Serologic association of human herpesvirus eight with posttransplant Kaposi's sarcoma in Saudi Arabia

Evaluating Kaposi Sarcoma in Kidney Transplant Patients: A Systematic Review and Meta-Analysis

Kaposi's sarcoma (KS) is a malignancy that commonly appears as lesions on the skin or mucosal surfaces but can also develop in other organs. This cancer is usually caused by the human herpesvirus 8 (HHV-8), recently known as Kaposi's sarcoma-associated herpesvirus (KSHV). KS is rare in the general population but can develop in kidney transplant recipients with varying incidence due to immunocompromised status from immunosuppression. The main aim of the present systematic review was to identify the prevalence and treatment of KS in kidney transplant patients. PubMed, Cochrane Library, and Google Scholar databases were searched for studies until October 2023. Full-text studies with similar research objectives were included, while non-English articles, reviews, case reports, ongoing clinical trials, and studies evaluating KS in HIV patients or after other solid organ transplants were excluded. All studies were observational; therefore, methodological quality was assessed using the Newcastle-Ottawa Scale. The statistical analyses were performed with the Comprehensive Meta-Analysis (CMA) software (Biostat, Inc. Englewood, NJ). The pooled analysis from the 15 studies included showed that KS develops in 1.5% of kidney transplant recipients and is more prevalent in African (1.7%) and Middle Eastern (1.7%) recipients than in Western recipients (0.07%). KS was also significantly more prevalent among male recipients than female recipients (OR: 2.36; p < 0.0001). Additionally, cyclosporine-based immunosuppression accounts for most KS incidences (79.6%) compared to azathioprine-based immunosuppression (28.2%). Furthermore, reduction or withdrawal of immunosuppression alone resulted in 47.8% KS complete remissions. Post-kidney transplantation KS is more frequent among males and patients of Middle Eastern and African origin. However, the gender difference may be attributed to most patients undergoing kidney transplants being male. Therefore, if gender balance is considered in future studies, then the difference might be insignificant. Based on our results, we can concur that the mainstay treatment for post-transplant KS is reduction or withdrawal of immunosuppression. However, the patients should be closely monitored to avoid KS recurrence and kidney rejection. Furthermore, there is an increased risk for KS with the use of cyclosporine-based immunosuppression. However, this does not mean that the withdrawal of this immunosuppression agent might result in improved KS outcomes because the withdrawal of azathioprine with or without cyclosporine reduction has also led to improved outcomes.

Diabetes and risk of Kaposi's sarcoma: effects of high glucose on reactivation and infection of Kaposi's sarcoma-associated herpesvirus

Patients with diabetes are generally prone to pathogen infection and tumor progression. Here, we investigated the potential association between diabetes and Kaposi's sarcoma (KS), a tumor linked to infection with Kaposi's sarcoma-associated herpesvirus (KSHV). By using Taiwan's National Health Insurance Research Database, we found that diabetes is statistically associated with increased risk of KS in a case-control study. Since a high level of blood sugar is the hallmark of diabetes, we determined whether high glucose promotes both KSHV reactivation and infection, which are crucial for KS pathogenesis. Our results showed that high glucose significantly increases lytic reactivation of KSHV but not Epstein-Barr virus, another related human oncogenic gammaherpesvirus, in latently infected cells. Activation of the transcription factor AP1 by high glucose is critically required for the onset of KSHV lytic reactivation. We also demonstrated that high glucose enhances susceptibility of various target cells to KSHV infection. Particularly, in endothelial and epithelial cells, levels of specific cellular receptors for KSHV entry, including integrin α3β1 and xCT/CD98, are elevated under high glucose conditions, which correlate with the enhanced cell susceptibility to infection. Taken together, our studies implicate that the high-glucose microenvironment may be an important predisposing factor for KS development.

Oral Kaposi Sarcoma in HIV-seronegative Saudi patient: Literature review and case report

Kaposi Sarcoma (KS) is an intermediate neoplasm affecting the endothelial cells of mucous membranes and skin. It arises most commonly among HIV-infected individuals. We present an intra-oral KS in an 80-year-old Saudi male patient, who is HIV-seronegative, non-immunosuppressed, and with no history of organ transplantation. The patient was treated with fractionated radiation therapy, and had no recurrence in the 48 months of follow-up. The clinical disease, histologic features, and treatment modality used, as well as the relative literature are presented in this paper.

HPV Infection, but Not EBV or HHV-8 Infection, Is Associated with Salivary Gland Tumours

Benign and malignant salivary gland tumours are clinically heterogeneous and show different histology. Little is known about the role of human herpes virus 8 (HHV-8), Epstein-Barr virus (EBV), and human papillomavirus (HPV) infection in salivary gland neoplasms. We investigated the presence of the three viruses in formalin-fixed, paraffin-embedded tissue samples in a cohort of 200 different salivary gland tumours. We performed EBV-LMP-1 and HHV-8 and p16 immunohistochemistry, a specific chip based hybridization assay for detection and typing of HPV and a chromogenic in situ hybridization for EBV analysis. Only one case, a polymorphic low-grade carcinoma, showed HHV-8 expression and one lymphoepithelial carcinoma was infected by EBV. In 17 cases (9%) moderate or strong nuclear and cytoplasmic p16 expression was detected. The HPV type was investigated in all of these cases and additionally in 8 Warthin's tumours. In 19 cases HPV type 16 was detected, mostly in Warthin's tumour, adenoid cystic carcinoma, and adenocarcinoma NOS. We concluded that HHV-8 infection and EBV infection are not associated with salivary gland cancer, but HPV infection may play a role in these tumour entities.

