Risk factors for Kaposi's sarcoma among HIV-positive individuals in a case control study in Cameroon

Kaposi Sarcoma in People Living with HIV: Is it Water under the Bridge?

Kaposi Sarcoma (KS) is still common among people living with HIV (PLWH). A lot of literature illustrated risk factors associated with KS occurrence, while the aim of our study is to investigate possible factors influencing 5-year survival.  

Systematic analysis of Kaposi's sarcoma (KS)-associated herpesvirus genomes from a KS case-control study in Cameroon: Evidence of dual infections but no association between viral sequence variation and KS risk

In sub-Saharan Africa, Kaposi's sarcoma-associated herpesvirus (KSHV) is endemic, and Kaposi's sarcoma (KS) is a significant public health problem. Until recently, KSHV genotype analysis was performed using variable gene regions, representing a small fraction of the genome, and thus the contribution of sequence variation to viral transmission or pathogenesis are understudied. We performed near full-length KSHV genome sequence analysis on samples from 43 individuals selected from a large Cameroonian KS case-control study. KSHV genomes were obtained from 21 KS patients and 22 control participants. Phylogenetic analysis of the K1 region indicated the majority of sequences were A5 or B1 subtypes and all three K15 alleles were represented. Unique polymorphisms in the KSHV genome were observed including large gene deletions. We found evidence of multiple distinct KSHV genotypes in three individuals. Additionally, our analyses indicate that recombination is prevalent suggesting that multiple KSHV infections may not be uncommon overall. Most importantly, a detailed analysis of KSHV genomes from KS patients and control participants did not find a correlation between viral sequence variations and disease. Our study is the first to systematically compare near full-length KSHV genome sequences between KS cases and controls in the same endemic region to identify possible sequence variations associated with disease risk.

Molecular Epidemiology of Human Herpes Virus Type 8 Among Patients with Compromised Immune System in Ouagadougou, Burkina Faso

Introduction

Human herpesvirus type 8 (HHV-8) is the main etiological agent of Kaposi's sarcoma. This virus is frequently associated with immunocompromision. This study aimed to detect HHV-8 in people with compromised immune system.

Patients and Methods

This is a cross-sectional study that included 180 subjects: 179 HIV-infected patients and 1 patient with bullous pemphigoid. Blood samples were taken from all subjects, and swabs of lesions were then taken from individuals with symptoms of Kaposi's sarcoma. Viral load and CD4+ T lymphocytes count were performed for persons living with HIV and real-time PCR detection of HHV-8 DNA was performed in all subjects in the study.

Results

Among HIV-infected persons, 13.41% had a viral load of more than 10,000 copies/mL, and 22.91% had a CD4+ T lymphocytes count of fewer than 350 cells/µL. A total of four (three HIV-1 infected patients and one patient with bullous pemphigoid) patients (2.22%) had apparent lesions of Kaposi's sarcoma. In the plasmas and swabs from associated lesions, HHV-8 DNA was found in only two individuals, with an HHV-8 prevalence of 1.11% (2/180) with 0.55% (1/179) in an HIV-infected patient on antiretroviral therapy.

Conclusion

These results exposing low prevalence levels of HHV-8 in HIV-infected patients could be due to the beneficial effect of antiretroviral drugs.

Seroprevalence and molecular diversity of Human Herpesvirus 8 among people living with HIV in Brazzaville, Congo

Human herpesvirus 8 (HHV8) is endemic in Africa, although studies of this infection are rare in Congo. We evaluated seroprevalence and HHV-8 diversity among people living with HIV. We included 353 patients receiving highly active antiretroviral therapy. Antibodies against HHV-8 latency-associated nuclear antigen were detected by indirect immunofluorescence. In HHV-8 positive patients, we performed HHV-8 quantification in blood and saliva by real-time PCR and typing by Sanger sequencing of K1 open reading frame. HHV-8 seroprevalence was 19%, being male (odd ratio [OR] = 1.741, [95% Confidence interval {CI}, 0.97-3.07]; p = 0.0581) and having multiple sex partners before HIV diagnosis (OR = 1.682, [CI 95%, 0.97-2.92]; p = 0.0629) tended to be associated with HHV-8 seropositivity. Of the 64 HHV-8 seropositive patients, HHV-8 DNA was detected in 10 (16%) in saliva, 6 (9%) in whole-blood and in 2 (3%) in both whole-blood and saliva. Three out of 6 HHV-8 strains were subtypes A5, 2 subtype B1 and 1 subtype C. HHV-8 seroprevalence was relatively low with more frequent carriage in men, associated with asymptomatic oral excretion and a predominance of subtype A5. These data tend to support the hypothesis of horizontal transmission in people living with HIV in Brazzaville.

