Distinct roles of CSF-1 isoforms in lupus nephritis

Colony-stimulating factor-1 (CSF-1), the principal growth factor for macrophages, is increased in the kidney, serum, and urine of patients with lupus nephritis, and eliminating CSF-1 suppresses lupus in MRL-Fas(lpr) mice. CSF-1 has three biologically active isoforms: a membrane-spanning cell surface glycoprotein (csCSF-1), a secreted proteoglycan (spCSF-1), and a secreted glycoprotein (sgCSF-1); the role of each isoform in the circulation and kidney in autoimmune disease is not well understood. Here, we constructed mutant MRL-Fas(lpr) mice that only express csCSF-1 or precursors of the spCSF-1 and sgCSF-1 isoforms. Both csCSF-1 and spCSF-1 shifted monocytes toward proinflammatory, activated populations, enhancing their recruitment into the kidney during lupus nephritis. With advancing lupus nephritis, spCSF-1 was the predominant isoform responsible for increasing circulating CSF-1 and, along with the csCSF-1 isoform, for increasing intrarenal CSF-1. Thus, csCSF-1 appears to initiate and promote the local activation of macrophages within the kidney. Intrarenal expression of csCSF-1 and spCSF-1 increases with advancing nephritis, thereby promoting the intrarenal recruitment of monocytes and expansion of Ly6C(hi) macrophages, which induce apoptosis of the renal parenchyma. Taken together, these data suggest that the three CSF-1 isoforms have distinct biologic properties, suggesting that blocking both circulating and intrarenal CSF-1 may be necessary for therapeutic efficacy.     

Circulating CSF-1 Promotes Monocyte and Macrophage Phenotypes that Enhance Lupus Nephritis

Macrophages mediate kidney disease and are prominent in a mouse model (MRL-Fas^lpr) of lupus nephritis. Colony stimulating factor-1 (CSF-1) is the primary growth factor for macrophages, and CSF-1 deficiency protects MRL-Fas^lpr mice from kidney disease and systemic illness. Whether this renoprotection derives from a reduction of macrophages and whether systemic CSF-1, as opposed to intrarenal CSF-1, promotes macrophage-dependent lupus nephritis remain unclear. Here, we found that increasing systemic CSF-1 hastened the onset of lupus nephritis in MRL-Fas^lpr mice. Using mutant MRL-Fas^lpr strains that express high, moderate, or no systemic CSF-1, we detected a much higher tempo of kidney disease in mice with the highest level of CSF-1. Furthermore, we uncovered a multistep CSF-1-dependent systemic mechanism central to lupus nephritis. CSF-1 heightened monocyte proliferation in the bone marrow (SSC^lowCD11b⁺), and these monocytes subsequently seeded the circulation. Systemic CSF-1 skewed the frequency of monocytes toward “inflammatory” (SSC^lowCD11b⁺Ly6C^high) and activated populations that homed to sites of inflammation, resulting in a more rapid accumulation of intrarenal macrophages (CD11b⁺CSF-1R⁺ or CD68⁺) that induced apoptosis of tubular epithelial cells, damaging the kidney. In humans, we found increased levels of CSF-1 in the serum, urine, and kidneys of patients with lupus compared with healthy controls. Furthermore, serum and urine CSF-1 levels correlated with lupus activity, and intrarenal CSF-1 expression correlated with the histopathology activity index of lupus nephritis. Taken together, circulating CSF-1 is a potential therapeutic target for lupus nephritis.Identifying molecules that mediate experimental lupus nephritis may uncover therapeutic targets and biomarkers. MRL-Fas^lpr mice develop a systemic autoimmune disease akin to human lupus nephritis and thus are a powerful tool to probe for molecules that regulate kidney disease in these patients.