Subcutaneous and intravenous belimumab in the treatment of systemic lupus erythematosus: a review of data on subcutaneous and intravenous administration

Introduction: Loss of B cell tolerance is a hallmark feature of the pathogenesis of Systemic Lupus Erythematosus (SLE). Recent advances in B cell therapy have focused on targeted therapy aimed at inhibiting B cell activation and reducing B cell survival. Belimumab, a human monoclonal antibody against B cell activating factor (BAFF) was licensed in 2011 for the treatment of SLE.

Areas covered: We review the data on the intravenous and subcutaneous formulations of belimumab in the management of patients with SLE. BLISS-52 and BLISS-76 demonstrated the efficacy of intravenous belimumab (10mg/kg) as an add-on therapy in SLE patients with active disease. A recent phase III trial of intravenous belimumab reported similar results in North East Asian patients. Subcutaneous belimumab (200mg/weekly) has demonstrated similar efficacy, safety and tolerability and was approved by the FDA in 2017 for the treatment of active autoantibody positive SLE patients receiving standard therapy.

Expert commentary: Belimumab is generally safe and well tolerated. The most common clinical manifestations of SLE in the clinical trials were arthritis, mucocutaneous disease and serositis. Patients with severe lupus nephritis and central nervous system disease were excluded from these clinical trials.     

B-Cell Targeted Therapies in Systemic Lupus Erythematosus

Systemic lupus erythematosus is a multisystem autoimmune disease characterized by the formation of autoantibodies that target a variety of self antigens. B cells are fundamental to the development of these antibodies and are a target for intervention in the disease. This review discusses four therapies that target B cells by inducing B-cell depletion, reduction in B-cell proliferation and differentiation, or modulation of B-cell function. Rituximab is an anti-CD20 chimeric monoclonal antibody that depletes B cells but not plasma cells. Systematic reviews of open label studies, particularly in lupus patients refractory to conventional therapy, have suggested that rituximab can be an effective treatment for non-renal lupus and lupus nephritis. However, randomized, double-blind, controlled trials comparing rituximab with placebo in addition to standard of care therapy for non-renal lupus and lupus nephritis over 12 months failed to demonstrate efficacy using the planned primary endpoints, although there were some post-hoc analyses suggesting that rituximab may have beneficial effects that would be worthy of further study as no significant toxicity has been demonstrated. Treatment with belimumab, a humanized monoclonal antibody targeted against B lymphocyte stimulator (BLys), was more efficacious than placebo and had no significant increase in adverse events in two non-renal, phase III lupus trials when given in addition to standard of care therapy for 52 weeks. Belimumab is licensed for the management of lupus in the US and in Europe. Atacicept is a humanized fusion protein that binds BLys and APRIL (a proliferation-inducing ligand) that might be more effective than belimumab in the management of lupus. Unfortunately a phase II/III trial of atacicept in lupus nephritis had to be stopped due to the development of low immunoglobulin levels and pneumonias in some patients. However, in retrospect these complications may have been due to concomitant treatment with mycophenolate mofetil and results of a 52-week, non-renal, phase III trial with atacicept are awaited. Epratuzumab is a humanized monoclonal antibody that targets CD22 on B cells and results in modulation of B-cell function and migration, as CD22 regulates adhesion and inhibits B-cell receptor (BCR) signalling. Epratuzumab at a cumulative dose of 2,400 mg over 4 weeks has been shown to improve lupus disease activity compared with placebo 12 weeks after initiation of therapy in a phase II study, and a 12-month phase III study is on-going. B-cell targeted therapies are an attractive prospect for treating lupus disease and the results of current phase III trials are eagerly awaited. Finding the most appropriate trial design to demonstrate efficacy in lupus trials has been a challenge. The SRI (SLE response index) used in the belimumab studies and the BICLA (British Isles Lupus Assessment Group-based Composite Lupus Assessment) used in the epratuzumab studies are currently the promising trial designs for non-renal studies. For lupus nephritis it is important that trials are of adequate duration to be able to demonstrate benefit of new therapies over conventional therapy.     

Belimumab: A Guide to Its Use in Systemic Lupus Erythematosus

Belimumab (Benlysta?), a fully human recombinant IgG1λ monoclonal antibody that inhibits the binding of soluble B lymphocyte stimulator to B cells, is indicated for the treatment of adult patients with active, autoantibody-positive systemic lupus erythematosus (SLE) with a high degree of disease activity despite receiving standard therapy. In multinational trials, significantly more belimumab recipients than placebo recipients achieved an SLE Responder Index response at 52 weeks.     

