Phenotypic and genetic spectra of galactose mutarotase deficiency: A nationwide survey conducted in Japan.

PURPOSE: Galactose mutarotase (GALM) deficiency was first reported in 2019 as the fourth type of galactosemia. This study aimed to investigate the clinical and genotypic spectra of GALM deficiency. METHODS: This was a questionnaire-based retrospective survey conducted in Japan between February 2022 and March 2023. RESULTS: We identified 40 patients with GALM deficiency in Japan (estimated prevalence: 1:181,835). Four of 38 patients (10.5%) developed cataracts, which resolved with lactose restriction in three out of four patients. Transient transaminitis was the most common symptom (23.1%). All the patients followed lactose restriction; discontinuation of the restriction after infancy did not cause any complications. Moreover, none of the participants experienced long-term complications. Two variants, GALM NM_138801.3: c.294del and c.424G>A, accounted for 72.5% of the identified pathogenic variants. The patients showed moderately elevated blood galactose levels with lactose intake; however, the elevation was lower than that observed in galactokinase deficiency. CONCLUSIONS: GALM deficiency is characterized by a similar but milder phenotype and lower blood galactose elevation than in galactokinase deficiency. Diagnosis and initiation of lactose restriction in early infancy should be essential for prevention of cataracts, especially in cases of irreversible opacity.

Simultaneous gastric, pancreatic, and renal metastasis from poorly differentiated hepatocellular carcinoma.

Common extrahepatic metastasis sites of hepatocellular carcinoma (HCC) are the lungs, adrenal glands, and bones. Herein, we report a rare case of metastatic gastric, pancreatic, and renal tumors from HCC simultaneously, and review the relevant literature. A 75-year-old woman presented with right hypochondralgia, appetite loss, and weight loss. Computed tomography revealed suspected metastatic liver, lung, and renal tumors. A blood test revealed a leukocyte count of 26,210/µL and a high inflammatory reaction. As sepsis was suspected, the patient was referred to our hospital. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging revealed a hypovascular liver tumor that was suspected to be metastatic. Upper gastrointestinal endoscopy revealed two suspected metastatic gastric tumors. Liver and gastric tumor biopsies revealed poor carcinoma in both. The patient's condition gradually worsened and she died on day 8 of the illness. Based on autopsy findings, the patient was finally diagnosed with metastatic gastric and renal tumors originating from HCC. Additionally, a metastatic pancreatic tumor originating from the HCC was identified during autopsy. The pathological diagnosis of the pulmonary lesion was primary lung adenocarcinoma. In conclusion, HCC should be suspected in cases with multiple metastases of unknown primary lesions.

Transport and Golgi organization 2 deficiency with a prominent elevation of C14:1 during a metabolic crisis: A case report.

Mutations in transport and Golgi organization 2 homolog (TANGO2) have recently been described as a cause of an autosomal recessive syndrome characterized by episodes of metabolic crisis associated with rhabdomyolysis, cardiac arrhythmias, and neurodegeneration. Herein, we report a case of a one-and-a-half-year-old Japanese girl, born to nonconsanguineous parents, who presented with metabolic crisis characterized by hypoglycemia with hypoketonemia, rhabdomyolysis, lactic acidosis, and prolonged corrected QT interval (QTc) at the age of 6 months. Acylcarnitine analysis during the episode of crisis showed prominent elevation of C14:1, suggesting very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency. In addition, worsening rhabdomyolysis was observed after intravenous administration of L-carnitine. VLCAD deficiency was initially suspected; however, the enzyme activity in lymphocytes was only mildly decreased at the gene carrier level, and no mutation in the VLCAD gene (ADADVL) was detected. Subsequently, acylcarnitine analysis was nonspecific at 17-h fasting and almost normal during the stable phase. Eventually, a trio whole-exome sequencing revealed a compound heterozygous variant of two novel variants in the TANGO2 gene, a missense variant, and a deletion of exon 7. This is the first case of TANGO2 deficiency in Asians. Our case suggests that elevated C14:1 may be seen in severe metabolic crises and that the use of L-carnitine should be avoided during metabolic crises.

