Human herpes virus-8 and other risk factors for Kaposi's sarcoma in kidney transplant recipients. Groupe Cooperatif de Transplantation d' Ile de France (GCIF)

Visceral Kaposi’s Sarcoma as a Presentation in a Newly Diagnosed HIV-Infected Man: A Case Report

Kaposi’s sarcoma is an angioproliferative malignancy due to human herpesvirus-8 and is associated with immunosuppression. Although most cases are cutaneous and resolve with treatment of the underlying condition, few cases present with organ involvement and have a fulminant course. We present a case of a 24-year-old sexually active man who presented with fulminant visceral Kaposi’s sarcoma, without cutaneous involvement. He presented with anasarca, high fever, hypoalbuminemia, and anemia on day five of antiretroviral therapy (ART). There was clinical improvement after the first dose of liposomal doxorubicin. However, given that he developed refractory pancytopenia, with disease relapse by the third week, he received a second dose of doxorubicin, with no clinical improvement, and the patient died with multi-organ dysfunction on day 22 of presentation. The main treatment is liposomal doxorubicin with ART, and the disease is typically associated with a poor prognosis.

Kaposi's Sarcoma-Associated Herpesvirus (KSHV)-Associated Disease in the AIDS Patient: An Update

In this book chapter, we review the current knowledge of the biology and pathogenesis of Kaposi's sarcomaassociated herpesvirus (KSHV). We describe the lifecycle of KSHV, the cancers associated with this virus, as well as current treatment modalities.

Post-transplant malignancies in pediatric liver transplant recipients: Experience of two centers in Turkey

BACKGROUND/AIMS

A liver transplant is the preferred treatment for patients with end-stage liver disease, as it usually results in longterm survival. However, due to the use of chronic immunosuppressive therapy, which is necessary to prevent rejection, de novo cancer is a major risk after transplantation. The aim of this study was to assess the incidence of post-transplant malignancies in children after liver transplantations.

MATERIALS AND METHODS

The study group consisted of 206 liver transplant recipients, with no history of cancer, including hepatocellular carcinoma, in two liver transplantation centers in Turkey between 1997 and 2015. Data were obtained from patient's data chart.

RESULTS

In the study group, de novo cancer was diagnosed in 13 of the 206 patients. Post-transplant lymphoproliferative disease (PTLD) occurred in seven (53.8%) patients and other malignancies in six of the 13 patients. The types of PTLD were as follows: B-cell origin (n=2), Epstein-Barr virus (EBV)-related (n=2), T-cell origin (n=1), and Hodgkin's lymphoma (n=2). EBV DNA was isolated from seven patients, three of whom developed PTLD. The others developed Kaposi's sarcomas, Burkitt's lymphomas, cutaneous large-cell lymphomas, Hodgkin's lymphomas, and liver sarcomas.

CONCLUSION

After transplantation, immunosuppressive treatment is unavoidable, increasing the risk of malignancies. However, a close follow-up and periodic screening can reduce cancer-related mortality and morbidity.

Seroprevalence of human herpesvirus 8 and its impact on the hemoglobin level in patients of end stage of renal diseases

The incidence of Kaposi's sarcoma (KS) is increasing among renal transplant recipients. Patients with end-stage renal disease (ESRD) are immunocompromised and are candidates for renal transplantation, but HHV8 seroprevalence in ESRD patients has not been well documented. A cross-sectional study of 286 ESRD patients and 281 matched subjects without kidney disease was conducted at the First People's Hospital of Huzhou, Zhejiang province to explore the epidemiologic features of HHV8 among ESRD patients in China. Blood samples were collected and HHV8 antibodies and serologic indices were measured. The seroprevalence of HHV8 was 15.3% for ESRD patients and 8.9% for the comparison group. A significant difference in the geometric mean titer (GMT) of the HHV8 antibodies was detected between ESRD patients and the comparison group (617.1 vs 291.7; P = 0.042). The average level of hemoglobin was 11.56 ± 1.78 g/dL for the ESRD group and 13.73 ± 1.42 g/dL for the comparison group, (P > 0.05). Multiple linear regression revealed a negative association between HHV8 infection and plasma hemoglobin concentration (β = -0.682, P = 0.036). We found a higher HHV8 prevalence and a higher level of HHV8 antibody GMT in ESRD patients than the comparison group, which indicate a high risk of posttransplantation KS.

Structure of the Open Reading Frame 49 Protein Encoded by Kaposi's Sarcoma-Associated Herpesvirus

Herpesviruses alternate between the latent and the lytic life cycle. Switching into the lytic life cycle is important for herpesviral replication and disease pathogenesis. Activation of a transcription factor replication and transcription activator (RTA) has been demonstrated to govern this switch in Kaposi's sarcoma-associated herpesvirus (KSHV). The protein encoded by open reading frame 49 from KSHV (ORF49_KSHV) has been shown to upregulate lytic replication in KSHV by enhancing the activities of the RTA. We have solved the crystal structure of the ORF49_KSHV protein to a resolution of 2.4 Å. The ORF49_KSHV protein has a novel fold consisting of 12 alpha-helices bundled into two pseudodomains. Most notably are distinct charged patches on the protein surface, which are possible protein-protein interaction sites. Homologs of the ORF49_KSHV protein in the gammaherpesvirus subfamily have low sequence similarities. Conserved residues are mainly located in the hydrophobic regions, suggesting that they are more likely to play important structural roles than functional ones. Based on the identification and position of three sulfates binding to the positive areas, we performed some initial protein-DNA binding studies by analyzing the thermal stabilization of the protein in the presence of DNA. The ORF49_KSHV protein is stabilized in a dose-responsive manner by double-stranded oligonucleotides, suggesting actual DNA interaction and binding. Biolayer interferometry studies also demonstrated that the ORF49_KSHV protein binds these oligonucleotides.

