PML-RAR-ALPHA PCR POSITIVITY IN THE BONE-MARROW OF PATIENTS WITH APL PRECEDES HEMATOLOGICAL RELAPSE BY 2-3 MONTHS

We report the results of serial tests in three patients with hyperleuc ocytotic AML M3 by haematological methods, coagulation assays and PCR analyses following treatment with ATRA and chemotherapy. All three pat ients became PCR negative in bone marrow and peripheral blood (sensiti vity level 1 in 10(5) cells) after one cycle of ATRA+ chemotherapy. Ho wever, they relapsed haematologically 6-9 months after achieving compl ete haematological remission. The haematological relapse was preceded by PCR positivity in the bone marrow by 3 months. Platelet counts decr eased already during CHR, but dropped below normal levels only at the time of relapse. Coagulation parameters were not helpful for early pre diction of relapse. Our results demonstrate that PCR analysis in the b one marrow is the best way to monitor patients with APL. However, in h yperleucocytotic patients, PCR negativity does not seem to indicate lo ng-term remission.