What are the basic hypotheses of the tolerogenic theory?

The tolerogenic theory posits that extracorporeal photopheresis (ECP) efficacy may be ascribed to the induction of immunologic tolerance. This tolerance may be achieved through one or more factors that occur following the reinfusion of cells induced to undergo apoptosis. The first factor is a modification in the antigen-presenting cell (APC) population. In the absence of danger signals, uptake of apoptotic cells can prevent the maturation of dendritic cells and inhibit their antigen presenting capacity.^5,16 Induction of tolerance may also be mediated by increased production of TGF-beta and IL-10. ^8,10,14 Conversely, a decrease in pro-inflammatory cytokines such as TNF and IL-12 has also been shown after ECP. ^1,5 Another possible factor is the induction of regulatory T-cells, or Tregs. Regulatory T-cells have been shown to contribute to tolerance via several actions, including controlling APC maturation and effector cell responses. ^2,9,15,17

References

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5. Data on file, Therakos, Inc.
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