Oncogenic Virus Infections in the General Population and End-stage Renal Disease Patients With Special Emphasis on Kaposi's Sarcoma Associated Herpes Virus (KSHV) in Northeast of Iran

BACKGROUND

Globally, almost 20% of cancers are related to infectious agents that can be prevented. Oncogenicity refers to viruses that may cause cancers, more importantly in immunocompromised subjects such as transplant and hemodialysis patients. Therefore, epidemiological studies are the first line for understanding the importance of these agents in public health, particularly, in mobile populations, tourism and pilgrimage regions.

OBJECTIVES

Oncogenic viral infections, such as hepatitis B virus (HBV), hepatitis C virus (HCV) and Epstein-barr virus (EBV) are the most common viral agents in immunocompromised patients. Furthermore, human T lymphocyte virus type I (HTLV-I), due to endemicity in Khorasan Razavi province located northeast of Iran as a pilgrimage region, and Kaposi's sarcoma associated herpes virus (KSHV), as an oncogenic herpesvirus in immunocompromised subjects have been investigated among the general population and those with end-stage renal diseases (ESRD).

PATIENTS AND METHODS

A cross-sectional study was carried out among 1227 randomly selected individuals; 25 donors and 195 patients with ESRD, including 60 kidney transplant recipients and 135 dialysis patients from the Khorasan Razavi province, Iran. Serological tests were carried out using commercial enzyme-immunoassay kits. To confirm positive serology tests, the extracted viral DNA or RNA was examined for the presence of KSHV, HTLV-I and HCV by conventional PCR.

RESULTS

The prevalence of KSHV infection in the general population was 1.71% (21/1227); 2.60% (10/384) males and 1.30% (11/843) females. In kidney transplants, viral infections occurred in 23.3% of subjects; including EBV, HTLV-I and HBV-HCV co-infection in 8.3%, 3.3% and 1.7%, respectively. In patients on hemodialysis, viral infections were present in 29.6% including EBV, HTLV-I and HBV-HCV co-infection in 2.2%, 5.9% and 16.3%, respectively. Seroprevalence of KSHV in patients with kidney transplants was 1.7% and in patients on dialysis was 3.0%. Furthermore, KSHV and HTLV-I genome was detected in 25% and 100% of seropositive subjects, respectively.

CONCLUSIONS

In conclusion, this study demonstrated that these tumor virus infections including HTLV-I, KSHV and particularly hepatitis viruses (HBV plus HCV) are prevalent in the general population and in patients on hemodialysis, which might be an important health concern in this region due to the mobile population.

Vascular endothelial growth factor A polymorphism and risk of Kaposi's sarcoma herpesvirus viremia in kidney allograft recipients

BACKGROUND

Kaposi's sarcoma herpesvirus (KSHV) causes Kaposi's sarcoma (KS), primary effusion lymphoma, and multicentric Castleman's disease in immunocompromised patients including allograft recipients. Detection of KSHV DNA in blood, as well as host genetic polymorphisms has been found to be associated with an increased risk for KS. We investigated an association between single nucleotide polymorphisms (SNPs) in vascular endothelial growth factor A (VEGFA) gene region and KSHV viremia in kidney transplant recipients (KTR) in Saudi Arabia.

METHODS

In total, 152 KTR who have survived kidney transplantation for at least 6 months were included in the study. KSHV viremia was determined by real-time polymerase chain reaction (PCR). Genotyping of SNPs in the VEGFA region was performed by PCR and direct sequencing, as well as by restriction fragment length polymorphism.

RESULTS

KSHV DNA was detected in 28.9% (n = 44) of the study population. The A-allele at position C172A VEGFA gene promoter region was found to be associated with KSHV viremia (odd ratio [OR] = 4.8, P = 0.005). In addition, the G-allele at position C+405G in the 5'-untranslated region was associated with KSHV viremia in women, but not in men (OR = 3.98, P = 0.004).

CONCLUSIONS

Our results suggest an association of VEGFA polymorphisms with KSHV viremia among KTR in this study population. A limitation of our study is that the results can only be predicated for patients 6 months after kidney transplantation and should be validated in another cohort with larger sample size.

Tonsillar Kaposi sarcoma in a patient with membranous glomerulonephritis on immunosuppressive therapy

Kaposi sarcoma is a malignant vascular neoplasm uncommonly seen in immunosuppressed patients. Herein we report an unusual case of tonsillar Kaposi sarcoma in a patient with membranous glomerulonephritis treated with prednisolone and cyclosporine. The patient presented after 10 months of starting the treatment with a tonsillar mass. Histological examination was typical of monomorphic spindle cell proliferation with slit-like vascular channels. The tumor cells expressed CD34, D2-40 and positive nuclear stain for HHV-8. Kaposi sarcoma is associated with immunosuppression and rarely occurs in the tonsil. Clinicians should be aware of this rare presentation of Kaposi sarcoma.

