血清抗C1q抗体与狼疮肾炎活动性及病理改变的相关性

目的 探讨血清抗C1q抗体与狼疮肾炎(LN)肾组织病理改变的相关性,以及对LN的活动性的评价.方法 用酶联免疫吸附法(ELISA)检测活动期LN患者60例和非LN患者60例血清中的抗C1q抗体,分析这一抗体与LN肾组织病理改变、活动指数及其他实验室参数的相关性.结果 LN患者血清抗C1q抗体水平(89±26)U/ml较非LN患者(57±23)U/ml高(P＜0.01);60例LN患者有同期肾活检病理资料,按世界卫生组织(WHO)分型,Ⅱ型12例,Ⅲ型14例,Ⅳ型18例,Ⅴ型16例.经方差分析显示,各病理类型问抗C1q抗体水平差异有统计学意义,其中以Ⅳ型LN的抗C1q抗体水平显著高于其他病理类型(P＜0.01);C1q在肾组织的沉积与血清抗C1q抗体水平相关;血清抗C1q抗体水平与肾脏病变的活动指数(AI)及尿蛋白含量呈正相关(P＜0.01),与补体C3、C4水平呈负相关(P＜0.01);抗双链DNA(dsDNA)抗体阳性的SLE患者,血清抗C1q抗体水平高于抗dsDNA抗体阴性者(P＜0.01).结论 血清抗C1q抗体水平在一定程度上反映LN肾脏的病理改变,并与肾脏病变活动指数有相关性,检测血清抗C1q抗体对评价LN病情及指导治疗有临床实用价值.     

抗核小体抗体与抗C1q抗体在狼疮肾炎血清的表达及其临床意义

目的探讨抗核小体抗体与抗C1q抗体在狼疮肾炎（lupus nephritis，LN）患者血清的表达及其临床意义。方法使用酶联免疫吸附试验（ELISA）对46例LN患者血清进行检测，并与31例无肾炎临床表现的SLE患者作对照。结果LN患者血清中抗核小体抗体与抗C1q抗体浓度及阳性率显著高于SLE对照组（P〈0．01）。抗双链DNA（dsDNA）抗体、抗Sm抗体、抗nRNP抗体、抗心磷脂（aCL）IgG抗体有较高的阳性率，与对照组相比差异有统计学意义（P〈0．05）。将抗核小体抗体、抗C1q抗体、抗dsDNA抗体、抗Sm抗体、抗nRNP抗体和aCLIgG抗体分别引入Logistic回归进行统计分析，结果显示入选的自变量包括抗核小体抗体、抗C1q抗体、抗dsDNA抗体（P〈0．05）。结论在LN患者中，存在着抗核小体抗体、抗C1q抗体的高表达。抗核小体抗体及抗C1q抗体在LN发病中起重要的作用。抗核小体抗体、抗C1q抗体、抗dsDNA抗体是反映SLE患者并发肾脏损害的重要指标，在LN诊断和判定其活动性方面有重要作用。     

Anti-dsDNA antibody subtypes and anti-C1q antibodies: toward a more reliable diagnosis and monitoring of systemic lupus erythematosus and lupus nephritis

The putative distinct diagnostic and pathogenic potential of aDNA-Ab subtypes, differing in their affinity or epitope specificity, was subject of several studies with controversial results. Comparing five assays, characterized by different reaction conditions and nature/source of dsDNA, we investigated the abovementioned problem in a retrospective study on 100 systemic lupus erythematosus (SLE) patients and 100 controls (other CTD, autoimmune hepatopathies). As demonstrated, only assay 3 (Farrzyme, TBS, UK) and 5 (Farr-RIA, Trinity Biotech, Ireland) are really suitable to detect primarily high avidity aDNA-Ab. Both were significantly linked to lupus nephritis (specificity 84%) and highly specific for SLE (95 and 96%). Thereby, assay 3 was found to be the first solid phase ELISA probably suitable to replace the Farr-RIA. Classical ELISAs (assay 1, Orgentec, Germany, and 2, Bindazyme, TBS, UK), detecting aDNA-Ab more or less independent from their avidity, or tests with only intermediate specificity for high avidity Ab (assay 4, ELIAdn, Sweden Diagnostics, Germany), were less specific for SLE (83, 79, 91%, respectively) and not associated with renal involvement (specificity 54-57%). At least in the patients studied here, obvious antigen-related differences could not be observed. With slight differences, all assays were suitable to monitor disease activity and therapy in SLE, agreeing with the ECLAM score in about 70-80% of cases. For lupus nephritis, aC1q-Ab are as specific as high avidity aDNA-Ab and capable to close a diagnostic gap in some cases. Thus, to enhance the specificity (up to 98%) and to consider the distinct diagnostic/pathogenic potential of aDNA-Ab subtypes in SLE, under routine clinical laboratory conditions it should be recommended to combine a sensitive screening test with a more specific second assay.     

