Qualitative and quantitative muscle ultrasound in patients with Duchenne muscular dystrophy: Where do sonographic changes begin?

OBJECTIVE: The number of studies investigating and understanding the disease mechanisms of Duchenne muscular dystrophy (DMD) in human clinical trials have increased substantially over the last decade. Suitable clinical instruments for the measurement of disease progress and drug efficiency are mandatory, but currently not available, especially in the youngest patients. The aim of this study was to detect a reproducible pattern of muscle involvement in early stages potentially preceding evidence of motor regression. MATERIAL AND METHODS: A cohort of 25 DMD patients aged 1-6 years at the first presentation were examined at multiple timepoints and compared with age-matched healthy controls. Muscle ultrasound was quantified using computer-analyzed gray scale levels (GSL) and blinded visual rating, using a modified Heckmatt scale. RESULTS: Changes in muscle echogenicity in DMD patients occurred very early, clearly preceding motor regression and in some cases, even before the motor plateau phase was reached. Visual rating and GSL identified the earliest changes in the proximal adductor magnus muscle. CONCLUSION: Muscle ultrasound can be used as an additional method to assess the disease progression and for decision-making in paucisymptomatic DMD patients. Sonographic changes in the ad-ductor magnus muscle seem to be the first detectable changes with a recognisable pattern.

Antiepileptic therapy approaches in KCNQ2 related epilepsy: A systematic review.

BACKGROUND: KCNQ2 related disorders comprise both benign seizure disorders and early onset epileptic encephalopathies. Especially within the latter group, patients suffer from refractory seizures to standard antiepileptic drugs and developmental delay. Besides the hope of personalized medical approaches to treat the recently unraveled large amount of genetic channelopathies, there are sparse systematic data on treatment responses in KCNQ2 related epilepsy in larger cohorts. METHODS: We searched PubMed using the free text term search 'KCNQ2 AND Epilepsy' and identified additional records using PubMed Medical Subject Headings (MeSH). Based on patients' clinical information about their therapy they were assigned to one of four groups: 'seizure freedom', 'responder', 'successful therapy', and 'unsuccessful therapy'. RESULTS: Out of 52 studies, 217 subjects were eligible for further data analyses. 133 patients were classified as 'benign' seizure disorders whereas 84 patients were classified as 'Early Onset Epileptic Encephalopathy (EOEE)'. In the 'benign' group, 92.5% of patients became seizure free while 3.8% did not respond to treatment. In contrast 65.5% of patients in the 'EOEE' group were reported seizure free, while 14.3% showed no treatment success (p = 0.003). Spontaneous seizure remission (without medication) was 30.1% in the 'benign' group. Phenobarbital and sodium channel blockers most often lead to seizure freedom in patients with a 'benign' course. In patients with 'EOEE' seizure freedom was more likely achieved when receiving sodium channel blockers. CONCLUSIONS: Seizures associated with mutations within the voltage gated potassium channel KCNQ2 are well controlled by medical treatment in patients with 'benign' courses and moderately well in patients with the 'EOEE' group. A significant number of patients in the 'benign' group may experience seizure freedom spontaneously. Phenobarbital might be considered in benign courses, while sodium channel blockers seem appropriate for both 'benign' and 'EOEE' patients.

Early-Onset Myopathies: Clinical Findings, Prevalence of Subgroups and Diagnostic Approach in a Single Neuromuscular Referral Center in Germany.

