[Ex vivo chemical modification of graft cells by methoxy polyethylene glycol alleviates graft versus host disease after haploidentical stem cell transplantation in mice].

This study was aimed to explore the effect of ex vivo chemical modification of graft cells with methoxy polyethylene glycol (mPEG) on graft versus host disease (GVHD) after haploidentical stem cell transplantation in neonatal mice and its influence on activity of the stem cells. The modified and non-modified spleen cells of adult CB6F1 mice were injected into the abdominal cavity of neonatal BALB/c mice with 5x10(6) spleen cells per mouse, and GVHD were measured by spleen index (SI). Furthermore, the modified and non-modified mixture of bone marrow and spleen cells (BMS) were transplanted to haploidentical lethally irradiated adult BALB/c mice via tail vein with 2x10(5) BMS per mouse, and the colony forming units of spleens (CFU-S) were counted on the eighth day after irradiation. The results indicated that SI1 in modification group were lower than that in non-modification group, and SI2 in modification group was <1.3, showing that GVHD in modification group were less severe. The numbers of CFU-S formed in both modification group and non-modification group were not significantly different (p>0.05), indicating that the activity of the stem cells were not affected by mPEG modification. In conclusion, the modification of graft cells with mPEG alleviates GVHD after haploidentical stem cell transplantation in neonatal mice, and do not influence the activity of the stem cells.