ILF3 is a transcription factor required for T-cell expression of interleukin 2. It binds to a sequence in the IL2 enhancer known as the antigen receptor response element 2. In addition, ILF3 can bind RNA and is an essential component for encapsidation and protein priming of hepatitis B viral polymerase. ILF3 has been identified as autoantigens in mice with induced lupus, in canine systemic rheumatic autoimmune disease, and as a rare finding in humans with autoimmune disease.