So far,it is thought that graft-versus-leukemia effect induced by immune cell can eliminate tumor cells in allogeneic hematopoietic stem cell ransplantation,which can reach the aim of cure.But graft versus host disease(GVHD),especial acute GVHD,is a thorny question in application of allogenetic hematopoietic stem cell transplantation.It is also the main reason for cripple and death after transplantation.Application of drugs those can control GVHD often inhibits graft-versus-leukemia effect.At the same time,the transplantation efficiency decrease and the chance of infection increase.The ideal method is to make the T cell be in activated state and keep graft-versus-leukemia effect,but inhibit specific alloantigens.Some new discoveries about classical antigen-presenting cells and dendritic cells,modified transplant method,as well as application of mesenchymal stem cells and regulate T cell,suggest the new direction for prevention and treatment of GVHD.

Objective:To observe the effect of anti-lymphocyte globulin(ALG)combined with cyclosporin A(CsA)in treatment of severe aplastic anemia(SAA).Methods:Forty-three patients with SAA received ALG [15mg/(kg?d)once a day for5d],CsA [5mg/(kg?d)for6months]and androgen(80mg,tid)for more than6months.Results:After6months,the blood corpuscle counts of patients increased(P