Maple syrup urine disease due to a paracentric inversion of chr 19 that disrupts BCKDHA: A case report.

Maple syrup urine disease (MSUD) is a rare autosomal recessive inherited disorder of branched-chain amino acid metabolism caused by mutations in BCKDHA, BCKDHB, and DBT that encode the E1α, E1ß, and E2 subunits of the branched-chain α-ketoacid dehydrogenase (BCKD) complex. Various MSUD-causing variants have been described; however, no structural rearrangements in BCKDHA have been reported to cause the classic MSUD phenotype. Here, we describe the classic patient with MSUD with compound heterozygous pathogenic variants in BCKDHA: a missense variant (NM_000709.3:c.757G > A, NP_000700.1:p.Ala253Thr) and a paracentric inversion disrupting Intron 1 of BCKDHA, which was identified by whole-genome sequencing and validated by fluorescence in situ hybridization. Using the sequence information of the breakpoint junction, we gained mechanistic insight into the development of this structural rearrangement. Furthermore, the establishment of junction-specific polymerase chain reaction could facilitate identification of the variant in case carrier or future prenatal/preimplantation tests are necessary.

A Case of Hepatocellular Carcinoma Successfully Resumed Atezolizumab and Bevacizumab After Associated Grade 3 Diarrhea and Grade 2 Colitis: Case Report and Literature Review.

Systemic chemotherapy has shown a significant survival benefit in patients with hepatocellular carcinoma (HCC). However, it is associated with various immune-related adverse events (irAEs). We report a case with grade 3 diarrhea and grade 2 colitis following systemic chemotherapy, successfully treated with prednisolone. An 89-year-old man was incidentally detected with a 140-mm hypervascular intrahepatic nodule on contrast-enhanced computed tomography (CECT). Washout of the contrast medium was also detected, and protein induced by vitamin K deficiency or antagonists-II (PIVKA-II) was elevated. Since the Albumin-Bilirubin (ALBI) grade was 2a without any distant metastasis, transarterial chemoembolization (TACE) was performed to treat the HCC, but several intrahepatic nodules were seen in both lobes. Therefore, the patient was treated with lenvatinib for 1 year and 4 months. A complete response according to modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria was achieved in 2 months; however, multiple hypervascular nodules were detected again. Since the ALBI grade was 1, a second round of chemotherapy with atezolizumab and bevacizumab was initiated. Although a complete response was achieved, the therapy was discontinued due to grade 3 diarrhea and grade 2 colitis after the sixth course. Based on the stool analysis and culture, CECT, and colonoscopy, the diagnosis was atezolizumab-associated colitis. Diarrhea was controlled following the oral administration of 0.5 mg/kg/day of prednisolone, and atezolizumab-bevacizumab therapy was successfully reinitiated without recurrence of colitis. The management of irAEs is important for a significant survival benefit. Systemic chemotherapy with atezolizumab and bevacizumab can be resumed despite a grade 3 irAE due to atezolizumab.

An Infant Case of Streptococcus Pneumoniae-Associated Thrombotic Microangiopathy with Heterozygous CFI Mutation and CFHR3-CFHR1 Deletion.

