Tubulointerstitial nephritis in a patient with probable autoimmune lymphoproliferative syndrome.

Autoimmune lymphoproliferative syndrome (ALPS) is caused by a nonmalignant defective Fas-mediated apoptosis. The main clinical manifestations are chronic lymphadenopathy, splenomegaly, and autoimmune cytopenia. Most patients with ALPS have a FAS germline mutation. ALPS has occasionally been associated with glomerulonephritis and we present the first report of tubulointerstitial nephritis associated with probable ALPS. A 5-year-old girl presented with fever, vomiting, hypertension, and azotemia. No autoantibodies, viral, or streptococcal antibodies were detected. A renal biopsy showed small-vessel vasculitis with normal glomeruli and inflammation in the interstitium. The patient responded to prednisolone treatment and obtained a full renal recovery. Symptoms of connective tissue disorder supervened and after the development of more pronounced splenomegaly, a diagnosis of ALPS was confirmed.