Nephrol Dial Transplant (1998) 13: 1804–1806 NephrologyDialysis

TransplantationBrief Report

Absence of HCV viraemia in anti-HCV-negative haemodialysis patients

George N. Dalekos1,2, Dimitra S. Boumba1, Kostas Katopodis3, Eleftheria Zervou1,2,George Sferopoulos3, Moses Elisaf1,3, Epameinondas V. Tsianos1 and Kostas C. Siamopoulos3

Divisions of 1Internal Medicine and 3Nephrology, Department of Internal Medicine, Medical School, University of Ioanninaand 2Blood Bank, University Hospital of Ioannina, 451 10 Ioannina, Greece

Abstract Key words: chronic haemodialysis; HCV RNA; hepat-itis C virus; viraemiaBackground. Immunologic alterations have been

reported in chronic haemodialysis (HD) patients. SomeHD patients may have, therefore, an inability to pro-duce detectable amounts of serum antibodies to

Introductionhepatitis C virus (anti-HCV ). Previous studies haveshown the presence of HCV viraemia in anti-HCV-

Patients on haemodialysis (HD) are considered to benegative HD patients (ranging from 1 to 15%).a high risk group for contracting hepatitis C virusHowever, the universal epidemiologic impact of these(HCV ) infection [1–3]. The prevalence of antibodiescases remains uncertain since there are conflictingto HCV (anti-HCV ) in HD patients ranges worldwideresults. In this context, we conducted a study in anfrom 1% in the UK to 62% in Portugal [1–3]. Thisattempt to investigate the presence of HCV viraemiavariability appears to be dependent on the particularamong anti-HCV-negative HD patients in a well-country, the strategy of precautions in various dialysisdefined geographic area of the northwestern part ofcentres, the presence of other viral markers and theGreece.use of first or second generation assays for the detectionMethods. During a 6 month period, 81 anti-HCV-of anti-HCV. In our region, where epidemiologic stud-negative HD patients were tested twice for the presenceies can be done with good accuracy [4–6 ], we haveof HCV RNA, using the reverse transcriptase poly-already reported a prevalence rate of 12–17% [7,8].merase chain reaction (RT-PCR) combined with a

However, since immunological alterations are associ-DNA enzyme immunoassay (DEIA). At the sameated with chronic HD, the possibility of an inabilitytime, periodic testing for anti-HCV by two commer-to produce detectable amounts of serum anti-HCV [9]cially available third generation assays was done. Inin the same way as is observed in transplant recipientsaddition, 15 anti-HCV-positive HD patients and 20[10] seems rational. In this context, Fernandez et al.non-HD patients with well established chronic HCV[11] in Argentina recently showed that ~13% of anti-infection used as internal controls were tested for theHCV-negative HD patients were viraemic by poly-presence of HCV RNA and anti-HCV.merase chain reaction (PCR) testing. The latter studyResults. None of the anti-HCV-negative HD patientsconfirmed previous observations, although rates varywere shown to be viraemic by the combined RT-PCRconsiderably, ranging from 1 to 15% [12–14].and DEIA method. During the same time period, allHowever, the universal epidemiologic impact of theseremained anti-HCV negative by the third generationcases in HD units remains uncertain since other authorsassays. By contrast, all the patients with known HCV-failed to reveal similar findings [15].infection were positive by the two enzyme immuno-

This study was conducted in an attempt to addressassays, whereas 13 anti-HCV-positive HD patientsthese intriguing findings by investigating the presence(86.7%) and 18 non-HD patients (90%) were viraemicof HCV RNA in a cohort of anti-HCV-negative HDby RT-PCR.patients who reside in a well-characterized geographicConclusions. This study demonstrated that routinearea in the Northwestern part of Greece [4–6 ].HCV RNA testing in anti-HCV-negative HD patients

appears not to be necessary particularly when thirdgeneration assays are used for the detection of anti- Subjects and methodsHCV.

Eighty one chronic HD patients (54 male, 27 female, ageCorrespondence and offprint requests to: Kostas C. Siamopoulos,range 17–76 years, median age 61 years) were investigatedMD, MSc, FRSH, Professor of Medicine/Nephrology, Departmentfor the presence of HCV RNA. Among them, 20 patientsof Internal Medicine, Medical School, University of Ioannina, GR

451 10 Ioannina, Greece. started HD before 1991 (the year of obligatory examination

© 1998 European Renal Association–European Dialysis and Transplant Association

HCV RNA in anti-HCV negative haemodialysis patients 1805

for anti-HCV in blood banks). The clinical and demographic Discussioncharacteristics of the patients are shown in Table 1. All ofthem were repeatedly negative by two commercially available

