[Influence of cryoglobulinaemia on renal function in patients with chronic HCV infection]

HCV infection is a common cause of cryoglobulinaemia, characterized by existence of antibodies that show reversible precipitation at low temperatures. Deposition of cryoglobulines in glomerular vessels tends to induce development of membranous, or less commonly, mesangial glomerulonephritis with renal insufficiency as final consequence. Objective was investigating the existence of cryoglobulinaemia, its types and relation with renal impairment in patients chronically infected with hepatitis C virus.

The research included 36 patients (9 women and 27 men) chronically infected with hepatitis C virus at the average age 38 years. Existence and types of cryoglobulines in serum were measured using electrophoresis and then immunofixation on cryogel by the method of Bence Jones (Sebia, France). Renal functioning was estimated with reference to serum urea and creatinine concentrations, glomerular filtration rate (GFR) and serum cystatin C concentration with immunoenzymatic method.

Cryoglobulinaemia was significantly more common among patients infected with genotype 1 than 3 (71% vs. 39%; p<0.05). Types II and III of cryoglobulinaemia existed in equal frequency. The most common heavy chains were gamma immunoglobulins (42%) and the light ones--kappa (54%). Urea and creatinine concentration were normal in all patients. Three patients diagnosed with cryoglobulinaemia and infected with genotype 1 had abnormal GFR. There was dependency between cryoglobulinaemia and elevated cystatin C concentration (R=0.4; p<0.013).