Comparison of T-cell-depleted BMT and PBPCT with respect to chimerism, graft rejection, and leukemic relapse.
Chimerism analysis by DNA-based methods is a valuable diagnostic tool for monitoring engraftment and leukemic relapse after allogeneic BMT or PBPC transplantation (PBPCT). We investigated the chimerism after T-cell-depleted BMT (n = 32) in comparison with T-cell-depleted PBPCT (n = 39). BM grafts were T-cell depleted using the Campath-IgM antibody plus complement. For T-cell depletion of the PBPC grafts, a selection of CD34+ cells with or without a subsequent CD2/3 depletion was performed. In all patients, the T-cell dose of the transplant was < 10(6)/kg body weight. Between day 13 and day 120 after transplantation, chimerism analysis was done by RFLP or amplified fragment length polymorphism (PCR-AFLP), with a detection limit of 1%-5% recipient cells. In the BMT group, 8 of 32 (25%) patients showed a mixed chimerism, but only one graft rejection and no leukemic relapse occurred after a median follow-up of 41 (3-84) months. All patients with PBPCT revealed a complete chimerism of their granulocytes, and 38 of 39 patients showed complete chimerism of their lymphocytes. Follow-up time in these patients is 7 (2-21) months, with no graft rejection and two leukemic relapses. G-CSF-mobilized PBPC are superior to BM cells for full engraftment even after T-cell-depleted transplantation. The more relevant factor for developing complete chimerism seems to be the quantity and possibly the quality of the stem cells rather than the residual T-cell load of the graft. However, a mixed chimerism of the lymphocytes early after transplantation does not predict a higher rate of graft rejection or leukemic relapse.
Department of Transfusion Medicine and Red Cross Blood Center, Ulm, Germany.
M
M
Wiesneth
T
T
Schreiner
D
D
Bunjes
C
C
Bischof
E
E
Erne
B
B
Maccari
B
B
Kubanek
D000328:Adult; D016026:Bone Marrow Transplantation / Q000502:physiology*; D004247:DNA / Q000032:analysis / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006084:Graft Rejection; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007938:Leukemia / Q000628:therapy*; D008212:Lymphocyte Depletion; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D018183:Transplantation Chimera; D014184:Transplantation, Homologous; D016896:Treatment Outcome
D004247:DNA