Interleukin-27 receptor subunit alpha ( IL27RA) is also known as Cytokine receptor WSX-1, Cytokine receptor-like 1, Type I T-cell cytokine receptor (TCCR), ZcytoR1, IL27RA belongs to the type I cytokine receptor family and type 2 subfamily. IL27RA contains three fibronectin type-III domains. IL27RA is highly expressed in lymphoid tissues such as spleen, lymph nodes and peripheral blood leukocytes. IL27RA is receptor for IL27, but requires IL6ST/gp130 to mediate signal transduction in response to IL27. IL27RA involved in the regulation of Th1-type immune responses. IL27RA also appears to be involved in innate defense mechanisms.