Decreases in anti-double-stranded DNA levels are associated with concurrent flares in patients with systemic lupus erythematosus

OBJECTIVE: To determine the degree to which changes in anti-double-stranded DNA (anti-dsDNA), as determined by Crithidia and enzyme-linked immunosorbent assays (ELISAs), precede or coincide with changes in systemic lupus erythematosus (SLE) activity, as measured by 5 clinical indices, the physician's global assessment (PGA), modified SLE Disease Activity Index (M-SLEDAI), modified Lupus Activity Index (M-LAI), Systemic Lupus Activity Measure (SLAM), and the modified British Isles Lupus Assessment Group (M-BILAG). METHODS: Disease activity and anti-dsDNA were measured monthly in 53 SLE patients who were followed up for 1 year. Lupus flare was defined as an increase in PGA of > or = 1.0, M-SLEDAI > or = 3, M-LAI > or = 0.1, SLAM > or = 3, and M-BILAG > or = 4 within a 1-month period. Flare rates were calculated for groups, which were defined by "previous" (1 month prior to the flare) or "concurrent" (at the time of the flare) changes in anti-dsDNA. Logistic regression models were used to determine the significance of the association between recent changes in anti-dsDNA and flare, controlling for the prednisone dosage. RESULTS: Flares occurred at 12% of visits, based on the PGA measure of disease activity. Using the other indices, flare rates were 19% (M-SLEDAI), 25% (M-LAI), 13% (SLAM), and 12% (M-BILAG). A concurrent decrease in anti-dsDNA (ELISA) was associated with significantly higher flare rates based on PGA (18 of 84, 21%; P = 0.0014), M-SLEDAI (27 of 89, 30%; P = 0.0019), M-LAI (37 of 89, 42%; P = 0.0001), and M-BILAG (19 of 89, 21%; P = 0.0264) scores. Flare rates were also significantly higher after a previous increase in anti-dsDNA (ELISA) based on M-SLEDAI (26 of 93, 30%; P = 0.0022) and M-LAI (34 of 93, 37%; P = 0.0117) scores. Flare rates tended to be lowest when there was a concurrent increase in anti-dsDNA (ELISA). Analysis of specific organ systems showed that a concurrent decrease in anti-dsDNA (ELISA) was significantly associated with increases in renal disease activity. Similar results were obtained using the Crithidia assay. CONCLUSION: A previous increase in anti-dsDNA levels occurred before SLE flares, as measured by the M-SLEDAI and M-LAI only. However, during lupus flares, including the subset of renal flares, anti-dsDNA levels frequently decreased. We hypothesize that this decrease in anti-dsDNA represents deposition in tissue at the time of flare.     

Anti-nucleosome antibodies in patients with systemic lupus erythematosus of recent onset. Potential utility as a diagnostic tool and disease activity marker

OBJECTIVE: To compare the utility of anti-chromatin antibodies for the diagnosis of systemic lupus erythematosus (SLE) and as markers of disease activity. METHODS: We included 73 consecutive patients (62 female) with SLE (four or more ACR criteria) of recent onset (<1 yr since diagnosis). As control groups we included 130 healthy blood donors and 261 patients with 11 systemic autoimmune diseases (SAD). Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). A venous blood sample was drawn to measure three anti-chromatin antibodies [anti-nucleosome (anti-NCS), anti-double-stranded DNA (anti-dsDNA) and anti-histones (anti-HST)] by enzyme-linked immunosorbent assay. RESULTS: The prevalence of anti-chromatin antibodies in SLE patients and healthy controls was 100 and 3% respectively for anti-NCS, 63 and 5% for anti-dsDNA, and 15 and 3% for anti-HST. Anti-NCS had a sensitivity of 100% and specificity of 97% for SLE diagnosis. When SLE and SAD patients were compared [excluding mixed connective tissue disease (MCTD)], the sensitivity of anti-NCS, anti-dsDNA and anti-HST antibodies for SLE diagnosis was 93, 71 and 40% respectively and the specificity was 97, 98 and 98%. Anti-chromatin antibodies were not useful in differentiating between SLE and MCTD patients. Anti-NCS antibodies showed the highest correlation with disease activity (r = 0.45, P < 0.0001), especially in patients negative for anti-dsDNA antibodies (r = 0.58, P = 0.001). Anti-NCS antibodies also showed strong association with renal damage (odds ratio 4.1, 95% confidence interval 1.2-13.6, P = 0.01). CONCLUSION: Anti-NCS antibodies could be a useful tool in the diagnosis and assessment of disease activity in SLE patients, especially in patients who are negative for anti-dsDNA antibodies.     

