The course and treatment of lupus nephritis

Cyclophosphamide Attenuates Fibrosis in Lupus Nephritis by Regulating Mesangial Cell Cycle Progression

Objectives

Most patients with systemic lupus erythematosus (SLE) develop lupus nephritis (LN) with severe kidney manifestations. Renal fibrosis can be primarily attributed to overproliferation of mesangial cells (MCs), which are subject to drug treatment. Nevertheless, the detailed mechanisms remain elusive. We sought to identify the effect of cyclophosphamide (CTX), a drug commonly used for LN treatment, on MC proliferation and explore its underlying mechanisms. Material/Methods. Cell proliferation and fibrosis in mouse kidney tissues were determined by histopathology staining techniques. Flow cytometry was used for cell cycle analysis. Cell cycle regulators were examined in vitro following treatment of immortalized human MCs with platelet-derived growth factor subunit B (PDGF-B). Quantitative real-time PCR and western blot analyses were used to measure the mRNA and protein levels of candidate cell cycle regulators, respectively.

Results

CTX inhibited cell overproliferation induced by platelet-derived growth factor subunit B in vitro and in vivo. CTX (40 mg/l) was sufficient to induce G0/G1 phase cell cycle arrest. CTX treatment downregulated many critical cell cycle regulators including cyclins and cyclin-dependent kinases but upregulated cyclin-dependent kinase inhibitors. Additionally, CTX-treated samples showed significantly reduced fibrosis, as indicated by lower expression of interleukin-1β and α-smooth muscle actin.

Conclusion

CTX inhibits proliferation of MCs by modulating cell cycle regulator and therefore arresting them at G1 phase. CTX treatment significantly alleviates the severity of renal fibrosis. These findings provide novel insights into the mechanisms by which CTX affects LN.

Factors Associated with Renal Outcomes in an Inception Cohort of Biopsy-proven Lupus Nephritis Patients

Objective: To identify the clinical factors associated with renal response and flare in lupus nephritis (LN).

Methods: All 115 patients with biopsy-proven LN diagnosed between January 2002 and June 2015 in a tertiary centre comprised of an inception cohort that was followed up until February 2017. Baseline demographic, clinical parameters, renal biopsy histology, induction and maintenance immunosuppressive therapies, complete renal response (CRR), creatinine doubling, end-stage renal disease (ESRD), renal flares and infections were retrieved and analyzed with univariate log-rank test and multivariate Cox regression.

Results: At the time of the first renal biopsy, the age of patients was 38 ± 12.2 years (mean ± standard deviation), 90% female and systemic lupus erythematosus (SLE) disease duration 46 months (median); 67.0% were LN class IV or class IV + V. Patients were followed up for 104 ±49 months after biopsy. At months 3, 6, 12 and 24, a cumulative 25%, 46%, 66% and 76% of patients had achieved CRR, respectively. However, 49.5% who had CRR experienced [Formula: see text]1 infection of renal flare, with cumulative risk of 5%, 17%, 25% and 43% at year 1, 2, 3 and 5, respectively. Multivariate analysis showed that nephrotic syndrome ([Formula: see text] = 0.03) and delay of renal biopsy [Formula: see text]2 months from the onset of LN ([Formula: see text] ¡ 0.01) were negatively associated with CRR. Hydroxychloroquine use was beneficial in attaining CRR ([Formula: see text] = 0.03, hazard ratio = 1.70, 95% CI: 1.04, 2.80) and preventing renal flare ([Formula: see text] = 0.01, odds ratio = 0.51, 95% CI: 0.29, 0.88). By the end of the study, 80% of patients remained in CRR though 10.4% patients ended up in ESRD (all class IV), 8.7% died and 28.7% had [Formula: see text]1 infection episode requiring hospitalization.

Conclusion: Most LN patients could achieve CRR after immunosuppressive therapy but renal flares were common over time. Infective complications were fairly frequent but the incidence of ESRD was low. The use of hydroxychloroquine was associated with better renal response and fewer flares.

Urine β2-microglobulin is associated with clinical disease activity and renal involvement in female patients with systemic lupus erythematosus

Objective

We investigated the association of serum and urine β2-microglobulin (β2MG) with renal involvement and clinical disease activity in systemic lupus erythematosus (SLE).

Methods

Sixty-four female patients with SLE were enrolled. We assessed SLE disease activity (SLEDAI)-2K and measured serum and urine β2MG levels, as well as complement (C3 and C4) and anti-dsDNA levels. According to the SLEDAI scores, two groups were categorized: low (0–5 of SLEDAI) and high (6–19 of SLEDAI) disease activity groups. The presence of renal involvement was determined by renal SLEDAI score. Statistical analysis was performed using Spearman’s correlation analysis, Mann-Whitney U test, multivariate regression analysis, and logistic regression analysis.