Belimumab Therapy in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex heterogeneous disease, posing challenges to clinical trials. As in other autoimmune diseases, B-lymphocytes play a central role in lupus pathogenesis. The finding that selection and survival of B cells are controlled by a variety of signals, including those provided by the longevity factor BAFF (B-cell activating factor), also called BLyS (B-lymphocyte stimulator), led to preclinical trials that revealed that BAFF represents a promising therapeutic target for human lupus. Belimumab is a fully human monoclonal antibody directed against BAFF. Lessons learned from early clinical trials led to improved methods and success of phase III trials, with recruitment of patients with both clinically and serologically active disease, development and use of a novel SLE Responder Index, and progressive and special restrictions on immunosuppressive and corticosteroid use. These studies offer an attractive blueprint to conduct future clinical trials in SLE. The overall steroid-sparing ability and benefits of belimumab on musculoskeletal and mucocutaneous organ systems suggest that it has an impact on the clinical management of SLE patients. Future directions include studies to determine the role of belimumab in early SLE, as well as in renal or CNS involvement.     

Cyclosporin

Systemic lupus erythematosus (SLE) is a complex multisystem disease which is characterised by formation of antibodies to ;self' antigens. It often presents as a mild, controllable disorder but may become severe and is potentially life threatening, particularly when major organs/systems are involved. Although treatments for severe SLE are available (e.g. corticosteroids +/- cytotoxic/immunosuppressive agents), high dose or long term therapy with these agents is associated with serious and potentially life-threatening adverse effects and is not effective in all patients. Several noncomparative trials in patients with severe SLE refractory to conventional treatment have demonstrated that low dose cyclosporin in combination with steroids (and occasionally with additional cytotoxic/immunosuppressive agents) can provide long term disease improvement or remission and, importantly, a reduction in steroid use. Clinical benefits have also been observed with the cyclosporin-steroid combination in patients with lupus nephritis, most of whom had failed to respond to conventional treatment. Nephrotoxicity has been documented in some patients receiving cyclosporin for SLE, but initial biopsy data suggest that this complication is not a treatment-limiting factor for most patients. Nevertheless, the risk of cyclosporin-induced nephrotoxicity and the clinical implications of this effect have yet to be accurately assessed in large numbers of patients with SLE and definitive data may be difficult to obtain. Although initial efficacy and tolerability data from patients with lupus nephritis are favourable, the drug is more likely to be used in patients whose kidney function remains relatively unimpaired. Thus, available noncomparative data suggest that cyclosporin is useful in the treatment of patients with severe refractory SLE or those who cannot tolerate conventional therapy, but definitive comparative data are lacking. Any decision to prescribe cyclosporin for such patients will need to take into account the potential benefits of the drug, the clinical implications of uncontrolled disease and the risk of nephrotoxicity in individual patients.     

B-Cell-Targeted Therapy for Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a classic autoimmune disease characterized by a myriad of immune system aberrations, most likely resulting from pathogenic autoantibody production, immune complex deposition, and subsequent end-organ damage. B cells play a key role in the pathogenesis; therefore, B-cell-targeted therapies, including B-cell depletion and blockage of B-cell survival factors such as B-lymphocyte stimulator (BLyS), are potential therapeutic targets for SLE. In uncontrolled clinical trials from approximately 20 studies, rituximab--a mouse-human chimeric anti-CD20 monoclonal antibody that effectively depletes B cells--has been demonstrated to reduce disease activity and decrease serum autoantibodies, with a clinical response of 86% in a case series of approximately 400 SLE patients with refractory disease, with or without concomitant use of cyclophosphamide. Epratuzumab, a humanized anti-CD22 monoclonal antibody that partially depletes B cells, has also been shown to reduce disease activity but not to decrease autoantibody levels in patients with moderately active SLE. Randomized controlled phase I/II trials in patients with active SLE have documented that belimumab, a humanized anti-BLyS monoclonal antibody, reduces B-cell numbers, inhibits disease activity and decreases anti-double-stranded DNA autoantibody in SLE patients. All these therapies are well tolerated, but accompanying infectious complications have been observed. Other B-cell-targeted therapies such as 'humanized' monoclonal antibodies to CD20 (e.g. ocrelizumab) and agents that interrupt B-cell/T-cell interactions also have potential, and the efficacy of these, along with rituximab, belimumab and epratuzumab, needs to be determined by randomized controlled trials.     