系统性红斑狼疮患者血清C1q抗体的检测及临床意义

目的研究C1q抗体与系统性红斑狼疮(SLE)病情活动和脏器损害的相关性,探讨C1q抗体对SLE疗效及预后的影响。方法用酶联免疫吸附试验(ELISA)检测86例活动期SLE患者血清中的C1q抗体,并对全部病例进行随访,以尿蛋白转阴性和病情初步缓解为随访终点,每半个月进行1次终点的评估。结果56例(65%)SLE患者血清C1q抗体阳性,抗体水平(83±39)U/ml;血清C1q抗体浓度与SLEDAI评分、尿蛋白含量以及抗dsDNA抗体滴度呈正相关(P<0.001),与补体C3、C4水平呈负相关(P<0.001);C1q抗体(+)组患者的肾损害发生率明显高于C1q抗体(-)组(P<0.001);C1q抗体浓度和补体C3是影响SLE疗效的独立因素[相关危险度(RR值)0.99,95%可信区间(CI)0.98~0.997,P=0.010和RR值3.18,95%CI1.05~9.65,P=0.041];C1q抗体(+)与C1q抗体(-)的狼疮肾炎患者尿蛋白转阴的时间经Log-rank检验差异有显著性(字2=4.10,P=0.0428)。结论C1q抗体与SLE的发生、发展密切相关。C1q抗体不仅反映SLE病情的活动性,而且对判断脏器损害情况、评价疗效及预后均有重要意义。     

Simultaneous detection of anti-C1q and anti-double stranded DNA autoantibodies in lupus nephritis: predictive value for renal flares

Clinical difficulties in predicting systemic lupus erythematosus (SLE) renal flares are still encountered. Biological markers such as autoantibodies (aAbs) may be of major interest for clinicians in the follow-up of SLE patients. The aim of our study was to investigate the clinical utility of one of these biological markers, anti-C1q aAbs, in predicting renal flares of SLE nephritis in comparison with the 'gold standard' anti-double stranded DNA (anti-dsDNA) aAbs. Anti-C1q aAbs and anti-dsDNA aAbs were analysed through a longitudinal retrospective study of 23 SLE patients presenting with one or more renal flares. Anti-C1q and/or anti-dsDNA aAbs were found in 20 (87%) of 23 patients, of whom 16 (69%) displayed both. Thirty-three renal flares occurred during the course of the study, and anti-C1q aAbs and anti-dsDNA aAbs were positive in 25 (76%) and 24 (73%) of these flares respectively. The sensitivity of anti-C1q and/or anti-dsDNA aAbs in predicting renal flares reached 85%. The specificity of anti-C1q aAbs was 84%, of anti-dsDNA aAbs 77% and of both aAbs 97%. Positive and negative predictive values were as follows: 56% and 70% for anti-C1q aAbs, 53% and 72% for anti-dsDNA aAbs. The combination of both aAbs had the highest positive predictive value (69%), whereas absence of both aAbs was associated with the highest negative predictive value (74%). In conclusion, our results confirm that anti-C1q aAbs are present in a significant percentage of SLE patients with active renal involvement, suggesting that these aAbs could be a useful additional marker. The presence of anti-C1q and anti-dsDNA aAbs was associated with a high risk of renal flare, whereas the absence of both aAbs excluded such an event. These data confirm that systematic detection of anti-C1q and anti-dsDNA aAbs is of interest for the follow-up in SLE patients with renal involvement.     

