Chimerism analysis in long-term survivor patients after bone marrow transplantation for severe aplastic anemia.
OBJECTIVE
Allogeneic bone marrow transplantation (BMT) is the most common treatment for young patients with severe aplastic anemia (SAA). Late graft failure represents one of the possible unfavorable outcomes in this setting. Mixed chimerism might represent a risk factor for late graft failure. We examined this relationship by studying chimerism in long-term survivor SAA patients after allogeneic BMT.


METHODS
We analyzed long-term hematopoietic chimerism in 15 patients who received BMTs for SAA: 9 with an irradiation-based conditioning regimen and 6 with ATG. We used a PCR method targeting VNTR loci. Sensitivity of the technique ranged between 0.5 and 1.5%.


RESULTS
All patients conditioned with radiation-based schemes showed complete donor chimerism. Conversely, out of six patients who received cyclophosphamide and ATG as a conditioning regimen, only one of them had late graft failure (day +168). In this patient, durable mixed chimera status was first detected two months after BMT.


CONCLUSIONS
Our results suggest that in long-term survivors of SAA after BMT there is almost always complete donor chimerism in both irradiated and ATG-conditioned recipients. Mixed chimerism might predict graft failure in these patients.
Gomez
J R
JR
Department of Hematology, Reina Sofia Hospital, Cordoba, Spain.
Garcia
M J
MJ
Serrano
J
J
Sanchez
J
J
Falcon
M
M
Castillejo
J A
JA
Navarro
J A
JA
Martin
C
C
Torres
A
A
D000293:Adolescent; D000328:Adult; D000741:Anemia, Aplastic / Q000235:genetics / Q000628:therapy*; D016026:Bone Marrow Transplantation; D002648:Child; D002678:Chimera / Q000235:genetics*; D004247:DNA / Q000737:chemistry*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D018598:Minisatellite Repeats; D016133:Polymerase Chain Reaction
D004247:DNA