Occult hepatitis C in peripheral blood mononuclear cells in thrombocytopenic patients after achieving sustained virological response with direct-acting antivirals


 Table of Contents   ORIGINAL ARTICLE Year : 2021  |  Volume : 46  |  Issue : 2  |  Page : 83-91

Occult hepatitis C in peripheral blood mononuclear cells in thrombocytopenic patients after achieving sustained virological response with direct-acting antivirals

Tamer A Elbedewy MD 1, Rasha A Elkholy2, Eslam Habba3, Sarah Ragab Abd El-Khalik4
1 Department of Internal Medicine, Faculty of Medicine, Tanta University, Tanta, Egypt
2 Department of Clinical Pathology, Faculty of Medicine, Tanta University, Tanta, Egypt
3 Department of Tropical Medicine and Infectious Diseases, Faculty of Medicine, Tanta University, Tanta, Egypt
4 Medical Biochemistry, Faculty of Medicine, Tanta University, Tanta, Egypt

Date of Submission15-Dec-2020Date of Acceptance05-Jan-2021Date of Web Publication29-Oct-2021

Correspondence Address:
Tamer A Elbedewy
Department of Internal Medicine, Faculty of Medicine, Tanta University, Tanta, 31527
Egypt
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Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/ejh.ejh_60_20

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Background/aim Occult hepatitis C virus infection (OCI) may be present in resolved hepatitis C virus (HCV) after direct-acting antivirals (DAAs). DAAs may improve thrombocytopenia after achieving sustained virological response (SVR), but some patients may be manifested with thrombocytopenia after SVR. The aim of our study was to evaluate the presence of OCI in the peripheral blood mononuclear cells (PBMCs) in thrombocytopenic patients after achieving SVR with DAAs.
Patients and methods This cross-sectional study included 32 thrombocytopenic patients who achieved SVR with DAAs and 32 HCV-infected patients who achieved SVR with DAAs without thrombocytopenia as a control group. All patients were investigated for HCV-ribonucleic acid (RNA) in PBMCs, hepatitis C virus core antigen (HCVcAg), platelet autoantibodies, and serum thrombopoietin.
Results Among thrombocytopenic, non-thrombocytopenic, and both groups, HCV-RNA in PBMCs were detected in 40.63, 6.25, and 23.44%, respectively, although HCVcAg was detected in 31.25, 3.13, and 17.19%, respectively. The comparisons between thrombocytopenic and non-thrombocytopenic patients regarding HCV-RNA in PBMCs and HCVcAg were statistically significant. Comparisons between thrombocytopenic and non-thrombocytopenic and between positive and negative OCI patients regarding serum thrombopoietin were statistically insignificant. Platelet autoantibodies were detected in 56.25% of thrombocytopenic group.
Conclusion Our study is the first to provide insights into the relationship between OCI and thrombocytopenia in patients with chronic HCV after achieving SVR with DAAs. The association between OCI and thrombocytopenia may be explained by autoimmune mechanism.

Keywords: hepatitis C virus-ribonucleic acid, hepatitis C virus core antigen, occult hepatitis C infection, peripheral blood mononuclear cells, thrombocytopenia


How to cite this article:
Elbedewy TA, Elkholy RA, Habba E, Abd El-Khalik SR. Occult hepatitis C in peripheral blood mononuclear cells in thrombocytopenic patients after achieving sustained virological response with direct-acting antivirals. Egypt J Haematol 2021;46:83-91
How to cite this URL:
Elbedewy TA, Elkholy RA, Habba E, Abd El-Khalik SR. Occult hepatitis C in peripheral blood mononuclear cells in thrombocytopenic patients after achieving sustained virological response with direct-acting antivirals. Egypt J Haematol [serial online] 2021 [cited 2021 Oct 30];46:83-91. Available from: http://www.ehj.eg.net/text.asp?2021/46/2/83/329511   Introduction Top

Hepatitis C virus (HCV) is a common viral infection affecting more than 180 million persons all over the world [1]. In 2013, Egypt was one of highest HCV endemic countries, affecting ∼14.7% of the Egyptians population [2]. HCV infects extrahepatic cells as immune system cells. HCV may be presented with extrahepatic disorders (40–70%), such as thrombocytopenia, which could represent the first manifestation [3].

