Effects of isolated limb perfusion with tumour necrosis factor-alpha on the function of monocytes and T lymphocytes in patients with cancer

The objective of the present study was to investigate the effects of isolated limb perfusion (ILP) with tumour necrosis factor alpha (TNF-alpha) and melphalan in patients with cancer on, first, plasma levels of cytokines, second, systemic monocyte and T-lymphocyte distribution and, third, the ability of mononuclear cells to produce cytokines upon stimulation in vitro. Six patients undergoing an ILP were entered into the study (group 1). In addition, patients undergoing a major surgical operation (group 2) minor operation (group 3) as well as healthy volunteers (group 4) were included as control groups. Sensitive enzyme-linked immunosorbent assays (ELISAs) were used to measure TNF-alpha and interleukin-6 (IL-6) plasma levels at various time points during and after operation. Furthermore, the percentage of monocytes and T lymphocytes was determined in all studied groups using a FACScan. In addition, cytokine production upon stimulation with lipopolysaccharide (LPS) and a combination of anti-CD3/anti-CD28 monoclonal antibodies in whole-blood cultures was investigated. Increased plasma levels of TNF-alpha and IL-6 in patients undergoing ILP was observed, but only IL-6 appeared to be increased in patients treated with a major operation. No significant fluctuations were found in the other groups studied. Concerning the number of monocytes, a significant decrease was observed only in patients treated with ILP. Furthermore, a decreased production of TNF-alpha, IL-6 and IL-8 upon various types of stimulation in vitro was found in those patients, but also after a major operation. In conclusion, the results of the present study show increased plasma levels of cytokines in patients treated with ILP and major operation. Furthermore, a decrease in numbers of monocytes in the circulation and the ability of mononuclear cells to produce cytokines in vitro may be induced by administration of TNF-alpha in ILP. Although similar results were found in patients treated with major operation, the underlying mechanisms of this phenomenon remain to be elucidated.