Follow-up of 10 patients positive for BCR-ABL1^T315I by ASO PCR at inclusion. A systematic screening for presence of the T315I mutation at diagnosis was performed by ASO qRT-PCR in 43 patients and the T315I mutation was detected in 10 of them (23%). The kinetic of detection of the T315I mutation before relapse is indicated. Solid black circle, BCR-ABL1^T315I detected by ASO PCR; open gray circle, BCR-ABL1^T315I not detected by ASO PCR during follow-up. Allo, allogeneic; Post M, postmaintenance; R, relapse associated with BCR-ABL1^T315I detected by ASO PCR and Sanger sequencing.