced uptake of apoptotic cells was associated with decreased levels of complement C1q, C4, and C3, but not with levels of complement factor B.

CONCLUSIONS

Reduced uptake of apoptotic cells by MDM from patients with SLE is not an intrinsic defect but is serum dependent and associated with decreased levels of C1q, C4, and C3.

Association of common cold with exacerbations in pediatric but not adult patients with tic disorder: a prospective longitudinal study

Cross-sectional data and case studies suggest a temporal relationship between fluctuations in tic severity and preceding infections. In this study, we aimed to examine this possible relationship in a prospective longitudinal design. Two groups of tic disorder patients were included, a pediatric group between 7 and 15 years of age (n = 20), and an adult group over 15 years of age (n = 41). During a 24-week period, participants were asked to fill out weekly self questionnaires regarding the presence of tic exacerbations and the experience of the common cold. In addition, 6 throat swabs were taken at monthly intervals and cultured for streptococci; also, 3 serial serum assessments of streptococcal antibodies were performed at 8-week intervals. In the pediatric group, our results indicated a strong association between the self report of a common cold and a symptom exacerbation 4 weeks later (Odds ratio = 4.685; p = 0.001). In the adult group, we found no association between reports of common cold and tic exacerbations. Association with streptococcal infections could not be determined owing to the limited number of observed streptococcal infections. Thus, this study points to a hitherto unknown association of common viral infections with tic exacerbations in children, which may support the involvement of immune dysregulation in tic disorders.

Rituximab treatment in patients with primary Sjögren's syndrome: An open-label phase II study

OBJECTIVE

To investigate the safety and efficacy of B cell depletion treatment of patients with active primary Sjögren's syndrome of short duration (early primary SS) and patients with primary SS and mucosa-associated lymphoid tissue (MALT)-type lymphoma (MALT/primary SS).

METHODS

Fifteen patients with primary SS were included in this phase II trial. Inclusion criteria for the early primary SS group were B cell hyperactivity (IgG >15 gm/liter), presence of autoantibodies (IgM rheumatoid factor, anti-SSA/SSB), and short disease duration (<4 years). Inclusion criteria for the MALT/primary SS group were primary SS and an associated MALT-type lymphoma (Ann Arbor stage IE) localized in the parotid gland. Patients were treated with 4 infusions of rituximab (375 mg/m2) given weekly after pretreatment with prednisone (25 mg) and clemastine. Patients were evaluated, using immunologic, salivary/lacrimal function, and subjective parameters, at baseline and at 5 and 12 weeks after the first infusion.

RESULTS

Significant improvement of subjective symptoms and an increase in salivary gland function was observed in patients with residual salivary gland function. Immunologic analysis showed a rapid decrease of peripheral B cells and stable levels of IgG. Human anti-chimeric antibodies (HACAs) developed in 4 of 15 patients (27%), all with early primary SS. Three of these patients developed a serum sickness-like disorder. Of the 7 patients with MALT/primary SS, complete remission was achieved in 3, and disease was stable in 3 and progressive in 1.

CONCLUSION

Findings of this phase II study suggest that rituximab is effective in the treatment of primary SS. The high incidence of HACAs and associated side effects observed in this study needs further evaluation.

Changes in salivary gland immunohistology and function after rituximab monotherapy in a patient with Sjogren's syndrome and associated MALT lymphoma

OBJECTIVES

To report the successful use of rituximab on salivary gland immunohistology and function in a patient with Sjogren's syndrome (SS) and associated MALT lymphoma.

CASE REPORT

The patient was a 42 year old woman with primary SS and associated MALT lymphoma located in the parotid gland and the hard palate. Four infusions of rituximab (375 mg/m(2)) weekly resulted in complete remission of the lymphoma. An incision biopsy of the parotid gland before and after treatment showed improvement of the (immuno)histopathological characteristics of SS, with possible regeneration of salivary gland tissue. Furthermore, salivary analysis showed decreased inflammatory characteristics and increased stimulated salivary flow.

DISCUSSION

Rituximab is a promising agent in the treatment of SS associated MALT lymphoma. In addition to the effect on MALT lymphoma, B cell depletion by rituximab may also attenuate the activity of SS. This case report is the first to describe the effect of rituximab on histological and sialometric/chemical characteristics of SS. The efficacy of rituximab in the treatment of SS warrants further investigation.

B cell epitope specificity in ANCA-associated vasculitis: does it matter?