The effect of moderate-dose corticosteroids in preventing severe flares in patients with serologically active, but clinically stable, systemic lupus erythematosus: findings of a prospective, randomized, double-blind, placebo-controlled trial

OBJECTIVE: Serial measurements of anti-double-stranded DNA (anti-dsDNA) and complement are routine in the management of systemic lupus erythematosus (SLE), but their utility as biomarkers in preemptive treatment to prevent flares remains a subject of controversy. We hypothesized that concomitant elevation of anti-dsDNA and C3a can predict SLE activity in patients with stable or inactive disease and that short-term treatment with corticosteroids can avert flares. METHODS: In this prospective, randomized, double-blind, placebo-controlled trial, 154 patients were evaluated monthly for up to 18 months, with measurements of C3a, C3, C4, CH50, and anti-dsDNA levels. Patients who remained clinically stable but showed serologic evidence of an SLE flare (elevation of both the anti-dsDNA level by 25% and the C3a level by 50% over the previous 1-2 monthly visits) were randomized to receive either prednisone or placebo therapy at a dosage of 30 mg/day for 2 weeks, 20 mg/day for 1 week, and 10 mg/day for 1 week. RESULTS: Forty-one patients (21 randomized to prednisone and 20 randomized to placebo) experienced a serologic flare. Analysis of severe flares occurring 40 mg/day and/or the addition of an immunosuppressive agent. Furthermore, improvement in scores on the Systemic Lupus Erythematosus Disease Activity Index, decreased levels of anti-dsDNA antibodies, and increased levels of C4 occurred 1 month after initiation of prednisone treatment. CONCLUSION: These preliminary data support our hypothesis that in a subset of clinically stable SLE patients with a combination of elevated C3a and anti-dsDNA levels, short-term corticosteroid therapy may avert a severe flare.     

Anti-C1q antibodies in pregnant patients with systemic lupus erythematosus

OBJECTIVE: To study anti-C1q antibodies in pregnant patients with systemic lupus erythematosus (SLE) and to evaluate their prognostic significance for the occurrence of disease flares or pregnancy complications. METHODS: Twenty-one pregnancies in 19 SLE patients prospectively followed were analyzed. Disease activity was evaluated on the basis of the physician's intention to treat and a modified version of the ECLAM index. Anti-C1q and anti-dsDNA antibodies were detected in the sera by an ELISA assay. Antinuclear antibodies, anti-ENA antibodies, anticardiolipin antibodies and lupus anticoagulant were also performed. RESULTS: In all the patients the disease was inactive at the beginning of the pregnancy. Four flares of disease activity were observed in 4 pregnancies (19%) and obstetric complications were encountered in 7 pregnancies (43%). Anti-C1q antibodies were positive in 4 (19%) pregnancies and anti-dsDNA antibodies in 8 (38%). The presence of anti-phospholipid antibodies at the first assessment was correlated with the occurrence of obstetric complications (p<0.05). The presence of anti-C1q and anti-dsDNA antibodies at the first assessment had no prognostic significance for the occurrence of flares or obstetric complications during the course of pregnancy. Although the small number of patients studied did not allow for statistically significant analysis, flares appeared to be more likely to occur in patients presenting with anti-dsDNA or anti-C1q antibodies during pregnancy compared to patients with no changes in these antibody titers (43% vs 8% respectively). CONCLUSIONS: The presence of anti-C1q and anti-dsDNA antibodies does not seem to be prognostic for the occurrence of flares during pregnancy. Further studies are warranted to explore this possibility.     

An analysis of clinical disease activity and nephritis-associated serum autoantibody profiles in patients with systemic lupus erythematosus: a cross-sectional study.

OBJECTIVE: To establish the correlation between lupus nephritis-associated autoantibody levels and the presence/activity of lupus nephritis and global disease activity using cross-sectional data in patients with systemic lupus erythematosus (SLE). METHODS: Disease activity was assessed using the British Isles Lupus Assessment Group (BILAG) index. Antibody levels against single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), histones, nucleosomes and heparan sulphate (HS) were analysed by ELISA in SLE patients with (n=11) and without (n=22) nephritis and in normal controls (n=21). Antibody subclasses were also analysed. RESULTS: Higher levels of anti-dsDNA and anti-HS antibodies were found in patients with lupus nephritis, the level of anti-HS antibodies correlating with the BILAG renal score. Predominant subclasses were IgG1 and IgG3 for dsDNA antibodies, IgG2 for anti-nucleosome antibodies, and IgG2 and IgG3 for anti-HS antibodies. CONCLUSION: Correlation was demonstrated between antibodies to dsDNA, ssDNA, histones, nucleosomes and HS. There is a strong correlation between the level of anti-HS antibodies and disease activity in patients with lupus nephritis as measured by BILAG.     

