Abstract: Several methods have been developed to determinate
genetic profiles from a mixed samples and chimerism
analysis in transplanted patients. The aim of this study was
to explore the effectiveness of using the droplet digital PCR
(ddPCR) for mixed chimerism detection (a mixture of genetic
profiles resulting after allogeneic hematopoietic stem cell
transplantation (HSCT)).We analyzed 25 DNA samples from
patients who had undergone HSCT and compared the performance
of ddPCR and two established methods for chimerism
detection, based upon the Indel and STRs analysis, respectively.
Additionally, eight artificial mixture DNA samples were
created to evaluate the sensibility of ddPCR. Our results show
that the chimerism percentages estimated by the analysis of a
single Indel using ddPCR were very similar to those calculated
by the amplification of 15 STRs (r2 = 0.970) and with the
results obtained by the amplification of 38 Indels (r2 = 0.975).
Moreover, the amplification of a single Indel by ddPCR was
sensitive enough to detect a minor DNA contributor comprising
down to 0.5 % of the sample. We conclude that ddPCR
can be a powerful tool for the determination of a genetic profile
of forensic mixtures and clinical chimerism analysis when
traditional techniques are not sensitive enough.