RESUMO
Seventy-three unrelated Saudi individuals and seven consecutive bone marrow transplant donor-recipient pairs were studied to characterize and determine the frequency of 3 apolipoprotein B alleles by polymerase chain reaction. The samples analyzed were either peripheral blood or bone marrow aspirates. Eleven different alleles were detected. The index of heterozygosity was 0.66. Apolipoprotein B analysis was informative in 57% of the studied donor-recipient pairs. Engraftment was detected as early as day three post-transplantation. The threshold of detection of this allele was up to 0.01xl0[6]/ml. Mixed chimerism of the order of 1% could be detected. We concluded that apolipoprotein B is a highly polymorphic allele among the Saudi population and this makes the region a useful marker for monitoring engraftment following allogeneic bone marrow transplantation