B-cell activating factor receptor expression in B-lymphoblastic leukaemia: Flow cytometric analysis and implications...

Area of Science:

• Immunology
• Hematology
• Oncology

Background:

• Cluster of differentiation 19 (CD19)-targeted therapies are effective for B-cell malignancies but face challenges from antigen escape and relapse.
• The B-cell activating factor receptor (BAFF-R) is crucial for B-cell survival and highly expressed in mature B-cell neoplasms, but its role in B-cell acute lymphoblastic leukemia (B-ALL) is not well understood.

Purpose of the Study:

• To investigate BAFF-R expression in B-ALL, particularly in relapsed cases with CD19-negative antigen escape.
• To evaluate BAFF-R as a potential therapeutic target in B-ALL, especially in challenging relapse scenarios.

Main Methods:

• Multi-parameter flow cytometry was used to assess BAFF-R expression in diagnostic and relapsed B-ALL samples.
• Analysis included correlation of BAFF-R expression with CD19 status and tumor protein p53 (TP53) alterations.

Main Results:

• BAFF-R was consistently expressed in most B-ALL cases, though at lower levels than in mature B cells.
• BAFF-R expression was retained in most CD19-negative relapses, a group significantly enriched for TP53 alterations (68.8%).
• BAFF-R remained expressed even in CD19-negative, TP53-altered B-ALL, indicating its stability as a target.

Conclusions:

• BAFF-R is a stable immunotherapeutic target in B-ALL, including CD19-negative and TP53-altered relapsed disease.
• These findings support the ongoing clinical trials of BAFF-R-directed chimeric antigen receptor (CAR) T-cell therapy for B-ALL.