PGP 9.5 neuronal marker may differentiate immunohistochemically HIV-related from Mediterranean and immunosuppression-associated Kaposi's sarcoma

Mediterranean Kaposi's sarcoma (MKS), HIV-related KS (HIV-KS) and immunosuppression-associated KS (IS-KS), caused by human herpes virus 8 (HHV-8), share similar histological features. The aim of this study was to investigate differences in epidermal nerve fibers (ENFs) between the three KS types and controls. Skin biopsies from 23 HIV-KS, 16 MKS, 28 IS-KS patients and 18 controls, age-gender matched, were immunostained with PGP 9.5; ENFs in upper epidermal layer (EL) and penetrating the basement membrane were measured. The mean number of nerve fibers penetrating ENFs was significantly lower in HIV-KS (p < 0.001) compared to all other groups. MKS and IS-KS had comparable ENFs but lower than controls (p < 0.00 1). In the upper EL all groups had comparable ENFs and lower than controls. In conclusion, HIV-KS can be distinguished histologically from other types, by counting ENFs. Moreover, KS is associated with decreased ENFs, which may be a histological reflection of nerve damage. This is even more pronounced in HIV-KS patients and could be explained by a neurotoxic action of HHV-8, HIV, and their co-existence.

Seroprevalence of Human herpesvirus 8 (HHV-8) and incidence of Kaposi's sarcoma in Iran

Seroepidemiological surveys show that the prevalence of human herpesvirus 8 (HHV-8) infection mostly varies in various geographical areas and reflects the local incidence of classic and endemic KS, being widespread in sub-Saharan Africa and Mediterranean countries and uncommon in the USA and Northern Europe. In the Middle East only few populations, such as Ashkenazi and Sephardic groups in Israel, have been adequately evaluated for HHV-8 seroprevalence. Among Iranian population a striking higher seroprevalence of HHV8 has been reported among haemodialysis (16.9%), renal transplant recipients (25%) and HIV (45.7%) patients compared to blood donors (2%). Kaposi's sarcoma (KS) is the rarest cancer in Iran, with an annual age-standardized incidence varying from 0.10 to 0.17 per 100,000 in males and from 0.06 to 0.08 per 100,000 in females. KS, however, is one of the most important malignancies in Iranian renal transplanted patients affecting up to 2.4% of organ recipients. The epidemiology of HHV8 and KS in Iran needs further evaluation. While the high prevalence of HHV-8 antibodies in HIV positive and haemodialysis individuals may be attributed to high-risk sexual behavior and polytransfusions, respectively, unknown determinants may be responsible for high seroprevalence of HHV8 and high incidence of KS in solid organ recipients. A global survey on HHV8 seroprevalence in Iran is mandatory to define co-factors associated with HHV8 infection and KS risk in the general Iranian population and in specific patient groups.

Malignancy after renal transplantation: the role of immunosuppression

Outcomes of kidney transplantation, in terms of graft and patient survival, have improved over the past few decades, partly as a result of the introduction of new immunosuppressive drugs. Many immunosuppressive agents are associated with an increased risk of cardiovascular events and an increased risk of cancer, however, which can compromise patient survival. Cancer is more common among solid-organ transplant recipients than it is in the general population or in patients on dialysis. In fact, malignancy is the third most common cause of death in renal transplant recipients. Immunosuppressive treatments used in renal transplant recipients can cause malignancy by supporting oncogenesis caused by certain viruses or by impairing immune surveillance thereby enabling faster tumor growth. In this Review, we describe the epidemiological and clinical characteristics of common tumor types occurring after kidney transplantation, and the etiopathogenetic factors that lead to their appearance, with a particular focus on the relationship between immunosuppressive treatment and malignancy. Immunosuppressive drugs associated with an increased risk of malignancy after transplantation are also discussed, as are immunosuppressive drugs that seem to have antioncogenic properties.

Induction of protective immunity against murine gammaherpesvirus 68 infection in the absence of viral latency

Human gammaherpesviruses, Epstein-Barr virus, and human herpesvirus 8/Kaposi's sarcoma-associated herpesvirus are important pathogens associated with diseases, including lymphomas and other malignancies. Murine gammaherpesvirus 68 (MHV-68) is used as an experimental model system to study the host immune control of infection and explore novel vaccine strategies based on latency-deficient live viruses. We studied the properties and the potential of a recombinant MHV-68 (AC-RTA) in which the genes required for persistent infection were replaced by a constitutively expressed viral transcription activator, RTA, which dictates the virus to lytic replication. After intranasal infection of mice, replication of AC-RTA in the lung was attenuated, and no AC-RTA virus or viral DNA was detected in the isolated splenocytes, indicating a lack of latency in the spleen. Infection of the AC-RTA virus elicited both cellular immune responses and virus-specific IgG at a level comparable to that elicited by infection of the wild-type virus. Importantly, vaccination of AC-RTA was able to protect mice against subsequent challenge by the wild-type MHV-68. AC-RTA provides a vaccine strategy for preventing infection of human gammaherpesviruses. Furthermore, our results suggest that immunity to the major latent antigens is not required for protection.

