IL-19 increases the production of Th2 cytokines in T-lymphocytes and induces expression of IL-10 in monocytes.
Disorder of the IL-19 production probably has an affect to different allergic reactions and other Th1 type athopic and skis pathogeneses, eg. psoriasis.
IL-19 also forms homologs with IL-20 and IL-24 and thus is able to bind the interleukin-20 receptor complex and lead to the activation of the signal transducer and activator of transcription 3 (STAT3). STAT3 is necessary for embryonal development and Th17 differentiation . The IL-20 receptors are predominantly found in the mesenchymal region of tissues, lungs and reproduction organs.
A similar cytokine in mouse is reported to up-regulate the expression of IL6 and TNF-alpha and induce apoptosis, which suggests a role of this cytokine in inflammatory responses. Alternatively spliced transcript variants encoding the distinct isoforms have been described.
Interleukin-19 is a cytokine that belongs to the IL-10 family of cytokines along with several other interleukins including IL-10, IL-20, IL-22, IL-24, IL-26, and several virus-encoded cytokines. It signals through the same cell surface receptor (IL-20R) that is used by IL-20 and IL-24.
^Chang C, Magracheva E, Kozlov S, Fong S, Tobin G, Kotenko S, et al. (January 2003). "Crystal structure of interleukin-19 defines a new subfamily of helical cytokines". The Journal of Biological Chemistry. 278 (5): 3308–13. doi:10.1074/jbc.M208602200. PMID12403790.
^Witte E, Kokolakis G, Witte K, Philipp S, Doecke WD, Babel N, et al. (November 2014). "IL-19 is a component of the pathogenetic IL-23/IL-17 cascade in psoriasis". The Journal of Investigative Dermatology. 134 (11): 2757–2767. doi:10.1038/jid.2014.308. PMID25046339.