Photopheresis with UV-A light and 8-methoxypsoralen leads to cell death and to release of blebs with anti-inflammatory phenotype in activated and non-activated lymphocytes.
BACKGROUND
Extracorporeal photopheresis is a therapy for treatment of autoimmune diseases, cutaneous T-cell lymphoma, organ graft rejection as well as graft-versus-host diseases. The exact mechanism how the combination of 8-methoxypsoralen plus UV-A irradiation (PUVA) acts is still unclear. We investigated the cell death of activated and non-activated lymphocytes after PUVA treatment as well as the rate of released blebs and their antigen composition.


RESULTS
In presence of 8-MOP, UV-A light highly significantly increased the cell death of activated lymphocytes. The same was observed to a lesser extent in non-activated cells. Blebs derived from activated lymphocytes after PUVA treatment showed the highest surface exposition of phosphatidylserine. These blebs also displayed a high exposure of the antigens CD5 and CD8 as well as a low exposure of CD28 and CD86.


CONCLUSIONS
PUVA treatment exerts anti-inflammatory effects by inducing apoptosis and apoptotic cell-derived blebs with immune suppressive surface composition.
Stadler
K
K
Department for Internal Medicine 3, University Hospital Erlangen, Germany.
Frey
B
B
Munoz
L E
LE
Finzel
S
S
Rech
J
J
Fietkau
R
R
Herrmann
M
M
Hueber
A
A
Gaipl
U S
US
D000954:Antigens, Surface / Q000276:immunology; D017209:Apoptosis; D001768:Blister / Q000276:immunology; D002478:Cells, Cultured; D006801:Humans; D007249:Inflammation / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000528:radiation effects; D008214:Lymphocytes / Q000187:drug effects* / Q000528:radiation effects*; D008730:Methoxsalen / Q000494:pharmacology*; D010718:Phosphatidylserines / Q000276:immunology; D017893:Photopheresis; D014466:Ultraviolet Rays
D000954:Antigens, Surface; D010718:Phosphatidylserines; D008730:Methoxsalen