BACKGROUND: Early-onset myopathies are a heterogeneous group of neuromuscular diseases with broad clinical, genetic and histopathological overlap. The diagnostic approach has considerably changed since high throughput genetic methods (next generation sequencing, NGS) became available. OBJECTIVE: We present diagnostic subgroups in a single neuromuscular referral center and describe an algorithm for the diagnostic work-up. METHODS: The diagnostic approach of 98 index patients was retrospectively analysed. In 56 cases targeted sequencing of a known gene was performed, in 44 patients NGS was performed using large muscle specific panels, and in 12 individuals whole exome sequencing (WES) was undertaken. One patient was diagnosed via array CGH. Clinical features of all patients are provided. RESULTS: The final diagnosis could be found in 63 out of 98 patients (64%) with molecular genetic analysis. In 55% targeted gene sequencing could establish the genetic diagnosis. However, this rate largely depended on the presence of distinct histological or clinical features. NGS (large myopathy-related panels and WES) revealed genetic diagnosis in 58.5% (52% and 67%, respectively). The genes detected by WES in our cohort of patients were all covered by the panels. Based on our findings we propose an algorithm for a practical diagnostic approach.Prevalences:MTM1- and LAMA2-patients are the two biggest subgroups, followed by SEPN1-, RYR1- and Collagen VI-related diseases. 31% of genetically confirmed cases represents a group with overlap between "congenital myopathies (CM)" and "congenital muscular dystrophies (CMD)". In 36% of the patients a specific genetic diagnosis could not be assigned. CONCLUSIONS: A final diagnosis can be confirmed by high throughput genetic analysis in 58.5% of the cases, which is a higher rate than reported in the literature for muscle biopsy and should in many cases be considered as a first diagnostic tool. NGS cannot replace neuromuscular expertise and a close discussion with the geneticists on NGS is mandatory. Targeted candidate gene sequencing still plays a role in selected cases with highly suspicious clinical or histological features. There is a relevant clinical and genetic overlap between the entities CM and CMD.

[Epilepsy-new diagnostic tools, old drugs? : Therapeutic consequences of epilepsy genetics]. / Epilepsie ­ neue Diagnostik, alte Medikamente? : Die Konsequenzen der Epilepsiegenetik.

BACKGROUND: Recent advances in the field of epilepsy genetics have led to an increased fraction of patients with epilepsies where the etiology of the disease could be identified. Nevertheless, there is some criticism regarding the use of epilepsy genetics because in many cases the identification of a pathogenetic mutation does not lead to an adaptation of therapy or to an improved prognosis. In addition, the interpretation of genetic results might be complicated due to the considerable numbers of variants of unclear significance. OBJECTIVE: This publication presents the arguments in favour of a broad use of genetic investigations for children with epilepsies. Several diseases where a genetic diagnosis does in fact have direct therapeutic consequences are mentioned. In addition, the indirect impact of an established etiology, encompassing the avoidance of unnecessary diagnostic measures, possibility of genetic counselling, and the easing of the psychologic burden for the caregivers, should not be underestimated. CONCLUSION: The arguments in favour of broad genetic diagnostics prevail notwithstanding the lack of relevant new developments regarding the therapy.

Benzyl-substituted metallocarbene antibiotics and anticancer drugs.

Benzyl-substituted metallocarbene compounds synthesised by our group and others during the past 5 years give a new perspective on their activity as antibiotic and antitumoral drugs. N-heterocyclic carbenes containing an imidazole core were functionalised and their transition metal complexes (M = Ag, Au, Cu, Ru) have shown promising antibacterial as well as anticancer activity in vitro and in vivo. IC50 values in the nanomolar region or antibacterial activity comparable to conventional antibiotics lead the way towards novel drug candidates.

Cell type-dependent pathogenic functions of overexpressed human cathepsin B in murine breast cancer progression.

The cysteine protease cathepsin B (CTSB) is frequently overexpressed in human breast cancer and correlated with a poor prognosis. Genetic deficiency or pharmacological inhibition of CTSB attenuates tumor growth, invasion and metastasis in mouse models of human cancers. CTSB is expressed in both cancer cells and cells of the tumor stroma, in particular in tumor-associated macrophages (TAM). In order to evaluate the impact of tumor- or stromal cell-derived CTSB on Polyoma Middle T (PyMT)-induced breast cancer progression, we used in vivo and in vitro approaches to induce human CTSB overexpression in PyMT cancer cells or stromal cells alone or in combination. Orthotopic transplantation experiments revealed that CTSB overexpression in cancer cells rather than in the stroma affects PyMT tumor progression. In 3D cultures, primary PyMT tumor cells showed higher extracellular matrix proteolysis and enhanced collective cell invasion when CTSB was overexpressed and proteolytically active. Coculture of PyMT cells with bone marrow-derived macrophages induced a TAM-like macrophage phenotype in vitro, and the presence of such M2-polarized macrophages in 3D cultures enhanced sprouting of tumor spheroids. We employed a doxycycline (DOX)-inducible CTSB expression system to selectively overexpress human CTSB either in cancer cells or in macrophages in 3D cocultures. Tumor spheroid invasiveness was only enhanced when CTSB was overexpressed in cancer cells, whereas CTSB expression in macrophages alone did not further promote invasiveness of tumor spheroids. We conclude that CTSB overexpression in the PyMT mouse model promotes tumor progression not by a stromal effect, but by a direct, cancer cell-inherent mode of action: CTSB overexpression renders the PyMT cancers more invasive by increasing proteolytic extracellular matrix protein degradation fostering collective cell invasion into adjacent tissue.