Malaria Is Associated With Kaposi Sarcoma-Associated Herpesvirus Seroconversion in a Cohort of Western Kenyan Children

BACKGROUND

We aimed to determine whether Plasmodium falciparum infection affects age of Kaposi sarcoma-associated herpesvirus (KSHV) seroconversion in Kenyan children.

METHODS

Kenyan children (n = 144) enrolled at age 1 month, from 2 sites with different levels of malaria transmission (stable/high vs unstable/low) were followed to age 24 months. Plasma was tested for KSHV antibodies using enzyme-linked immunosorbent assay (ELISA; K8.1 and LANA) and a multiplex bead-based assay (K8.1, K10.5, ORF38, ORF50, and LANA) and whole blood tested for P. falciparum DNA using quantitative PCR. Cox proportional hazards models were used to assess associations between P. falciparum DNA detection, malaria annualized rate (P. falciparum detections/person-years), and enrollment site (malaria-high vs malaria-low) with time to KSHV seroconversion.

RESULTS

KSHV seroprevalence was 63% by age 2 years when assessed by multiplex assay. Children with P. falciparum were at increased hazards of earlier KSHV seroconversion and, among children with malaria, the hazard of becoming KSHV seropositive increased significantly with increasing malaria annualized rate. Children from the malaria-high transmission region had no significant difference in hazards of KSHV seroconversion at 12 months but were more likely to become KSHV seropositive by age 24 months.

DISCUSSION

Malaria exposure increases the risk for KSHV seroconversion early in life.

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.

Malaria during pregnancy and transplacental transfer of Kaposi sarcoma-associated herpesvirus (KSHV) antibodies: a cohort study of Kenyan mother and child pairs

BACKGROUND

Kaposi sarcoma-associated herpesvirus (KSHV) seroprevalence in sub-Saharan African children can range up to 50% by age 2 years but factors affecting early age of KSHV infection are not well understood. Malaria during pregnancy has been associated with hindered transplacental transfer of antibodies to several pathogens but whether it affects transplacental transfer of KSHV antibodies is unknown. We aimed to determine if in utero malaria exposure reduced the transfer of KSHV antibodies across the placenta.

METHODS

A cohort study in Kisumu, Kenya enrolled pregnant women at their first antenatal clinic (ANC) visit and followed them through delivery. We included 70 KSHV-positive, HIV-negative mothers and their children. KSHV antibody levels were measured by ELISA (K8.1, ORF73) and multiplex assay (K8.1, ORF73, K10.5, ORF38, ORF50). Transplacental transfer of antibodies was measured by the cord to maternal blood ratio (CMR) of KSHV antibodies. Malaria during pregnancy was defined as detection of Plasmodium falciparum (Pf) DNA at any ANC visit or delivery. Among women with malaria during pregnancy, we examined time of last malaria infection prior to delivery (< 27 vs. 27+ weeks gestation) and malaria incidence rate (MIR) (episodes/100 person-weeks).

RESULTS

KSHV seroprevalence (positive for K8.1 or ORF73 by ELISA) among pregnant women was 88%. Neither malaria during pregnancy, malaria infection timing, nor MIR were associated with maternal delivery KSHV antibody blood levels. Maternal delivery and cord blood KSHV antibody levels were highly correlated but these correlations did not differ by malaria during pregnancy. KSHV transplacental antibody transfer was not associated with malaria during pregnancy, malaria infection timing, nor MIR.

CONCLUSIONS

Malaria during pregnancy does not appear to affect transfer of KSHV antibodies across the placenta.

Kaposi's sarcoma-associated herpesvirus protein ORF75 among HIV-1 patients in Kenya

Background

Histology is used to identify Kaposi’s sarcoma (KS) in countries with low resources to fund healthcare costs. Approximately 95% of KS cases can be detected using a polymerase chain reaction.

Objective

To determine the presence of the open reading frame 75 (ORF75) gene associated with Kaposi’s sarcoma herpes virus among HIV-1/AIDS patients and to describe morphological presentations of KS.

Methods

This was a retrospective, descriptive study of archived tissue blocks collected from 2013 to 2016. Haematoxylin and eosin staining was used to identify KS. Deoxyribonucleic acid from archived tissue blocks was extracted and a nested polymerase chain reaction was used to detect the ORF75 gene.

