HHV-6A in syncytial giant-cell hepatitis

Striking Cholestatic Giant Cell Hepatitis Resulting in Fulminant Liver Failure After Garcinia Cambogia Use

Garcinia cambogia, a weight control herbal, can cause mild liver toxicity with nonspecific histologic changes. Herein, we reported a case of herbal-induced fulminant cholestatic giant cell hepatitis due to garcinia cambogia use. A 65-year-old woman with breast cancer treated 18 years earlier was admitted for obstructive jaundice for 2 weeks. She started using garcinia cambogia 3 months ago for weight loss. Physical exam showed scleral icterus. Serum studies excluded Wilson's disease, systemic infection including COVID-19 (coronavirus disease 2019), autoimmune hepatitis, and metabolic or toxicologic causes. An urgent liver biopsy showed severe giant cell hepatitis in absence of HSV-1/2, cytomegalovirus, HBsAg and HBcAg (immunostain), and EBV (in situ hybridization). Despite supportive therapy, the patient developed grade 2-3 hepatic encephalopathy and necessitated liver transplant. The explanted liver was markedly atrophy, in which the most striking histologic finding was diffuse distribution of multinucleated giant hepatocytes with syncytial pattern in a background of extensive zone-1 accentuated, geographic, hemorrhagic, confluent hepatocytic necrosis, along with remarkable hepatocytic and canalicular cholestasis. Marked hepatocellular and sinusoidal iron orverload present. The patient recovered uneventfully.

Postinfantile Giant Cell Hepatitis in Native and Allograft Livers: A Multi-Institutional Clinicopathologic Study of 70 Cases

Postinfantile giant cell hepatitis (PIGCH) is a rare hepatitis pattern in adults with variable etiologies and clinical outcomes. We conducted a multi-institutional retrospective study to define the clinicopathologic characteristics of patients with PIGCH. A total of 70 PIGCH cases were identified and reviewed for pathological features, including fibrosis, cholestasis, inflammation, steatosis, necrosis, and apoptosis, as well as the distribution of giant cells and the maximum number of giant cells per high-power field. Demographic and clinical data, including age, sex, laboratory results, etiologies, and follow-up results, were recorded. Among the 70 cases, 40% (28/70) were associated with autoimmune liver diseases, followed by 9 (13%) with unknown etiology, 8 (11%) with viral infection, 5 (7%) with medications, 5 with combined etiologies, and 4 (6%) with malignancies (mostly chronic lymphocytic leukemia). Notably, another 16% were de novo PIGCH in liver allografts, most of which occurred after a rejection event. During follow-up, 26 (37%) patients died of the disease and 44 (63%) were alive. Deceased patients were characterized by older age (mean age, 54.9 vs 45.5 years; P = .02), higher alkaline phosphatase level (mean value, 253.3U/L vs 166.3 U/L; P = .03), higher fibrosis stage (stage 3-4 vs stage 0-2, 57.7% vs 29.6%; P = .03), being more likely to have de novo PIGCH after transplantation (23.1% vs 11.4%; P = .04), and being less likely to have primary autoimmune liver disease etiology (26.9% vs 47.7%; P = .04). These results indicate that PIGCH is a rare pattern of liver injury associated with different etiologies and variable clinical outcomes. Autoimmune liver disease with PIGCH is associated with better survival, whereas de novo PIGCH in allografts is associated with poorer survival. Older age, higher alkaline phosphatase level, and advanced fibrosis are adverse prognostic factors.

Analysis of viral nucleic acids in duodenal biopsies from adult patients with celiac disease

OBJECTIVE

The purpose of this study was to investigate the presence of Adenovirus, Epstein-Barr virus (EBV), HHV-6 and cytomegalovirus (CMV) nucleic acids in the gastrointestinal biopsies from active CD patients.

METHODS

Gastrointestinal biopsies of 40 active CD patients and 40 non-CD patients were collected during the endoscopic investigation of gastrointestinal symptoms.

RESULTS

HHV-6B was found in 62.5% of CD patients and in 65% of non-CD individuals, whereas the prevalence of EBV-positive samples was 20 and 10%, respectively. Nucleic acids from HHV-6A, CMV and adenovirus were not detected in any group.

CONCLUSION

These data suggest that these viruses may not play a role in the pathogenesis of acute CD, but they do not exclude the possibility that viruses can act as a trigger for the onset of celiac disease.

Post-infantile Giant Cell Hepatitis: A Literature Review and Meta-analysis

Post-infantile giant cell hepatitis (PIGCH) is a rare disease entity in adults with a multifactorial etiology and widely variable clinical courses and outcomes. The factors associated with the worse outcomes of this disease entity are still unclear. We identified 68 PIGCH patients by searching PubMed and performed meta-analysis. Among the 68 patients, 32% of the cases were associated with autoimmune disorders, followed by 21% associated with viral infections, 10% with medication, and 7% with malignancy. Twenty-four percent of the patients had more than one etiological factor, and 6% had other uncommon etiologies or an etiology that could not be identified. At the time of this report, 17 patients had died of the disease (poor outcome), and 51 patients remained alive with the disease (good outcome). Compared to the patients with a good outcome, the patients with a poor outcome were characterized by older age, lower levels of platelets and albumin, higher level of total bilirubin, and a diffuse distribution pattern of giant cells in the liver. There were no differences in gender distribution, aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, etiological distribution, or other histological features, including interface hepatitis, necrosis, lobular inflammation, portal inflammation, cholestasis, or fibrosis. Further studies would be needed to better understand the disease mechanisms and unmask any additional etiological factors and targeted therapies.

Insights into the knowledge of complex diseases: Environmental infectious/toxic agents as potential etiopathogenetic factors of systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease secondary to three cardinal pathological features: immune-system alterations, diffuse microangiopathy, and fibrosis involving the skin and internal organs. The etiology of SSc remains quite obscure; it may encompass multiple host genetic and environmental -infectious/chemical-factors. The present review focused on the potential role of environmental agents in the etiopathogenesis of SSc based on epidemiological, clinical, and laboratory investigations previously published in the world literature. Among infectious agents, some viruses that may persist and reactivate in infected individuals, namely human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6), and parvovirus B19 (B19V), and retroviruses have been proposed as potential causative agents of SSc. These viruses share a number of biological activities and consequent pathological alterations, such as endothelial dysfunction and/or fibroblast activation. Moreover, the acute worsening of pre-existing interstitial lung involvement observed in SSc patients with symptomatic SARS-CoV-2 infection might suggest a potential role of this virus in the overall disease outcome. A variety of chemical/occupational agents might be regarded as putative etiological factors of SSc. In this setting, the SSc complicating silica dust exposure represents one of the most promising models of study. Considering the complexity of SSc pathogenesis, none of suggested causative factors may explain the appearance of the whole SSc; it is likely that the disease is the result of a multifactorial and multistep pathogenetic process. A variable combination of potential etiological factors may modulate the appearance of different clinical phenotypes detectable in individual scleroderma patients. The in-deep investigations on the SSc etiopathogenesis may provide useful insights in the broad field of human diseases characterized by diffuse microangiopathy or altered fibrogenesis.