HCV-associated thrombocytopenia is usually linked with hepatic inflammation and fibrosis [4]. However, HCV may be associated with thrombocytopenia even in the absence of overt hepatocellular affection [5]. The pathogenesis of HCV-associated thrombocytopenia is very complex, involving many complementary mechanisms [6].

Until now, the improvement of HCV-associated thrombocytopenia after the use of direct-acting antivirals (DAAs) is not fully understood. Some studies showed that the treatment of HCV with DAAs improves thrombocytopenia after achieving sustained virological response (SVR) even after long-term follow-up [7],[8],[9]. However, a case report showed thrombocytopenia exacerbation after the use of DAAs [10].

Occult hepatitis C virus infection (OCI) is defined as the presence of hepatitis C virus-ribonucleic acid (HCV-RNA) by PCR in hepatocytes and/or peripheral blood mononuclear cells (PBMCs) with negative serum HCV-RNA result [11]. OCI presents in two types: sero-positive OCI type (positive serum HCV antibodies and negative serum HCV-RNA) and sero-negative OCI type (both serum HCV antibodies and HCV-RNA are negative). Sero-positive OCI presents in patients who most likely have resolved HCV (after HCV antiviral treatment or spontaneously) [12]. A recent study showed that the OCI incidence was 11.33% from the patients who had achieved SVR after DAA treatment [13].

Liver biopsy remains the gold standard method for OCI diagnosis by detection of HCV-RNA in hepatocytes (100%), followed by HCV-RNA detection in PBMC (nearly 70%). Other tests can be used for OCI detection such as hepatitis C virus core antigen (HCVcAg), HCV-RNA detection in serum after ultracentrifugation, and anti-HCV core detection [11],[14].

HCVcAg is one of HCV structural proteins with a fixed sequence in all HCV genotypes. HCVcAg detection is comparable to PCR regarding the specificity and sensitivity. So, HCVcAg has the potential of replacement of viral load assays by PCR [15],[16].

OCI possibly acts as a reservoir for HCV, so OCI might be related to HCV relapse, and causing hepatocellular inflammation, fibrosis, and cirrhosis [17]. Therefore, the aim of our study to evaluate the presence of OCI in the PBMCs in thrombocytopenic patients after achieving SVR with DAAs.

  Patients and methods Top

Patients

This cross-sectional study was carried out at Internal Medicine (Hematology Unit), Tropical Medicine and Infectious Diseases, Medical Biochemistry and Clinical Pathology departments, Tanta University Hospitals, between October 2018 and October 2020. A total of consecutive 32 adult thrombocytopenic patients (moderate to severe thrombocytopenia with platelet count <75×109/l) who achieved SVR with DAAs for HCV (group I) were included, and 32 age-mathed and sex-matched chronic HCV patients who achieved SVR with DAAs without thrombocytopenia were also included in the study as a control group (group II).

Inclusion criteria

Patients aged more than 18 years who achieved SVR with DAAs for HCV (after 12 weeks) with or without thrombocytopenia were included. All patients were negative for serum HCV-RNA by PCR.

All patients had the history of treatment with sofosbuvir (400 mg) and daclatasvir (60 mg) daily for 12 weeks. All patients achieved SVR at 12 weeks after the end of treatment (SVR12). SVR12 was defined as undetectable HCV-RNA (<34 IU/ml) at 12 weeks after the end of therapy [18].

Exclusion criteria

Patients with any of the following were excluded from the study: patients who had evidence of compensated or decompensated cirrhosis; patients with portal hypertension, splenomegaly, or hepatocellular carcinoma; patients who had evidence of other chronic liver diseases; patients infected with hepatitis B virus or human immunodeficiency virus; and patients with a history of thrombocytopenia owing to any cause other than HCV. Patients using immunosuppressive therapy were also excluded.

