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 β2 microglobulin-creatinine ratio (U-β2MG/Cr), and uveitis in the patients had significantly improved at 24, 6, and 36 months after diagnosis. Higher U-β2MG/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. Graphical abstract