The role of the intrinsic FAS pathway in Titanocene Y apoptosis: The mechanism of overcoming multiple drug resistance in malignant leukemia cells.

Despite the advantages in the outcome of patients with acute lymphoblastic leukemia, 25% of the affected children suffer relapses. As the response to chemotherapy is essentially determined by the development of cellular drug resistance, new drugs that are capable to overcome resistance to conventional chemotherapeutics are urgently needed. With regard to this demand, we investigated the titanium-based anticancer drug Titanocene Y. Treatment with Titanocene Y leads to inhibition of tumour cell proliferation and induces apoptosis in established cell lines of leukemia, lymphoma and melanoma. The extrinsic pathway appears to be responsible, at least in part, for the effect: cell death is partly inhibited in BJAB cells overexpressing a dominant negative Fas-associated death domain (FADD) mutant and via real time PCR we found a significant up-regulation of Fas ligand in the affected cells. Apoptosis is triggered regardless of the expression of anti-apoptotic Bcl-2 and pro-apoptotic smac and the agent is also effective on cells that are multidrug resistant due to overexpression of P-gp. In combination with vincristine impressive synergistic effects could be observed, exposing Titanocene Y as a possible component for polychemotherapy. Taken together, Titanocene Y turns out to be a promising candidate for anti-tumour therapy, especially for the treatment of multidrug resistant malignancies.

Lysosomal membrane permeabilization and cathepsin release is a Bax/Bak-dependent, amplifying event of apoptosis in fibroblasts and monocytes.

Apoptotic stimuli have been shown to trigger lysosomal membrane permeability (LMP), leading to the release of cathepsins, which activate death signaling pathways in the cytosol. However, it is unknown whether this process is an initiating or amplifying event in apoptosis. In this study, we used fibroblasts and monocytes exposed to etoposide, ultraviolet light, FasL or deprived of interleukin-3 (IL-3) to show that LMP and the cytosolic release of cathepsins B, L and D consistently depends on Bax/Bak and components of the apoptosome. Neither Bax nor Bak resided on the lysosomes, indicating that lysosomes were not directly perforated by Bax/Bak but by effectors downstream of the apoptosome. Detailed kinetic analysis of cells lacking cathepsin B or L or treated with the cysteine protease inhibitor, E64d, revealed a delay in these cells in etoposide- and IL-3 deprivation-induced caspase-3 activation and apoptosis induction but not clonogenic survival, indicating that cathepsins amplify rather than initiate apoptosis.

Deficiency for the cysteine protease cathepsin L promotes tumor progression in mouse epidermis.

To define a functional role for the endosomal/lysosomal cysteine protease cathepsin L (Ctsl) during squamous carcinogenesis, we generated mice harboring a constitutive Ctsl deficiency in addition to epithelial expression of the human papillomavirus type 16 oncogenes (human cytokeratin 14 (K14)-HPV16). We found enhanced tumor progression and metastasis in the absence of Ctsl. As tumor progression in K14-HPV16 mice is dependent on inflammation and angiogenesis, we examined immune cell infiltration and vascularization without finding any effect of the Ctsl genotype. In contrast, keratinocyte-specific transgenic expression of cathepsin V, the human orthologue of mouse Ctsl, in otherwise Ctsl-deficient K14-HPV16 mice restored the phenotype observed in the control HPV16 skin. To better understand this phenotype at the molecular level, we measured several oncogenic signal transduction pathways in primary keratinocytes on stimulation with keratinocyte-conditioned cell culture medium. We found increased activation of protein kinase B/Akt and mitogen-activated protein kinase pathways in protease-deficient cells, especially if treated with media conditioned by Ctsl-deficient keratinocytes. Similarly, the level of active GTP-Ras was increased in Ctsl-deficient epidermis. We conclude that Ctsl is critical for the termination of growth factor signaling in the endosomal/lysosomal compartment of keratinocytes and, therefore, functions as an anti-tumor protease.