Avoiding pitfalls: what an endoscopist should know in liver transplantation--part II

Over the last decade the number of patients undergoing transplantation has increased. At the same time, effective peri- and postoperative care and better surgical techniques have resulted in greater numbers of recipients achieving long-term survival. Identification and effective management in the form of adequate treatment is essential, since any delay in diagnosis or treatment may result in graft loss or serious threat to patient's life. Various aspects of endoscopic findings that can be commonly encountered among liver transplant recipients are discussed herein. Topics include: persistent and/or recurrent esophageal varices, reflux, Candida or cytomegalovirus (CMV) esophagitis, esophageal neoplasms, posttransplant peptic ulcer, biliary complications, posttransplant lymphoproliferative disorder (PTLD), Kaposi's sarcoma, CMV colitis and inflammatory bowel disease, colonic neoplasms, Clostridium difficile infection, and graft versus host disease (GVHD).

Successful treatment of a child having generalized Kaposi's sarcoma after living donor liver transplantation with conversion to sirolimus

SRL is a new and potent immunosuppressive agent that has been successfully introduced in organ transplantation. In contrast to other immunosuppressive agents, SRL has a potent antitumor activity both in vitro and in vivo. Herein, we report a child with Kaposi's sarcoma that was diagnosed 30 months after LDLT and treated successfully with only conversion to SRL monotherapy. KS regressed completely at the end of the first month and remained in remission during 28 months follow-up.

Postkidney transplant malignancy in Egypt has a unique pattern: a three-decade experience

The pattern of posttransplant malignancy varies among transplant units. We report on our single-center experience. Between 1976 and 2007, 1866 kidney transplantations were carried out (1390 males and 476 females, mean age 29.84+/-10.47 years). Recipients who developed posttransplant malignancy were evaluated (74 patients, 3.97%). Furthermore, their data were compared with those of the malignancy-free recipients (1792 patients). Kaposi sarcoma was the commonest type (36.8%) and had the shortest transplant-to-malignancy period (mean 2.84 years). The lesions were only cutaneous in 75% of cases. Skin cancers were the fourth among posttransplant malignancies (9.2%) and 85.7% of cases were basal cell carcinoma. In our series, age and prior blood transfusion were identified as independent risk factors for the development of posttransplant malignancy. In conclusion, the prevalence and type of posttransplant malignancy vary because of many factors including environmental and genetic factors. In our series, Kaposi sarcoma was the commonest type and, therefore, needs further evaluation.

Kaposi sarcoma: a continuing conundrum

Kaposi sarcoma (KS) remains a challenge. Its classic or Mediterranean form tends to be benign. In transplant recipients it may be less so. As part of the AIDS pandemic, of which it was an original defining component, it may be life-threatening. It is due to human herpesvirus-8, which is necessary but not sufficient to produce the disease. KS has a low prevalence in the general population of the United States and United Kingdom, with an intermediate rate in Italy and Greece, and a high one in parts of Africa. In Italy, hot spots include its southern regions, the Po River Valley, and Sardinia, possibly related to a high density of blood-sucking insects. An important challenge is to treat KS patients without immunocompromising them. The potential of effective anti-herpes virus therapy and the use of sirolimus in transplantation recipients have added new opportunities for KS prevention.

LEARNING OBJECTIVES

At the conclusion of this learning activity, participants should be able to provide the most recent information about Kaposi sarcoma in the context in which it occurs. Its classic or Mediterranean form, its pattern in transplant recipients and others iatrogenically immunosuppressed, and its occurrence as a potentially life-threatening part of the AIDS pandemic will be stressed. Its etiology and transmission will be discussed in detail to facilitate understanding of Kaposi sarcoma and of human herpesvirus-8 infection in the general population of the United States and United Kingdom, in Italy and Greece, and in certain parts of Africa. Its therapy, including the concept of doing it without immunocompromising the patient, will be stressed. New opportunities for Kaposi sarcoma prevention will also be discussed.

Valganciclovir for suppression of human herpesvirus-8 replication: a randomized, double-blind, placebo-controlled, crossover trial

BACKGROUND

Human herpesvirus-8 (HHV-8) replication is critical in the induction and maintenance of Kaposi sarcoma, primary effusion lymphoma, and some cases of Castleman disease. In vitro and observational studies suggest that ganciclovir inhibits HHV-8 replication, but no randomized clinical trials have been conducted.

METHODS

A total of 26 men infected with HHV-8 were randomized to receive 8 weeks of valganciclovir administered orally (900 mg once per day) or 8 weeks of placebo administered orally. After a 2-week washout period, participants in each group received the study drug they had not yet taken (either valganciclovir or placebo), for 8 additional weeks. Oral swab samples were collected daily during the study, and HHV-8 and CMV DNA were quantified by real-time PCR.

