system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, MATERIALS AND METHODS, RESULTS. Meshes: ABO Blood-Group System, Blood Donors, Blood Group Incompatibility, Blood Grouping and Crossmatching, Bone Marrow Transplantation, Erythrocytes, Follow-Up Studies, Humans, Leukemia, Myeloid, Acute, Male, Middle Aged, N-Acetylgalactosaminyltransferases, Transferases.
user
Can blood group O red cells of donor origin acquire weak group A reactivity through serum A transferase of the recipient after bone marrow transplantation? Context: Blood group A substance was detected on red cells of a patient who received a bone marrow transplant from a blood group O donor 3.5 years ago. Peripheral blood was investigated by conventional serological techniques, fluorescence in situ hybridisation, and polymerase chain reaction. All peripheral blood cells are of donor origin. Anti-A and not anti-A, B of blood group O individuals can be absorbed to the group O red cells of the patient.
assistant
We suppose that the patient's residual serum A transferase attaches the appropriate sugar to substance H on the red cell membrane to form substance A.