Synthesis and cytotoxicity studies of new morpholino-functionalised and N-heteroaryl-substituted titanocene anticancer drugs.

From the carbolithiation of 6-morpholino fulvene (3) and different lithiated nitrogen containing heterocycles (2-N-methylimidazolyl, 2-N-(N,N-dimethylamino)methyl-imidazolyl, and 2-N-methylindolyl), the corresponding lithium cyclopentadienide intermediate (4a-c) was formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl(4) resulting in morpholino-functionalised titanocenes 5a-c. When these titanocenes were tested against LLC-PK cells, the IC(50) values obtained were of 24, 36, and 41 microM respectively. The most cytotoxic titanocene in this paper (5a) with an IC(50) value of 24 microM is found to be almost ten times less cytotoxic than cis-platin, which showed an IC(50) value of 3.3 microM when tested on the epithelial pig kidney LLC-PK cell line, and approximately 2 times less cytotoxic than its dimethylamino-functionalised analogue. Encouragingly however, the IC(50) value obtained for titanocene 5a is approximately 100 times better than titanocene dichloride itself.

A bispecific diabody directed against prostate-specific membrane antigen and CD3 induces T-cell mediated lysis of prostate cancer cells.

BACKGROUND: Although cancer of the prostate is one of the most commonly diagnosed cancers in men, no curative treatment currently exists after its progression beyond resectable boundaries. Therefore, new agents for targeted treatment strategies are needed. Cross-linking of tumor antigens with T-cell associated antigens by bispecific monoclonal antibodies have been shown to increase antigen-specific cytotoxicity in T-cells. Since the prostate-specific membrane antigen (PSMA) represents an excellent tumor target, immunotherapy with bispecific diabodies could be a promising novel treatment option for prostate cancer. METHODS: A heterodimeric diabody specific for human PSMA and the T-cell antigen CD3 was constructed from the DNA of anti-CD3 and anti-PSMA single chain Fv fragments (scFv). It was expressed in E. coli using a vector containing a bicistronic operon for co-secretion of the hybrid scFv V(H)CD3-V(L)PSMA and V(H)PSMA-V(L)CD3. The resulting PSMAxCD3 diabody was purified from the periplasmic extract by immobilized metal affinity chromatography (IMAC). The binding properties were tested on PSMA-expressing prostate cancer cells and PSMA-negative cell lines as well as on Jurkat cells by flow cytometry. For in vitro functional analysis, a cell viability test (WST) was used. For in vivo evaluation the diabody was applied together with human peripheral blood lymphocytes (PBL) in a C4-2 xenograft-SCID mouse model. RESULTS: By Blue Native gel electrophoresis, it could be shown that the PSMAxCD3 diabody is mainly a tetramer. Specific binding both to CD3-expressing Jurkat cells and PSMA-expressing C4-2 cells was shown by flow cytometry. In vitro, the diabody proved to be a potent agent for retargeting PBL to lyze C4-2 prostate cancer cells. Treatment of SCID mice inoculated with C4-2 tumor xenografts with the diabody and PBL efficiently inhibited tumor growth. CONCLUSIONS: The PSMAxCD3 diabody bears the potential for facilitating immunotherapy of prostate cancer and for the elimination of minimal residual disease.

Substituted titanocenes induce caspase-dependent apoptosis in human epidermoid carcinoma cells in vitro and exhibit antitumour activity in vivo.