Results

Urine β2MG levels were significantly different between low and high SLEDAI groups ( p = 0.001), but not for serum β2MG levels ( p = 0.579). Patients with renal involvement showed higher urine β2MG levels compared to those without renal involvement ( p < 0.001), but again there was not a difference in serum β2MG levels ( p = 0.228). Urine β2MG was closely associated with SLEDAI ( r = 0.363, p = 0.003), renal SLEDAI ( r = 0.479, p < 0.001), urine protein/Cr ( r = 0.416, p = 0.001), and ESR ( r = 0.347, p = 0.006), but not serum β2MG ( r = 0.245, p = 0.051). Urine β2MG level was identified as a surrogate for renal involvement ( p = 0.009, OR = 1.017, 95% CI 1.004–1.030) and overall disease activity ( p = 0.009, OR = 1.020, 95% CI 1.005–1.036).

Conclusions

We demonstrated that urine β2MG levels are associated with renal involvement and overall clinical disease activity in SLE.

Cellular and urinary microRNA alterations in NZB/W mice with hydroxychloroquine or prednisone treatment

Determining alterations to disease-associated miRNAs induced by specific therapeutics may allow the use of tailored therapy in lupus. We determined miRNA alterations in female NZB/W lupus mice treated with hydroxychloroquine (HCQ) or prednisone (PRED) for 12 weeks beginning at 24 weeks-of-age. B cell, PBMC, and urinary miR-let-7a expression were decreased with HCQ or PRED treatment. HCQ or PRED treatment reduced miR-21 expression in mesangial cells, T cells, pDCs, PBMCs, and the urine. MiR-146a expression was reduced in mesangial cells with HCQ treatment and in pDCs with HCQ or PRED treatment. PRED treatment increased miR-155 expression in mesangial, B, and T cells and PBMCs yet decreased miR-155 expression in pDCs and the urine. In vitro studies confirmed that HCQ or PRED's anti-inflammatory actions are dependent on their ability to inhibit miRNA expression. Our studies indicate that lupus therapeutics may work, in part, by altering the expression of disease-associated miRNAs.

Acquired loss of renal nuclease activity is restricted to DNaseI and is an organ-selective feature in murine lupus nephritis

An acquired loss of renal DNaseI promotes transformation of mild mesangial lupus nephritis into membranoproliferative end-stage organ disease. In this study, we analyzed expression profiles of DNaseI in other organs of lupus-prone (NZB×NZW)F1 mice during disease progression to determine whether silencing of the renal DNaseI gene is an organ-specific feature or whether loss of DNaseI reflects a systemic error in mice with sever lupus nephritis. The present results demonstrate normal or elevated levels of DNaseI mRNA and enzyme activity in liver, spleen, and serum samples from (NZB×NZW)F1 mice throughout all the stages of lupus nephritis. DNaseI activity was dramatically reduced only in kidneys of mice with sever nephritis and was the only nuclease that was down-regulated, whereas six other nucleases (DNaseII1 to 3, caspase-activated DNase, Dnase2a, and endonuclease G) were approximately normally expressed in kidneys, liver, and spleen. Loss of renal DNaseI was not accompanied by changes in serum DNaseI activity, suggesting independent mechanisms of DNaseI regulation in circulation and in kidneys and an absence of compensatory up-regulation of serum DNaseI activity in the case of renal DNaseI deficiency. Thus, silencing of renal DNaseI is a unique renal feature in membranoproliferative lupus nephritis. Determining the mechanism(s) responsible for DNaseI down-regulation might lead to the generation of new therapeutic targets to treat and prevent progressive lupus nephritis.

Reduction in glucocorticoid receptors in renal biopsies of patients with lupus nephritis

OBJECTIVES

The first-line treatment for lupus nephritis is the administration of glucocorticoids (GC) that mediate their effects via the glucocorticoid receptor (GR). The aim of this study was to investigate the expression of GR protein in the cortical area of renal parenchyma of normal and diseased renal biopsies from treated and untreated patients.

DESIGN AND METHODS

The immunohistochemical EnVision/HRP technique was performed on renal tissue to detect GR protein. Statistical analysis was performed by SAS (2001).

RESULTS

The antigen was mainly detected in glomerular podocytes and in tubules. The number of GR-positive podocytes of the controls was significantly higher than in the untreated patients, which was accordingly higher than in patients who were under medication.

CONCLUSIONS

The lower number of GR-positive cells in the diseased kidney compared to controls is possibly linked to tissue-specific GC resistance, whereas the decreased GR expression in podocytes of treated compared to untreated patients may be due to a down-regulation effect after GCs' administration.

