Long-term production of pre-existing alloantibodies to E and c after allogenic BMT in a patient with aplastic anemia resulting in delayed hemolytic anemia.
BACKGROUND
Delayed hemolysis mediated by long-term production of pre-existing recipient-derived antibodies directed against donor RBC antigens after allogenic BMT is an unusual complication of hematopoietic transplantation.


METHODS
A 26-year-old man with aplastic anemia had pre-existing alloantibodies to E and c. He received BMT from a donor, whose Rh phenotype was E+, c+. From about 1 month after the transplant, he showed mild hemolysis due to the antibodies.


RESULTS
The patient was typed as group B, CCDee and had anti-E and c alloantibodies before BMT. The donor was typed as group O, ccDEE. Although MNCs from the donor marrow were infused into the patient, DAT became positive on Day 21, and the patient-origin antibodies remained detectable by both DAT and IAT even 20 months after BMT. However, immunomagnetically isolated peripheral circulating B cells were 100 percent donor origin. The patient received prednisolone from Day 221, and thereafter, the signs of hemolysis disappeared.


CONCLUSIONS
It is likely that the long-term production of alloantibodies is due to the existence of long-lived recipient plasma cells, which survive the conditioning regimen. This case suggests that patients with pre- existing alloantibodies that do not belong to the ABO system should be carefully followed up after BMT.
Izumi
Noriko
N
First Department of Internal Medicine, Niigata University School of Medicine, Niigata, Japan.
Fuse
Ichiro
I
Furukawa
Tatsuo
T
Uesugi
Yumiko
Y
Tsuchiyama
Junjiro
J
Toba
Ken
K
Togashi
Kazue
K
Yamada
Keiko
K
Ohtake
Sachiko
S
Saitoh
Yukiko
Y
Yanagisawa
Naoe
N
Aizawa
Yoshifusa
Y
D000017:ABO Blood-Group System / Q000276:immunology*; D000328:Adult; D000741:Anemia, Aplastic / Q000628:therapy*; D000743:Anemia, Hemolytic / Q000209:etiology / Q000276:immunology*; D000917:Antibody Formation; D016026:Bone Marrow Transplantation; D006801:Humans; D007518:Isoantibodies / Q000097:blood*; D008297:Male; D065227:Transfusion Reaction; D014184:Transplantation, Homologous
D000017:ABO Blood-Group System; D007518:Isoantibodies