Management of Pediatric Systemic Lupus Erythematosus: Focus on Belimumab.

Belimumab (Benlysta®) is a fully humanized monoclonal antibody that inhibits B lymphocyte stimulator (BLyS, also known as B cell-activating factor of the tumor necrosis factor family) and was approved by the US Food and Drug Administration (FDA) and the European Medicines Evaluation Agency for the treatment of autoantibody-positive systemic lupus erythematosus (SLE) in adults with moderate disease activity. Belimumab was recently FDA approved for use in children with SLE between 5 and 17 years of age. This review discusses the key findings of the belimumab phase III trials in adult SLE (via intravenous and subcutaneous administrations), phase II trial in pediatric SLE (intravenous administration), and post hoc analyses. It also evaluates the current clinical trials of belimumab in specific SLE disease states and highlights the safety profile of belimumab. It discusses the clinical post-marketing use of belimumab in adults and children with SLE and concludes with our recommendations for the use of belimumab to treat pediatric SLE, including a look to the future with increased real-world use in children with SLE.

Prevalence of progressive multifocal leukoencephalopathy (PML) in adults and children with systemic lupus erythematosus.

OBJECTIVE: To define the risk of progressive multifocal leukoencephalopathy (PML) in SLE. METHODS: This is a retrospective observational study to evaluate PML cases in patients with SLE admitted to two large academic hospitals. Using electronic medical record (EMR) data, International Classification of Diseases (ICD) codes identified PML cases among patients with SLE, rheumatoid arthritis (RA) (controls), had renal transplant and with HIV. Medication exposure was reviewed. RESULTS: A total of 5409 Columbia University Medical Center (CUMC) patients and 2046 Northwell Health patients were identified using one ICD code for SLE. Of 7455 patients, three had an ICD code for PML. On EMR review, however, PML was substantiated in only one fatal SLE case with significant immunosuppressant use and severe lymphopenia (<0.5 cells x 109/L); one patient was evaluated for PML but cerebrospinal fluid (CSF) was negative for JC virus and improved with treatment of central nervous system (CNS) lupus. EMR data were very limited for the third patient and diagnosis could not be confirmed. None of the 13 342 patients with RA ICD codes had PML. Of the 5409 patients with an SLE ICD code at CUMC, 212 also had a renal transplant ICD code, and 83 had concomitant HIV/AIDS. Based on inpatient pharmacy records of 5409 hospitalised patients at CUMC, 59.2% were treated with steroids, and 16.09% with immunosuppressants (7.76% mycophenolate, 3.42% cyclophosphamide, 2.88% azathioprine and 2.03% rituximab). No patients with paediatric SLE (pSLE) (n=538) had PML. The combined prevalence of PML in hospitalised patients with SLE at the two hospitals was 13-27/100 000 patients. CONCLUSION: Among 7455 adult patients with SLE ICD codes, there were two PML cases, with only one confirmed case associated with severe lymphopenia and immunosuppressants, corresponding to a prevalence of 13-27 per 100 000 patients. No PML cases in pSLE were found. A high index of suspicion in patients with SLE and CNS manifestations is required for the prompt diagnosis of PML.

Belimumab in systemic lupus erythematosus: a perspective review.

Belimumab (Benlysta(®)) is a fully humanized monoclonal antibody that inhibits B-lymphocyte stimulator (also known as B cell activating factor of the tumor necrosis factor family) and was approved by the US Food and Drug Administration and the European Medicines Evaluation Agency for treatment of autoantibody-positive systemic lupus erythematosus (SLE) in adults. This review discusses the key findings of the phase III trials, post hoc analyses, and real-world postmarketing use of belimumab in the routine care of SLE patients. It also highlights the safety profile of belimumab and gives insight into its potential use to treat childhood-onset SLE. It concludes with a discussion of the current clinical trials investigating belimumab in specific SLE disease states and a look to the future with novel targeted B-cell therapies.

STAT3 interrupts ATR-Chk1 signaling to allow oncovirus-mediated cell proliferation.

