Rare occurrence of occult hepatitis C virus in apparently uninfected injecting drug users: a two-centre, masked, case-control study

Occult hepatitis C infection identified in injection drug users with direct antiviral agents therapy and spontaneous resolution of hepatitis C virus infection

BACKGROUND

Occult hepatitis C infection (OCI) is characterized by the detection of hepatitis C virus (HCV) RNA in hepatocytes and in peripheral blood mononuclear cells (PBMCs) without detection in serum. We aimed to evaluate OCI in drug and no drug users who achieved sustained virological response (SVR) after therapy with direct-acting antivirals (DAAs) and with HCV spontaneous resolution.

METHODS

Twenty-four patients in the AVP group (who achieved a SVR after DAAs therapy), 13 in the NAVP group (with HCV spontaneous resolution) and 7 HCV-RNA positive patients (CPP, control positive group) were included in the study. HCV/OCI-RNA was screened in serum and PBMCs samples of the patients by ddPCR for OCI patients' identification. Plasma and red blood cells (RBCs) samples of the patients were also evaluated for HCV/OCI-RNA detection by ddPCR.

RESULTS

OCI was presented in injection drug users (IDUs) in the AVP (20.8%) and NAVP (23.1%) groups by ddPCR with a higher statistically significant percentage detected in RBCs samples of the patients in the AVP group comparatively to NAVP (p<0.01) and CPP (p < 0.05) groups.

CONCLUSION

OCI was identified in IDUs patients of the AVP and NAVP groups by ddPCR. These results suggest that OCI patients in the AVP group might not be entirely cured, and that OCI patients in the NAVP group were not identified at clinical evaluation time when just serum samples were analysed. A higher percentage of HCV/OCI-RNA was detected in RBCs samples. Overall results recommends that HCV/OCI identification in patients with DAAs therapy and spontaneous resolution of HCV infection should be studied more accurately in future and in larger patient groups if possible. Additionally, suggest also PBMCs and RBCs samples as predictors for HCV/OCI diagnosis and management.

[Low concentrations of hepatitis C virus RNA in serologically mild infection.]

Occult HCV infection (OCI) provides significant interest recently. HCV RNA in this case can be detected not in plasma, but in blood cells and/or in liver tissue. In case of antibody genesis impairment anti-HCV detection may lead to negative or "uncertain" result. The aim of the study was to estimate infection type in blood donors and patients with hematological diseases by exploration of samples with uncertain anti-HCV detection results. Blood samples of 30 180 potential blood donors' and 4322 patients with hematological diseases were tested. Comparative analysis of wide pattern of HCV markers was performed. 33 blood donors and 42 patients were enrolled in follow-up examination. Uncertain results of Anti-HCV detection in donors' samples were in 0.18% of cases. Follow-up examination of 33 donors provided discordant results using immunochemiluminescence assay and ELISA. 15.2% donors' samples contained HCV RNA in low concentration. Follow-up observation of 42 patients with incomplete antiviral antibody pattern showed HCV RNA presence in 40.5% cases (21.4% high viremia and 19.0% low viremia). Samples with low RNA concentration contained low titers of anti-core antibodies. Samples with high titers of anti-core antibodies contained high HCV RNA level. Uncertain results of anti-HCV in 15.2% of potential blood donors' samples were confirmed by detection of HCV RNA in low concentration. It proved OCI presence in these individuals and called for testing for wide pattern of HCV markers in addition to routine screening. Patients with hematological diseases showed low level of HCV RNA along with low titers of antibodies against one or two viral antigens.

