Cytokines may exert anti-inflammatory properties, allowing the hypothesis of their potential therapeutic use. Targeting the cytokines balance may modify the course of subsequent inflammatory events in an autoimmune disease. Many data are available. Interferon-gamma can be blocked by an anti-interferon-gamma monoclonal antibody: if the treatment is administered in the early phase of an autoimmune disease such as collagen-induced arthritis, the course of the disease is worsened; if the treatment is given later, the disease can be improved; these results are mirrored by treatment with high doses of the cytokine itself. Pharmacologic effects of antiinflammatory cytokines such as interleukin (IL)-4, IL-10 or IL-13 are a protection against several experimental autoimmune diseases. The very short half-life of cytokines makes them difficult and expensive to use directly; in such occurrence, high quantities have to be frequently injected. In this context, gene therapy appears as an effective alternative solution: the transfection of cells with cytokines genes (e.g. either IL-4 or IL-13) then the engraftment of these vectors in animals, permit the in vivo secretion of high levels of cytokines, and result in the protection of the animals from the development of the disease.