We examined the mRNA expression for a representative TH1 cytokine (e.g. interferon [IFN]-γ), a TH1 inducer (e.g. IL-12), a TH2 cytokine (IL-4) and iNOS, which catalyses the generation of NO from L-arginine and plays a major role in colitis. The gene discussed is NOS2; the disease is colitis.