Prevalence, incidence and correlates of HHV-8/KSHV infection and Kaposi's sarcoma in renal and liver transplant recipients

HHV-8-associated diseases in transplantation: A case report and narrative review focused on diagnosis and prevention

BACKGROUND

Human herpes virus 8 (HHV-8) or Kaposi sarcoma herpesvirus (KSHV) is an opportunistic oncovirus that causes multiple pathologic entities.

METHODS

We present a case of fatal HHV-8-associated multisystem illness with disseminated Kaposi sarcoma and HHV8-associated lymphoproliferative disorder with systemic inflammation. We conducted a narrative review of the literature on HHV-8 in transplantation with a goal of illuminating the spectrum of HHV-8-associated diseases in this vulnerable population, modes of disease transmission, and the potential role for donor and recipient screening.

RESULTS

HHV-8-associated KS, primary effusion lymphoma (PEL), multicentric Castleman disease (MCD), and KSHV inflammatory cytokine disorder (KICS) may affect transplant recipients; with the exception of KS, these conditions are rare but carry high morbidity and mortality.

CONCLUSION

HHV-8-associated diseases have diverse and protean manifestations in transplant recipients, with potentially fatal outcomes. HHV-8 seroprevalence among organ donors and the magnitude of risk for donor-derived HHV-8 infection or clinically significant disease remain unknown and require further study.

Infiltrating Kaposi sarcoma presenting as acute kidney injury: An unexpected consequence of deliberate hepatitis C-positive organ transplantation

Kaposi sarcoma (KS) following kidney transplantation can result from recipient reactivation of latent human herpesvirus 8 (HHV-8) infection or activation of donor-acquired HHV-8 infection. Post-transplant KS typically manifests with cutaneous pathology, but rare cases of renal allograft involvement have been reported. We describe two cases of donor-derived HHV-8 infection in two hepatitis C (HCV) viremia-negative transplant recipients who each received a kidney from a donor with HCV viremia. One recipient did not develop KS while the other presented with acute kidney injury caused by extensive KS infiltration of the renal parenchyma and metastatic disease. This report reviews the literature for cases of KS involving the renal allograft and highlights an unexpected consequence of deliberate HCV-positive organ transplantation.

Evidence for altered host genetic factors in KSHV infection and KSHV-related disease development

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS), the most common AIDS-related malignancy. It also causes other rare, but certainly underreported, KSHV-associated pathologies, namely primary effusion lymphoma, multicentric Castleman disease and KSHV inflammatory cytokine syndrome. Epidemiology and pathogenicity studies point to the potential for host genetic predisposition to KSHV infection and/or the subsequent development of KSHV-associated pathologies partly explaining the peculiar geographic and population-specific incidence of KSHV and associated pathologies and discrepancies in KSHV exposure and infection and KSHV infection and disease development. This review consolidates the current knowledge of host genetic factors involved in the KSHV-driven pathogenesis. Studies reviewed here indicate a plausible connection between KSHV susceptibility and host genetic factors that affect either viral access to host cells via entry mechanisms or host innate immunity to viral infection. Subsequent to infection, KSHV-associated pathogenesis, reviewed here primarily in the context of KS, is likely influenced by an orchestrated concert of innate immune system interactions, downstream inflammatory pathways and oncogenic mechanisms. The association studies reviewed here point to interesting candidate genes that may prove important in achieving a more nuanced understanding of the pathogenesis and therapeutic targeting of KSHV and associated diseases. Recent studies on host genetic factors suggest numerous candidate genes strongly associated with KSHV infection or subsequent disease development, particularly innate immune system mediators. Taken together, these contribute toward our understanding of the geographic prevalence and population susceptibility to KSHV and KSHV-associated diseases.

Kaposi's Sarcoma-Associated Herpesvirus Infection Induces the Expression of Neuroendocrine Genes in Endothelial Cells

Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with endothelial Kaposi's sarcoma (KS) in immunocompromised individuals. KS lesion cells exhibit many similarities to neuroendocrine (NE) cancers, such as highly vascular and red/purple tumor lesions, spindle-shaped cells, an insignificant role for classic oncogenes in tumor development, the release of bioactive amines, and indolent growth of the tumors. However, the mechanistic basis for the similarity of KS lesion endothelial cells to neuroendocrine tumors remains unknown. Next-generation sequencing and bioinformatics analysis in the present study demonstrate that endothelial cells latently infected with KSHV express several neuronal and NE genes. De novo infection of primary dermal endothelial cells with live and UV-inactivated KSHV demonstrated that viral gene expression is responsible for the upregulation of five selected NE genes (adrenomedullin 2 [ADM2], histamine receptor H1 [HRH1], neuron-specific enolase [NSE] [ENO2], neuronal protein gene product 9.5 [PGP9.5], and somatostatin receptor 1 [SSTR1]). Immunofluorescence and immunohistochemistry examinations demonstrated the robust expression of the NE genes HRH1 and NSE/ENO2 in KSHV-infected KS tissue samples and KS visceral tissue microarrays. Further analysis demonstrated that KSHV latent open reading frame K12 (ORFK12) gene (kaposin A)-mediated decreased host REST/NRSF (RE1-silencing transcription factor/neuron-restrictive silencer factor) protein, a neuronal gene transcription repressor protein, is responsible for NE gene expression in infected endothelial cells. The NE gene expression observed in KSHV-infected cells was recapitulated in uninfected endothelial cells by the exogenous expression of ORFK12 and by the treatment of cells with the REST inhibitor X5050. When the neuroactive ligand-activating receptor HRH1 and inhibitory SSTR1 were knocked out by CRISPR, HRH1 knockout (KO) significantly inhibited cell proliferation, while SSTR1 KO induced cell proliferation, thus suggesting that HRH1 and SSTR1 probably counteract each other in regulating KSHV-infected endothelial cell proliferation. These results demonstrate that the similarity of KS lesion cells to neuroendocrine tumors is probably a result of KSHV infection-induced transformation of nonneuronal endothelial cells into cells with neuroendocrine features. These studies suggest a potential role of neuroendocrine pathway genes in the pathobiological characteristics of KSHV-infected endothelial cells, including a potential mechanism of escape from the host immune system by the expression of immunologically privileged neuronal-site NE genes, and NE genes could potentially serve as markers for KSHV-infected KS lesion endothelial cells as well as novel therapeutic targets to control KS lesions.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) manipulates several cellular pathways for its survival advantage during its latency in the infected human host. Here, we demonstrate that KSHV infection upregulates the expression of genes related to neuronal and neuroendocrine (NE) functions that are characteristic of NE tumors, both in vitro and in KS patient tissues and the heterogeneity of neuroendocrine receptors having opposing roles in KSHV-infected cell proliferation. Induction of NE genes by KSHV could also provide a potential survival advantage, as the expression of proteins at immunologically privileged sites such as neurons on endothelial cells may be an avenue to escape host immune surveillance functions. The NE gene products identified here could serve as markers for KSHV-infected cells and could potentially serve as therapeutic targets to combat KSHV-associated KS.

Kaposi's sarcoma-associated herpesvirus seropositivity is associated with parasite infections in Ugandan fishing communities on Lake Victoria islands

We investigated the impact of helminths and malaria infection on Kaposi's sarcoma associated herpesvirus (KSHV) seropositivity, using samples and data collected from a cluster-randomised trial of intensive versus standard anthelminthic treatment. The trial was carried out in 2012 to 2016 among fishing communities on Lake Victoria islands in Uganda. Plasma samples from 2881 participants from two household surveys, the baseline (1310 participants) and the final (1571 participants) surveys were tested for KSHV IgG antibody responses to K8.1 and ORF73 recombinant proteins using ELISA. The baseline survey was carried out before the trial intervention while the final survey was carried out after three years of the trial intervention. Additionally, a subset sample of 372 participants from the final survey was tested for IgE, IgG and IgG4 antibody concentrations to S. mansoni adults worm antigen (SWA) and S. mansoni egg antigen (SEA) using ELISA. Infection by helminths (S. mansoni, N. americanus, T. trichiura and S. stercoralis) was diagnosed using real-time PCR, urine circulating cathodic antigen (CCA) and stool microscopy (Kato-Katz method) while malaria infection was diagnosed using microscopy. We analysed the relationship between helminth and malaria infections and KSHV seropositivity using regression modelling, allowing for survey design. At baseline, 56% of the participants were male while 48% of the participants were male in the final survey. The most prevalent helminth infection was S. mansoni (at baseline 52% and 34% in the final survey by microscopy, 86% by CCA and 50% by PCR in the final survey). KSHV seropositivity was 66% (baseline) and 56% (final survey) among those 1-12 years and >80% in those 13+ years in both surveys; malaria parasitaemia prevalence was 7% (baseline) and 4% (final survey). At baseline, individuals infected with S. mansoni (detected by microscopy) were more likely to be KSHV seropositive (aOR = 1.86 (1.16, 2.99) p = 0.012) and had higher anti-K8.1 antibody levels (acoefficient = 0.03 (0.01, 0.06) p = 0.02). In the final survey, S. mansoni (by microscopy, adjusted Odds Ratio (aOR = 1.43 (1.04-1.95), p = 0.028) and malaria parasitaemia (aOR = 3.49 (1.08-11.28), p = 0.038) were positively associated with KSHV seropositivity. Additionally, KSHV seropositive participants had higher S. mansoni-specific IgE and IgG antibody concentrations in plasma. Furthermore, HIV infected individuals on cART were less likely to be KSHV seropositive compared to HIV negative individuals (aOR = 0.46 (0.30, 0.71) p = 0.002). Schistosoma species skew the immune response towards Th2 and regulatory responses, which could impact on KSHV reactivation if co-infected with both organisms.

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.