Clinical usefulness of the Crithida luciliae test for antibodies to native DNA.

The Crithidia luciliae assay (CL-IF) for antibodies to native DNA was found to be significantly more sensitive and specific for systemic lupus erythematosus (SLE) than the Farr radioimmunoassay (RIA). High titers of antibodies to native DNA were seen exclusively in patients wtih SLE using the CL-IF test. The titers correlated with the activity of SLE and nephritis, in that the highest titers occurred in patients with active disease and severe nephritis, the lowest in patients with inactive lupus and normal renal function. Favorable responses to therapy were associated with decreases in CL-IF titers. The CL-IF assay can detect complement-fixing antibodies to native DNA. Their presence correlated with the disease activity and nephritis in SLE patients. The simple and inexpensive CL-IF test could either replace the RIA in clinical laboratories or be used in conjunction with the RIA as a confirmatory test for antibodies to native DNA.     

Therapeutic effect of retinoic acid in lupus nephritis

Lupus nephritis is a major cause of morbidity and mortality among patients with systemic lupus erythematosus (SLE). In these patients, treatment with immunosuppressive agents can significantly improve the outcome of lupus nephritis. However, these agents have severe adverse reactions and some patients are refractory to those therapies. Retinoids, a group of natural and synthetic derivatives of vitamin A, play important regulatory roles of cellular proliferation, differentiation and apoptosis. They have been used for the treatment of acute promyelocytic leukemia and inflammatory disorders such as psoriasis and acne. It has also been shown that retinoids have therapeutic effects in various animal models of kidney disease, including lupus nephritis. Based on these findings, retinoids are a promising agent for the treatment of lupus nephritis. We studied the clinical effects of retinoid therapy in patients with lupus nephritis. In open clinical trial, 7 patients with active lupus nephritis that was refractory to steroid therapy were studied. In all these patients, retinoid was added to the immunosuppressive therapy and its therapeutic effects were evaluated. As a result, 4 out of 7 patients showed improvement of the clinical symptoms and laboratory findings, including urinary protein and anti-dsDNA antibody levels. No important adverse effects of ATRA therapy were observed in all patients. Thus, retinoids might be indicated in cases of lupus nephritis that are refractory to conventional immunosuppressive therapy.     

Intravenous immunoglobulin therapy and systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with diverse manifestations. We suggest that intravenous immunoglobulin (IVIg) therapy may be beneficial and safe for various manifestations in SLE. A structured literature search of articles published on the efficacy of IVIg in the treatment of SLE between 1983 and 2005 was conducted. We searched the terms “IVIg,” “intravenous immunoglobulin,” “lupus,” “SLE,” and “systemic lupus erythematosus.” The various clinical manifestations of SLE that were reported to be successfully treated by IVIg in case reports include autoimmune hemolytic anemia, acquired factor VIII inhibitors, acquired von Willebrand disease, pure red cell aplasia, thrombocytopenia, pancytopenia, myelofibrosis, pneumonitis, pleural effusion, pericarditis, myocarditis, cardiogenic shock, nephritis, end-stage renal disease, encephalitis, neuropsychiatric lupus, psychosis, peripheral neuropathy, polyradiculoneuropathy, and vasculitis. The most extensive experience is with lupus nephritis. There are only a few case series of IVIg use in patients with SLE with various manifestations, in which the response rate to IVIg therapy ranged from 33 to 100%. We suggest that IVIg devoid of sucrose, at a dose of 2 g/kg over a 5-d period given uniformly and at a slow infusion rate in patients without an increased risk for thromboembolic events or renal failure, is a safe and beneficial adjunct therapy for cases of SLE that are resistant to or refuse conventional treatment. The duration of therapy is yet to be established. Controlled trials are warranted.     

Belimumab and antipneumococcal vaccination in patients with systemic lupus erythematosus

In systemic lupus erythematosus (SLE), flares can be caused by infections. In particular, Streptococcus pneumoniae infection can be severe or even potentially lethal in absence of previous immunization or in case of ‘aggressive’ systemic antibiotic therapy. Immunization efficacy, however, can be reduced in such patients with the use of the various immunosuppressive therapeutic regimens. In particular, the use of novel monoclonal antibodies against B lymphocytes raises concerns over the potential interference with antipneumococcal vaccination. Previous studies demonstrated that belimumab therapy did not significantly reduce the efficacy of antipneumococcal vaccination, when received after the initiation of belimumab therapy. The study being evaluated in this article investigated the efficacy of vaccination in relationship to initiation of belimumab therapy in SLE patients.     