Ethical approval

The study was carried out in agreement with the guidelines of Helsinki declaration as revised in 2013. Informed written consent was obtained from all patients before the study after complete clarification of the benefits and risks. The study protocol and the suggested informed consent were approved by the Institutional Review Board (IRB) of Faculty of Medicine, Tanta University.

Methods

All patients were subjected to the following: full history taking (age, sex, any associated comorbidities, and history of previous treatment), thorough clinical examination, radiological investigations including abdominal ultrasonography, and liver stiffness measurement by fibroscan. Bone marrow aspiration was performed in groups I (thrombocytopenic group). Routine laboratory investigations including complete blood count, liver function tests (alanine aminotransferase, aspartate aminotransferase, serum bilirubin, serum albumin, and prothrombin time), serum alpha-fetoprotein, and specific laboratory investigations, which include HCV-RNA detection by reverse transcription real-time PCR in PBMCs, platelet autoantibodies by flow-cytometry, HCVcAg, and serum thrombopoietin (TPO) levels using enzyme-linked immunosorbent assay (ELISA) Kit.

Megakaryocytes evaluation in bone marrow aspirates of thrombocytopenic group

Bone marrow was examined for the megakaryocyte number, productivity, and morphology.

Detection of direct platelet auto-antibodies by flow cytometry

Overall, 5 ml of peripheral venous blood sample was drawn into a sterile vacutainer tube containing tri-potassium ethylenediaminetetraacetic acid (K3-EDTA) and centrifugated at 100 g for 15 min for obtaining platelet-rich plasma followed by washing twice with phosphate buffer saline (PBS) containing 10 mmol/l EDTA and 0.5% bovine albumin (PBS/EDTA).

Anti-CD41α phycoerythrin labeled (Clone HIP8, Cat. No. 555467) was used to identify the platelet population and anti-human immunoglobulin G (IgG) fluorescein isothiocyanate labeled (Clone G18-145, Cat. No. 555786) was used to detect platelet auto-antibodies versus mouse isotypic monoclonal antibody as a negative control (all reagents were supplied from Becton Dickinson, Mountain View, California, USA).

For each patient, two tubes were labeled and identified as negative control and IgG, respectively. Overall, 10 µl of CD41 was added to both tubes, and 10 µl of negative isotypic control and IgG was added to their appropriate tubes, respectively. Then 100 µl of the platelet suspension was pipetted into each tube. The tubes were vortexed and incubated in the dark at room temperature for 20 min, then washed twice with PBS/EDTA buffer and resuspended in 0.5 ml of PBS/EDTA buffer and were ready for acquisition by the flow cytometer. Samples were analyzed by four-color flow-cytometry Becton Dickinson (BD) FACS Calibur instrument (Becton Dickinson, San Diego, California, USA) using the Cell Quest software (Becton Dickinson, version 3, verify software House Topsham, Maine, USA).

Identification of platelets firstly by their forward and side scatter characteristic, then gating on CD41-positive cells and the percentage of IgG positivity within the CD41 positive population was detected. Platelet autoantibodies’ positivity was defined by that the mean fluorescence intensity being higher than that of the negative isotype controls. Positivity of platelet autoantibodies indicates peripheral mechanism of thrombocytopenia.

Serum thrombopoietin and hepatitis C virus core antigen determination

Whole venous blood was collected by standard venipuncture in a tube containing clot activator/Sep. After centrifugation, serum was separated and stored at −20°C until the time of the assay. Serum TPO levels were measured using a commercially available, quantitative sandwich enzyme immunoassay technique (Human TPO, Quantikine R&D, ELISA Kit, Cat. No. DTP00B; Minneapolis, Minnesota, USA) in accordance with the manufacturer’s instructions. Optical densities were measured using a Tecan Spectra II Microplate Reader (Switzerland). The concentrations were calculated from the standard curve generated by a curve-fitting program, curve expert 1.4.