IMPORTANCE

Kaposi's sarcoma-associated herpesvirus (KSHV) is a tumorigenic gammaherpesvirus that causes multiple cancers and lymphoproliferative diseases. The virus exists mainly in the quiescent latent life cycle, but when it is reactivated into the lytic life cycle, new viruses are produced and disease symptoms usually manifest. Several KSHV proteins play important roles in this reactivation, but their exact roles are still largely unknown. In this study, we report the crystal structure of the open reading frame 49 protein encoded by KSHV (ORF49_KSHV). Possible regions for protein interaction that could harbor functional importance were found on the surface of the ORF49_KSHV protein. This led to the discovery of novel DNA binding properties of the ORF49_KSHV protein. Evolutionary conserved structural elements with the functional homologs of ORF49_KSHV were also established with the structure.

Incidence, risk factors and outcomes of de novo malignancies post liver transplantation

Liver transplantation (LT) is associated with a 2 to 7 fold higher, age and gender adjusted, risk of de novo malignancy. The overall incidence of de novo malignancy post LT ranges from 2.2% to 26%, and 5 and 10 years incidence rates are estimated at 10% to 14.6% and 20% to 32%, respectively. The main risk factors for de novo malignancy include immunosuppression with impaired immunosurveillance, and a number of patient factors which include; age, latent oncogenic viral infections, tobacco and alcohol use history, and underlying liver disease. The most common cancers after LT are non-melanoma skin cancers, accounting for approximately 37% of de novo malignancies, with a noted increase in the ratio of squamous to basal cell cancers. While these types of skin cancer do not impact patient survival, post-transplant lymphoproliferative disorders and solid organ cancer, accounting for 25% and 48% of malignancies, are associated with increased mortality. Patients developing these types of cancer are diagnosed at more advanced stages, and their cancers behave more aggressively compared with the general population. Patients undergoing LT for primary sclerosing cholangitis (particularly with inflammatory bowel disease) and alcoholic liver disease have high rates of malignancies compared with patients undergoing LT for other indications. These populations are at particular risk for gastrointestinal and aerodigestive cancers respectively. Counseling smoking cessation, skin protection from sun exposure and routine clinical follow-up are the current approach in practice. There are no standardized surveillance protocol, but available data suggests that regimented surveillance strategies are needed and capable of yielding cancer diagnosis at earlier stages with better resulting survival. Evidence-based strategies are needed to guide optimal surveillance and safe minimization of immunosuppression.

HIV-related hematological malignancies: a concise review

HIV (Human Immunodeficiency Virus) and its consequence, AIDS (acquired immunodeficiency syndrome) are responsible for a human tragedy of incalculable proportions. Patients afflicted by it are susceptible due to an early senescence of the immune system to opportunistic infections and malignancies. Since the introduction in 1996 of highly active anti-retroviral therapy (HAART), the landscape of malignancies associated to HIV/AIDS has changed in a significant manner as a direct result of significant improvement in the morbidity, mortality and life expectancy of HIV infected patients. While there has been a significant decrease in developed countries of malignancies such as Kaposi's sarcoma and Primary CNS lymphomas associated to the pre-HAART HIV-related immunodeficiency, hematological malignancies, particularly non-Hodgkin lymphomas continue to be the most common cancer-related cause of death in HIV infected individuals. This concise review of the subject highlights aspects of the natural history of HIV disease as it relates to the cause of malignancies with emphasis in the management and treatment of HIV-related hematological malignancies.

KSHV LANA--the master regulator of KSHV latency

Kaposi's sarcoma associated herpesvirus (KSHV), like other human herpes viruses, establishes a biphasic life cycle referred to as dormant or latent, and productive or lytic phases. The latent phase is characterized by the persistence of viral episomes in a highly ordered chromatin structure and with the expression of a limited number of viral genes. Latency Associated Nuclear Antigen (LANA) is among the most abundantly expressed proteins during latency and is required for various nuclear functions including the recruitment of cellular machineries for viral DNA replication and segregation of the replicated genomes to daughter cells. LANA achieves these functions by recruiting cellular proteins including replication factors, chromatin modifying enzymes and cellular mitotic apparatus assembly. LANA directly binds to the terminal repeat region of the viral genome and associates with nucleosomal proteins to tether to the host chromosome. Binding of LANA to TR recruits the replication machinery, thereby initiating DNA replication within the TR. However, other regions of the viral genome can also initiate replication as determined by Single Molecule Analysis of the Replicated DNA (SMARD) approach. Recent, next generation sequence analysis of the viral transcriptome shows the expression of additional genes during latent phase. Here, we discuss the newly annotated latent genes and the role of major latent proteins in KSHV biology.

Optimized nonclinical safety assessment strategies supporting clinical development of therapeutic monoclonal antibodies targeting inflammatory diseases

