The grouped vertical bar graph represents the frequency of the 3 most common causes of ISx according to post-KT periods evenly divided in to three sections. Black bars represent GI problem-induced ISx change, gray bars represent infection-induced ISx change, and white bars represent ISx change due to bone marrow suppression. All of three causes of ISx change were common in the first tertile period. The GI problem was the most common in the first tertile period, while infection became the main cause of the ISx change in the second and third tertile periods. Abbreviation: KT, kidney transplantation; GI, gastrointestinal; ISx, immunosuppressant.