Are interleukins a cytokine?

Interleukins are a subfamily of cytokines. Although both are types of signaling molecules and both act as modulators of cellular behavior, there are a few significant points of distinction between the two: 

• Cytokines are a large group of cellular messenger molecules while interleukins are a subset of cytokines. 
• Cytokines refer to an umbrella group of small proteins involved in cell signaling, whereas interleukins refer to a specific group of cytokines that regulate the immune and inflammatory responses.
• Cytokines can have autocrine, endocrine or paracrine action, while interleukins have either autocrine or paracrine action.