CD19 negative and dim precursor B-lineage acute lymphoblastic leukemias: real-world challenges in a targeted-immunotherapy era

Abstract

Flow cytometric diagnosis and minimal residual disease (MRD) assessment of precursor B-lineage acute lymphoblastic leukemia (B-ALL) are heavily dependent on CD19 based gating strategies. However, this approach is not optimal in the diagnosis and follow-up of CD19 negative or dim B-ALLs. Though CD19 negative B-ALLs are rare, in the current era of CD19 targeted immuno-therapy, CD19 negative B-ALL relapses are frequent. We have presented our cohort of 14 de novo CD19 negative and dim B-ALLs and have highlighted the difficulties faced during diagnosis and MRD assessment of these patients. We have also discussed the need to identify alternative B-lineage gating markers and strategies to deal with such scenarios.

Keywords:

• CD19 negative
• CD19 dim
• precursor B lineage
• acute lymphoblastic leukemia
• minimal residual disease

Acknowledgements

We would like to acknowledge Mrs. Arcot Radhakrishnan Abitha, senior scientific assistant, for her efforts in flow cytometry sample processing and acquisition. We would also like to thank Dr. Papagudi G. Subramanian and Dr. Prashant R. Tembhare from the hematopathology laboratory, Tata Memorial Center, Mumbai for their help in fine-tuning our flow cytometry assays for this manuscript.

Potential conflict of interest

Disclosure forms provided by the authors are available with the full text of this article online at https://doi.org/10.1080/10428194.2019.1625043.