HEPATITIS-C VIRUS-INFECTIONS IN DIALYSIS CENTERS IN THE NETHERLANDS -A NATIONAL SURVEY BY SEROLOGICAL AND MOLECULAR METHODS

A national survey of hepatitis C virus (HCV) infections among dialysis patients in The Netherlands was performed. The study involved 2,653 p atients (2,108 hemodialysis patients and 545 chronic ambulatory perito neal dialysis [CAPD] patients) from 39 of the 49 dialysis centers in t he country. Patient sera were analyzed by both serological and molecul ar methods. Screening by a third-generation enzyme immunoassay (EIA) y ielded 79 reactive sera. The presence of anti-HCV antibodies was confi rmed in 70 patients by a line immunoassay, All seropositive samples we re tested by reverse transcriptase PCR, and 57 samples were found to c ontain HCV RNA. Of the nine EIA-positive and line immunoassay-negative or indeterminate samples, four were HCV RNA positive. All seronegativ e samples were screened for the presence of HCV RNA in pools of five s era. Of 2,576 antibody-negative samples, 6 contained HCV RNA. All anti body-positive and RNA-positive samples were also tested by a second se rological assay. The prevalence of HCV infections among Dutch dialysis patients as determined by serology or the presence of HCV RNA was 3% (80 of 2,653), i.e., 3.5% (73 of 2,108) in patients treated on hemodia lysis and 1.3% (7 of 545) in patients on CAPD. Of these 80 HCV-infecte d dialysis patients, 67 (84%) were HCV RNA positive, Serological scree ning alone would have diagnosed only 70 infected patients. Therefore, antibody screening combined with detection of HCV RNA should be consid ered as the ''gold standard'' for diagnosing HCV infection in dialysis patients. The prevalence of HCV-infected patients in Dutch dialysis c enters ranged from 0 to 8%, suggesting the existence of local risk fac tors for acquiring HCV infection. Genotyping analysis by reverse hybri dization line probe assay revealed the presence of genotypes la (23%), 1b (46%), 2 (3%), 2a (13%), 2b (1%), 3a (7%), and 4a (4%), In four (6 %) samples multiple genotypes were detected. The genotype distribution of HCV isolates among Dutch dialysis patients was similar to the dist ribution among nondialysis patients from the Benelux, except for subty pe la, which was significantly more prevalent among dialysis patients. In only one center, a high prevalence of an uncommon genotype was sug gestive of infection from a common source.