The role of immunophenotyping in differential diagnosis of chronic lymphocytic leukemia

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• Accurate diagnosis of chronic lymphocytic leukemia (CLL) relies on immunophenotyping via flow cytometry for differential diagnosis from other mature B-cell neoplasms (MBCN).
• Distinguishing CLL from MBCN is crucial for appropriate patient management and treatment strategies.

Purpose of the Study:

• To define the specific immunological profile of CLL cells.
• To establish a reliable method for differentiating CLL from other MBCN using flow cytometry.

Main Methods:

• Immunophenotyping by flow cytometry was performed on peripheral blood samples from 211 patients diagnosed with de novo MBCN.
• Analysis included B-cell counts, surface immunoglobulin light chain restriction, and expression of various B-cell antigens (CD19, CD20, CD22, CD5, CD23, FMC7, CD79b).
• A CLL scoring system was utilized to correlate with diagnostic outcomes.

Main Results:

• B-cell counts were significantly elevated in MBCN patients compared to healthy controls.
• B-cell monoclonality was detected in 96% of MBCN patients.
• CLL cells exhibited a distinct immunophenotype: CD19+, CD20(low), CD22(low), CD5(high), CD23+, FMC7-, CD79b(low), and sIg(low).
• A CLL score of 5 or 4 strongly indicated CLL (97% of CLL patients), while scores of 0-3 suggested other MBCN (96% of other MBCN patients).

Conclusions:

• A characteristic immunophenotype (CD19+ CD20low CD22low CD5high CD23+ FMC7- CD79blow sIglow) effectively differentiates CLL from other MBCN.
• The CLL scoring system, with scores of 4 or 5, is highly suggestive for diagnosing CLL.
• These findings enhance the accuracy of CLL diagnosis through flow cytometry immunophenotyping.