Objectives: New B-cell markers are needed for monitoring B lymphoblastic leukemia (B-ALL) in the era of immunotherapies directed against CD19 and CD22. The expression of leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1) on hematogones in bone marrow (BM) and neoplastic B lymphoblasts has not yet been systematically investigated.
Methods: We assessed LILRB1 expression pattern on B cells in 19 control BMs and 22 B-ALL cases by flow cytometry.
Results: In all cases, mature B cells and hematogones exhibited a consistent pattern of LILRB1 expression with variable intensity over different stages of maturation, including a characteristic V-shaped pattern on hematogones. While neoplastic B lymphoblasts in all cases expressed LILRB1, the pattern of expression was distinctly abnormal relative to hematogones (loss of the dynamic pattern in all cases and abnormal expression levels in 83% of cases).
Conclusions: LILRB1 is a novel diagnostic B-cell marker to aid in distinguishing neoplastic B lymphoblasts from hematogones.
Keywords: Anti-CD22; B-lymphoblastic leukemia; Flow cytometry; LILRB1; Minimal residual disease.
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