RESULTS

A total of 16 human immunodeficiency virus (HIV)-positive men and 10 HIV-negative men enrolled in and completed the study. Of the 3,439 swab samples that participants had been expected to provide, 3029 (88%) were available for analysis. HHV-8 was detected on 44% of swabs collected from participants who were receiving placebo, compared with 23% of swabs collected from participants who were receiving valganciclovir (relative risk [RR], 0.54 [95% confidence interval {CI}, 0.33-0.90]; P = .02). Valganciclovir reduced oropharyngeal shedding of cytomegalovirus by 80% (RR, 0.20 [95% CI, 0.08-0.48]; P < .001). Shedding of HHV-8 and shedding of cytomegalovirus were independent. Hematologic, renal, or hepatic toxicities were no more common among participants who received the active drug, compared with those who received placebo, though participants who received valganciclovir reported more days of diarrhea.

CONCLUSIONS

Valganciclovir administered orally once per day is well tolerated and significantly reduces the frequency and quantity of HHV-8 replication.

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.

The history of renal transplantation in the Arab world: a view from Saudi Arabia

The first successful renal transplantation in the Arab world took place in Jordan in 1972. Surprisingly, the kidney transplanted was from a non-heart-beating deceased donor. Many Arab countries followed suit, starting their transplantation programs in the 1970s and 1980s, but all were from living related donors. Very few Arab countries managed to start deceased donor programs, notable among which is the Kingdom of Saudi Arabia. Religion has an important part in personal life and government legislation in the Arab world; thus, organ procurement and transplantation had to wait for religious edicts (fatwas) to be passed about the permissibility of organ donation and brain death diagnosis before starting transplantation activities. In Saudi Arabia, the renal transplantation service went through several developmental phases, culminating in the establishment of the Saudi Center for Organ Transplantation, which has become the prototype of a successful multiorgan procurement center to be emulated by Arab and Muslim countries. The story of transplantation in the Arab world is intertwined and shaped by the prevailing socioeconomic and health indicators in the different countries. It also is the story of hard-working pioneers and of human endeavor against adversity, exemplified by 2 of the pioneers having received organ transplants. Arab countries have had more than their fair share of strife and wars, and this has impacted on transplantation services and programs.

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.

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.

Oral health in renal transplant recipients administered cyclosporin A or tacrolimus

OBJECTIVE

The aim of this study was to determine the oral status of renal transplant recipients receiving cyclosporin A (CsA) or tacrolimus (FK-506) as immunosuppressant.

SUBJECTS AND METHODS

A total of 88 renal transplant recipients receiving CsA (63 men and 25 women, mean age 51.4 years) and 67 receiving FK-506 (57 men and 10 women, mean age 33.5 years) were included in the study. Donor type, histocompatibility, cold ischemia time and prior delayed graft function were similar between the two groups. Demographics and pharmacological data were recorded for all subjects.

RESULTS

The results demonstrated that CsA caused a greater number of oral diseases. A greater number of gingival overgrowth was present in patients treated with CsA. However, the combined use with calcium channel blockers increased the gingival overgrowth number. The occurrence of candida in saliva was observed in 80 renal recipients treated with CsA and 20 treated with FK-506. The presence of squamous oral carcinoma (n = 3) and herpes simplex (n = 10) was observed in patients treated with CsA. These alterations were not observed in renal recipients treated with FK-506.

CONCLUSIONS

Renal recipients constitute a high-risk group for oral diseases, as they are immunocompromised. However, the FK-506 regime appears to ameliorate this effect, compared with CsA. Adequate pre- and post-transplant oral health care is recommended for these subjects, irrespective of the time interval for which the drug is administered.

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.

Development of Malignancy Following Living Donor Kidney Transplantation

BACKGROUND

Malignancy following renal transplantation is an important medical problem during the long-term follow-up. We studied some features of the cancers that developed in our patients.

METHODS

We retrospectively reviewed all patients who underwent renal transplantation and developed malignancy from July 1984 to July 2004.

RESULTS

The 2117 patients who underwent living donor kidney transplantation during the 19-year period had a mean follow-up of 81.1 +/- 61 months. During the follow-up, 38 patients (1.8%) developed cancer: 14 Kaposi's sarcomas, 11 lymphoproliferative diseases, four squamous cell carcinomas of the skin, two basal cell carcinomas, one breast, one ovary, one melanoma, one seminoma, one lung, and one ovary. Mean age at transplantation in the malignancy cases was higher than the other recipients (43.5 +/- 12.1 vs 32 +/- 13.9 years) (P = .000). A Kaposi's sarcoma occurred earlier compared with the other cancers (23 +/- 22 vs 62 +/- 44 months P < .05); most of these patients were over 40 years at transplantation (P < .05). We also observed that patients treated with mycophenolate mofetil developed cancer earlier than the others (19 vs 52 months; P = .001). None of the cases with lymphoma had a history of antilymphocytic agent therapy. The 10-year patient survival was 73%.

CONCLUSION

The prevalence of cancer (1.8%) was among the lowest compared with other studies possibly due to implementing a living donor kidney transplantation program that required a low frequency of induction therapy.