^1,2 Kidney disease in MRL-Fas^lpr mice is rapid, progressive, and predictable.³ Moreover, the time frame is sufficiently slow to tease apart the pathogenesis, and sufficiently fast to be efficient. Thus, these mice are a powerful tool to probe for therapeutic targets and biomarkers in human lupus nephritis.Macrophages (Mø) regulate kidney disease.⁴ Mø originate from pluripotent stem cells in the bone marrow that differentiate into mature monocytes (Mo), which enter the blood stream^5,6 and traffic to the kidney. Growing evidence implicates Mø as mediators of lupus nephritis because intrarenal Mø (CD68⁺, F4/80⁺) increase with advancing disease in MRL-Fas^lpr mice.⁷ Mø require the colony stimulating factor-1 (CSF-1), their principle growth factor, to differentiate, survive, and multiply.⁸ Our prior studies indicate that CSF-1 is central to lupus nephritis. Implanting cells generating CSF-1 into the kidney of MRL-Fas^lpr mice incites local Mø-rich inflammation.^9,10 Moreover, CSF-1-deficient mice (Csf1^op/op;MRL-Fas^lpr) are protected from kidney disease and systemic illness.^11,12 However, the Csf1^op/op;MRL-Fas^lpr mice are frail and have skeletal abnormalities and numerous other defects.^13–16 Thus, it is possible that the effect of deleting CSF-1 on lupus in MRL-Fas^lpr mice is, at least in part, not directly related to the reduction of Mø. Moreover, CSF-1-generating cells implanted into the kidney induce inflammation that is restricted to the area adjacent to the implant site.⁹ Thus, the systemic effect of CSF-1 during the initiation and progression of Mø-dependent lupus nephritis remains unclear.Understanding the effect of circulating and tissue CSF-1 expression is key to designing a therapeutic treatment. CSF-1 is expressed in the circulation and is upregulated in the kidney in MRL-Fas^lpr mice with lupus nephritis.^17–19 Intrarenal CSF-1 expression occurs during inflammation and expression is largely limited to tubular epithelial cells (TECs).²⁰ Moreover, the rise in circulating CSF-1 precedes intrarenal CSF-1 expression and is bimodal in MRL-Fas^lpr mice. CSF-1 is upregulated in neonates, declines to normal levels, and then progressively rises with advancing kidney disease in MRL-Fas^lpr mice.¹⁹ Moreover, an increase in CSF-1 in the circulation precedes overt kidney pathology in MRL-Fas^lpr mice.^18,19 However, it is not clear whether CSF-1 in the circulation, apart from intrarenal CSF-1, is central to the progression of lupus nephritis in MRL-Fas^lpr mice. Therefore, we propose to test the hypothesis that systemic CSF-1 hastens the progression of Mø-rich lupus nephritis. Furthermore, we hypothesize that circulating CSF-1 increases the frequency of circulating Mo (SSC^lowCD11b⁺), which are more readily recruited to the kidney and, in turn, induce injury.Finally, preclinical studies are a first step in identifying therapeutic targets and biomarkers for lupus nephritis and require validation in humans. Therefore, we propose to test the hypothesis that CSF-1 is upregulated in the circulation, urine, and kidneys of patients with active lupus nephritis.     