The Spectrum of Underlying Causes of Iatrogenic Kaposi's Sarcoma in a Large Series: A Retrospective Study

Background:

The frequency of clinicoepidemiological variants of Kaposi's sarcoma (KS) differs markedly throughout the world. The iatrogenic variant is mainly associated with the use of immunosuppressive therapy.

Aims:

We aimed to investigate the distribution of KS variants in our practice and elucidate the underlying causes of iatrogenic KS.

Methods:

Consecutive KS patients seen in a single tertiary center were grouped according to the tumor variants and iatrogenic KS patients were evaluated about associated conditions.

Results:

Among 137 patients, classic variant was the most frequent presentation (n = 88), followed by iatrogenic (n = 37) variant. Among the iatrogenic group, ten were transplant recipients. In 16 iatrogenic KS patients, systemic corticosteroid was used, in four for myasthenia gravis (MG) and in three for rheumatoid arthritis. In three patients, KS developed under topical corticosteroid (TC) treatment. Among iatrogenic KS patients, ten of them had a second primary neoplasm and one had congenital immunodeficiency syndrome.

Conclusions:

Our study revealed one of the highest rates for iatrogenic KS (27%) reported in the literature. Besides well-known causes, relatively frequent association with MG was remarkable. Usage of different forms of TCs was the cause of KS in a few cases.

Infectious Disease Transmission in Solid Organ Transplantation: Donor Evaluation, Recipient Risk, and Outcomes of Transmission

In 2016, the Transplantation Society of Australia and New Zealand, with the support of the Australian Government Organ and Tissue authority, commissioned a literature review on the topic of infectious disease transmission from deceased donors to recipients of solid organ transplants. The purpose of this review was to synthesize evidence on transmission risks, diagnostic test characteristics, and recipient management to inform best-practice clinical guidelines. The final review, presented as a special supplement in Transplantation Direct, collates case reports of transmission events and other peer-reviewed literature, and summarizes current (as of June 2017) international guidelines on donor screening and recipient management. Of particular interest at the time of writing was how to maximize utilization of donors at increased risk for transmission of human immunodeficiency virus, hepatitis C virus, and hepatitis B virus, given the recent developments, including the availability of direct-acting antivirals for hepatitis C virus and improvements in donor screening technologies. The review also covers emerging risks associated with recent epidemics (eg, Zika virus) and the risk of transmission of nonendemic pathogens related to donor travel history or country of origin. Lastly, the implications for recipient consent of expanded utilization of donors at increased risk of blood-borne viral disease transmission are considered.

Nonmelanoma Skin Cancers in Solid-Organ Transplant Recipients: A Single Center Experience

OBJECTIVES

Skin cancers are one of the most common malignancies in solid-organ transplant recipients. Increased age and immunosuppressive drug use are risk factors for posttransplant skin malignancies. We evaluated nonmelanocytic skin cancer incidence and development time in transplant patients.

MATERIALS AND METHODS

We reviewed 1833 patients who received kidney, liver, and heart grafts between 1996 and 2016 at Baskent University. We excluded melanocytic skin cancers, premalignant lesions, and benign skin tumors.

RESULTS

Of 1833 patients, 1253 were male (68.4%) and 580 were female (31.6%), composed of 1133 kidney (61.8%), 512 liver (27.9%), and 120 heart recipients (6.5%). Of these, 22 patients (18 kidney/3 liver/1 heart) developed 23 different types of skin cancer. Prevalence of skin cancer was 1.20%. Mean age at presentation was 55.8 years (range, 37-71 y). Average time from transplant to skin malignancy was 6.1 years (range, 1-13 y), with the most common being basal cell carcinoma (43%, 10 cases), followed by squamous cell carcinoma (39%, 9 cases) and Kaposi sarcoma (13%, 3 cases). Tumor sites included head and neck (15 case), trunk (2 cases), lower extremity (2 cases), and upper extremity (2 cases). Neither local recurrence nor distant metastasis was shown.

CONCLUSIONS

Skin cancer risk is increased in solid-organ transplant recipients versus the general population. Although squamous cell carcinoma is the most common tumor in this patient population, followed by basal cell carcinoma, we found this reversed in our patients. The low prevalence of skin malignancy (1.20%) may be associated with close clinical follow-up to detect premalignant skin lesions and the lowdose immunosuppressive drug regimen. We believe that local recurrence and distant metastasis were absent because we use a wide surgical margin of excision and provide strict follow-up. Routine dermatologic follow-up visits of transplant recipients are recommended to detect and treat early skin cancer and premalignant lesions and thus lower morbidity and mortality.

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.