An increasing number of immunomodulatory monoclonal antibodies (mAbs) and IgG Fc fusion proteins are either approved or in early-to-late stage clinical trials for the treatment of chronic inflammatory conditions, autoimmune diseases and organ transplant rejection. The exquisite specificity of mAbs, in combination with their multi-functional properties, high potency, long half-life (permitting intermittent dosing and prolonged pharamcological effects), and general lack of off-target toxicity makes them ideal therapeutics. Dosing with mAbs for these severe and debilitating but often non life-threatening diseases is usually prolonged, for several months or years, and not only affects adults, including sensitive populations such as woman of child-bearing potential (WoCBP) and the elderly, but also children. Immunosuppression is usually a therapeutic goal of these mAbs and when administered to patients whose treatment program often involves other immunosuppressive therapies, there is an inherent risk for frank immunosuppression and reduced host defence which when prolonged increases the risk of infection and cancer. In addition when mAbs interact with the immune system they can induce other adverse immune-mediated drug reactions such as infusion reactions, cytokine release syndrome, anaphylaxis, immune-complex-mediated pathology and autoimmunity. An overview of the nonclinical safety assessment and risk mitigation strategies utilized to characterize these immunomodulatory mAbs and Fc fusion proteins to support first-in human (FIH) studies and futher clinical development in inflammatory disease indications is provided. Specific emphasis is placed on the design of studies to qualify animal species for toxicology studies, early studies to investigate safety and define PK/PD relationships, FIH-enabling and chronic toxicology studies, immunotoxicity, developmental, reproductive and juvenile toxicity studies and studies to determine the potential for immunosuppression and reduced host defence against infection and cancer. Nonclinical strategies to facilitate clinical and market entry in the most efficient timeframe are presented.

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.

How I treat HHV8/KSHV-related diseases in posttransplant patients

Posttransplantation human herpesvirus-8 (HHV8)/Kaposi sarcoma herpesvirus (KSHV) primary infection and/or reactivations are associated with uncommon and sometimes fatal, neoplastic, and non-neoplastic diseases. HHV8-related clinical manifestations notably range from Kaposi sarcoma (KS) to either primary effusion lymphoma or multicentric Castleman disease B-cell malignancies, and from polyclonal HHV8-positive plasmacytic lymphoproliferative disorders to bone marrow failure and peripheral cytopenias, associated or not with hemophagocytic syndromes, and to acute hepatitis syndromes. We reviewed the patient series reported in the literature and summarized clinical management aspects, in terms of diagnosis, follow-up, and treatment. We described typical clinical presentations and histopathologic diagnostic features of these diseases, and we discussed the role of HHV8-specific serologic, molecular, and immunologic assays, particularly focusing on recent data from HHV8-specific T-cell monitoring in posttransplantation KS patients. We finally discussed actual therapeutic options, namely, the reduction or discontinuation of immunosuppressive therapy or the switch from calcineurin inhibitors to mTOR inhibitors, as alternatives to antineoplastic chemotherapy, along with the use of antiherpesvirus agents as prophylactic or therapeutic measures, and treatment with rituximab in posttrans-plantation multicentric Castleman disease patients and non-neoplastic HHV8-associated syndromes.

Active lytic infection of human primary tonsillar B cells by KSHV and its noncytolytic control by activated CD4+ T cells

Kaposi sarcoma-associated herpesvirus (KSHV) is a B-lymphotropic virus whose primary site of replication is the oropharynx. KSHV can infect both T and B cells from primary tonsillar explant cultures. However, T cells do not support lytic replication, while B cells spontaneously produce substantial amounts of infectious virus. Here, we provide evidence for a mechanism by which activated T cells may promote or stabilize latency of KSHV infection in B cells. When mixed cultures of B cells and activated T cells were exposed to KSHV, little spontaneous virus production was observed. Removing T cells from the mix or treating the mixed culture with immune suppressants enhanced virus production. Adding back activated T cells to purified infected B cells efficiently suppressed KSHV production, primarily due to CD4(+) T cells. This suppressive activity required T cell activation and direct cell-cell contact, but not prior exposure to KSHV antigen. Suppression was not MHC restricted and did not result in killing of the target cell. We therefore propose that oropharyngeal T cells activated by a variety of stimuli can recognize ligands on infected target B cells, leading to signaling events that prevent spontaneous lytic activation and promote latent infection in this compartment.

Kaposi's sarcoma and mTOR: a crossroad between viral infection neoangiogenesis and immunosuppression

The incidence of Kaposi's sarcoma (KS) among the recipients of solid organ transplants is about 500 times the rate in the general population, suggesting a role for immunosuppression in the development of the disease. The drugs used for the induction and maintenance of immunosuppression and the length of treatment with these agents influence both the incidence and the type of cancer development. The clinical presentation of KS in transplant recipients is often limited to the skin. The risk of death from KS is related to the form and extent of the lesions. The main approach to managing transplant-associated KS is to reduce or even discontinue immunosuppressive therapy; this strategy carries a risk of acute rejection of the graft. KS is a multicentric tumor composed of endothelium-lined vascular spaces and spindle-shaped cells. Its pathogenesis is unclear. Recent evidence suggests that vascular endothelial growth factor (VEGF) is likely to be a growth factor for KS cells: blocking the interaction between VEGF and Flk-1/KDR can abolish VEGF-induced growth of the tumor. Recently, Sirolimus, a drug used in kidney-transplant recipients, has been suggested to reduce KS progression in transplant recipients. This unexpected effect of the drug confirms previous experimental information on KS pathogenesis and may shed light on an array of molecular mechanisms, modulated by Sirolimus, of potential clinical interest in the transplantation scenario.

[Effects of viral infection on transplant recipients]

Viral infection remains an important cause of morbidity and mortality in transplant recipients. The risk of viral infection in these patients depends on several factors, such as the type of organ transplanted, the intensity of immunosuppression, and the recipient's susceptibility. In additional to direct effects, viral infection cause indirect effects, including greater risk of replication of other viruses, graft rejection, opportunistic infections and other specific entities for each type of transplant. These indirect effects result from the immunomodulatory activity of some viruses, such as cytomegalovirus and human herpes virus-6. For the most part, quantitative molecular tests have replaced serologic testing and in vitro culture for diagnosing infection. This approach is particularly prominent for cytomegalovirus, Epstein-Barr virus, hepatitis B virus, and hepatitis C virus. Despite these diagnostic advances, the development of specific antiviral agents and effective antiviral vaccines is limited. Thus, prophylactic strategies are still essential in transplant recipients.

