Boy battling acute lymphoblastic leukemia

Patient's Basic Information

A 16-year-old male diagnosed with acute lymphoblastic leukemia (B-ALL), who underwent initial chemotherapy, CD19/22 CAR-T cell therapy, salvage chemotherapy, and subsequent haploidentical allogeneic hematopoietic stem cell transplantation (allo-HSCT) from a parental donor.

Patient's Pre-Treatment Situation

Prior to allo-HSCT, the patient experienced rapid white blood cell proliferation and persistent disease despite multiple interventions. Following CD19/22 CAR-T infusion on April 21, 2025 (total CAR-T cells: 6.5×10^7), CAR-T cell counts initially expanded to 3.95×10^6/L by day 7 but declined to 0.82×10^6/L by day 14, with peripheral blood blast cells rising from 28.6% to 87.1%. Bone marrow examination on May 15, 2025, revealed severely reduced proliferation with 37.42% abnormal B lymphoblasts (expressing CD34, partial CD38/CD22, weak CD81/CD19/CD33, no CD10/CD20/CD79b), confirming no remission. Cerebrospinal fluid showed no abnormal cells, but the overall disease remained unrelieved.

Patient's Post-Treatment Situation

After allo-HSCT on May 29-30, 2025 (CD34+ cells: 8.6×10^6/kg; mononuclear cells: 8×10^8/kg), the patient achieved neutrophil engraftment by day 11 and platelet engraftment by day 18. By day 28 (June 27, 2025), blood counts improved significantly: hemoglobin 99 g/L (from prior low levels), white blood cells 11.73×10^9/L, neutrophils 9.81×10^9/L, and platelets 79×10^9/L. Bone marrow morphology showed active proliferation with no abnormal primitive cells, flow cytometry confirmed no anomalies, biopsy indicated low proliferation but visible trilineage cells without immature lymphocytes, and STR chimerism reached 100%, achieving complete remission (CR) with minimal residual disease negative (MRD-). By day 49 (July 18, 2025), bone marrow remained active with no abnormal cells, sustaining CR and MRD-. Mild grade 1 intestinal graft-versus-host disease occurred but was managed with medications, demonstrating effective disease control and recovery compared to pre-transplant persistent blasts (from 37.42% to 0%) and lack of remission.