Pauci-immune idiopathic small-vessel vasculitis is strongly associated with the presence of antineutrophil cytoplasm autoantibodies (ANCA). Antibodies to PR3 predominate in patients with Wegener's granulomatosis; antibodies to myeloperoxidase (MPO) are found more frequently in patients with microscopic polyangiitis. There is increasing in vivo and in vitro evidence for a pathogenic role of ANCA in systemic vasculitis based on associations of ANCA with disease activity. If ANCA are pathogenic, why is the course of disease different from one patient to another? Antibodies can recognize different binding sites (epitopes) on their corresponding antigens. Differences in binding specificity may influence the pathogenic potential of the antibodies. Differences between epitope specificity of ANCA between patients or changes in epitope specificity of ANCA in time in an individual patient may, accordingly, result in differences in disease expression. This review will focus on epitope specificity of autoantibodies in systemic autoimmune diseases and especially on the epitope specificity of PR3- and MPO-ANCA. We will discuss whether PR3-ANCA or MPO-ANCA recognize different epitopes on PR3 and MPO, respectively, and whether the epitopes recognized by ANCA change in parallel with the disease activity of ANCA-associated vasculitis. Finally, we will speculate if the direct pathogenic role of ANCA can be ascribed to one relapse- or disease-inducing epitope. Characterization of relapse- or disease-inducing epitopes bound by PR3-ANCA and MPO-ANCA is significant for understanding initiation and reactivation of ANCA-associated vasculitis. Elucidating a disease-inducing epitope bound by ANCA may lead to the development of epitope-specific therapeutic strategies.

Diversity of PR3-ANCA epitope specificity in Wegener's granulomatosis. Analysis using the biosensor technology

Wegener's granulomatosis is a systemic disease characterized by the presence of antineutrophil cytoplasm autoantibodies specific for proteinase 3 (PR3-ANCA). The functional characteristics of PR3-ANCA differ between quiescent and active disease, suggesting changes in the properties of the autoantibodies in time. Using biosensor technology, we found that PR3-ANCA of different patients (n = 8) recognize a limited number of overlapping regions on PR3 at the time of diagnosis of Wegener's granulomatosis. This area might cover an immunodominant epitope, common for PR3-ANCA from all patients, irrespective of the size of the total area recognized by an individual autoantibody. Experiments with sera (n = 4) collected at the moment of diagnosis and at the time of relapse showed that the individual epitope specificities of PR3-ANCA change during the course of the disease. These changes in epitope specificity of PR3-ANCA may be responsible for the differences in functional properties of these autoantibodies between various stages of the disease.

The prototypic tissue pentraxin PTX3, in contrast to the short pentraxin serum amyloid P, inhibits phagocytosis of late apoptotic neutrophils by macrophages

OBJECTIVE

Phagocytosis of apoptotic cells can be facilitated by complement components and short pentraxins, such as serum amyloid P (SAP). In contrast, the long pentraxin PTX3 was shown to inhibit phagocytosis of apoptotic Jurkat cells by dendritic cells and to bind late apoptotic polymorphonuclear leukocytes (PMNs). Recently, levels of the pentraxin PTX3 were shown to parallel disease activity in small-vessel vasculitis, which is often characterized by leukocytoclasia, a persistence of leukocyte remnants in the vessel wall. We undertook this study to test our hypothesis that PTX3 inhibits phagocytosis of late apoptotic PMNs by macrophages, thereby leading to their accumulation in the vessel wall.

METHODS

Macrophages were allowed to phagocytose late apoptotic or secondary necrotic PMNs that were incubated with or without PTX3 for 30 minutes prior to phagocytosis. Phagocytosis was allowed to occur in the presence of 30% normal human serum with or without SAP and with or without depletion of complement. To discriminate between an inhibitory effect of PTX3 on binding and the internalization of apoptotic PMNs into macrophages, internalization was blocked by cytochalasin B.

RESULTS

SAP and complement were both necessary for effective in vitro phagocytosis. In contrast, PTX3 inhibited phagocytosis in a dose-dependent manner, from 11% inhibition at 6.25 microg/ml to almost complete inhibition at 100 microg/ml. Furthermore, PTX3 partly affected binding of apoptotic PMNs to macrophages.

CONCLUSION

PTX3, in contrast to SAP and complement, inhibits phagocytosis of late apoptotic PMNs by monocyte-derived macrophages in a dose-dependent manner. Therefore, PTX3 can play a role in the development of leukocytoclasia by affecting the clearance of apoptotic PMNs, thereby inducing their accumulation in the vessel wall.