The prognostic significance of lymphopenia in peripheral T-cell and natural killer/T-cell lymphomas: A study of 826 cases from the International Peripheral T-cell Lymphoma Project

Lymphopenia is a marker of inferior survival in patients with various malignancies. However, the prognostic significance of lymphopenia in peripheral T-cell lymphoma (PTCL) is unclear. We analyzed the prognostic significance of lymphopenia in 826 patients with different types of PTCL and natural killer/T-cell lymphoma (NKTCL) from the International Peripheral T-cell Lymphoma Project. Lymphopenia was defined as an absolute lymphocyte count of less than 1,000 cells per microliter. The overall frequency of lymphopenia was 35.3%, ranging from 21.1% in ALK⁺ anaplastic large cell lymphoma (ALCL) to 47.5% in angioimmunoblastic T-cell lymphoma (AITL). Lymphopenia was independently associated with an inferior overall survival (OS) in patients with the lymphoma type of adult T-cell leukemia/lymphoma (ATLL), with a 2-year OS of 15% versus 40% for those without lymphopenia (P < 0.001). Lymphopenia was also an adverse predictor of survival in PTCL, not otherwise specified, but was associated with other unfavorable prognostic factors. A trend toward inferior survival for lymphopenic patients was also observed in AITL, ALK^- ALCL and extranasal NKTCL lymphoma, whereas no difference in survival was found in nasal NKTCL, ALK⁺ ALCL, or enteropathy-associated T-cell lymphoma. In this study, lymphopenia was identified as a new adverse prognostic factor in the lymphoma type of ATLL.