狼疮肾炎患者血清和尿白细胞介素-18水平检测及其临床意义

目的：检测狼疮肾炎(LN)患外周血清和尿液白细胞介素—18(IL—18)水平并探讨其临尿意义。方法：血清和尿液IL-18含量采用酶联免疫吸附方法(ELISA)。结果：LN组血清IL—18水平显高于正常对照组(P＜0、01)，活动期LN血清IL—18水平显高于缓解期患(P＜0．01)3LN组尿IL—18水平显高于正常对照组(P＜0．05)，活动期LN患尿IL—18水平显高于缓解期患(P＜0．05)。LN患血清IL—18水平与SLEDAI、抗dsDNA抗体成正相关关系，与补体C3呈负相关关系，而与血白蛋白、血肌酐无相关关系；活动期LN患尿IL—18水平与狼疮肾组织活动性指数(AI)、24h尿蛋白排泄量均呈正相关关系。结论：LN血清和尿IL—18水平显增高，IL—18可能在LN的病理生理过程中起重要作用。LN血清和尿IL—18水平均与狼疮病情活动密切相关，可作为判断狼疮疾病活动性的候选参考指标。     

Measurement of urinary chemokine and growth factor messenger RNAs: a noninvasive monitoring in lupus nephritis

Noninvasive molecular tests of urine cells have been developed to monitor the activity of kidney diseases. We evaluate whether measurement of urinary messenger RNA (mRNA) levels of chemokine and growth factor genes could distinguish between diffuse proliferative lupus nephritis (class IV LN) and others and whether it is able to predict the response to therapy. Prebiopsy urine samples were collected from 26 LN patients. Urine specimens were serially collected over a period of 6 months from class IV LN patients who were receiving standard immunosuppressive treatments. Urinary interferon-producing protein 10 and its CXC chemokine receptor (CXCR)3, transforming growth factor-beta (TGF-beta), and vascular endothelial growth factor (VEGF) mRNA levels were analyzed by quantitative real-time polymerase chain reactions. Levels of chemokine or growth factor mRNAs in urine could distinguish class IV LN from others, with a sensitivity of 85% and a specificity of 94%. The receiver-operative characteristic curve demonstrated that urine mRNA levels of these genes could identify active class IV LN with an accuracy greater than the current available clinical markers, namely systemic lupus erythematosus (SLE) disease activity index, proteinuria, renal function, or urinalysis. A significant reduction of interferon-producing protein 10 (IP-10), CXCR3, TGF-beta, and VEGF mRNA levels from baselines was observed in patients who responded to therapy, whereas the levels tended to increase in those who resisted to treatment. Measurement of urinary chemokine and growth factor mRNAs can precisely distinguish class IV LN from others. Temporal association between these markers and therapeutic response is demonstrated. This noninvasive approach serves as a practical tool in diagnosis and management of LN.     

激素联合来氟米特治疗狼疮性肾炎疗效的观察

目的 了解来氟米特治疗Ⅳ型狼疮性肾炎的临床效果、安全性和不良反应.方法 59例狼疮性肾炎患者的肾活组织检查(简称活检)显示为狼疮性肾炎,应用来氟米特联合糖皮质激素治疗6个月.用药期间监测血、尿常规、24 h尿蛋白定量、肝、肾功能、抗核抗体及抗双链抗体滴度、红细胞沉降率和补体C3等,6个月后行疗效和安全性的评价.结果 来氟米特治疗狼疮性肾炎尿蛋白缓解率为72.4%,高于环磷酰胺冲击治疗缓解率(57%),狼疮性肾炎活动性指标缓解率也高于后者.结论 来氟米特联合糖皮质激素治疗能有效地控制狼疮活动且不良反应轻,耐受性好.     

血清趋化因子的表达水平与其狼疮肾炎血浆吸附远期疗效的关系分析

目的 探讨狼疮肾炎血浆吸附的远期疗效及其与血清趋化因子水平的关系.方法 选取行血浆吸附治疗的狼疮肾炎患者32例为研究组,均随访至少2年,检测统计患者的24h尿蛋白定量水平及其2年复发率.另选取30例同期进行健康体检者为对照组.采用酶联免疫吸附法检测2组血清趋化因子5(CCL5)、巨噬细胞炎症蛋白1α(MIP-1oα)、巨噬细胞炎症蛋白1β(MIP-1β)等趋化因子水平并分析狼疮肾炎血浆吸附患者血清趋化因子水平与其24h尿蛋白定量水平的关系.比较复发和无复发患者的血清趋化因子水平并分析其血清趋化因子水平与其复发的关系及其预测其复发的价值.结果 与对照组比较,研究组治疗前的血清CCL5、MIP-1α、MIP-1β等趋化因子水平和24 h尿蛋白定量水平均升高(P＜0.05).与治疗前比较,研究组治疗后和随访期间的血清趋化因子水平均降低(P＜0.05).研究组随访2年复发率为68.75％(22/32),且复发患者治疗前后和随访期间的血清趋化因子水平均高于无复发患者(P＜0.05).狼疮肾炎血浆吸附患者血清CCL5、MIP-1 α、MIP-1β与其24 h尿蛋白定量水平及其复发均相关(P＜0.05).且狼疮肾炎血浆吸附患者治疗前后血清趋化因子水平单独和联合预测其复发的价值良好,其中以治疗后血清趋化因子水平联合预测其复发的价值最佳.结论 血清趋化因子水平与狼疮肾炎血浆吸附远期疗效明显相关且对其复发的预测价值良好,可能作为其远期疗效评估的参考指标.     