Pharmacological therapy for Wegener's granulomatosis

Wegener's granulomatosis (WG) is the most common pulmonary granulomatous vasculitis and was a uniformly fatal disease prior to the identification of efficacious pharmacological regimens. The pathogenesis of WG remains elusive but proteinase 3-specific anti-neutrophil cytoplasmic antibodies may be involved. Histologically, WG is defined by the triad of small vessel necrotising vasculitis, 'geographic' necrosis and granulomatous inflammation. Organ involvement characteristically includes the upper and lower respiratory tracts and kidney, but virtually any organ can be involved. The severity of the disease varies, ranging from asymptomatic disease to fulminant, fatal vasculitis. Similarly, the degree of organ involvement is highly variable; WG may be limited to a single organ (typically the lungs or upper respiratory tract), or may be systemic. Currently, a regimen consisting of daily cyclophosphamide and corticosteroids, which induces complete remission in the majority of patients, is considered standard therapy. Since approximately 50% of patients experience a relapse following discontinuation of therapy, alternative regimens designed to maintain remissions after using cyclophosphamide and corticosteroids are usually necessary. This 'induction maintenance' approach to treatment has emerged as a central premise in planning therapy for patients with WG.A number of trials have evaluated the efficacy of less toxic immunosuppressants (e.g. methotrexate, azathioprine, mycophenolate mofetil) and antibacterials (i.e. cotrimoxazole [trimethoprim/sulfamethoxazole]) for treating patients with WG, resulting in the identification of effective alternative regimens to induce or maintain remissions in certain sub-populations of patients. Given the efficacy of methotrexate (for early systemic WG) and cotrimoxazole (in WG limited solely to the upper airways) to induce remissions, and the relatively decreased associated morbidity compared with cyclophosphamide, these alternative regimens are preferred in appropriate patients. Similarly, therapeutic options to maintain disease remission that are less toxic than cyclophosphamide should be offered following induction of remission unless a specific contraindication exists. By following this premise, the development of cyclophosphamide-induced morbidities (e.g. haemorrhagic cystitis, uroepithelial cancers and prolonged myelosuppression) may be minimised. Recent investigation has focussed on other immunomodulatory agents (tumour necrosis factor-alpha inhibitors [infliximab and etanercept] and anti-CD20 antibodies [rituximab]) for treating patients with WG. However, the current data are conflicting and difficult to interpret. As a result, these newer agents cannot be recommended for routine use until vigorous clinical study confirms their efficacy.

Cross-reaction of anti-DNA autoantibodies with membrane proteins of human glomerular mesangial cells in sera from patients with lupus nephritis

Anti-DNA autoantibodies were thought to play a major role in the pathogenesis of lupus nephritis (LN). A recent study revealed that affinity-purified anti-DNA antibodies had a cross-reaction with human glomerular mesangial cells (HMC). However, whether the cross-reaction was antigen-antibody-mediated was unclear. The aim of the current study was to investigate the binding of anti-DNA antibodies to HMC membrane proteins and to characterize the target antigens. Affinity-purified IgG anti-DNA antibodies were purified by DNA-cellulose chromatography in sera from nine patients with biopsy-proven active lupus nephritis. In vitro cultured primary HMCs were disrupted by sonication and HMC membranes were obtained by differential centrifugation. The membranes of human umbilical vein endothelial cells (HUVEC), human proximal renal tubular epithelial cell line (HK2) and peripheral mononuclear cells (PMC) were obtained as controls. Binding of anti-DNA antibodies to the membrane proteins was investigated by Western blot analysis using soluble membrane proteins as antigens. Both HMC membrane and affinity-purified anti-DNA antibodies were treated with DNase I to exclude DNA bridging. All nine affinity-purified anti-DNA antibodies could blot the HMC membrane proteins, and there were at least three bands at 74 kDa, 63 kDa and 42 kDa that could be blotted. Among the nine IgG preparations, all nine (100%) could blot the 74 kDa band; eight (88.9%) could recognize 63 kDa and 42 kDa protein bands separately. After DNase treatment, the same bands could still be blotted by most affinity-purified anti-DNA antibodies. Affinity-purified anti-DNA antibodies could also blot similar bands on membrane proteins of other cells, but some bands were different. In conclusion, anti-DNA autoantibodies could cross-react directly with cell membrane proteins of human glomerular mesangial cells and might play an important role in the pathogenetic mechanism in lupus nephritis.

Intensified, intermittent, low-dose intravenous cyclophosphamide together with oral alternate-day steroid therapy in lupus nephritis (long-term outcome)