Erythropoietic therapy: Cost efficiency and reimbursement

PURPOSE

The practice of blood conservation is aimed at improving patient outcomes by avoiding allogeneic transfusions via a coordinated multidisciplinary, multipronged approach. The numerous blood conservation techniques and transfusion alternatives now available are described.

SUMMARY

Ongoing concerns exist regarding the availability of the nation's and the world's blood supply. In addition, the number of measures required to ensure blood safety has led to increases in the price of blood and blood products over the past 10-15 years. Moreover, blood transfusion carries inherent risks even under the most favorable circumstances. Investigations have established that injudicious transfusion is associated with development of ventilator-associated pneumonia, nosocomial infection, and organ dysfunction. Because most single blood-conservation techniques reduce blood usage by a mere 1-2 units, a series of integrated conservation approaches are required. These include preoperative autologous donation, use of erythropoietic agents, blood conservation techniques such as acute normovolemic hemodilution, individualized assessment of anemia tolerance, implementation of conservative transfusion thresholds, meticulous surgical techniques, and judicious use of phlebotomy and pharmacologic agents for limiting blood loss. Erythropoietic agents such as epoetin alfa have been used successfully to increase hemoglobin and decrease transfusion requirements, and are appropriate when used in advance of elective surgical procedures. Acquisition costs of erythropoietic stimulating agents versus costs of blood justify economic evaluation by hospitals to make the most cost-effective choice under current economic constraints.

CONCLUSION

Initiating a blood management program requires planning and support from those who are concerned about blood usage reduction and outcomes improvement. Launching a vigorous and ongoing educational program to raise awareness about the risks and hazards associated with blood transfusion is an important step in helping to reshape the medical staffs' attitudes about transfusion and the most cost-effective way to achieve clinical goals.

Kaposi's sarcoma of the gastrointestinal tract: report of two cases and review of the literature

Involvement of Kaposi's sarcoma in the gastrointestinal tract is common in AIDS patients and can also occur in non-AIDS patients. However, the disease is usually asymptomatic and, due to tumor growth primarily in the submucosa, biopsy diagnosis is possible in less than 25%. In the present study, we describe two cases of Kaposi's sarcoma that were first diagnosed in the gastrointestinal tract of a 74-year-old patient who presented to the clinic with nausea and vomiting. On esophagogastroduodenoscopy, a lesion 0.7 cm in size was found. Histology revealed a Kaposi's sarcoma of the stomach with existing HHV8 infection, and there were negative tests for HIV. The second case is a 39-year-old patient with multiple lesions in the stomach and in the small and large intestine. The histology verified multiple Kaposi's sarcomas that were HHV 8-positive. Afterwards, the diagnosis of an HIV infection was made. Primary diagnosis of Kaposi's sarcoma of the gastrointestinal tract in HIV-negative patients is certainly rare and more frequently made in HIV patients. Nevertheless, Kaposi's sarcoma must always be considered in lesions of the gastrointestinal tract or in gastrointestinal bleeding and should lead to further elucidation of the causes.

Rapamycin is efficacious against primary effusion lymphoma (PEL) cell lines in vivo by inhibiting autocrine signaling

The antitumor potency of the mTOR inhibitor rapamycin (sirolimus) is the subject of intense investigations. Primary effusion lymphoma (PEL) appears as an AIDS-defining lymphoma and like Kaposi sarcoma has been linked to Kaposi sarcoma-associated herpesvirus (KSHV). We find that (1) rapamycin is efficacious against PEL in culture and in a murine xenograft model; (2) mTOR, its activator Akt, and its target p70S6 kinase are phosphorylated in PEL; (3) rapamycin inhibits mTOR signaling as determined by S6 phosphorylation; (4) KSHV transcription is unaffected; (5) inhibition of IL-10 signaling correlates with drug sensitivity; and (6) addition of exogenous IL-10 or IL-6 can reverse the rapamycin growth arrest. This validates sirolimus as a new treatment option for PEL.

De novo cancers and post-transplant lymphoproliferative disorder in adult liver transplantation

De novo cancer is one of the most serious complications after organ transplantation. Chronic immunosuppression, viral agents, pretransplant chronic alcohol-induced and other addictive behavior-induced injury are important conditions associated with the development of de novo cancers in solid organ transplants. The aim of the study was to evaluate types and clinical course of de novo cancers in adult liver transplant recipients. Data regarding 502 adult patients who underwent to 554 liver transplantations have been collected. Sex, age at transplantation, immunosuppressive regimen, time from transplantation to diagnosis of cancer, cancer type, surgical and non-surgical treatments and follow-up time have been analyzed as well as acute rejection episodes and viral status. Thirty patients developed 31 de novo cancers. The predominant tumors were carcinoma of the skin, lymphomas and Kaposi's sarcoma. Kaposi's sarcoma and lung cancer were associated with greater mortality. In lymphomas and Kaposi's sarcoma, a high rate of graft involvement was observed. In liver transplant recipients, de novo cancers demand strategies focusing on prophylactic and careful long-term screening protocols. Lymphomas and Kaposi's sarcoma should be ruled out in all patients with clinical manifestations of chronic biliary obstruction.

KSHV after an organ transplant: should we screen?

