Description of an efficient and highly informative method for the evaluation of hematopoietic chimerism following allogeneic bone marrow transplantation.

The significance of full donor hematopoietic engraftment or hematopoietic chimerism (HC) following allogeneic bone marrow transplantation (BMT) remains unresolved. To study this phenomenon properly, informative genetic loci must be prospectively identified and followed for several years after allogeneic BMT in large numbers of consecutive patients treated with uniform conditioning and immunosuppressive regimens. In addition, sensitive methods that can be performed on small numbers of cells are required in order to extend the analysis for HC to individual hematopoietic lineages and specific anatomic compartments (eg bone marrow, peripheral blood, and lymph nodes). Although polymerase chain reaction (PCR) amplification of polymorphic minisatellite and microsatellite DNA loci has improved the sensitivity of detection of HC, a single rapid, sensitive, and highly informative test that can consistently distinguish donor from recipient elements for the majority of allogenic BMT patients has not been described. In the present report, we describe a single PCR that simultaneously amplifies four microsatellites and was able to identify an informative locus in 48 of 50 (96%) consecutive recipient/donor pairs. A HC of as little as 0.5% could be detected, and HC of 10% could be detected in as few as 100 cells. This technique should allow the detection of an informative microsatellite locus in most patients undergoing allogeneic BMT, using minimal amounts of DNA and requiring 16 h for completion.