Occult HCV infection has a predilection for specific populations such as haemodialysis (HD) patients.The exact natural course, epidemiology, pathogenesis and clinical importance of OCI are unknown. We investigated the existence of OCI among local patients undergoing routine HD at a referral hospital in Pahang, Malaysia. Methods:Serum andperipheral blood mononuclear cells (PMBCs) were collected from peripheral venous blood samples of seropositive (anti-HCV positive) and seronegative (anti-HCV negative) HD patients as well as healthy individuals (negative control group). Inclusion criteria for the seronegative patients included elevated liver enzymes. Both conventional PCR and strand-specific PCR were used to detect the viral RNA and to indicate active viral replication in PBMCs respectively. Direct DNA sequencing was done to confirm the viral HCV RNA and their genotypes. Results:In the majority (90-100%) of seropositive chronic hepatitis C patients, viral RNA was detected in both serum and PMBCs . Meanwhile, out of 22 seronegative patients, 6 (27%) showed active viral replication in PBMCs but no detectable viral RNA presence in the serum. None of the negative control group had detectable viral RNA. All seronegative patients with OCI were infected with HCV genotype 3 and two of them (2/6) had a slight elevation of their liver enzymes. Conclusion:Seronegative OCI does exist among local hemodialysis patients, with normal or persistently abnormal liver enzyme values. Further investigation is needed to study the mode of viral transmission and clinical significance of OCI in HD setting.
Mixed-genotypes hepatitis C virus (HCV) infections are normally ignored in chronic hemodialysis patients. The aim of this study is to investigate the prevalence of mixed-genotypes infections among hemodialysis patients in Pahang province, Malaysia. Reverse-transcription and polymerase chain reaction methods were performed using two different sets of primers, targeting the 5' untranslated region and nonstructural 5B region. Target region base sequences were obtained by direct sequencing. Discrepancy in outcomes from phylogenetic analysis of both regions suggests double infections. Of 40 subjects in eight hemodialysis centres, evidence of mixed-genotypes infections was found in 5 subjects (12.5%) from three different centres. Four patients were infected with mixed genotypes 3 and 1 and one with genotypes 3 and 4. Cases of mixed HCV genotypes infection were considered high among hemodialysis patients in Pahang. However, further investigation is needed to confirm whether they are true mixed infections or perhaps infection with recombinant virus and also to assess the clinicopathologic characteristics of the infection.