The objective of this study is to evaluate the efficacy, toxicity, and long-term outcome of low-dose IV cyclophosphamid therapy with repeated frequent intervals in combination with oral and IV methylprednisolone in patients with SLE nephritis. In this study, 113 patients diagnosed as having SLE and glomerulonephritis were assessed in between 1993 and 2002, with a median follow-up of 44.1+/-41.2 months. The patients were treated with 500 mg IV cyclophosphamide and 1 g IV methylprednisolone together with 60 mg/alternate-day oral methylprednisolone in a given schedule. The clinical and laboratory data were evaluated. There were significant improvements in the clinical and the laboratory parameters. Six patients died shortly after being hospitalized due to the disease activity itself. Eight patients were excluded from the study because of low compliance. The renal functions of the patients remained stable throughout the therapy; only 16/99 patients needed one or two additional pulses. Temporary leukopenia developed in 18/99 patients and diminished with the suspension or prolongation of the IV cyclophosphamide administration. Gastrointestinal side effects, which needed extra medication, developed in 20 patients. Hematuria was observed in 6/99 patients. Menstrual abnormalities were seen in 7/99 patients. No serious infections due to immunosuppression were observed with the given regimen. Hypertension was observed in 13 patients (minimum of 140/90 mmHg, maximum of 190/110 mmHg) and controlled with angiotensine-converting enzyme inhibitors. Mild central obesity was observed in 15 of the patients. Leimyosarcoma was observed in one patient who died during the follow-up period. Therapy starting with the weekly low-dose IV cyclophosphamide to induce remission together with IV and oral steroids, followed by prolonged intervals with the same doses for 2 years, appears to be useful in preserving renal function without major side effects in patients with lupus nephritis, in comparison to other studies.

Treatment for lupus nephritis: a revisit

The optimal treatment of severe lupus nephritis remains unclear. Regimens consisting of steroid and cyclophosphamide (CYC) appear to be most effective. Infection and gonadal toxicity is a major concern of CYC use in patients of reproductive age. In addition, failure to respond or refractory to CYC treatment may lead to the development of end-stage renal disease. Mycophenolate mofetil (MMF) is a new immunosuppressive agent that selectively inhibits activated lymphocytes and renal mesangial cells. Data from experimental lupus nephritis and controlled studies, albeit small and lacking statistical power, have revealed that MMF is as effective in lupus patients as CYC in the induction of renal remission or as maintenance therapy to reduce renal flare in the short term. The significantly less ovarian toxicity and infection when compared to CYC are particularly attractive for the consideration of MMF in lupus nephritis. The potential of other new therapeutic agents is discussed together with the need for patient recruitment in future trials of lupus nephritis to address the importance of ethnicity as well as histological grading.

Predictors and outcome of renal flares after successful cyclophosphamide treatment for diffuse proliferative lupus glomerulonephritis

OBJECTIVE

To study the incidence, predictors, and outcome of renal flares after successful cyclophosphamide (CYC) treatment for diffuse proliferative glomerulonephritis (DPGN) in patients with systemic lupus erythematosus (SLE).

METHODS

Between 1988 and 2001, patients with biopsy-proven SLE DPGN who were treated initially with prednisone and CYC were studied. Those who responded to CYC were followed up for the occurrence of renal flares. The cumulative risk, predictors, and outcome of renal flares were evaluated.

RESULTS

We studied 189 patients (167 women; and 22 men) with SLE DPGN. All were initially treated with prednisone and CYC (49% orally; 51% by intravenous pulse). At the last dose of CYC, 103 patients (55%) and 52 patients (28%) had achieved complete and partial renal responses, respectively. Azathioprine (AZA) was given as maintenance therapy in 117 patients (75%). After a mean followup of 96.5 months, 59 patients (38%) experienced renal flares (42% nephritic; 58% proteinuric). The median time to relapse was 32 months. The cumulative risk of renal flare was 28% at 36 months and 44% at 60 months. Independent predictors of nephritic flares were persistently low C3 levels after CYC treatment and absence of AZA maintenance therapy. At the last clinic visit, 16 patients (10.3%) had developed doubling of the serum creatinine level (cumulative risk of creatinine doubling 7.4% at 5 years after renal biopsy and 14.3% at 10 years). Ten patients (6.5%) developed end-stage renal disease (ESRD). Renal survival rates at 5 and 10 years were 94.9% and 87.5%, respectively. Increasing histologic chronicity scores, failure to achieve complete response, persistent hypertension after CYC treatment, and nephritic renal flares were unfavorable factors for doubling of the serum creatinine level and for ESRD by univariate analysis. The occurrence of nephritic flares was the only predictor of creatinine doubling by Cox regression analysis.

CONCLUSION

In patients with SLE DPGN, renal flares are common despite initial responses to CYC. Nephritic renal flares are associated with a decline in renal function. Maintenance therapy with AZA reduces, but does not completely prevent, renal flares. More effective maintenance treatment for SLE DPGN after an initial response to CYC should be evaluated.