Epratuzumab for the treatment of systemic lupus erythematosus

Introduction: Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease. There are three drugs licensed for the treatment of lupus: corticosteroids, hydroxychloroquine and belimumab. Immunosuppressants such as azathioprine, methotrexate and mycophenolate are also used. Despite these treatments there is still considerable morbidity. New treatments are needed for the management of active lupus. Epratuzumab a humanized IgG1 monoclonal antibody that targets CD22 resulting in selective B cell modulation that has been considered a potential treatment for SLE.

Areas covered: Summary of the relevant pathogenesis and disease activity measurements used in SLE patients, current treatments and unmet needs in SLE, pharmacokinetics and pharmacodynamics of epratuzumab therapy, and a summary of the 7 clinical trials that have investigated the efficacy and safety of epratuzumab in SLE.

Expert commentary: It is not clear why trials have failed to demonstrate efficacy but high placebo response rates from optimisation of standard of care and a sub-optimal dosing regimen may have played a role. Post-hoc analysis suggested that there may be subgroups that did respond, such as anti-SSA positive patients with features of Sjogren’s syndrome. Further research is needed to explore this and other potential sub-groups that might respond.     

Unmet Needs in the Pathogenesis and Treatment of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune rheumatic disease with a prevalence of approximately 1 in 1000. Over the last 30 years, advances in treatment such as use of corticosteroids and immunosuppressants have improved life expectancy and quality of life for patients with lupus and the key unmet needs have therefore changed. With the reduced mortality from disease activity, development of cardiovascular disease (CVD) has become an increasingly important cause of death in patients with SLE. The increased CVD risk in these patients is partly, but not fully explained by standard risk factors, and abnormalities in the immune response to lipids may play a role. Invariant natural killer T cells, which are triggered specifically by lipid antigens, may protect against progression of subclinical atherosclerosis. However, currently our recommendation is that clinicians should focus on optimal management of standard CVD risk factors such as smoking, blood pressure and lipid levels. Fatigue is one of the most common and most limiting symptoms suffered by patients with SLE. The cause of fatigue is multifactorial and disease activity does not explain this symptom. Consequently, therapies directed towards reducing inflammation and disease activity do not reliably reduce fatigue and new approaches are needed. Currently, we recommend asking about sleep pattern, optimising pain relief and excluding other causes of fatigue such as anaemia and metabolic disturbances. For the subgroup of patients whose disease activity is not fully controlled by standard treatment regimes, a range of different biologic agents have been proposed and subjected to clinical trials. Many of these trials have given disappointing results, though belimumab, which targets B lymphocytes, did meet its primary endpoint. New biologics targeting B cells, T cells or cytokines (especially interferon) are still going through trials raising the hope that novel therapies for patients with refractory SLE may be available soon.     

Rituximab: a promising therapy in systemic lupus erythematosus

Several trials of new immunologic agents in systemic lupus erythematosus (SLE) have recently been undertaken. Rituximab, a chimeric antibody directed against CD20 on B lymphocytes, has emerged as a promising therapy. Based upon preliminary data, clinical efficacy of rituximab has been documented in both pediatric and adult-onset SLE patients. The specific manifestations reported to be beneficially affected include lupus nephritis, arthralgia/arthritis, serositis, cutaneous vasculitis, mucositis, rashes, fatigue and neurologic symptoms. Although rituximab's mechanisms of action are incompletely understood, the effects of rituximab are likely mediated by antibody-dependent cell-mediated cytotoxicity and the induction of apoptosis. The resultant repopulation of B cells, alteration of abnormal B cell homeostasis and down-regulation of co-stimulatory molecules on both B and T cells all likely contribute to clinical efficacy. Good tolerability of rituximab is reported with rare serious side effects. The positive response to rituximab verifies a central role for B cells in SLE. This article highlights the clinical experience of rituximab therapy in both pediatric and adult-onset SLE. These data suggest a promising role for rituximab in the treatment of SLE. Further controlled trials and long-term outcome studies are imperative to further define its clinical application and to improve the care of patients.     

