Urinary monocyte chemoattractant protein-1 (MCP-1) is a marker of active renal vasculitis

BACKGROUND

Macrophage infiltration and cytokine production are important in the pathogenesis of crescentic glomerulonephritis in anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis. The aim of this study was to investigate whether urinary levels of chemokines, monocyte chemoattractant protein-1 (MCP-1) and fractalkine, were useful tools for non-invasive assessment of renal vasculitis.

METHODS

In a prospective study, concentrations of chemokines were measured in urine and serum samples using specific enzyme-linked immunosorbent assays, and related to the patients' clinical status. Renal expression of MCP-1 was studied by immunohistochemical staining of renal biopsies.

RESULTS

Urinary levels of MCP-1 were significantly higher in patients with active (P<0.01) or persistent (P<0.05) renal vasculitis, in comparison with healthy volunteers, control patients, patients with inactive vasculitis and patients with extra-renal disease only. There were no differences in serum concentrations of MCP-1 between these groups. Reduction in urinary MCP-1 levels following treatment preceded the improvement of renal function by a median of 2 weeks. In one patient, rising urinary levels of MCP-1, despite immunosuppressive therapy, was associated with progression to severe renal failure. There were no differences in urinary fractalkine levels between the different groups of patients and controls. Immunohistology of renal biopsies from patients with crescentic glomerulonephritis showed increased staining for MCP-1 in glomerular and interstitial cells. Urinary MCP-1 levels correlated with glomerular, but not tubulointerstitial, macrophage infiltration (P<0.05).

CONCLUSIONS

This study shows that measurement of urinary MCP-1, but not fractalkine, is a useful non-invasive technique for the assessment of renal involvement and monitoring the response to therapy in ANCA-associated vasculitis.

Serum amyloid P component levels are not decreased in patients with systemic lupus erythematosus and do not rise during an acute phase reaction

BACKGROUND

Serum amyloid P component (SAP) and acute phase proteins like C-reactive protein contribute to the clearance of apoptotic cells. This response is diminished in systemic lupus erythematosus (SLE).

OBJECTIVES

To analyse SAP concentrations in SLE in relation to disease activity, and investigate whether SAP reacts like an acute phase protein.

METHODS

SAP was measured in 40 patients with SLE during active and inactive disease and compared with healthy controls and patients with rheumatoid arthritis and Wegener's granulomatosis. Normal SAP values were determined in 120 healthy controls by ELISA. C reactive protein and serum amyloid A (SAA) were measured in all subjects and their levels related to SAP. SAP was also measured serially in 11 patients with breast cancer treated with recombinant human interleukin-6, and in 16 patients with sepsis.

RESULTS

In SLE, SAP was unaltered compared with healthy controls and was not influenced by disease activity, in contrast to C reactive protein and SAA, which increased during active disease. SAP increased in Wegener's granulomatosis but not in rheumatoid arthritis. The rise in C reactive protein and SAA was most pronounced in Wegener's granulomatosis with active disease. SAP did not change significantly during an acute phase response. No correlation was found between SAP and C reactive protein or SAA, but there was a correlation between SAA and C reactive protein (r = 0.4989, p = 0.0492).

CONCLUSIONS

Patients with SLE have normal circulating SAP levels. In contrast to C reactive protein or SAA, SAP does not act as an acute phase protein.

Constitutive membrane expression of proteinase 3 (PR3) and neutrophil activation by anti-PR3 antibodies

Antineutrophil cytoplasm autoantibodies with specificity for proteinase 3 (PR3) are thought to play a major role in the pathogenesis of Wegener's granulomatosis (WG), presumably by their potential to activate neutrophils. In patients with WG, high expression of PR3 on the surface of nonprimed neutrophils is associated with an increased incidence and rate of relapse. In this study, we analyzed the functional significance of constitutive PR3 expression for neutrophil activation as induced by anti-PR3 antibody. Therefore, primed and nonprimed neutrophils were stimulated with the monoclonal anti-PR3 antibody PR3G-3. Activation was measured as actin polymerization by the phalloidin assay as an early, detectable activation event and oxidative burst by the dihydrorhodamine assay, as a late, detectable activation event. In contrast to the oxidative burst, we found that anti-PR3 antibody-induced actin polymerization could be triggered in neutrophils without priming with tumor necrosis factor alpha (TNF-alpha). In addition, a correlation was found between the level of PR3 expression on the surface of these nonprimed neutrophils and the degree of actin polymerization. However, after priming with TNF-alpha, no correlation was found between membrane expression of PR3 and the level of actin polymerization or respiratory burst as induced by anti-PR3 antibody. These data suggest that the presence of PR3 on the surface of nonprimed neutrophils has consequences for their susceptibility to the initial activation step by anti-PR3 antibodies. These data may be relevant in view of the observed relation between membrane expression of PR3 on nonprimed neutrophils of patients with WG and their susceptibility for relapses.

Molecular genetic analyses of human NKG2C (KLRC2) gene deletion

Human NKG2A, NKG2C and NKG2E genes are located on 12p13 in the NK gene complex. We recently identified deletion of NKG2C in a Japanese population. This study was performed to identify the breakpoint, and to examine the association of NKG2C deletion with susceptibility to rheumatoid arthritis and systemic lupus erythematosus. The location of the breakpoint was determined to be 1.5-1.8 kb telomeric from the 3' end of NKG2A by comparing sequences of the intergenic segments upstream and downstream of the NKG2C gene in the common haplotype with the intergenic sequence between NKG2A and NKG2E in the deletion haplotype. Based on this information, a genotyping system was developed. The frequency of NKG2C deletion haplotype was 20.2% in Japanese and 20.0% in Dutch populations. The frequency of homozygous deletion was 4.1% in Japanese and 3.8% in Dutch. Evidence for an association with rheumatic diseases was not detected. These results indicated that NKG2C deletion is commonly present in Japanese and Dutch, suggesting that NKG2C is not essential for survival and reproduction, and is not associated with rheumatic diseases.

Relative contribution of attention-deficit hyperactivity disorder, obsessive-compulsive disorder, and tic severity to social and behavioral problems in tic disorders

The aim of this study was to investigate social and behavioral problems related to attention-deficit hyperactivity disorder (ADHD), obsessions and compulsions, and tic severity in children with a tic disorder. Parents of 58 children with a tic disorder with and without different forms of ADHD completed the Child Behavior Checklist (CBCL) and the Children's Social Behavior Questionnaire. Patients with a tic disorder with primarily hyperactive-impulsive ADHD had the highest questionnaire scores, patients with primarily inattentive ADHD had medium scores, and patients without ADHD had the lowest scores. On most subscales, significant part correlations with ADHD severity, but not tic severity, were obtained. Severity of obsessions and compulsions was independently correlated with the CBCL Thought Problems subscale but not with most other subscales. There was no significant correlation between tic severity and ADHD severity. Thus, in patients with a tic disorder, the presence and severity of ADHD are the main predictors of associated behavioral and social problems.