The Pathogenesis of Lupus Nephritis

Lupus nephritis is an immune complex GN that develops as a frequent complication of SLE. The pathogenesis of lupus nephritis involves a variety of pathogenic mechanisms. The extrarenal etiology of systemic lupus is based on multiple combinations of genetic variants that compromise those mechanisms normally assuring immune tolerance to nuclear autoantigens. This loss of tolerance becomes clinically detectable by the presence of antinuclear antibodies. In addition, nucleic acids released from netting or apoptotic neutrophils activate innate and adaptive immunity via viral nucleic acid-specific Toll-like receptors. Therefore, many clinical manifestations of systemic lupus resemble those of viral infection. In lupus, endogenous nuclear particles trigger IFN-α signaling just like viral particles during viral infection. As such, dendritic cells, T helper cells, B cells, and plasma cells all contribute to the aberrant polyclonal autoimmunity. The intrarenal etiology of lupus nephritis involves antibody binding to multiple intrarenal autoantigens rather than the deposition of circulating immune complexes. Tertiary lymphoid tissue formation and local antibody production add to intrarenal complement activation as renal immunopathology progresses. Here we provide an update on the pathogenic mechanisms that lead to lupus nephritis and provide the rationale for the latest and novel treatment strategies.SLE is a chronic autoimmune disease characterized by loss of tolerance against nuclear autoantigens, lymphoproliferation, polyclonal autoantibody production, immune complex disease, and multiorgan tissue inflammation.^1,2 SLE used to be referred to as a complex autoimmune disease of unknown etiology; however, during the last decade, a multidisciplinary approach to SLE research has built a more concise view of its pathogenesis and for lupus nephritis (LN). Here we briefly summarize an updated working model of SLE and LN, which provides a rationale for novel therapies.     

Plasma, urine, and renal expression of adiponectin in human systemic lupus erythematosus

BACKGROUND: Adiponectin is an adipocyte-derived cytokine that has anti-inflammatory properties. A preliminary proteomic evaluation of urine for biomarkers of systemic lupus erythematosus (SLE) nephritis demonstrated high levels of adiponectin in SLE urine. This prompted investigation of adiponectin expression in human SLE. METHODS: Adiponectin was measured by enzyme-linked immunosorbent assay (ELISA) in the urine and plasma of a clinically well-characterized SLE cohort, with renal and nonrenal SLE being followed in a prospective longitudinal study to identify risk factors for SLE flare. Renal adiponectin expression was assessed by immunohistochemical analysis of kidney biopsies from SLE nephritis patients. RESULTS: Cross-sectional testing showed that plasma adiponectin levels were higher in patients with renal SLE flare than normal controls or patients with nonrenal SLE flare, after accounting for race and body mass index. Urine adiponectin levels increased significantly with renal flare, but not nonrenal SLE flare. Longitudinal testing revealed that the urine adiponectin increase began in the 2 months prior to renal flare. Urine adiponectin correlated with plasma levels and magnitude of proteinuria, and to a lesser extent serum creatinine. Plasma adiponectin levels were independent of renal function and proteinuria. In kidney biopsies, adiponectin was found on endothelial surfaces in normal and SLE kidneys, and on podocytes and in the tubules of SLE kidneys. CONCLUSION: Plasma adiponectin levels are increased in patients with renal SLE compared to healthy controls and patients with nonrenal SLE. During renal but not nonrenal SLE flare, urine adiponectin levels increase significantly. Urine adiponectin may be a biomarker of renal SLE flare.     

Lupus nephritis in children: prognostic significance of clinicopathological findings

BACKGROUND: We aimed to review our experience with childhood lupus nephritis (LN) in respect to the analysis of the clinical and histopathological presentation of LN and prognostic factors affecting the kidney and patient outcomes. METHOD: Forty-three children (39 girls, 4 boys) with biopsy-proven LN were included in the study. The mean age of the children was 12.0 +/- 2.8 years. Based on the renal histopathology and clinical presentation, patients were treated with oral prednisone, intravenous pulses of methylprednisolone or intravenous cyclophosphamide. The final clinical status was classified as follows: (1) renal and extrarenal remission; (2) clinically active renal disease, or (3) adverse outcome, i.e., end-stage renal failure (ESRF) or death. RESULTS: The mean duration of follow-up was 7.2 +/- 2.8 years (1 month to 14.2 years). All 43 children had hematuria and 53.5% had proteinuria at admission. Fourteen children were in nephrotic status at the onset of disease. Class IV (diffuse proliferative) nephritis was observed in 29 patients as the most frequent histopathology (67.4%). The patients with class IV nephritis had a tendency to develop nephrotic syndrome, heavy proteinuria, increased Cr levels and persistent hypertension at initial evaluation. Thirty-two of 43 children (74.4%) were in renal remission at the last visit. Five-year kidney and patient survival rates from the time of diagnosis to the endpoints of ESRF or death were 83.7 and 90.7% respectively in the whole group while it was 75.9 and 86.2% respectively in the class IV group. Adverse outcome was significantly associated with the persistent hypertension, anemia, high serum Cr level, heavy proteinuria, nephrotic syndrome and class IV nephritis at presentation. CONCLUSION: We can conclude that the prognosis of LN in children is primarily dependent on the histopathological lesions. Severity of the clinical renal disease at admission and presence of persistent hypertension are the main poor prognostic factors rather than age, gender, low C3 and C4 levels, ANA positivity and the treatment modalities in Turkish children.     