Belimumab Efficacy is ‘Mild’ but Market Potential Still Great

Speaking for the inThought Expert Discussion Series in February, Dr George Tsokos mirrored the opinion of many lupus thought leaders: Human Genome Sciences (HGS) and GlaxoSmithKline’s (GSK) belimumab (Benlysta®) was likely to be approved by the US FDA and, despite modest efficacy, will be used by a large proportion of lupus patients. Dr Tsokos praised HGS and GSK’s clinical trial program for belimumab, noting that huge trials and unique trial endpoints were needed to demonstrate the drug’s efficacy, allowing it to succeed where so many other lupus drugs have failed. Still, belimumab’s trial design may not become standard in future lupus trials — questions about identification of appropriate lupus patients with active disease, trial endpoints, and subgrouping lupus patients remain. Although Dr Tsokos does not expect other agents currently being tested in lupus trials to be significantly more efficacious than belimumab, his research suggests that significantly better results could be obtained using agents targeting interleukin-17, spleen tyrosine kinase (SYK), and calcium/calmodulin-dependent protein kinase type IV (CaMKIV). In line with Dr Tsokos’ comments and consistent with inThought’s outlook for belimumab, the US FDA granted approval for belimumab in March 2011, making it the first new lupus drug to be approved in more than 50 years. inThought projects US sales of $1.1 billion for belimumab by 2017.     

Th1/Th2 balance of SLE patients with lupus nephritis

Systemic lupus erythematosus (SLE) is a prototypic systemic autoimmune disease that is characterized by the production of multiple autoantibodies and immune complex formation. Lupus nephritis, which has various histological patterns and variable clinical outcomes, is one of the most important complications of SLE. Although this pathogenetic mechanism in each histologically different type of nephritis remains unclear, recent findings in murine lupus elucidate an essential role for the Th1 cytokine in the development of diffuse lupus nephritis (DLN), and Th2 cytokine in that of membranous lupus nephritis (MLN). These data support the hypothesis that individual Th1/Th2 balance is one of the critical determinants for histopathology of lupus nephritis. Therefore the value of Th1/Th2 ratio of the peripheral CD4+ T cells in SLE patients could be a useful index to predict histopathology of lupus nephritis.     

Successful treatment of refractory thrombocytopenia with mycophenolate mofetil in a patient with systemic lupus erythematosus

While mild thrombocytopenia in systemic lupus erythematosus (SLE) is frequently seen in the context of active disease, severe thrombocytopenia causing significant bleeding is not that common. Corticosteroids are considered the first line therapy for severe thrombocytopenia in SLE. Second-line therapeutic agents or splenectomy have been reported to be effective for patients who fail to respond to steroids or those who require moderate doses of steroids to maintain the platelet counts. Recent randomized controlled studies have shown that mycophenolate mofetil (MMF) is an efficacious and safe therapeutic agent in patients with proliferative forms of lupus nephritis. However, little information has been available regarding the role of MMF in the treatment of immune thrombocytopenia complicated with SLE. Hereby I describe a patient with SLE in whom thrombocytopenia was refractory to corticosteroids, intermittent intravenous cyclophosphamide, azathioprine, cyclosporine, intravenous gamma globulin, danazol, and splenectomy, and whose platelet counts eventually normalized during therapy with MMF. In this patient, thrombocytopenia is initially thought to be associated with active SLE involving major organ. However, after immunosuppressive agents were given, the refractory nature of thrombocytopenia seems to be an isolated phenomenon, independently of SLE activity.     

Therapeutic blockade of TNF in patients with SLE-promising or crazy?

TNF is an important mediator of inflammation, but is also involved in the control of autoimmunity. The latter has been demonstrated in a murine model of SLE (NZB/W) and by the occurrence of autoantibodies to nuclear antigens as well as occasional, transient lupus-like syndromes in patients under TNF blockade. In contrast, data on increased TNF levels in serum, kidney and skin samples of SLE patients as well as results in other mouse models of the disease point to an inflammatory role of TNF in SLE organ disease. Despite all due caution, given these two sides of the cytokine, TNF blockade has by now been employed for several years in single cases and open label studies; data on more than fifty patients have meanwhile been published, for the vast majority of which infliximab was employed. These clinical data have to be very cautiously interpreted, as always with data on single cases or open label trials. However, some consistent pieces of information emerge and may inform controlled clinical trials: (i) While antibodies to double-stranded DNA commonly showed transient increases, lupus flares have not been seen so far and thus apparently are at least not the rule; (ii) in contrast, increases in anti-phospholipid antibodies may be associated with vascular adverse events; (iii) bacterial infections, pneumonia and urinary tract infections in particular, have been observed; (iv) short term induction therapy appears relatively safe, while long-term TNF blockade may confer significant risks in SLE; (v) TNF blocker induction therapy may lead to long-term remission in patients with lupus nephritis, hemophagocytic syndrome, and interstitial lung disease; (vi) patients with lupus arthritis often respond to TNF-blockade but symptoms recur after cessation of therapy, necessitating longer term therapy, which is more risky than short term treatment.     

