Abstract:

Objective To provide evidences for clinical diagnosis and treatment of lineage switch from acute myeloid leukemia (AML) to acute lymphoblastic leukemia (ALL) by exploring clinical features of the disease. Methods The clinical data, diagnosis and treatment process of one patient whose lineage switch from AML-M5b to B-ALL were retrospectively analyzed, the relevant literature was reviewed. Results A 4-year-old girl presented with a 5-day history of fever and abdominal pain. The medical history, physical examination and auxiliary examination of the patient suggested a diagnosis of AML-M5. Complete remission (CR) of hematology and cytogenetics was achieved after induction chemotherapy. However, one year later, disease relapsed, the morphologic and immunophenotypic features were consistent with B-ALL. She achieved CR again by adoptive immunotherapy using chimeric antigen receptor expressing T cells (CAR-T). But soon, the disease relapsed again, the second CAR-T treatment was ineffective, and the child died. Conclusion Our case suggests that lineage switch heralds a dismal clinical outcome. Therapy appropriate for the leukemic phenotype at the time of lineage switch may be advisable. For the cases in which the cell lineage switched from AML to B-ALL and CD19 is expressed, the patient may acquire CR again by CAR-T cell therapy but it is prone to secondary recurrence. Clinically, for recurrent leukemia, it is necessary to improve the detection of morphology, immunology, next generation sequencing, chromosome karyotype and other aspects of cytogenetics and molecular biology, so as to better guide the treatment and evaluate the prognosis.

Key words: leukemia, myeloid, acute, precursor cell lymphoblastic leukemia-lymphoma, lineage switch, chimeric antigen receptor-T cell therapy