NeuroImmunology

AbstractOBJECTIVE:

Novel treatments such as natalizumab and fingolimod achieve their therapeutic efficacy in multiple sclerosis (MS) by blocking access of subsets of immune cells into the central nervous system, thus creating nonphysiological intrathecal immunity. In contrast, daclizumab, a humanized monoclonal antibody against the alpha chain of the IL-2 receptor, has a unique mechanism of action with multiple direct effects on innate immunity. As cellular intrathecal abnormalities corresponding to MS have been well defined, we asked how daclizumab therapy affects these immunological hallmarks of the MS disease process.

METHODS:

Nineteen subpopulations of immune cells were assessed in a blinded fashion in the blood and 50-fold concentrated cerebrospinal fluid (CSF) cell pellet in 32 patients with untreated relapsing-remitting MS (RRMS), 22 daclizumab-treated RRMS patients, and 11 healthy donors (HDs) using 12-color flow cytometry.

RESULTS:

Long-term daclizumab therapy normalized all immunophenotyping abnormalities differentiating untreated RRMS patients from HDs. Specifically, strong enrichment of adaptive immune cells (CD4+ and CD8+ T cells and B cells) in the CSF was reversed. Similarly, daclizumab controlled MS-related increases in the innate lymphoid cells (ILCs) and lymphoid tissue inducer cells in the blood and CSF, and reverted the diminished proportion of intrathecal monocytes. The only marker that distinguished daclizumab-treated MS patients from HDs was the expansion of immunoregulatory CD56(bright) NK cells.

INTERPRETATION:

Normalization of immunological abnormalities associated with MS by long-term daclizumab therapy suggests that this drug's effects on ILCs, NK cells, and dendritic cell-mediated antigen presentation to CD4+ and CD8+ T cells are critical in regulating the MS disease process.

Via Krishan Maggon

The central nervous system (CNS) largely comprises nonregenerating cells, including neurons and myelin-producing oligodendrocytes, which are particularly vulnerable to immune cell–mediated damage. To protect the CNS, mechanisms exist that normally restrict the transit of peripheral immune cells into the brain and spinal cord, conferring an “immune-specialized” status. Thus, there has been a long-standing debate as to how these restrictions are overcome in several inflammatory diseases of the CNS, including multiple sclerosis (MS). In this review, we highlight the role of the meninges, tissues that surround and protect the CNS and enclose the cerebral spinal fluid, in promoting chronic inflammation that leads to neuronal damage. Although the meninges have traditionally been considered structures that provide physical protection for the brain and spinal cord, new data have established these tissues as sites of active immunity. It has been hypothesized that the meninges are important players in normal immunosurveillance of the CNS but also serve as initial sites of anti-myelin immune responses. The resulting robust meningeal inflammation elicits loss of localized blood-brain barrier (BBB) integrity and facilitates a large-scale influx of immune cells into the CNS parenchyma. We propose that targeting the cells and molecules mediating these inflammatory responses within the meninges offers promising therapies for MS that are free from the constraints imposed by the BBB. Importantly, such therapies may avoid the systemic immunosuppression often associated with the existing treatments.

Via Krishan Maggon

ABSTRACT

Objective: This study evaluated the efficacy and safety of ATL1102, an antisense oligonucleotide that selectively targets the RNA for human CD49d, the α subunit of very late antigen 4, in patients with relapsing-remitting multiple sclerosis (RRMS).

Methods: In a multicenter, double-blind, placebo-controlled randomized phase II trial, 77 patients with RRMS were treated with 200 mg of ATL1102 subcutaneously injected 3 times in the first week and twice weekly for 7 weeks or placebo and monitored for a further 8 weeks. MRI scans were taken at baseline and weeks 4, 8, 12, and 16. The primary endpoint was the cumulative number of new active lesions (either new gadolinium-enhancing T1 lesions or nonenhancing new or enlarging T2 lesions) at weeks 4, 8, and 12.

Results: A total of 72 patients completed the study and 74 intention-to-treat patients were assessed. ATL1102 significantly reduced the cumulative number of new active lesions by 54.4% compared to placebo (mean 3.0 [SD 6.12] vs 6.2 [9.89], p = 0.01). The cumulative number of new gadolinium-enhancing T1 lesions was reduced by 67.9% compared to placebo (p = 0.002). Treatment-emergent adverse events included mild to moderate injection site erythema and decrease in platelet counts that returned to within the normal range after dosing.

Conclusions: In patients with RRMS, ATL1102 significantly reduced disease activity after 8 weeks of treatment and was generally well-tolerated. This trial provides evidence for the first time that antisense oligonucleotides may be used as a therapeutic approach in neuroimmunologic disorders.

Classification: This study provides Class I evidence that for patients with RRMS, the antisense oligonucleotide ATL1102 reduces the number of new active head MRI lesions.

Via Krishan Maggon

Abstract

Multiple sclerosis (MS) is a typical CD4 T cell-mediated autoimmune disease of the central nervous system (CNS) that leads to inflammation, demyelination, axonal damage, glial scarring and a broad range of neurological deficits. While disease-modifying drugs with a good safety profile and moderate efficacy have been available for 20 years now, a growing number of substances with superior therapeutic efficacy have recently been introduced or are in late stage clinical testing. Daclizumab, a humanized neutralizing monoclonal antibody against the α-chain of the Interleukin-2 receptor (IL-2Rα, CD25), which had originally been developed and approved to prevent rejection after allograft renal transplantation, belongs to the latter group.

 

Clinical efficacy and safety of daclizumab in MS has so far been tested in several smaller phase II trials and recently two large phase II trials (combined 912 patients), and has shown efficacy regarding reduction of clinical disease activity as well as CNS inflammation. A phase III clinical trial is ongoing till March 2014 (DECIDE study, comparison with interferon (IFN) β-1a in RRMS). Furthermore, the existing safety data from clinical experience in kidney transplantation and in MS appears favorable.

 

Apart from the promising clinical data mechanistic studies along the trials have provided interesting novel insights not only about the mechanisms of daclizumab treatment, but in general about the biology of IL-2 and IL-2 receptor interactions in the human immune system. Besides blockade of recently activated CD25+T cells daclizumab appears to act through additional mechanisms including the expansion of immune regulatory CD56bright natural killer (NK) cells, the blockade of cross-presentation of IL-2 by dendritic cells (DC) to T cells, and the reduction of lymphoid tissue inducer cells.

Via Krishan Maggon

RT @MSDForum: Daclizumab did well in phase 3 trials for #MS. Here's the story behind the story http://t.co/PFzsfHqKs1

 

 an analysis of samples from blood and cerebrospinal fluid suggests that daclizumab nudges the abnormal numbers of innate and adaptive immune cells in RRMS back to more normal physiological levels found in people without MS (Lin et al., 2014).

 

the therapeutic efficacy of daclizumab paralleled the expansion of a key target cell population, called CD56bright natural killer cells (CD56bright NK). That raised hopes for a biomarker that could measure who was responding and predict who would do best.

 

 

Via Krishan Maggon