LAUSR

To the Editor: This study reported that a case of Philadelphia chromosome-positive B-acute lymphoblastic leukemia (Ph B-ALL) underwent a lineage switch to acute myeloid leukemia (AML) following CD19 chimeric antigen receptor (CAR)-modified T (CAR-T) cells therapy. The study was reviewed and approved by the ethics committee of the first affiliated hospital of Nanjing Medical Universit (No. 2020QT-06). A 46-year-old woman with a 1-month history of chest painwas admitted to our hospital on January 24, 2014. The resultsofher laboratory examinationswereas follows: (i) White blood cell count 12.01 10/L; hemoglobin 92 g/L; platelet count 47 10/L; (ii) Bone marrow (BM) smears showed a massive infiltrate (95.2%) of blast cells; (iii) Immunophenotypic analysis by flow cytometry (FCM) revealed that blast cells accounted for 66.3%, which were positive for CD34, CD10, CD19, CD20, CD22, CD38, and human leukocyte antigen DR; (iv) Karyotype analysis showed no mitotic phase; (v) Fluorescence in situ hybridization demonstrated a positive Philadelphia chromosome (BCR-ABL fusion gene); (vi) BM quantitative real-time polymerase chain reaction (qRT-PCR) detected a positive BCR-ABL p190 transcript (BCR-ABL, 184.1%). She was thus diagnosed with Ph B-ALL.