Treatment with GM-CSF and IL-2 in patients with metastatic colorectal carcinoma induced high serum levels of neopterin and sIL-2R, an indicator of immune suppression.

Cytokines may enhance the effect of therapeutic monoclonal antibodies (mAb). Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2) have been shown to increase ADCC levels. GM-CSF may augment the induction of an idiotypic network response (anti-tumour immunity).