Thrombotic microangiopathy (TMA) is a disease that causes organ damage due to microvascular hemolytic anemia, thrombocytopenia, and microvascular platelet thrombosis. Streptococcus pneumoniae-associated TMA (spTMA) is a rare complication of invasive pneumococcal infection. In addition, atypical hemolytic uremic syndrome (aHUS) is TMA associated with congenital or acquired dysregulation of complement activation. We report the case of a nine-month-old boy with refractory nephrotic syndrome complicated by spTMA in the setting of heterozygous complement factor-I (CFI) gene mutation and CFHR3-CFHR1 deletion. He repeatedly developed thrombocytopenia, anemia with schistocytes, hypocomplementemia, and abnormal coagulation triggered by infection, which manifested clinically with convulsions and an intraperitoneal hematoma. Eculizumab (a monoclonal humanized anti-C5 antibody) provided transient symptomatic benefit including improvement in thrombocytopenia; however, he developed unexplained cardiac arrest and was declared brain dead a few days later. In this report, we highlight the diagnostic challenges of this case and the causal relationship between spTMA and complement abnormalities and consider the contribution of heterozygous mutation of CFI and CFHR3-CFHR1 deletion.

TREC/KREC Newborn Screening followed by Next-Generation Sequencing for Severe Combined Immunodeficiency in Japan.

PURPOSE: The aim of this study is to evaluate the usefulness of T cell receptor excision circle (TREC) and/or kappa-deleting recombination excision circle (KREC) measurements integrated with diagnostic next-generation sequencing (NGS) analysis using a severe combined immunodeficiency (SCID) newborn screening (NBS) program. METHODS: TREC and/or KREC values were measured in 137,484 newborns between April 2017 and December 2021 using EnLite TREC (n = 80,791) or TREC/KREC kits (n = 56,693). For newborns with positive screening results, diagnostic NGS analysis was performed with a 349-gene panel to detect genetic mutations associated with primary immunodeficiencies (PIDs). RESULTS: A total of 145 newborns (0.11%) had abnormal TREC and/or KREC values, and a genetic diagnosis was established in 2 patients with SCID (1 in 68,742 newborns) (IL2RG-SCID and reticular dysgenesis) and 10 with non-SCID PIDs with T and/or B cell deficiencies (1 in 13,748 newborns) using NGS analysis. Furthermore, TREC values of 2849 newborns were measured and confirmed the significant correlation between the results of both TREC and TREC/KREC kits (P < 0.001) and naïve T cell counts. CONCLUSIONS: We performed the first large-scale TREC and TREC/KREC NBS programs in Japan. Our NBS programs followed by the diagnostic NGS analysis for newborns with abnormal TREC and/or KREC values are useful for the early identification and rapid molecular evaluation of not only SCID but also different non-SCID PIDs.

Two Japanese patients with Noonan syndrome-like disorder with loose anagen hair 2.

Noonan syndrome-like disorder with loose anagen hair (NSLH) is a rare disease characterized by typical features of Noonan syndrome with additional findings of relative or absolute macrocephaly, loose anagen hair, and a higher incidence of intellectual disability. NSLH1 is caused by a heterozygous mutation in the SHOC2 gene on chromosome 10q25, and NLSH2 is caused by a heterozygous mutation in the Protein phosphatase one catalytic subunit beta (PPP1CB) gene on chromosome 2p23. Protein phosphatase1 (PP1), encoded by PPP1CB, forms a complex with SHOC2 and dephosphorylates RAFs, which results in activation of the signaling cascade and contribution to Noonan syndrome pathogenesis. Here, we report two genetically confirmed Japanese patients with NSLH2 having the same de novo mutation in PPP1CB presenting prominent-hyperteloric-appearing eyes and a tall forehead similar to individuals carrying a mutation in PPP1CB, c.146C > G; p.Pro49Arg, which is different from typical facial features of Noonan syndrome. They also showed short stature, absolute macrocephaly, and loose anagen hair like NSLH1: however, growth hormone deficiency often seen in NSLH1 caused by SHOC2 mutation was absent. Although a number of Noonan syndrome and NSLH1 patients have shown blunted or no response to GH therapy, linear growth was promoted by recombinant human growth hormone (rhGH) in one of our patients. Since another NSLH2 patient with good response to rhGH treatment was reported, rhGH therapy may be effective in patients with NSLH2.

