LBP32: FETAL MICROCHIMERISM IN DEVELOPING OF ACUTE GVHD AFTER HAPLOIDENTICAL BMT

Abstract

Aim One of the possible therapeutic approaches in patients without a HLA-identical donor is the haploidentical transplantation (haplo-BMT). However, one of the major complications in haplo-BMT is a high probability of GVHD developing. Currently there is data concerning the relationship between the maternal microchimerism level (detection of maternal cells in recipient’s blood) and increase the of the probability of GVHD developing. At the same time, the influence of fetal microchimerism on the probability of developing GVHD is contradictory. The aim of our study was to develop a method of quantitative of fetal (recipient’s) microchimerism detection and thei role of major complications haplo-BMT assessment. Methods Determination of microchimerism was carried out by real-time alle-specific polymerase chain reaction (AS RQ-PCR). We used 20 SNP markers for analysis located at different chromosomes. Evaluation of the PCR sensitivity was carried out by mixing of the cell lines DNA (HL60, K562 , 293T, MOLT3, A549) at serial dilutions . Samples were analyzed from 11 donor-recipient pairs . The age of patients ranged from 2 to 27 years. Results The sensitivity of the developed SNP-based test-system ranged from 10 −4 to 10 −5 . We found out no effect of age of the recipient on the quantitative values of fetal microchimerism ( p = 0.96). There was also no relationship between graft failure and fetal microchimerism level ( p = 0.34). However, we determined reduced probability of acute GVHD in patients where they donors were mother with higher levels of fetal microchimerism (Mann–Whitney t -test: Z = −2.54, p = 0.01). Conclusion Evaluation of fetal microchimerism may be recommended as one of the factors when choosing a method of GVHD prevention in haploidentical BMT.