Abetimus sodium for renal flare in systemic lupus erythematosus: results of a randomized, controlled phase III trial

OBJECTIVE: To investigate whether treatment with abetimus delays renal flare in patients with lupus nephritis. Secondary objectives included evaluation of the effect of abetimus on C3 levels, anti-double-stranded DNA (anti-dsDNA) antibody levels, use of high-dose corticosteroids and/or cyclophosphamide, and major systemic lupus erythematosus (SLE) flare. METHODS: We conducted a randomized, placebo-controlled study of treatment with abetimus at 100 mg/week for up to 22 months in SLE patients. Three hundred seventeen patients with a history of renal flare and anti-dsDNA levels >15 IU/ml were randomized to a treatment group (158 abetimus, 159 placebo); 298 (94%) were enrolled in the intent-to-treat (ITT) population (145 abetimus, 153 placebo), based on the presence of high-affinity antibodies for the oligonucleotide epitope of abetimus at baseline screening. RESULTS: Abetimus did not significantly prolong time to renal flare, time to initiation of high-dose corticosteroid and/or cyclophosphamide treatment, or time to major SLE flare. However, there were 25% fewer renal flares in the abetimus group compared with the placebo group (17 of 145 abetimus-treated patients [12%] versus 24 of 153 placebo-treated patients [16%]). Abetimus treatment decreased anti-dsDNA antibody levels (P < 0.0001), and reductions in anti-dsDNA levels were associated with increases in C3 levels (P < 0.0001). More patients in the abetimus group experienced > or =50% reductions in proteinuria at 1 year, compared with the placebo group (nominal P = 0.047). Trends toward reduced rates of renal flare and major SLE flare were noted in patients treated with abetimus who had impaired renal function at baseline. Treatment with abetimus for up to 22 months was well tolerated. CONCLUSION: Abetimus at 100 mg/week significantly reduced anti-dsDNA antibody levels but did not significantly prolong time to renal flare when compared with placebo. Multiple positive trends in renal end points were observed in the abetimus treatment group.     

Restricted specificity of anti-ribosomal P antibodies to SLE patients in Israel

OBJECTIVE: Anti-ribosomal P antibodies (aRib-P Ab) are highly specific for systemic lupus erythematosus (SLE), but their correlatation with disease activity and manifestations including renal, hepatic and central nervous system (CNS) involvement is still controversial. The aim of our study was to evaluate the prevalence of aRib-P Ab and their correlation with clinical manifestations and anti-dsDNA antibodies in SLE patients from Israel. METHODS: Elevated titers of aRib-P Ab utilizing the ELISA method were analyzed in 141 sera samples from 44 SLE patients, 20 Familial Mediterranean Fever (FMF) patients, 22 primary antiphospholipid syndrome (PAPS) patients, 12 patients with infections, and 43 healthy individuals. The SLEDAI score was utilized for assessing SLE disease activity. RESULTS: Elevated titers of aRib-P Ab were present in 11% of SLE patients (n = 6). The mean SLEDAI was 7 (range: 3-10). No statistically significant association was observed between the presence of aRib-P Ab and disease manifestations present in the SLEDAI. The 6 SLE patients had renal disease (n = 1), leucopenia (n = 1), rash (n = 3), and CNS involvement manifested as psychosis (n = 1) or depression (n = 1). Elevated titers of anti-dsDNA antibodies were found in 50% of patients with elevated titers of aRib- P Ab. Patients with PAPS, FMF, infections or healthy controls did not harbor elevated titers of aRib-P Ab. CONCLUSION: Elevated titers of aRib-P Ab were restricted to SLE patients. We confirm previously reported associations of aRib-P Ab reactivity with disease activity and elevated anti-dsDNA Ab titers. No significant correlation with a specific manifestation described on the SLEDAI score was established in this small cohort of patients.     

Prior anti-dsDNA antibody status does not predict later disease manifestations in systemic lupus erythematosus

OBJECTIVES: To determine if the past presence of anti-double-strand (ds)DNA antibody (Ab) will predict subsequent disease activity in patients with systemic lupus erythematosus (SLE). METHODS: A longitudinal study of clinical and serological disease manifestations registered during 2,412 patient months of follow-up in a well-defined lupus cohort. Organ-specific disease manifestations, the modified SLE disease activity index (M-SLEDAI) score, disease flares (M-SLEDAI increase > or =3) and predictive value of anti-dsDNA Ab testing [by enzyme-linked immunoabsorbent assay (ELISA) and Crithidia luciliae immunofluorescence (CLIFT) assays] were related to past anti-dsDNA Ab status. RESULTS: Anti-dsDNA Ab was previously demonstrated in 54 (57%) patients (group 1), while they were not earlier detected in 40 (43%) patients (group 2). The number of patients experiencing flares (46 vs 25%, p<0.01), the total number of flares (75 vs 17, p<0,001) as well as overall (60 vs 24 per 100 patient years, p<0,001) and organ-specific flare rate were higher in group 1. After adjustment for control frequency, group 1 remained at a higher risk for renal flares [odds ratio (OR) 2.4; confidence interval (CI) 1.5-4.1], and group 2 was at a higher risk for skin flares (OR 0.7; CI 0.5-0.8). While anti-dsDNA Ab testing overall was performed slightly more often in group 1 (OR 1.45; CI 1.0-4.6), anti-dsDNA Ab testing during flares was similar in both groups. CONCLUSION: The past presence of anti-dsDNA Ab identified patients with an increased risk of subsequent renal flares. However, as a new onset of anti-dsDNA Abs occurred late in the disease course, prior anti-dsDNA status was not adequate to predict disease flares.     