Increased seroprevalence of human herpes virus-8 in renal transplant recipients in Saudi Arabia

BACKGROUND

Human herpes virus-8 (HHV-8) is a herpes virus that is always associated with Kaposi's sarcoma. Previous studies suggested a high rate of Kaposi's sarcoma in renal transplant patients in Saudi Arabia. The aim of this study was to investigate the prevalence of HHV-8 in Saudi renal transplant recipients and healthy controls.

METHODS

An immunofluorescence technique was used to detect antibodies to the latent nuclear antigen (LANA) of HHV-8 in renal transplant patients, members of a family affected with Kaposi sarcoma, as well as healthy controls.

RESULTS

A significantly higher HHV-8 seroprevalence was detected in renal transplant recipients from Saudi Arabia (27 out of 150; 18%) and in members of a family affected with Kaposi sarcoma (seven out of 10; 70%) relative to the seroprevalence in healthy controls (10 out of 577; 1.7%). Seropositivity for HHV-8 in these transplant patients was not significantly influenced by: the existence of relatives with kidney failure, the donors' country of origin, the recipients' home region within Saudi Arabia, the haemodialysis centre, the time that elapsed since the renal transplantation operation and the immunosuppressive regimen used.

CONCLUSION

The present results provide some explanation for the previously noted high incidence of Kaposi's sarcoma in Saudi transplant patients.

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.

Kaposi's sarcoma: An update

While there have been many important advances in the study of Kaposi's sarcoma (KS), it remains both a challenge and an enigma in many ways. Kaposi's original description of "multiple idiopathic hemorrhagic sarcoma[s]" in patients who died within 2-3 years resembles KS in AIDS more than classic KS in elderly men of Italian, Jewish, or Mediterranean lineage, in whom the disease is usually benign. KS had been evident in about one-third of those with early AIDS, often as its presenting sign, a pattern markedly reduced in recent times since the introduction of highly active anti-retroviral therapy (HAART). The most important advance has been the convincing etiologic linkage of KS with human herpesvirus 8 (HHV-8), which is necessary but not sufficient. It has a low prevalence in the general population of the USA and UK, with an intermediate rate in Italy and Greece, and a high one in Uganda. KS risk may be significantly lower in AIDS patients with a history of anti-herpes therapy. Many aspects of HHV-8, including its transmission pattern and different genospecies, are being scrutinized. The diagnosis of KS may be difficult. One should be aware of KS clinical variants, including telangiectatic, eccymotic, and keloidal KS. One must consider a number of other disorders, including bacillary angiomatosis. HHV-8 DNA sequences in dermatofibromas and other tumors should probably not be viewed as representing a marker for KS. Therapeutic options vary for KS. Intralesional and low-dose outpatient intravenous vinblastine may be valuable, as immunosuppression with KS is not a good idea if it can be avoided. Anti-herpes virus therapy may have potential for wide use, especially in preventing the development of KS in at risk populations, such as HHV-8 seropositive individuals undergoing transplantation surgery.

Clinical features and course of Kaposi's sarcoma in Egyptian kidney transplant recipients

The prevalence of Kaposi's sarcoma (KS) after renal transplantation varies greatly depending on geographic and ethnic backgrounds. Out of 1400 live-donor kidney transplantation, 50 patients developed malignancy in our center. Kaposi's sarcoma was diagnosed in 24 patients (48%). Twenty patients were males and the main age of the patients was 29.8 +/- 11.1 years. They developed KS at a mean interval of 33.9 +/- 27.2 months, and the main duration of follow up was 62.2 +/- 50.7 months. Nineteen patients were cyclosporinee treated while four patients were azathioprine-based. Cutaneous KS was diagnosed in 20 patients, visceral in one, and three patients had both lesions. We found that the frequency of HLA-A1, -A2 and -DR5 were significantly common in KS patients. Titrated reduction of immunosuppression was initially tried in all patients. Bleomycin injection and superficial irradiation was tried in some cases. Response to therapeutic modalities was good in cutaneous form of KS. Twelve patients died (50%), two of them with functioning graft. We conclude that KS is the most common malignancy after kidney transplantation in our locality. Patients on cyclosporine are more prone to develop KS, and certain HLA-antigens may predispose to this. Early diagnosis and interference carry a favorable outcome.

Molecular genetics of Kaposi's sarcoma-associated herpesvirus (human herpesvirus-8) epidemiology and pathogenesis

Kaposi's sarcoma had been recognized as unique human cancer for a century before it manifested as an AIDS-defining illness with a suspected infectious etiology. The discovery of Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus-8, in 1994 by using representational difference analysis, a subtractive method previously employed for cloning differences in human genomic DNA, was a fitting harbinger for the powerful bioinformatic approaches since employed to understand its pathogenesis in KS. Indeed, the discovery of KSHV was rapidly followed by publication of its complete sequence, which revealed that the virus had coopted a wide armamentarium of human genes; in the short time since then, the functions of many of these viral gene variants in cell growth control, signaling apoptosis, angiogenesis, and immunomodulation have been characterized. This critical literature review explores the pathogenic potential of these genes within the framework of current knowledge of the basic herpesvirology of KSHV, including the relationships between viral genotypic variation and the four clinicoepidemiologic forms of Kaposi's sarcoma, current viral detection methods and their utility, primary infection by KSHV, tissue culture and animal models of latent- and lytic-cycle gene expression and pathogenesis, and viral reactivation from latency. Recent advances in models of de novo endothelial infection, microarray analyses of the host response to infection, receptor identification, and cloning of full-length, infectious KSHV genomic DNA promise to reveal key molecular mechanisms of the candidate pathogeneic genes when expressed in the context of viral infection.