The incidence of Kaposi sarcoma (KS) related to Kaposi sarcoma-associated herpesvirus (KSHV/HHV-8) after organ transplantation is 500-1000 times greater than in the general population, and its occurrence is associated with immunosuppressive therapy. The reported incidence of posttransplant KS ranges from 0.5% to 5%, depending on the patient's country of origin and the type of organ received, mainly after renal transplantation. Posttransplant KS is caused by two possible mechanisms: KSHV reactivation in patients who were infected before the graft and KSHV contamination from the infected organ's donor to the recipient. KSHV reactivation appears to play a greater role in the risk of KS than incident infections. However, some studies, with findings based not only on serological data but also on molecular tracing of the viral infection, have shown that organ-related transmission of KSHV could be more common than previously thought and associated in some cases with severe KSHV-related disease. Precise estimates of KSHV seroprevalence in the organ donor and recipient populations in different countries are lacking. However, studies have reported seroprevalences among donors and recipients that are similar to those among the general population of the country considered. Many studies have suggested the potential utility of screening of KSHV antibodies among organ donors and recipients. However, to date the results of these studies have argued in favor of KSHV screening, even in low-KSHV infection prevalence countries, not to exclude the graft but to have the KSHV status information in order to have the opportunity to monitor, clinically and biologically, patients at risk for KSHV-related disease development. The detection of KSHV antibodies could be done in the days after the transplantation and the results transmitted to the physicians retrospectively. In conclusion, the question of screening donors and recipients for KSHV, even in low-KSHV infection prevalence countries, is still debated, and prospective studies are needed to evaluate the benefit of pre- and posttransplantation strategies.

Reactivation of Viruses in Solid Organ Transplant Patients Receiving Cytomegalovirus Prophylaxis

A series of substudies of a large international cytomegalovirus (CMV) prophylaxis trial investigated the incidence and clinical relevance of reactivation of human herpesviruses 6, 7, and 8, varicella zoster virus, Epstein-Barr virus, polyomavirus, and adenovirus, and the effect of CMV prophylaxis on clinical and subclinical non-CMV viral infections, in adult solid organ transplant (SOT) patients. Results of the substudy analyses showed that viremia caused by a number of viruses is surprisingly common posttransplantation; most of these infections likely represent reactivation of endogenous latent virus. In addition, although infection or active viral replication was common in this cohort of SOT patients, symptomatic disease due to these viruses was uncommon and the clinical sequelae of viremia were unclear or not apparent. CMV prophylaxis may have modified the natural history of some of these non-CMV viral infections.

Kaposi's sarcoma risk among transplant recipients in the United States (1993–2003)

Kaposi's sarcoma (KS) risk is high in immunosuppressed transplant recipients. KS develops in recipients with pre-existing infection with human herpesvirus 8 (HHV-8), the causative agent for KS, but it can also occur in recipients infected by donors. The relative importance of these sources of infection in recipients in the United States is unknown. We report recipient and donor characteristics associated with KS among transplant recipients in the United States. KS risk, after solid organ transplantation during 1993-2003, was analyzed using data from the Organ Procurement and Tissue Network. Associations were determined using proportional hazards regression. Sixtyfive KS cases were identified among 234,127 transplants (incidence 8.8 per 100,000 person-years). Most cases occurred in the first 2 years after transplantation (incidence 12.5 per 100,000 person-years). KS risk increased steadily with recipient age (p(trend) < 0.001) and was associated with the recipient being male (HR 1.8, 95% CI, 1.0-3.2), Hispanic (2.1, 1.1-3.8) and a non-U.S. citizen (3.9, 1.8-8.6). Mismatch at the HLA-B locus, but not at HLA-A or HLA-DR loci, was associated with heightened risk (HR 3.6, 95%CI 1.1-11 for 1-2 vs. 0 HLA-B mismatches). KS was unrelated to donor characteristics and was not significantly related to use of specific antirejection medications. Our study found that KS incidence was low among transplant recipients in the United States, but it was associated with recipient age, sex and citizenship, perhaps reflecting pre-existing HHV-8 infection. The high KS risk immediately posttransplant and in persons with HLA-B mismatch highlights the role of immunosuppression and/or immune stimulation in KS pathogenesis.

Potent antiviral activity of north-methanocarbathymidine against Kaposi's sarcoma-associated herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV) infection is a prerequisite for the development of Kaposi's sarcoma (KS). Blocking lytic KSHV replication may hinder KS tumorigenesis. Here, we report potent in vitro anti-KSHV activity of 2'-exo-methanocarbathymidine [North-methanocarbathymidine (N-MCT)], a thymidine analog with a pseudosugar ring locked in the northern conformation, which has previously been shown to block the replication of herpes simplex virus types 1 and 2. N-MCT inhibited KSHV virion production in lytically induced KSHV-infected BCBL-1 cells with a substantially lower 50% inhibitory concentration (IC50) than those of cidofovir (CDV) and ganciclovir (GCV) (IC50, mean +/- standard deviation: 0.08 +/- 0.03, 0.42 +/- 0.07, and 0.96 +/- 0.49 microM for N-MCT, CDV, and GCV, respectively). The reduction in KSHV virion production was accompanied by a corresponding decrease in KSHV DNA levels in the N-MCT-treated BCBL-1 cells, indicating that the compound blocked lytic KSHV DNA replication. A time- and dose-dependent accumulation of N-MCT-triphosphate (TP) was demonstrated in lytically induced BCBL-1 cells, while uninfected cells showed virtually no accumulation. The levels of N-MCT-TP were significantly decreased in the presence of 5'-ethynylthymidine, a potent inhibitor of herpesvirus thymidine kinase, resulting in the abrogation of anti-KSHV activity of N-MCT. N-MCT-TP more effectively blocked in vitro DNA synthesis by KSHV DNA polymerase with an IC50 of 6.24 +/- 0.08 microM (mean +/- standard deviation) compared to CDV-diphosphate (14.70 +/-2.47 microM) or GCV-TP (24.59 +/- 5.60 microM). Taken together, N-MCT is a highly potent and target-specific anti-KSHV agent which inhibits lytic KSHV DNA synthesis through its triphosphate metabolite produced in KSHV-infected cells expressing a virally encoded thymidine kinase.

