Cure of aplastic anaemia in paroxysmal nocturnal haemoglobinuria by marrow transfusion from identical twin: Failure of peripheral-leucocyte transfusion to correct marrow aplasia.

The ability of syngeneic peripheral leucocytes to cure marrow aplasia was tested in a patient with paroxysmal nocturnal haemoglobinuria (P.N.H.). Transfusion of 7.1X10(10) white cells obtained by leucopheresis from an identical-twin donor, providing 3.4X10(4) myeloid progenitors (C.F.U.-C)/kg, failed to improve marrow function within two months. In contrast, transfusion of 1.3X10(10) nucleated bone-marrow cells, representing 6.4X10(4) C.F.U.-C/kg, from the same donor resulted in prompt bone-marrow recovery. These observations support the hypothesis that aplastic anaemia in P.N.H. is a stem-cell defect that may be corrected by the simple infusion of relatively small numbers of normal bone-marrow cells. They also seem to indicate a distinct advantage of marrow cells over peripheral-blood mononuclear cells in their ability to correct marrow aplasia.