Role of renal preS1/S2-Ag and other HBV antigen determination in diagnosis of HBV-associated glomerulonephritis

AIM：To detect the expression of preS1/S2 antigen (preS1/S2-Ag) and other antigens of hepatitis B virus (HBV) in renal tissues of patients with HBV-associated glomerulonephritis (HBV-GN), and to analyze their roles in the diagnosis of HBV-GN.
METHODS：Patients hospitalized in our department from January in 2003 to January in 2013 were retrospectively studied. A total of 49 patients with positive HBV surface antigen (HBsAg) serology, clinical manifestations of hematuria and/or proteinuria, and pathological diagnosis of glomerulonephritis, without systemic lupus erythematosus, anaphylactic purpura, diabetes or hepatitis C, were selected. PreS1/S2-Ag, HBV e antigen (HBeAg), HBsAg and HBV core antigen (HBcAg) in the renal tissues were examined. Five cases of glomerular minimal-change disease (MCD) with negative HBsAg and 5 cases of non-glomerulonephritis with positive HBsAg served as controls. RESULTS：The positive rates of preS1/S2-Ag, HBeAg, HBsAg and HBcAg in the renal tissues from the 49 patients of glomerulonephritis with HBV infection were 32.7% (16 cases), 38.8% (19 cases), 14.3% (7 cases) and 46.9% (23 cases), respectively. Total antigen positive rate was 70.2% (36 cases). The expression of preS1/S2-Ag was located in the cytoplasm of renal tubular epithelial cells, glomerular epithelial cells, endothelial cells and mesangial cells, and positively correlated with the expression of HBcAg (r=0.459, P<001). The 4 antigens were not detected in the 5 cases of HBsAg-negative patients with glomerular MCD. In the 5 cases of HBsAg-positive patients with non-glomerulonephritis, there were 2 cases expressing HBeAg and 1 case expressing HBcAg, but no cases expressing preS1/S2-Ag or HBsAg. CONCLUSION：The expression of preS1/S2-Ag in renal tissues suggests that HBV may invade the cells of renal tissue. Combined detection of the 4 antigens could elevate the rate of diagnosis of HBV-GN.