Post-transplant Lupus Nephritis Recurrence: A Case Report and Review of the Literature

Despite progress in treating lupus nephritis, the incidence of end-stage chronic kidney disease has increased. Renal transplantation is the treatment of choice for these patients and has been successfully performed on systemic lupus erythematosus (SLE) since 1959. The main concern in these patients is post-transplant lupus nephritis recurrence. Several questions remain for SLE patients following transplantation, including fear of lupus nephritis recurrence, choice of immunosuppressive therapy, and how to manage the disease and associated complications to reduce morbidity and risk of death.     

Urinary monocyte chemoattractant protein-1 correlates with disease activity in lupus nephritis

Monocyte chemoattractant protein-1 (MCP-1) has a pathogenic role in murine lupus nephritis (LN). We recruited 25 pediatric and adolescent systemic lupus erythematosus (SLE) patients from our lupus clinic [13 (52%) patients with LN and 12 (48%) lupus non-nephritis patients] and evaluated their urinary and plasma MCP-1 levels compared to adult and childhood controls. The median age and SLE disease duration of patients were 14.4 and 5.5 years, respectively. LN patients had a higher median renal (p?=?0.01) British Isles Lupus Assessment Group (BILAG) index, with a tendency for higher total BILAG scores (p?=?0.2). There were significantly increased urinary MCP-1 levels in the LN patients compared to healthy controls (p?<?0.001) whose values were significantly higher than lupus non-nephritis children (p<?0.004). Urinary MCP-1 levels correlated well with total BILAG scores (r?=?0.82, p?=?0.04). There were no differences in plasma MCP-1 levels between SLE patient groups and pediatric controls, although the levels in the childhood controls were elevated compared to those of the adult controls (p?<?0.04). These results provide evidence of increased urinary—but not plasma—MCP-1 levels in children with LN, which correlates well with SLE disease activity as measured by the BILAG index.     

狼疮性肾炎患者血浆与肾组织抗中性粒细胞胞浆抗体的表达

目的探讨抗中性粒细胞胞浆抗体（ANCA）在狼疮性肾炎（LN）患者血浆及肾组织中的表达及其意义。方法回顾性分析40例LN患者的临床资料及ANCA检测结果,按。肾脏病变活动性评分、系统性红斑狼疮疾病活动性指数（SLEDAI）评分、尿蛋白含量进行分类统计。结果血浆ANCA阳性率为37.5％,肾组织ANCA阳性率为42.5％,两者呈正相关性（r=0.765,P=0.013）,但无统计学差异。肾脏活动性病变组的血浆ANCA和肾组织ANCA阳性率均高于肾脏慢性化病变组（P〈0.05,P〈0.01）,高尿蛋白组肾组织ANCA阳性率明显高于低尿蛋白组（P〈0.01）。结论ANCA可作为判断狼疮性肾炎（LN）肾脏病变及临床活动性的重要参考指标。     

The correlation analysis between the neutrophil-lymphocyte ratio and systemic lupus erythematosus viscera involvement and disease activity

