[Application of polymerase chain reaction for bone marrow transplantation]

Polymerase chain reaction (PCR) is a recently-developed technique capable of amplifying a specific nucleotide sequence and has been proved highly sensitive enough to analyse a small amount of DNA. This prompts us to study minimal residual disease (MRD) which is undetectable by conventional morphological or cytogenetic analysis. Using this technique, tumor specific chimeric DNA or mRNA were detected in patients with follicular lymphoma with t(14; 18) or in Ph1 positive ALL in complete remission, respectively. PCR was also useful to monitor MRD after treatment of bone marrow cells with monoclonal antibody. In sex-mismatched bone marrow transplantation, mixed chimerism was well documented by using repeated sequences which is unique to human Y chromosome. These results suggested that PCR offers a great help for detecting MRD or mixed-chimerism following bone marrow transplantation.