HCVcAg was measured using a commercially available, quantitative sandwich enzyme immunoassay technique (Human HCVAg, My Biosource ELISA Kit, Cat. No. MBS167758; San Diego, California, USA), in accordance with the manufacturer’s instructions. The optical density was determined using the microplate reader, and the results were considered negative if less than the calculated cutoff (1.0).

Detection of hepatitis C virus-ribonucleic acid by PCR in peripheral blood mononuclear cells

PBMCs were prepared from heparinized whole blood using Ficoll Hypaque according to the protocol described by Boyum [19]. After adjusting count to 1–5×106/ml, the PBMC pellet was stored at −80 until needed. At the time of analysis, the PBMCs pellets were thawed, and then lysing was done with the aid of the lysis buffer included in the kits. Extraction of total RNA from PBMCs was performed using total RNA extraction kit (RNeasy Mini Kit CN. 74104; Qiagen, Hilden, Germany) according to manufacturer’s protocol.

After extraction, TaqMan real-time quantitative PCR amplification reactions was performed according to manufacturer’s protocol on Applied Biosystem Step one real-time PCR instrument (Foster City, California, USA) using artus HCV RG RT-PCR (Cat .No. 4518265, Qiagen, Hilden, Germany), with a limit of detection of 34 IU/ml.

Statistical analysis

The collected data were tabulated and analyzed using SPSS, version 22 software (SPSS Inc., Chicago, Illinois, USA). Categorical data were presented as number and percentages, whereas quantitative data were expressed as mean±SD. Comparison of continuous data was made using unpaired t test. Fisher’s exact was used for comparison between categorical data. P values less than 0.05 were considered statistically significant.

  Results Top

Clinical characteristics and routine laboratory investigations

This cross-sectional study was conducted on 64 patients. They were divided into two groups. Group I included 32 thrombocytopenic patients who achieved SVR with DAAs for HCV, of whom 20 (62.5%) were males and 12 (37.5%) were females, and their ages ranged from 36 to 63 years (mean, 44.72±6.98 years). Group II included 32 age-matched and sex-matched chronic HCV-infected patients who achieved SVR with DAAs without thrombocytopenia and were included in the study as a control group, of whom 17 (53.13%) were males and 15 (46.87%) were females, and their ages ranged from 31 to 65 years (mean, 42.38±8.1 years) ([Table 1]).

Table 1 Comparison between thrombocytopenic and nonthrombocytopenic patient groups

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Comparisons between thrombocytopenic and non-thrombocytopenic patient groups (group I and group II, respectively) are shown in [Table 1]. Comparisons between positive and negative patients for OCI in thrombocytopenic patients are shown in [Table 2].

Table 2 Comparison between positive and negative occult hepatitis C virus infection patients in thrombocytopenic group

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Prevalence of occult hepatitis C virus infection

The two studied groups were enrolled to screen for OCI by detection of HCV-RNA in PBMCs by PCR and HCVcAg in serum by ELISA.

Among thrombocytopenic, non-thrombocytopenic, and both groups, HCV-RNA in PBMCs was detected in 13/32 (40.63%) patients, with a mean value of 77.96±85.96 (0.25–220) IU/104/PBMCs, 2/32 (6.25%) patients with a mean value of 10.17±13.90 (6.34–20) IU/104/PBMCs, and 15/64 (23.44%) patients with a mean value of 68.92±83.16 (0.25–220) IU/104/PBMCs, respectively ([Table 1]).

Among thrombocytopenic, non-thrombocytopenic, and both groups, HCVcAg was detected in 10/32 (31.25%) patients, 1/32 (3.13%) patients, and 11/64 (17.19%) patients, respectively ([Table 1]).

Among positive patients for HCV-RNA in PBMCs, HCVcAg was positive in 10/13 (76.92%), 1/2 (50%), and 11/15 (73.33%) in thrombocytopenic group, non-thrombocytopenic group, and both groups, respectively.

Four patients (three in group I and one in group II) were positive for HCV-RNA in PBMCs only without HCVcAg detection.