Molecular diagnosis of occult hepatitis C virus infection in Iranian injection drug users

Occult HCV infection (OCI) has been described as the presence of hepatitis C virus (HCV) genomic RNA in hepatocytes and/or peripheral blood mononuclear cell (PBMC) specimens and the lack of HCV genomic RNA and anti-HCV antibodies (Abs) in plasma samples. Injection drug users (IDUs) are the most important high-risk group for infection with blood-borne viruses, particularly HCV. The purpose of this study was to determine the presence of OCI in IDUs. A prospective cross-sectional study of 126 consecutive Iranian IDUs was performed from March 2017 to January 2018. PBMCs were separated from blood samples from the participants, and after extraction of the viral RNA from the plasma and PBMC specimens, HCV RNA was detected in the samples using RT-nested PCR by amplification of the 5'-NTR of HCV. HCV genotyping was carried out using restriction a fragment length polymorphism (RFLP) assay. The viral RNA was amplified using RT-nested PCR with specific primers for the NS5B gene, and the PCR products were sequenced to confirm the results obtained by HCV RNA detection and HCV genotyping. Out of the 126 IDUs studied, 105 (83.3%) were negative for anti-HCV Abs and HCV RNA in plasma samples, whereas HCV RNA was detected in the PBMC samples of six (5.7%) participants, indicating that these individuals had OCI. Moreover, HCV genomic RNA was detected in PBMC samples from five (23.8%) of the 21 IDUs studied who were positive for anti-HCV Abs and negative for HCV genomic RNA in plasma specimens. These IDUs also had OCI. The HCV genotypes in the PBMC samples from the subjects with OCI were determined. Six (54.5%) subjects were infected with HCV subtype 3a, and five (45.5%) were infected with HCV subtype 1a. This study showed that 8.7% of the Iranian IDUs had OCI, and therefore, a study focusing on the diagnosis of OCI in these individuals can be valuable and informative.

Prevalence of occult hepatitis C virus infection in Iranian patients with beta thalassemia major

Occult hepatitis C virus infection (OCI) is a new pathological form of chronic hepatitis virus (HCV) infection characterized by the presence of HCV RNA in liver biopsy and/or peripheral blood mononuclear cell (PBMC) specimens and the absence of HCV RNA and anti-HCV antibodies (Abs) in plasma samples. β-thalassemia major is a hereditary recessive blood disease with deficiency in the hemoglobin beta chain. Thalassemic patients need blood transfusion therapy; repeated blood transfusion increases the risk of viral blood-borne infection. The aim of this study was to determine the prevalence of OCI in Iranian patients with β-thalassemia major. From February 2015 to November 2015, a total of 147 Iranian patients with β-thalassemia major were enrolled in this cross-sectional study. After extraction of viral RNA from the plasma and PBMC samples, HCV genomic RNA in the specimens was amplified by RT-nested PCR using primers from the 5'-UTR. The HCV genotypes of the positive specimens were tested using the RFLP assay. To confirm the HCV genotypes, the 5'-UTR fragment was amplified and cloned into the pJET1.2/blunt cloning vector and then sequenced. Out of 147 patients, 106 (72.1 %) were negative for anti-HCV Abs and HCV RNA. HCV RNA was found in PBMC specimens of six (5.7 %) patients, from a total of 106 patients with undetectable plasma HCV RNA and anti-HCV Abs. Therefore, six out of 106 patients had OCI. HCV genotyping revealed that three patients were infected with HCV subtype 1b, two patients were infected with HCV subtype 3a, and one patient was infected with HCV subtype 1a. These results revealed that Iranian patients with beta-thalassemia major might have OCI. Therefore, it seems that the design of a study to identify this infection in patients with β-thalassemia major would provide valuable information.

Occult HCV Infection: The Current State of Knowledge

Context

Occult HCV infection (OCI) is defined as the presence of HCV-RNA in hepatocytes and the absence of HCV in the serum according to usual tests. We aimed to define OCI and provide information about the currently available diagnostic methods. Then we focus on specific groups that are at high risk of OCI and finally investigate immune responses to OCI and the available treatment approaches.

Evidence Acquisition

PubMed, Scopus and Google Scholar were comprehensively searched with combination of following keywords: “occult”, “hepatitis C virus” and “occult HCV infection”. The definition of OCI, diagnostic methods, specific groups that are at high risk and available treatment approaches were extract from literature. An analysis of available articles on OCI also was done based on Scopus search results.

Results

OCI has been reported in several high-risk groups, especially in hemodialysis patients and subjects with cryptogenic liver disease. Furthermore, some studies have proposed a specific immune response for OCI in comparison with chronic hepatitis C (CHC).