The Th1 and Th2 paradigm in ANCA-associated vasculitis

In the pathogenesis of anti-neutrophil cytoplasm antibodies (ANCA)-associated vasculitis, T cell contribution is indicated by T cell-dependent ANCA production combined with the presence of T cells in inflammatory infiltrates. However, the exact pathogenic role of T cells in ANCA-associated vasculitis remains to be determined. The Th1/Th2 concept is useful for understanding T cell involvement in pathological processes. This review focuses on T cells and particularly the Th1/Th2 paradigm in ANCA-associated vasculitis. Most research has been done in Wegener's granulomatosis, where a shift in T cell response, from a Th1 pattern in localized disease towards a Th0/Th2 pattern in generalized disease, appears to occur. Although less thoroughly studied, data in Churg-Strauss syndrome and microscopic polyangiitis indicate that these diseases are predominantly associated with Th2 patterns. Further studies elucidating the true nature of the polarization towards Th1 or Th2 in ANCA-associated vasculitis are clearly needed.

Lack of effect of intravenous immunoglobulins on tics: a double-blind placebo-controlled study

BACKGROUND

Case studies and a placebo-controlled study previously suggested the effectiveness of immunomodulatory therapy in patients with tic or related disorders whose symptoms show a relationship with streptococcal infections. No data are available on the effectiveness of intravenous immunoglobulins (IVIG) on tic severity in unselected tic disorder patients.

METHOD

Thirty patients with a DSM-IV tic disorder were randomly assigned to IVIG (1 g/kg on 2 consecutive days; mean age = 28.71 years; range, 14-53 years) or placebo (mean age = 30.73 years; range, 14-63 years). Symptoms were rated with the Yale Global Tic Severity Scale, the Yale-Brown Obsessive Compulsive Scale, and the Clinical Global Impressions scale of symptom change with regard to tic severity. These were used at baseline and on weeks 2, 4, 6, 10, and 14 posttreatment, after which blinding was broken. The study was conducted from March through August 2002.

RESULTS

We observed no significant differences between both treatment groups regarding posttreatment changes in tic severity. Severity of obsessions and compulsions, which was in the subclinical range, decreased significantly in the IVIG group compared with the placebo group at week 6 (p =.02). Then, there was a 32.3% improvement in the IVIG group compared with baseline. Though this improvement was maintained over the following 8 weeks, no statistically significant differences between the IVIG and the placebo group with regard to improvements in obsessions and compulsions were detected at subsequent assessments. IVIG treatment was associated with significantly more side effects than placebo, most notably headache.

CONCLUSION

Based on the present results, IVIG cannot be recommended in tic disorders.

Neurobiology and neuroimmunology of Tourette?s syndrome: an update

Tourette's syndrome is a childhood-onset neuropsychiatric disorder characterized by the presence of both multiple motor and vocal tics. While the pathogenesis at a molecular and cellular level remains unknown, structural and functional neuroimaging studies point to the involvement of the basal ganglia and related cortico-striato-thalamo-cortical circuits as the neuroanatomical site for Tourette's syndrome. Moreover, Tourette's syndrome has a strong genetic component, and considerable progress has been made in understanding the mode of transmission and in identifying potential genomic loci. Summaries of recent findings in these areas will be reviewed, followed by a critical overview of findings both supporting and challenging the proposed autoimmune hypothesis of Tourette's syndrome. We conclude that Tourette's syndrome is a heterogeneous disorder, and that immune factors may indeed be involved in some patients.

Renal expression of matrix metalloproteinases in human ANCA-associated glomerulonephritis

BACKGROUND

Expression of matrix metalloproteinases (MMPs) by infiltrating and intrinsic renal cells is increased in inflammatory conditions, and may correlate with disease activity of glomerulonephritis. We analysed renal expression of MMPs, tissue inhibitor of metalloproteinase-1 (TIMP-1) and markers of neutrophil and monocyte infiltration in renal biopsies of patients with active anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis.

METHODS

Immunohistochemical expression of MMP-2, -3, -9, TIMP-1, the neutrophil- and monocyte-derived MMP activators cathepsin G, neutrophil elastase and myeloperoxidase (MPO), and the monocyte marker CD14 was determined in renal biopsies of active proteinase 3 (PR3)-ANCA (n = 7) and MPO-ANCA (n = 6) associated glomerulonephritis, and in normal renal tissue (n = 4). Double labelling experiments of MMPs and TIMP-1 were performed with MPO and CD68, labelling neutrophils and macrophages.

RESULTS

MMP-2-, MMP-3-, MMP-9- and TIMP-1-positive cells were detected in ANCA-associated glomerulonephritis in glomeruli with active inflammation (cellular crescents or fibrinoid necrosis), only occasionally in normal appearing glomeruli, and not in sclerotic glomeruli and positive cells were found in the tubulo-interstitium. MMPs and TIMP-1 were expressed predominantly by MPO-and CD68-positive cells. In normal renal tissue, no expression was detected, with the exception of weak mesangial staining for MMP-2. In ANCA-associated glomerulonephritis, glomerular MMP-2, -9 and TIMP-1 correlated with glomerular cathepsin G expression, while the number of MMP-9-expressing cells per glomerulus correlated with the percentage of crescentic glomeruli. Tubulo-interstitial expression of MMPs correlated with all markers of neutrophil and monocyte infiltration, and interstitial MMP-9 and TIMP-1 expression correlated with renal function at the time of renal biopsy.

CONCLUSIONS

Expression of glomerular and interstitial MMP-2, -3, -9 and TIMP-1 is increased in active ANCA-associated glomerulonephritis and correlates with inflammatory activity.

Association of small life events with self reports of tic severity in pediatric and adult tic disorder patients: a prospective longitudinal study

BACKGROUND

Clinical experience suggests an association between stressful life events and fluctuations in symptom severity of tic disorder patients. The aim of the present study was to examine this possible relationship in a prospective longitudinal design.

METHOD

Two groups of patients with tic disorder according to the research criteria of the Tourette Syndrome Classification Study Group were included in this study (Sept. 2001 through March 2002): a pediatric group aged from 7 through 16 years (N = 25) and an adult group aged 18 years and older (N = 32). During a 12-week period, participants were asked weekly to fill out questionnaires regarding the occurrence of small life events and self ratings of tic severity.

