Idiopathic
tubulointerstitial nephritis and uveitis (
TINU) syndrome is an uncommon condition, characterized by
acute tubulointerstitial nephritis (
TIN) with a favorable course and
uveitis with a chronic relapsing course. The pathogenesis remains unclear, but a lymphocyte-mediated immune mechanism has been suggested. A 9-year-old boy was evaluated for
fatigue and 2 kg of
weight loss.
Renal glucosuria, elevated urine beta(2)-microglobulin (MG), progressive renal dysfunction, polyclonal
hypergammaglobulinemia, various
autoantibodies and abnormal lymphocyte phenotypes were found. A renal biopsy revealed acute
TIN. After 2 months of treatment with
prednisolone, renal function and polyclonal
hypergammaglobulinemia were normalized. While tapering
prednisolone,
anterior uveitis developed, which was improved with topical
steroid. But abnormal lymphocyte phenotypes and
autoantibodies persisted on low-dose
prednisolone.
Uveitis became aggravated, and urine beta(2)-MG increased again. The second renal biopsy (7 months later) was normal except for minimal focal interstitial
fibrosis.
Uveitis was not responsive to systemic
steroids, but improved with additional
cyclosporin. Abnormal lymphocyte phenotypes improved, and most
autoantibodies disappeared. We report a rare case of idiopathic
TINU syndrome with severe immunologic dysregulation, which correlated with the clinicopathological and biochemical parameters. The information about lymphocyte phenotypes and
autoantibodies may provide more insight into the pathophysiology and the
clinical course of
uveitis in this rare disorder.