KSHV and the Role of Notch Receptor Dysregulation in Disease Progression

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of two human cancers, Kaposi's Sarcoma (KS) and primary effusion lymphoma (PEL), and a lymphoproliferation, Multicentric Castleman's Disease (MCD). Progression to tumor development in KS is dependent upon the reactivation of the virus from its latent state. We, and others, have shown that the Replication and transcriptional activator (Rta) protein is the only viral gene product that is necessary and sufficient for viral reactivation. To induce the reactivation and transcription of viral genes, Rta forms a complex with the cellular DNA binding component of the canonical Notch signaling pathway, recombination signal binding protein for Jk (RBP-Jk). Formation of this Rta:RBP-Jk complex is necessary for viral reactivation to occur. Expression of activated Notch has been shown to be dysregulated in KSHV infected cells and to be necessary for cell growth and disease progression. Studies into the involvement of activated Notch in viral reactivation have yielded varied results. In this paper, we review the current literature regarding Notch dysregulation by KSHV and its role in viral infection and cellular pathogenesis.

Oral Localization of Kaposi Sarcoma: Clinical Presentation and Conservative Management

Kaposi sarcoma (KS) caused by human herpes virus type-8 is the most frequent immunosuppression-associated malignancy worldwide and its treatment is still controversial. We report on the clinical management of a patient who developed oral KS after liver transplantation. The disease appeared 1 month after the transplant and recurred after 4 months. The patient represents, to our knowledge, a rare case that was treated successfully only by shifting a conventional immunosuppressive therapy to everolimus alone.

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.

Fatal Outcome of Multiple Clinical Presentations of Human Herpesvirus 8-related Disease After Solid Organ Transplantation

Kaposi sarcoma is the most common human herpesvirus 8 (HHV-8)-related disease described after solid organ transplantation. Multicentric Castleman disease and hemophagocytic syndrome are other potential HHV-8-induced entities but are less frequently reported. We describe the case of a liver transplant recipient who presented with an acute febrile illness 1 year after transplantation with a rapidly fatal outcome. Autopsy revealed 3 distinct HHV-8-related entities: Kaposi sarcoma, HHV-8-associated multicentric Castleman disease with microlymphomas and a severe hemophagocytic syndrome. Retrospective serologic tests suggested that HHV-8 was likely transmitted by the seropositive donor at the time of transplantation. To our knowledge, this is the first case of copresentation of 3 clinical presentations of HHV-8-mediated human disease in the post-transplant setting. Considering the absence of systematic screening of organ donors/recipients for HHV-8 infection, HHV-8-related illness should be suspected in transplant recipients who present with acute febrile illness, systemic symptoms, lymphadenopathies, and/or multiorgan failure to rapidly document the diagnosis and provide timely an adequate treatment.

Human herpesvirus 8 seroconversion in a population-based cohort of men in Tobago

Human herpesvirus 8 (HHV-8) is the causal agent of Kaposi's sarcoma (KS). In Tobago, KS is not common; however, HHV-8 seropositivity has been reported to be 39.9% in men with prostate cancer compared to <22.9% in healthier women and men. To understand HHV-8 transmission, we examined HHV-8 seroconversion and seroreversion, and risk factors for these changes in Tobago men. Serum specimens from a sub-cohort of Tobago Prostate Survey men, aged 40-81 years (n = 381/442), were collected at baseline and a subsequent visit between 3 and 9 years and tested for HHV-8 seropositivity using an immunofluorescence assay for antibodies against HHV-8 lytic antigens. Poisson distribution was used to calculate HHV-8 seroconversion and seroreversion rates and their 95% confidence intervals. Differences in baseline characteristics between HHV-seroconverters versus persistent HHV-8 seronegative men and HHV-8 seroreverters versus HHV-8 seropositive men were examined. HHV-8 seropositivity was 12.3% (N = 381) at baseline, with HHV-8 seropositivity significantly higher in increasing age groups, 40-49 (4.0%) to 70-81 (37.5%) years (P-value trend <0.0001). HHV-8 seroconversion and seroreversion rates were 0.23 per 100 person-years (95% C.I., 0.06-0.58) and 2.42 per 100 person-years (95% C.I., 0.89-5.26), respectively. There were significantly more HHV-8 seroconverters who reported "ever smoked cigarettes of >6 months" at baseline compared to HHV-8 persistent seronegative men (P-value = 0.03). Baseline characteristics of HHV-8 seroreverters did not differ from persistent seropositive men. Low HHV-8 seroconversion and seroreversion rates were found. Data suggest that HHV-8 transmission occurred at earlier ages, <40 years, in Tobago men.

KSHV: pathways to tumorigenesis and persistent infection

Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8) is the etiologic agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. These cancers often occur in the context of immunosuppression, which has made KSHV-associated malignancies an increasing global health concern with the persistence of the AIDS epidemic. KSHV has also been linked to several acute inflammatory diseases. KSHV exists between a lytic and latent lifecycle, which allows the virus to transition between active replication and quiescent infection. KSHV encodes a number of proteins and small RNAs that are thought to inadvertently transform host cells while performing their functions of helping the virus persist in the infected host. KSHV also has an arsenal of components that aid the virus in evading the host immune response, which help the virus establish a successful lifelong infection. In this comprehensive chapter, we will discuss the diseases associated with KSHV infection, the biology of latent and lytic infection, and individual proteins and microRNAs that are known to contribute to host cell transformation and immune evasion.

