Pretransfused patients with severe aplastic anaemia exhibit high numbers of cytotoxic T lymphocyte precursors probably directed at non-HLA antigens.
Patients with severe aplastic anaemia (SAA) have a relatively high risk of graft rejection after transplantation of bone marrow from HLA-identical siblings compared with patients transplanted for leukaemia. This is presumed to be due to pretransplant blood transfusions which sensitize the recipient's immune system to non-HLA antigens expressed on donor marrow cells. To test this hypothesis, we estimated in the peripheral blood of 18 SAA patients, the frequencies of alloreactive cytotoxic T lymphocyte precursors (CTL-p) directed against mononuclear cells from syngeneic twins, HLA-identical siblings or HLA-matched unrelated individuals. The results were compared with the frequencies of CTL-p in 13 healthy subjects or leukaemia patients who had not been transfused. Pretransfused patients with SAA had significantly higher frequencies of CTL-p directed against HLA-identical siblings (P = 0.002), and against HLA-matched unrelated individuals (P = 0.004), than did untransfused individuals. In contrast, the frequency of CTL-p in two pretransfused patients against syngeneic mononuclear cells was very low. We propose that the increased numbers of CTL-p in the blood of pretransfused SAA patients are directed against non-HLA antigens on target cells and may be the result of prior blood transfusion.
Kaminski
E R
ER
Department of Immunology, Royal Postgraduate Medical School, Hammersmith Hospital, London.
Hows
J M
JM
Goldman
J M
JM
Batchelor
J R
JR
D000741:Anemia, Aplastic / Q000097:blood / Q000276:immunology*; D000906:Antibodies / Q000032:analysis; D001853:Bone Marrow / Q000276:immunology; D016026:Bone Marrow Transplantation / Q000276:immunology; D004200:Diseases in Twins; D005260:Female; D006084:Graft Rejection / Q000276:immunology; D006680:HLA Antigens / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D065227:Transfusion Reaction
D000906:Antibodies; D006680:HLA Antigens