In this case, a 50-years-old woman with LN developed proteinuria, in spite of an administration of tacrolimus. The urinary level of proteinuria had not been reduced, then ARB was added, but the reduction of the urinary level of proteinuria was partially.
    ARB, therefore, was switched to ACE-I, then proteinuria was improved to a normal level. Both ACE-I and ARB show the protective effects for a renal function. These effects are observed in the chronic phase of lupus nephritis. The difference of the effect between ACE-I and ARB is not so much clear, and it has been postulated that the major pharmacological mechanism to the reducing proteinuria is the suppression of AngII activity in both drugs. Recently, it is suggested that the proper effect of ACE-I might have a great part of protection for renal function. This case suggests that ACE-I can be effective to the patients with LN who resists to ARB with different pharmacological activity.