Anti-cytokines belong to a new family of biological response modifiers which interfere with the biological functions of cytokines. An imbalance between cytokines and natural anti-cytokines may represent an important factor to explain the pathogenesis of some human diseases. Indeed, dysregulation of anti-cytokine serum levels was observed in cancers and auto-immune and infectious diseases. It was sometimes associated with disease activity and in some circumstances they may help to predict clinical response to treatment. Control of disease activity in septic shock and auto-immune diseases was demonstrated after administration of anti-cytokines such as soluble TNF receptors and IL1ra inhibitors. Therefore these agents are promising tools for diagnosis and immunotherapy.