Human Herpesvirus 6 Infection in Pediatric Liver Transplantation: Single-Center Study of Incidence, Outcomes, and Management

BACKGROUND

Distinctions between HHV-6 primary infection in seronegative patients and HHV-6 reactivation in seropositive patients remains largely undescribed in pediatric liver transplant (LT) recipients.

METHODS

We implemented pretransplant serology testing of HHV-6 in a large pediatric hospital and retrospectively assessed the incidence, manifestations and outcomes of HHV-6 infections over a 3-year period.

RESULTS

Among 101 pediatric LT recipients, 96 had pretransplant HHV-6 serologies; 34 (35.4%) were seronegative and 62 (64.6%) seropositive. Posttransplantation, 8/25 (32%) seronegative patients had HHV-6 DNAemia (primary infection) compared to 2/48 (4%) seropositive patients (p=0.002). Compared to seropositive patients, seronegative patients with HHV-6 DNAemia were younger, and had symptoms of fever and/or elevated aminotransferases in association with higher viral loads, in the first month post-transplant. More than 90% of seronegative patients and 77.8% of seropositive patients had HHV-6 detected by PCR in liver biopsy obtained for concerns of allograft rejection, but most had no detectable concomitant DNAemia. Active replication of virus in the liver was confirmed by in situ hybridization in select cases. While HHV-6 infection occurred among patients on prophylaxis doses of antivirals for CMV, HHV-6 DNAemia and presenting symptoms resolved on treatment doses.

CONCLUSIONS

HHV-6 DNA-emia occurred more frequently in seronegative pediatric LT recipients, usually in the early posttransplant period, and was subsequently detected in allograft biopsies. HHV-6 cannot be ruled out as a cause of hepatitis in the absence of allograft tissue testing and specialized virological assays, as HHV-6 may disrupt local allograft immune homeostasis while evading traditional screening methods using blood or plasma. The assessment of pre-transplant HHV-6 serological status may be important for risk stratification and post-transplant management of pediatric LT recipients.

Impact of Human Cytomegalovirus and Human Herpesvirus 6 Infection on the Expression of Factors Associated with Cell Fibrosis and Apoptosis: Clues for Implication in Systemic Sclerosis Development

Systemic sclerosis (SSc) is a severe autoimmune disorder characterized by vasculopathy and multi-organ fibrosis; its etiology and pathogenesis are still largely unknown. Herpesvirus infections, particularly by human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6), have been suggested among triggers of the disease based on virological and immunological observations. However, the direct impact of HCMV and/or HHV-6 infection on cell fibrosis and apoptosis at the cell microenvironment level has not yet been clarified. Thus, this study aimed to investigate the effects of HCMV and HHV-6 infection on the induction of pro-fibrosis or pro-apoptosis conditions in primary human dermal fibroblasts, one of the relevant SSc target cells. The analysis, performed by microarray in in vitro HCMV- or HHV-6-infected vs. uninfected cells, using specific panels for the detection of the main cellular factors associated with fibrosis or apoptosis, showed that both viruses significantly modified the expression of at least 30 pro-fibrotic and 20 pro-apoptotic factors. Notably, several recognized pro-fibrotic factors were highly induced, and most of them were reported to be involved in vivo in the multifactorial and multistep pathogenic process of SSc, thus suggesting a potential role of both HCMV and HHV-6.

Post liver transplant recurrent and de novo viral infections

Survival following liver transplantation has changed dramatically owing to improvement in surgical techniques, peri-operative care and optimal immunosuppressive therapy. Post-Liver transplant (LT) de novo or recurrent viral infection continues to cause major allograft dysfunction, leading to poor graft and patient survival in untreated patients. Availability of highly effective antiviral drugs has significantly improved post-LT survival. Patients transplanted for chronic hepatitis B infection should receive life-long nucleos(t)ide analogues, with or without HBIg for effective viral control. Patients with chronic hepatitis C should be commenced on directly acting antiviral (DAA) drugs prior to transplantation. DAA therapy for post-LT recurrent hepatitis C infection is associated with close to 100% sustained virological response (SVR), irrespective of genotype. De novo chronic Hepatitis E infection is an increasingly recognised cause of allograft dysfunction in LT recipients. Untreated chronic HEV infection of the graft may lead to liver fibrosis and allograft failure. CMV and EBV can reactivate leading to systemic illness following liver transplantation. With COVID-19 pandemic, post-transplant patients are at risk of SARS-Co-V2 infection. Majority of the LT recipients require hospitalization, and the mortality in this population is around 20%. Early recognition of allograft dysfunction and identification of viral aetiology is essential in the management of post-LT de novo or recurrent infections. Optimising immunosuppression is an important step in reducing the severity of allograft damage in the treatment of post-transplant viral infections. Viral clearance or control can be achieved by early initiation of high potency antiviral therapy.

HHV-6-Associated Neurological Disease in Children: Epidemiologic, Clinical, Diagnostic, and Treatment Considerations

Human herpesviruses 6A and 6B, often referred to collectively as human herpesvirus 6, are a pair of beta-herpesviruses known to cause a variety of clinical syndromes in both immunocompetent and immunocompromised individuals. Most humans are infected with human herpesvirus 6B, and many with human herpesvirus 6A. Primary infection typically occurs in early childhood, although large-scale reviews on the topic are limited. Herein, the authors explore the clinical manifestations of human herpesvirus 6-associated disease in both immunocompetent and immunocompromised pediatric patients, the risk factors for development of human herpesvirus 6-associated neurological disease, the risk of autoimmunity associated with development of active or latent infection, the relevance of human herpesvirus 6-specific diagnostic tests, and the medications used to treat human herpesvirus 6. The goal of this review is to improve the current understanding of human herpesvirus 6 in pediatric populations and to examine the most effective diagnostic and therapeutic interventions in this disease state.

