Haploidentical bone marrow transplantation in leukemia and genetic diseases

From 1986 to June 2000, sixty children suffering from acute and chronic leukemia (n = 42, 33 of which in resistant relapse), genetic diseases (n = 11), aplastic anemia (n = 2, one of which with platelet refractoriness and bleeding), myelodysplasia (n = 5) received an haploidentical bone marrow, mismatched for 2-3 HLA loci. The donor's marrow was treated in vitro with vincristine and methylprednisolone to obtain a functional T depletion (MLC and CTL inhibition, functional blockade of Th1 and Th2). The prevalence of infectious complications and GVHD was similar to that recorded in matched unrelated donor (MUD) transplants. In situations of high risk of rejection (chronic leukemia, genetic diseases) we infused immediately one half of the harvest and then frozen aliquots from the second week. Of the 25 ALL and 8 AML in resistant relapse, 3 survived, disease-free at 14, 8 and 1 years respectively. Of the 3 ALL, transplanted during remission, 1 is surviving at 18 months. Of the 6 CML, 1 had fractionated bone marrow and is surviving at 3 years, and 5 had standard single dose infusion and died of progression of their disease after rejection of the graft (4) or blast crisis after complete engraftment (1). The 2 patients with aplastic anemia, those with myelodysplasia, and 6 of the 10 with genetic disorders died of transplant-related complications or disease progression. 4 patients with osteopetrosis (n = 2), MLD (n = 1), Wiskott Aldrich dis. (n = 1) survive at 8, 2, 5 and 1.5 years respectively. In patients transplanted with fractionated marrow GVHD > 2nd grade occurred in 15%. Only one patient rejected the graft. Compared with MUD transplantation, mismatched BMT whenever performed in patients in good conditions provides similar outcome and widens the donor availability.