Extracorporeal photopheresis

user9876

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I came across this technique recently and thought it might interest people here since it is aimed at immune mediated diseases.Or to be more accurate t-cell lymphoma and graft vs host disease, there seems to have been some work in autoimmune disease as well but I've not managed to track down papers yet. I don't think i've seen it discussed here.

I thought what was interesting is that they talk of chaning ratios of different parts of the immune system and the effects that treating around 10% of cells seems to have on the rest.

For example

recent studies of patients undergoing a 6- to 12-month course of ECP treatment demonstrated an attenuation of Th1-mediated cytokine secretion by activated T-helper cells, a shift in the DC1/DC2 ratio favoring plasmacytoid rather than monocytoid dendritic cell profiles, and a decrease in antigen responsiveness by dendritic cells.
and
Selective effects of ECP on subpopulations of activated T cells have been observed in treated patients. Normalization of CD4/CD8 ratios has been described in CTCL patients,34 as well as a shift from predominantly Th2 to Th1 cytokine secretion. In the context of CTCL, the restoration of Th1 cytokine secretion increases IL-12 production by monocytes, which might subsequently inhibit Th2 cytokine secreting cells that are believed to be responsible for the clinical manifestations of CTCL.35
While monocytes appear to be resistant to the apoptotic effects of ECP, the induction of TNF-
secretion by photoactivated monocytes facilitates lymphocyte apoptosis.36 Further, photoactivation of monocytes by ECP has also been shown to enhance their differentiation into CD83+ CD36+ dendritic cells capable of phagocytosing the apoptotic T cells.37 In the presence of the costimulatory molecules, B7.1 and B7.2, these dendritic cells are capable of presenting tumor antigens from phagocytosed tumor cells in the context of MHC molecules and thus initiating cellular immune responses.38
As I understand it the technique it involves taking blood out, separating out the t-cells via a centrafuse treating them with UV light and a chemical then putting them back.

A couple of papers

http://www.nature.com/bmt/journal/v29/n9/full/1703529a.html
http://bloodjournal.hematologylibrary.org/content/112/4/1515.full
 

Jesse2233

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Hi Jesse, what is it? It this similar to PP or something else? Can you explain it in non-sciency terms? :D
Hahah I'll do my best!

So as I understand, it basically removes a portion of your blood, separates out the white cells, treats them with a special chemical and ultraviolet light which kills them, and then puts everything back into your body using two peripheral lines. It's done bi-weekly over a period of 6 months. They're not sure exactly how it works, but one theory is that the dead immune cells send a signal to the body to increase T-regs which in turn lower inflammation, clear chronic pathogens, and destroy autoantibodies.

I talked to my doctor about photopheresis vs immunoadsorbtion and plasmapheresis and he said that if it works, the benefit would be longer (or even permanent) with photopheresis because there's a potential for immune reset.

It's considered to be safer than immunosuppression and so can be used in cases where chronic infections might be present.

It's usually done for cancer and organ transplant but new data is showing benefit for autoimmunity as well. I would be patient zero for my case however, which my doctor made very clear

I thought the T cell mechanism of action was interesting given Mark Davis' findings and what Dr Chia told me last appointment about Dr Klimas' T-cell treatment experiment