Long-term clinical characteristics and renal prognosis of children with tubulointerstitial nephritis and uveitis syndrome.

BACKGROUND: Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare disease, especially in children. Owing to the short-term observational period and the small number of patients analyzed in previous reports, the long-term clinical and laboratory characteristics and renal prognosis of children with TINU syndrome remain unclear. METHODS: In this retrospective observational study, we enrolled 29 children with TINU syndrome from February 1990 to February 2019. RESULTS: During the median follow-up duration of 38 months, the kidney function, urinary ß2 microglobulin-creatinine ratio (U-ß2MG/Cr), and uveitis in the patients had significantly improved at 24, 6, and 36 months after diagnosis. Higher U-ß2MG/Cr was associated with longer duration of kidney function normalization. Half of the patients required uveitis treatment for 5 years after the diagnosis. CONCLUSIONS: Patients with severe low-molecular weight proteinuria at diagnosis needed a longer duration to achieve improvements in kidney function. Uveitis has a much longer treatment period than tubulointerstitial nephritis. This study demonstrates the good prognosis of children with TINU syndrome in terms of their long-term clinical and laboratory characteristics.