Mycobacteria, an environmental enhancer of lupus nephritis in a mouse model of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease characterized by the production of antibodies directed against self antigens. Immune complex glomerulonephritis (GN) is one of the most serious complications of this disorder and can lead to potentially fatal renal failure. The aetiology of SLE is complex and multifactorial, characterized by interacting environmental and genetic factors. Here we examine the nature of the renal pathology in mycobacteria-treated non-obese diabetic (NOD) mice, in order to assess its suitability as a model for studying the aetiopathogenesis of, and possible treatment options for, lupus nephritis (LN) in humans. Both global and segmental proliferative lesions, characterized by increased mesangial matrix and cellularity, were demonstrated on light microscopy, and lesions varied in severity from very mild mesangiopathic GN through to obliteration of capillary lumina and glomerular sclerosis. Mixed isotype immune complexes (IC) consisting of immunoglobulin G (IgG), IgM, IgA and complement C3c were detected using direct immunofluorescence. They were deposited in multiple sites within the glomeruli, as confirmed by electron microscopy. The GN seen in mycobacteria-treated NOD mice therefore strongly resembles the pathology seen in human LN, including mesangiopathic, mesangiocapillary and membranous subclasses of LN. The development of spontaneous mixed isotype IC in the glomeruli of some senescent NOD mice suggests that mycobacterial exposure is accelerating, rather than inducing, the development of GN in this model.

Developments in the Immunotherapy of Glomerular Disease

Glomerular diseases span a broad spectrum of clinical syndromes, with varied clinical manifestations, underlying etiologies, and pathogenic mechanisms. They can be secondary to underlying infectious, toxic, environmental, or drug exposures, or present as “primary entities.” In the latter case, most glomerular diseases are thought to be due to autoimmune dysregulation, and their treatment is primarily immunosuppressive. The armamentarium for immunomodulation includes corticosteroids, alkylating agents, anti-metabolites, calcineurin inhibitors, and new biological agents designed to block specific inflammatory pathways. The choice of therapy for an individual patient must be based on the specific character of the glomerular disease and its acuity and severity, as well as the patient’s comorbidities, history of prior exposure to immunosuppressive drugs, and risk factors for developing complications of the disease or its treatment. The complexities of such therapy can best be addressed by an experienced team of care givers in which the clinical pharmacist can help minimize, if not eliminate, potential sources of drug induced toxicities and adverse effects. This article will describe the major agents and modalities used in the management of the most common glomerular diseases.

Mycophenolate mofetil in lupus glomerulonephritis

The optimal treatment of severe lupus nephritis is unclear. Regimens consisting of steroid and cyclophosphamide (CYC) appear to be most effective. However, up to 15% of patients are refractory to CYC treatment, and 30% to 50% of patients still develop end-stage renal disease. Moreover, infection and gonadal toxicity are major concerns of CYC use in patients of the reproductive age. More effective, but less toxic, regimens are needed. Mycophenolate mofetil (MMF) is a new immunosuppressive agent that selectively inhibits activated lymphocytes and renal mesangial cells. Experience with MMF in solid-organ transplantation has shown the safety of this drug and its superiority over azathioprine (AZA) in the prevention of acute graft rejection. Data from experimental models of immune-mediated glomerulonephritis, particularly lupus nephritis, have shown that MMF ameliorates autoimmune phenomena, retards renal damage, and improves outcome. Although the use of MMF in lupus nephritis is still in its preliminary stage, uncontrolled experience has confirmed its efficacy in patients with serious disease recalcitrant to conventional cytotoxic agents. Controlled studies, albeit small and lacking statistical power, have shown that MMF is as effective as CYC in the induction of renal remission in the short term. With the current dosage used in systemic lupus erythematosus, MMF appears to be well tolerated, with no serious toxicities reported. Significantly less ovarian toxicity compared with CYC is particularly attractive for the consideration of MMF in lupus nephritis. However, the lack of long-term efficacy data and comparative studies with standard CYC regimens is the major deterrent for the first-line use of MMF in high-risk patients at this juncture.

Outcome and prognostic indicators of diffuse proliferative lupus glomerulonephritis treated with sequential oral cyclophosphamide and azathioprine

OBJECTIVE

To study the outcome and prognostic indicators of diffuse proliferative glomerulonephritis (DPGN) in patients with systemic lupus erythematosus (SLE) treated with sequential oral cyclophosphamide (CYC) and azathioprine (AZA).

METHODS

SLE patients with biopsy-proven DPGN treated with sequential oral CYC and AZA were studied. Those who achieved renal remission at 12 months were identified, and the clinical predictors of complete remission were evaluated by regression analysis. All patients were followed up until a relapse of the nephritis or a doubling of the serum creatinine level occurred. The timing and risk factors for flares and creatinine doubling were evaluated by Kaplan-Meier analysis and with the Cox proportional hazards model.