血清C1q抗体水平与系统性红斑狼疮活动性和狼疮肾炎的关系

目的分析探讨血清C1q抗体水平与系统性红斑狼疮（SLE）活动性以及狼疮肾炎之间的关系。方法采用ELISA方法检测92例SLE患者C1q抗体水平。并与其他SLE活动性指标进行相关分析。结果SLE患者C1q抗体阳性率为67.4%。活动性狼疮组的C1q抗体阳性率及C1q抗体水平显著高于非活动性狼疮组（P〈0.001）。活动性狼疮肾炎组C1q抗体阳性率（P〈0.05）和C1q抗体水平（P〈0.01）显著高于非活动性狼疮肾炎组。联合抗dsDNA抗体检测,没有1例活动性狼疮肾炎患者的C1q抗体和抗dsDNA抗体同时阴性。结论血清C1q抗体与狼疮活动以及活动性狼疮肾炎关系密切,C1q抗体的检测有助于活动性狼疮的诊断,联合抗dsDNA抗体的检测是活动性狼疮肾炎的特异性检测指标。     

Association between ongoing anti-C1q antibody production in peripheral blood and proliferative nephritis in patients with active systemic lupus erythematosus

The aim of this study was to compare ongoing production of anti-C1q antibodies (anti-C1q) in peripheral blood with serum anti-C1q levels in patients with systemic lupus erythematosus (SLE), especially in patients with nephritis. Using the ELISPOT technique for the detection of IgG and IgA anti-C1q production, 21 patients with active SLE were investigated. ELISAs for IgG and IgA anti-C1q were compared with the ELISPOT results. Six of the patients were found to have proliferative nephritis (WHO grade III/IV) confirmed by renal biopsy. High numbers of IgG anti-C1q spot-forming cells (SFC), defined as > 20/10(5) plated peripheral blood mononuclear cells (PBMC), were exclusively observed in patients with proliferative nephritis (P < 0.0001). Serum levels of IgG anti-C1q were significantly increased in patients with proliferative nephritis (P = 0.039). High ongoing IgG anti-C1q production was observed in all patients with proliferative nephritis, which may be a contributory factor in the pathogenesis of this disorder. The detection of IgG anti-C1q production may be valuable in the clinical investigation of patients with suspected SLE nephritis.      

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.     

A prospective study of anti-chromatin and anti-C1q autoantibodies in patients with proliferative lupus nephritis treated with cyclophosphamide pulses or azathioprine/methylprednisolone

OBJECTIVE: To study the prevalence and course of anti-chromatin (anti-nucleosome, anti-double-stranded (ds) DNA and anti-histone) and anti-C1q autoantibodies in patients with proliferative lupus nephritis (LN), treated in a randomised controlled trial with either cyclophosphamide or azathioprine plus methylprednisolone. METHODS: Autoantibody levels were measured and analysed in 52 patients with proliferative LN, during their first year of treatment. Levels in both treatment arms were compared and associations with clinical, serological and outcome parameters were studied. RESULTS: At study entry, prevalences for anti-nucleosome, anti-dsDNA, anti-histone and anti-C1q autoantibodies were 81%, 96%, 23% and 65%, respectively. Anti-chromatin autoantibodies correlated with each other, but not with anti-C1q levels. If patients were divided for their autoantibody titre at the start of treatment above or below the median, the only significant differences were higher SLE disease activity index with higher anti-nucleosome, and higher creatinine with higher anti-C1q autoantibodies. During the first year, a comparable rapid decline in the levels of anti-nucleosome, anti-dsDNA and anti-C1q autoantibodies was seen in both treatment arms. Anti-histone autoantibody levels were low and did not change. Renal flares were not preceded by rises in autoantibody titres. CONCLUSIONS: These results indicate that measurement of anti-chromatin and anti-C1q autoantibodies is useful for diagnosing LN, but not for monitoring disease course.     

Diagnostic value of progranulin in patients with lupus nephritis and its correlation with disease activity

The aim of this study was to explore whether progranulin (PGRN) can be a useful marker not only for accurate diagnosis of patients with active lupus nephritis (LN), but also for prediction of the disease activity in this population. A total of 154 LN patients were enrolled in this study, 76 of which were diagnosed as having active LN and 78 as having stable LN. Additionally, 71 age-matched non-LN patients were enrolled as controls. The serum and urine PGRN levels of each study population were measured using the enzyme-linked immunosorbent assay method. The diagnostic performance of both indicators and their correlation with the disease activity of LN were systematically investigated using receiver operating characteristic (ROC) analysis and correlation analysis. The active LN population had significantly higher serum and urine PGRN levels than the other two populations. ROC analysis further demonstrated that these two indicators, particularly in combination, appear to have a strong performance in discriminating active LN patients from the rest of the LN population. In the active LN population, serum and urine PGRN levels were not only significantly correlated with SLEDAI score, rSLEDAI score, and activity index, but also had a considerable association with several key markers reflecting the disease activity of LN, including serum levels of complement component 3 and ds-DNA. Nevertheless, neither of the two indicators were correlated with the pathological classification of LN, chronicity index, serum creatinine level, and 24-h urine protein levels. Our findings demonstrate that PGRN may have great potential as a diagnostic factor for active LN and as a predictor for its disease activity.     

