M: male; F: female; CD: Crohn's disease; UC: ulcerative colitis; NM: not mentioned; SSZ: sulfasalazine; IBD: inflammatory bowel disease; ANB: antinuclear antibody; RMSF: Rocky Mountain spotted fever; CRP: C-reactive protein; mPNL: methylprednisolone; RF: rheumatoid factor; GC: glucocorticoids; LMWHs: low-molecular-weight heparin; GCS-F: granulocyte colony-stimulating factor; HLH: hemophagocytic lymphohistiocytosis; LAD: lymphadenopathy; PRED: prednisone; PT: prothrombin time; LDH: lactate dehydrogenase; SIHS: sulfasalazine-induced hypersensitivity syndrome. The gene discussed is F2; the disease is Crohn disease.