A Pilot Study of Mycophenolate Mofetil for the Prophylaxis and Treatment of Graft-Versus-Host Disease.

Graft-versus-host disease (GVHD) is a serious complication of allogeneic peripheral blood stem cell transplantation (PBSCT), which contribute to morbidity and mortality after transplantation. Approximately half of the patients that undergo allogeneic stem cell transplantation develop severe acute or chronic graft-versus-host disease [Shulman HM et al. Am J Med, 1980], which varies with the degree of histoincompatibility, the recipient and donor ages, the source and quality of donor T lymphocytes, the incidence of cytomegalovirus infection,and type of GVHD prophylaxis strategy. The combination of immunosuppressive drugs, CsA and short-course MTX is a standard regiment for prevention of GVHD after BMT [Nademanee A et al. Blood, 1995], and have been shown in randomize trials to be superior to either drug alone in preventing severe GVHD [Storb R N Engl J Med.1986]. Although the efficacy of the regimens in preventing GVHD, the incidence reported for GVHD after transplantation is 38–68%. Each of these agents is also associated with significant organ toxicity. MMF is an new immunosuppressive drug, which selectively inhibits proliferation of T and B lymphocytes, formation of antibodies, and glycosylation of adhesion molecules by inhibition purine nucleotide synthesis and depleting the lymphocytes and monocytes of guanosine triphosphate. In patients undergoing renal and heart transplantation, it has been successfully used to prevent graft rejection [Lang P et al.Transplantation, 2005]. We compared the effects of MMF+ CsA+ MTX as GVHD prophylaxis vs CsA + MTX in patients undergoing allogeneic peripheral blood stem cell transplantation. In all, 33 patients were enrolled in this study. The first group, of 16 patients, received CsA at 3mg/kg i.v. from day −1 to +30 day and MTX was on 15mg/m² day +1 and 10mg/m² day +3, +6, +11. The other group, of 17 patients received MMF 1g/d day −7 until day 0 and CsA + MTX. Here we used flow cytometric analysis technique to measure the changes of T cell subsets before and after treatment of MMF and CsA. Our study showed the incident of aGVHD is 25% when we combined standard GVHD proplylaxis with MMF after PBSCT, Which significantly reduce the risk of aGVHD than the combination of CsA and MTX (58.8%). Therefore, MMF is an effective drug in prophylaxis of aGVHD. Chronic GVHD is a late complication of PBSCT, Which develops approximately 30% in related donor HLA-matched allografts, and 60–70% in HLA-unmatched. The incident is not reduce with the development of aGVHD prophylaxis, Our result showed that the incident of cGVHD in research group (25%) is the same as the control group (23.5%). It seems that MMF is not reduce the incident of cGVHD, which may be different frome aGVHD. Our conclude that the number of CD3⁺ CD4⁺T cells decreased after the treatment of MMF, and those of CD3⁺ CD8⁺T cells increased,with reduction of the CD4⁺/CD8⁺ ratio. the number of CD25⁺ CD4⁺ and CD69⁺ CD8⁺ T cells were all increase. It seems that MMF may preferably effect on the CD3⁺CD4⁺T cells and the combination of MMF with C_SA and MTX can significantly reduce the incidence of acute graft-vost-host diease, It appears to have a synergic action with CSA for the treatment of aGVHD.