RESULTS

Twenty-four of 25 patients in the pediatric group completed the study, and 28 of 32 patients in the adult group completed the study and reported at least 1 life event. In the adult group as a whole, we found a weak but statistically significant correlation between negative small life events and tic severity during the same week (r = 0.268, p <.001). However, only a minority of individual pediatric (21%) and adult (18%) patients demonstrated significant relationships between the frequency of small life events and tic severity in the same week or 1 week later (p </=.05), with undesirable small life events positively associated with tic severity in some patients and negatively associated with tic severity in other patients.

CONCLUSION

Contrary to traditional views, in general, life events do not account for changes in tic severity. Only in a minority of tic disorder patients do fluctuations in symptom severity appear to be associated with possibly stressful small life events.

Risk factors for relapse in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis: tools for treatment decisions?

Current treatment based on the use of cyclophosphamide and corticosteroids has changed anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides from highly fatal into more chronic relapsing diseases. Relapses are a major problem in these diseases and cause increased morbidity and mortality. Current clinical research mainly focuses on achieving control of active disease while minimizing treatment-related toxicity. Risks for longterm relapse and their sequelae have been less thoroughly studied. It is noteworthy that, besides treatment, several other factors have been associated with the occurrence of relapses. Thus, compared to MPO-ANCA positive patients, patients with PR3-ANCA associated vasculitis run a significantly increased risk of experiencing relapses. ANCA-status during follow-up, levels of T cell activation, genetic background, and infectious and other exogenous factors have been linked to relapse as well. With a few exceptions, these associations are merely descriptive and not pathophysiologically proven. Furthermore, data on adapting treatment in accordance with risk factors for relapse are scarce. We review here the risk factors for relapse in ANCA-associated vasculitis, their potential pathogenic implications, and their possible role in preventive strategies and adaptations of current treatment policies.

Evaluation of capture ELISA for detection of antineutrophil cytoplasmic antibodies directed against proteinase 3 in Wegener's granulomatosis: first results from a multicentre study

OBJECTIVE

To evaluate the performance characteristics of direct and capture ELISA for the detection of PR3-ANCA in Wegener's granulomatosis (WG) in international ANCA reference laboratories.

METHODS

Serum samples were derived from patients with histological and clinical diagnosis of WG (n = 60), rheumatoid arthritis (RA) (n = 30) and healthy controls (n = 30). Each of them was tested for the presence of ANCA by indirect immunofluorescence technique (IFT), direct and capture ELISA in six international reference laboratories (Massachusetts General Hospital, Boston; Wieslab AB, Lund; University of Maastricht; University Hospital Groningen; Mayo Clinic, Rochester; Rheumaklinik Bad Bramstedt/University of Schleswig-Holstein Campus Lübeck). Each centre tested the sera according to their house protocols of IFT and ELISA. The diagnostic performance of each test was estimated by receiver operating characteristic curve analysis and sensitivity and specificity in detection of ANCA/PR3-ANCA were calculated for the respective methods.

RESULTS

In patients histologically and clinically known as WG, the detection of ANCA by IFT varied between 52 and 83% among the participating centres. PR3-ANCA positivity with the different ELISAs ranged from 53 to 80% in direct ELISA and from 72 to 76% in capture ELISA. While most capture ELISAs successfully detected PR3-ANCA, there were significant differences between IFT and direct ELISA results between laboratories. ROC curve analysis demonstrated that in five of six laboratories the overall diagnostic performance of capture ELISA was superior to IFT and direct ELISA, respectively.

CONCLUSION

Capture ELISA is a highly sensitive assay for detection of PR3-ANCA in WG and should be used in conjunction with compatible clinical picture and histological evidence.

Fcgamma receptors in the initiation and progression of systemic lupus erythematosus

Systemic lupus erythematosus, a systemic autoimmune disorder, is characterized by the production of autoantibodies to nuclear constituents and inflammatory lesions in multiple organ systems. Although the pathogenesis of the disease is largely unknown, recent studies have suggested that disturbances in apoptosis and/or clearance of apoptotic cells may play an important role in the induction and perpetuation of autoantibody production. When autoantibodies subsequently complex to autoantigens present on apoptotic cells, ligation of Fcgamma receptor will result in inflammation and disease development. Indeed, mice deficient in activating Fcgamma receptors were protected against inflammation in models of immune complex-mediated autoimmune disease, whereas deletion of the inhibitory Fcgamma receptors increased autoantibody production and susceptibility to immune complex-induced inflammation. Additionally, functional polymorphisms in Fcgamma receptors were shown to be associated with development of human systemic lupus erythematosus. This review focuses on the role of Fcgamma receptors in the initiation of autoantibody production, inflammatory handling of immune complexes, and disease development in systemic lupus erythematosus.

Comparison of lacrimal and salivary gland involvement in Sjögren's syndrome

OBJECTIVES

To determine the performance of different tear and salivary tests applied in Sjögren's syndrome (SS) and to disclose how these tests relate to common serologic tests in SS.

DESIGN

In addition to the routine ocular and oral tests for diagnosing SS (Schirmer test, rose bengal score, unstimulated whole saliva flow, and parotid sialography), tear breakup time and flow rate of glandular saliva (parotid and submandibular-sublingual [SM/SL]) were evaluated in patients referred for diagnosis of SS. Patients were categorized into primary SS, secondary SS, and non-SS groups according to the revised European classification criteria for SS.

SETTING

Referral center.

PATIENTS

Referred sample of 80 consecutive patients.

MAIN OUTCOME MEASURE

Correlation between ocular and salivary measures.

RESULTS

Breakup time performed insufficiently in diagnosing SS, as opposed to the rose bengal score. In patients with primary and secondary SS, a clear correlation was noted between tear and saliva quality and secretion rate, and between the rose bengal score and parotid sialography. Increased rose bengal scores also correlated significantly with hyperglobulinemia and presence of SS-B antibodies in serum, with duration of subjective eye dryness, and with decreased tear-gland function. With regard to the oral tests, whole, parotid, and SM/SL salivary flow decreased significantly with increasing duration of oral complaints, with the stimulated SM/SL flow rate showing the strongest decrease and being more specific in diagnosing SS. Also, parotid sialography was more specific in excluding patients without SS than the commonly applied diagnostic criterion of secretion of unstimulated whole saliva.

CONCLUSIONS

The rose bengal score remains the eye test of choice, as it has the highest specificity for SS. Hyperglobulinemia and especially positive serologic findings for SS-B may warrant close monitoring of the eyes, since these serum findings appear to relate to the severity of ocular surface damage. Parotid sialography and stimulated secretion of SM/SL saliva are more specific in diagnosing SS than unstimulated secretion of whole saliva.