Identification of a Novel Mutation in Carboxyl Ester Lipase Gene in a Patient with MODY-like Diabetes.

Maturity-onset diabetes of the young (MODY) is a form of diabetes mellitus characterized by autosomal dominant inheritance, early onset, and the absence of pancreatic autoimmune markers. MODY-causing mutations have been identified in 14 genes, and carboxyl ester lipase (CEL) has been implicated in MODY8. We report a Japanese patient with MODY who harbored a heterogeneous mutation in CEL exon 2 (NM_001807.4:c.146_147delCT; NP_001798.2:p.Ser49CysfsTer52). A 13-year-old girl experienced her first episode of diabetic ketoacidosis, during which her endogenous insulin secretion was poor. However, her insulin secretion had apparently recovered 2 months after the commencement of insulin treatment, and no further treatment was required for the following 2 years. Diabetic ketoacidosis recurred when the patient was 15 years old, when her insulin secretion was again poor. Since that time, the patient, who is now 18 years old, has been undergoing continuous insulin treatment. The large fluctuations in her insulin secretory capacity led us to suspect MODY. MODY8 patients that carry a mutation in the variable number of tandem repeats in the last exon of the CEL gene typically show pancreatic exocrine dysfunction. However, in the present case, which features premature termination, there is no involvement of exocrine dysfunction, potentially demonstrating a genotype-phenotype correlation.

Muscular Metastasis of Hepatocellular Carcinoma: Case Report and Literature Review.

There are few case reports of hepatocellular carcinoma (HCC) metastasis to the skeletal muscle. A 78-year-old man developed a mass in the right shoulder. Washout of contrast medium during contrast-enhanced ultrasonography (CEUS) in both the primary HCC and the metastatic site was detected. Several nodules were scattered throughout the liver on an autopsy. In addition, the moderately differentiated HCC had metastasized to the right teres major muscle. Rare muscular metastasis should be considered if a hepatic tumor is moderately or poorly differentiated HCC. Early washout during CEUS is consistent with a pathological diagnosis of moderately or poorly differentiated HCC.

Current status of surviving patients with arginase 1 deficiency in Japan.

Arginase 1 (ARG1) deficiency is a rare urea cycle disorder (UCD), with an estimated frequency of 1 per 2,200,000 births in Japan. Patients with ARG1 deficiency develop symptoms in late infancy or pre-school age with progressive neurological manifestations and sometimes present with severe hepatic disease. We previously investigated the status of UCDs in Japan; however, only one patient was identified as having ARG1 deficiency. Therefore, we aimed to investigate the current status of patients with ARG1 deficiency in 2018-2021 because almost 10 years have passed since the previous study. We present the disease history, clinical outcome, and treatment of five surviving patients with ARG1 deficiency and discuss the features of ARG1 deficiency in Japan. We found that clinicians often face difficulty in diagnosing ARG1 deficiency at the early stage of onset because of interpatient variability in onset time and clinical manifestations. Blood L-arginine and guanidino compounds were considered to be the major factors causing adverse neurodevelopmental outcomes. Therefore, early detection and intervention of ARG1 deficiency is essential for improved neurodevelopmental outcomes. Liver transplantation has been considered an effective treatment option that can dramatically improve the quality of life of patients, prior to the neurological manifestation of symptoms caused by ARG1 deficiency.

Influence of food on pharmacokinetics and pharmacodynamics of 4-phenylbutyrate in patients with urea cycle disorders.

