Monoclonal antibody 55 (CD10) and complement used for purging autologous bone marrow in common acute lymphoblastic...

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• Relapse in common acute lymphoblastic leukemia (C-ALL) is often linked to residual leukemic cells in autotransplants.
• Effective purging of these cells is crucial for improving patient outcomes.

Purpose of the Study:

• To evaluate the efficacy of a CD10 monoclonal antibody 55 (McAb55) for purging common acute lymphoblastic leukemia antigen (CALLA)-positive cells from C-ALL patient autotransplants.
• To standardize a protocol for bone marrow processing, purging, and preservation for C-ALL autotransplantation.

Main Methods:

• Bone marrow mononuclear cells (MNCs) were isolated using carboxymethyl starch sedimentation and Ficoll-Hypaque gradient separation.
• Cells were treated twice with McAb55 and complement to eliminate CALLA+ cells.
• Purged cells were preserved at room temperature for 48-72 hours before infusion.

Main Results:

• Two rounds of McAb55 and complement treatment removed 4-5 logs of CALLA+ cells, exceeding 99% removal.
• The procedure recovered 10-30% of MNCs while preserving hematopoietic stem cells.
• Four C-ALL patients receiving purged autotransplants showed timely hematopoietic recovery and remained in remission for 40-250 days.

Conclusions:

• McAb55-based purging is a highly effective method for eliminating residual leukemic cells in C-ALL autotransplants.
• The standardized protocol supports successful engraftment and sustained remission in C-ALL patients.
• This approach offers a promising strategy for improving the safety and efficacy of autologous stem cell transplantation in C-ALL.