Prevalence of occult hepatitis C virus in patients with HCV-antibody positivity and serum HCV RNA negativity

Abstract EN

Introduction and aim Chronic hepatitis C infection is a global problem with an increasing burden on healthcare, particularly in Egypt.

Even with the advent of highly sensitive techniques, a subset of patients with positive hepatitis C virus antibody (HCV‑Ab) and negative HCV‑viremia remain challenging to treat.

Therefore, we tried to determine the prevalence of occult HCV infection (OCI) in peripheral blood mononuclear cells (PBMCs) of patients presenting with a positive serologic test for anti‑HCV‑Ab and negative serum HCV‑RNA‑PCR (spontaneously cleared patients) and followed up those patients.

Patients and methods Between March 2010 and March 2015, a prospective study was designed to include all consecutive patients with HCV‑Ab positivity and HCV‑RNA negativity who attended the Assiut Unit for treatment of viral hepatitis – the National Committee for Control of Viral Hepatitis.

A total of 25 patients were recruited.

Spontaneous clearance of serum HCV infection was approved on the basis of HCV‑Ab positivity using two third‑generation enzyme‑linked immunosorbent assay tests and serum HCV RNA negativity on three consecutive occasions, each 6 months apart.

Follow‑up serum HCV RNA levels were evaluated for patients with OCI every 6 months.

The RNA extraction step was performed by a protocol modified from that of the QIAamp viral RNA kits.

Blood samples for separation of PBMCs were collected from all patients.

PBMCs were obtained using Ficoll–Hypaque density gradient of EDTA anticoagulated blood according to the manufacturer’s instructions (Lymphoflot).

Detection of HCV viral load was performed with the kit supplied by Applied Biosystem (HCV RT‑PCR Kit lot No.).

Results A total of 25 patients (21 men, mean age 36.2 ± 9.1) cleared HCV spontaneously (HCV‑Ab positive and serum HCV RNA negative).

Genomic HCV RNA was detected in PBMCs of three (12%) of 25 patients.

These three patients with OCI were followed up for 18 months by measuring their serum HCV RNA using highly sensitive real‑time PCR every 6 months.

Only one patient became overt HCV with a low level of viremia.

Conclusion OCI was detected in a considerable prevalence in patients who cleared HCV spontaneously, that entails corporations of HCV-viral assay in PBMCs into the diagnostic algorithm