Hepatitis B

Hepatitis B virus (HBV) has been causally linked to a variety of renal diseases, the most common being glomerular diseases and systemic autoimmune disease. Membranous nephropathy (MN) is the commonest HBV-associated glomerulonephritis (HBV-GN), followed by membranoproliferative glomerulonephritis (MPGN), mesangial proliferative glomerulonephritis, immunoglobulin (Ig)-A nephropathy, and focal segmental glomerulosclerosis (FSGS). Polyarteritis nodosa is a rare manifestation. The incidence of HBV-associated renal diseases seems to be decreasing with the introduction of vaccination programmes.HBV-MN is the most frequent cause of nephrotic syndrome in children in countries with high endemicity of HBV infection. The clinical course is usually benign in children with high rates of spontaneous remission rates and low risk of progression to renal failure. The prognosis is worse in adults. Of the systemic autoimmune disorders associated with HBV infection that involve the kidneys, the strongest link has been found with polyarteritis nodosa (PAN), a lesion that causes arteritis of medium-sized renal vessels. HBV-associated PAN (HBV-PAN) usually manifests in the first year after infection, and is clinically indistinguishable from classic PAN.Diagnosis of HBV-GN or -PAN is based on the clinical picture, histological findings, evidence of viral replication in serum and/or liver and detection of HBV antigens or DNA in the tissue. Besides deposition of immune complexes, other mechanisms such as virus-induced cytopathic damage have been proposed to explain the pathogenesis.HBV-GN and HBV-PAN appear to respond to antiviral treatment. Both show remission after HBeAg seroconversion. The available studies predominantly employed first-generation agents like interferon alpha and lamivudine, which showed suppression of viral replication and clinical remission of HBV-associated renal disease. Immunosuppressive therapy appears to be inevitable for the control of severe HBV-PAN and could be helpful in addition to antiviral treatment for cases of HBV-GN not responding clinically to antiviral treatment.