Hideaki Yamabe, MD, Second Department of Internal Medicine, Hirosaki University School of Medicine, 5 Zaifucho, Hirosaki 036 (Japan) References Johnson RJ, Gretch DR, Yamabe H, et al: Membranoproliferative glomerulonephritis associated with hepatitis C virus infection. N Engl JMed 1993;28:465-470. Yamabe H, Johnson RJ, Gretch DR, et al: Hepatitis C virus infection and membranoproliferative glomerulonephritis in Japan. J Am SocNephrol 1995;6:220-223. Doutrelepont JM, Adler M, Willems M, et al: Hepatitis C infection and membranoproliferative glomerulonephritis. Lancet 1993;341:317. Misiani R, Vicari O, Bellavita P, et al: Hepatitis C virus in renal tissue of patients with glomerulonephritis. Nephron 1994;68:400. Dear Sir, Membranoproliferative glomerulonephritis (MPGN) associated with hepatits C virus (HCV) infection has been recently reported [1] and its prevalence may be very high in primary MPGN [2]. This disease is clinically characterized by nephrotic syndrome, active HCV infection, frequent existence of cryoglobulinemia and hypocomple-mentemia and its pathogenesis is assumed to be caused by immune complex including HCV [1,2]. However, the glomerular deposition of HCV has not yet been demonstrated because the amount of HCV may be very small. We tried to detect the glomerular HCV deposition in this disease. Freezed kidney specimens obtained by renal biopsy in 6 patients were examined for glomerular HCV detection. Polyclonal rabbit antibody to HCV core antigen, which was provided by Dr. K. Shimotohno (National Cancer Center, Tokyo, Japan), was used as first antibody in the indirect immunofluorescence techniques. FITC-conjugated goat anti-rabbit IgG (Organon Teknika Co., Durham, N.C., USA) was used as second antibody. Negative control consisted of staining with normal rabbit serum or antibody to HCV absorbed with HCV core antigen, followed by FITCconjugated goat anti-rabbit IgG. Glomerular HCV deposition was observed in 2 of 6 patients with granular manner along the capillary wall and in the mesangium (fig. 1). Doutrelepont et al.