Effects of chimerism on graft versus host disease recurrence and survival after HLA identical marrow transplantation in Iran

ABSTRACT

The co-existence of recipient's hamatopoietic systems after allogeneic marrow transplantation is called mixed chimerism. Chimerism analysis provides a national method of different conditioning regimens, graft-versus-host disease [GVHD], prophylactic regimens, and cellular therapy to promote engraftment. The association of mixed chimerism with acute graft-versus-host disease [GVHD], disease recurrence, survival, and relapse free survival was investigated in 91 patients 12 and 79 of whom underwent either bone or peripheral blood HLA-identical marrow transplantation respectively. Chimerism was assessed using multiplex amplification of shorty tandem repeats [STR-PCR].cases included thalassemics [19 subjects], AML [29], ALL [20], CMT [18] and others [5].Median age was 21 [age range of 3-50]. There were 38 females [41.8%] and 53 males [58.2%]. Conditioning was busulfan plus cyclophosphamide in 34 patients, busulfan plus fludarabin in 51 patients and busulfan plus fludarabin plus anti-thymocyte globulin in 6 patients. Median of follow up was 13 months. Data was analyzed using SPSS statistical software. On day 30 after transplantation, mixed chimerism [MC] was observed in 15 patients [16.5%], complete donor chimerism [CC] in 72 patients [79%], and no chimerism in 4 patients. The incidence of acute GVHD was significantly lower in mixed chimeras that in complete chimeras [p=0.01] but there was no significant difference in acute GVHD grade [I, II vs. III, IV] between two groups. The incidence of relapse and overall survival were 17.6% and 88.9% respectively showing no significant difference between MC and CC. Relapse free survival was 80.2% and significantly different between two groups. Despite some previous reports, we found no significant difference in survival and relapse rate between MC and CC. Relapse free survival was 80.2% and not significantly different between tw ogroup