RESUMO
Fibrillary glomerulonephritis (FGN) was previously defined by glomerular deposition of haphazardly oriented fibrils that stain with antisera to immunoglobulins but do not stain with Congo red. We report what is to our knowledge the first series of immunoglobulin-negative FGN, consisting of 9 adults (7 women and 2 men) with a mean age at diagnosis of 66 years. Patients presented with proteinuria (100%; mean protein excretion, 3g/d), hematuria (100%), and elevated serum creatinine level (100%). Comorbid conditions included carcinoma in 3 and hepatitis C virus infection in 2; no patient had hypocomplementemia or monoclonal gammopathy. Histologically, glomeruli were positive for DNAJB9, showed mostly mild mesangial hypercellularity and/or sclerosis, and were negative for immunoglobulins by immunofluorescence on frozen and paraffin tissue. Ultrastructurally, randomly oriented fibrils measuring 13 to 20nm in diameter were seen intermingling with mesangial matrix in all and infiltrating glomerular basement membranes in 5. On follow-up (mean duration, 21 months), 2 had disease remission, 4 had persistently elevated serum creatinine levels and proteinuria, and 3 required kidney replacement therapy. Thus, rare cases of FGN are not associated with glomerular immunoglobulin deposition, and the diagnosis of FGN in these cases can be confirmed by DNAJB9 immunostaining. Pathogenesis remains to be elucidated.
Assuntos
Glomerulonefrite/metabolismo , Proteínas de Choque Térmico HSP40/metabolismo , Imunoglobulina G/metabolismo , Proteínas de Membrana/metabolismo , Chaperonas Moleculares/metabolismo , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Creatinina/metabolismo , Feminino , Membrana Basal Glomerular/ultraestrutura , Mesângio Glomerular/ultraestrutura , Glomerulonefrite/epidemiologia , Glomerulonefrite/patologia , Glomerulonefrite/terapia , Hematúria/metabolismo , Humanos , Imunossupressores/uso terapêutico , Cirrose Hepática/epidemiologia , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Neoplasias/epidemiologia , Proteinúria/metabolismo , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Terapia de Substituição Renal , EscleroseRESUMO
Renal involvement often occurs in HCV infection. The most common renal manifestation is MPGN with or without cryoglobulinemia. Patients with glomerulonephritis may have no clinical evidence of systemic or liver involvement. Pathogenesis of HCV-associated MPGN is mediated by glomerular deposition of circulating immune complexes containing HCV and anti-HCV. The treatment of choice for MPGN is IFN-alpha. However, success is limited, and many patients fail to respond or experience relapse on discontinuation of therapy. Newer treatment modalities, such as high-dose IFN-alpha and recombinant IFN alpha-2b and ribavirin combination therapy, have led to improved suppression of HCV RNA levels.