Increased seroreactivity in tic disorder patients to a 60 kDa protein band from a neuronal cell line

In tic disorders, increased seroreactivity against neuronal antigens has been demonstrated, without performing molecular characterization of antigens. Here, unselected patients with a tic disorder were compared with healthy controls, autistic disorder (AD), and obsessive-compulsive disorder (OCD) patients. Seroreactivity against neuroblastoma cells was analyzed by Western blot. Anti-60 kDa binding occurred significantly more frequently in tic disorder patients (67.1%) than in AD (40.0%), OCD (40.0%) and healthy controls (41.9%). Sequence analysis of the 60 kDa protein band identified this as a ubiquitous heat shock protein. However, the involvement of other autoantigens with a molecular weight of 60 kDa cannot be excluded.

Neutrophil-activating potential of antineutrophil cytoplasm autoantibodies

Accumulating in vivo and in vitro evidence supports the hypothesis that antineutrophil cytoplasm autoantibodies (ANCA) with specificity for proteinase 3 (PR3) and myeloperoxidase (MPO) are involved in the pathophysiology of small-vessel vasculitis. The best-described effector function of these autoantibodies is stimulation of neutrophils to produce reactive oxygen species and to release proteolytic enzymes. Neutrophil activation requires interaction of monomeric ANCA with PR3/MPO and Fcgamma receptors, but also other mechanisms--for instance, stimulation by ANCA-containing immune complexes--cannot be excluded. This review focuses on the mechanisms of neutrophil activation by ANCA. We discuss the molecules involved in ANCA binding to the neutrophil surface and in triggering the functional responses. We summarize current knowledge on the signal-transduction pathways initiated by ANCA and on the factors determining susceptibility of neutrophils to activation by these autoantibodies.

Role of the Fcgamma receptor IIA polymorphism in the antiphospholipid syndrome: an international meta-analysis

OBJECTIVE

To assess the impact of the FcgammaRIIA-R/H131 polymorphism on the risk for antiphospholipid syndrome (APS), both primary and secondary to systemic lupus erythematosus (SLE).

METHODS

This international meta-analysis combined data from 9 research teams. FcgammaRIIA-R/H131 genotypes were determined in 481 APS cases (206 with primary APS), 1,420 SLE controls, and 1,655 disease-free controls. Data were combined using fixed-effects and random-effects models.

RESULTS

Compared with disease-free controls, the RR genotype was enriched in the entire group of APS cases (odds ratio [OR] 1.65, 95% confidence interval [95% CI] 1.28-2.14); this was driven mostly by patients with secondary APS (OR 1.95, 95% CI 1.45-2.63). The excess of RR homozygotes but not heterozygotes among APS patients suggested a recessive mode of inheritance, rather than the additive model seen for SLE susceptibility, where RR conferred greatest risk, and RH intermediate risk, for SLE. This probably reflected the additional influence of another opposing genetic effect of HH homozygosity on APS predisposition (OR 0.72 for RH versus HH, 95% CI 0.55-0.96). Among SLE patients, those with APS were more frequently HH homozygotes than heterozygotes (OR 0.56 for RH versus HH, 95% CI 0.39-0.81). HH homozygosity also tended to predominate in primary APS compared with secondary APS (OR 0.50 for RR versus HH, 95% CI 0.25-0.99 by fixed-effects model). There was no significant between-study heterogeneity for any of these effects.

CONCLUSION

The FcgammaRIIA-R/H131 polymorphism is an important determinant of predisposition to APS, with different influences on SLE and APS susceptibility per se.

Mycophenolate mofetil prevents a clinical relapse in patients with systemic lupus erythematosus at risk

BACKGROUND

Systemic lupus erythematosus (SLE) is characterised by the presence of antibodies to double stranded DNA (dsDNA), which are involved in the pathogenesis of SLE. Previous studies showed that at least two thirds of patients develop a clinical relapse within six months after a significant rise in the anti-dsDNA level, and most relapses were prevented by the administration of corticosteroids at the time of the rise.

OBJECTIVE

To determine whether mofetil mycophenolate (MMF) can prevent a clinical relapse without the side effects associated with corticosteroids.

METHODS

36 patients with SLE were examined monthly to determine whether a rise in anti-dsDNA level had occurred. A rise was defined as an increase of 25% of the level of the previous sample of at least 15 IU/ml within a four month period. After a rise patients were treated with MMF 2000 mg daily for six months. Patients were monitored monthly for the occurrence of a clinical relapse and to assess the serological activity and state of activation of CD4+, CD8+, and CD19+ lymphocyte subsets.

RESULTS

Anti-dsDNA rose in 10 patients. Treatment with MMF was started in all these patients, and after six months no clinical relapse had occurred. Side effects were minimal. Antibodies to dsDNA decreased during the treatment (p<0.001), associated with a decrease in the state of activation of CD19+ lymphocytes. No changes were found in the state of activation of CD4+ or CD8+ lymphocyte subsets.

CONCLUSION

Administration of MMF after a rise in antibodies to dsDNA is well tolerated, decreases anti-dsDNA and B cell activation, and seems to prevent the occurrence of a clinical relapse in patients with SLE.

Staphylococcal superantigens and T cell expansions in Wegener's granulomatosis

In Wegener's granulomatosis (WG), a form of autoimmune systemic vasculitis, chronic carriage of Staphylococcus aureus constitutes a risk factor for the development of exacerbations. Circulating T cells in this disease are persistently activated, suggesting the presence of a chronic stimulus. A causal link between chronic carriage of S. aureus and chronic T cell activation in WG is conceivable, because S. aureus produces superantigens (SAg), which are potent T cell stimulators. Superantigenic stimulation of T cells results in expansion of T cell subsets expressing SAg-binding T cell receptor V-beta (Vbeta) chains. In the present study we hypothesized that in WG the presence of staphylococcal SAg is accompanied by expansion of SAg-reacting T cell subsets. We tested our hypothesis in a cross-sectional and a longitudinal study in which the association between seven staphylococcal SAg genes [typed by poplymerase chain reaction (PCR)], eight SAg-binding Vbeta chains and four SAg-non-binding Vbeta chains (assessed by flow-cytometry) was assessed. Both studies showed that T cell expansions were present at a significantly higher rate in WG patients than in healthy individuals, but were not associated with the presence of either S. aureus or its SAg. Moreover, T cell expansions were generally of small extent, and did not appear simultaneously in both CD4 and CD8 subsets. We conclude that in WG S. aureus effects its supposed pathogenic function by a mechanism other than superantigenic T cell activation.