RESULTS

We studied 55 patients (47 women, 8 men; mean +/- SD age at renal biopsy 31.1 +/- 10.4 years); 25 (46%) had a serum creatinine level >106 micromoles/liter, and 29 (53%) had nephrotic syndrome. At 12 months posttreatment, 37 (67%) had complete remission and 12 (22%) had partial remission. The initial serum creatinine level was an independent predictor of complete remission. Excluding the 4 patients who were treatment- resistant or died, 21 patients (41%) had renal flares during a median followup of 4 years. The cumulative risk of renal flare was 6% at 1 year, 21% at 3 years, and 32% at 5 years. The median time to relapse was 43 months. The histologic activity score and the mean daily dose of CYC were multivariate predictors of renal flare, by Cox regression. At the last followup visit, 9 of 54 patients (17%) had a doubling of the creatinine level, 6 of whom (11%) underwent dialysis. The cumulative risk of creatinine doubling was 8.4% at 5 years and 18.2% at 10 years. An increasing chronicity index at the time of initial renal biopsy was an independent predictor of deterioration in renal function.

CONCLUSION

Sequential therapy with oral CYC followed by AZA appears to be an effective treatment regimen for DPGN in patients with SLE, with 89% of patients achieving complete or partial remission at 12 months, 62.8% remaining in remission after 5 years, and 81.8% having stable renal function after 10 years. Predictors of treatment resistance and relapse include increasing serum creatinine level, higher histologic activity scores, and a lower dose of CYC. Increasing chronicity indices predict a deterioration of renal function.

Advances in the treatment of lupus nephritis

Systemic lupus erythematosus (SLE) is an autoimmune disease that leads to the formation and deposition of immune complexes throughout the body, which are pathogenic for the disease. Different forms of glomerulonephritis can occur in patients with SLE and can contribute significantly to the associated morbidity and, ultimately, mortality from the disease. Over the past two decades, there have been significant strides in our understanding of the disease and in treatments that attempt to control the formation and deposition of anti-DNA auto-antibodies and immune complexes, as well as the subsequent inflammatory cascade mediated through various cellular and humoral pathways leading to progressive renal damage and end-stage renal disease. In this chapter, we review the current understanding of the pathogenesis and treatment of lupus nephritis in its various stages and discuss the experimental and human data regarding some of the potential newer forms of therapy. We discuss data regarding the use of steroids, azathioprine, cyclophosphamide, cyclosporine A, mycophenolate mofetil, gammaglobulin, plasmapheresis, LJP 394, flaxseed oil, bindarit, anti-CD40 ligand, and CTLA4Ig.

Lupus nephritis: lessons from experimental animal models

Lupus nephritis is a frequent and severe complication of SLE. In the last decades, animal models for SLE have been studied widely to investigate the immunopathology of this autoimmune disease because abnormalities can be studied and manipulated before clinical signs of the disease become apparent. In this review an overview is given of our current knowledge on the development of lupus nephritis, as derived from animal models, and a hypothetical pathway for the development of lupus nephritis is postulated. The relevance of the studies in experimental models in relationship with our knowledge of human SLE is discussed.

Long-term efficacy of azathioprine treatment for proliferative lupus nephritis

BACKGROUND

Combination therapy with cytotoxic drugs and corticosteroids reduces the risk for renal failure in patients with proliferative lupus nephritis (PLN), but uncertainty remains about the best mode of immunosuppression and its long-term effects. We report long-term results of combined azathioprine-prednisolone treatment for PLN, which has been the therapy of choice for the treatment of PLN at our centre for 15 yr.

PATIENTS AND METHODS

A retrospective cohort study was carried out of 26 lupus patients, seen between 1978 and 1993, with histological and/or clinical evidence of PLN. Therapy consisted of prednisolone 1 mg/kg daily, tapered after 4 weeks to the lowest possible maintenance dose combined with azathioprine up to 2.5 mg/kg. Median duration of azathioprine treatment was 53 months. Standard statistical lifetable analyses were performed.

RESULTS

Median follow-up on 1 January 1998 was 119 months. Patient survival estimates after 5, 10 and 15 yr of follow-up were 96, 91 and 82%, respectively. Four patients (15%) developed end-stage renal failure and three received renal transplants after a mean period of 27 months on haemodialysis. Renal survival estimates after 5, 10 and 15 yr of follow-up were 92, 87 and 87%, respectively. No malignancies were seen during the study period.

CONCLUSION

Azathioprine treatment for 4-1/2 yr was well tolerated in this cohort of Caucasian patients with PLN and was associated with outcomes similar to those reported for pulse cyclophosphamide therapy.

Update on cyclophosphamide for systemic lupus erythematosus

Over the past decade cyclophosphamide has come to assume an increasingly prominent role in the management of severe, life-threatening manifestations of SLE. Intermittent, intravenous pulse cyclophosphamide has become the standard of treatment of diffuse proliferative lupus nephritis (WHO Class IV), and there is now substantial clinical literature to suggest an indication for intermittent cyclophosphamide therapy in most other forms of serious lupus affecting major organ systems, in particular lupus vasculitis and acute central nervous system manifestations. This update reviews the use of cyclophosphamide in the management of lupus nephritis, expands on its role in other manifestations of SLE, and discusses potential complications of the drug.