HHV-6A Infection and Systemic Sclerosis: Clues of a Possible Association

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, excessive extracellular matrix deposition, and fibrosis of the skin and internal organs. Several infectious agents, including human herpesvirus-6 (HHV-6), have been suggested as possible triggering factors, but a direct association is still missing. We characterized 26 SSc patients for the presence of HHV-6 in tissues and blood, the anti-HHV-6 response, HLA-G plasma levels, and KIR typing. Given the prominent role of endothelial cells (EC) in SSc pathogenesis, along with HHV-6 tropism for EC, we also investigated the expression of pro-fibrosis factors in HHV-6 infected EC. Results showed the presence of HHV-6A in skin biopsies, and an increased virus load was associated with disease severity and poor natural killer (NK) response against the virus, particularly in subjects exhibiting a KIR2 phenotype. HLA-G plasma levels were significantly higher in HHV-6A/B-KIR2 positive SSc patients and in vitro HHV-6A infection-induced pro-fibrosis factors expression in EC, supporting its role in the development of the fibrosing process. Our data suggest an association between virus infection/reactivation and disease, opening the way to future studies to understand the mechanisms by which HHV-6A might contribute to the multifactorial pathogenesis of SSc.

Comparative Analysis of Roseoloviruses in Humans, Pigs, Mice, and Other Species

Viruses of the genus Roseolovirus belong to the subfamily Betaherpesvirinae, family Herpesviridae. Roseoloviruses have been studied in humans, mice and pigs, but they are likely also present in other species. This is the first comparative analysis of roseoloviruses in humans and animals. The human roseoloviruses human herpesvirus 6A (HHV-6A), 6B (HHV-6B), and 7 (HHV-7) are relatively well characterized. In contrast, little is known about the murine roseolovirus (MRV), also known as murine thymic virus (MTV) or murine thymic lymphotrophic virus (MTLV), and the porcine roseolovirus (PRV), initially incorrectly named porcine cytomegalovirus (PCMV). Human roseoloviruses have gained attention because they can cause severe diseases including encephalitis in immunocompromised transplant and AIDS patients and febrile seizures in infants. They have been linked to a number of neurological diseases in the immunocompetent including multiple sclerosis (MS) and Alzheimer's. However, to prove the causality in the latter disease associations is challenging due to the high prevalence of these viruses in the human population. PCMV/PRV has attracted attention because it may be transmitted and pose a risk in xenotransplantation, e.g., the transplantation of pig organs into humans. Most importantly, all roseoloviruses are immunosuppressive, the humoral and cellular immune responses against these viruses are not well studied and vaccines as well as effective antivirals are not available.

Management of giant cell hepatitis associated with chronic lymphocytic leukemia - a case series and review of the literature

Giant cell hepatitis (GCH) is a rare diagnosis in adults that is found in 0.25% of liver biopsies. GCH has been associated with multiple causes including drugs (6-mercaptopurine, methotrexate), toxins, viruses and autoimmune. GCH has been described in few patients with chronic lymphocytic leukemia (CLL). Here we describe three patients diagnosed with GCH thought to be related to underlying CLL and its management. All of our patients were treated with a combination of immunosuppression as well as CLL-directed therapy to address CLL and concomitant liver disease. GCH is a rare manifestation of active CLL and should be ruled out with prompt liver biopsy in patients with CLL with persistent transaminitis without another attributable cause. Prompt treatment of GCH with immunosuppression is required to prevent long-term liver toxicity. If transaminitis does not improve with immunosuppression alone, the addition of CLL directed therapy should be considered in patients who carry this diagnosis to prevent long-term liver toxicity.

Human herpesvirus 6, 7, and 8 in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of HHV-6A, HHV-6B, HHV-7, and HHV-8 in the pre- and post-transplant period. The majority of HHV-6 (A and B) and HHV-7 infections in transplant recipients are asymptomatic; symptomatic disease is reported infrequently across organs. Routine screening for HHV-6 and 7 DNAemia is not recommended in asymptomatic patients, nor is prophylaxis or preemptive therapy. Detection of viral nucleic acid by quantitative PCR in blood or CSF is the preferred method for diagnosis of HHV-6 and HHV-7 infection. The possibility of chromosomally integrated HHV-6 DNA should be considered in individuals with persistently high viral loads. Antiviral therapy should be initiated for HHV-6 encephalitis and should be considered for other manifestations of disease. HHV-8 causes Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease and is also associated with hemophagocytic syndrome and bone marrow failure. HHV-8 screening and monitoring may be indicated to prevent disease. Treatment of HHV-8 related disease centers on reduction of immunosuppression and conversion to sirolimus, while chemotherapy may be needed for unresponsive disease. The role of antiviral therapy for HHV-8 infection has not yet been defined.

Fatal outcome after reactivation of inherited chromosomally integrated HHV-6A (iciHHV-6A) transmitted through liver transplantation

HHV-6A and HHV-6B are found as inherited and chromosomally integrated forms (iciHHV-6A and -6B) into all germinal and somatic cells and vertically transmitted in a Mendelian manner in about 1% of the population. They were occasionally shown to be horizontally transmitted through hematopoietic stem cell transplantation. Here, we present a clinical case of horizontal transmission of iciHHV-6A from donor to recipient through liver transplantation. Molecular analysis performed on three viral genes (7.2 kb) in the recipient and donor samples supports transmission of iciHHV-6A from the graft. Transmission was followed by reactivation, with high viral loads in several compartments. The infection was uncontrollable, leading to severe disease and death, despite antiviral treatments and the absence of resistance mutations. This case highlights the fact that physicians should be aware of the possible horizontal transmission of iciHHV-6 and its consequences in case of reactivation in immunocompromised patients.

Lymphoproliferative Syndromes Associated with Human Herpesvirus-6A and Human Herpesvirus-6B

Human herpesvirus 6A and 6B (HHV-6A and HHV-6B) have been noted since their discovery for their T-lymphotropism. Although it has proven difficult to determine the extent to which HHV-6A and HHV-6B are involved in the pathogenesis of many diseases, evidence suggests that primary infection and reactivation of both viruses may induce or contribute to the progression of several lymphoproliferative disorders, ranging from benign to malignant and including infectious mononucleosis-like illness, drug induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS), and nodular sclerosis Hodgkin's lymphoma. Herein, we discuss the conditions associated with the lymphoproliferative capacity of HHV-6, as well as the potential mechanisms behind them. Continued exploration on this topic may add to our understanding of the interactions between HHV-6 and the immune system and may open the doors to more accurate diagnosis and treatment of certain lymphoproliferative disorders.

