ABSTRACT
Background: Occult hepatitis C virus [HCV] infection is a type of recently identified chronic infections that is evidenced only by detection of HCV- RNA in patients' liver tissue with consistently negative serum tests for antibodies to HCV and HCV-RNA
Aim: To study the prevalence of occult HCV infection among Egyptian patients with abnormal liver function tests and compare the characteristics of those patients with other patients with overt chronic hepatitis C infection
Methods: The presence of HCV-RNA was tested by reverse-transcription polymerase chain reaction [RT-PCR] in both liver tissue and peripheralblood mononuclear cells [PBMCs] for forty five patients with abnormal liver function tests. Clinical features of 27 patients with occult HCV infection [ 27 out of 45 patients who were negative for anti-HCV and serum HCV-RNA] were compared to 50 untreated patients with chronic HCV [anti-HCV antibodies and serum HCV-RNA positive], matched for age, gender, duration of abnormal liver function tests and body mass index
Results: HCV-RNA was detected in liver tissue of 27 [59.4%] out of 45 patients with abnormal liver function tests who were negative for both anti-HCV antibodies and serum HCV-RNA with abnormal liver function tests [i.e., who had occult HCV infection]. Twenty patients out of the 27 [74%] having intrahepatic HCV-RNA, had also viral RNA in their PBMCs. Regarding the biochemical characteristics there was significant impairment in classic HCV infection; serum bilirubin [P < 0.001], ALT [P = 0.009], AST [P = 0.013], alpha fetoprotein [P < 0.001], and fasting blood glucose [P < 0.008], but serum albumin, cholesterol, triglycerides and prothrombin time were significantly higher in occult HCV than chronic HCV [P <0.001]. No significant difference regarding Gamma-glutamyl transpeptidase [P< 0.10] was found. Necroinflammatory reactions, fibrosis, [P<0.0001] and cirrhosis [P = 0.03] were significantly higher in chronic HCV than occult HCV, but there was no significant difference regarding steatosis [P = 0.41]
Conclusion: Patients with abnormal liver functions may have intrahepatic HCVRNA in the absence of anti-HCV antibodies and serum HCV-RNA. Occult HCV infection is a milder disease than chronic HCV. Screening of those patients with persistently abnormal liver function for occult HCV-RNA can be firstly done by examining PBMCs