Chemical library screen for novel inhibitors of Kaposi's sarcoma-associated herpesvirus processive DNA synthesis

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma and certain lymphoproliferative disorders. The role of KSHV lytic replication has been implicated in the tumor pathogenesis. A highly specific molecular complex formed by the KSHV DNA polymerase (POL8) and processivity factor (PF8) is indispensable for lytic viral DNA synthesis and may serve as an excellent molecular anti-KSHV target. The majority of conventional nucleoside-based anti-herpetic DNA synthesis inhibitors require intracellular phosphorylation/activation before they can exert inhibitory activity as competitive substrates for viral DNA polymerases. Novel and more potent inhibitors of KSHV DNA synthesis may be discovered through POL8/PF8-targeted high throughput screening (HTS) of small molecule chemical libraries. We developed a microplate-based KSHV POL8/PF8-mediated DNA synthesis inhibition assay suitable for HTS and screened the NCI Diversity Set that comprised 1992 synthetic compounds. Twenty-eight compounds exhibited greater than 50% inhibition. The inhibitory activity was confirmed for 25 of the 26 hit compounds available for further testing, with the 50% inhibitory concentrations ranging from 0.12+/-0.07 microM (mean+/-S.D.) to 10.83+/-4.19 microM. Eighteen of the confirmed active compounds efficiently blocked KSHV processive DNA synthesis in vitro. One of the hit compounds, NSC 373989, a pyrimidoquinoline analog, was shown to dose-dependently reduce the levels of KSHV virion production and KSHV DNA in lytically induced KSHV-infected BCBL-1 cells, suggesting that the compound blocked lytic KSHV DNA synthesis. HTS for KSHV POL8/PF8 inhibitors is feasible and may lead to discovery of novel non-nucleoside KSHV DNA synthesis inhibitors.

Maladie de Kaposi et transplantation d’organes : 22 cas

BACKGROUND

The discovery of the Human Herpes virus 8 (HHV8) improved our knowledge of the pathogenesis of Kaposi's sarcoma. After organ transplantation, Kaposi's sarcoma exhibits distinctive features compared with other forms of the disease.

PATIENTS AND METHODS

We report 22 cases of post-transplant Kaposi's sarcoma (12 kidneys, 2 kidney-pancreas, 6 livers and 2 hearts). The aim of this retrospective study was to analyze clinical and virological characteristics in these transplant patients and to specify the frequency of HHV8 seroconversions in this population.

RESULTS

Twenty-one patients showed cutaneous lesions and 9 had visceral involvement. HHV8 serology was positive in 16/20 patients at transplantation and in 21/22 cases at the time of Kaposi's sarcoma diagnosis. Most cases corresponded to viral reactivations whereas seroconversions occurred in 2 cases and may have been linked to viral transmission by the graft. Treatment led to recovery in 68p. 100 of the cases. Two heart-transplant patients died from their disease. We included in our series two cases of re-transplanted patients without recurrence of Kaposi's sarcoma and one case of familial Kaposi's sarcoma.

DISCUSSION

Seroconversions after transplantation emphasize the interest of systematic screening of HHV8 serology in transplant recipients and their donors.

Linking KSHV to human cancer

Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), has been linked to several malignancies in humans. KSHV is the etiologic agent associated with the development of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). KSHV is a double-stranded DNA virus that has been classified as a gammaherpesvirus. Here, we review the association of KSHV with human cancer, viral genes that may potentially be involved in the neoplastic process, and current therapies used to treat KS, PEL, and MCD.

Kaposi's sarcoma-associated herpesvirus: clinical, diagnostic, and epidemiological aspects

Kaposi's sarcoma-associated herpesvirus (KSHI) is one of the few viruses proven to be associated with tumorigenesis in humans. Its causal association with all clinical and epidemiological variants of Kaposi's sarcoma (KS) is well established. KSHV is also involved in the pathogenesis of primary effusion lymphoma (PEL) and a subset of multicentric Castleman's disease (MCD). Possible associations of KSHV with other clinical settings have been extensively examined. The findings from several of these studies are contradictory and are yet to be resolved. Concentrated effort over the last decade, since the initial discovery of KSHV, led to the development of several experimental systems that resulted in a better comprehension of the biological characteristics of KSHV and set the stage for the understanding of mechainisms by which diseases are induced by the virus. The development of molecular, histological, and serological tools for KSHV diagnosis allowed researchers to track the transmission and to study the epidemiology of KSHV. These assays have been applied, in particular in ambiguous cases, in order to confirm clinically and pathologically based diagnoses. Here, we review the advances in the clinical, experimental, diagnostic, and epidemiological research of KSHV.

Correlates of Human Herpesvirus-8 DNA detection among adults in Italy without Kaposi sarcoma

BACKGROUND

The presence of Human Herpesvirus-8 (HHV8) DNA is predictive of Kaposi sarcoma (KS) among patients with HIV-associated or iatrogenic immunosuppression. However, correlates of HHV8-DNA detection in the general population remain undefined.

METHODS

We assessed correlates of HHV8-DNA detection among Italian adults without KS who had antibodies against HHV8-latent nuclear antigen by immunofluorescence assay. HHV8-K6 DNA sequences were detected in peripheral blood mononuclear cells using TaqMan PCR.

