C3 and Crohn disease: CRP: 101 mg/L  ESR: 35 mm/hr  Platelets: 964 × 109/L  Colonoscopy: ileocecal valve thickened and distorted. Ileum shows active ulceration, cobble stone appearance, pseudo-polyp. Alteration of vascular pattern in cecum and ascending colon. Few active ulcers in hepatic flexure, transverse colon, recto sigmoid junction with pseudo-polyps  Impression: Crohn's disease or tuberculous colitis  Gut biopsy: Crohn's disease  ANA, ANCA: negative  C3/C4: 182/23  IgG: 869  NBT, CD3: Normal