ZAP-70 expression is low in normal precursor B cells or hematogones

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• Zeta-associated protein (ZAP-70) expression correlates with a poorer prognosis in chronic lymphocytic leukemia (CLL).
• The function of ZAP-70 in immature B-cells remains unclear.
• Immature B-lymphocytes, or hematogones, are common in clinical samples and express CD10, CD38, and CD19.

Purpose of the Study:

• To investigate the role of ZAP-70 expression in the spectrum of B-cells found in clinical specimens.
• To determine if ZAP-70 is expressed in hematogones.

Main Methods:

• Evaluated ZAP-70 expression in 25 patient samples with significant CD10(+)/CD38(bright)/CD19(+) coexpression.
• Assessed ZAP-70 levels in CD38(bright)/CD19(+) coexpressing cells using routine clinical testing methods for CLL.
• Hematogone expression ranged from 2-18% of total leukocytes across various conditions.

Main Results:

• ZAP-70 was consistently absent in CD5-negative, CD38/CD19 coexpressing precursor B-cells (hematogones).
• Hematogones did not exhibit significant ZAP-70 expression in any of the cases studied.

Conclusions:

• The presence of hematogones in clinical samples must be acknowledged.
• Failure to recognize hematogones could negatively impact prognostic assessments of ZAP-70 and CD38 in CLL patients.