Infrequent tacrolimus-induced nephrotoxicity in French patients with steroid-dependent nephrotic syndrome

Area of Science:

• Pediatric Nephrology
• Pharmacology
• Immunosuppression

Background:

• Calcineurin inhibitors (CNI) are crucial for treating severe idiopathic nephrotic syndrome (INS) in children.
• Chronic nephrotoxicity with irreversible lesions is a significant concern with CNI therapy.
• Identifying risk factors and monitoring for CNI-induced kidney damage is essential.

Purpose of the Study:

• To evaluate the incidence of chronic CNI-induced nephrotoxicity in children with steroid-dependent INS.
• To assess the utility of kidney biopsies in detecting CNI-induced lesions in this patient population.
• To inform treatment strategies and long-term management of pediatric INS.

Main Methods:

• Retrospective study of children with steroid-dependent INS on CNI for over one year.
• Inclusion of patients where CNI could not be substituted with mycophenolate mofetil.
• Analysis of kidney biopsy findings, clinical data, and treatment duration.

Main Results:

• Twenty-one children were included, with a median CNI treatment duration of 30 months.
• Minimal change disease was diagnosed in 20/21 patients; focal segmental glomerulosclerosis in 1/21.
• Chronic CNI-induced nephrotoxicity was infrequent, observed in only one patient (arteriolar hyalinosis and fibrosis).

Conclusions:

• CNI-induced chronic nephrotoxicity was uncommon in this cohort of children with INS.
• Kidney biopsies are valuable for excluding chronic CNI-induced lesions in patients requiring long-term or high-dose CNI therapy.
• This study supports careful monitoring and judicious use of CNIs in pediatric nephrotic syndrome.