The serum levels of IL-12 and IL-16 in cancer patients. Relation to the tumour stage and previous therapy.

In this study the serum levels of the cytokines IL-12 (p40 and p70) and IL-16, and the number of cells which produce them (monocytes, CD8+ T cells, B cells), were measured in 76 cancer patients with different types of cancer (breast > gastrointestinal > uterine/ovarian > renal/bladder) and compared with 28 healthy controls. The patients were divided into four groups: stage I+II without or after chemo/radiotherapy, and stage III+IV without or after chemo/radiotherapy. The distribution of patients in the groups was similar. The levels of cytokines were determined by ELISA, the number of the immunocompetent cells by flow cytometry. The serum values of IL-12 were significantly elevated in each tumour stage both without and after additional chemo/radiotherapy. They correlated positively with the progression (P < 0.02). The serum values of IL-16 were only significantly increased in tumour stage III+IV without or after chemo/radiotherapy. The number of monocytes showed no alteration in any investigated group, chemo/radiotherapy significantly reduced the number of CD8+ T cells at each stage, and the number of B cells was negatively correlated with the disease progression (P < 0.03). The results indicate that there is an increase of IL-12 and IL-16 in sera during tumour progression due only to an alteration in the function of the immunocompetent cells, not to an increased number. This investigation reports for the first time that IL-16 is involved in cancer diseases.