Objective To investigate the correlation between neutrophil-lymphocyte ratio (NLR) and disease activity of systemic lupus erythematosus (SLE), and the changes of NLR in different organ involvement of SLE patients. Methods A total of 155 SLE patients and 135 healthy controls from the Rheumatology Department of Xiangya Hospital were enrolled in this study from 2010 to 2018. Patients with SLE were divided into lupus nephritis group (LN group) and non-lupus nephritis group (non-LN group), serositis group and non-serositis group, according to whether they had kidney involvement or serositis. According to the SLE disease activity index 2000(SLEDAI-2000), the patients were divided into mild to moderate disease activity group (SLEDAI score＜15) and severe disease activity group (SLEDAI score≥15). The NLR values of the above groups were compared. Spearman's correlation analysis was used to analyze the correlation between NLR and SLE patients' laboratory indexes. Multiple linear regression model was used to analyze the relationship between NLR and SLE disease activity. Receiver operating characteristic curve (ROC) was used to evaluate the value of NLR in SLE diagnosis and activity assessment. Results (1)The NLR value of SLE patients was significantly higher than that of healthy control group, and the difference was statistically significant (P＜0.01). (2)The NLR value of SLE patients in the LN group was higher than that in the non-LN group, and the NLR value of SLE patients with serositis was higher than that in the group without serositis, with statistically significant differences (both P＜0.05). (3)The NLR value of SLE patients in the severe disease activity group was higher than that in the mild and moderate disease activity group, and the difference was statistically significant (P＜0.01). (4)NLR of SLE patients was positively correlated with CRP (rs=0.188, P=0.019), SLEDAI score (rs=0.264, P=0.001), and negatively correlated with total serum protein (rs=-0.250, P=0.002) and serum albumin (rs=-0.329, P＜0.001), respectively. (5) Multiple linear regression showed that NLR was independently associated with SLE disease activity(B=0.351, 95%CI 0.012-0.690, t=2.047, P=0.042). (6) According to ROC curve, the optimal cut-off value of NLR for SLE diagnosis was 2.17 (sensitivity 60.0%, specificity 83.1%, AUC=0.744), and the best cut-off value for predicting the activity of severe disease activity in SLE patients was 3.28 (sensitivity 58.5%, specificity 78.1%, AUC=0.700). Conclusion NLR is closely related to renal involvement, serositis and disease activity in SLE patients, which indicates that NLR, as a new inflammatory indicator, is of great significance for the assessment of SLE disease activity and organ involvement.     

Analysis and classification of B-cell infiltrates in lupus and ANCA-associated nephritis

Intrarenal B cell infiltrates resembling secondary lymphoid tissue have been found in several forms of inflammatory kidney disease. Their role in renal inflammation is not well defined, perhaps because B cell clusters have been regarded as a single entity while being quite heterogeneous. Therefore we characterized intrarenal lymphoid clusters of 32 patients diagnosed with lupus nephritis and 16 with ANCA associated nephritis. We identified four increasingly organized levels of intrarenal aggregates from scattered B cells to highly compartmentalized B cell clusters with central follicular dendritic cell networks. Most B cells displayed a mature non-antibody producing phenotype with antigen presenting ability. In regions of B cell infiltration, expression of the lymphoid chemokine BCA-1 was found in cells of a dendritic-like morphology and most B cells expressed the corresponding receptor CXCR5. Biopsies containing B cells had significantly higher levels of BCA-1 mRNA expression compared to those without, suggesting a role of BCA-1 and CXCR5 for B cell infiltration into the kidney. Our study proposes a new classification of B cell clusters in lupus and ANCA associated nephritis which might help to study the function of intrarenal B cell clusters in a more differentiated manner.     

Mesangial cell-binding anti-DNA antibodies in patients with systemic lupus erythematosus

The mechanisms by which anti-DNA antibodies contribute to the pathogenesis of lupus nephritis (LN) remain to be elucidated. This study investigates the binding of polyclonal anti-DNA immunoglobulins from patients with systemic lupus erythematosus (SLE) to human mesangial cells (HMC) in vitro. Testing of cross-sectional serum samples from 280 LN patients (108 during active disease; 172 during remission), 35 SLE patients without renal involvement, 72 patients with non-lupus primary glomerular diseases, and 37 healthy subjects with a cellular enzyme-linked immunosorbent assay showed significant IgG mesangial cell-binding activity in patients with SLE, particularly those with active LN (P < 0.0001). Significant HMC-binding activity was demonstrated in 83.9%, 42.8%, and 47.1% of patients with active LN, inactive LN, and non-renal SLE, respectively. This was predominantly attributed to binding by anti-DNA antibodies, and immune complex binding accounted for 4.6%, 3.5%, and 2.8% of seropositive samples in the respective groups. Longitudinal studies in 27 LN patients demonstrated correlation between serial levels of anti-DNA antibodies, serum HMC-binding activity, and disease activity in 18 patients (66.7%). Affinity-purified polyclonal IgG anti-DNA antibodies from sera with HMC-binding activity showed significant binding to cultured HMC, and to a lesser extent glomerular and proximal tubular epithelial cells and human umbilical vein endothelial cells, but not tumor cell lines, peritoneal mesothelial cells, bronchial epithelial cells, or fibroblasts. The binding of anti-DNA antibodies to HMC was increased 1.47-fold (P = 0.0059) after the removal of Ig-associated DNA by DNase treatment, but it was unaffected by DNase treatment of HMC membrane. Controlled trypsinization of membrane proteins in HMC resulted in a 1.26-fold (P = 0.0025) increase in their binding by anti-DNA antibodies. In conclusion, subsets of anti-DNA antibodies from patients with SLE are capable of binding to HMC. The association of such binding with renal involvement and disease activity and its modulation by DNA concentration suggest that Ig binding to HMC can be a potential marker for disease activity in selected patients and that the binding of anti-DNA antibodies to HMC may be a pathogenetic mechanism in LN.     

