DETECTION OF CBF-BETA MYH11 FUSION TRANSCRIPTS IN PATIENTS WITH INV(16) ACUTE MYELOID-LEUKEMIA AFTER ALLOGENEIC BONE-MARROW OR PERIPHERAL-BLOOD PROGENITOR-CELL TRANSPLANTATION/

We evaluated the occurrence of the CBF beta/MYH11 fusion transcripts b y PCR analysis in 10 patients with inv(16)(p13;q22) acute myeloid leuk emia (AML) who underwent allogeneic bone marrow transplantation (BMT) (n = 5), peripheral blood progenitor cell transplantation (PBPCT) (n = 3), or autologous transplantation (n = 2), In addition to the analysi s of minimal residual disease (MRD), the chimerism status of patients after allogeneic transplant was studied by PCR, The CBF beta/MYH11 fus ion trancript was not detectable in six of seven patients who remained in remission after allogeneic BMT or PBPCT, Two of these patients in remission were monitored for 50 months and 64 months post-BMT, One pat ient in remission was PCR-positive for CBF beta 3 months post-BMT in a single BM sample, but not in a simultaneously examined blood sample, suggesting that analyses from BM samples are more sensitive than those from blood samples, Sequential PCR assays performed 6 and 12 months p ost-BMT obtained from the same patient mere negative, Another patient with a positive PCR assay 3 months post-allogeneic PBPCT, remained PCR positive for the CBF beta/MYH11 fusion transcript when tested 6 month s post-PBPCT. A chimerism analysis by PCR revealed a mixed chimerism s tatus in this patient, He relapsed 7 months post-transplant, Before tr ansplant, in all nine patients who were in complete remission of AML ( eight patients in 1CR, one patient in 2CR), the CBF beta/MYH11 transcr ipt was detectable, In one patient in relapse, the fusion transcript w as not only detectable in blood and bone marrow, but also in a cerebro spinal fluid sample prior to transplant, Two patients who received aut ologous BMT were monitored for CBF beta/MYH11 transcripts 3 months aft er BRIT, The CBF beta\MYH11 was detected in these patients, Both. pati ents subsequently relapsed 3 months and 23 months post-autologous BMT, The results study show that analysis of the CBF beta/MYH11 fusion tra nscript by PCR seems to be a suitable method for monitoring minimal re sidual disease in AML patients with inv (16).