Image analysis: a novel approach for the quantification of antineutrophil cytoplasmic antibody levels in patients with Wegener's granulomatosis

Rises in antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) have predictive potential for a relapse of Wegener's granulomatosis (WG). To assess the value of image analysis for monitoring ANCA levels, we measured PR3-ANCA in a cohort of PR3-ANCA positive patients with WG that were prospectively followed in our clinic and compared findings with other techniques. ANCA levels were measured serially by quantitative image analysis, titration in indirect immunofluorescence (IIF), two different directly coated antigen-specific enzyme-linked immunosorbent assays (ELISA), and a capture ELISA using a PR3-specific monoclonal antibody in 16 consecutive WG patients prior to a renal relapse, and in 16 age- and sex-matched patients with inactive WG. The positive predictive value (PPV) of an increase in ANCA titers by image analysis for relapse was 69% (11 of 16). The PPV of an increase in ANCA was 61% (11 of 18) by IIF, 71% (12 of 17) by a commercial direct ELISA, 63% (12 of 19) by in-house direct ELISA, and 75% (12 of 16) by capture ELISA. The negative predictive value (NPV) of the absence of an increase in ANCA titers by image analysis for relapse was 69% (11 of 16). The NPV of the absence of an increase in ANCA was 64% (9 of 14) by IIF, 73% (11 of 15) by a commercial direct ELISA, 63% (9 of 13) by in-house direct ELISA, and 75% (12 of 16) by capture ELISA. In conclusions, quantitative image analysis is a novel technique based on the principle of IIF to quantify ANCA levels in a single dilution in a patient sample. No major differences were observed between image analysis and the other techniques in their capacity to predict relapses of disease activity.

Serum amyloid P component binds to late apoptotic cells and mediates their uptake by monocyte-derived macrophages

OBJECTIVE

Some pentraxins, such as C-reactive protein, bind to apoptotic cells and are involved in the clearance of these cells. We undertook this study to determine whether serum amyloid P component (SAP; a pentraxin that, when deficient in mice, results in lupus-like disease) binds to apoptotic cells and to assess the functional consequences of SAP binding for their phagocytosis by macrophages.

METHODS

Human peripheral blood monocytes were isolated and cultured for 7 days to obtain monocyte-derived macrophages. Jurkat cells were irradiated with ultraviolet B to induce apoptosis. After 4 hours, a mean +/- SEM of 54.0 +/- 5.1% of these cells stained with annexin V and were propidium iodide negative (early apoptotic [EA] cells). After 24 hours, 77.3 +/- 2.7% of cells stained positive with both annexin V and propidium iodide (late apoptotic [LA] cells or secondary necrotic cells). EA and LA cells were incubated with fluorescein isothiocyanate-labeled SAP in the presence or absence of Ca(2+), and binding was measured by flow cytometry. Phagocytosis was tested by incubation of macrophages with EA or LA cells in the presence of normal human serum (NHS) and quantified as a phagocytosis index (PI; number of Jurkat cells internalized by 100 macrophages). Experiments were repeated with SAP-depleted serum and after reconstitution with increasing concentrations of SAP.

RESULTS

The majority of LA cells did bind SAP in the presence of Ca(2+), whereas EA cells did not. SAP depletion of NHS resulted in a 50% decrease in the PI for LA cells, and complete restoration of the PI could be demonstrated with SAP reconstitution up to 100 microg/ml. SAP depletion had no effect on phagocytosis of EA cells.

CONCLUSION

SAP binds to LA cells and is involved in the phagocytosis of these cells by human monocyte-derived macrophages. This may have consequences for diseases such as systemic lupus erythematosus, in which phagocytosis of apoptotic cells is decreased.

Is Tourette's syndrome an autoimmune disease?

We provide a review of recent research findings which support the involvement of autoimmunity in childhood-onset tic disorders, in particular the presence of antineuronal autoantibodies, D8/17 B lymphocyte overexpression, a marker of chorea associated with streptococcal infection, and possible beneficial effects of immunomodulatory intervention. One of the most controversial areas in this field is the validity of the proposed PANDAS concept. Some researchers have delineated a putatively unique subgroup of patients, from the spectrum of illness encompassing Tourette's syndrome and obsessive-compulsive disorder (OCD), whose tics and obsessive-compulsive symptoms are shown to arise in response to beta-hemolytic streptococcal infections. They designated it by the term pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS). Herein we additionally present pros and cons concerning the concept of PANDAS. Finally, recommendations for future research directions are given.

Treatment of primary Sjögren's syndrome with D-penicillamine: a pilot study

BACKGROUND

Up to now no satisfying systemic treatment is available for patients with primary Sjögren's syndrome.

METHODS

In a prospective, open study we investigated the effect of D-penicillamine (first three months 250 mg/day, next three months 500 mg/day) on clinical and immunological parameters in 19 patients with primary Sjögren's syndrome and a mean disease duration of 3.8 years.

RESULTS

Eight patients had to stop treatment mainly due to severe (reversible) loss of taste. Clinically, a statistically significant increase in basal salivary flow was observed after three months (p<0.05). In addition, improvement was noted in the Schirmer test and stimulated parotid salivary flow after six months, but these differences were not statistically significant. Laboratory values showed a decrease in ESR (p<0.05) and levels of IgA and IgM (both p<0.02) after six months, a decrease in levels of IgA-Rf and IgM-Rf after three months (both p<0.05), and an increase in haemoglobin level (p<0.05).

CONCLUSION

From this pilot study we conclude that the treatment of primary Sjögren's syndrome with D-penicillamine has only marginal beneficial effects. Together with its clear side effects this means that D-penicillamine is unsuitable for this indication.

Neutrophil membrane expression of proteinase 3 (PR3) is related to relapse in PR3-ANCA-associated vasculitis

Wegener granulomatosis (WG) is strongly associated with the presence of antineutrophil cytoplasm autoantibodies (ANCA) with specificity for proteinase 3 (PR3). Relapses of WG are frequently preceded by a rise of autoantibody titer and PR3-ANCA are able to activate primed neutrophils in vitro. Except being stored intracellularly and translocated to the cell surface upon neutrophil stimulation, PR3 can also be detected on the surface of non-stimulated neutrophils (membrane PR3 or mPR3), with an interindividual variability in percentages of mPR3(-)-positive cells and level of mPR3 expression. This study began with the hypothesis that the presence of PR3 on the surface of non-stimulated neutrophils enables interaction with PR3-ANCA and influences clinical manifestations of the disease. It analyzed mPR3 expression on neutrophils of 89 WG patients in complete remission and 72 healthy controls to evaluate whether the presence of PR3 on the surface of resting neutrophils is related to clinical manifestations of WG and/or to the susceptibility to develop relapses. The number of patients with a bimodal mPR3 expression on resting neutrophils did not differ between patients and controls. However, in WG patients, an increased percentage of mPR3(+) neutrophils and an elevated level of mPR3 expression compared with healthy individuals (P = 0.037) were found. Within the group of WG patients, an elevated level of mPR3 expression was significantly associated with an increased risk for relapse (P = 0.021) and with an increased relapse rate (P = 0.011), but not with the disease extent or particular manifestations at diagnosis or at relapse. These data support the hypothesis that PR3 expression on the membrane of neutrophils plays a role in the pathophysiology of PR3-ANCA associated vasculitis.