[Treatment of lupus nephritis in children]

The severity of renal disease in systemic lupus erythematosus is variable. Renal biopsy is important to guide the treatment. The World Health Organization classification define six different histological categories with possible transformations from one category to another. Histological signs of activity or chronicity are important with respect to prognosis and treatment. Examination of renal biopsy allows predicting the reversibility of histological lesions following therapy. Apart from histological signs of severity, other factors may influence the prognosis: arterial hypertension, initial serum creatinine, the delay between onset of renal disease and treatment, the occurrence of exacerbations of the nephropathy, and the response to therapy by the end of the first year. The prognosis of severe forms of lupus nephritis, mainly diffuse proliferative glomerulonephritis, has improved during the last 20 years. The addition of immunosuppressive agents (cyclophosphamide, azathioprine) to corticosteroids is responsible for this improvement. Methylprednisolone pulses are as effective as oral high doses of prednisone during initial treatment and have fewer side effects. Many authors advocate monthly cyclophosphamide pulses over six months, sometimes followed by quarterly pulse cyclophosphamide. However, such an approach has not been proven to be more effective than an oral course of cyclophosphamide and/or azathioprine. On follow-up, steroid therapy should be slowly tapered, and close monitoring of lupus serological parameters (anti-DNA antibodies, complement), urinary protein excretion rate, urinary sediment and renal function allow one to detect exacerbations of the disease, which may require adapted therapy. While such protocols have improved the outcome, they have potential side effects. In addition to the deleterious effect of steroids on physical appearance, often badly tolerated by adolescents, immunosuppressive treatments increase the risks of severe infectious complications and the risks of cardiovascular complications in young adults.

Risk factors for hypercreatinemia in patients with systemic lupus erythematosus

Renal insufficiency is one of the most severe outcomes of systemic lupus erythematosus (SLE). The aim of this study was to identify baseline predictors of the development of renal insufficiency in a cohort of patients with SLE. 281 patients from the The Hopkins Lupus Cohort (HLC) enrolled between 1987-1994 were followed for the occurrence of renal insufficiency, defined as a serum creatinine 1.6 mg/dl for men and 1.4 mg/dl for women. Over a mean (+/-s.d.) of 3. 3+/-2.1 y of follow up, 46 (16%) of the 281 patients developed renal insufficiency. Using a multivariate Cox proportional hazard model, we found the risk of renal insufficiency associated with younger (0-19 y) or older (40 y) age at baseline (relative risk (95% CI) 5.1 (1.4, 18.8) and 4.1 (2.1, 8.2)) and longer duration of SLE before referral to the cohort (RR 1.25 [1.05, 1.5] for every five years). Additional predictive variables were borderline elevation of serum creatinine at baseline (RR 3.1 (1.4, 6.6) for a serum creatinine 1. 4-1.5 mg/dl for men and 1.2-1.3 mg/dl for women), and mean proteinuria (RR 3.6 (1.8, 7.4) for trace-3+ and 10.6 (3.8, 30.0) for 3+ (urine dipstick level)). Socioeconomic status, race, autoantibodies and complement were not significantly associated with the risk of renal insufficiency. This study supports early referral of SLE patients to rheumatologists and emphasizes the importance of early signs of renal involvement as predictors of later renal insufficiency in SLE patients.

The value of electron microscopy in the diagnosis and clinical management of lupus nephritis

The diagnosis and clinical management of patients with lupus nephritis can be a challenge from a clinicopathologic point of view. Although the majority of patients that are biopsied already have either an established clinical diagnosis or a presumptive diagnosis of systemic lupus erythematosus, determination of the immunomorphologic characteristics, pattern, and distribution of renal involvement is important for clinical management. In a clear subset of these patients with lupus nephritis, electron microscopy plays a pivotal role in accurately characterizing the type of renal involvement and determining the degree of activity, providing useful and objective guides for patients' management. Ultrastructural evaluation can also be crucial in the initial diagnosis of patients with lupus who, at the time of biopsy, lack either diagnostic clinical manifestations and/or serologic markers, and are therefore clinically unsuspected. Electron microscopic evaluation also plays a significant role in the evaluation of renal dysfunction in transplant patients with lupus nephritis, helping to determine whether recurrence of the lupus has occurred in the renal allograft. There are some ultrastructural findings that, although not pathognomonic, in the proper clinico-pathologic context are very suggestive or even diagnostic of lupus nephritis. Correlating light, immunofluorescence, and electron microscopic findings within the clinical context of lupus nephritis cases is crucial for appropriate clinical management. In some of these patients, electron microscopy provides key information that cannot be otherwise obtained.

