Proliferative glomerulonephritis with monoclonal immunoglobulin light chain deposits: a rare entity mimicking immune-complex glomerulonephritis.

A 39-year-old man developed proteinuria, hematuria, and renal insufficiency. A renal biopsy revealed the presence of mesangial proliferative glomerulonephritis with monoclonal λ-light chain deposits without evidence of immunoglobulin G (IgG), immunoglobulin A (IgA) or immunoglobulin M (IgM) deposits. Electron microscopy revealed granular electron-dense deposits resembling immune-complex deposits. No monoclonal proteins were detected in the serum or urine. The patient was treated with an angiotensin II receptor antagonist, and his condition was almost stable during the 1-year follow-up. This case shares common pathological characteristics with the newly described entity referred to as "proliferative glomerulonephritis with monoclonal IgG deposits" in which, glomerular deposits are composed entirely of monoclonal IgG. Therefore, we term the unusual form of glomerulonephritis observed in the present case "proliferative glomerulonephritis with monoclonal immunoglobulin light chain deposits."

Tubulointerstitial nephritis and renal tubular acidosis of different types are rare but important complications of primary biliary cirrhosis.

BACKGROUND: A very few cases of biopsy-proven tubulointerstitial nephritis (TIN) in patients with primary biliary cirrhosis (PBC) have been reported. Although the clinical importance of this association has been suggested, information on its clinicopathological features and prognosis is limited. METHODS: We reviewed 5955 renal biopsies processed at our department, and identified four patients with TIN associated with asymptomatic PBC. We evaluated clinicopathological features and outcomes in these patients, and reviewed the previously reported cases of TIN associated with PBC. RESULTS: Our four patients were female. The patients' age at the time of renal biopsy ranged from 36 to 77. Three patients had been treated with ursodeoxycholic acid. All patients had urinary abnormalities such as proteinuria and elevated levels of urinary ß(2)-microglobulin, and three patients had renal insufficiency. All patients had distal renal tubular acidosis (RTA), and two patients also had Fanconi syndrome. Renal biopsy showed severe lymphocyte infiltration in the tubules and interstitium with mild-to-moderate tubular atrophy and fibrosis. All patients responded well to steroid therapy. On review of the previously reported five cases, all patients were female. The patients' age ranged from 42 to 68. Apparent symptoms linked to PBC were not described. All patients had renal insufficiency. Three patients suffering from bone pains or bone fractures also had Fanconi syndrome. Marked or transient improvements were observed after steroid therapy in three patients. CONCLUSIONS: TIN and RTA of different types are extremely rare but one of the important extrahepatic complications of PBC. Steroid therapy can be beneficial in treating PBC patients with these renal complications.

Angioimmunoblastic T-cell lymphoma and membranous nephropathy: a still unreported association.

A 21-year-old man with lymphadenopathy and Coombs-positive hemolytic anemia had been treated with steroid maintenance therapy. He developed nephrotic syndrome with size increase of lymphadenopathy. Lymph node examination disclosed angioimmunoblastic T-cell lymphoma (AITL). Light microscopy of a renal biopsy specimen showed typical features of membranous nephropathy (MN), such as bubbling appearance and spike formation. Immunofluorescence studies revealed no significant deposition of immunoglobulins. Electron microscopy showed sparse degenerative materials on the epithelial side of the glomerular basement membranes, with intervening spikes. These unique histological findings suggested secondary MN. High-dose steroid therapy followed by six courses of cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) therapy improved his symptoms. One-year follow-up revealed the patient in good health without any signs of relapse. Glomerular manifestations have rarely been reported in association with AITL. To our knowledge, this is the first reported case of nephrotic syndrome due to MN associated with AITL.

Steroid-responsive nephrotic syndrome in a patient with proliferative glomerulonephritis with monoclonal IgG deposits with pure mesangial proliferative features.

A 78-year-old woman developed acute-onset nephrotic syndrome. A renal biopsy showed mild mesangial proliferative glomerulonephritis. Immunofluorescence studies revealed granular IgG3- λ deposits within the mesangial area and along the glomerular capillary walls. Electron microscopy showed mesangial and subendothelial granular electron-dense deposits. The pattern of deposition was predominantly mesangial. Serum or urine monoclonal proteins were not detected. Middle-dose steroid therapy induced a rapid remission of nephrotic syndrome. We consider that this is the first case of steroid-responsive nephrotic syndrome due to an extremely rare glomerular disease, proliferative glomerulonephritis with monoclonal IgG deposits associated with pure mesangial proliferative features.

Reversible infliximab-related lymphoproliferative disorder associated with Epstein-Barr virus in a patient with rheumatoid arthritis.

A 63-year-old woman with active rheumatoid arthritis (RA) had been treated with methotrexate and prednisolone. She developed cervical lymph node swelling 30 months after the initiation of infliximab therapy. A computed tomography revealed cervical and mediastinal lymph node swelling and multiple nodules (up to 13 mm in diameter) in the lungs. A lymph node biopsy showed infiltration of numerous Hodgkin-like and Reed-Sternberg-like cells. Immunohistological studies showed that these cells were positive for CD15, CD30, and Epstein-Barr virus (EBV) latent membrane protein. In site hybridization revealed the presence of EBV RNA in the nuclei of these cells. EBV DNA was detected in the biopsy specimen by southern blot analysis. She was diagnosed as having EBV-associated lymphoproliferative disorder (LPD). Immunodeficiency-associated LPD related with infliximab therapy was considered. Cessation of infliximab therapy only led to dramatic regression of LPD. This case illustrates that EBV-associated LPDs can occur as part of infliximab adverse effects in patients with RA.