Mixed lymphohaemopoietic chimerism and graft-versus-lymphoma effects after non-myeloablative therapy and HLA-mismatched bone-marrow transplantation.
BACKGROUND
HLA-mismatched donor bone-marrow transplantation after standard myeloablative conditioning therapy for haematological malignant disorders has been limited by severe graft-versus-host disease (GVHD) and graft failure. We tested a new approach to find out whether lymphohaemopoietic graft-versus-host reactions could occur without excessive GVHD in mixed haemopoietic chimeras produced across HLA barriers with non-myeloablative conditioning.


METHODS
Five patients with refractory non-Hodgkin lymphoma underwent bone-marrow transplantation from haploidentical related donors sharing at least one HLA A, B, or DR allele on the mismatched haplotype. Conditioning included cyclophosphamide and thymic irradiation before transplantation, and antithymocyte globulin before and after transplantation. The only other GVHD prophylaxis was cyclosporin.


RESULTS
Four of five patients were evaluable and showed engraftment. Mixed haemopoietic chimerism was established, with a predominance of donor lymphoid tissue and varying degrees of myeloid chimerism. Two patients were in GVHD-free states of complete and partial clinical remission at 460 and 103 days after bone-marrow transplantation.


CONCLUSIONS
Mixed chimerism can be induced in adult recipients of HLA-mismatched bone-marrow transplantation by a non-myeloablative conditioning regimen. The antilymphoma responses seen in two patients suggest that allogeneic bone-marrow transplantation without myeloablative conditioning might have potent immunotherapeutic benefits.
Sykes
M
M
Transplantation Biology Research Center, Surgical Service, Massachusetts General Hospital and Harvard Medical School, Boston 02129, USA. sykes@helix.mgh.harvard.edu
Preffer
F
F
McAfee
S
S
Saidman
S L
SL
Weymouth
D
D
Andrews
D M
DM
Colby
C
C
Sackstein
R
R
Sachs
D H
DH
Spitzer
T R
TR
D000328:Adult; D016026:Bone Marrow Transplantation; D005434:Flow Cytometry; D006084:Graft Rejection; D006086:Graft vs Host Disease; D006239:Haplotypes; D006650:Histocompatibility Testing; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000097:blood / Q000628:therapy*; D008875:Middle Aged; D019172:Transplantation Conditioning / Q000379:methods*; D014184:Transplantation, Homologous; D016896:Treatment Outcome