Cytokines are soluble glycoproteins released by cells of the immune system , which act nonenzymatically through specific receptors to regulate immune responses. Cytokines resemble hormones in that they act at low concentrations bound with high affinity to a specific receptor .

Common cytokines in allergology include:

• Interleukins
• Lymphokine
• Interferon
• Colony Stimulating Factor
• Platelet-Activating Factor
• Tumor Necrosis Factor