Interference of PR3-ANCA with the enzymatic activity of PR3: differences in patients during active disease or remission of Wegener's granulomatosis

Anti-neutrophil cytoplasmic antibodies (ANCA) against proteinase 3 (PR3) are strongly associated with Wegener's granulomatosis (WG) and are thought to be involved in its pathogenesis. Levels of PR3-ANCA do not always correspond to clinical disease activity. To investigate the relationship between functional effects of PR3-ANCA and disease activity, we tested the effect of IgG samples from sera of 43 WG patients, taken during active disease or remission, for their capacity to interfere with the proteolytic activity of PR3. Furthermore, longitudinal sera of seven WG patients were included. The enzymatic activity of PR3 was determined (1) with casein or with a small synthetic substrate and (2) by complexation of PR3 with alpha1-antitrypsin (alpha1-AT). With a fixed concentration (100 microg/ml) of IgG, PR3-ANCA from patients during an active phase of WG had a higher inhibitory capacity towards the proteolytic activity of PR3 and complexation of PR3 with alpha1-AT than did PR3-ANCA from WG patients during remission. However, the number of PR3-ANCA units that gave 50% inhibition of the PR3 enzymatic activity and its complexation with alpha1-AT was lower for patients during remission than for patients during an active phase of WG, indicating a stronger inhibitory capacity at a molar base. In conclusion, PR3-ANCA from patients during remission had a relatively higher inhibitory capacity towards the enzymatic activity of PR3 than PR3-ANCA from patients during an active phase. This may indicate that during active disease the ANCA titre is increased, but the number of active ANCA molecules that recognize the enzyme-inhibiting epitopes is not increased.

In vitro cytokine production and proliferation of T cells from patients with anti-proteinase 3- and antimyeloperoxidase-associated vasculitis, in response to proteinase 3 and myeloperoxidase

OBJECTIVE

To investigate in vitro proliferative responses of CD4+ T cells and generation of specific cytokines induced by stimulation of peripheral blood mononuclear cells (PBMCs) from patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis with the autoantigens proteinase 3 (PR3) and myeloperoxidase (MPO).

METHODS

PBMCs from vasculitis patients with PR3 ANCA or MPO ANCA and from healthy controls were stimulated for 7 days with PR3, MPO, or control stimuli. Proliferation of CD4+ T cells was assessed by flow cytometry, using the proliferation marker Ki-67. Levels of the pro-proliferative cytokines interleukin-2 (IL-2) and IL-6 and of the Th1 and Th2 cytokines interferon-gamma (IFN gamma) and IL-10 in culture supernatants were determined.

RESULTS

PR3 and MPO induced proliferative responses in CD4+ T cells from individual patients with ANCA-associated vasculitides and healthy controls in vitro. Neither PR3 nor MPO elicited significant IL-2 production. Levels of IL-6 were highest after stimulation with PR3 but low after stimulation with MPO, independent of study group. Stimulation with PR3, and to a lesser extent with MPO, induced a Th2 cytokine milieu, characterized by high production of IL-6 and IL-10 and low production of IFN gamma in patients and controls.

CONCLUSION

PR3 and MPO promote proliferation of CD4+ T cells from patients with ANCA-associated vasculitides, but also cross-stimulate T cells from healthy individuals. Strong IL-10 production elicited by PR3 in vitro may act as an inhibitory signal for T cell proliferation and may have an important immunoregulatory function in vivo.

Parotid sialography for diagnosing Sjögren syndrome

OBJECTIVE

Despite the availability of many new imaging procedures, sialography has, after decades of use, maintained its status as the imaging procedure of choice for evaluating the oral component of Sjögren syndrome (SS). In this study, the clinical value of sialography as a diagnostic tool in SS was explored by assessing its diagnostic accuracy, observer bias, and staging potential.

METHODS

One hundred parotid sialograms were interpreted independently in a blinded fashion by 2 trained and 2 expert observers. Sialograms were derived from a group of consecutive patients referred for diagnostics of SS. Patients were categorized as SS and non-SS by the revised European classification criteria.

RESULTS

Trained observers reached a sensitivity of 95 and a specificity of 33% for SS by sialogram, whereas expert observers reached a sensitivity of 87 and a specificity of 84%. There was only "fair" interobserver agreement between trained and expert observers, whereas both expert observers showed "good" agreement with one another, according to Cohen's kappa. Intraobserver agreement was "good" to "very good" for all observers. The 4 different gradations of sialectasia, ie, punctate, globular, cavitary, and destructive, showed a weak but significant correlation with the duration of oral symptoms.

CONCLUSIONS

This study markedly shows that the diagnostic value of parotid sialography for diagnosing SS greatly depends on the skills of the observer, implying that sialography lacks general applicability as a diagnostic tool in SS and requires specific expertise. Nevertheless, given its potentially high sensitivity and specificity in diagnosing SS as well as its useful staging potential, sialography still has its use in the evaluation of the oral component of SS.

Expression of recombinant proteinase 3, the autoantigen in Wegener's granulomatosis, in insect cells

Proteinase 3 (PR3) is the major autoantigen for anti-neutrophil cytoplasmic antibodies (ANCA) in patients with Wegener's granulomatosis. Little is known about the major antigenic sites on PR3. To facilitate epitope mapping, PR3 was cloned in insect cells using a baculovirus expression system. Four different sequences of the PR3 cDNA were amplified by PCR: two clones containing the pro-peptide of PR3 with or without a His-tag (rproPR3-his and rproPR3, respectively) and two clones without the pro-peptide and with or without a His-tag (rPR3-his and rPR3, respectively). The PR3 sequences were cloned behind the polyhedrin promoter and the honeybee melittin signal peptide enabling secretion of rPR3. Plasmids were transposed into the genome of baculovirus, and wild types as well as PR3-containing virus genomes were transfected into Sf21 insect cells. All four rPR3 variants were secreted into the medium and were recognized by anti-neutrophil PR3 rabbit serum and by at least two anti-PR3 monoclonal antibodies. Mature forms of PR3 were recognized by almost all patient sera, whereas the pro-forms of PR3 were recognized by 14 of 18 PR3-ANCA sera tested. On SDS-PAGE, the four rPR3 forms migrated at approximately 32 kDa. RPR3-his and rproPR3-his could be purified by means of this His-tag. In conclusion, especially the mature rPR3s are well recognized by PR3-ANCA sera. The presence of a C-terminal His-tag facilitated purification of His-tagged rPR3. Thus, rPR3 expressed in insect cells can be used as a tool for diagnostic tests as well as for epitope mapping studies.