Urea cycle disorders (UCDs), inborn errors of hepatocyte metabolism, cause hyperammonemia and lead to neurocognitive deficits, coma, and even death. Sodium 4-phenylbutyrate (NaPB), a standard adjunctive therapy for UCDs, generates an alternative pathway of nitrogen deposition through glutamine consumption. Administration during or immediately after a meal is the approved usage of NaPB. However, we previously found that preprandial oral administration enhanced its potency in healthy adults and pediatric patients with intrahepatic cholestasis. The present study evaluated the effect of food on the pharmacokinetics and pharmacodynamics of NaPB in five patients with UCDs. Following an overnight fast, NaPB was administered orally at 75 mg/kg/dose (high dose, HD) or 25 mg/kg/dose (low dose, LD) either 15 min before or immediately after breakfast. Each patient was treated with these four treatment regimens with NaPB. With either dose, pre-breakfast administration rather than post-breakfast administration significantly increased plasma PB levels and decreased plasma glutamine availability. Pre-breakfast LD administration resulted in a greater attenuation in plasma glutamine availability than post-breakfast HD administration. Plasma levels of branched-chain amino acids decreased to the same extent in all tested regimens. No severe adverse events occurred during this study. In conclusion, preprandial oral administration of NaPB maximized systemic exposure of PB and thereby its efficacy on glutamine consumption in patients with UCDs.

Evaluation of subclinical chronic sun damage in the skin via the detection of long-lasting ultraweak photon emission.

BACKGROUND: It is well known that solar radiation accelerates skin photoaging. To evaluate subclinical photodamage in the skin especially from the early phase of ultraviolet (UV)-induced damage, we have focused on ultraweak photon emission (UPE), also called biophotons. Our previous study reported that the amount of long-lasting UPE induced by UV, predominantly from lipid peroxidation, is a valuable indicator to assess cutaneous photodamage even at a suberythemal dose, although it was only applied to evaluate acute UV damage. The aim of this study was to further investigate whether long-lasting UPE could also be a useful marker to assess subclinical chronic sun damage in the course of skin photoaging. MATERIALS AND METHODS: Forty-three Japanese females in their 20s were recruited and were divided into two groups according to their history of sun exposure based on a questionnaire (high- and low-sun-exposure groups). Several skin properties on the cheek and outer forearm were measured in addition to UV-induced UPE. RESULTS: Among the skin properties measured, water content, average skin roughness, and the lateral packing of lipids in the stratum corneum were significantly deteriorated in the high-sun-exposure group as were changes in some skin photoaging scores such as pigmented spots and wrinkles. In addition, those skin properties were correlated with the UPE signals, suggesting the possible impact of oxidative stress on chronic skin damage. CONCLUSION: Subtle oxidative stress detected by long-lasting UPE may contribute to subclinical cutaneous damage at the beginning phase of chronic sun exposure, which potentially enhances skin photoaging over a lifetime.

Retinoids Decrease Soluble MICA Concentration by Inhibiting the Enzymatic Activity of ADAM9 and ADAM10.

BACKGROUND/AIM: The association between MHC class I polypeptide-related sequence A (MICA) and hepatocellular carcinoma (HCC) development was identified in our previous genome-wide association study. Decreasing soluble MICA (sMICA) through MICA sheddases suppression facilitates natural killer (NK) cell-mediated cytotoxicity. The expression of ADAM9 in HCC has been correlated with poor prognosis, and our recent study showed that its suppression contributes to cancer elimination by decreasing sMICA. MATERIALS AND METHODS: Human HCC cell line PLC/PRF/5 and HepG2 cells were used. sMICA levels were measured by ELISA. Expression of retinoid X receptors (RXRs) and retinoic acid receptors (RARs) was knocked down by siRNA. RESULTS: In our screening of FDA-approved drugs in vitro, retinoids were found to be efficient ADAM9 and ADAM10 inhibitors. Treatment with retinoids reduced sMICA levels in human HCC cells. Interestingly, the effects were abrogated by depletion of the retinoid receptor RXRα. CONCLUSION: Retinoids can be potential novel agents for HCC treatment.

Long-term outcome of urea cycle disorders: Report from a nationwide study in Japan.

