Novel CD19 expression in a peripheral T cell lymphoma: A flow cytometry case report with morphologic correlation
Kathryn Rizzo1, Maryalice Stetler-Stevenson, Wyndham Wilson
1Flow Cytometry Unit, Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
Cytometry. Part B, Clinical Cytometry
|August 2, 2008
Summary
This study reports the first case of peripheral T-cell lymphoma with aberrant CD19 coexpression. This finding expands the understanding of T-cell lymphoma immunophenotypes.
Area of Science:
- Hematology
- Oncology
- Immunology
Background:
- Peripheral T-cell lymphomas (PTCLs) are rare lymphoid malignancies.
- PTCLs typically exhibit T-cell antigen loss and clonal T-cell receptor (TCR) gene rearrangement.
- Aberrant CD20 expression has been noted in rare PTCL cases, but CD19 coexpression is unprecedented.
Observation:
- A lymph node specimen showed a diffuse atypical lymphoid proliferation.
- Immunohistochemistry confirmed T-cell markers (CD3, CD2, CD43) and negative B-cell markers.
- Flow cytometry identified an aberrant T-cell population with unusual marker expression, including bright CD19.
Findings:
- A clonal TCR gene rearrangement confirmed neoplastic T-cells.
- The aberrant T-cell population expressed CD2, CD3, CD27, TCR alpha/beta, CD52, CD38, CD45, and CD26.
- Crucially, this T-cell population aberrantly coexpressed CD19.
Implications:
- This case represents the first documented instance of peripheral T-cell lymphoma with CD19 coexpression.
- This finding challenges current diagnostic paradigms for T-cell lymphomas.
- Further research is needed to understand the clinical significance and potential therapeutic targets for CD19-expressing T-cell lymphomas.
