Among the cytokines playing a role in asthma, IL-1 and TNF alpha or beta are important agents to be considered. IL-1 TNF alpha are produced by antigen-presenting cells. TNF alpha and beta are released by activated lymphocytes. Recently a natural inhibitor of IL-1 produced by monocytes or macrophages in the form of a 22-25 kD protein, which binds competitively to IL-1 receptors has been cloned and sequenced. This inhibitor is called the IL-1 receptors antagonist. Two types of TNF soluble receptors (55 and 75 kD) can be liberated from the surface of macrophages and neutrophils. These soluble receptors block both TNF alpha and beta activity. The respective roles of these cytokine inhibitors in the physiopathology of asthma need to be further defined, but new therapeutic perspectives are opening.