G. Di Giorgio

Effectiveness of universal precautions in limiting nosocomial transmission of hepatitis C virus in haemodialysis units.

In spite of the high prevalence of anti-HCV positive patients in haemodialysis units (1), there are conflicting results regarding the incidence rate and, consequently, the preventive strategies. Here we report our experience with a three-year follow-up: 88 patients on ROT for at least 6 months were enrolled in three dialysis units. Mean duration of follow-up was 37.2 months. All patients enrolled were tested every 4 months with a 2nd generation antiHCV test (Elisa, Ortho); confirmation of positive samples was performed with Riba test (Ortho), RT-nested PCR was used to detect HCV RNA sequence in serum. The prevention of nosocomial transmission was set up as follows. No segregation of anti-HCV positive patients was set up, no dedicated machines were used, and no dialyzer was reused. Utmost attention was paid in applying universal precautions for prevention of community acquired infection as in Center For Disease Control Recommendation (2). The disinfection protocol for dialysis monitors included a chemical disinfection with peracetic acid or hypoclorite solution after the last dialysis session of the day, while only a washing cycle was applied between dialysis sessions. Anti-HCV antibodies were initially detected in 32 subjects (35.2%); 56 patients were seronegative (Tab. I). The prevalence of anti-HCV positive patients ranged from 18.18% to 41.37%. During the follow-up five seroconversions were observed: 1 in the first, 2 in the second, 2 in the third year (3 in the hospital center, 1 for each outside centers). Thus, mean incidence of seroconversion was 2.79% / year. All seroconverted patients but one were PCR positive and all but one had a positive Riba 2° test (one was indeterminate); two patients received blood transfusion. None of the seroconverted subjects were dialyzing on single pass monitors; three were dialyzed on the same machines of an anti-HCV positive patients: one of these was also transfused 19 months before SC; one was dialyzed next to an anti-HCV positive patient, and the last had none of these risk conditions, but was transfused 15 months before SC (Tab. II). Up to now there is no agreement on applying a segregation protocol for anti-HCV positive and negative patients as has been done for hepatitis B. However, some authors have advocated the segregation of anti-HCV positive patients (3, 4). Should an isolation protocol be accepted, there will be many clinical and organizing problems: the delay between HCV infection and detection of anti-HCV antibodies; the great variability of HCV genomes (5); when isolation was performed SC rate decreased but did not disappear (6); on the other hand, there are organizing problems: we will need up to four different facilities to dialyze patients with or without HBV and HCV infection or coinfec-

HLA System in Uremics with Cystic Diseases

We evaluated the prevalence of class I HLA antigens (A, B, C) in patients (pts) on regular dialysis treatment (RDT) affected with adult polycystic kidney diseases (APKD) (12 pts) and acquired renal cystic diseases (ARCD) (12 pts). 96 voluntary HLA-typed blood donors, randomly selected, were enrolled as healty controls. In APKD group we found the greater occurence of Bw22-Ag (p/0.004).

Cystic Diseases in Uremia and HLA System

We evaluated the prevalence of class I HLA antigen (A, B, C) in patients (pts) on regular dialysis treatment (RDT) affected with adult polycystic kidney diseases (APKD) (12 pts) and acquired renal cystic diseases (ARCD) (12 pts). 96 voluntary HLA-typed blood donors, randomly selected, were enrolled as healty controls. In APKD group we found the greater occurence of Bw22-Ag (p/0.004).