Atypical mixed lymphocyte culture. Identity between mother and child in leukemia and aplastic anemia

The mixed lymphocyte culture tests between one patient with acute lymphocytic leukemia and her mother and between another patient with aplastic anemia and his mother were found nonreactive, despite a one-haplotype difference for HL-A. Two crossovers in each family at the MLC locus or a specific defect in lymphocyte responsiveness could be possibly explantations. The mother of each patient could be considered a potential donor for bone marrow transplantation.