Urea cycle disorders (UCDs) are inherited metabolic disorders with impaired nitrogen detoxification caused by defects in urea cycle enzymes. They often manifest with hyperammonemic attacks resulting in significant morbidity or death. We performed a nationwide questionnaire-based study between January 2000 and March 2018 to document all UCDs in Japan, including diagnoses, treatments, and outcomes. A total of 229 patients with UCDs were enrolled in this study: 73 males and 53 females with ornithine transcarbamylase deficiency (OTCD), 33 patients with carbamoylphosphate synthetase 1 deficiency, 48 with argininosuccinate synthetase deficiency, 14 with argininosuccinate lyase deficiency, and 8 with arginase deficiency. Survival rates at 20 years of age of male and female patients with late-onset OTCD were 100% and 97.7%, respectively. Blood ammonia levels and time of onset had a significant impact on the neurodevelopmental outcome (P < .001 and P = .028, respectively). Hemodialysis and liver transplantation did not prevent poor neurodevelopmental outcomes. While treatment including medication, hemodialysis, and liver transplantation may aid in decreasing blood ammonia and/or preventing severe hyperammonemia, a blood ammonia level ≥ 360 µmol/L was found to be a significant indicator for a poor neurodevelopmental outcome. In conclusion, although current therapy for UCDs has advanced and helped saving lives, patients with blood ammonia levels ≥ 360 µmol/L at onset often have impaired neurodevelopmental outcomes. Novel neuroprotective measures should therefore be developed to achieve better neurodevelopmental outcomes in these patients.

Novel ARG1 variants identified in a patient with arginase 1 deficiency.

We report a case of a 13-year-old boy with arginase 1 deficiency carrying a new variant in ARG1. Sanger sequencing identified the compound heterozygous variants: NM_000045.4: c.365G>A (p.Trp122*)/c.820G>A (p.Asp274Asn). Although not previously reported, the p.Asp274Asn variant is predicted to have strong pathogenicity because it is located in a highly conserved domain in the protein core and arginase activity in the patient was below measurement sensitivity.

Leukotriene receptor antagonists enhance HCC treatment efficacy by inhibiting ADAMs and suppressing MICA shedding.

In our previous genome-wide association study, we demonstrated the association between MHC class I-related chain A (MICA) and hepatocellular carcinoma (HCC) development in patients with chronic hepatitis C. Increasing membrane-bound MICA (mMICA) in cancer cells by reducing MICA sheddases facilitates natural killer (NK) cell-mediated cytotoxicity. Our recent study clarified that A disintegrin and metalloproteases (ADAM), including ADAM9, are MICA sheddases in HCC, and that the suppression of ADAMs increases mMICA, demonstrating the rationality of mMICA-NK targeted therapy. Furthermore, we showed that regorafenib suppresses ADAM9 transcriptionally and translationally. A library of FDA-approved drugs was screened for more efficient inhibitors of ADAM9. Flow cytometry evaluation of the expression of mMICA after treatment with various candidate drugs identified leukotriene receptor antagonists as potential ADAM9 inhibitors. Furthermore, leukotriene receptor antagonists alone or in combination with regorafenib upregulated mMICA, which was in turn downregulated by leukotriene C4 and D4 via ADAM9 function. Our study demonstrates that leukotriene receptor antagonists could be developed as novel drugs for immunological control and suppression of ADAM9 in HCC. Further, leukotriene receptor antagonists should be explored as combination therapy partners with conventional multi-kinase inhibitors for developing therapeutic strategies with enhanced efficacies for HCC management and treatment.

Japanese patients with mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase deficiency: In vitro functional analysis of five novel HMGCS2 mutations.

Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) deficiency is a metabolic disorder caused by mutations in the HMGCS2 gene. The present study describes the identification of four cases of HMGCS2 deficiency in Japan. Hepatomegaly and severe metabolic acidosis were observed in all cases. Fatty liver was identified in three cases, which suggested the unavailability of fatty acids. All patients presented with a high C2/C0 ratio, suggesting that the fatty acid oxidation pathway was normal during metabolic crisis. Genetic analyses revealed five rare, novel variants (p.G219E, p.M235T, p.V253A, p.S392L and p.R500C) in HMGCS2. To confirm their pathogenicity, a eukaryotic expression system and a bacterial expression system was adopted that was successfully used to obtain affinity-purified HMGCS2 protein with measurable activity. Purified M235T, S392L and R500C proteins did not retain any residual activity, whilst the V253A variant showed some residual enzymatic activity. Judging from the transient expression experiment in 293T cells, the G219E variant appeared to be unstable. In conclusion, the present study identified five novel variants of HMGCS2 that were indicated to be pathogenic in four patients affected by HMGCS2 deficiency.

A novel homozygous variant in MICOS13/QIL1 causes hepato-encephalopathy with mitochondrial DNA depletion syndrome.

BACKGROUND: Mitochondrial DNA depletion syndrome (MTDPS) is part of a group of mitochondrial diseases characterized by a reduction in mitochondrial DNA copy number. Most MTDPS is caused by mutations in genes that disrupt deoxyribonucleotide metabolism. METHODS: We performed the whole-exome sequencing of a hepato-encephalopathy patient with MTDPS and functional analyses to determine the clinical significance of the identified variant. RESULTS: Here, whole-exome sequencing of a patient presenting with hepato-encephalopathy and MTDPS identified a novel homozygous frameshift variant, c.13_29del (p.Trp6Profs*71) in MICOS13. MICOS13 (also known as QIL1, MIC13, or C19orf70) is a component of the MICOS complex, which plays crucial roles in the maintenance of cristae junctions at the mitochondrial inner membrane. We found loss of MICOS13 protein and fewer cristae structures in the mitochondria of fibroblasts derived from the patient. Stable expression of a wild-type MICOS13 cDNA in the patients fibroblasts using a lentivirus system rescued mitochondrial respiratory chain complex deficiencies. CONCLUSION: Our findings suggest that the novel c.13_29del (p.Trp6Profs*71) MICOS13 variant causes hepato-encephalopathy with MTDPS. We propose that MICOS13 is classified as the cause of MTDPS.

Decreased expression of interferon-stimulated genes in B cells of patients with chronic hepatitis C during interferon-free therapy potentially suggests the eradication of hepatitis C virus in the B cells: A cohort study.

AIMS: Hepatitis C virus (HCV) infection is monitored by the host innate immunity that includes the endogenous interferon (IFN), which up-regulates IFN-stimulated genes (ISGs). HCV is both hepatotropic and lymphotropic, but HCV replication in lymphoid cells is a controversial issue. Here, we analyzed the mRNA levels of the ISGs in B cells of HCV-infected patients during antiviral therapy and investigated the effects of viral eradication. METHODS: One hundred and eighty-one patients with chronic hepatitis C and 26 healthy volunteers were enrolled in this study. Levels of HCV RNA and mRNA of ISGs in B cells isolated from the patients were monitored before, during, and after antiviral therapy. RESULTS: HCV RNA was detected in B cells of 133/175 (76.0%) patients who achieved sustained virologic response (SVR) before therapy was started. The positive ratio of HCV RNA in B cells was higher in patients with genotype 1 and the non-major genotype of interleukin 28B. HCV RNA in B cells of most patients disappeared 1 week after antiviral therapy was started. The baseline expression of ISG mRNA was significantly higher in the patients than in the healthy volunteers. Levels of ISG mRNA were increased and remained high throughout the IFN-based therapy. In contrast, levels of ISG mRNA in patients who achieved SVR were significantly decreased 1 week after the IFN-free therapy was started and remained low during the therapy. CONCLUSIONS: These results suggested that IFN-free therapy potentially eradicated HCV in the B cells, leading to the down-regulation of endogenous ISGs. The level of ISG mRNA could be used as a marker for viral eradication in B cells.