Persistent non-neoplastic γδ-T cells in cerebrospinal fluid of a patient with hepatosplenic (γδ) T cell lymphoma: a case report with 6 years of flow cytometry follow-up

[摘要] Hepatosplenic (γδ) T-cell lymphoma (HSTCL) is an uncommon T-cell lymphoma with an aggressive clinical course and poor prognosis. Bone marrow and peripheral blood are frequently involved, with central nervous system involvement less common. We describe a case of a 31-year old man diagnosed with a γδ HSTCL in 2003, successfully treated with chemotherapy and allogeneic stem cell transplantation, and followed from 2003 to present. Four-color flow cytometry (FC) was performed on a BD FACSCalibur and data analyzed with CellQuest Pro and FCS Express software. For cerebrospinal fluid (CSF), all cells were acquired due to limited material. Cytological correlation was available on all specimens. Molecular studies for T-cell gene rearrangement were non-contributory. By FC, the diagnostic HSTCL immunophenotype was CD3 (+), CD7 (+), CD2 (+), CD5 (-), CD4 (-), CD8 (-), TCR γδ (+). Subsequent CSF FC analysis revealed a distinct population of γδ T-cells in all specimens, ranging from <1% to 13% of lymphocytes. Consistently, the γδ T-cells exhibited a different immunophenotypic profile from the reported diagnostic immunophenotype; they expressed CD5, and exhibited a heterogeneous pattern of CD8 expression. Comparison to in-house cases from patients with hairy cell leukemia and concomitant increases in non-neoplastic γδ T-cells was performed. The persistent γδ T-cells from the CSF of the patient with HSTCL were immunophenotypically consistent with non-neoplastic γδ T-cells. We describe an unusual case of persistent γδ T-cells in the CSF of a patient during 6 years of flow cytometric follow-up after treatment for γδ HSTCL. By cytology, non-neoplastic and malignant γδ T-cells are often difficult to distinguish. FC analysis helps to make this distinction, even with a limited panel. By FC, the γδ-T cells in the CSF of this patient are immunophenotypically consistent with non-neoplastic γδ T-cells. Remarkably, this finding is underscored by the patient's unusual clinical picture; he remains well and disease free.

[学科分类] 生理学与病理学

[关键词] Gamma-delta T cells;hepatosplenic T cell lymphoma;cerebrospinal fluid;flow cytometry;T-cell gene rearrangement