Human herpesvirus 8 seroprevalence in an STD clinic in Paris: a study of 512 patients

BACKGROUND

Human herpesvirus 8 (HHV-8) is thought to be possibly sexually transmitted in some populations, but few data are available on this mode of transmission. GOAL The goal was to study HHV-8 seroprevalence in patients attending a sexually transmitted disease (STD) clinic and to search for predictive factors of HHV-8 seropositivity.

STUDY DESIGN

Five hundred twelve consecutive patients attending the STD clinic of Hôpital Saint-Louis (Paris) were tested for HHV-8 antibodies (immunofluorescence assay using two cell lines, BCP-1 and ISI n. butyrate [3 mmol/l]). A standardized questionnaire was used to obtain demographic, behavioral, and clinical data. Predictive factors of HHV-8 seropositivity were considered in univariate and multivariate analysis with use of logistic regression models.

RESULTS

In testing of the patients for HHV-8 antibodies, 67/512 (13.1%) tested positive: 53/346 (15.3%) of men and 14/166 (8.4%) of women ( = 0.03). The predictive factors of HHV-8 seropositivity for men were the country of origin (Central Africa, odds ratio [OR]: 7.5; North Africa, OR: 5.5), homosexuality (OR: 3.7), and visiting prostitutes (OR: 7.1). For women they were country of origin (Central Africa, OR: 8.3) and presence of HSV-2 antibodies (OR: 6.5, tendency).

CONCLUSION

Our study does not show clear relationships between HHV-8 seropositivity and sexual behavior, apart from homosexuality, but visiting prostitutes (for men) and HSV-2 seropositivity (for women) could be subtle clues supporting the hypothesis of heterosexual transmission.

Spectrum of Kaposi's sarcoma-associated herpesvirus, or human herpesvirus 8, diseases

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), discovered in 1994, is a human rhadinovirus (gamma-2 herpesvirus). Unlike other human herpesviruses (herpes simplex virus, Epstein-Barr virus, varicella-zoster virus, cytomegalovirus, HHV-6, and HHV-7), it is not widespread in the general population and has many unique proteins. HHV-8 is strongly associated with all subtypes of Kaposi's sarcoma (KS), multicentric Castleman's disease, and a rare form of B-cell lymphoma, primary effusion lymphoma. In addition, HHV-8 DNA sequences have been found in association with other diseases, but the role of the virus in these diseases is largely unconfirmed and remains controversial. The seroprevalence of HHV-8, based on detection of latent and lytic proteins, is 2 to 5% in healthy donors except in certain geographic areas where the virus is endemic, 80 to 95% in classic KS patients, and 40 to 50% in HIV-1 patients without KS. This virus can be transmitted both sexually and through body fluids (e.g., saliva and blood). HHV-8 is a transforming virus, as evidenced by its presence in human malignancies, by the in vitro transforming properties of several of its viral genes, and by its ability to transform some primary cells in culture. It is not, however, sufficient for transformation, and other cofactors such as immunosuppressive cytokines are involved in the development of HHV-8-associated malignancies. In this article, we review the biology, molecular virology, epidemiology, transmission, detection methods, pathogenesis, and antiviral therapy of this newly discovered human herpesvirus.

Human herpesvirus type 8 infections among solid organ transplant recipients

Human herpes virus 8 (HHV-8) is known to be associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL) and a form of Castleman's disease. Recently, it has also been shown to be associated with acute bone marrow failure in transplant patients. While, the full spectrum of clinical manifestations due to HHV-8 is yet to be defined in transplant recipients, it is known to cause post-transplant KS as a result of primary as well as secondary infection. This review will discuss the possible role of HHV-8 as a cause of disease in solid organ transplant recipients by focussing on important issues, including the biology of the virus, epidemiology, clinical manifestations, laboratory diagnosis and treatment, followed by a discussion of issues of relevance to the pediatric transplant recipient.

Infectious disease prophylaxis in renal transplant patients: a survey of US transplant centers

Definitive approaches to most infectious diseases following renal transplantation have not been established, leading to different approaches at different transplant centers. To study the extent of these differences, we conducted a survey of the practices surrounding specific infectious diseases at US renal transplant centers. A survey containing 103 questions covering viral, bacterial, mycobacterial and protozoal infections was developed. Surveys were sent to program directors at all U.S. renal transplant centers. Responses were received from 147 of 245 (60%) transplant centers and were proportionately represented all centers with respect to program size and geographical location. Pre-transplant donor and recipient screening for hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV) and cytomegalovirus (CMV) is uniform, but great discrepancy exists in the testing for other agents. HCV seropositive donors are used in 49% of centers. HIV seropositivity remains a contraindication to transplantation, although 13% of centers indicated they have experience with such patients. Post-transplant, there is wide variety in approach to CMV and Pneumocystis carinii (PCP) prophylaxis. Similarly divergent practices affect post-transplant vaccinations, with 54% of centers routinely vaccinating all patients according to customary guidelines in non-transplant populations. In contrast, 22% of centers indicated they do not recommend vaccination in any patients. We believe an appreciation of the differences in approaches to post-transplant infectious complications may encourage individual centers to analyse the results of their own practices. Such analysis may assist in the design of studies to answer widespread and important questions regarding the care of patients following renal transplantation.

