Refining the Limits of Borderline Lymphoproliferative Disorders

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• The definition and classification of borderline lymphoproliferative disorder (LPD) lack clarity.
• Accurate diagnosis of LPD is crucial for appropriate patient management and treatment strategies.

Purpose of the Study:

• To classify patients with leukemic LPD into chronic lymphocytic leukemia (CLL) or non-CLL categories.
• To evaluate the efficacy of diagnostic strategies including D'Arena and CLLflow scores and CD43 expression.
• To characterize patients with unclassified or borderline LPD.

Main Methods:

• A cohort of 597 patients with leukemic LPD (excluding specific subtypes) was analyzed.
• Three diagnostic strategies were applied: D'Arena score, CLLflow score, and CD43 expression.
• Discordant cases and borderline LPD were further investigated using cytometric markers and cytogenetic data.

Main Results:

• The CLLflow score demonstrated the highest accuracy among the three strategies when excluding borderline LPD.
• The addition of CD43 expression to the diagnostic strategies eliminated misclassifications.
• 16 patients (2.7%) were classified as borderline LPD and could not be definitively diagnosed by any single strategy.
• Hierarchical clustering suggested two antigenic groups within the borderline LPD cohort.

Conclusions:

• The combination of CLLflow score and CD43 expression offers high diagnostic accuracy for leukemic LPD.
• Current diagnostic strategies are insufficient for reliably identifying or diagnosing borderline LPD.
• Borderline LPD represents a distinct entity requiring further investigation into its biological characteristics.