Anti-HCV seropositivity among haemodialysis patients of Iranian origin
Ghanbarali Rais-Jalali and
Parviz Khajehdehi
Division of Neprhology, Department of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Sir,
In spite of preventive measures, because of profound immunosuppression, haemodialysis (HD) patients are at high risk of various infections including viral hepatitis [13]. Hepatitis B and hepatitis C viruses (HCV) are transmitted mainly by parenteral route, following which, a remarkable proportion of infected cases, may progress to chronic hepatitis [35]. With the introduction of an assay detecting antibodies to HCV [6], before initiating immunization against hepatitis B in our units, we evaluated the serological status of our HD patients with regard to hepatitis B virus and HCV. In addition, we examined the relation of anti-HCV seropositivity to the number of blood transfusion, HD duration, liver function test abnormalities, and underlying cause of end-stage renal disease (ESRD).
A total of 182 patients undergoing regular HD in the two HD units of Shiraz University of Medical Sciences main teaching hospitals, for a median of 28 months (range, 1132 months), median age of 48 years (range, 1580 years), 111 men and 71 women, were studied. Patients were dialysed 2 or 3 times weekly for 4 h, using standard acetate HD techniques with cuprophane dialysers. The preventive measures in the first unit with 90 patients (55 men, 35 women) were the same for the second unit covering 92 cases (56 men, 36 women). The only difference between two HD units was that in the first unit each patient was assigned to one dialysis machine, being always dialysed with the same dialysis machine, but in the second unit, HD cases were not assigned to a particular dialysis machine. All HD patients were HIV negative. HBsAg-positive patients were dialysed in a separate room. The dialysis membranes were used only once. HD machines were bleached and rinsed between patients and treated in both units according to the manufacturers' instructions. Histories of number of blood transfusion, and drug abuse as well as the cause of ESRD, were retrospectively evaluated. None of the patients admitted having abused intravenous drugs. Overall 137 (76%) patients had received blood transfusions. ESRD was due to glomerulonephritis (38%), diabetic nephropathy (22%), pyelonephritis (9%), hypertension (8%), renal allograft rejection (6%), polycystic kidney disease (4%) and lupus (2%). The cause of ESRD was unknown in 20 (11%) cases. The fasting serum was used for liver function tests and for detection of antibodies against HCV (United Biochemical, Inc HCV ELA-2, USA). Hepatitis B surface antigen (HBsAg), antibodies to core antigen (anti-HBc) and anti-HBs were tested by an enzyme immunoassay using commercially available test kits (Abbott Diagnostics). The assays were done according to the instructions of the manufacturers. Positive results were repeated in the same serum sample and if positive were considered as truly positive. HBsAg and antibodies to HBs and HBc antigens were assessed every 3 months, while liver function tests were done monthly. The upper normal limits in AST, ALT, alkaline phosphatase and total bilirubin were 46 U/l, 40 U/l, 290 U/l and 1.3 mg/dl, respectively, a value higher than upper reference was considered abnormal. Serum albumin less than 3.5 g/dl was defined as hypoalbuminaemia. ANOVA test, Student's t test,
2 test, and Fisher's exact test, were used for statistical calculations.
Overall 10 (5.5%) patients were anti-HCV positive. One out of 90 (1.1%) HD patients in the first unit, and nine from 92 (9.8%) HD cases from second unit were anti-HCV positive, with a significant difference between the two units (P=0.025). The characteristics and results of liver function tests in relation to the anti-HCV reactivity in 182 HD patients are shown in Table 1
. A strong positive correlation between anti-HCV reactivity and HD duration was found. From 11 cases of ESRD due to renal allograft rejection, three cases were anti-HCV positive. Anti-HCV seropositivity was more common than anti-HCV seronegativity among HD patients with renal allograft rejection (P=0.0097). No significant correlation between other underlying causes of ESRD and anti-HCV seroreactivity was found.
