Monocyte disorders associated with T cell defects in patients with solid tumors.

T cells proliferate in response to autologous monocytes in the autologous mixed lymphocyte reaction (AMLR). AMLR was found to be impaired in patients with advanced cancer (stages III and IV), whereas normal values were found in the early stages of the disease (stages I and II). Peripheral T lymphocytes from patients with advanced stages also exhibited a decreased ability to produce Interleukin-2 (IL-2) during an AMLR response, whereas production of IL-2 by T cells in stages I and II was comparable to that of normal donors. The impaired IL-2 production by T lymphocytes in the AMLR was associated with high concentrations of soluble interleukin-2 receptor (sIL-2R) in culture supernatants and reduced expression of membrane-bound interleukin-2 receptors (IL-2R) on the same AMLR-activated T lymphocytes. These abnormalities in T cells from cancer patients were demonstrated to be associated with dysfunctions of autologous monocytes. Thus monocytes from patients with advanced cancer exhibited diminished expression of HLA-DR antigens and produced low levels of Interleukin-1 beta (IL-1 beta) and Tumor Necrosis Factor a (TNFa). No changes were detected in the expression of HLA-A, -B, -C antigens. The results presented here demonstrate that decreased in vitro T cell responses may be attributed to monocyte dysfunctions in these patients and provide new information for a better understanding of the impaired T cell function in cancer patients.