Type I membranoproliferative glomerulonephritis and HCV infection

Abstract. Type I membrano-proliferative glomerulo-nephritis (MPGN) is secondary to chronic bacterial, parasitic, viral (HB) infections, to autoimmune dis-orders or primary or malignant haemopathies. MPGN are thought to be linked to the deposition of immune complexes preformed in the circulation 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 renal 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 electron microscopy usually substantiate cryoglobulinaemia. Circulating cryoglobulins are most often detected, usually of type II. CH50 is decreased in 90 % of patients and rheumatoid factors have been found in two-thirds of patients. The cryoprecipitate contains viral RNA and anti-HCV antibodies. The viral RNA is nearly always found in the cryoprecip-itate. Analysing the viral genotype does not elicit predominance of any particular type. Viral genome detection in renal biopsy specimens appears to be technically difficult. Type I MPGN secondary to HCV infection appear to be improved by interferon-oc therapy but treatment suspension is immediately fol-lowed by the recurrence of viraemia and nephrotic syndrome. Serological tests to detect anti-HCV anti-bodies and viral RNA by PCR in type I MPGN, so far considered as 'primary', are scarce 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