Skin cancer in kidney transplant recipients

Morbidity and mortality due to skin cancer is excessively high in renal transplant recipients compared to the general population. This epidemiologic difference is mainly due to the severe immunosuppression that enhances ultraviolet-induced DNA damage and leads to reactivation of potential oncogenic viruses. The most common skin cancer in transplant recipients is squamous cell carcinoma followed by basal cell carcinoma, while in the general population this ratio is reversed. Melanoma and cutaneous lymphoma are relatively rare although they occur more frequently in transplant patients than in the general population. Notably some tumors, such as Kaposi's sarcoma, are seldom encountered in the general population while they are frequently observed in transplant recipients. Local recurrences and visceral spreading are not so uncommon and pose a major issue for quality of life and overall prognosis of these patients. Timely diagnosis is essential and may be challenging, since the accuracy of clinical diagnosis is modest; thus skin biopsy is an essential tool for appropriate management. In this review, we describe the most common types of skin cancer in renal transplant recipients, with a focus on pathogenic issues that account for the different epidemiology and clinical expression of these neoplasms in this population.

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.

Human herpesvirus 8 transfusion transmission in Ghana, an endemic region of West Africa

BACKGROUND

Human herpesvirus 8 (HHV-8) seroprevalence ranges between less than 5% in Europe and North America and 50% to 70% in sub-Saharan Africa. Evidence of HHV-8 transfusion transmission is only indirect. We conducted a serologic (anti-HHV-8) and molecular (HHV-8 DNA) study of samples from paired donor-immunocompetent recipients transfused with whole blood.

STUDY DESIGN AND METHODS

Samples from 252 donor-recipient pairs were tested. Immunoglobulin G to HHV-8 was detected with enzyme immunoassays and confirmed with an in-house immunofluorescence assay. The cellular fraction from seroreactive donors and their recipients was tested for HHV-8 DNA.

RESULTS

Anti-HHV-8 was positive (reactive in two or more assays) in 28 (11%) patients and 16 (6%) donors. Of 12 seronegative recipients (at risk of transmission) receiving seropositive blood, one very likely transmission was identified (8.3% confidence interval, 0%-23%). The donor blood contained HHV-8 DNA and his and four other donors' sequences clustered separately from recorded genotypes with a 97% bootstrap constituting a distinct genotype.

CONCLUSIONS

HHV-8 is transmitted in Ghana but does not carry clinical consequences since most patients are immunocompetent. The clinical risk will increase with the availability of immunosuppressive drugs in sub-Saharan Africa. We propose that a new genotype (HHV-8-G for Ghana) be added to the current nomenclature.

Primary and reactivated HHV8 infection and disease after liver transplantation: a prospective study

Human herpesvirus 8 (HHV8) is pathogenic in humans, especially in cases of immunosuppression. We evaluated the risk of HHV8 transmission from liver donors, and its clinical impact in southern Italy, where its seroprevalence in the general population is reported to be as high as 18.3%. We tested 179 liver transplant recipients and their donors for HHV8 antibodies at the time of transplantation, and implemented in all recipients a 12-month posttransplant surveillance program for HHV8 infection. Of the 179 liver transplant recipients enrolled, 10.6% were HHV8 seropositive before transplantation, whereas the organ donor's seroprevalence was 4.4%. Eight seronegative patients received a liver from a seropositive donor, and four of them developed primary HHV8 infection. Two of these patients had lethal nonmalignant illness with systemic involvement and multiorgan failure. Among the 19 HHV8 seropositive recipients, two had viral reactivation after liver transplantation. In addition, an HHV8 seronegative recipient of a seronegative donor developed primary HHV8 infection and multicentric Castleman's disease. In conclusion, primary HHV8 infection transmitted from a seropositive donor to a seronegative liver transplant recipient can cause a severe nonmalignant illness associated with high mortality. Donor screening for HHV8 should be considered in geographic areas with a high prevalence of such infection.

Human herpes virus type 8-associated Kaposi sarcoma in a pediatric liver transplant recipient

  Development of KS in pediatric liver transplant recipients is a rare entity and has dismal prognosis. Latent HHV-8 infection, immunosuppression, and genetic predisposition are possible etiological factors. Decreasing the dose or cessation of immunosuppressive drugs, switching to sirolimus with antiproliferative and antitumor properties, and different chemotherapeutic regimens are the current therapeutic strategies. We herein report a pediatric liver transplant recipient who developed generalized KS at post-transplant fifth month. The disease had an aggressive course despite the highly toxic chemotherapy. On the other hand, a prompt and durable response was provided by paclitaxel with tolerable side effects. The patient is now free of disease for at least 24 months and healthy with good graft function under sirolimus therapy as maintenance immunosuppression. Instead of highly toxic chemotherapy, paclitaxel can be used as therapeutic option in cases with generalized disease and in those who are unresponsive to conventional chemotherapy. However, new studies are needed to assess the efficacy of the paclitaxel therapy in KS in the liver transplant recipients.

