TYPE-I MEMBRANOPROLIFERATIVE GLOMERULONEPHRITIS AND HCV INFECTION

Type I membrano-proliferative glomerulonephritis (MPGN) is secondary t o chronic bacterial, parasitic, viral (HB) infections, to autoimmune d isorders or primary or malignant haemopathies. MPGN are thought to be linked to the deposition of immune complexes preformed in the circulat ion or formed in situ in the glomeruli. A link between HCV and type I MPGN was reported for the first time in 1993. In some patients, the re nal clinical pattern is the most obvious (nephrotic syndrome) whereas in others liver disease or cryoglobulinaemia prevail. A risk factor of HCV infection exists in 80% of cases. Renal biopsy and scanning elect ron microscopy usually substantiate cryoglobulinaemia. Circulating cry oglobulins are most often detected, usually of type II. CH50 is decrea sed in 90% of patients and rheumatoid factors have been found in two-t hirds of patients. The cryoprecipitate contains viral RNA and anti-HCV antibodies. The viral RNA is nearly always found in the cryoprecipita te. Analysing the viral genotype does not elicit predominance of any p articular type. Viral genome detection in renal biopsy specimens appea rs to be technically difficult. Type I MPGN secondary to HCV infection appear to be improved by interferon-alpha therapy but treatment suspe nsion is immediately followed by the recurrence of viraemia and nephro tic syndrome. Serological tests to detect anti-HCV antibodies and vira l RNA by PCR in type I MPGN, so far considered as 'primary', are scarc e and produce conflicting results: there might be a link between those glomerulopathies and HCV infection in the USA and in Japan only, not in Europe.