BB02 Improves Therapeutical Effectiveness Of Extracorporeal Photopheresis With 8-MOP In a Murine Model Of Graft-Versus-Host Disease

Abstract

IntroductionExtracorporeal photopheresis (ECP) is a cell-based immunomodulatory therapy involving the separation of peripheral blood autologous mononuclear cells followed by ex-vivo administration of 8-methoxypsoralen (8-MOP) and UVA radiation before reinfusion. ECP is efficient for the treatment of multiple diseases mediated by unregulated T cell populations, such as cutaneous T cell lymphoma, autoinmune diseases or graft-versus-host disease (GVHD), the major complication after allogeneic bone marrow transplantation. Our aim in the present work was to compare the therapeutic effectiveness of 8-MOP with other two new compounds (BB01 and BB02) in a experimental murine model of GVHD. MethodsMurine GVHD was induced after transplanting bone marrow cells and splenocytes from donor Balb/c mice into C57Bl6J recipients previously conditioned with a lethal dose of 10 Gy split into two doses of 5 Gy spaced 24 hours apart. To investigate the therapeutic effectiveness of ECP with either 8-MOP, BB01 or BB02, splenocytes from separate cohorts of C57Bl6J with GVHD were isolated 12 days after transplantation, incubated with the different compounds, irradiated with UVA light and injected intravenously once a week for four weeks. Survival after transplantation was monitored daily and clinical GVHD was graded using a previously described score analyzing weight loss, posture (hunching), activity, skin integrity and fur texture (Cooke et al, 1996). Mice of each group were evaluated and graded from 0 to 2 for each criterion, obtaining a clinical index by summation of the five criteria scores (maximum index=10). ResultsMice treated weekly with BB02 showed a significant higher survival than those treated with 8-MOP (p=0,038), while BB01 had a similar effect to that of 8-MOP. Mice treated with either compound improved their clinical GVHD score compared to untreated mice group, being significantly lower with BB02 than with BB01 and 8-MOP (p=0,023). ConclusionsBB02 was more efficient than 8-MOP in the reversal of murine GVHD, while BB01 showed the same therapeutic effectiveness than 8-MOP. AcknowledgmentsWork financed by the Spanish Ministry of Science and Innovation (Ref: BFU2010-19599) and the Spanish Net of Cell Therapy (TerCel) from Institute of Health Carlos III. Disclosures:No relevant conflicts of interest to declare.