Postinfantile Giant Cell Hepatitis with Features of Acute Severe Autoimmune Hepatitis Probably Triggered by Diclofenac in a Patient with Primary Myelofibrosis

Giant cell hepatitis (GCH) is commonly reported in neonatal and infantile liver diseases but rarely in adults where the term postinfantile GCH (PIGCH) is used. PIGCH is associated with many diseases, including drugs toxicity, viruses, and autoimmune liver diseases, with autoimmune hepatitis (AIH) being the most prevalent. We present a case of PIGCH in a 76-year-old female without known history of liver disease who suffered from an acute severe episode of hepatitis. After careful exclusion of other hepatitis causes by imaging, virological, immunological, and microbiological investigations, a diagnosis of acute severe AIH (AS-AIH) was established. The patient was started on corticosteroids but she did not respond and died 3 days later because of advanced acute liver failure. Postmortem liver biopsy showed typical PIGCH lesions. Physicians must keep this catastrophic entity in mind in cases of unexplained acute liver injury as, contrary to our case, prompt rescue therapy with corticosteroids may be life-saving.

HHV-6 in liver transplantation: A literature review

Human herpesvirus 6 (HHV-6A and HHV-6B) can cause primary infection or reactivate from latency in liver transplant recipients, which can result in a variety of clinical syndromes, including fever, hepatitis, encephalitis and higher rates of graft dysfunction as well as indirect effects including increased risks of mortality, CMV disease, hepatitis C progression and greater fibrosis scores. Although HHV-6 infection is currently diagnosed by quantifying viral DNA in plasma or blood, biopsy to demonstrate histopathological effects of HHV-6 remains the gold standard for diagnosis of end-organ disease. HHV-6 reactivation may be restricted to the infected organ with no evidence of active infection in the blood. HHV-6 infections in liver transplant patients are mostly asymptomatic, but clinically significant tissue-invasive infections have been treated successfully with ganciclovir, foscarnet or cidofovir. Inherited chromosomally integrated HHV-6 (ciHHV-6), in either the recipient or the donor organ, may create confusion about systemic HHV-6 infection. Recipients with inherited ciHHV-6 may have an increased risk of opportunistic infection and graft rejection. This article reviews the current scientific data on the clinical effects, risk factors, pathogenesis, diagnosis and treatment of HHV-6 infections in liver transplant recipients.

Chronic and recurrent benign lymphadenopathy without constitutional symptoms associated with human herpesvirus-6B reactivation

Chronic/recurrent behaviour may be encountered in some distinct atypical or malignant lymphoproliferations, while recurrences are not generally observed in reactive/benign lymphadenopathies. We retrospectively analysed a consecutive series of 486 human immunodeficiency virus-negative adults, who underwent lymphadenectomy. Neoplastic and benign/reactive histopathological pictures were documented in 299 (61·5%) and 187 (38·5%) cases, respectively. Of note, seven of the 111 (6·3%) patients with benign lymphadenopathy without well-defined aetiology, showed chronic/recurrent behaviour, without constitutional symptoms. Enlarged lymph nodes were round in shape and hypoechoic, mimicking lymphoma. Reactive follicular hyperplasia and paracortical expansion were observed. Human herpesvirus (HHV)-6B positive staining in follicular dendritic cells (FDCs) was documented in all seven patients. Serological, molecular and immunological examinations suggested HHV-6B reactivation. Among the remaining 104 cases with reactive lymphoid hyperplasia in the absence of well-known aetiology and without recurrences, positivity for HHV-6B on FDCs was found in three cases, whereas in seven further patients, a scanty positivity was documented in rare, scattered cells in inter-follicular regions. Immunohistochemistry for HHV-6A and HHV-6B was invariably negative on 134 lymph nodes, with either benign pictures with known aetiology or malignant lymphoproliferative disorders, tested as further controls. Future studies are warranted to investigate a potential association between HHV-6B reactivation and chronic/recurrent benign lymphadenopathy.

Human herpesvirus-6 and polyomaviruses DNAemia in children and young adult patients after kidney transplantation

Aims: Human herpesvirus-6 (HHV-6) and polyomaviruses (HPyV) establish latency and reactivate in immunocompromised hosts. The prevalence of their infections was investigated in pediatric and young adult kidney transplant recipients. Materials & methods: Blood was obtained from 83 patients. Quantitative real-time polymerase chain reactions were conducted to quantify HHV-6 and HPyV loads; nested PCR and reverse transcriptase-PCR assays were conducted to differentiate HHV-6A from 6B and to evaluate the presence of transcripts. Results: HHV-6 and HPyV DNAemia were detected in 19.3 and 18.1% patients, respectively. No association between HHV-6 and HPyV DNA presence, age of patients and time from transplant was observed. Conclusion: HHV-6 infection in immunosuppression setting was as common as those of HPyVs that are commonly recognized as opportunistic agents.

Increase in Peripheral CD3-CD56brightCD16- Natural Killer Cells in Hashimoto's Thyroiditis Associated with HHV-6 Infection

Hashimoto's thyroiditis (HT) is a very common autoimmune disease of the thyroid. In addition to genetic background, several viruses, including herpesviruses, have been suggested to play a role as possible environmental triggers of disease, but conclusive data are still lacking. Previous results showed that HT patients have an increased cellular immune response directed against the HHV-6 U94 protein and increased NK activity directed against HHV-6 infected thyrocytes.In this study, we characterized the antiviral antibody response and the NK cells activity and subtype in HHV-6 infected HT patients. The results showed that HT subjects have increased prevalence and titer of anti-U94 antibodies and a higher amount of CD3-CD56(bright)CD16(-)NK cell percentages compared to controls. Furthermore, the cell activation of CD3(-)CD56(bright) NK cells in HT patients significantly correlates with TPO and Tg Ab levels.The results suggest that HHV-6 might contribute to HT development, increasing NK cell secretion of inflammatory cytokines that could sustain the persistence of an inflammatory status in HT patients.

