Rituximab and multiple sclerosis

In vivo imaging in autoimmune diseases in the central nervous system

Intravital imaging is becoming more popular and is being used to visualize cellular motility and functions. In contrast to in vitro analysis, which resembles in vivo analysis, intravital imaging can be used to observe and analyze cells directly in vivo. In this review, I will summarize recent imaging studies of autoreactive T cell infiltration into the central nervous system (CNS) and provide technical background. During their in vivo journey, autoreactive T cells interact with many different cells. At first, autoreactive T cells interact with endothelial cells in the airways of the lung or with splenocytes, where they acquire a migratory phenotype to infiltrate into the CNS. After arriving at the CNS, they interact with endothelial cells of the leptomeningeal vessels or the choroid plexus before passing through the blood-brain barrier. CNS-infiltrating T cells become activated by recognizing endogenous autoantigens presented by local antigen-presenting cells (APCs). This activation was visualized in vivo by using protein-based sensors. One such sensor detects changes in intracellular calcium concentration as an early marker of T cell activation. Another sensor detects translocation of Nuclear factor of activated T-cells (NFAT) from cytosol to nucleus as a definitive sign of T cell activation. Importantly, intravital imaging is not just used to visualize cellular behavior. Together with precise analysis, intravital imaging deepens our knowledge of cellular functions in living organs and also provides a platform for developing therapeutic treatments.

A biodegradable nanoparticle platform for the induction of antigen-specific immune tolerance for treatment of autoimmune disease

Targeted immune tolerance is a coveted therapy for the treatment of a variety of autoimmune diseases, as current treatment options often involve nonspecific immunosuppression. Intravenous (iv) infusion of apoptotic syngeneic splenocytes linked with peptide or protein autoantigens using ethylene carbodiimide (ECDI) has been demonstrated to be an effective method for inducing peripheral, antigen-specific tolerance for treatment of autoimmune disease. Here, we show the ability of biodegradable poly(lactic-co-glycolic acid) (PLG) nanoparticles to function as a safe, cost-effective, and highly efficient alternative to cellular carriers for the induction of antigen-specific T cell tolerance. We describe the formulation of tolerogenic PLG particles and demonstrate that administration of myelin antigen-coupled particles both prevented and treated relapsing-remitting experimental autoimmune encephalomyelitis (R-EAE), a CD4 T cell-mediated mouse model of multiple sclerosis (MS). PLG particles made on-site with surfactant modifications surpass the efficacy of commercially available particles in their ability to couple peptide and to prevent disease induction. Most importantly, myelin antigen-coupled PLG nanoparticles are able to significantly ameliorate ongoing disease and subsequent relapses when administered at onset or at peak of acute disease, and minimize epitope spreading when administered during disease remission. Therapeutic treatment results in significantly reduced CNS infiltration of encephalitogenic Th1 (IFN-γ) and Th17 (IL-17a) cells as well as inflammatory monocytes/macrophages. Together, these data describe a platform for antigen display that is safe, low-cost, and highly effective at inducing antigen-specific T cell tolerance. The development of such a platform carries broad implications for the treatment of a variety of immune-mediated diseases.

Experience with low-dose rituximab in off-label indications at two tertiary hospitals

BACKGROUND

Rituximab is a monoclonal antibody directed against B cells and is increasingly used to treat a variety of autoimmune conditions. Most published evidence reporting the successful use of rituximab in off-label indications has empirically used a high-dose regimen (either 375 mg/m(2) weekly for 4 weeks, or 1000 mg × 2), which is the approved course of treatment for lymphoma and rheumatoid arthritis patients.

AIMS

The aims of this report are to review the indications, outcomes and adverse events of low-dose (500 mg twice, given 1-2 weeks apart), off-label use of rituximab in our institutions, and to review the available evidence.

METHODS

We performed a retrospective audit of the off-label use of low-dose rituximab at two university teaching, tertiary referral hospitals, from mid-2008 until the end of 2011.

RESULTS

Off-label rituximab was given to 52 patients (53 indications) across a heterogeneous group of autoimmune conditions. Outcomes were known for 46 conditions (affecting 45 patients), and of these, complete responses were observed in 16 (35%) conditions and a further 19 (41%) had a partial response. There was no response to rituximab in 11 (24%) patients. There were eight significant adverse events, mostly related to infectious complications.

CONCLUSION

This case series suggests that low-dose courses of rituximab can be used off-label to treat several severe and/or refractory immunological disorders with a reasonable safety profile; however, further trials are required in many off-label indications.

Effects of rituximab on lymphocytes in multiple sclerosis and neuromyelitis optica

OBJECTIVE

To investigate the effect of rituximab, a B-cell targeted therapy that is used in the treatment of multiple sclerosis (MS) and neuromyelitis optica (NMO), on other immune cells such as CD4+ and CD8+ T-cells in patients with MS and NMO.

DESIGN, SETTING AND PATIENTS

This is a retrospective study of all patients with MS or NMO who received at least one rituximab infusion at the UCSF MS tertiary care center between May 2005 and July 2011.

MAIN OUTCOME MEASURES

Linear mixed models were used to assess (a) how post-infusion cell counts changed over time compared to pre-infusion levels and one another; (b) whether the cell counts were different over multiple courses of rituximab; and (c) what was the dosing effect on the cell counts over time.

RESULTS

Rituximab initially reduced CD4+ (by 26%, p=0.0005) and CD8+ (by 22%, p=0.0006) T-cells, although these changes were only transient. Subsequent treatments with rituximab did not result in a significant drop in CD4+ or CD8+ T-cells. Changes in other cell types were also typically more marked after the first cycle of rituximab than after additional treatments. The total dose of rituximab received did not appear to have a significant effect.

CONCLUSIONS

Although transient, rituximab-induced decrease in CD4+ and CD8+ T-cells may increase the risk of infection in susceptible individuals.

CD21 positive B cell: a novel target for treatment of multiple sclerosis

Etiologic-based therapy is an ideal pharmacological option to treat or prevent diseases. There is no known etiology for multiple sclerosis (MS); however, environmental risk factors have been suggested to predispose genetically susceptible people to be affected by the disease. One of these risk factors is infection with Epstein-Barr virus (EBV). Eradication of this virus has not been effective in modulation of MS, probably due to being inhabitant in the CD21 (EBV receptor) positive B cells. To eradicate this virus, targeting CD21 on these EBV-infected B cells is hypothesized here. A sequential study plan to test this hypothesis has been suggested too. This study might eventually suggest an effective immunopharmacological strategy to treat MS. Moreover, testing this strategy will help in better clarification of the role of EBV in MS disease triggering and predisposition.

Current and future therapies for multiple sclerosis

With the introduction of interferon- β 1b in 1993 as the first FDA-approved treatment for multiple sclerosis, the era of treatment of this incurable disease began, and its natural course was permanently changed. Currently, seven different treatments for patients with multiple sclerosis with different mechanisms of action and dissimilar side effect profiles exist. These medications include interferon- β 1a intramuscular (Avonex), interferon- β 1a subcutaneous (Rebif), interferon- β 1b subcutaneous (Betaseron/Extavia), glatiramer acetate (Copaxone), natalizumab (Tysabri), fingolimod (Gilenya), teriflunomide (Aubagio), and mitoxantrone (Novantrone). In addition, a large number of clinical trials are being conducted to assess the safety and efficacy of various experimental agents in patients with multiple sclerosis, including alemtuzumab, dimethyl fumarate, laquinimod, rituximab, daclizumab, and cladribine. In this paper, the author presents a concise and comprehensive review of present and potential treatments for this incurable disease.