Long-term culture and molecular biological studies highlight differences in relative BCR-ABL expression levels in the peripheral blood and bone marrow of a patient with chronic granulocytic leukaemia

Abstract

A patient with accelerating Ph + ve chronic granulocytic leukaemia (CGL) was considered for autologous BMT using marrow 'purged' by 4 weeks long-term culture (LTC). Efficacy of purging was determined using reverse transcriptase PCR for BCR-ABL mRNA transcripts b2a2 and b3a2. Peripheral blood and bone marrow were compared. Three observations emerged: (i) the initial b2a2:b3a2 ratios for unmanipulated blood and marrow were different with values of 9:1 and 2:1 respectively; (ii) both transcripts were successfully 'purged' with LTC of blood but not marrow; and (iii) LTC of marrow caused a transient increase in relative levels of b3a2 mRNA and a corresponding reduction in the b2a2 signal. This is the first case where such differences have been demonstrated in association with LTC.