Intravenous immunoglobulin for immunomodulation of systemic lupus erythematosus

Intravenous immunoglobulin (IVIg) is used for replacement therapy in immunodeficiency states and for immunomodulation of various autoimmune diseases. Several case reports and series support a beneficial role of IVIg in systemic lupus erythematosus (SLE), both as salvage immunotherapy and in control of disease activity in general and amelioration of classical disease manifestations. Further, lupus nephritis can also be treated usually successfully with IVIg. A few questions remain unanswered as to the appropriate therapeutic dosage and the clinical manifestations that can be best treated with IVIg.     

Biological and targeted therapies of systemic lupus erythematosus: evidence and the state of the art

Introduction: Systemic lupus erythematosus (SLE) is a multi-systemic disease characterized by an unpredictable disease course and periods of remission and flare, leading to organ damage and mortality. Novel biological agents are being developed (targeting the lymphocytes, accessory molecules and cytokines) that aim to enhance the therapeutic efficacy when combined with standard therapies.

Areas covered: This article updates recent data on the use of biological and targeted therapies in SLE.

Expert commentary: B cells remain the main target of development of novel therapeutics in SLE. Similar to the intravenous preparation, subcutaneous belimumab has been shown to be superior to placebo when added to the standard of care in SLE. However, two phase III trials of epratuzumab and blisibimod did not meet their primary endpoints. Recent data on the inhibition of type I interferons (anifrolumab) appear promising. Newer calcineurin inhibitors and combination strategies using conventional immunosuppressive agents are being tested in lupus nephritis. Finally, international groups are developing consensus definitions on disease remission and low disease activity state to explore the benefits of the treat-to-target strategy in SLE. Hopefully, the armamentarium for the treatment of SLE can be expanded in the near future, so that the longevity and quality of life of patients can be further improved.     

Autoantibodies against monomeric C-reactive protein in sera from patients with lupus nephritis are associated with disease activity and renal tubulointerstitial lesions

Serum levels of C-reactive protein (CRP) often remain low despite high disease activity in systemic lupus erythematosus (SLE). Sera from 96 patients with renal biopsy-proven active lupus nephritis, 24 of 96 patients in remission, and 49 patients with SLE with negative urinalysis (nonrenal SLE) was collected. Immunoglobulin G autoantibodies against monomeric CRP (mCRP) were screened by enzyme-linked immunosorbent assay with purified human CRP. Associations with clinical features, pathological data, and laboratory findings were investigated. The prevalence of mCRP autoantibodies in active lupus nephritis (57/96, 59.4%) was significantly higher than that in patients with SLE without clinical evidence of kidney involvement (20/49, 40.8%, p = 0.034). For the 13 patients with positive mCRP autoantibodies and sequential sera, their positive mCRP autoantibodies in active phase turned negative in remission (13/13, 100%). Patients with mCRP autoantibodies had significantly higher SLEDAI scores than patients without mCRP autoantibodies (18.3 +/- 5.2 vs 15.8 +/- 4.0, p = 0.013), who were more likely to experience acute renal failure (14/55 vs 2/33, p = 0.022), oral ulcer (15/57 vs 3/39, p = 0.022), and delayed activated partial thromboplastin time (18/52 vs 2/38, p = 0.001). Positive correlations between levels of mCRP autoantibodies and semiquantitative scores of renal histologic features were first observed in lupus nephritis as follows: interstitial inflammation (r = 0.328), tubular atrophy(r = 0.276), interstitial fibrosis (r = 0.211), and chronicity index score (r = 0.243). Autoantibodies against mCRP are prevalent in patients with lupus nephritis and are associated with disease activity and renal tubulointerstitial lesions.