Sirolimus-induced signaling modifications in Kaposi's sarcoma with resolution in a liver transplant recipient

Sirolimus is one treatment option in transplant recipients with Kaposi's sarcoma (KS), which involves dysregulation of Akt-mammalian target of rapamycin (mTOR) signaling pathway. Signal modifications after sirolimus therapy in organ recipients with KS are largely unknown and not verified. We reported a case of KS found two yr after liver transplantation in which the immunosuppression was changed from tacrolimus, MMF, and steroid to sirolimus alone. In skin, which was found to have persistent KS after a two-month treatment of sirolimus and was removed completely one yr later, KS was no longer present. The patient went well without graft rejection. Tumor biopsies were performed before, two months, and one yr after the start of sirolimus. Immunohistochemical staining of vascular endothelial growth factor (VEGF), p-Akt, p-mTOR, p-p70 S6 kinase, and Western blot for p-tuberin/ tuberous sclerosis complex (TSC)2 was performed. VEGF was suppressed thoroughly in two-month use of sirolimus. In addition, p-Akt and p-mTOR, which were decreased at two months, could not be detected after one yr of treatment. Moreover, p-p70 S6 kinase, expressed strongly in overlying epidermis initially, was suppressed completely after two months of treatment. However, p-tuberin/TSC2, contrary to suggested theoretically, was not detected through all specimens, implying not to be a significant event. Suppressed expression of VEGF, p-Akt, and p-mTOR was the major event of signaling modification through the long-term use of sirolimus.

K13 blocks KSHV lytic replication and deregulates vIL6 and hIL6 expression: a model of lytic replication induced clonal selection in viral oncogenesis

BACKGROUND

Accumulating evidence suggests that dysregulated expression of lytic genes plays an important role in KSHV (Kaposi's sarcoma associated herpesvirus) tumorigenesis. However, the molecular events leading to the dysregulation of KSHV lytic gene expression program are incompletely understood.

METHODOLOGY/PRINCIPAL FINDINGS

We have studied the effect of KSHV-encoded latent protein vFLIP K13, a potent activator of the NF-kappaB pathway, on lytic reactivation of the virus. We demonstrate that K13 antagonizes RTA, the KSHV lytic-regulator, and effectively blocks the expression of lytic proteins, production of infectious virions and death of the infected cells. Induction of lytic replication selects for clones with increased K13 expression and NF-kappaB activity, while siRNA-mediated silencing of K13 induces the expression of lytic genes. However, the suppressive effect of K13 on RTA-induced lytic genes is not uniform and it fails to block RTA-induced viral IL6 secretion and cooperates with RTA to enhance cellular IL-6 production, thereby dysregulating the lytic gene expression program.

CONCLUSIONS/SIGNIFICANCE

Our results support a model in which ongoing KSHV lytic replication selects for clones with progressively higher levels of K13 expression and NF-kappaB activity, which in turn drive KSHV tumorigenesis by not only directly stimulating cellular survival and proliferation, but also indirectly by dysregulating the viral lytic gene program and allowing non-lytic production of growth-promoting viral and cellular genes. Lytic Replication-Induced Clonal Selection (LyRICS) may represent a general mechanism in viral oncogenesis.

Kaposi's sarcoma after liver transplantation

INTRODUCTION

Kaposi's Sarcoma (KS) is a malignant neoplasm arising from endothelial cells. HHV8-infection represents a key pathogenic determinant for the development of KS. There are no standard criteria to treat KS in immunosuppressed-individuals. Six cases (2.1%) of KS occurred in our Center among 285-recipients who underwent liver transplantation (LT) between October 2000 and November 2006.

METHODS

Patients were four males and two females. Mean age was 57 years (range 44-65). Indication for LT was ESLD associated/non-associated with hepatocellular carcinoma (HCC). The immunosuppressive regimen consisted of cyclosporine/tacrolimus associated with steroids or daclizumab. HHV8-detection was performed by the serological method before LT, and by polymerase chain reaction (PCR)-analysis after KS.

RESULTS

One patient had HCV-related cirrhosis and coinfection from HIV, three had HBV-related cirrhosis, two of these with coexistent HCC. The last two patients had alcoholic-cirrhosis, one with coexistent HCC. Mean time from transplantation to KS was 6.2 months (range 3.8-8.8). Three patients were treated with doxorubicin and three with switch from calcineurin-inhibitors to sirolimus. Three patients expired after 11.5, 8.8, and 7.4 months from KS diagnosis.

DISCUSSION

KS should be treated by a multidisciplinary approach to obtain an early diagnosis and best management. Effective treatment with immunosuppression reduction or switch to sirolimus is mandatory and can induce complete regression.

Risk Assessment of Immunosuppressive Therapy in Facial Transplantation

BACKGROUND

Immunosuppression-related risks are foremost among ethical concerns regarding facial transplantation. However, previous risk estimates are inaccurate and misleading, because they are based on data from studies using different immunosuppression regimens, health status of the transplant recipients, tissue composition, and antigenicity. This review provides a comprehensive risk assessment for facial transplantation based on comparable data of immunosuppression, recipient health status, and composition and antigenicity of the transplanted tissue.