Anti-chromatin and anti-C1q antibodies in systemic lupus erythematosus compared to other systemic autoimmune diseases

OBJECTIVE: To evaluate the prevalence, sensitivity, and specificity of anti-chromatin and anti-C1q antibodies in systemic lupus erythematosus (SLE) and lupus nephritis compared to small vessel vasculitis and other connective tissue diseases. To provide long-term follow-up data for anti-chromatin antibodies in lupus nephritis. METHODS: We determined the significance of anti-nuclear antibodies (ANA), anti- double-stranded DNA (anti-dsDNA), anti-chromatin, and anti-C1q antibodies, as well as complement factors C3 and C4, in relation to disease activity in SLE patients with (n = 47; long-term follow-up data for 33 patients) and without (n = 31) biopsy-confirmed lupus nephritis, microscopic polyangiitis (n = 37), Wegener's granulomatosis (n = 66), primary Sj?gren's syndrome (n = 17), limited scleroderma (CREST syndrome) (n = 6), and progressive systemic scleroderma (PSS) (n = 11). RESULTS: Anti-chromatin antibodies were more specific and sensitive than anti-C1q antibodies in distinguishing SLE patients from those with other systemic autoimmune diseases [anti-chromatin: sensitivity 64.1%, specificity 99.2%, odds ratio (OR) 219.6; anti-C1q: sensitivity 50%, specificity 72.6%, OR 2.65]. Anti-C1q antibodies were present in 75% of patients with Sj?gren's syndrome and 35.1% of patients with microscopic polyangiitis. Anti-chromatin antibodies could identify SLE in patients with positive ANA but negative anti-dsDNA antibodies. Persisting anti-chromatin antibodies indicated SLE disease activity, even if anti-dsDNA antibodies had become negative. In long-term follow-up, those SLE patients with negative anti-dsDNA antibodies but persisting ANA and anti-chromatin antibodies relapsed if immunosuppression had been tapered. Anti-chromatin antibodies correlated with the SLE disease activity index (SLEDAI) as a marker of disease activity. CONCLUSIONS: The measurement of anti-chromatin, but not anti-C1q, antibodies in patients with systemic autoimmune diseases increases diagnostic sensitivity and specificity for SLE and assists in treatment decisions in anti-dsDNA-negative patients.     

系统性红斑狼疮FcγRⅡb和C1q抗体的表达及其意义

目的 探讨系统性红斑狼疮(SLE)患者外周血单个核细胞FcγRⅡb和血清C1q抗体的表达及其在SLE发病机制中的意义。方法 32例SLE和22例正常人外周血粒细胞、淋巴细胞和单核细胞FcγRⅡb的表达采用流式细胞仪测定，血清C1q抗体采用ELISA法测定，并将FcγRⅡb和C1q抗体的表达分别与抗核抗体(ANA)、抗dsDNA抗体及SLEDAI评分作相关性分析。结果 SLE患者外周血粒细胞、淋巴细胞和单核细胞FcγRⅡb的表达均减少。以粒细胞和单核细胞为著，血清C1q抗体水平明显增高，且FcγRⅡb和C1q抗体与ANA、抗dsDNA及系统性红斑狼疮活动指数(SLEDAI)评分分别呈负相关和正相关；FcγRⅡb与C1q抗体呈低-中度负相关。结论 SLE患者外周血单个核细胞FcγRⅡb表达缺陷和血清C1q抗体水平升高，使免疫复合物的清除功能下降，这在SLE的免疫发病机制中起重要作用，FcγRⅡb和C1q抗体是判断病情活动性的重要指标。     

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.     

