Two-color flow cytometry with a CD19 gate for the evaluation of bone marrow involvement of B-cell lymphoma
Chizuru Kawano-Yamamoto1, Kazuo Muroi, Thoru Izumi
1Division of Cell Transplantation and Transfusion, Jichi Medical School, Minamikawachi, Tochigi 329-0498, Japan. chizuru@jichi.ac.jp
Insights
Two-color flow cytometry with a CD19 gate (CD19-FCM) effectively detects clonal B-cells in bone marrow. This method aids in evaluating bone marrow involvement in B-cell lymphoma patients.
Area of Science:
- Hematology
- Immunology
- Oncology
Background:
- Clonal B-cells in bone marrow indicate B-cell lymphoma.
- Accurate detection is crucial for diagnosis and monitoring treatment efficacy.
Purpose of the Study:
- To evaluate the utility of two-color flow cytometry with a CD19 gate (CD19-FCM) for detecting clonal B-cells.
- To assess CD19-FCM's effectiveness in identifying bone marrow involvement in B-cell lymphoma.
Main Methods:
- Established normal kappa and lambda light chain ratios in adult bone marrow (0.5-3.0).
- Utilized CD19-FCM to analyze 99 bone marrow samples from 60 B-cell lymphoma patients, comparing results with histologic examination.
- Performed in vitro mixing experiments to determine detection sensitivity.
Main Results:
- CD19-FCM detected clonal B-cells when kappa/lambda ratios fell outside the 0.5-3.0 range.
- In vitro studies showed CD19-FCM could detect ≥10% clonal B-cells in normal bone marrow.
- Agreement between CD19-FCM and histology was 82% (81/99).
- Discrepancies (18/99) were mostly CD19-FCM positive and histology negative, with positivity often converting to negativity post-chemotherapy.
Conclusions:
- CD19-FCM is a valuable tool for detecting clonal B-cells in bone marrow.
- The technique shows promise for evaluating bone marrow involvement in B-cell lymphoma.
- CD19-FCM may offer sensitivity advantages over histology, particularly in monitoring treatment response.
Abstract:
The usefulness of two-color flow cytometry with a CD19 gate (CD19-FCM) for detecting clonal B-cells in the bone marrow was evaluated. Since kappa and lambda ratios analyzed in the bone marrow from healthy adults were within the range of 0.5-3.0, outside of this range was regarded as the existence of clonal B-cells. Mixing experiments in vitro showed that 10% or more of clonal B-cells contaminating normal bone marrow cells could be detected using CD19-FCM. Ninety-nine bone marrow samples from 60 patients with B-cell lymphoma were simultaneously analyzed using CD19-FCM and histologic examination of both bone marrow aspiration and core needle biopsy samples. The agreement of results obtained by both examinations was 82% (81/99). Discrepant results were found in 18 samples of 10 patients. All except one sample were positive for CD19-FCM analysis but negative for histologic examination and the conversion of CD19-FCM-positivity to CD19-FCM-negativity was associated with chemotherapy. These results suggest that CD19-FCM is useful for the evaluation of bone marrow involvement of B-cell lymphoma.