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Table 1. Anti-HCV positivity in relation to demographic data, liver function test (LFT) abnormalities, and duration of haemodialysis among 182 haemodialysis patients of Iranian origin
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HD patients are at higher risk for development of hepatitis C infection. The overall prevalence rate of anti-HCV antibodies in HD patients is approximately 20%, with a remarkable geographic variation, and the prevalence rates ranging from 3 to 71% in various HD centres [13]. The reason for these observed differences in anti-HCV seropositivity is poorly understood. Disparities in ethnic factors, gender, prevalence of HCV subtypes, number of blood transfusion or HD duration, also differences in magnitude of preventive measures applied; and the extent of immunological derangement in the studied population, might be responsible [1,79]. However, in the present study, the rate of 5.5% anti-HCV positivity has been disclosed in HD patients of Iranian origin for the first timel. This prevalence rate is much higher than its prevalence of 0.3% in Iranian healthy blood donors, but low compared to 27.1% in the Iranian multiply transfused patients with ß-thalassaemia [10] as well as most of reported series in the medical literature. The prevalence of 5.5% anti-HCV positivity, in our HD patients, was associated with a significant difference between the two units evaluated. Similar differences in anti-HCV positivity have also been reported between units [4]. Nonetheless, the prevalence of anti-HCV seropositivity was 1.1% in our first unit and 9.8% in the second one. However, both units were blood supplied from the same blood bank, used similar preventive measures, and the dialysers were not reused in both units. The only difference between the two units was, that in the first unit each patient was always dialysed with the same dialysis machine, while this policy was not followed in the second unit. Since transmission of HCV between HD patients within dialysis unit has been reported [1,2]. Thus, our finding may indicate that cross-infection by dialysis machine was mainly responsible for significant difference between anti-HCV seropositivity within the two units. Moreover, the prevalence of anti-HCV disclosed a significant positive correlation with HD duration, but it had no significant correlation with number of blood transfusion. This finding also re-emphasizes that cross-infection through dialysis machine, rather than blood transfusion was the mode of transmission of hepatitis C virus among our HD patients.
References
-
Murthy BV, Pereira BJ. A 1990s perspective of hepatitis C, human immundeficiency virus, and tuberculosis infections in dialysis patients. Semin Nephrol 1997; 17: 346363[ISI][Medline]
-
Pujol FH, Ponce JG, Lema MC et al. High incidence of hepatitis C virus infection in haemodialysis patients in units with high prevalence. J Clin Microbiol 1996; 34: 16331636[Abstract]
-
Ozdogan M, Ozgur O, Gur G et al. Histopathological impact of hepatitis virus infection in haemodialysis patients: should liver biopsy be performed before renal transplantation? Artif Organs 1997; 21: 355358[ISI][Medline]
-
Fabrizi F, Lunghi G, Andrulli S et al. Influence of hepatitis C virus (HCV) viraemia upon serum aminotransferase activity in chronic dialysis patients. Neprhol Dial Transplant 1997; 12: 13941398[Abstract]
-
Caramelo C, Bartolome J, Albalate M et al. Undiagnosed hepatitis C virus infection in haemodialysis patients: value of HCV RNA and liver enzyme levels. Kidney Int 1996; 50: 20272031[ISI][Medline]
-
Kuo G, Choo QL, Alter HJ et al. An assay for circulating antibodies to major etiologic virus of human non-A-non-B hepatitis. Science 1989; 244: 362364[ISI][Medline]
-
Golan E, Korzets Z, Cristal-Lilov A, Ben-Tovim T, Bernheim J. Increased prevalence of HCV antibodies in dialyzed ashkenazi Jews, a possible ethnic predisposition. Neprhol Dial Transplant 1996; 11: 684686[Abstract]
-
Nakayama E, Liu JH, Akiba T, Marumo F, Sato C. Low prevalence of anti-hepatitis C virus antibodies in female haemodialysis patients without blood transfusion, a multicenter analysis. J Med Virol 1996; 48: 284288[ISI][Medline]
-
dos-Santos JP, Loureiro A, Cendorogio-Neto M, Pereira BJ. Impact of dialysis room and reuse strategies on the incidence of hepatitis C virus infection in haemodialysis units. Nephrol Dial Transplant 1996; 11: 20172022[Abstract]
-
Saber-Firoosi M, Yazdankhah S, Karbasi HT. Anti-HCV seropositivity among multiply transfused patients with ß-thalassemia major in southern Iran. Ira J Med Sci 1996; 21: 5659