Immuno-inflammatory Aspects of Interleukin-21 in Periodontal Sequelae: Current Development

Interleukin-21 (IL-21) has a dual anti-inflammatory and pro-inflammatory role in chronic inflammation.
It causes breakdown of other surrounding hard and soft tissues by coupling with other destructive
mediators, along with increasing several other proinflammatory cytokines. This chapter describes
concepts in relation to effects of IL-21 on critical immune cells of both innate and adaptive immune
systems, and how the cytokine evades its deactivation through a positive feedback loop. The chapter
also reports results of an original study regarding quantification of IL-21 among types of periodontitis
and comparing its levels to healthy subjects. Previous literature and our current study results suggest
that IL-21 has a definite role in chronic and acute kind of inflammatory progression. Although, further
longitudinal studies will strengthen its evidence to be characterized as a true diagnostic periodontal
marker.