Non-malignant T-cells lacking multiple pan-T markers can be found in lymph nodes

In order to observe and ascertain the properties of a sub-group of T cells in the lymph node (LN) from seven patients who did not suffer from T cell lymphoproliferative disorders (T-LPDs), the expression levels of several pan-T markers were evaluated by multiparameter flow cytometry (FC) and the clonality of these T-cells was evaluated by both FC analysis and PCR assessment. It turned out that multiple pan-T-cell markers such as CD2, CD5 and CD7 were found to be lost in these T cells. The majority of them were positive for TCRαβ, only a minority of them being positive for TCRγδ. A subset of these T-cells were positive for CD4 or CD8 or dual-negative for CD4 and CD8. Oligoclonality was detected in one case by FC, while clonal TCR rearrangement was detected in three cases. Absence of multiple pan-T-cell markers could be found in benign T cells in LNs.