RESULTS

Of the 158 subjects 26 (16.5%) had detectable HHV8-DNA [median copies/million cells, 53; (13-2128)]. Adjusted for age, sex, and laboratory, HHV8-DNA was detected more frequently in participants with >7 total residents in the childhood home [OR = 3.7 (1.5-9.1)], >2 younger siblings [OR = 2.6 (1.1-6.5)], and current cardiovascular [OR = 3.6 (1.3-9.7)] or renal [OR = 3.1 (1.2-8.0)] disease. Excluding the participants using immune modulating drugs, HHV8-DNA was more frequent among those with low red blood cells (RBC) [<4.5 10(6)/microl; OR = 5.3 (1.7-16.2)], slightly elevated mean corpuscular volume [>92 microm3/red cell; OR = 2.8 (1.0-7.8)], and mild thrombocytopenia [<151 K/microl; OR = 5.6 (1.9-16.3)].

CONCLUSIONS

Presence of HHV8-DNA in elderly Italians is associated with childhood crowding, low RBCs, and platelets, perhaps indicating roles for early infection and chronic inflammation. These risk factors are the first to be reported for non-immunosuppressed HHV8-seropositive adults.

Aspects épidémiologiques de l'herpèsvirus humain 8 (HHV-8) et du sarcome de Kaposi

HHV-8 belongs to the herpesviridae family, to the gammaherpesvirinae subfamily, and to the rhadinovirus genus. Whereas several viral homologues exist in non human primates, HHV-8 is the only rhadinovirus known in human. HHV-8 is mainly the etiological agent of the four clinico-epidemiological forms of Kaposi's sarcoma (classic, endemic, post-transplant, and epidemic/HIV associated). HHV-8 is not an ubiquitous virus. It is mainly endemic in areas of high endemicity for classic or endemic Kaposi's sarcoma including the Mediterranean area and most of East and Central Africa. Its prevalence varies in the adult population, from less than 5% in the USA and Northern Europe to more than 50% in some regions of the African continent and around 10 to 20% in Italy and Greece. One can estimate that several hundred million people are HHV-8 infected worldwide with at least 150 million on the African continent. Modes of infection seem different in low and highly endemic areas. In low endemic areas, HHV-8 is mainly present in the male homosexual population, where this herpesvirus is transmitted during sexual contacts. In contrast, in highly endemic areas, as Central Africa, HHV-8 transmission occurs mainly from mother to child and between siblings. Heterosexual transmission remains low as well as transmission through blood products. Saliva seems to play a major role in the viral transmission, and may be a reservoir for HHV-8.

Human herpes virus-8 serology and DNA analysis in recipients of renal allografts showing Kaposi's sarcoma and their respective donors

Kaposi's sarcoma (KS) developed among 11 of 416 renal allograft recipients transplanted between 1985 and 2000. Only 3 among 364 Caucasian recipients developed KS, while it affected 8 of 52 Black patients, all of whom had been born in African countries (P <.001). All patients had their immunosuppression reduced; two also received daunorubicin and one received electrotherapy. Three patients developed accelerated renal allograft dysfunction, probably due to the reduced immunosuppression. Remission of KS was observed in seven patients, while lesions stabilized or improved partially in the other four. After resuming dialysis 2 of 11 patients died; both were in KS remission. Human herpes virus-8 (HHV-8) serology and DNA analysis was evaluated in sera obtained from seven donors: all were negative. Conversely, among eight sera collected pretransplant from the nine living recipients, HHV-8 IgG was detected in six and DNA was present in one. HHV-8 IgG was expressed in all patients (9/9) at some point posttransplant; DNA was detected in three patients. Therefore, the robust ethnic predisposition to KS was associated with a high pretransplant prevalence of HHV-8 among African recipients. Although some seroconversions were detected posttransplant, there was no evidence for donor-to-recipient transmission.

Treatment of refractory Wegener's granulomatosis with antithymocyte globulin (ATG): an open study in 15 patients

BACKGROUND

A subset of patients with Wegener's granulomatosis does not respond sufficiently to cyclophosphamide and glucocorticosteroids or suffers of intolerable side effects. Anecdotal data suggest that antithymocyte globulin (ATG) may be a treatment option for these patients. We now describe 15 patients treated with ATG for refractory Wegener's granulomatosis.

METHODS

Fifteen patients with histologically proven active refractory Wegener's granulomatosis (seven unresponsive to cyclophosphamide, eight intolerant) were treated with ATG by a protocol (SOLUTION protocol) designed by the European Vasculitis Study (EUVAS) Group.

RESULTS

Before ATG administration, patients had received a mean of 5.2 (range 2 to 7) different therapeutic approaches including glucocorticosteroids and cyclophosphamide in all and experimental therapies in six, without control of disease activity [2.8 (range 1 to 7) relapses during a disease duration of 63.2 (range 18 to 180) months]. Thirteen of 15 patients showed a favorable response to ATG with partial (N= 9) or complete (N= 4) remission. During a follow-up of 21.8 (range 6 to 68) months, seven patients relapsed after a mean of 8.4 (range 2 to 24) months (five minor and two major relapses). Six patients are free of relapse for 22.3 (range 7 to 64) months. Two patients died, 1 and 3 days following the first dose of ATG, due to pulmonary hemorrhage and infection (one each). Although further immunosuppressive treatment was required in all surviving patients, a less intensive regimen could be applied in 12. Beside fever and chills associated with the first gift of ATG, ATG was well tolerated, with infections being observed in five cases and serum sickness in two.

CONCLUSION

Anti-T-cell-directed treatment with ATG may be a therapeutic option for severe refractory Wegener's granulomatosis if simultaneous infections and fluid overload have been ruled out. In patients with alveolar hemorrhage, ATG should only be used under special caution.

