To evaluate the predictive power of changes in levels of antibodies to double-stranded DNA (antidsDNA) as a predictor of disease exacerbations in systemic lupus erythematosus (SLE), we performed a prospective study on 72 unselected patients with SLE (mean duration of study 18.5 months, range 6-35 months). Patients were seen at least once every 3 months, and disease activity was scored according to a specific protocol. Plasma samples were obtained at least once every month and were assessed for anti-dsDNA antibody (by the Crifhidiu luciliue assay, an enzymelinked immunosorbent assay [ELISA], and the Farr assay) and for complement components C3 and C4. Twenty-seven of 33 disease exacerbations observed during the study period were accompanied by a positive test result for anti-dsDNA antibody (27 by the Farr assay, 19 by the C luciliae assay, and 23 by the ELISA). Twentyfour of these exacerbations were preceded by a significant increase in anti-dsDNA antibody levels (23 by the Farr assay, 12 by the C luciliae assay, and 17 by the ELISA). The first observance of a significant increase in anti-dsDNA antibody levels preceded the exacerbation by 8-10 weeks. Significant increases in anti-dsDNA antibody levels not followed by an exacerbation were observed in 5 cases by the Farr assay, in 7 cases by the C luciliue assay, and in 3 cases by the ELISA; however, in 3 cases, 2 cases, and 1 case, respectively, these increases were followed by an increase in disease activity that did not fulfill the criteria for an exacerbation. Serial measurement of anti-dsDNA antibody levels was more sensitive for predicting exacerbations than was measurement of C3 andor C4 levels (P < 0.03). Serial assessment of anti-dsDNA antibody levels, especially by the Farr assay, is a sensitive and reasonably specific method for predicting disease exacerbations in SLE.Systemic lupus erythematosus (SLE) is characterized by protean clinical manifestations and the occurrence of a variety of autoantibodies. Among these, anti-double-stranded DNA (anti-dsDNA) antibodies are highly specific for SLE and are detected at a high frequency (75-

Objective. Prediction of relapses inConclusion. Serial measurement of ANCA levels is valuable for the early prediction of relapses in patients with WG.

IntroductionHigh Mobility Group Box 1 (HMGB1) is a nuclear non-histone protein. HMGB1, which is secreted by inflammatory cells and passively released from apoptotic and necrotic cells, may act as a pro-inflammatory mediator. As apoptotic cells accumulate in systemic lupus erythematosus (SLE), HMGB1 levels might be increased in SLE. HMGB1 may also serve as an autoantigen, leading to the production of anti-HMGB1 antibodies. In this study we determined levels of HMGB1 and anti-HMGB1 in SLE patients in comparison to healthy controls (HC) and analysed their relation with disease activity.MethodsThe study population consisted of 70 SLE patients and 35 age- and sex-matched HC. Thirty-three SLE patients had quiescent disease, the other 37 patients were selected for having active disease. Nineteen of these had lupus nephritis. HMGB1 levels were measured with both Western blot and ELISA. Anti-HMGB1 levels were measured by ELISA. Clinical and serological parameters were assessed according to routine procedures.ResultsHMGB1 levels in SLE patients could be measured reliably by Western blotting only, and were significantly increased compared to HC. During active disease HMGB1 levels increased, in particular in patients with renal involvement. Serum HMGB1 levels correlated with SLEDAI, proteinuria, and anti-dsDNA levels, and showed a negative correlation with complement C3. Anti-HMGB1 levels were significantly increased in SLE patients compared to HC, and positively correlated with HMGB1 levels.ConclusionsLevels of HMGB1 in the sera of SLE patients, in particular in those with active renal disease, are increased. Serum HMGB1 levels are related to SLEDAI scores and proteinuria, as well as to levels of anti-HMGB1 antibodies. These findings suggest that besides HMGB1, HMGB1-anti-HMGB1 immune complexes play a role in the pathogenesis of SLE, in particular in patients with renal involvement.

Abstract. 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 Ϫ -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 ϩ neutrophils and an elevated level of mPR3 expression compared with healthy individuals (P ϭ 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 ϭ 0.021) and with an increased relapse rate (P ϭ 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.Wegener granulomatosis (WG) is a systemic disease characterized by necrotizing inflammation of the respiratory tract, vasculitis, and pauci-immune glomerulonephritis (1). WG is strongly associated with the presence of antineutrophil cytoplasm autoantibodies (ANCA) with specificity for proteinase 3 (PR3) (2-4). Although the role of these autoantibodies has not been fully established yet, there is increasing evidence that PR3-ANCA are involved in the pathogenesis of WG. Remarkably, relapses of WG are frequently preceded by a rise of PR3-ANCA (5,6).PR3 is a serine proteinase stored in azurophil granules of polymorphonuclear neutrophils (7,8). It has also been shown to localize in specific granules and secretory vesicles (9). In vitro, after priming with tumor necrosis factor-␣ (TNF␣) PR3 is translocated to the cell surface, where it becomes accessible for interaction with PR3-ANCA (10). Cross-linking of PR3 and Fc␥ receptors on the surface of primed neutrophils by PR3-ANCA induces neutrophil activation that results in the release of reactive oxygen species and proteolytic enzymes (11)(12)(13)(14). Moreover, ANCA-activated neutrophils have been shown to be cytotoxic against vascular endothelium (15).Recently, it has been found that in som...