Abstract

There are many complex relationships between tu- mour cells and effector cells in the immune system. These interactions are controlled predominantly by cy- tokines, either within the tumour environment, or sys- temically where the effector cells may be stimulated as a response to the presence of the tumour. Favourable clinical responses in cancer patients have been shown to be associated with enhanced cell-mediated immunity as well as T cell infiltration in tumours. This status is controlled in part by a predominantly Th1 cytokine profile e.g. IFN γ , TNF α and IL-12. Conversely, pa- tients with advancing cancer may have impaired cell- mediated immunity as a result of an imbalance of Th1 and Th2 cytokines e.g. IL-4 and IL-10 [6,9,15]. Whilst cytokines have long been known to orchestrate the im- mune system by allowing communication between reg- ulatory and effector cells, the pleiotropic nature of these molecules results in a very complex environment in which to study any single molecule’s properties. Several in vitro protocols have been developed,which aim to closely reflect cytokine production and T cell function in vivo. However, these assays have been developed in artificial settings and as such only allow conclusions to be drawn within a defined context [11]. The aim of this report is to outline the basic proto-cols and applications for the detection of intracellular cytokines by flow cytometry, in the context of disease monitoring.