Placebo-Controlled Trial of an Oral BTK Inhibitor in Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating inflammatory disorder of the central nervous system (CNS), which involves autoimmune responses to myelin antigens. Studies in experimental autoimmune encephalomyelitis (EAE), an animal model for MS, have provided convincing evidence that T cells specific for self-antigens mediate pathology in these diseases. Until recently, T helper type 1 (Th1) cells were thought to be the main effector T cells responsible for the autoimmune inflammation. However more recent studies have highlighted an important pathogenic role for CD4(+) T cells that secrete interleukin (IL)-17, termed Th17, but also IL-17-secreting γδ T cells in EAE as well as other autoimmune and chronic inflammatory conditions. This has prompted intensive study of the induction, function and regulation of IL-17-producing T cells in MS and EAE. In this paper, we review the contribution of Th1, Th17, γδ, CD8(+) and regulatory T cells as well as the possible development of new therapeutic approaches for MS based on manipulating these T cell subtypes. © 2010 The Authors. Clinical and Experimental Immunology © 2010 British Society for Immunology.

Alemtuzumab, a humanized monoclonal antibody that targets CD52 on lymphocytes and monocytes, may be an effective treatment for early multiple sclerosis. In this phase 2, randomized, blinded trial involving previously untreated, early, relapsing-remitting multiple sclerosis, we assigned 334 patients with scores of 3.0 or less on the Expanded Disability Status Scale and a disease duration of 3 years or less to receive either subcutaneous interferon beta-1a (at a dose of 44 microg) three times per week or annual intravenous cycles of alemtuzumab (at a dose of either 12 mg or 24 mg per day) for 36 months. In September 2005, alemtuzumab therapy was suspended after immune thrombocytopenic purpura developed in three patients, one of whom died. Treatment with interferon beta-1a continued throughout the study. Alemtuzumab significantly reduced the rate of sustained accumulation of disability, as compared with interferon beta-1a (9.0% vs. 26.2%; hazard ratio, 0.29; 95% confidence interval [CI], 0.16 to 0.54; P<0.001) and the annualized rate of relapse (0.10 vs. 0.36; hazard ratio, 0.26; 95% CI, 0.16 to 0.41; P<0.001). The mean disability score on a 10-point scale improved by 0.39 point in the alemtuzumab group and worsened by 0.38 point in the interferon beta-1a group (P<0.001). In the alemtuzumab group, the lesion burden (as seen on T(2)-weighted magnetic resonance imaging) was reduced, as compared with that in the interferon beta-1a group (P=0.005). From month 12 to month 36, brain volume (as seen on T(1)-weighted magnetic resonance imaging) increased in the alemtuzumab group but decreased in the interferon beta-1a group (P=0.02). Adverse events in the alemtuzumab group, as compared with the interferon beta-1a group, included autoimmunity (thyroid disorders [23% vs. 3%] and immune thrombocytopenic purpura [3% vs. 1%]) and infections (66% vs. 47%). There were no significant differences in outcomes between the 12-mg dose and the 24-mg dose of alemtuzumab. In patients with early, relapsing-remitting multiple sclerosis, alemtuzumab was more effective than interferon beta-1a but was associated with autoimmunity, most seriously manifesting as immune thrombocytopenic purpura. The study was not powered to identify uncommon adverse events. (ClinicalTrials.gov number, NCT00050778.) 2008 Massachusetts Medical Society

Background Macrophages play a dual role in multiple sclerosis (MS) pathology. They can exert neuroprotective and growth promoting effects but also contribute to tissue damage by production of inflammatory mediators. The effector function of macrophages is determined by the way they are activated. Stimulation of monocyte-derived macrophages in vitro with interferon-γ and lipopolysaccharide results in classically activated (CA/M1) macrophages, and activation with interleukin 4 induces alternatively activated (AA/M2) macrophages. Methods For this study, the expression of a panel of typical M1 and M2 markers on human monocyte derived M1 and M2 macrophages was analyzed using flow cytometry. This revealed that CD40 and mannose receptor (MR) were the most distinctive markers for human M1 and M2 macrophages, respectively. Using a panel of M1 and M2 markers we next examined the activation status of macrophages/microglia in MS lesions, normal appearing white matter and healthy control samples. Results Our data show that M1 markers, including CD40, CD86, CD64 and CD32 were abundantly expressed by microglia in normal appearing white matter and by activated microglia and macrophages throughout active demyelinating MS lesions. M2 markers, such as MR and CD163 were expressed by myelin-laden macrophages in active lesions and perivascular macrophages. Double staining with anti-CD40 and anti-MR revealed that approximately 70% of the CD40-positive macrophages in MS lesions also expressed MR, indicating that the majority of infiltrating macrophages and activated microglial cells display an intermediate activation status. Conclusions Our findings show that, although macrophages in active MS lesions predominantly display M1 characteristics, a major subset of macrophages have an intermediate activation status.