Titanocene compounds are a novel series of agents that exhibit cytotoxic effects in a variety of human cancer cells in vitro and in vivo. In this study, the antiproliferative activity of two titanocenes (Titanocenes X and Y) was evaluated in human epidermoid cancer cells in vitro. Titanocenes X and Y induce apoptotic cell death in epidermoid cancer cells, with IC50 values that are comparable to cisplatin. Characterisation of the cell death pathway induced by titanocene compounds in A431 cells revealed that apoptosis is preceded by cell cycle arrest and the inhibition of cell proliferation. The induction of apoptosis is dependent on the activation of caspase-3 and -7 but not caspase-8. Furthermore, the antitumour activity of Titanocene Y was tested in an A431 xenograft model of epidermoid cancer. Results indicate that Titanocene Y significantly reduced the growth of A431 xenografts with an antitumour effect similar to cisplatin. These results suggest that titanocenes represent a novel series of promising antitumour agents.

Novel titanocene anti-cancer drugs and their effect on apoptosis and the apoptotic pathway in prostate cancer cells.

Advanced prostate cancer is not curable by current treatment strategies indicating a significant need for new chemotherapeutic options. Highly substituted ansa-titanocene compounds have shown promising cytotoxic activity in a range of cancers. The objectives of this study are to examine the effects of these titanocene compounds on prostate cancer cells. Prostate cell lines were treated with three novel titanocene compounds and compared to titanocene dichloride and cisplatin. Percent apoptosis, viability and cell cycle were assessed using propidium iodide DNA incorporation with flow cytometry. Cytochrome C was assessed by western blotting of mitochondrial and cytoplasmic fractions. Apoptosis Inducing Factor was assessed by confocal microscopy. These novel compounds induced more apoptosis compared to cisplatin in a dose dependent manner. Compound Y had the most significant effect on cell cycle and apoptosis. Despite the release of cytochrome C from the mitochondrial fraction there was no inhibition of apoptosis with the pan caspase inhibitor, ZVAD-FMK. AIF was shown to translocate from the cytosol to the nucleus mediating a caspase independent cell death. Bcl-2 over expressing PC-3 cells, which were resistant to cisplatin induced apoptosis, underwent apoptosis following treatment with all the titanocene compounds. This study demonstrates possible mechanisms by which these novel titanocene compounds can mediate their apoptotic effect in vitro. The fact that they can induce more apoptosis than cisplatin in advanced cancer cell lines would confer an advantage over cisplatin. They represent exciting new agents with future potential for the treatment of advanced prostate cancer.

Antibodies to the E2 protein of GB virus C/hepatitis G virus: low prevalence in Asian countries.

Epidemiological investigations of GB virus C (GBV-C)/hepatitis G virus (HGV), an infectious agent discovered in 1995/1996, are facilitated by a recently developed immunoassay for the detection of antibodies to the viral envelope 2 protein (anti-E2). We used this assay to establish GBV-C/HGV prevalence in seven European, African, and Asian countries. A total of 1579 serum samples from healthy adults lacking prior exposure to known parenteral risk factors was screened. Anti-E2 positivity ranged from 13.6% (Italy) to 7.7% (Mauritius) in the European and African countries investigated. Anti-E2 prevalence was exceedingly low in the Philippines and Sri Lanka. This observation might be attributable to socio-economical and demographic factors.

Evolution of hepatitis G virus infection and antibody response to envelope protein in patients with transfusion-associated non-A, non-B hepatitis.

The clinical significance and course of acute hepatitis G virus (HGV) infection were studied by measuring HGV RNA and antibody to HGV envelope protein E2 (HGV-E2 antibody). A total of 59 patients with transfusion-associated non-A, non-B hepatitis, who were followed-up for more than 1 year, were selected retrospectively. HGV RNA was measured by reverse transcriptase (RT) and nested polymerase chain reaction (PCR) was performed, using primer sets, in the 5'-non-coding region of the HGV genome. HGV-E2 antibody was measured by enzyme-linked immunosorbent assay (ELISA) using recombinant E2 protein. Of the 59 patients, 51 (86%) were infected with hepatitis C virus (HCV) and 12 (20%) were infected with HGV; 11 of the 12 with HGV infection were also infected with HCV. HGV viraemia was cleared during the follow-up period in seven of the 12 patients with HGV infection. All these seven patients seroconverted for HGV-E2 antibody just before or just after the clearance of HGV viraemia. In contrast, all five patients without clearance of HGV viraemia were negative for HGV-E2 antibody (P = 0.0013). Of seven patients with continuous HGV viraemia at 1 year from the onset of acute hepatitis, four with HCV RNA showed chronic elevation of alanine aminotransferase (ALT) but three without HCV RNA did not. The severity of acute hepatitis was similar between patients with both HGV and HCV infections and in those with HCV infection alone. The majority of patients with HGV infection cleared the virus during long-term follow-up. Appearance of HGV-E2 antibody was associated with the clearance of HGV viraemia. An abnormal ALT level was noted to depend on HCV infection but not on HGV infection in both the acute and chronic phases of transfusion-associated hepatitis.