Anti-DNA antibodies in the urine of lupus nephritis patients.

BACKGROUND: It has previously been reported that patients with systemic lupus erythematosus (SLE) and glomerulonephritis do not have anti- (deoxyribonucleic acid) DNA antibodies in their urine. This finding was attributed to specific entrapment of anti-DNA antibodies by the immune complexes in the glomerular capillary walls. METHODS: This phenomenon has been re-investigated as part of a study of the use of desoxyribonuclease 1 (DNase 1) to treat lupus nephritis (LN). For this purpose an ELISA was developed for the detection of anti-DNA antibodies in urine. It was found that such an assay was very susceptible to the presence of DNase in urine which destroys the antigen coating the plates and gives rise to false negative results. For this reason, it is essential that all tests for anti-DNA antibodies in the urine are carried out in the presence of EDTA to inhibit the endogenous DNase 1 activity. RESULTS: Using this assay to test the urine from 24 patients with LN and non-selective proteinurea, it was found that they all contained anti-DNA antibodies. The amount of anti-DNA antibodies detected in the urine was compared with that expected by calculations from the anti-DNA antibody titre in the serum and total immunoglobulin levels in serum and in urine. It showed that in 20 patients there was neither specific entrapment nor specific excretion of anti-DNA in urine, only the expected amount of leakage. In only three patients was any appreciable entrapment demonstrated and in only one, any excess excretion. CONCLUSIONS: It is suggested that the failure to detect anti-DNA antibodies in the urine in the previous work was due to failure to inhibit the endogenous urinary DNase. It remains to be determined whether the retention of anti-DNA antibodies or excessive secretion is correlated with clinical phases of LN.     

Outcome of renal transplantation in patients with systemic lupus erythematosus

Renal transplantation is considered to be a good treatment option for patients with systemic lupus erythematosus (SLE) and end-stage renal disease. However, in patients with glomerular diseases, the outcome of renal transplantation can be adversely affected by recurrence of the original disease. Furthermore, the post-transplant course might be complicated by pre-transplant morbidity and treatment history. We studied the outcome of renal transplantation in patients with SLE who underwent transplantations in our center between 1968 and 2001. Patient and graft survival were compared with a matched control group. We specifically looked for any evidence of recurrent disease. There were 23 patients (two male, 21 female) with a mean +/-SD age of 34+/-12 years at transplantation. One patient developed renal failure with serological evidence of SLE activity at 61 months after transplantation. In the absence of urine abnormalities we favored the diagnosis of rejection, although recurrence of lupus nephritis could not formally be excluded. This was the only case of a possible recurrence of lupus nephritis. Two other patients developed extra-renal manifestations of SLE at 6 and 17 months after transplantation. Patient and graft survival rates at 5 years after transplantation were 86% and 68%, respectively. Survival rates were not significantly different from those of a matched control group, 95% and 78%, respectively. Recurrence of SLE after transplantation is rare. The results of renal transplantation in patients with SLE do not differ significantly from a matched control group. Renal transplantation is a good alternative for renal replacement therapy in patients with lupus nephritis.     