Conclusions

With a clinical history of approximately 11 years, occult HCV infection can be considered an occult type of CHC. Evidences suggest that considering OCI in these high-risk groups seems to be necessary. We suggest that alternative diagnostic tests should be applied and that there is a need for the participation of all countries to determine the epidemiology of this type of HCV infection. Additionally, evaluating OCI in blood transfusion centers and in patients who receive large amounts of blood and clotting factors, such as patients with hemophilia, should be performed in future projects.

Hepatitis C and leptospirosis: simultaneous acute infections or recurrence of occult hepatitis C

People who inject drugs are vulnerable to several infections. To the best of our knowledge, this is the first case report of a simultaneous diagnosis of leptospirosis and acute infection or recurrence of occult hepatitis C in an HIV-infected drug user. We report a case of a 47-year-old Caucasian man with HIV infection, on antiretroviral therapy, and with a history of hepatitis C (positive anti-hepatitis C virus (HCV) and HCV RNA persistently negative) who was admitted with febrile acute hepatitis. He was a former injecting drug user, on opioid substitution therapy, who relapsed to injection drug use 3 weeks prior to admission. Work up revealed positive HCV RNA and Leptospira DNA in his urine. Four weeks later he had an undetectable HCV load, and also at 6 months of follow-up. This case highlights the presence of two concomitant infectious aetiologies of acute hepatitis in an HIV-infected drug user.

A New Twist to a Chronic HCV Infection: Occult Hepatitis C

Background. The prevalence of occult hepatitis C infection (OCI) in the population of HCV-RNA negative but anti-HCV positive individuals is presently unknown. OCI may be responsible for clinically overt recurrent disease following an apparent sustained viral response (SVR) weeks to years later. Purpose. To review the available current literature regarding OCI, prevalence, pathogenic mechanisms, clinical characteristics, and future directions. Data Sources. Searching MEDLINE, article references, and national and international meeting abstracts for the diagnosis of OCI (1990-2014). Data Synthesis. The long-term followup of individuals with an OCI suggests that the infection can be transient with the loss of detectable HCV-RNA in PPBMCs after 12-18 months or alternatively exist intermittently and potentially long term. The ultimate outcome of HCV infection is decided by interplay between host immune responses, antiviral therapies, and the various well-identified viral evasion mechanisms as well as the presence of HCV infection within extrahepatic tissues. Conclusion. The currently widely held assumption of a HCV-cure in individuals having had "SVR" after 8-12 weeks of a course of DAA therapy as recently defined may not be entirely valid. Careful longitudinal followup utilizing highly sensitive assays and unique approaches to viral isolation are needed.

Seronegative occult hepatitis C virus infection: clinical implications

Occult hepatitis C virus infection (OCI) was first described in anti-HCV and serum HCV-RNA negative patients with abnormal values of liver enzymes but who presented HCV-RNA in liver and in peripheral blood mononuclear cells. Up to now, two types of OCI are recognized: seronegative OCI (anti-HCV and serum HCV-RNA negative) and seropositive OCI (anti-HCV positive and serum HCV-RNA negative). The concept of OCI is still a matter of debate, probably because both types of OCI are not considered as different entities. This review focuses on seronegative OCI. The existence of seronegative OCI has been documented all around the world with the implication of different HCV genotypes (1-4). Seronegative OCI is associated with cryptogenic chronic hepatitis and liver cirrhosis and it may be involved in the appearance of hepatocellular carcinoma. Also seronegative OCI may increase the histological liver damage in chronic hepatitis B and in HIV-infected patients. It may have a negative influence in the natural history of hemodialysis patients and in immune-mediated glomerulonephritis. Seronegative OCI has been detected also in patients with haematological diseases, among healthy subjects and in drug users. Other publications indicate the potential infectivity of seronegative OCI in the setting of family members, sexual partners and liver transplantation. In summary, seronegative OCI may play a role in liver diseases and other human pathologies and may be present in healthy people but larger studies are needed to confirm these findings.