Early Initiation of TNF Inhibitors for Tubulointerstitial Nephritis and Uveitis (TINU)

Tubulointerstitial nephritis and uveitis (TINU) syndrome is traditionally treated with corticosteroids followed by antimetabolites. The efficacy of early tumor necrosis factor-α (TNF) inhibitor therapy in TINU has not been sufficiently assessed. This case series describes the ocular and renal outcomes of treating TINU with TNF inhibitors (TNFi) and antimetabolites.

Retrospective data was collected on medication use and outcomes in nine pediatric TINU patients. Patients were split based on corticosteroid-sparing therapy: Group A only used antimetabolites and Group B used TNFi. Groups were assessed for corticosteroid sparing efficacy, renal and ocular quiescence, and medication adverse effects.

There were two Group A and seven Group B patients. Five Group B patients previously failed antimetabolite monotherapy. In Group A, median time from corticosteroid-sparing therapy initiation to prednisone cessation was 26.5 weeks, during which mean peak body mass index (BMI) increase was 1.65 kg/m². In Group B, median corticosteroid sparing time was 28 weeks and mean BMI increase was 4.16 kg/m². After removing time on antimetabolite monotherapy, median corticosteroid sparing time was 6 weeks and mean BMI increase was 2.03 kg/m². Five patients taking antimetabolites and one taking TNFi had uveitis relapses. No renal relapses were reported. Only mycophenolate mofetil was associated with symptomatic adverse effects.

TNFi controlled ocular and renal inflammation in TINU. Furthermore, some patients fail antimetabolite therapy and experience side effects of prolonged corticosteroid therapy. We recommend early and even first-line usage of TNFi as corticosteroid-sparing therapy with or without antimetabolites.