Decreases in anti–double‐stranded DNA levels are associated with concurrent flares in patients with systemic lupus erythematosus

Objective

To determine the degree to which changes in anti–double‐stranded DNA (anti‐dsDNA), as determined by Crithidia and enzyme‐linked immunosorbent assays (ELISAs), precede or coincide with changes in systemic lupus erythematosus (SLE) activity, as measured by 5 clinical indices, the physician's global assessment (PGA), modified SLE Disease Activity Index (M‐SLEDAI), modified Lupus Activity Index (M‐LAI), Systemic Lupus Activity Measure (SLAM), and the modified British Isles Lupus Assessment Group (M‐BILAG).

Methods

Disease activity and anti‐dsDNA were measured monthly in 53 SLE patients who were followed up for 1 year. Lupus flare was defined as an increase in PGA of ≥1.0, M‐SLEDAI ≥3, M‐LAI ≥0.1, SLAM ≥3, and M‐BILAG ≥4 within a 1‐month period. Flare rates were calculated for groups, which were defined by “previous” (1 month prior to the flare) or “concurrent” (at the time of the flare) changes in anti‐dsDNA. Logistic regression models were used to determine the significance of the association between recent changes in anti‐dsDNA and flare, controlling for the prednisone dosage.

Results

Flares occurred at 12% of visits, based on the PGA measure of disease activity. Using the other indices, flare rates were 19% (M‐SLEDAI), 25% (M‐LAI), 13% (SLAM), and 12% (M‐BILAG). A concurrent decrease in anti‐dsDNA (ELISA) was associated with significantly higher flare rates based on PGA (18 of 84, 21%; P = 0.0014), M‐SLEDAI (27 of 89, 30%; P = 0.0019), M‐LAI (37 of 89, 42%; P = 0.0001), and M‐BILAG (19 of 89, 21%; P = 0.0264) scores. Flare rates were also significantly higher after a previous increase in anti‐dsDNA (ELISA) based on M‐SLEDAI (26 of 93, 30%; P = 0.0022) and M‐LAI (34 of 93, 37%; P = 0.0117) scores. Flare rates tended to be lowest when there was a concurrent increase in anti‐dsDNA (ELISA). Analysis of specific organ systems showed that a concurrent decrease in anti‐dsDNA (ELISA) was significantly associated with increases in renal disease activity. Similar results were obtained using the Crithidia assay.

Conclusion

A previous increase in anti‐dsDNA levels occurred before SLE flares, as measured by the M‐SLEDAI and M‐LAI only. However, during lupus flares, including the subset of renal flares, anti‐dsDNA levels frequently decreased. We hypothesize that this decrease in anti‐dsDNA represents deposition in tissue at the time of flare.

     

Relationship between anti-double-stranded DNA antibodies and exacerbation of renal disease in patients with systemic lupus erythematosus

OBJECTIVE: To examine the relationship between changes in anti-double-stranded DNA (anti-dsDNA) antibody levels and the risk of renal flare in patients with systemic lupus erythematosus (SLE), using data from 2 randomized, controlled trials. METHODS: Analyses were based on 487 patients with SLE and a history of lupus nephritis who had an anti-dsDNA antibody titer >/=15 IU/ml at baseline, as measured by Farr assay. Results are presented for the combined population of patients, the placebo arms, and the drug treatment arms in which a dsDNA-based bioconjugate (abetimus sodium; LJP 394) was used. RESULTS: Changes in anti-dsDNA antibody levels were inversely correlated with changes in the C3 level (P < 0.0001 in both trials). Cox proportional hazards regression models showed that changes in anti-dsDNA antibody levels correlated with the risk of renal flare. The models predicted that a point estimate of a 50% reduction in anti-dsDNA antibody levels is associated with a 52% reduction (95% confidence interval [95% CI] 26-68%, nominal P = 0.0007) and a 53% reduction (95% CI 33-69%, nominal P < 0.0001) in the risk of renal flare in the 2 trials, respectively. In the 2 trials, the incidence of renal flare was lower in patients with sustained reductions in anti-dsDNA antibodies (3.0% and 4.1%, respectively) than in patients with stable or increasing antibody levels (21.3% and 20.3%, respectively). CONCLUSION: Changes in anti-dsDNA antibody levels were directly correlated with the risk of renal flare and inversely correlated with changes in the C3 level. Reducing anti-dsDNA antibody levels may represent a therapeutic objective in SLE patients with lupus nephritis, because it is associated with a reduced risk of renal flare.     