The comparisons between thrombocytopenic and non-thrombocytopenic patients regarding HCV-RNA in PBMCs and HCVcAg were statistically significant ([Table 1]). The comparisons between positive and negative patients for OCI in thrombocytopenic group regarding HCV-RNA in PBMCs and HCVcAg were statistically significant ([Table 2]).

Megakaryocytes evaluation in bone marrow aspirates of thrombocytopenic group (group I)

In thrombocytopenic group (group I), regarding megakaryocytes number, 10/32 (31.25%) patients showed increased number, 17/32 (53.13%) patients showed normal number, whereas 5/32 (15.63%) patients showed decreased number. Regarding morphological megakaryocyte abnormality, dysmegakaryopoiesis was detected in 10/32 (31.25%) patients with predominance of dwarf, hypolobulated, and hypogranular forms. Regarding megakaryocyte productivity, all patients [32/32 (100%)] showed decreased production.

In OCI thrombocytopenic patients, regarding megakaryocytes number, 7/13 (53.85%) showed increased number, 5/13 (38.46%) showed normal number, and 1/13 (7.69%) showed decreased number. Regarding megakaryocyte morphology, 7/13 (53.85%) showed dysmegakaryopoiesis, whereas the remaining showed normal megakaryocyte morphology. Regarding megakaryocyte productivity, all patients [13/13 (100%)] showed decreased production.

Serum thrombopoietin level

Regarding serum TPO level, our results showed that its mean level was 59.19±11.25 (39–81) pg/ml in thrombocytopenic group and 62.91±12.6 (42–87) pg/ml in non-thrombocytopenic group. The comparison between thrombocytopenic and non-thrombocytopenic patients regarding serum TPO was statistically insignificant ([Table 1]).

In thrombocytopenic group, serum TPO mean level was 57.38±10.46 (39–71) pg/ml in thrombocytopenic patients who were positive for OCI and 60.42±11.87 (41–81) pg/ml in those who were negative for OCI. The comparison between positive and negative patients for OCI in thrombocytopenic patients regarding serum TPO was statistically insignificant ([Table 2]).

Platelet autoantibodies

Our study showed that platelet autoantibodies were detected in 18/32 (56.25%) patients in the thrombocytopenic group (group I), 10 patients of them were positive for OCI, whereas the remaining eight patients were negative for OCI. In non-thrombocytopenic group (group II), all the patients were negative for platelet autoantibodies ([Table 1] and [Table 2]).

The comparison between thrombocytopenic and non-thrombocytopenic patients regarding platelet autoantibodies was statistically significant ([Table 1]). The comparison between positive and negative patients for OCI in thrombocytopenic group regarding platelet autoantibodies was statistically insignificant ([Table 2]).

  Discussion Top

In Egypt, HCV is still the foremost health problem regardless of the grand achievement in HCV therapy in the last decade [20]. More than 90% of chronic HCV-infected patients who received DAAs achieved SVR. Nevertheless, some patients become relapsers later [21]. OCI following SVR of successful DAA therapy has a significant clinical value to HCV patients and the whole community. So, a more precise tool of diagnosis of OCI is an urgent need. Development of novel drugs against chronic HCV, which treat the patients beyond the achievement of the current SVR, is a must [22].

Although treatment with DAAs improved HCV-associated thrombocytopenia, some patients still experience thrombocytopenia after HCV eradication from their sera. So, the aim of our study was to evaluate the presence of OCI in thrombocytopenic patients after achieving SVR with DAAs.

Accordingly, 64 patients were included in our study. They were divided into two groups. Group I included 32 thrombocytopenic patients who achieved SVR with DAAs for HCV, and group II included 32 age-matched and sex-matched chronic HCV-infected patients who achieved SVR with DAAs without thrombocytopenia and were included in the study as a control group.

Our study revealed that among thrombocytopenic, non-thrombocytopenic, and both groups, HCV-RNA in PBMCs was detected in 40.63, 6.25, and 23.44%, respectively. The comparison between thrombocytopenic and non-thrombocytopenic patients regarding HCV-RNA in PBMCs was statistically significant.

