بررسي كينتيك كايمريسم در گيرندگان پيوند مغز استخوان با استفاده از تكثير لوكوس هاي ژني اس تي آر با روش پي سي آر مالتيپلكس

Kinetics of chimerism after bone marrow transplantation by multiplex PCR amplification of short tandem repeat (STR) gene loci

Background: Bone marrow transplantation (BMT) has an increasing application in most of the hematological disorders that cannot be controlled by current chemotherapy strategies. Therefore, the ability of evaluation of the contribution of donor cells in recipientsʹ blood circulation (chimerism) is important in the kinetics of bone marrow engraftment. The present study was carried out on candidates of BMT at Tehran Shariati hospital in order to evaluate post transplantation kinetics of chimerism by multiplex polymerase chain reaction. Materials and Methods: This descriptive study was performed on 360 blood samples from ten patients who underwent blood or bone marrow stem cell transplantation. Six of the patients were suffering from different types of leukemia and four patients had non- malignant hematological disorders. The chimeric status of transplantation was investigated by close molecular monitoring up to six months post transplantation. Donor and recipient allelic patterns were determined by multiplex PCR using a panel of STR gene markers such as ARA, D4S2366, D16S539, D7S820, D13S317, F13A1, FESIFPS, VWA, CSFIPO, TPOX and TH01 on DNA of blood specimens. Result: Based on different gene loci a sensitivity of 1-2% was obtained using PCR method. Mixed chimerism was detected in all the patients between days 1 to 9 post transplantation. Eight patients changed to a complete allelic pattern during the days 9 to 14 and had an uncomplicated post transplant disease course. Two patients including one with low intensity conditioning regimen consistently retained mixed chimerism up to six months. Most of the patients achieved full chimerism between days nine to fourteen. Hematological and platelet engraftment occurred between days 8-9 and 9-25 post transplantation respectively. Conclusion: The data show that STR analysis using multiplex PCR can provide an accurate, rapid and quantitative assessment of chimerism situation in post transplantation patients. Such information may be useful for guiding early implementation of additional treatment designed to circumvent graft failure or suppression of relapse in the future.