Transition from endocapillary proliferative glomerulonephritis to membranoproliferative glomerulonephritis in a patient with a prolonged human parvovirus B19 infection

We report a case in which renal biopsies were performed 4 years apart in a woman with a prolonged human parvovirus B19 (HPB19) infection. When she was 29 years old the first biopsy, performed because of microscopic hematuria and mild proteinuria, showed endocapillary and mesangial proliferative glomerulonephritis in light microscopy as well as deposits of immunoglobulins (Igs) and complement C3 on capillary walls. Mesangial, intramembranous, and subepithelial hump-like electron dense deposits were seen in electron microscopy. The principal differential diagnoses, acute post-streptococcal glomerulonephritis and lupus nephritis, were unlikely, and her serological positivity for IgM antibody for HPB19 made us diagnose acute glomerulonephritis associated with HPB19 infection. The second biopsy, performed 4 years later because of persistent proteinuria and prolonged positivity for IgM antibody for HPB19, showed membrano-proliferative glomerulonephritis (MPGN) with mesangial interposition and with thickening and double contours of glomerular basement membrane. In tissues obtained in both biopsies, HPB19 DNA was detected by polymerase chain reaction. HPB19 infection has been widely known to cause various glomerular diseases. This case reveals that acute endocapillary proliferative glomerulonephritis can change into MPGN during prolonged HPB19 infection.