Blocking VLA-2 doesn't encourage PML.

[TwistedHelix]

The problem with drugs like Tysabri is that they not only prevent white blood cells from crossing the blood brain barrier and causing harm, they prevent them crossing and doing good things, like keeping viruses and PML in check.
This team took a different approach by blocking a molecule which interacts with the extracellular matrix, (basically, parts of tissue which are not part of the cell), and thus, so long as they get the timing right, reducing the clinical signs of EAE.


Modulation of Experimental Autoimmune Encephalomyelitis by VLA-2 Blockade.
Brain Pathol. 2007 Jan;17(1):45-55
Authors: Tsunoda I, Terry EJ, Marble BJ, Lazarides E, Woods C, Fujinami RS
Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). Adhesion molecules play important roles in cell-cell and cell-extracellular matrix (ECM) interactions in inflammation. Blocking the interaction between inflammatory cells and vascular endothelia can prevent cell entry into tissues and harmful inflammatory responses, that is, autoimmunity, but could also limit immunosurveillance by anti-viral T cells in sites of infection or latency. Development of progressive multifocal leukoencephalopathy in patients treated with antibody against very late antigen (VLA)-4 prompted us to explore an alternative therapeutic approach. We used an antibody against the integrin alpha2, VLA-2, that interacts with ECM, not vascular endothelium. SJL/J mice were sensitized with myelin proteolipid protein (PLP)(139-151) peptide to induce experimental autoimmune encephalomyelitis (EAE), an animal model for MS. Treatment of mice with VLA-2 antibody suppressed clinical signs and CNS inflammation of EAE, when antibody was given immediately after disease onset. In contrast, VLA-4 or VLA-2 antibody treatment of mice during the priming or remission phase of EAE had minor effects on the disease's clinical course. No differences were found in lymphoproliferative responses to PLP(139-151) among treatment groups. Data suggest that blocking cell-ECM interactions can be an alternative therapy for ,
PMID: 17493037 [PubMed - in process]
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