In vivo, only 3 injections of the anti-GITR antibody (once a week for 3 weeks) to very young BALB/c mice (2 week-old) induced by 3 months of age histological and serological evidence of autoimmune gastritis [1], a situation partly resembling that induced following elimination of CD4+CD25+ T cells by day 3 thymectomy in BALB/c mice [46]. The gene discussed is TNFRSF18; the disease is autoimmune gastritis.