Contrary to what has been observed by others [11–14],third generation enzyme immunoassays for at least 1 yearthis study failed to confirm the presence of viraemiabefore the beginning of the study (Murex Diagnostics Ltd,in anti-HCV-negative HD patients. It is interesting toCentral Road Temple Hill, UK, and Abbott Laboratories,notify that the absence of HCV viraemia in this studyWiesbaden Germany). These immunoassays utilize micropl-

ate wells coated with a combination of HCV antigens from was observed even among the anti-HCV-negative HDthe putative core (structural ), protease/helicase [(NS3, non- patients who started HD before 1991 (Table 1). Thestructural ), and (NS4 non-structural )] and replicase (NS5, previous studies, however, underscored the fact thatnon-structural ) regions of the HCV. For the detection of the available serodiagnostic tests may underestimateHCV RNA, a combination of two well-established techniques the prevalence of HCV in HD patients. As possiblewas also available. The latter included the reverse transcrip- explanations, the prolonged viraemia before seroconv-tion nested PCR (RT-PCR) and a DNA enzyme immuno-

ersion to anti-HCV in HD patients [17] and theirassay (DEIA, GEN-ETI-K, Sorin Biomedica, Saluggia, Italy)inability to produce antibodies towards different HCVas described previously [16 ]. The lower detection limit byantigens, as has been shown by Lok et al. [9], probablythis assay is between 10 and 102 RNA copies present in thedue to their immunosuppression, have already beeninitial sample used for reverse transcription. The patients

were evaluated twice for the detection of HCV RNA with a discussed.time interval of 6 months. At the same time, examination The discrepancy between our findings and the previ-for anti-HCV antibodies every 2 months was done in serial ous studies [11–14] may be due to the serological testsserum samples of the patients. In addition, 15 anti-HCV- used for the detection of anti-HCV. In all of thepositive HD patients [10 male, five female, age range 20–70 previous studies, first or second generation enzymeyears, median age 55 years, duration of HD (mean±SD), immunoassays were used for the detection of anti-81.2±32.5 months] and 20 non-HD patients (10 male, 10

HCV. By contrast, in this study, two commerciallyfemale, age range 20–65 years, median age 58 years) withavailable third generation assays were used. The latterwell-established chronic HCV infection based on clinical,assays incorporate (in addition to the antigens of thelaboratory and histological assessment were used as internalprevious assays) antigen encoded by the NS5 regioncontrols in order to evaluate the accuracy of the assays used

in this study. of the HCV RNA, and contain a biochemically modi-fied C33c recombinant protein of the HCV genome. Itis believed that these enzyme immunoassays, in general,

Results are more sensitive and specific than the previous ones[3,18]. Another possible explanation may be geneticor other factors reflecting the known differences in ourAll HD patients remained anti-HCV negative by thepopulation in general [4–6,19,20].third generation enzyme immunoassays during the 6

Whatever the causes, this study provides evidencemonths period of the study. None of them was shownthat the periodic determinations of anti-HCV remainto be viraemic by the highly specific combined assaymandatory and that routine HCV RNA detection in(RT-PCR and DEIA). By contrast, all the patientsanti-HCV-negative HD patients appears rather unne-with known HCV infection tested positive for anti-cessary. The duration of our study (6 months) couldHCV by the third generation enzyme immunoassays,be considered as short to reveal the absence of HCVwhereas 13 anti-HCV-positive HD patients (86.7%)viraemia. However, taking into account our findings,and 18 non-HD patients (90%) were also viraemic byas well as the increased cost and the technical difficultythe RT-PCR.of carrying out PCR analysis, we cannot suggest thatthis scientific tool should be an additional screening

Table 1. The clinical and demographic characteristics of 81 anti- test for the possible detection of viraemia in anti-HCV-HCV negative chronic haemodialysis patients negative HD patients. In our opinion, the monitoring

of aminotransferase, even in low titres, every monthStarting time as suggested by the guidelines of the Centres for

Disease Control and Prevention to control HCV infec-Before 1991 After 1991

tion in HD centres [21], the use of third generationenzyme immunoassays for serum anti-HCV detection,

No. (M/F) 20 (10/10) 61 (44/17) the transfusional prevention of contamination in gen-Age (years) 54.2±17.9 56.7±13.2eral such as increased use of erythropoietin, the pres-Duration (months) 107.2±39.1 7.9±18.8

History of transfusion (%) 65 42.6 ence of strict criteria for the collection of blood donorsNumber of blood units transfused 10.2±14.3 3.9±1.9 by blood banks and the careful serological investi-Erythropoietin administration (%) 65 83.6 gation for anti-HCV, as well as universal measures toDuration of continuous erythropoietin

avoid viral transmission, appear to be the only reliableadministration (months) 72±12.9 35.9±9.9schedules in order to reduce the high prevalence ofHistory of increased AST or ALT

in the past year (%) 15 18 HCV in HD patients.

Data are given as mean±SD. Acknowledgements. The authors wish to thank Miss AlekaPapageorgiou for excellent secretarial assistance.AST=aspartate aminotransferase; ALT=alanine aminotransferase.

G. N. Dalekos et al.1806

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Received for publication: 13.11.97Accepted in revised form: 25.2.98