狼疮肾炎患者自噬水平及其对足细胞相关蛋白表达水平的影响

目的探讨狼疮肾炎(lupus nephritis,LN)患者自噬水平及其对足细胞相关蛋白表达水平的影响。方法选择2017年5月至2019年5月于榆林市第一医院收治的69例LN患者为LN组,50例系统性红斑狼疮(systemic lupus erythematosus,SLE)患者为SLE组,50例肾切除手术患者为对照组,观察3组肾脏足细胞内自噬体数量,比较3组肾脏组织中自噬相关蛋白、微管相关蛋白轻链3(LC3)、B淋巴细胞瘤蛋白质-2-相互作用蛋白(Beclin1)的表达,以及足细胞相关蛋白,肾病蛋白(Nephrin)、足突蛋白(Podocin)的表达。分离狼疮肾炎患者肾脏足细胞,将足细胞分为自噬抑制组和自噬诱导组,自噬抑制组加入100 nmol/L 3-甲基腺嘌呤(3-MA),自噬诱导组加入100 nmol/L雷帕霉素(RAPA),比较3组足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin等蛋白的表达。结果LN组、SLE组肾脏足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin蛋白表达量显著高于对照组(P<0.05);SLE组肾脏足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin蛋白表达量显著高于LN组(P<0.05);自噬诱导组足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin蛋白表达量显著高于正常对照组、自噬抑制组(P<0.05);正常对照组足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin蛋白表达量显著高于自噬抑制组(P<0.05)。结论LN患者自噬水平呈升高状态,自噬水平升高可能通过上调足细胞相关蛋白Podocin、Nephrin水平而减轻足细胞损伤,抑制LN病情进展。     

Association of serum renalase with disease activity in lupus nephritis

Objective To investigate the relationship between serum renalase and disease activity in lupus nephritis (LN). Methods Total of 70 patients with LN and 35 healthy volunteers admitted in Renji Hospital of Shanghai Jiao Tong University from March 2012 to March 2013 were enrolled in the study. LN patients were classified into two groups according to their systemic lupus erythematosus disease activity index (SLEDAI) scores: patients with SELDAI score lower than 8 were defined as inactive LN while others were defined as active LN. Serum samples were collected after an overnight fast and serum renalase level was determined by ELISA. Twenty active LN patients were followed up for six-months, and serum renalase was also determined before and after treatment. The differences in serum renalase level between LN patients and healthy controls were assessed, as well as the association of serum renalase with disease activity in LN. Results In 70 LN patients, 35 were classified active LN while others were inactive LN. Serum renalase level was significantly higher in LN patients than than in healthy controls (P﹤0.01). Moreover, active LN patients had higher serum renalase level compared to patients with inactive LN (P﹤0.01). Active LN patients had higher 24-hour urine protein excretion, erythrocyte sedimentation rate and anti-dsDNA antibody titers than inactive LN patients. Serum albumin was lower in inactive LN patients compared to active LN patients. There were no differences in gender, age, blood pressure and C-reactive protein between the two groups. Serum renalase levels were positively correlated with SLEDAI, 24-hour urine protein excretion, ds-DNA and ESR but inversely correlated with serum albumin and C3. Renalase amounts decreased significantly after six-months of standard therapy. The performance of renalase as a marker for diagnosis of active LN was 0.894 with a cutoff value of 66.67 mg/L. Logistic regression showed that serum renalase (OR=1.078, 95%CI 1.031-1.120, P=0.001) and complement C3 (OR=0.022, 95%CI 0.002-0.326, P=0.005) is independent indicators for disease activity in LN. Conclusions Serum renalase level was correlated with disease activity in LN. Serum renalase may serve as a potential indicator for disease activity in LN.     

De Novo Lupus Nephritis in a Renal Transplanted Child: A Case Report

De novo lupus nephritis (LN) is a rare complication in renal transplantation recipients. We present the clinical manifestations of de novo LN in a 12-year-old boy who received a cadaveric renal transplant. The cause of end-stage renal disease was prune belly syndrome with renal dysplasia. His immunosuppressive drugs included tacrolimus, mycophenolate sodium, and prednisolone. After 3 years of treatment, he developed nephrotic syndrome (NS) without other symptoms of systemic lupus erythematosus (SLE). The renal pathology of the transplanted kidney showed suspicious acute cellular rejection and LN World Health Organization class IV-G (A/C). Antinuclear antibody was positive, but anti-dsDNA and anti-Smith were negative. The serum complements were initially normal. Pulse methylprednisolone was given and the dosages of all immunosuppressive drugs increased; notwithstanding, his edema and hypoalbuminemia worsened. Repeated biopsy of the transplanted kidney was done. A full-house pattern was documented under immunofluorescent examination which confirmed LN WHO class IV-G (A/C) without evidence of rejection. He then developed macrophage-associated hemophagocytic syndrome and cytomegalovirus pneumonia. He ultimately developed pulmonary hemorrhage and died owing to severe pneumonia. De novo LN should be considered in renal transplant recipients with new onset of NS despite there not being any other clinical manifestations of SLE.