Large tumour cell group, combinations of CMYC+ or PD-1+ tumour cells and intense PD-L1+ cell reaction are important prognostic factors in nodal T-cell lymphomas with T follicular helper markers

Abstract

Background The clinicopathological characteristics and prognostic factors in nodal T-cell lymphomas with T follicular helper markers (TFH+) are not adequately investigated. Methods Immunohistologically, we selected 22 patients with TFH + lymphoma in 47 of peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS), and subclassified into large and small cell groups. We compared the two groups with 39 angioimmunoblastic T-cell lymphoma (AITL) and seven follicular T-cell lymphoma (F-TCL) patients. Prognostic factors were analysed by overall survival in patients with three types of TFH + lymphomas. Results Thirteen large cell and nine small cell PTCL patients had more than two TFH markers including programmed cell death-1 (PD-1). Large cell TFH + PTCL showed CMYC expression in 10 patients (76.9%), and four of 11 large cell group (36.4%) had somatic RHOA G17V gene mutation by Sanger sequencing. In TFH + lymphomas, large cell TFH + PTCL patients showed significantly worse prognosis than those of the small cell group, AITL, and F-TCL (p < 0.05). CMYC + tumour cells, and combined PD-1 ligand 1 (PD-L1) + tumour cells and intense reaction of PD-L1 + non-neoplastic cells (high PD-L1 + cell group) were significantly poor prognostic factors (p < 0.05). Combinations of CMYC + or PD-1 + tumour cells and high PD-L1 + cell group indicated significantly poor prognosis (p < 0.01). Conclusion Large cell TFH + PTCL indicated poor prognosis in TFH + lymphomas. These data suggested that CMYC + tumour cells and intense PD-L1 + cell reaction influenced tumour cell progression in TFH + lymphomas, and PD-1 + tumour cell/intense PD-L1 + cell reactions may play a role in immune evasion.