Detection of HHV-6-specific mRNA and antigens in PBMCs of individuals with chromosomally integrated HHV-6 (ciHHV-6)

After inheritance of chromosomally integrated HHV-6 (ciHHV-6), viral DNA is found in every nucleated cell. The prevalence of ciHHV-6 is estimated to be 0.2-5% of humans. There are conflicting data on the potential for replication, possibly leading to clinical implications. We analysed peripheral blood mononuclear cells (PBMCs) from individuals with ciHHV-6 proven by fluorescence in situ hybridization (FISH) for HHV-6-specific mRNA (U94, U42, U22) and antigens by means of reverse transcription PCR and an indirect immunoperoxidase staining. U94 transcripts indicative of latent infection were detected in six (54.5%) out of 11 individuals at least once. Transcripts indicative of lytic infection (i.e. U42 and U22) were detected in four (36.4%) out of 11 individuals at least once. HHV-6 antigen was detected in seven (70%) out of 10 individuals at least once. The presence of viral mRNA and proteins supports virus gene expression from ciHHV-6, which may lead to virus replication. Considering the properties of active HHV-6 infection together with obvious replicative activity in individuals with ciHHV-6, pathophysiological effects leading to clinical consequences of chromosomally integrated viral DNA might be considered.

Infections due to human herpesvirus 6 in solid organ transplant recipients

PURPOSE OF REVIEW

This article summarizes the current state of the epidemiology, diagnosis, and management of human herpesvirus 6 (HHV-6) infection after solid organ transplantation.

RECENT FINDINGS

HHV-6 reactivates commonly during the early weeks after solid organ transplantation. However, disease due to HHV-6 is uncommon and is manifested as a febrile illness associated with rash and tissue-invasive manifestations such as encephalitis, hepatitis, pneumonitis, and gastrointestinal disease. HHV-6 has also been indirectly associated with other opportunistic infections such as cytomegalovirus and fungal infections. Molecular tests such as PCR assays are preferred methods for the diagnosis of HHV-6 infection. Recent guideline from the American Society of Transplantation Infectious Disease Community of Practice does not recommend specific antiviral prophylaxis or preemptive therapy for HHV-6 infection. For established disease, intravenous ganciclovir and foscarnet are considered first-line agents.

SUMMARY

Infection due to HHV-6 is a common after transplantation, but clinical disease is rare. Nonetheless, this infection has been indirectly associated with poor allograft and patient survival after transplantation. No specific prevention strategy is recommended, but treatment of established HHV-6 disease consists of antiviral therapy with intravenous ganciclovir and/or foscarnet, and reduction in immunosuppression.

Classification of HHV-6A and HHV-6B as distinct viruses

Shortly after the discovery of human herpesvirus 6 (HHV-6), two distinct variants, HHV-6A and HHV-6B, were identified. In 2012, the International Committee on Taxonomy of Viruses (ICTV) classified HHV-6A and HHV-6B as separate viruses. This review outlines several of the documented epidemiological, biological, and immunological distinctions between HHV-6A and HHV-6B, which support the ICTV classification. The utilization of virus-specific clinical and laboratory assays for distinguishing HHV-6A and HHV-6B is now required for further classification. For clarity in biological and clinical distinctions between HHV-6A and HHV-6B, scientists and physicians are herein urged, where possible, to differentiate carefully between HHV-6A and HHV-6B in all future publications.

Giant cell hepatitis with autoimmune hemolytic anemia in children: proposal for therapeutic approach

BACKGROUND AND OBJECTIVE

Giant cell hepatitis (GCH) with autoimmune hemolytic anemia (AIHA) is a rare, progressive disorder in infants and young children. The disease is aggressive and may lead to liver or multiorgan failure with fatal prognosis. Therapy with anti-CD20 monoclonal antibody, rituximab (Rtx), proved effective. The primary objective of the study was to evaluate therapy for severe GCH with AIHA.

METHODS

We report on 5 cases of severe GCH with AIHA treated in our department between 2006 and 2011.

RESULTS

The median age of the children was 7 months (2-12 months), follow-up lasted 44 months (12-78 months), median (min-max), and the main observed symptoms were jaundice and hepatosplenomegaly. All of the children had positive direct Coombs test and biopsy-proven giant cell transformation of hepatocytes. Liver failure was observed in 3 children. First-line therapy (prednisone, azathioprine) proved ineffective in all but 1 of the patients, who initially responded to the treatment but relapsed after 4 months. The child subsequently developed hemophagocytic lymphohistiocytosis and died 2 months after hemopoietic stem cell transplantation. Four remaining patients finally achieved complete remission after 4 to 6 doses of Rtx.

CONCLUSIONS

We propose Rtx as the treatment of choice for severe GCH with AIHA in the early stages of the disease, provided steroids and azathioprine are ineffective.

Possible role of human herpesvirus 6 as a trigger of autoimmune disease

Human herpesvirus 6 (HHV-6) infection is common and has a worldwide distribution. Recently, HHV-6A and HHV-6B have been reclassified into two distinct species based on different biological features (genetic, antigenic, and cell tropism) and disease associations. A role for HHV-6A/B has been proposed in several autoimmune disorders (AD), including multiple sclerosis (MS), autoimmune connective tissue diseases, and Hashimoto's thyroiditis. The focus of this review is to discuss the above-mentioned AD associated with HHV-6 and the mechanisms proposed for HHV-6A/B-induced autoimmunity. HHV-6A/B could trigger autoimmunity by exposing high amounts of normally sequestered cell antigens, through lysis of infected cells. Another potential trigger is represented by molecular mimicry, with the synthesis of viral proteins that resemble cellular molecules, as a mechanism of immune escape. The virus could also induce aberrant expression of histocompatibility molecules thereby promoting the presentation of autoantigens. CD46-HHV-6A/B interaction is a new attractive mechanism proposed: HHV-6A/B (especially HHV-6A) could participate in neuroinflammation in the context of MS by promoting inflammatory processes through CD46 binding. Although HHV-6A/B has the ability to trigger all the above-mentioned mechanisms, more studies are required to fully elucidate the possible role of HHV-6A/B as a trigger of AD.

Human Herpesvirus 6 and Neuroinflammation

Human herpesvirus (HHV-) 6A and HHV-6B are two distinct β-herpesviruses which have been associated with various neurological diseases, including encephalitis, meningitis, epilepsy, and multiple sclerosis. Although the reactivation of both viruses is recognized as the cause of some neurological complications in conditions of immunosuppression, their involvement in neuroinflammatory diseases in immunocompetent people is still unclear, and the mechanisms involved have not been completely elucidated. Here, we review the available data providing evidence for the capacity of HHV-6A and -6B to infect the central nervous system and to induce proinflammatory responses by infected cells. We discuss the potential role of both viruses in neuroinflammatory pathologies and the mechanisms which could explain virus-induced neuropathogenesis.

