December 4, 2010 at 9:06pm
We are often told that MS is an autoimmune disease, as evidenced by the seemingly unprovoked immune activity against myelin. But what we are not told is that this same process happens in the brains of those who have strokes and cerebrovascular disease.
In fact, in stroke survivors there is actual more immune response to myelin than there is in people with MS.
In fact, in stroke survivors there is actual more immune response to myelin than there is in people with MS.
A new paper from 2010--- Post-ischemic immune response to stroke
Here is a link to the full paper.
"To date, there has been little interest in exploring the possibility that autoimmune responses to brain antigens might affect outcome from stroke. There are, however, studies that document the fact immune responses to brain antigens do occur following stroke.
For instance, lymphocytes from stroke survivors show more activity against MBP than the lymphocytes from patients with multiple sclerosis.18,19
In addition, myelin-reactive T cells are found in higher numbers among patients with cerebrovascular disease.20 These data thus provide evidence that a cellular immune response to brain antigens occurs following stroke.
Furthermore, there are increased titers of antibodies to brain antigens, including neurofilaments and portions of N-methyl-D-aspartate receptor, following stroke, indicating that there is also the development of a humoral response to these antigens.21,22 The immune response to CNS antigens after stroke is likely just an epiphenomena of stroke given that cerebral ischemic injury to the blood–brain barrier allows for the systemic immune system to come into contact with the antigens that are normally sequestered from it. Nonetheless, it is possible that this response leads to "collateral damage"; whether these immune responses affect outcome from stroke is largely an unanswered question."
---Why has there been "little interest" in studying the autoimmune response of the body to stroke? Why have we been told that myelin antigens are found only in the cerebral spinal fluid of those with MS? These antigens are found in higher levels following a stroke.
"Furthermore, although immunosuppressive strategies might decrease the risk of developing a Th1 (and possibly Th17?) response after stroke, such interventions might increase the risk infection, a risk that is already high in the poststroke period. On the other hand, strategies to enhance the immune response to prevent infection in the poststroke period might increase the risk of developing a detrimental Th1 (and possibly Th17?) immune response to brain, and, as already discussed, these responses might predispose to worse functional outcome from stroke. It is also in the realm of possibility that the development of immune responses to brain antigens, be they cellular or humoral, may have longer-lasting effects. For instance, it is appreciated that stroke is a potent risk factor for dementia, and it could be that autoimmune responses to brain contribute to cognitive decline and even the progression of white matter disease.42 Future clinical studies will need to address the contribution of the postischemic immune response to these long-term outcomes.
In summary, the nature of the postischemic immune response affects outcome from stroke (Figure). Modulation of this response may be a viable approach to improving outcome in stroke, but there are potential dangers associated with immunomodulation. A more complete understanding of the endogenous immune response following stroke is needed to safely manipulate this response in the poststroke period."
Sadly, we know all too well about the potential dangers of brain viruses (like PML) associated with immunomodulation. Interesting that it is considered too dangerous to give these treatments to those with stroke....but for those with MS, it is an "acceptable risk." Perhaps we need to understand the disease mechanism of MS first.
Joan
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