Fcgamma receptor gene polymorphisms in Japanese patients with systemic lupus erythematosus: contribution of FCGR2B to genetic susceptibility

OBJECTIVE

Human low-affinity Fcgamma receptors (FcgammaR) constitute a clustered gene family located on chromosome 1q23, that consists of FcgammaRIIA, IIB, IIC, IIIA, and IIIB genes. FcgammaRIIB is unique in its ability to transmit inhibitory signals, and recent animal studies demonstrated a role for FcgammaRIIB deficiency in the development of autoimmunity. Genetic variants of FcgammaRIIA, IIIA, and IIIB and their association with systemic lupus erythematosus (SLE) have been extensively studied in various populations, but the results were inconsistent. To examine the possibility that another susceptibility gene of primary significance exists within the FcgammaR region, we screened for polymorphisms of the human FCGR2B gene, and examined whether these polymorphisms are associated with SLE.

METHODS

Variation screening of FCGR2B was performed by direct sequencing and polymerase chain reaction (PCR)-single-strand conformation polymorphism methods using complementary DNA samples. Genotyping of the detected polymorphism was done using genomic DNA, with a specific genotyping system based on nested PCR and hybridization probing. Association with SLE was analyzed in 193 Japanese patients with SLE and 303 healthy individuals. In addition, the same groups of patients and controls were genotyped for the previously known polymorphisms of FCGR2A, FCGR3A, and FCGR3B.

RESULTS

We detected a single-nucleotide polymorphism in FCGR2B, (c.695T>C), coding for a nonsynonymous substitution, Ile232Thr (I232T), within the transmembrane domain. The frequency of the 232T/T genotype was significantly increased in SLE patients compared with healthy individuals. When the same patients and controls were also genotyped for FCGR2A-131R/H, FCGR3A-176V/F, and FCGR3B-NA1/2 polymorphisms, FCGR3A-176F/F showed significant association. Two-locus analyses suggested that both FCGR2B and FCGR3A may contribute to SLE susceptibility, while the previously reported association of FCGR3B was considered to be secondary and derived from strong linkage disequilibrium with FCGR2B.

CONCLUSION

These results demonstrate the association of a new polymorphism of FCGR2B (I232T) with susceptibility to SLE in the Japanese.

Familial occurrence of autoimmune diseases and autoantibodies in a Caucasian population of patients with systemic lupus erythematosus

To determine the prevalence of autoimmune diseases and autoantibodies in relatives of Caucasian patients with systemic lupus erythematosus (SLE) we questioned 118 patients for the prevalence of autoimmune diseases in their relatives. Multicase SLE families were selected for further investigation: assessment of the presence of antinuclear antibodies (ANA), thyroid antibodies and IgM rheumatoid factor (IgM-RF). Thirty-three patients reported the presence of 50 autoimmune diseases in 43 relatives. Twenty-two diagnoses could be either confirmed (n=14) or refuted (n=8). SLE clustered significantly within families of SLE patients. Multiple sclerosis and rheumatoid arthritis also seemed to cluster within families of lupus patients. The prevalence of ANA (24%) and thyroid antibodies (44%) in 29 relatives of multicase SLE families was raised (P<0.05). In conclusion, the prevalence of autoimmune diseases is raised in relatives of Caucasian SLE patients. Also, the prevalence of autoantibodies is raised in relatives of multicase SLE families, both suggesting genetic influences in the pathogenesis of the disease. These findings support the genome-wide screening of SLE patients to unravel factors responsible for genetic susceptibility to SLE.

Oral and ocular manifestations in Sjögren's syndrome

OBJECTIVE

Little is known about the relationship between lachrymal and salivary gland involvement in Sjögren's syndrome (SS). It is also of interest to know which eye test contributes most to the diagnosis of SS. We investigated the performance of different tear tests and how these tests relate to common serologic and salivary tests in SS.

METHODS

In patients suspected of SS, the tear breakup time and the tear mucus score were evaluated in addition to the routine tests. Eighty consecutive patients were included, categorized into primary SS (pSS), secondary SS (sSS), and negative for SS.

RESULTS

The tear breakup time and mucus score both performed insufficiently in diagnosing SS, in contrast to the Rose Bengal score. In pSS and sSS patients, a clear correlation was noted between tear and saliva quality and secretion rate, and between the Rose Bengal score and parotid sialography. Increased Rose Bengal scores also correlated significantly with hyperglobulinemia and presence of SSB antibodies in serum, with duration of subjective eye dryness, and with decreased tear gland function.

CONCLUSION

The Rose Bengal score remains the eye test of choice having the highest specificity for SS. Hyperglobulinemia and especially positive SSB serology may warrant close monitoring of the eyes, since these serum findings appear to relate to the severity of ocular surface damage. Theoretically, a positive evaluation of either the ocular or oral component, in addition to positive serology or histopathology, could be sufficient to diagnose the syndrome for clinical purposes.

Patients' perceptions of the effects of systemic lupus erythematosus on health, function, income, and interpersonal relationships: a comparison with Wegener's granulomatosis

OBJECTIVE

To describe the patients' perceptions of the effects of systemic lupus erythematosus (SLE) and Wegener's granulomatosis (WG) on health, function, income, and interpersonal relationships.

METHODS

114 patients with SLE, and 79 patients with WG completed a self-administered questionnaire. Patients had been diagnosed with SLE or WG for a median period of 10 and 5 years, respectively.

RESULTS

All patients experienced substantial functional morbidity. Two-thirds of the patients with SLE or WG reported either a periodic or permanent inability to perform daily activities at home and/or at work. Furthermore, SLE as well as WG had a considerable impact upon the psychological and social life, affecting their happiness and altering relationships.

CONCLUSION

Our study demonstrates that SLE and WG are associated with substantial medical morbidity resulting in physical and occupational disability. SLE has a profound impact on patients' lives, similar to that experienced in patients with WG.