Postinfantile giant cell hepatitis: an etiological and prognostic perspective

Giant cell hepatitis is common manifestation in pediatric liver diseases, but quite uncommon in adults, only about 100 cases reported in the English literature in the last two decades. Data for the present review were identified by a structured PubMed/MEDLINE search from 1963 to December 2012, using keywords postinfantile giant cell hepatitis (PIGCH), adult giant cell hepatitis, and syncytial giant cell hepatitis in adults and liver. We report a case of postinfantile giant cell hepatitis along with the review related to the etiology and respective outcome, as the literature in the last 20 years suggests. This condition is probably due to idiosyncratic or cytopathic response of individual to various hepatocytic stimuli. It is purely a histomorphological diagnosis and does not establish the etiology. Autoimmune liver diseases are most common etiology, in around 40% of cases, but various viruses, drugs, posttransplant condition, and other causes also have been reported. Prognosis depends upon the etiology. In this paper, we emphasized various causative factors of PIGCH and their respective outcome in patients affected by them. We also highlighted the possible pathogenesis and histopathological spectrum of this entity on the basis of description given in various studies and our limited experience of few cases.

Calibrated real-time polymerase chain reaction for specific quantitation of HHV-6A and HHV-6B in clinical samples

The recent classification of human herpesvirus 6 (HHV-6) A and B, previously considered as two variants of the same virus, as two distinct herpesvirus species, emphasizes the need to develop and standardize specific methods for their detection and quantitation for clinical use. The development of two highly sensitive calibrated real-time PCR to quantify HHV-6A and -6B variants in clinical specimen is described. Both assays displayed the same wide linear dynamic range from 10(0) to 10(6) copies of viral DNA in a single reaction and sensitivity of one copy/reaction. These systems allow for HHV-6A/B DNA load quantitation in different types of clinical specimens: blood or tissue cells when combined with the CCR5 assay; cell-free samples (plasma or other biological fluids) in combination with the calibrator technology. Due to the absence of cross-amplification and cross-hybridization, these methods detect minute amounts of one viral species even in the presence of a large excess of the other, allowing a specific quantitation of both viruses in the case of mixed infections. The new qPCR methods provide sensitive and specific tool for monitoring HHV-6A/B DNA load in clinical samples, facilitating the study of these viruses in human diseases.

Human herpesviruses 6, 7 and 8 in solid organ transplant recipients

Human herpesviruses (HHV) 6 and 7 are ubiquitous infections that reactivate commonly in transplant recipients. However, clinical diseases due to these viruses are reported only in 1% of solid organ transplant recipients. Fever, rash and bone marrow suppression are the most common manifestations, but symptoms of tissue invasive disease may be observed. Treatment of HHV-6 and HHV-7 disease includes antiviral therapy and cautious reduction in immunosuppression. HHV-8 is an oncogenic gamma-herpesvirus that causes Kaposi's sarcoma, Castleman's disease and primary effusion lymphomas in transplant recipients. Nonmalignant diseases such as bone marrow suppression and multiorgan failure have also been associated with HHV-8. Reduction in immunosuppression is the first line treatment of HHV-8 infection. Other alternatives for treatment, especially for HHV-8 diseases not responsive to immuno-minimization strategies, are surgery and chemotherapy. Sirolimus has been shown to be a beneficial component for the treatment of Kaposi's sarcoma and the role of antivirals for HHV-8 infection is being investigated.

Features of Human Herpesvirus-6A and -6B Entry

Human herpesvirus-6 (HHV-6) is a T lymphotropic herpesvirus belonging to the Betaherpesvirinae subfamily. HHV-6 was long classified into variants A and B (HHV-6A and HHV-6B); however, recently, HHV-6A and HHV-6B were reclassified as different species. The process of herpesvirus entry into target cells is complicated, and in the case of HHV-6A and HHV-6B, the detailed mechanism remains to be elucidated, although both viruses are known to enter cells via endocytosis. In this paper, (1) findings about the cellular receptor and its ligand for HHV-6A and HHV-6B are summarized, and (2) a schematic model of HHV-6A's replication cycle, including its entry, is presented. In addition, (3) reports showing the importance of lipids in both the HHV-6A envelope and target-cell membrane for viral entry are reviewed, and (4) glycoproteins involved in cell fusion are discussed.

Virologic and immunologic evidence supporting an association between HHV-6 and Hashimoto's thyroiditis

Hashimoto's thyroiditis (HT) is the most common of all thyroid diseases and is characterized by abundant lymphocyte infiltrate and thyroid impairment, caused by various cell- and antibody-mediated immune processes. Viral infections have been suggested as possible environmental triggers, but conclusive data are not available. We analyzed the presence and transcriptional state of human herpesvirus 6 (HHV-6) in thyroid fine needle aspirates (FNA) and peripheral blood mononuclear cells (PBMCs) from 34 HT patients and 28 controls, showing that HHV-6 DNA prevalence (82% vs. 10%, p≤0.001) and viral load were significantly increased in FNA from HT patients, and thyrocytes from HT FNA displayed a 100-fold higher HHV-6 DNA load compared to infiltrating lymphocytes. In addition, while HHV-6 was strictly latent in positive samples from controls, a low grade acute infection was detected in HT samples. HHV-6 variant characterization was carried out in 10 HT FNA samples, determining that all specimens harbored HHV-6 Variant A.

The tropism of HHV-6 for thyroid cells was verified by infection of Nthy-ori3-1, a thyroid follicular epithelial cell line, showing that thyrocytes are permissive to HHV-6 replication, which induces de novo expression of HLA class II antigens. Furthermore, HHV-6-infected Nthy-ori3-1 cells become targets for NK-mediated killing, NK cells from HT patients show a significantly more efficient killing of HHV-6 infected thyroid cells than healthy controls, and HT patients have increased T-cell responses to HHV-6 U94 protein, associated to viral latency. These observations suggest a potential role for HHV-6 (possibly variant A) in the development or triggering of HT.

Hashimoto's thyroiditis (HT) is a very common autoimmune disease of the thyroid. In addition to genetic background, several viruses, including herpesviruses, have been suggested to play a role as possible environmental triggers of disease, but conclusive data are still lacking. The anecdotal presence of human herpesvirus 6 (HHV-6) in HT specimens prompted us to study a possible association between HHV-6 and HT. Our analysis of fine needle thyroid aspirates and blood from HT patients and controls shows that HHV-6 prevalence and load are highly increased in HT patients. Furthermore, HT-derived thyrocytes harbor active virus, whereas HHV-6 is strictly latent in the few virus-positive controls. We also report that HHV-6 infects thyroid cells, inducing de novo expression of HLA-II surface antigens. Consequently, thyrocytes might behave as antigen presenting cells. Interestingly, immune cells from HT patients kill HHV-6-infected thyrocytes more efficiently than controls. Also, HT patients, but not controls, have specific T-cell responses to HHV-6 U94 protein. It is difficult to prove etiologic links between viral infections and diseases, especially in the case of a ubiquitous agent such as HHV -6. Nevertheless, our findings indicate that HHV-6 might contribute to HT development, and argue for a pathogenic association between HHV-6 and HT.