THE OCCURRENCE, NATURE AND DISTRIBUTION OF FLARES IN A COHORT OF PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: A RHEUMATOLOGICAL VIEW

This study examines the occurrence, nature and distributionof disease flares in systemic lupus erythematosus (SLE) accordingto organ involvement. One-hundred-and-fourteen patients wereseen in the Lupus Clinic of the Bloomsbury Rheumatology Unitover a 3-yr period. At each visit a data sheet was completedto assess their disease activity in eight separate organs/systemsaccording to the British Isles Lupus Assessment Group (BILAG)activity index. This information was entered into a computerand a score for each organ system was obtained. The record ofeach individual patient was examined to identify flares in theindividual organs; 458 flares occurred in 107 patients. Themajority of patients (69%) experienced more than one flare duringthe study period. Fifty-four per cent of patients had flaresin more than one system simultaneously, but the majority (70%)of flares involved only one system. The most severe organ involvement(A score)was most commonly observed in the musculoskeletal system,whereas severe renal disease occurred only three times. Theseresults indicate that although SLE is a multisystem disease,the flares that occur tend to be confined to one system at atime. Further, these results demonstrate that in our rheumatologypractice the most common ‘A’ flare observedwas severepolyarthritis (A score in musculoskeletal). KEY WORDS: Systemic lupus erythematosus, Flares, BILAG, Arthritis     

Prevalence and clinico-serological correlations of anti-alpha-enolase, anti-C1q, and anti-dsDNA antibodies in patients with systemic lupus erythematosus

OBJECTIVE: To evaluate the prevalence and clinico-serological correlations of anti-enolase, anti-C1q, and anti-dsDNA antibodies in patients with systemic lupus erythematosus (SLE). METHODS: Sixty-eight sera randomly obtained from SLE patients were examined. Anti-alpha-enolase antibodies were detected by immunoblot on recombinant protein; anti-C1q and anti-dsDNA antibodies were detected using an ELISA. RESULTS: Anti-alpha-enolase, anti-C1q, and anti-dsDNA antibodies were positive in 21%, 62%, and 63% of patients, respectively. A correlation was found between anti-dsDNA and anti-C1q antibodies, while anti-enolase antibodies did not correlate with the other 2 specificities. Anti-alpha-enolase antibodies were not correlated with any of the clinical and serological variables examined. Anti-C1q antibodies were correlated with ECLAM score, leukopenia, complement levels, and active renal involvement. Anti-dsDNA antibodies correlated with arthritis, leukopenia, complement levels, and the presence of renal involvement, independent of activity. In patients with active renal disease anti-dsDNA antibodies were correlated with a poor renal outcome, occurring after a mean period of 24 months. CONCLUSION: These data suggest the association of anti-C1q antibodies with disease flares and active renal disease in SLE. The observed association of anti-dsDNA antibodies and renal disease was expected. Further analysis is required to fully assess the clinical significance of anti-a-enolase antibodies.     

Assessment of flares in lupus patients enrolled in a phase II/III study of rituximab (EXPLORER)

The EXPLORER study was designed to assess the response to rituximab versus placebo in patients with moderate to severe extrarenal systemic lupus erythematosus (SLE) receiving background immunosuppression. The definition of response required reduced clinical activity without subsequent flares over 52 weeks, and the study did not meet its efficacy endpoint. The current exploratory analysis assessed flare rates in patients who achieved initial low disease activity response (British Isles Lupus Assessment Group [BILAG] C or better in all organs) during the study. Exploratory reanalysis of data from the EXPLORER trial was conducted, considering alternative definitions for flare. No difference was found between rituximab and placebo in preventing or delaying moderate to severe flares. However, when severe (BILAG A) flares alone were examined, rituximab reduced the risk of a subsequent first A flare (hazard ratio?=?0.61; p?=?0.052) and lowered mean?±?SD annualized A flare rates (0.86?±?1.47 vs. 1.41?±?2.14; p?=?0.038). Eighty-four (49.7%) rituximab-treated patients achieved low disease activity without subsequent A flares versus 31 (35.2%) placebo-treated patients (p?=?0.027). Prednisone rescue for A flares was similar in rituximab- (24%) and placebo-treated (14%) patients (p?=?0.204). This post hoc analysis evaluates the hypothesis that assessment of BILAG A flares may distinguish potential treatment effects with greater sensitivity than assessment of BILAG B flares.     

