Fluorescence in situ hybridization (FISH) was employed to confirm engraftment and lo check chimerism and the predictive value of recipient cells on relapse at different time-points in 43 sex mismatched allo-BMT. The 43 pts, who received an allo-BMT from an opposite sex donor were studied in the period September '94- Febraury '96 Data were analyzed as of March "96 FISH was always performed on bone marrow (BM). The Y chromosome probe (Yql2) was labelled with biotm and coloured in green, and the X chromosome probe (Xcen ) was labelled with digoxigenin and coloured in red. The reproducibility of the tecnique was confirmed by the analysis of 16 samples from 4 BMT recipients that were examined four times each and that showed a little range of variation for XX and XY interphase cells even when the proportion of these cells was small. In 20 donors the upper boundary of 95% confidence intervals, obtained by using a binomial distribution, was employed to establish the probability of detecting 0,1,2,3,XX cells in males or XY cells in females. In this way we succeeded in fixing the normal range of XX cells in males up to 0 6% and of XY cells in females up to 0.2%. By comparing the number of XX and XY cells in each transplant specimen with these normal ranges we found an elevated number of XX cells in the 27 males and of XY cells m the 16 females submitted to allo-BMT Therefore the proposed cut-offs yeld a sensitivity of 100%.In situ assay was performed in the first 100 days posttransplant in 32/43 pis. FISH gave informative results m all cases examined,even in 5 with marrow hypoplasia. In CR pts the average number of host cells was 4.4% ( range 0 to 67.3%), in relapses it was 12.3% (range 0.3 to 71.3) From 101 days lo one year after allo-BMT these percentages were 0.69% (range 0 to 6%) and 18.8% (range 0 to 89.6%). In 8 patients in CR at long post-transplant intervals (407 days - 3 years I the percentage of host cells was 0.6%. By applying statistical tests we found that the number of host cells does not predict relapse in any of these time-points after allo-BMT However a trend towards statistical significance emerges after 365 days (P=0.6), Our data show that FISH is a reliable technique to study chimerism in sex-mismatched allo-BMT and that the presence of host cells even at long posttransplant intervals does not herald relapse.
|Number of pages||1|
|Publication status||Published - 1996|
ASJC Scopus subject areas
- Cancer Research
- Cell Biology