Two cases of giant cell hepatitis in HIV-infected patients

Giant cell hepatitis (GCH) has been rarely described in adult HIV patients, and its outcome remain unknown. We report two cases of GCH among 81 HIV patients co-infected with the hepatitis C virus (HCV). Both patients had a sustained virological response, suppression of HCV viral load and HIV viral suppression after highly active antiretroviral therapy. Our findings would suggest that the presence of giant cells does not influence the clinical course of hepatitis.

High intrahepatic HHV-6 virus loads but neither CMV nor EBV are associated with decreased graft survival after diagnosis of graft hepatitis

BACKGROUND & AIMS

In liver transplant recipients with graft hepatitis, the relevance of herpesviruses is not well defined.

METHODS

Viral loads of CMV, EBV, and HHV-6 were determined in blood and liver biopsies of 170 liver transplant recipients with graft hepatitis by quantitative PCR.

RESULTS

HHV-6-, CMV-, and EBV-DNA were detected in 58%, 14%, and 44% of the biopsies, respectively, with coinfections in 34%. High intrahepatic HHV-6 DNA levels (>75th percentile, 11.27 copies/1000 cells) and detection of HHV-6 DNAemia were significantly associated with decreased graft survival after diagnosis of graft hepatitis (p=0.014 and p=0.003, respectively, median follow-up was 23.8 months). Multivariate analysis confirmed high intrahepatic HHV-6 loads as an independent factor associated with reduced graft survival (adjusted hazard ratio 2.61, 95%confidence interval 1.16-5.87). Low concentrations of HHV6 DNA in the liver, indicating latent infection, did not influence graft survival. Neither CMV nor EBV (qualitative detection and high virus loads) nor acute rejection (according to the BANFF score) affected graft survival. However, patients had been treated for CMV reactivations and acute rejections in this retrospective study. High age and high bilirubin levels were the other independent factors associated with reduced graft survival (adjusted hazard ratio 3.56CI 1.52-8.34 and 3.23CI 1.50-6.96, respectively).

CONCLUSIONS

High intrahepatic HHV-6-DNA levels are associated with decreased graft survival in liver transplant recipients with graft hepatitis. The significance of HHV-6 as potential etiology of graft hepatitis needs further evaluation.

Fulminant liver failure in Wilson's disease with histologic features of postinfantile giant cell hepatitis; cytomegalovirus as the trigger for both?

Giant cell hepatitis is a well-known histological feature of several neonatal and infantile liver diseases. In contrast, postinfantile giant cell hepatitis is rarely identified in adult liver biopsies. It has been associated with varying etiologies, mainly viral infections, drug toxicity, and autoimmunity. Here, we report an 18-year-old, previously healthy man with acute liver failure, who showed giant cell hepatitis in a liver biopsy. There was no evidence of viral hepatitis A-E, autoimmunity, and no drug history. Diagnostic work-up revealed Wilson's disease as the underlying disease. As syncytial giant cell formation is thought to be a uniform reaction pattern not related to any specific etiology, copper toxicity in Wilson's disease might cause giant cell formation. In contrast, our patient recalled a recent cytomegalovirus infection, which was confirmed serologically. Therefore, the giant cell formation might also be a fingerprint of an intercurrent cytomegalovirus infection as the common trigger for both giant cell hepatitis and decompensation of Wilson's disease.

Human herpesvirus-6 infections in kidney, liver, lung, and heart transplantation: review

Human herpesvirus-6 (HHV-6), which comprises of HHV-6A and HHV-6B, is a common infection after solid organ transplantation. The rate of HHV-6 reactivation is high, although clinical disease is not common. Only 1% of transplant recipients will develop clinical illness associated with HHV-6 infection, and most are ascribable to HHV-6B. Fever, myelosuppression, and end-organ disease, including hepatitis and encephalitis, have been reported. HHV-6 has also been associated with various indirect effects, including a higher rate of CMV disease, acute and chronic graft rejection, and opportunistic infection such as invasive fungal disease. All-cause mortality is increased in solid organ transplant recipients with HHV-6 infection. HHV-6 is somewhat unique among human viruses because of its ability to integrate into the host chromosome. The clinical significance of chromosomally integrated HHV-6 is not yet defined, although a higher rate of bacterial infection and allograft rejection has been suggested. The diagnosis of HHV-6 is now commonly made using nucleic acid testing for HHV-6 DNA in clinical samples, but this can be difficult to interpret owing to the common nature of asymptomatic viral reactivation. Treatment of HHV-6 is indicated in established end-organ disease such as encephalitis. Foscarnet, ganciclovir, and cidofovir have been used for treatment.

An elderly man with syncytial giant cell hepatitis successfully treated by immunosuppressants

Here, we report an elderly man with acute-on-chronic hepatitis accompanied by massive ascites. He showed elevated serum transaminase and anti-nuclear antibody (ANA) levels. Liver biopsy showed diffuse multinucleated giant hepatocytes with interface hepatitis, and he recovered with administration of azathioprine in addition to corticosteroids. Follow-up liver biopsy after recovery showed improvement of hepatic inflammation and reduction of giant hepatocyte formation. The patient is receiving low-dose corticosteroid maintenance therapy and he has remained healthy for 8 years to date. Active immunosuppressive treatment may be beneficial in patients with adult syncitial giant cell hepatitis (AGCH).

Chromosomally integrated human herpesvirus 6: questions and answers

Chromosomally integrated human herpesvirus 6 (ciHHV-6) is a condition in which the complete HHV-6 genome is integrated into the host germ line genome and is vertically transmitted in a Mendelian manner. The condition is found in less than 1% of controls in the USA and UK, but has been found at a somewhat higher prevalence in transplant recipients and other patient populations in several small studies. HHV-6 levels in whole blood that exceed 5.5 log10 copies/ml are strongly suggestive of ciHHV-6. Monitoring DNA load in plasma and serum is unreliable, both for identifying and for monitoring subjects with ciHHV-6 due to cell lysis and release of cellular DNA. High HHV-6 DNA loads associated with ciHHV-6 can lead to erroneous diagnosis of active infection. Transplant recipients with ciHHV-6 may be at increased risk for bacterial infection and graft rejection. ciHHV-6 can be induced to a state of active viral replication in vitro. It is not known whether ciHHV-6 individuals are put at clinical risk by the use of drugs that have been associated with HHV-6 reactivation in vivo or in vitro. Nonetheless, we urge careful observation when use of such drugs is indicated in individuals known to have ciHHV-6. Little is known about whether individuals with ciHHV-6 develop immune tolerance for viral proteins. Further research is needed to determine the role of ciHHV-6 in disease. Copyright © 2011 John Wiley & Sons, Ltd.

