Assessment of hematopoetic stem cell molecular engraftment based on STR analysis
Saniya A. Abdrakhmanova, Zhulduz Zh. Zhanzakova, Aida A. Turganbekova, Zhazira K. Saduakas
Scientific Production Center of Transfusiology, Ministry of Healthcare, Nur-Sultan, Republic of Kazakhstan
Contact: Dr. Saniya A. Abdrakhmanova
Donor chimerism monitoring is the main way to control the process of hematopoietic engraftment. Assessment of the engraftment course in oncohematological patients is important for the choice of treatment strategy and further management of the patient.
Patients and methods
In order to assess engraftment, 38 patients with oncohematologic diseases were analyzed who underwent 38 hematopoietic stem cell transplantations (HSCT) from 2017 to 2019, including 13 women (34%) and 25 men (66%). The median age at the time of transplantation was 33 (2-47) years. The gender distribution among donors was 19 women (50%), and 19 males (50%). The patients were divided into two groups: 26 patients (68%) after allogeneic compatible HSCT (allo-HSCT), and 12 patients (32%), after haploidentical HSCT (haplo-HSCT). The donor chimerism was determined by polymerase chain reaction of short tandem repeats (STR-PCR) in peripheral blood on days +30, +60, and +100 after HSCT. The study was conducted more frequently in cases of mixed chimerism detection. For amplification of STR markers, the commercial AmpFlSTR® Identifiler® Plus Kit (UK) kit was used; PCR products were separated by capillary electrophoresis on a 3500 Genetic Analyzer (HITACHI Applied Biosystems, Japan). The alleles were identified using the Chimer Marker v3.1.0 software.
Concerning ratios of donor/recipient pairs, the female donor/male recipient combinations (15 pairs), and male donor/male recipient transplants (13 pairs) were more common than male donor/female recipient and female donor/female recipient combinations. When assessing the stem cell engraftment, all markers were informative for the studied donor/recipient pairs. According to the degree of significance, the loci in the allo-HSCT pairs were distributed as follows: D13S317 / D18S51> D5S818 / D16S539 / D21S11 /D7S820> TH01 / AMEL / FGA / D8s1179 / D2S1338> CSF1PO / D3S1358 / TPOX> D19S433 / W19A. The numbers of informative genetic loci in the donor/recipient pairs varied from 4 to 13. For haplo-HSCT pairs, the distribution of loci was as follows: D13S317 / D7S820 / AMEL> D16S539 / D2S1338 / D18S51> D5S818 / FGA>D8s1179 / D21S11 / CSF1PO / D3S1358 / VWA> D19S433> TH01 / TPOX, with 1 to 8 informative loci. According to the results of our analysis, complete donor chimerism (99-100%) in haplo-HSCT was found in 2 patients (18%) on the day +30 after HSCT, according to HLA matching degree of 5/10 and 6/10; the remaining ten cases showed mixed chimerism. On day +100, 2 out of 10 reached full donor chimerism. Complete chimerism was revealed in 11 pairs with allo-HSCT, among them, the HLA matching degree was 10/10 in 9 pairs, and 5/10, in two pairs. By 100 days, 3 patients developed a transition from mixed to complete chimerism.
The analysis showed an association between HLA typing results, and the type of performed HSCT (allo- or haplo-HSCT). Chimerism monitoring after transplantation is an integral part of more effective prognosis for relapse and factor of improved survival for the patients after HSCT.
Chimerism, engraftment, hematopoietic stem cell transplantation, STR loci.