Human herpesvirus-8 and Kaposi's sarcoma: relationship with the multistep concept of tumorigenesis

Kaposi's sarcoma (KS) develops through discrete inflammatory-angiogenic stages of polyclonal nature (early-stage lesions) to monomorphic nodules of spindle-shaped cells that can be clonal (late-stage lesions) and resemble true sarcomas. Molecular and epidemiological studies indicate that development of KS is tightly associated with infection by the human herpesvirus-8 (HHV-8). However, only individuals with specific conditions of immunodysregulation develop KS. In these individuals the systemic and tissue increase of Th-1-type cytokines (IC) reactivate HHV-8 infection, leading to increased viral load, antibody titers, and an expanded cell tropism that precedes the clinical appearance of KS. Recruitment of the virus into tissues by infected monocytes and other cell types is facilitated by the endothelial cell activation due to IC. In clinical lesions, HHV-8 infection increases with lesion stage and in late-stage lesions most of the spindle cells are latently infected, whereas only few lyrically infected cells are present, suggesting that latent genes may have a role in the transformation of the early inflammatory-hyperplastic lesion into a real sarcoma. The development of tumors, however, is regulated through a multistep process based on the acquisition by cells of several different capabilities leading to malignant growth. Here we review the available data on the expression of HHV-8-encoded genes in primary KS lesions and, in view of their biological activity, analyze their potential function in different steps of tumorigenesis. By this pragmatic approach interesting insights into potential key functions of HHV-8-encoded genes are found and steps of potential cooperativity with other viral factors (HIV-1-Tat) in the pathogenesis of KS are identified.

Prevalence of antibodies to human herpesvirus 8 (HHV-8) in Saudi Arabian patients with and without renal failure

BACKGROUND

Kaposi's sarcoma (KS) is the most common cancer occurring in renal transplant recipients in Saudi Arabia, where the reported incidence of posttransplantation KS is 10 times higher than the incidence in the United States and Western Europe. The reason for the particularly high incidence of posttransplantation KS in this geographic area is unknown.

METHODS

To explore the possibility that the high incidence of posttransplantation KS might be the result of widespread infection with human herpesvirus 8 (HHV-8), we determined the prevalence of antibodies to HHV-8 in 201 patients with end-stage renal disease (ESRD) and a comparison group of 358 individuals without renal disease who were similar in age, sex, and area of residence. Antibodies to lytic cycle antigens of HHV-8 were determined by indirect immunofluorescence and confirmed by immunoblots using tetradecanoyl phorbol ester acetate-induced BC-3 cell extracts and recombinant small viral capsid antigen (ORF65).

RESULTS

Antibodies to HHV-8 were detected in serum samples from 14 (6.97%) of 201 ESRD patients and from 10 (3.88%) of 258 in the comparison group (P=0.14). HHV-8 seropositive individuals were on average 10 years older than seronegative subjects (55.3 years vs. 46.9 years). Among HHV-8 seropositive subjects, 71% were male and 29% were female.

CONCLUSIONS

Serologic evidence of HHV-8 infection was numerically more common in men and in patients with ESRD. However, among patients with and without ESRD, the strongest association was with increasing age.

Kaposi's sarcoma associated with previous human herpesvirus 8 infection in kidney transplant recipients

This study investigates the prevalence of human herpesvirus 8 (HHV-8) infection in kidney transplant patients, evaluating the risk of HHV-8 transmission via transplantation and the association between pre- and posttransplantation HHV-8 infection and the subsequent development of Kaposi's sarcoma (KS). Immunofluorescence and an enzyme immunoassay were used to determine HHV-8 seroprevalence in 175 patients awaiting kidney transplantation and 215 controls who were attending our clinic for other reasons. All patients in the study came from central or southern Italy. Seroprevalence was similar in both groups (14.8 versus 14.9%), with no significant difference between the rates for male and female patients. Of the 175 patients, 100 were tested for anti-HHV-8 antibodies at various times during follow-up. During follow-up, seroprevalence increased from 12% on the date of transplantation to 26%. This increase was paralleled by an age-related increase in seroprevalence in the control group. During follow-up from 3 months to 10 years after transplantation, KS was diagnosed in seven patients (4.0%). Six of these patients were positive for HHV-8 prior to transplantation. Overall, 23.0% of patients who were HHV-8 positive before transplantation developed KS, whereas only 0.7% of seronegative patients developed the disease (relative risk, 34.4; 95% confidence interval, 4.31 to 274.0). This finding suggests that the key risk factor for KS is infection prior to transplantation and that antibody detection in patients awaiting transplantation could be useful in identifying patients at high risk for KS. In patients from geographic areas with a high prevalence of HHV-8, serological tests on donors may be less important.