Anti-dsDNA antibody avidity determination by a simple reliable ELISA method for SLE diagnosis and monitoring

High avidity anti-dsDNA antibodies are more specific for SLE diagnosis, and more closely associated with renal involvement than intermediate or low-affinity anti-dsDNA antibodies. ELISA methods are largely used to detect anti-dsDNA, but their high sensitivity is inversely related to specificity because they also detect low avidity antibodies. We developed an ELISA assay based on the law of mass action and the competitive binding of dsDNA in solution and coated to microwells with anti-dsDNA antibodies. A simplified Scatchard plot analysis system was used to measure anti-dsDNA antibody avidity which was expressed as apparent affinity constant (Kaa), and quantified in liters per unit (I/U). We prospectively studied 101 consecutive SLE patients, who were followed for 3 years; three serum samples were sequentially collected from each patient during follow-up for determination of IgG anti-dsDNA antibody concentration, and anti-dsDNA avidity. SLE disease activity was estimated using the European Consensus Lupus Activity Measure (ECLAM) index. Sera from 100 healthy subjects and 133 patients with other connective tissue diseases or infectious diseases were also assayed as controls. The mean Kaa in SLE patients was 65.2 +/- 47.3 l/U, with no variations over time. Anti-dsDNA-positive SLE patients had higher Kaa values (79.1 +/- 46.8) than anti-dsDNA negative patients (27.2 +/- 20.1; P < 0.001). No correlation emerged between anti-dsDNA avidity and the ECLAM activity index score. Avidity was significantly higher in patients with renal involvement vs patients without this complication (78.2 +/- 50 vs 59.9 +/- 45.6 l/U; P = 0.0013). This simple ELISA method could be very useful in the diagnostic phase to differentiate high avidity anti-dsDNA autoantibodies that are characteristically found in SLE patients from low avidity antibodies that can also be found in other inflammatory diseases. Moreover, our data confirm the predictive value of high avidity anti-dsDNA antibodies for the development of lupus nephritis.     

Association of alpha-actinin-binding anti-double-stranded DNA antibodies with lupus nephritis

OBJECTIVE: Anti-double-stranded DNA (anti-dsDNA) antibodies may contribute to the pathogenesis of glomerulonephritis (GN) by cross-reacting with alpha-actinin in murine models and in some patients with systemic lupus erythematosus (SLE). We therefore sought to determine possible disease associations with serologic and clinical features and to characterize this new autoantibody specificity. METHODS: One hundred patients with SLE were recruited into this multicenter study, as well as 100 rheumatic disease controls and 2,100 healthy blood donors. Clinical disease was evaluated by the SLE Disease Activity Index (SLEDAI; excluding the anti-DNA component). Anti-dsDNA antibodies were detected by conventional enzyme-linked immunosorbent assay (ELISA) and by a commercial enzyme immunoassay (EIA). Anti-alpha-actinin antibodies were detected by ELISA, and their specificity was confirmed by Western blotting and by indirect immunofluorescence using rat kidney sections and mesangial cells as substrates. Highly positive sera were selected for absorption experiments and were affinity-purified for cross-reactivity studies and measurement of antibody avidity. RESULTS: Sera from 62 of the SLE patients had anti-dsDNA antibodies; 21 of these sera also had anti-alpha-actinin antibodies, as compared with 1 of the 38 sera without anti-dsDNA antibodies. Of the 22 patients with anti-alpha-actinin antibodies, 10 had GN, as compared with 14 of the 78 without anti-alpha-actinin antibodies (P < 0.01). In patients with GN, anti-alpha-actinin, but not anti-dsDNA, antibodies correlated with the SLEDAI score (minus the anti-DNA component) and with treatment. The fraction of serum anti-dsDNA antibodies that cross-reacted with alpha-actinin exhibited high avidity for dsDNA, as determined using a commercial EIA for high-avidity anti-dsDNA antibodies and an in-house conventional ELISA. CONCLUSION: The alpha-actinin-binding antibodies are significantly associated with GN in SLE. Whether such autoantibodies may anticipate the development of this complication of SLE remains to be verified.     

Investigation of the prevalence and clinical associations of antibodies to human fibronectin in systemic lupus erythematosus.