METHODS

The risk estimates for face transplantation presented here are based on data reported in clinical kidney (10-year experience) and hand transplantation (5-year experience) studies using tacrolimus/mycophenolate mofetil/corticosteroid therapy. Mitigating factors including ease of rejection diagnosis, rejection reversibility, infection prophylaxis, patient selection, and viral serologic status are taken into account.

RESULTS

Estimated risks include acute rejection (10 to 70 percent incidence), acute rejection reversibility (approximating 100 percent with corticosteroid therapy alone), chronic rejection (<10 percent over 5 years), cytomegalovirus disease (1 to 15 percent), diabetes (5 to 15 percent), hypertension (5 to 10 percent), and renal failure (<5 percent).

CONCLUSIONS

A review of these data indicates that previously reported estimates of immunosuppression-related risks are outdated and therefore should no longer be used. These updated risk estimates should be used by facial transplant teams, institutional review boards, and potential recipients when considering the immunologic risks associated with facial transplantation.

Evaluation of Posttransplantation Malignancies Compared With De Novo Tumors

It is uncertain whether tumors arising in transplant patients resemble ones that develop de novo in pathogenesis, morphology, and behavior. This study sought to investigate some clinical, morphological, and immunohistochemical features of several posttransplantation malignancies compared with similar de novo tumors. The study group consisted of 40 malignant tumors encountered in 1350 transplant patients (1229 kidneys, 113 livers, 8 hearts) between 1986 and 2006. Tumors with 3 or more examples were compared with randomly selected controls. These included Kaposi's sarcoma (n=14); extranodal lymphoma (n=9); squamous cell carcinoma (n=6); and nodal lymphoma (n=3). The variables that were analyzed were the localization, predisposing lesions, degree of differentiation, and host response. For lymphomas, we also determined histological subtype, origin, and Ki-67 proliferation index. Most tumors (36/40, 90%) occurred in patients with renal transplants. However, the relative frequency was higher among liver transplant cases (3.53% vs 2.92% for kidney transplants). No malignancy was seen in heart transplant cases. Squamous cell carcinomas were better differentiated (P<.05) compared with controls and they were more frequently associated with precursor lesions (P<.05). Kaposi's sarcomas involved internal organs more frequently in posttransplant patients, and the Ki-67 proliferation index was higher in posttransplantation nodal lymphomas. However, these factors were not significantly different (P>.05). Our findings suggested that certain posttransplantation malignancies display unique characteristics compared with their de novo counterparts.

Seroprevalence of Human Herpes Virus-8 in Renal Transplant Recipients: A Single Center Study From Iran

The long-term risk of malignancy among renal transplant patients is approximately 100 times that of the general population. Unlike North America and many European countries, Kaposi's sarcoma is the most common cancer after renal transplantation in most series reported from the Middle East. Human herpes virus-8 (HHV-8) has a major role in the pathogenesis of Kaposi's sarcoma. The risk of posttransplantation Kaposi's sarcoma is 23% to 28% among seropositive patients compared with 0.7% among seronegative patients. This study was conducted to investigate the seroprevalence of HHV-8 among our transplant recipients. The sera from 100 renal transplant recipients were examined by indirect immunofluorescence against latent nuclear antigen. Sixty of 100 patients were males. The overall mean age was 41.1 years (range, 17-74 years) with 17 patients older than 55 years. The mean transplantation duration was 41.6 months. Twenty-five percent of patients were seropositive for HHV-8. There was statistically significant seropositivity for HHV-8 among recipients older than 55 years (P=.02). Eight of 17 patients older than 55 years were seropositive (47%), whereas 17/83 patients younger than 55 years were seropositive (20%). There were no significant differences for HHV-8 seropositivity regarding sex, transplantation duration, and immunosuppressive regimen, including dose of immunosuppressive drugs and cyclosporine blood levels. In this study, we showed seropositivity for HHV-8 among a significant percentage of our renal transplant recipients, a finding which may render them at risk to develop Kaposi's sarcoma. Seropositive and seronegative patients were followed for 16 months. One HHV-8 seropositive patient (1/25) developed Kaposi's sarcoma.

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.

In vitro and in vivo replication of seal gammaherpesviruses in cells of multiple species

Phocid herpesvirus virus type 2 (PhHV-2), a putative gammaherpesvirus of seals, has been isolated from harbor seals (Phoca vitulina) and grey seals (Halichoerus grypus). In the present study, different PhHV-2 isolates were shown to have a broad in vitro tropism for various cell types from several mammalian species. Inbred mice and two species of non-human primates proved to be susceptible to experimental infection with PhHV-2. The development of myoepitheliomas and spleen hyperplasia upon cyclosporin A treatment in some of the PhHV-2-infected animals warrants further investigation of the oncogenic and zoonotic potential of this virus.

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.

