Grading of follicular lymphoma using flow cytometry

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• Follicular lymphoma (FL) grading is crucial for treatment and prognosis.
• Current histological grading methods are subjective and difficult in small biopsies.
• Accurate grading is essential for classifying FL into low (grades 1-2) and high (grade 3) categories.

Purpose of the Study:

• To evaluate the utility of flow cytometry (FCM) for grading follicular lymphoma.
• To determine if CD19/forward scatter analysis can differentiate low-grade from high-grade FL.
• To establish a more objective and reproducible method for FL grading, particularly in small tissue samples.

Main Methods:

• Retrospective analysis of 36 follicular lymphoma cases undergoing FCM.
• Evaluation of the percentage of cells beyond the 500-channel mark on CD19/forward scatter dot plots.
• Comparison of FCM findings with histological grading from open biopsies.

Main Results:

• A significant difference in the percentage of cells beyond the 500-channel mark was observed between low-grade and high-grade FL (median 4.9% vs. 21%, P=0.00001).
• The percentage of these cells ranged from 0.12% to 12.55% in low-grade FL and 6.22% to 51.95% in high-grade FL.
• This FCM parameter showed a strong correlation with the established histological grade.

Conclusions:

• Flow cytometry with CD19/forward scatter analysis can reliably identify centroblasts in follicular lymphoma.
• FCM offers a viable method for grading FL, overcoming limitations of traditional histology in small biopsies.
• This technique improves diagnostic accuracy and aids in clinical decision-making for FL patients.