To our knowledge, this is the first study of this issue in Egypt and all over the world. Different studies had been done in different categories of patients with different OCI prevalence. OCI prevalence in general population is ∼3.3%. OCI prevalence is higher in those who achieved spontaneous or drug-induced HCV infection resolution [23]. OCI prevalence is more than 10% in many studies [24]. Wang et al. [25] assessed OCI prevalence in hepatocytes and PBMCs after achieving SVR 24 weeks after therapy, and OCI was detected in nine (15.0%) out of 60 patients in DAA-based group who achieved SVR. All these nine patients were detected in hepatocytes, but only eight (13.33%) patients were detected in PBMCs. In Egypt, Abd Alla and El Awady [17] detected a noticeably high OCI prevalence (18%) in PBMCs using PCR after achieving SVR after DAA therapy. In the study by Yousif et al. [13], OCI was found in 17/150 (11.33%) patients after achieving SVR after DAAs therapy. Hanafy et al. [26] demonstrated that HCV RNA in PBMC was positive, denoting occult HCV in 85/824 (10.3%) patients.

The reasons for the difference in the prevalence in OCI among different populations may be owing to DAA regimen, study size, patients’ characteristics, HCV genotypes, and differences in the methods used for OCI detection.

We found in our study that in thrombocytopenic, non-thrombocytopenic, and both groups, HCVcAg was detected in 31.25, 3.13, and 17.19%, respectively. The comparison between thrombocytopenic and non-thrombocytopenic patients regarding HCVcAg was statistically significant. Among positive patients for HCV-RNA in PBMCs, HCVcAg was positive in 76.92, 50, and 73.33% in thrombocytopenic group, non-thrombocytopenic group, and both groups, respectively.

Our results are comparable with Hanafy et al. [26] who demonstrated that HCVcAg was positive in 85.9% (73/85) of patients with hepatocellular carcinoma after achieving a SVR. Many studies have established the capability of HCVcAg as an indicator of viral replication similar to HCV-RNA [27],[28],[29].

In our study, four patients (three in group I and one in group II) were positive for HCV-RNA in PBMCs only without HCVcAg detection. This may be explained by the low viremic load in those patients. One limitation of HCVcAg is the lower sensitivity compared with HCV-RNA in patients with low viral load [16].

Regarding megakaryocytes evaluation in thrombocytopenic group, 53.13, 31.25, and 15.63% of patients showed normal, increased, and decreased megakaryocytes number, respectively. Dysmegakaryopoiesis was detected in 31.25% of patients. All patients showed decreased megakaryocyte production. In positive patients with OCI in thrombocytopenic group, 38.46, 53.85, and 7.69% of patients showed normal, increased, and decreased megakaryocytes number, respectively. Dysmegakaryopoiesis was detected in 53.85% of patients. All patients showed decreased megakaryocyte production.

Viral bone marrow suppression has been hypothesized to be a mechanism of development of HCV-associated thrombocytopenia [30]. However, data on bone marrow suppression by HCV are extremely limited. El Barbary et al. [31] studied 30 patients with HCV-associated thrombocytopenia, which revealed an evident depression in the colony-forming unit-megakaryocyte.

Our study showed that the comparisons between thrombocytopenic and non-thrombocytopenic and between positive and negative OCI patients in thrombocytopenic group regarding serum TPO were statistically insignificant.

Conflicting findings have also been reported about the level of TPO in HCV and liver diseases, but most of them showed decreased TPO level with the progression of liver fibrosis, such as Adinolfi et al. [32], who demonstrated that TPO levels in fibrosis stages (0–2) were significantly higher compared with fibrosis stages (3–4). In our study, there were insignificant differences between the groups regarding fibroscan. So, there are no differences regarding TPO level between groups.

Our study showed that platelet autoantibodies were detected in 56.25% of thrombocytopenic group. The comparison between thrombocytopenic and non-thrombocytopenic patients regarding platelets autoantibodies was statistically significant. The comparison between positive and negative patients for OCI in thrombocytopenic group regarding platelet autoantibodies was statistically insignificant.