Human herpesvirus-8 infection and Kaposi's sarcoma after liver and kidney transplantation in different geographical areas of Spain

Since data on human herpesvirus 8 (HHV-8) infection in Spain is not available, our purpose was to determine the prevalence of HHV-8 infection and the risk of developing Kaposi's sarcoma (KS) among organ transplant recipients in different geographical areas of Spain. The study population consisted of 1019 liver and kidney transplant recipients recruited in four transplant units in Spain. Only post-transplant serum samples were available for all participants. IgG anti-HHV-8 latent and lytic antigens were detected by using an indirect immunofluorescence assay as well as enzyme-linked immunosorbant assays. In available samples, HHV-8 DNA genome was detected by using a nested polymerase chain reaction in sera, blood mononuclear cells and KS tissues. The prevalence of HHV-8 infection after transplantation was calculated. To determine risk factors for infection, odds ratios (OR) and 95% confidence intervals (CI) were also calculated. Of the 788 kidney transplants, 5 (0.6%) were HHV-8-positive shortly after transplantation. Of the 231 liver transplant individuals, 8 (3.4%) developed IgG anti-HHV-8 antibodies after transplantation. Thus, incidence of HHV-8 infection is significantly higher among liver transplant recipients in comparison with that in the control population (OR=6, 95% CI=1.2-28.5, p<0.05). In this series, HHV-8 prevalence in liver transplant recipients was higher in the northern (6.6-6.9%) than in the central (2.9%) or the southeastern (1.4%) areas of Spain. Four renal transplant recipients (0.5%) and five of the liver transplant recipients (2.16%) developed KS after transplantation. Time of KS diagnosis after transplant is significantly higher in kidney transplant patients (33.7 months) than in liver transplant recipients (10.4 months), indicating that the latter have a higher risk of developing KS.

Cell signaling pathways engaged by KSHV

Kaposi's sarcoma herpesvirus (KSHV) is the eighth human herpesvirus discovered in 1994 from Kaposi's sarcoma lesion of an AIDS patient. The strong molecular and epidemiological links associating KSHV with Kaposi's sarcoma and certain lymphoproliferative disorders indicate that KSHV is required for the development of these malignancies. Although KSHV is equipped to manipulate and deregulate several cellular signaling pathways, it is not yet understood how this leads to cell transformation. Profound understanding of the interplay of viral and cellular factors in KSHV-infected cells will provide valuable information on the mechanisms of viral tumorigenesis and enable development of efficient targeted therapies for virus-induced cancers. This review focuses on the cellular signaling pathways that KSHV gene products impinge on and discusses their putative contribution to tumorigenesis.

Pretransplantation prevalence of human herpes virus 8 antibodies in kidney donors and recipients in Athens, Greece

AIM

The aim of this study was to estimate the prevalence of anti-human herpes virus 8 (HHV8) antibodies in a cohort of renal donors and recipients in Athens, Greece. HHV8, the etiological agent of posttransplantation Kaposi's sarcoma, causes significant morbidity and mortality.

METHODS

Serum samples from 97 subjects (49 donors and 48 recipients) were tested with an enzyme-linked immunosorbent assay (ELISA) prior to renal transplantation.

RESULTS

Only 2 subjects (both transplant recipients) were found to be anti-HHV8-positive. Both subjects were of Albanian origin.

CONCLUSION

Infection with HHV8 appears to be limited in the Greek population. However, in light of significant long-term morbidity with which HHV8 is related in immunocompromized patients, studies on the general population are needed to estimate the prevalence of HHV8 infection in the country and devise clear guidelines for pretransplantation screening and posttransplantation follow-up.

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.

Human Herpesvirus 8 Infection in Hemodialysis Patients

BACKGROUND

The aim of the present study was to evaluate human herpesvirus 8 (HHV-8) seroprevalence in Greek hemodialysis patients. Patterns of change in HHV-8 serostatus (seroconversions and seroreversions) over time were also evaluated.

METHODS

Serum samples obtained from a cohort of 485 Greek hemodialysis patients were tested for antibodies to HHV-8 by whole virus lysate enzyme-linked immunosorbent assay, and reactive samples were confirmed by means of the orf-73 enzyme-linked immunosorbent assay. HHV-8 seroprevalence at study entry and the incidence of seroreversions and seroconversions per 100 person-years were estimated.

RESULTS

The prevalence of HHV-8 antibodies in Greek hemodialysis patients at enrollment was 7.2%. No univariate associations were established between HHV-8 serostatus and patients' characteristics. Incidences of seroreversions and seroconversions were 16.4/100 person-years (95% confidence interval, 7.1 to 32.3) and 0.28/100 person-years (95% confidence interval, 0.03 to 1.02), respectively. Patients 50 years and younger had an increased probability for seroreversion to HHV-8 antibodies than patients older than 50 years (log-rank test, P = 0.018).

CONCLUSION

We observed a fair number of seroreversions and a low incidence of seroconversion to HHV-8 infection in hemodialysis patients in Greece. Our data provide indirect evidence that HHV-8 transmission in the hemodialysis setting is uncommon.