Lupus nephritis in children

Systemic lupus erythematosus (SLE) is an autoimmune disease with varied clinical manifestations. Children and adolescents comprise one-fourth of affected patients with SLE and 40-80% of them have renal involvement. Lupus nephritis (LN) may present with mild urinary abnormalities or fulminant acute nephritis and renal failure. Diffuse proliferative glomerulonephritis (WHO class IV) is the predominant histological presentation in children and more common in boys than girls. This probably is one of the main reasons for the high mortality reported in the initial studies. Early diagnosis and aggressive treatment have led to improvement prognosis in these children. Cytotoxic therapy including intravenous cyclophosphamide has a definite role in the management WHO class IV and occasionally class III lupus nephritis. Prolonged steroid and cytotoxic therapy may lead to significant toxicity.

Immunosuppressive therapy of lupus nephritis

Aggressive immunosuppressive therapy should be considered for patients with proliferative lupus nephritis as the risk for progression to end stage renal disease is high. Intermittent intravenous cyclophosphamide therapy improves renal survival; longer duration of therapy is associated with fewer relapse of nephritis and decreased risk of diminished renal function. While azathioprine therapy does not differ statistically from steroids alone in prolonging renal survival, this therapy may be considered in patients with few risk factors for progression to renal insufficiency. Methylprednisolone as a single therapy does not prolong renal survival compared with regimens including cyclophosphamide. Plasmapheresis remains under study but has not shown additional benefit in treatment of severe lupus nephritis. The potential roles for cyclosporin A and mycophenylate mofetil in the therapy of proliferative lupus nephritis remain to be defined. Supportive care including rigorous control of hypertension, consideration of angiotensin receptor inhibition or blockade to reduce proteinuria and prolong renal function, control of hyperlipidemia, prevention of osteoporosis, and prevention of pregnancy remain important clinical goals. Current research efforts focus on genetic and socioeconomic factors involved in racial differences in expression of lupus nephritis, hormonal manipulation to preserve gonadal function during cyclophosphamide therapy, and the potential impact on lupus activity of estrogen-containing oral contraceptives or postmenopausal hormone replacement therapy.

Indications for, and use of, cytotoxic agents in SLE

Over the past decade, cytotoxic drugs have come to assume an increasingly important role in the management of systemic lupus erythematosus. Intravenous cyclophosphamide has become the standard treatment for lupus affecting major organs, in particular lupus nephritis. Cytotoxics with less potential for adverse side effects such as azathioprine and methotrexate are widely used in the management of non-major organ lupus and as an adjunct to reduce corticosteroid requirements. Recent clinical experience in lupus with newer cytotoxic drugs such as cyclosporin A, adenosine analogues, and mycophenolate mofetil appear promising and may offer improvements in lupus management in the future.

Therapeutic plasmapheresis

Plasmapheresis is the process by which plasma containing components causing or thought to cause disease is removed from the circulation, and the remaining blood components are returned with plasma or a harmless plasma substitute to the donor. It primarily removes protein-bound solutes or high-molecular-weight solutes such as circulating protein-bound toxins, autoantibodies, immune complexes, or other abnormally occurring molecules. Plasmapheresis has been used in the treatment of more than 100 diseases in human medicine, including immune-mediated diseases, neoplasia, infectious diseases, sepsis, hyperlipidemia, thyrotoxicosis, and removal of toxins. In immune-mediated disease, it is most useful to rapidly decrease plasma concentrations of antibodies or immune complexes, whereas other immunosuppressive measures are used to prolong the effect.

Immune ablation and hematopoietic stem cell rescue for severe autoimmune diseases (SADS)

In addition to our center (Northwestern University, Chicago), several institutions in the United States (Fred Hutchinson Cancer Center, University of California at Los Angeles, and Medical College of Wisconsin) and Europe are activating protocols to transplant patients with SADS. In this age of cost-effectiveness, it will be difficult to arrange third-party reimbursement for a hematopoietic stem cell transplant that may lead to medical charges of between $100,000 and $200,000. However, the cost of standard medical care for patients with SADS is not trivial. Dialysis for an SLE patient with renal failure costs $40,000 per year, while the medical resources required to care for a patient with progressive multiple sclerosis may exceed $35,000 per year. Unique BMT regimen-related toxicities may occur, including intracranial hemorrhage in the SLE or rheumatoid arthritis patient who has vasculitis; acute neurologic decompensation in patients with multiple sclerosis, especially if the conditioning regimen contains neurotoxic agents that cross a compromised blood-brain barrier; respiratory failure in patients with myasthenia gravis; and increased renal or pulmonary toxicity in patients with scleroderma and parenchymal fibrosis. Scleroderma-associated gastrointestinal dysmotility and bacterial overgrowth may also lead to greater fungal and bacterial infections [76]. BMT is currently considered appropriate therapy for patients with chronic-phase Chronic myelogenous leukemia (CML) and indolent lymphomas who otherwise have a relatively long life expectancy of 5 and 10 years, respectively. The roughly similar long survival but greater functional impairment of patients with SADS may justify consideration of immune ablation and hematopoietic stem cell rescue.