Up to 40% of chronic HCV-infected patients have platelet autoantibodies [33]. Aref et al. [34] demonstrated by flow cytometry that the frequency of platelet autoantibodies in HCV thrombocytopenic patients was 86 · 7 and 83 · 3% for total and IgG platelet autoantibodies, respectively. Panzer et al. [35] demonstrated that platelet autoantibodies were detectable in 66% of HCV thrombocytopenic patients. Honma et al. [36] treated 187 patients with DAAs. Platelet autoantibodies IgG were measured before and after therapy. Overall, 171/187 (91.4%) patients had increased platelet autoantibodies IgG before therapy. Although 34/187 (18.2%) patients had thrombocytopenia, 33 (97.1%) patients had increased platelet autoantibodies IgG. After DAA therapy, platelet autoantibodies IgG decreased significantly.Eradication of HCV by DAAs decreased but not abolished the risk of autoimmune diseases. Now, it became obvious that the persistence or appearance of autoantibodies may take place in a significant percentage of patients with SVR. The cause of autoimmune disorders in HCV infection, and its persistence after natural or drug-induced HCV resolution remains an unanswered problem [37].

In OCI, HCV genomes may be found mainly in cells of immune system (lymph tropism), for example, monocytes and/or lymphocytes. Chronic HCV is always related to HCV-specific cytotoxic T-cells (CD8+) exhaustion with consecutively loss of their effector role. The impairment of circulating CD8+ T-cell function inhibits allospecific T-cell clones. After HCV resolution, CD8+ T-cell function recovery may induce autoimmune processes that could clarify immunologic and inflammatory changes [38].

Eight of our patients in thrombocytopenic group did not have HCV-RNA either in PBMCs or platelet autoantibodies, although they were manifested with thrombocytopenia, and this can be explained by probability of HCV-RNA in hepatocytes, which not examined in our study. HCV-RNA is detected in PBMCs in 70% of patients compared with HCV-RNA hepatocyte detection [14]. Moreover, some studies have demonstrated that HCV-infected patients may have other sites such as platelets, which act as a reservoir for HCV-RNA [39]. The possibility of other mechanisms such as human endogenous retroviruses was also not examined. The expression and durable activation of human endogenous retroviruses in HCV infection that does not disappear after HCV resolution by DAAs might account for a number of HCV-related complications, such as autoimmune disorder development that persist or reappear after HCV clearance [40].

The current study has a major strength, as the patients included are a homogeneous group that used the same regimen of DAAs. Our study is not without limitations; first, the study is cross-sectional, not a longitudinal one, devoid of follow-up period. Second, the number of patients was small. Third, our study lacked liver biopsy examination to certify that negative patients for HCV-RNA in PBMCs is exclusive not an OCI patient, but this technique is aggressive. Accordingly, further longitudinal, larger, and multicenters studies are necessary to overcome these limitations. Moreover, further studies will be required to assess the need for retreatment of OCI patients associated with thrombocytopenia using additional course of different DAA regimens, especially with novel more potent DAA generations.

  Conclusion Top

Our study is the first to provide insights into the relationship between OCI and thrombocytopenia in patients with chronic HCV infection after achieving SVR with DAAs. The association between OCI and thrombocytopenia may be explained by autoimmune mechanism owing to the development of platelet autoantibodies.

A complete eradication of HCV after SVR seems to be doubtful in spite of significantly improvement in DAA efficacy owing to OCI occurrence in other body compartments. Consequently, we recommend testing for OCI by HCV-RNA in PBMCs and/or HCVcAg in addition to serum HCV-RNA testing at the end of DAA therapy before confirmation of SVR.

Acknowledgements

Authors’ contributions: Concept, design, definition of intellectual content, and statistical analysis: T.A.E. Clinical studies: T.A.E. and E.H. Experimental studies: R.A.E. and S.R.A. Data acquisition, data analysis, literature search, manuscript preparation, manuscript review, and manuscript editing: T.A.E., R.A.E., E.H., and S.R.A. All authors have read and approved the final version of the manuscript.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 

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  [Table 1], [Table 2]

 

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