DNA damage response (DDR) is a signaling network that senses DNA damage and activates response pathways to coordinate cell-cycle progression and DNA repair. Thus, DDR is critical for maintenance of genome stability, and presents a powerful defense against tumorigenesis. Therefore, to drive cell-proliferation and transformation, viral and cellular oncogenes need to circumvent DDR-induced cell-cycle checkpoints. Unlike in hereditary cancers, mechanisms that attenuate DDR and disrupt cell-cycle checkpoints in sporadic cancers are not well understood. Using Epstein-Barr virus (EBV) as a source of oncogenes, we have previously shown that EBV-driven cell proliferation requires the cellular transcription factor STAT3. EBV infection is rapidly followed by activation and increased expression of STAT3, which mediates relaxation of the intra-S phase cell-cycle checkpoint; this facilitates viral oncogene-driven cell proliferation. We now show that replication stress-associated DNA damage, which results from EBV infection, is detected by DDR. However, signaling downstream of ATR is impaired by STAT3, leading to relaxation of the intra-S phase checkpoint. We find that STAT3 interrupts ATR-to-Chk1 signaling by promoting loss of Claspin, a protein that assists ATR to phosphorylate Chk1. This loss of Claspin which ultimately facilitates cell proliferation is mediated by caspase 7, a protein that typically promotes cell death. Our findings demonstrate how STAT3, which is constitutively active in many human cancers, suppresses DDR, fundamental to tumorigenesis. This newly recognized role for STAT3 in attenuation of DDR, discovered in the context of EBV infection, is of broad interest as the biology of cell proliferation is central to both health and disease.

Establishment of Epstein-Barr virus growth-transformed lymphoblastoid cell lines.

Infection of B cells with Epstein-Barr virus (EBV) leads to proliferation and subsequent immortalization, resulting in establishment of lymphoblastoid cell lines (LCL) in vitro. Since LCL are latently infected with EBV, they provide a model system to investigate EBV latency and virus-driven B cell proliferation and tumorigenesis(1). LCL have been used to present antigens in a variety of immunologic assays(2, 3). In addition, LCL can be used to generate human monoclonal antibodies(4, 5) and provide a potentially unlimited source when access to primary biologic materials is limited(6, 7). A variety of methods have been described to generate LCL. Earlier methods have included the use of mitogens such as phytohemagglutinin, lipopolysaccharide(8), and pokeweed mitogen(9) to increase the efficiency of EBV-mediated immortalization. More recently, others have used immunosuppressive agents such as cyclosporin A to inhibit T cell-mediated killing of infected B cells(7, 10-12). The considerable length of time from EBV infection to establishment of cell lines drives the requirement for quicker and more reliable methods for EBV-driven B cell growth transformation. Using a combination of high titer EBV and an immunosuppressive agent, we are able to consistently infect, transform, and generate LCL from B cells in peripheral blood. This method uses a small amount of peripheral blood mononuclear cells that are infected in vitroclusters of cells can be demonstrated. The presence of CD23 with EBV in the presence of FK506, a T cell immunosuppressant. Traditionally, outgrowth of proliferating B cells is monitored by visualization of microscopic clusters of cells about a week after infection with EBV. Clumps of LCL can be seen by the naked eye after several weeks. We describe an assay to determine early if EBV-mediated growth transformation is successful even before microscopic clusters of cells can be demonstrated. The presence of CD23(hi)CD58(+) cells observed as early as three days post-infection indicates a successful outcome.

TNF-alpha is necessary for induction of coronary artery inflammation and aneurysm formation in an animal model of Kawasaki disease.

Kawasaki disease is the most common cause of multisystem vasculitis in childhood. The resultant coronary artery lesions make Kawasaki disease the leading cause of acquired heart disease in children in the developed world. TNF-alpha is a pleiotropic inflammatory cytokine elevated during the acute phase of Kawasaki disease. In this study, we report rapid production of TNF-alpha in the peripheral immune system after disease induction in a murine model of Kawasaki disease. This immune response becomes site directed, with migration to the coronary arteries dependent on TNF-alpha-mediated events. Production of TNF-alpha in the heart is coincident with the presence of inflammatory infiltrate at the coronary arteries, which persists during development of aneurysms. More importantly, inflammation and elastin breakdown in the coronary vessels are completely eliminated in the absence of TNF-alpha effector functions. Mice treated with the TNF-alpha-blocking agent etanercept, as well as TNFRI knockout mice, are resistant to development of both coronary arteritis and coronary aneurysm formation. Taken together, TNF-alpha is necessary for the development of coronary artery lesions in an animal model of Kawasaki disease. These findings have important implications for potential new therapeutic interventions in children with Kawasaki disease.