Epidemiological and clinical aspects of hepatitis G virus infection in blood donors and immunocompromised recipients of HGV-contaminated blood.

BACKGROUND AND OBJECTIVES: The infectiousness and clinical relevance of the newly discovered blood-borne Flaviviridae-like agent, termed hepatitis G virus (HGV), are not well understood. MATERIALS AND METHODS: Twenty-three transfusion recipients of two HGV-affected long-term blood donors were studied for HGV genome and antibodies to the putative envelope 2 glycoprotein (anti-E2) of HGV. Nine recipients had nonhematological disorders and 14 suffered from severe hematological diseases and 7 of them received allogeneic bone marrow or blood stem cell transplantation. The molecular epidemiology of the observed HGV infection was studied by direct sequencing of parts of the 5'-noncoding region, NS3, and NS5 region of HGV in the 2 long-term donors and in their 6 recipients who became HGV RNA positive. Additionally, 549 individuals-homologous (n = 254) and autologous blood donors (n = 202), and medical staff (n = 89)--were investigated for the presence of HGV RNA. RESULTS: HGV RNA in serum was found in 15 of the 23 (65%) transfusion recipients with known exposure of HGV-contaminated blood. Seven of the remaining 8 recipients showed only an anti-E2 response, indicating previous HGV infection with spontaneous clearance of the virus. In one recipient neither HGV RNA nor anti-E2 could be detected. Molecular evidence for HGV transmission by the 2 donors was found in 3 of the 6 recipients studied. The alanine aminotransferase levels were not significantly different in the HGV RNA positive and negative recipients, and none of the 23 recipients developed posttransfusion hepatitis. Persistent HGV infection was observed especially in recipients with severe hematological disorders or in those in whom intensive immunosuppressive treatment was necessary. Of the 549 individuals studied, 10 (1.8%) were healthy carriers of HGV RNA. CONCLUSION: The persistence of transfusion-acquired HGV infection is not associated with acute or chronic hepatitis, but may be influenced by the recipient's underlying disease.

Identification of hepatitis G virus particles in human serum by E2-specific monoclonal antibodies generated by DNA immunization.

In order to elucidate the structure and morphology of hepatitis G virus (HGV), a recently isolated flavivirus, we generated a panel of eight monoclonal antibodies (MAbs) against the putative second envelope protein (E2) following DNA immunization. The MAbs were shown to be specific for four different epitopes on recombinant E2. MAb Mc6 was the only antibody able to detect the linear epitope LTGGFYEPL. In addition, Mc6 was able to immunoprecipitate viral particles in human blood samples as detected by reverse transcription-PCR amplification of HGV RNA. This precipitation could be competed by addition of saturating amounts of the linear peptide or abolished by addition of Nonidet P-40. We conclude that, albeit lacking the N-terminal sequence of a functional core protein, HGV builds classical viral particles displaying E2 envelope protein on their outer surfaces.

Distinct prevalence of antibodies to the E2 protein of GB virus C/hepatitis G virus in different parts of the world.

