CD5 Expression in Mature T Cell Lymphoma

• Published in: Blood 2023-11, Vol.142 (Supplement 1), p.6195-6195
• Main Authors: Cao, Miao, Tavakkoli, Montreh, Chong, Elise A., Carter, Jordan S, Ruella, Marco, Landsburg, Daniel J., Nasta, Sunita D., Svoboda, Jakub, Schuster, Stephen J, Barta, Stefan K.
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2023-188043

Background Mature T-cell lymphoma (TCL), an aggressive and heterogenous group of T cell neoplasms, constitutes less than 15% of adult non-Hodgkin lymphomas. CD5 is an inhibitory T cell receptor molecule expressed on mature T cells. CD5 expression has been associated with worse outcomes in B-cell malignancies, however this association has not been explored in TCL. Furthermore, CD5 has become a promising immunotherapeutic target for TCL. We herein aimed to characterize CD5 expression in TCL subtypes at diagnosis and relapse, and its association with clinical features and outcomes in a single center cohort. Methods We retrospectively identified 109 patients (pts) diagnosed with non-cutaneous and non-leukemic mature TCL, with data on CD5 expression on tumor tissue by immunohistochemistry (IHC) and/or flow cytometry (FC), from the electronic medical records at the Hospital of the University of Pennsylvania (HUP). CD5 positivity (CD5+) was defined as any percentage of CD5+ malignant cells on FC and/or IHC. Chi-square test was used to compare baseline pt characteristics at the initial presentation between CD5 expression groups. Treatment response (TR) was defined as achieving complete or partial response by the end of initial treatment. Logistic regression models were used to assess the impact of clinical parameters on the overall TR rate and odds ratios (OR) were computed. Cox proportional hazards models were used to evaluate the effects of clinical parameters on overall survival (OS) and progression-free survival (PFS) and were reported as hazard ratios (HR). We also conducted Kaplan-Meier (KM) analyses for OS and PFS by CD5 expression status. The OR and HR are reported with 95% CI in brackets. P-values 60 (CD5-:34.7%, CD5+:55.0%, p=0.0343), and stage 3 or 4 (CD5-:46.9%, CD5+:70%, p=0.0142), but fewer CD5+ pts had EN involvement at diagnosis (CD5-:77.6%, CD5+:50%, p=0.0031). CD5 was also differentially expressed by TCL subtypes: nearly all TFH