OBJECTIVES--To assess the prevalence of antibodies to human fibronectin (anti-Fn) in sera of patients with certain connective tissue diseases and to determine their association with disease activity and the pattern of organ involvement in patients with systemic lupus erythematosus (SLE). METHODS--A capture enzyme linked immunosorbent assay (ELISA) was developed to quantify anti-Fn antibodies in serum samples from 65 patients with well characterised SLE, 50 with rheumatoid arthritis (RA), 15 with Behçet's disease (BD), 15 with systemic vasculitis and 36 healthy subjects. An anti-Fn antibody titre greater than mean + 3SD of the healthy control log values after back transformation to the normal scale was considered positive. Disease activity in SLE patients was scored using the British Isles Lupus Assessment Group (BILAG) Index. Erythrocyte sedimentation rate (ESR), concentrations of anti-dsDNA antibody, soluble interleukin-2 receptors (sIL-2R), C3, C4, C3 degradation products (C3dg) and immunoglobulin, and antinuclear antibody (ANA) titres were measured in blood samples from SLE patients; neopterin concentration was measured in corresponding urine samples. RESULTS--Anti-Fn antibodies were found in 22 of 65 SLE patients (33.8%), seven of 50 with RA (14%), one of 15 with BD (6.6%) and none of the 15 subjects with vasculitis. Thirty SLE patients had active disease and 35 had inactive disease; their median anti-Fn concentrations were 117 u/ml (range 47-450) and 68 u/ml (range 17-334), respectively (p = 0.0001). The presence of anti-Fn did not correlate with immunoglobulin concentrations or ANA titres in these sera. No significant difference was found between SLE patients with disease activity in one major organ system compared with multiple organ involvement, as defined by BILAG (p = 0.19). However, patients with musculoskeletal manifestations had consistently greater anti-Fn concentrations compared with patients with other clinical manifestations. There were significant correlations between amounts of anti-Fn in SLE sera and ESR (rs = 0.25, p = 0.045), sIL-2R (rs = 0.28, p = 0.024) and urine neopterin (rs = 0.3, p = 0.016) but not with serum anti-dsDNA antibody titres, plasma C3, C3dg or C4. However multiple regression analysis showed a low significant correlation only with sIL-2R and BILAG score (p = 0.047 and 0.042, respectively). CONCLUSION--Anti-Fn antibodies were detected in 34% of SLE patients and in small proportions of RA and BD patients. An association between serum anti-Fn and disease activity in SLE has been identified and most SLE patients with musculoskeletal involvement had increased anti-Fn antibody concentrations.     

Prolonged remission in systemic lupus erythematosus

OBJECTIVE: To determine the frequency of prolonged remission in systemic lupus erythematosus (SLE) using strict criteria for remission and to define disease characteristics and prognosis of patients achieving this state. To also determine the frequency of remission utilizing less restrictive definitions, such as allowing shorter period of disease quiescence, persistence of serological activity, or treatment in the absence of clinical disease. METHODS: Patients registered in the Lupus Clinic database between 1970 and 1997 with visits no more than 18 months apart were identified. Prolonged remission was defined as a 5-year consecutive period of no disease activity (SLE disease activity index, SLEDAI = 0) and without treatment (corticosteroids, antimalarials, or immunosuppressants). Prolonged serologically active, clinically quiescent (SACQ) was defined as active serology (elevated anti-dsDNA by Farr assay or hypocomplementemia) but no clinical activity on SLEDAI and no treatment. RESULTS: Seven hundred and three patients fulfilled inclusion criteria. Of the 703 patients 46 (6.5%) achieved complete remission for at least 1 year, whereas only 12 patients (1.7%) had prolonged complete remission of at least 5 years on no treatment. Although the frequency of disease manifestations was similar to the patients not in remission, the 5-year remission group was distinguished by lower overall disease activity as measured by adjusted mean SLEDAI, lower prevalence of anti-DNA antibodies, and lower use of steroids and antimalarials. CONCLUSION: Prolonged complete remission in lupus is rare. Therefore with current therapies continued vigilance for disease recurrence is necessary.     

Antinucleosome antibodies as a potential biomarker for the evaluation of renal pathological activity in patients with proliferative lupus nephritis

