[Interstitial tubulo-nephritis and uveitis (Nitu syndrome). Apropos of a case]

Acute renal failure due to tubulo-interstitial nephritis developed in a 12 year old boy. It was accompanied by an inflammatory syndrome consisting of a markedly increased erythrocyte sedimentation rate and high levels of C. reactive protein and fibrin. The association of these anomalies with an uveitis are typical of the Tinu syndrome (tubulo-interstitial nephritis uveitis) first described by Dobrin and al. in 1975. The interest of this case lies in the observation of focal chorioretinitis, as yet never described. The possibility of toxoplasmosis is discussed; it could be a direct etiologic factor or could represent a concurrent phenomenon. However no evidence of toxoplasmic infection could be demonstrated in this case, nor in any case previously reported. Light microscopic examination of a renal biopsy reveals diffuse monocellular interstitial infiltration and epithelioid granulomas. In some cases, non-specific bone marrow and lymph node granulomas have been found. In the Tinu syndrome, the nephropathy is completely reversible, either spontaneously or following steroid treatment; this contrasts with the tendency towards relapse of the uveitis. The possible pathogenesis and the relationship with other idiopathic acute nephritis and uveitis are discussed. As in some previous publications, the presence of circulating immune complexes in our patient would suggest the involvement of the immune system. Temporary depression of cellular immunity was also observed in some cases. But the etiology and the pathogenesis of this syndrome are still unknown.