Anti-C1q antibodies are associated with systemic lupus erythematosus disease activity and lupus nephritis in northeast of China

This study aimed to investigate the associations of anti-C1q antibodies with systemic lupus erythematosus (SLE) disease activity and lupus nephritis (LN) in northeast of China. Ninety patients with SLE, 37 patients with other autoimmune diseases, and 40 healthy donors in northeast of China were enrolled. Serum anti-C1q antibodies were measured by ELISA with 20 RU/ml as the threshold of positive results. The prevalence and levels of anti-C1q antibodies in SLE group (50%, 20.54 ± 34.67 RU/ml) were significantly higher than those in autoimmune disease and healthy control groups (P < 0.05), yet no significant difference between LN patients and non-LN lupus patients (57.14% vs 41.46%, P > 0.05; 25.92 ± 39.94 vs 13.07 ± 27.39 RU/ml, P > 0.05). Anti-C1q antibody levels were positively correlated with levels of Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores, anti-dsDNA, and anti-cardiolipin and negatively correlated with serum C3 and C4 (P < 0.05). The prevalence of anti-Sm and anti-nucleosome increased in anti-C1q-positive lupus patients (P < 0.05). Compared with anti-C1q-negative lupus patients, patients with 20–40 RU/ml anti-C1q antibodies had comparable disease activity (P > 0.05); patients with 40–80 RU/ml anti-C1q antibodies had significantly lower levels of serum complement (P < 0.05); patients with above 80 RU/ml anti-C1q antibodies had much more severe hypocomplementemia, increased SLEDAI scores, and higher incidence of hematuria and proteinuria (P < 0.05). Furthermore, the specificity and positive predictive value of 80 RU/ml anti-C1q antibodies for LN was 97.56% and 87.50%, respectively. In conclusion, anti-C1q antibodies are associated with SLE and LN disease activity, and the contribution hinges on the titers. Moreover, high-level anti-C1q antibodies are valuable for diagnosing LN.     

抗嗜中性粒细胞胞浆抗体与狼疮性肾炎的关系

目的探讨抗嗜中性粒细胞胞浆抗体（ANCA）与狼疮性肾炎（LN）临床相关表现和发病机制的关系。方法分别应用间接免疫荧光法和酶联免疫吸附分析的方法,检测81例LN患者血清中的ANCA,并分析ANCA与LN临床表现和其它实验室检查结果之间的关系。结果单用间接免疫荧光法检测时,ANCA在LN中的阳性率是30.9％（25／81）。对间接免疫荧光法检测为阳性的血清,用酶联免疫吸附分析法进行验证,结果仅有72.0％（18／25）仍为阳性,全部是核周型ANCA（p-ANCA）,未见中央型ANCA（c-ANCA）出现。ANCA阳性组LN患者合并浆膜炎、神经系统累及、贫血、抗ds-DNA抗体阳性和低补体的频率均显著高于ANCA阴性组LN患者。结论ANCA在LN中的阳性率为30.9％,并与LN特定的临床表现相关,提示ANCA可能参与了LN的发病过程。     

Anti-C1q antibodies in nephritis: correlation between titres and renal disease activity and positive predictive value in systemic lupus erythematosus

OBJECTIVE: To investigate antibodies to complement 1q (anti-C1q) and investigate the correlation between anti-C1q titres and renal disease in systemic lupus erythematosus (SLE). METHODS: 151 SLE patients were studied. In patients with biopsy proven lupus nephritis (n = 77), activity of renal disease was categorised according to the BILAG renal score. Sera were tested for anti-C1q by enzyme immunoassay. Serum samples were randomly selected from 83 SLE patients who had no history of renal disease, and the positive and negative predictive value of the antibodies was studied. RESULTS: Patients with active lupus nephritis (BILAG A or B) had a higher prevalence of anti-C1q than those with no renal disease (74% v 32%; relative risk (RR) = 2.3 (95% confidence interval, 1.6 to 3.3)) (p<0.0001). There was no significant difference in anti-C1q prevalence between SLE without nephritis and SLE with non-active nephritis (BILAG C or D) (32% v 53%, p = 0.06) or between active and non-active nephritis (74% v 53%, p = 0.06). Patients with nephritis had higher anti-C1q levels than those without nephritis (36.0 U/ml (range 4.9 to 401.0) v 7.3 U/ml (4.9 to 401.0)) (p<0.001). Anti-C1q were found in 33 of 83 patients (39%) without history of renal disease. Nine of the 33 patients with anti-C1q developed lupus nephritis. The median renal disease-free interval was nine months. One patient with positive anti-C1q was diagnosed as having hypocomplementaemic urticarial vasculitis syndrome during follow up. CONCLUSIONS: Anti-C1q in SLE are associated with renal involvement. Monitoring anti-C1q and their titres in SLE patients could be important for predicting renal flares.     

Antiphospholipid antibodies in patients with proliferative and membranous lupus nephritis

Clinical Rheumatology - The aim of this study was to investigate the role of antiphospholipid antibodies (aPLs) in patients with proliferative and membranous lupus nephritis (LN). Patients...