Sialometry and sialochemistry: a non-invasive approach for diagnosing Sjögren's syndrome

BACKGROUND

Analysis of salivary variables has frequently been proposed as a diagnostic tool for Sjögren's syndrome (SS). Because univocal salivary reference values are lacking, it is currently rather difficult to use sialometry and sialochemistry for diagnosing SS unless major changes have occurred in salivary secretion and composition.

OBJECTIVE

To define reference values of several salivary variables, which offer a possible new and non-invasive means of diagnosing SS.

METHODS

Cut off points were selected from receiver operating characteristic curves of gland-specific sialometrical and sialochemical variables, which have proved to be potentially relevant for diagnosing SS in a previous study-that is, sodium, chloride, and phosphate concentration in stimulated parotid and submandibular/sublingual (SM/SL) saliva, unstimulated and stimulated SM/SL flow rates, and lag phase of parotid secretion, respectively. By combining the most discriminating variables, two different diagnostic approaches for SS were applied in a group of 100 patients and subsequently evaluated in a second group of 20 patients. The first approach was to combine variables by applying their cut off points into sets of criteria for a positive diagnosis of SS. The second approach was to construct a logistic regression model that predicts the true state of a patient (SS or non-SS). From both approaches, the tests with highest likelihood ratio combined with the smallest number of rejected cases were selected for clinical use.

RESULTS

The most accurate test combined the stimulated SM/SL flow rate and parotid sodium and chloride concentration as salivary variables for diagnosing SS; it had a sensitivity of 0.85 and a specificity of 0.96. The selected tests proved equally accurate in the second group of patients.

CONCLUSIONS

Because the proposed non-invasive diagnostic tools can be easily applied, do not need a laboratory other than for routine blood testing, and are very accurate, gland-specific sialometry and sialochemistry may eventually replace other, more invasive, diagnostic techniques for diagnosing SS.

New insights into the pathogenesis of antineutrophil cytoplasmic autoantibody-associated vasculitis

Antineutrophil cytoplasmic autoantibodies (ANCA) directed to proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA) are closely associated with the idiopathic systemic necrotizing vasculitides, in particular Wegener's granulomatosis, microscopic polyangiitis and its renal limited manifestation, and Churg Strauss Syndrome. Many in vitro studies show that those ANCA have phlogistic potential, particularly at the interface of neutrophils and endothelial cells. A limited number of studies in experimental animals support their pathogenetic role. However, ANCA alone are not sufficient, as based on clinical and experimental data, and other, probably exogenous factors, seem necessary for disease induction and (re)activation. Among those silica and particularly, the carriage of Staphylococcus aureus have been proposed. Besides, various genetic factors are involved in disease susceptibility. The ANCA-associated vasculitides are systemic autoimmune diseases in which the interplay of autoimmunity with environmental and genetic factors determines their clinical expression.

IgG subclass distribution of autoantibodies differs between renal and extra-renal relapses in patients with systemic lupus erythematosus

BACKGROUND

IgG subclasses of autoantibodies differ in their potential to induce an inflammatory response as they interact differentially with complement and Fcgamma receptors.

METHODS

The IgG subclass distribution of anti-nucleohistone and anti-dsDNA antibodies was analysed longitudinally in patients with systemic lupus erythematosus before and at the moment of an extra-renal (n=23) or a renal relapse (n=l7). Kidney biopsy specimens of patients with a renal relapse were analysed for IgG subclass deposition.

RESULTS

IgG1 anti-nucleohistone and IgG1 anti-dsDNA antibodies were present in plasma of 39 out of 40 patients. At the moment of a relapse, IgG2 and IgG3 anti-nucleohistone and IgG2 anti-dsDNA antibodies were more frequently present in patients with renal disease compared with those with extra-renal disease. Increases in levels of IgG1 anti-dsDNA were observed in 10 out of 11 patients prior to a renal relapse but only 10 out of 22 patients with an extra-renal relapse (91 vs 45%, P=0.02). Rises in IgG2 anti-dsDNA occurred at an equally low rate prior to both renal and extra-renal relapses. A rise in IgG2 anti-nucleohistone antibodies preceded a renal relapse in eight of 11 patients and an extra-renal relapse in only four out of 22 patients (73 vs 18%, P=0.006). In kidney biopsies all IgG subclasses could be detected. IgG1 and IgG2 subclass antibodies to nucleohistone and to dsDNA are the predominant subclasses found in plasma of lupus patients with renal disease.

CONCLUSIONS

The frequent occurrence of a rise in IgG2 anti-nucleohistone and IgG1 anti-dsDNA in patients prior to a renal relapse suggests that, besides IgG1 subclass autoantibodies, IgG2 subclass antibodies to nucleohistone have a particular pathophysiological role in lupus nephritis.

Lack of endothelial nitric oxide synthase aggravates murine accelerated anti-glomerular basement membrane glomerulonephritis

Nitric oxide (NO) radicals generated by endothelial nitric oxide synthase (eNOS) are involved in the regulation of vascular tone. In addition, NO radicals derived from eNOS inhibit platelet aggregation and leukocyte adhesion to the endothelium and, thus, may have anti-inflammatory effects. To study the role of eNOS in renal inflammation, the development of accelerated anti-glomerular basement membrane (GBM) glomerulonephritis was examined in mice lacking a functional gene for eNOS and compared with wild-type (WT) C57BL/B6j mice. WT C57BL/6j mice (n = 12) and eNOS knockout (-/-) mice (n = 12) were immunized intraperitoneally with sheep IgG (0.2 mg in complete Freund's adjuvant). At day 6.5 after immunization, mice received a single i.v. injection of sheep anti-mouse GBM (1 mg in 200 microl PBS). Mice were sacrificed at day 1 and 10 after induction of the disease. All WT mice survived until day 10, whereas 1 eNOS-/- mouse died and 2 more became moribund, requiring sacrifice. At day 10, eNOS-/- mice had higher levels of blood urea nitrogen than WT mice (P < 0.02), although proteinuria was comparable. Immunofluorescence microscopy documented similar IgG deposition in both WT and eNOS-/- mice, but eNOS-/- mice had more extensive glomerular staining for fibrin at day 10 (P < 0.007). At day 10, light microscopy demonstrated that eNOS-/- mice had more severe glomerular thrombosis (P < 0.003) and influx of neutrophils (P < 0. 006), but similar degrees of overall glomerular endocapillary hypercellularity and crescent formation. In conclusion, accelerated anti-GBM glomerulonephritis is severely aggravated in eNOS-/- mice, especially with respect to glomerular capillary thrombosis and neutrophil infiltration. These results indicate that NO radicals generated by eNOS play a protective role during renal inflammation.