Mucorales-specific T cells emerge in the course of invasive mucormycosis and may be used as a surrogate diagnostic marker in high-risk patients

Mucorales-specific T cells were investigated in 28 hematologic patients during the course of their treatment. Three developed proven invasive mucormycosis (IM), 17 had infections of known origin but other than IM, and 8 never had fever during the period of observation. Mucorales-specific T cells could be detected only in patients with IM, both at diagnosis and throughout the entire course of the IM, but neither before nor for long after resolution of the infection. Such T cells predominantly produced IL-4, IFN-γ, IL-10, and to a lesser extent IL-17 and belonged to either CD4(+) or CD8(+) subsets. The specific T cells that produced IFN-γ were able to directly induce damage to Mucorales hyphae. None of the 25 patients without IM had Mucorales-specific T cells. Specific T cells contribute to human immune responses against fungi of the order Mucorales and could be evaluated as a surrogate diagnostic marker of IM.

Giant cell hepatitis with autoimmune hemolytic anemia in early childhood: long-term outcome in 16 children

OBJECTIVE

To assess the outcome of giant cell hepatitis combined with autoimmune hemolytic anemia in early childhood.

STUDY DESIGN

We report on 16 children with this disease evaluated over a 28-year period.

RESULTS

Children (nine boys; median age, 6 months) presented with jaundice, hepatomegaly, elevated aminotransferases, a positive Coombs test, and diffuse giant-cell transformation of hepatocytes on histology. Treatment with prednisone and azathioprine, plus, in three children, cyclosporine, resulted in complete remission in eight, partial remission in six, and failure in two. Relapses of hepatitis and/or anemia occurred in 11 and 10 children, respectively, requiring prolonged high levels of immunosuppression, and splenectomy or Rituximab, respectively. Treatment was stopped after a mean duration of 6 years, with no relapse, in seven children, with a median follow-up of 14 years. One child is alive 9 years after liver transplantation. Four children died of sepsis or multiple organ failure.

CONCLUSIONS

Giant cell hepatitis combined with autoimmune hemolytic anemia requires rigorous treatment. Immunosuppressive therapy results in remission in most cases. A complete cure can be expected after several years of intensive treatment. Liver transplantation may be associated with prolonged survival.

Detection of HHV-6 in over a thousand samples: new types of infection revealed by an analysis of positive results

BACKGROUND

Clinical manifestations of human herpesvirus-6 (HHV-6) have not been clearly defined, and the role of HHV-6 in human disease remains to be fully elucidated.

OBJECTIVE

To determine the frequency of HHV-6 infections at Rennes Teaching Hospital and to describe all possible symptoms of such infections.

STUDY DESIGN

We systematically analyzed in a retrospective study all the samples between May 2003 and December 2004 from patients with HHV-6 by polymerase chain reaction (PCR). Clinical records of patients with positive HHV-6 PCR were recorded. Diagnosis of HHV-6 infection was accepted if all other possible diagnoses had been eliminated.

RESULTS

Over the study period, 1591 PCRs were performed from various tissues, including blood, cerebrospinal fluid, ascitis and tissue biopsies. Forty-three samples from 25 patients tested positive (3%). We describe three groups of clinical manifestations of HHV-6 infection. The first group consisted of neurological complications (32% of patients), including convulsions, encephalitis and chronic psychiatric disorders in immunocompetent patients. The second group consisted of clinical problems relating to gastrointestinal tract, which was found in 9 of our patients (36%). All of these patients were immunocompromised. Four of them presented colitis, and one of them died one month after liver transplantation because of this colitis. The last group of clinical symptoms was associated with maternal-fetal infection leading to abortion following HHV-6 seroconversion during pregnancy.

CONCLUSION

Three clinical types of HHV-6 infections are described: neurological manifestations including encephalitis in non-immunocompromised patients, digestive problems in immunosuppressed patients and severe maternal-fetal infection.

Hepatic expression of cell proliferation markers and growth factors in giant cell hepatitis: implications for the pathogenetic mechanisms involved

OBJECTIVES

The aim of this study is to determine whether amitotic division or nuclear proliferation is involved in the formation of giant cells (GCs) in giant cell hepatitis (GCH).

PATIENTS AND METHODS

Liver sections from 18 pediatric patients with idiopathic infantile GCH and 12 patients with postinfantile GCH were evaluated for the expression of proliferating cell nuclear antigen (PCNA) and human histone 3 (H3) mRNA, transforming growth factor-alpha (TGF-α), TGF-β1, hepatocyte growth factor (HGF), and epidermal growth factor receptor (EGFR).

RESULTS

Proliferation markers were detected in 1% to 80% in the nuclei of GC and non-GC hepatocytes in 10 of 18 (56%) infantile GCH biopsies and 11 of 12 (92%) postinfantile GCH biopsies, but not in normal liver. The expression of proliferation markers in GCs paralleled that in non-GC hepatocytes (P < 0.05 for both markers). TGF-α and EGFR were detected in both GCs (9/29 and 4/30 patients with infantile or postinfantile GCH, respectively) and non-GC hepatocytes (15/29 and 11/30 patients with infantile or postinfantile GCH, respectively). TGF-β1 and HGF were detected mainly in sinusoidal cells in 20 of 29 and 10 of 30 patients with infantile or postinfantile GCH, respectively; the expression of HGF was positively correlated with PCNA and H3 mRNA in non-GC hepatocytes and with H3 mRNA in GCs (P < 0.01).

CONCLUSIONS

Hepatic expressions of nuclear proliferation markers and growth factors were similar in infantile and postinfantile GCH, nuclear proliferation markers were detected in both GCs and non-GC hepatocytes in a high proportion of patients, and expression of HGF correlated positively with the proliferation markers. These data indicate that nuclear proliferation may contribute to the pathogenesis of GCs in at least a proportion of patients with GCH. A model for the pathogenesis of GCH is proposed.