The objective of this study is to evaluate the correlation between antinucleosome antibodies and renal pathological activity in patients with proliferative lupus nephritis (LN). We evaluated 36 patients with proliferative LN, 14 non-renal lupus patients and 10 healthy volunteers. Lupus activity was assessed using the British Isles Lupus Assessment Group 2004 (BILAG 2004) index, serum anti-double stranded DNA (anti-dsDNA) levels, serum complement levels and daily urinary protein levels. All 36 lupus nephritis patients received renal biopsy. Antinucleosome antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Our results showed that levels of serum antinucleosome antibodies were significantly higher in LN patients (median 90.35 units/ml, interquartile range [IQR] 37.38-135.23) than in non-renal SLE patients (median 5.45 units/ml, IQR 2.6-28.93, p <0.05) and in healthy volunteers (median 3.35 units/ml, IQR 2.95-5.23, p <0.001). Serum levels of antinucleosome antibodies were positively correlated with BILAG index (Spearman's r = 0.645, p <0.001) and serum anti-dsDNA antibody levels (r(s) = 0.644, p <0.01), while serum levels of antinucleosome antibodies were negatively correlated with serum levels of C3 (r(s) = -0.400, p <0.01) and C4 (r(s) = -0.300, p <0.05). Serum levels of antinucleosome antibodies were positively correlated with the histological activity index of LN (r(s) = 0.368, p <0.05). However, there was no significant correlation between serum levels of antinucleosome antibodies and the histological chronicity index. In conclusion, the serum level of antinucleosome antibodies is a potential biomarker for early recognition of renal involvement and evaluation of disease activity in SLE. Our preliminary results suggested that serum levels of antinucleosome antibodies might be a potential biomarker in evaluating pathological activity of LN.     

Antinuclear antibodies following infliximab treatment in patients with rheumatoid arthritis or spondylarthropathy

OBJECTIVE: To investigate the effect of infliximab treatment on antinuclear antibodies (ANAs), anti-double-stranded DNA (anti-dsDNA), antinucleosome, antihistone, and anti-extractable nuclear antigen (anti-ENA) antibodies in rheumatoid arthritis (RA) and spondylarthropathy (SpA) patients. METHODS: Sera from 62 RA and 35 SpA patients treated with infliximab were tested at baseline and week 30 (RA group) or week 34 (SpA group). ANAs were tested by indirect immunofluorescence (IIF) on HEp-2 cells. Anti-dsDNA antibodies were detected by IIF on Crithidia luciliae and by enzyme-linked immunosorbent assay (ELISA) and were further isotyped with gamma, mu, and alpha chain-specific conjugates at various time points. Antinucleosome antibodies were tested by ELISA. Antihistone and anti-ENA antibodies were detected by line immunoassay. RESULTS: Initially, 32 of 62 RA patients and 6 of 35 SpA patients tested positive for ANAs. After infliximab treatment, these numbers shifted to 51 of 62 (P < 0.001) and 31 of 35 (P < 0.001), respectively. At baseline, none of the RA or SpA patients had anti-dsDNA antibodies. After infliximab treatment, 7 RA patients (P = 0.016) and 6 SpA patients (P = 0.031) became positive for anti-dsDNA antibodies. All 7 anti-dsDNA-positive RA patients had IgM and IgA anti-dsDNA antibodies. Three of the 6 anti-dsDNA-positive SpA patients had IgM and IgA anti-dsDNA antibodies, and 2 had IgM anti-dsDNA antibodies alone. In both diseases, the IgM anti-dsDNA antibodies appeared before the IgA anti-dsDNA antibodies. During the observation period, no IgG anti-dsDNA antibodies or lupus symptoms were observed. The development of antinucleosome, antihistone, or anti-ENA antibodies following infliximab treatment was observed in some patients, but the numbers were not statistically significant. CONCLUSION: Infliximab treatment may induce ANAs, and especially IgM and IgA anti-dsDNA antibodies, in RA and SpA patients. However, no anti-dsDNA IgG antibodies or lupus symptoms were observed during the period of observation in this study, and the development of antinucleosome, antihistone, or anti-ENA antibodies was not statistically significant. These observations do not exclude potential induction of clinically significant lupus in the long term, and further followup is therefore mandatory.     

三种自身抗体联合检测对狼疮疾病活动和狼疮肾炎的价值

目的探讨联合检测抗C1q抗体、抗核小体抗体(AnuA)和抗dsDNA抗体对狼疮活动和狼疮肾炎(LN)的价值。方法 90例系统性红斑狼疮(SLE)分为疾病活动和疾病稳定组、LN和非LN组, 酶联免疫吸附试验(ELISA)检测血清抗C1q抗体和AnuA水平,间接免疫荧光法比较三抗体单个和联合对疾病活动和LN的价值。结果抗C1q抗体、AnuA和抗dsDNA抗体阳性对疾病活动的敏感性分别为 71．4％、75．0％和66．1％,特异性分别为75．5％、70．6％和88．2％;抗dsDNA抗体阴性患者分别有36．7％抗 C1q抗体阳性和26．5％AnuA阳性。疾病活动组三抗体阳性率和抗体水平显著高于疾病稳定组;三抗体与 SLE疾病活动指数(SLEDAI)、血沉(ESR)、IgG、球蛋白水平显著正相关,与C3、C4及白蛋白水平显著负相关。LN组三抗体水平显著高于非LN组。结论三抗体都是狼疮疾病活动的指标,都与LN有关,联合检测可以提高疾病活动检出率。