Since the identification of the new human virus, GB virus C (GBV-C)/hepatitis G-virus (HGV), in 1995/1996, reverse transcription polymerase chain reaction remained the sole available diagnostic tool for GBV-C/HGV infection. Recently, a serologic test based on the detection of antibodies to the putative envelope protein 2 (anti-E2) has been introduced. We used this assay for a seroepidemiological survey including 3,314 healthy individuals from different parts of the world, 123 patients from Germany who were suspected to have an increased risk of acquiring GBV-C/HGV infection, 128 multiple organ donors, and 90 GBV-C/HGV RNA positive persons. In European countries, anti-E2 seropositivity ranged from 10.9% (Germany) to 15.3% (Austria). In South Africa (20.3%) and Brazil (19.5%), even higher anti-E2 prevalence rates were recorded. In Asian countries like Bhutan (3.9%), Malaysia (6.3%), and the Philippines (2.7%), anti-E2 positivity was significantly lower. GBV-C/HGV anti-E2 prevalence in potential "risk groups," i.e., patients on hemodialysis and renal transplant recipients, did not vary significantly from anti-E2 seroprevalence in German blood donors. Anti-E2 and GBV-C/HGV RNA were found to be mutually exclusive, confirming the notion that anti-E2 has to be considered as a marker of past infection.

Past and present hepatitis G virus infections in areas where hepatitis C is highly endemic and those where it is not endemic.

We reported previously on an area in Japan where over 30% of the inhabitants were positive for hepatitis C virus (HCV) antibody. In the present study, clinical features of hepatitis G virus (HGV) infection in this area of high endemicity were compared to those in an area where HCV is not endemic. A total of 400 individuals were selected randomly from those who were medically screened for liver disease in 1993; 200 were from the high-endemicity area, and the other 200 were from the no-endemicity area. HGV RNA was measured by reverse transcription and PCR with primers in the 5' noncoding region. Antibody to HGV envelope protein E2 was measured by an enzyme-linked immunosorbent assay. Prevalence of any HGV marker in the high-endemicity area (32%) was significantly (P < 0.0001) higher than that in the no-endemicity area (6%); similar differences, 32% versus 3% (P < 0.0001), had been observed for HCV markers (HCV RNA and HCV antibody). In areas of both high and no endemicity, HCV markers were significantly more prevalent in individuals with any HGV marker than in those without HGV markers, and age-specific prevalence of HGV markers was distributed similarly to that of any HCV marker. Among possible routes of HGV transmission that were analyzed, folk medicine was significant in the high-endemicity area, but blood transfusion was the major route in the no-endemicity area. The rate of accompanying viremia in HGV infection (15%) was significantly lower than that in HCV infection (78%) (P < 0.0001). In conclusion, HGV infection was highly prevalent in the area of high HCV endemicity and was closely associated with HCV infection. HGV seemed to be transmitted via the practice of folk medicine as well as blood transfusion. HGV resulted in a chronic carrier state less frequently than did HCV.

Humoral immune response to the E2 protein of hepatitis G virus is associated with long-term recovery from infection and reveals a high frequency of hepatitis G virus exposure among healthy blood donors.

The second envelope protein (E2) of the hepatitis G virus (HGV) was expressed in Chinese hamster ovary (CHO) cells and showed a molecular weight of approximately 60 to 70 kd, with 15 to 25 kd of the size contributed by N-linked glycosylation. An enzyme-linked immunosorbent assay (ELISA) using HGV-E2 was developed to test for antibodies to this protein (anti-E2) in human sera. High sensitivity was achieved by developing monoclonal antibodies (mAbs) to HGV-E2, which were used as capture antibodies in the ELISA. Our studies revealed that 16% of healthy Spanish blood donors were exposed to HGV, indicating that additional routes of viral transmission besides parenteral exposure might exist. An even higher prevalence of exposure to HGV (52%-73%) was found in several groups at risk of parenteral exposure to infectious agents, i.e., intravenous drug users, transfusion history, hemophiliacs, and hepatitis C virus (HCV)-positive patients. Most anti-E2-positive patients were HGV-RNA-negative and vice versa, indicating an inverse correlation of these two viral markers. A panel of 16 posttransfusion patients followed for up to 16 years revealed that patients who develop an anti-E2 response become HGV-RNA-negative, while patients who do not develop anti-E2 are persistently infected. Immunity to HGV seems to be long-lasting, because circulating antibody to E2 could still be detected 14 years after seroconversion. Sequence comparisons showed that E2 is highly conserved among isolates collected worldwide, indicating that immune escape variants are not common in HGV infections. This reflects on a molecular level why HGV infections usually are cleared spontaneously by the host. However, possible mechanisms of HGV persistence, as found in some patients, remain to be elucidated.