Evaluation of Chimerism After Allogeneic Bone Marrow Transplantation Using Amplification of Hypervariable Regions of Human Genome by Polymerase Chain Reaction

Abstract

We used the polymerase chain reaction (PCR) as a novel and sensitive technique to evaluate posttransplant chimerism. Tandemly repetitive core sequences of regions with a variable number of tandem repeats (VNTR) served as genetic markers. Polymorphism of such loci results from allelic differences in the number of repeats. Primers flanking the repeat region of each of the corresponding VNTRs were used for amplification. Recipient and donor pretransplant DNA were amplified. The resultant fragments were analyzed after gel electrophoresis. Evaluation of four available cases indicated complete chimerism in three cases and mixed chimerism in one. The sensitivity of the method was determined by mixing various proportions of recipient and donor DNA; the limit of detection of the minor component in a mixture was 1%. PCR amplification of VNTR has advantages over other methods such as red blood cell phenotyping: high sensitivity, use of small amounts of blood or bone marrow, and the ability for early detection of posttransplant engraftment.