A boy with IgA nephropathy complicated by tubulointerstitial nephritis and uveitis (TINU) syndrome

Abstract

Background: Abnormal cellular and humoral immunity underlie both immunoglobulin A (IgA) nephropathy and tubulointerstitial nephritis and uveitis (TINU) syndrome. We encountered a teenage boy who developed TINU syndrome during the course of IgA nephropathy.

Case report: 1 year after onset of IgA nephropathy following acute enteritis, a 14-year-old boy again experienced acute enteritis caused by Campylobacter jejuni, which was followed by TINU syndrome with prominent low-molecular-weight proteinuria. Renal histologic examination showed T-cell-dominant tubulointerstitial infiltration of marked immune cells including CD54-positive cells. Steroid therapy improved renal function, reversing aggravation of IgA nephropathy by TINU syndrome.

Conclusions: The boy's human leukocyte antigen profile suggested predisposition to these two diseases, triggered by which were intestinal infections. The enteritis probably induced abnormalities in cellular and humoral immunity. Low-molecular-weight proteinuria, which reflected our patient's tubulointerstitial lesions, should call for consideration of TINU syndrome, including ophthalmologic assessment for possible uveitis.