CLL immunophenotype scoring system

CLL immunophenotype scoring system

Definition and key markers

• typical B-cell CLL immunophenotype: characterized by co-expression of CD5, CD19, CD23 with weak monotypic surface immunoglobulin (sIg), and weak or absent FMC7, CD22, or CD79b (1,2)
• diagnostic utility: an immunophenotypic scoring system (Matutes score) differentiates chronic lymphocytic leukaemia (CLL) from other mature B-cell lymphoproliferative disorders (1)
• score interpretation:
  • typical CLL: score of 4 or 5 (seen in ~92% of cases) (1)
  • atypical CLL: score of 3 (seen in ~6% of cases) (1)
  • non-CLL B-cell malignancies: usually score 0, 1 or 2 (a small minority score 3) (1,2)

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Role of CD200 in Refining Diagnosis

• CD200 expression: highly and uniformly expressed on CLL cells, but characteristically absent or weak in mantle cell lymphoma (MCL) (3)
• modified Matutes score: inclusion of CD200 (score = 1 if positive) increases diagnostic accuracy, sensitivity, and specificity in differentiating CLL from non-CLL lymphoproliferative disorders, particularly resolving ambiguity with MCL (3,4)

Table 2. Diagnostic Performance Comparison

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Key points:

• CD200 serves as a robust addition to flow cytometry panels for resolving diagnostic ambiguity between CLL and mantle cell lymphoma (3,4)
• a modified Matutes score incorporating CD200 enhances sensitivity while maintaining high specificity across clinical laboratory settings (3)

References:

1. Oscier D et al. Guidelines on the diagnosis and management of chronic lymphocytic leukaemia. Br J Haematol. 2004;125(3):294-317.
2. Moreau EJ, Matutes E, A’Hern RP, Morilla AM, Morilla RM, Owusu-Ankomah KA, et al. Improvement of the chronic lymphocytic leukemia scoring system with the monoclonal antibody SN8 (CD79b). Am J Clin Pathol. 1997; 108(4):378-82.
3. Yee KW, O'Brien SM. Chronic lymphocytic leukemia: diagnosis and treatment. Mayo Clin Proc. 2006;81(8):1105-29.
4. Jalal SD. The contribution of CD200 to the diagnostic accuracy of Matutes score in the diagnosis of chronic lymphocytic leukemia in limited resources laboratories. PLoS ONE 2021 16(2): e0247491. https://doi.org/10.1371/journal. pone.0247491.