Interleukin1receptor,typeI(IL1R1),alsoknownasCD121a(ClusterofDifferentiation121a),isaninterleukinreceptor.Theproteinencodedbythisgeneisacytokinereceptorthatbelongstotheinterleukin-1receptorfamily.IL1R1alongwithinterleukin1receptor,typeII(IL1R2),interleukin1receptor-like2(IL1RL2),andinterleukin1receptor-like1(IL1RL1)formacytokinereceptorgeneclusterinaregionmappedtochromosome2q12.Thisproteinisareceptorforinterleukin1alpha(IL1A),interleukin1beta(IL1B),andinterleukin1receptorantagonist(IL1RA).Itisanimportantmediatorinvolvedinmanycytokineinducedimmuneandinflammatoryresponses.