Comparative evaluation of three serological methods for detection of human herpesvirus 8-specific antibodies in Canadian allogeneic stem cell transplant recipients

Human herpesvirus 8 (HHV-8) has been associated with all types of Kaposi's sarcoma (KS), including posttransplantation KS. However, little is known regarding HHV-8 infections in hematopoietic stem cell transplant (SCT) recipients. In this study, we used a variety of serological assays, including in-house-developed enzyme immunoassays (EIAs) utilizing synthetic peptides corresponding to lytic viral antigens (ORFs 65 and K8.1) and a commercial EIA kit based on a whole virus lysate (Advanced Biotechnologies Inc.), as well as latent- and lytyc-antigen-based immunofluorescence assays (IFAs) to determine the seroprevalence of HHV-8 in 42 allogeneic SCT recipients from Canada. Using the two peptide-based EIA methods as for screening, HHV-8-specific antibodies were detected in five (12%) patients between days 21 and 91, although only one (2%) subject was positive for HHV-8-specific antibodies before transplantation. All positive results from these five patients were confirmed by at least one of the IFAs, with an additional patient showing seropositivity before transplantation. However, the commercial EIA was negative at all time points (days -7, 21, and 91) in those five patients. The episodes of seroconversion or reactivation were not associated with sustained viremia, since HHV-8 DNA was not detected by real-time PCR in the corresponding leukocytes and plasma of the seropositive patients. No clinical or laboratory abnormalities were clearly associated with HHV-8 seropositivity. This study confirms the utility of simple peptide-based EIA methods to assess the presence of HHV-8-specific antibodies in immunocompromised patients and emphasizes the need of conducting prospective studies to determine the source of HHV-8 infection in SCT recipients.

Human herpesvirus 8: an update

The discovery of human herpesvirus 8 (HHV-8) has opened a new field in the biology and in the clinical definition of HHV-8-associated diseases. Various aspects of epidemiology, laboratory diagnosis and treatment of HHV-8 infection are still controversial. This review will summarise the most recent findings on the modalities of viral transmission in geographic areas where the virus is endemic as compared with those where the infection is sporadic. The studies on the interactions between HHV-8 and Epstein-Barr virus in the promotion of tumorigenesis will be then emphasised. This review will finally address the problems still open in the laboratory diagnosis and in the definition of antiviral drug susceptibility of HHV-8. Solving satisfactorily these issues will be necessary to better understand the epidemiology of HHV-8 infection, to reduce the risk of viral transmission, the progression of infected hosts to HHV-8-related malignancies and to achieve more active treatment options for these clinical conditions.

Cancer after kidney transplantation in the United States

Previous reports of cancer after kidney transplantation have been limited by small numbers of patients in single-center studies and incomplete ascertainment of cases in large registries. We examined rates of malignancies among first-time recipients of deceased or living donor kidney transplantations in 1995-2001 (n = 35 765) using Medicare billing claims. For most common tumors, e.g. colon, lung, prostate, stomach, esophagus, pancreas, ovary and breast, cancer rates were roughly twofold higher after kidney transplantation compared with the general population. Melanoma, leukemia, hepatobiliary tumors, cervical and vulvovaginal tumors were each approximately fivefold more common. Testicular and bladder cancers were increased approximately threefold, while kidney cancer was approximately 15-fold more common. Kaposi's sarcoma, non-Hodgkin's lymphomas, and nonmelanoma skin cancers were more than 20-fold increased than in the general population. Compared with patients on the waiting list, several tumors were more common after transplantation (p < 0.01): nonmelanoma skin cancers (2.6-fold), melanoma (2.2-fold), Kaposi's sarcoma (9.0-fold), non-Hodgkin's lymphoma (3.3-fold), cancer of the mouth (2.2-fold), and cancer of the kidney (39% higher). The rates for most malignancies are higher after kidney transplantation compared with the general population. Cancer should continue to be a major focus of prevention in kidney transplantation.

Transmission and disease association of Kaposi's sarcoma-associated herpesvirus: recent developments

PURPOSE OF REVIEW

Kaposi's sarcoma-associated herpesvirus or human herpesvirus 8, common in sub-Saharan Africa and around the Mediterranean Sea but rare in most other countries, is known to be transmitted in childhood within families in endemic regions, and through sexual contacts among high-risk groups in Western countries. Nevertheless recent developments on other modes of transmission of the virus have been made during the last years and are summarized in this review. Furthermore, recent published disease associations are discussed.

RECENT FINDINGS

The last year has seen research addressing the question of parenteral transmission, sexual transmission through heterosexual contact, transmission of Kaposi's sarcoma-associated herpesvirus-infected cells from organ donors to recipient, as well as the first suggestion that host genetic factors may facilitate infection in childhood. Additional clinical manifestations of infection with the virus such as primary pulmonary hypertension and germinotropic lymphoproliferative disorder have been identified.

SUMMARY

Evidence of Kaposi's sarcoma-associated herpesvirus transmission other than between homosexual adults and during childhood - namely transmission through heterosexual contact or injection drug use - is growing although these issues are still incompletely analysed and far away from being fully understood. Despite our increasing knowledge on transmission and disease associations of the virus, implications on the clinical management of associated diseases and public health have to be further evaluated in the coming years.

Emerging Infectious Threats to the Blood Supply

During the past 15 years, it has become clear that new agents and new strains of existing agents continue to emerge worldwide as protagonists of infectious disease. These emerging agents pose threats not only to the general human population but also to recipients of blood transfusions. Indeed, the modern era of blood safety perhaps began with the recognition of HIV as an emerging agent transmissible by blood transfusion. Today, emerging infectious agents that pose a threat to the blood supply are not limited to viruses, but include bacterial, protozoan, and prion agents. Preventing the transmission of these new agents by blood transfusion is often problematic, as the available tools may be inadequate. It is certain, however, that new agents will continue to emerge as threats to blood safety and these agents are likely to require novel approaches to prevent their transmission.