Interleukin-2 mediated regulation of mitogen-activated T cell reactivity from different lymphoid sources in patients with squamous cell carcinoma of the oral cavity

Peripheral blood lymphocytes (PBL) from patients with oral cancer (treated and untreated), oral leukoplakia and healthy donors; lymphocytes from metastatic and non-metastatic lymph nodes (met LNL and non-met LNL); and tumor infiltrating lymphocytes (TIL) were tested for proliferative response to mitogen PHA (phytohemagglutinin) and its augmentation by recombinant Interleukin-2 (rIL-2), for expression of Tac antigen (CD25) and for production of IL-2. Depressed PHA responses were found in PBL of treated and untreated patients, and in TIL. Addition of IL-2 could bring about 16% to 31% augmentation in lymphocyte response to PHA from all the three sources. PBL from 50% of healthy donors, 45% of patients with leukoplakia, 25% untreated oral cancer patients and 35% treated oral cancer patients showed IL-2 mediated augmentation of PHA response. While, 40% non-met LNL samples, 70% met LNL samples and only 23% TIL samples showed increased mitogen induced proliferation by IL-2. The augmented levels of PHA response of PBL from treated and untreated patients, and of TIL, were still below those of normal PBL. PBL from patients with leukoplakia, treated oral cancer patients and TIL showed depressed CD25 antigen expression. Depressed IL-2 production was observed only in PBL of leukoplakia patients. Thus the IL-2 mediated events of T cell activation from different lymphoid sources in patients with oral cancer did not correlate with their proliferative responses.