Results

All 81 cases in this study had been diagnosed as HIV-1 positive, of which 68 had hallmark features of KS in the histology report and 13 had features suggestive of KS (‘KS-like’). Microscopic identification of KS by haematoxylin and eosin staining was considered a significant indicator of KS herpes virus ORF75 gene positivity (p = 0.002). The ORF75 gene was detected in 60.5% (49/81) of tissue blocks; 27.2% were men (22/81) and 33.3% were women (27/81). The ORF75 gene was observed to be present in up to 15.4% (2/13) of the cases reported to have KS-like features.

Conclusion

Following the initial diagnosis of KS by histology, the ORF75 gene was fur-ther detected from both cases that had hallmark features of KS as well as among cases with KS-like fea-tures.

Dual infection and recombination of Kaposi sarcoma herpesvirus revealed by whole-genome sequence analysis of effusion samples

Kaposi sarcoma herpesvirus (KSHV) is the etiological agent of three malignancies, Kaposi sarcoma (KS), primary effusion lymphoma (PEL) and KSHV-associated multicentric Castelman disease. KSHV infected patients may also have an interleukin six-related KSHV-associated inflammatory cytokine syndrome. KSHV-associated diseases occur in only a minority of chronically KSHV-infected individuals and often in the setting of immunosuppression. Mechanisms by which KSHV genomic variations and systemic co-infections may affect the pathogenic pathways potentially leading to these diseases have not been well characterized in vivo. To date, the majority of comparative genetic analyses of KSHV have been focused on a few regions scattered across the viral genome. We used next-generation sequencing techniques to investigate the taxonomic groupings of viruses from malignant effusion samples from fourteen participants with advanced KSHV-related malignancies, including twelve with PEL and two with KS and elevated KSHV viral load in effusions. The genomic diversity and evolutionary characteristics of nine isolated, near full-length KSHV genomes revealed extensive evidence of mosaic patterns across all these genomes. Further, our comprehensive NGS analysis allowed the identification of two distinct KSHV genome sequences in one individual, consistent with a dual infection. Overall, our results provide significant evidence for the contribution of KSHV phylogenomics to the origin of KSHV subtypes. This report points to a wider scope of studies to establish genome-wide patterns of sequence diversity and define the possible pathogenic role of sequence variations in KSHV-infected individuals.

Epidemic, Endemic, or Stewart-Bluefarb? When Several Forms of Kaposi Seem to Dispute Paternity

The role of human herpes virus 8 (HHV8) is demonstrated in the occurrence of Kaposi's disease, but the role of cofactors is still hardly known. We report a case of Kaposi's disease which occurred 10 years after a local trauma in an HIV-positive patient from Central Africa. A 38-year-old female, from and living in Central Africa, consulted for angiomatous papulo-nodules associated with purple-colored macules and painful lymphoedema of the right leg and foot that had been developing for 6 months. She reported a history of posttraumatic lymphoedema of the affected limb as a result of a road accident that occurred ten years earlier. The mucous were healthy. There was no sign of systemic lesions. The diagnosis of Kaposi's disease was evoked with, in differential, a Stewart–Bluefarb syndrome-type of pseudo-Kaposi and an epidemic Kaposi disease. Retroviral serology was positive to HIV1 with a CD4 count of 600 cells/mm³. Histopathology of the lesions and duplex ultrasonography could not be performed. The rest of the biological assessment was without particularity. The diagnosis of epidemic Kaposi's disease associated with cofactors involved in endemic Kaposi's disease and Stewart–Bluefarb syndrome was retained. An antiretroviral treatment (emtricitabine, tenofovir, and efavirenz) allowed to obtain after 6 months a noticeable improvement of the lesions and a disappearance of the pain with however the persistence of a residual lymphoedema. This is a special case of Kaposi's disease that seems to involve several factors. The role of cofactors in Kaposi's disease remains to be elucidated.

[Kaposi sarcoma combined with severe ulcerative colitis: A case report and literature review]

Kaposi's sarcoma (KS) is an unusual vascular tumor associated with human herpesvirus-8 (HHV-8) infection, which is common in immunosuppressors. Although extremely rare, iatrogenic (drug-related) KS can occur in human immunodeficiency virus (HIV)-negative patients under immunosuppressive therapy. We report a 64-year-old male diagnosed with ulcerative colitis for 1 year. He was treated with methylprednisolone because of an acute severe disease flare. He presented with several popular violet lesions on the body 4 months after steroid therapy. Histological examination of skin biopsies showed Kaposi's sarcoma associated with HHV-8. The skin lesions regressed after steroid withdrawal and chemotherapy. Two key words "Kaposi's sarcoma" and "inflammatory bowel disease" were searched in Wanfang data and CNKI, but no relevant articles were found. Thirty-eight articles in English were retrieved on PubMed with the key words of ("ulcerative colitis" OR "Crohn's disease" OR "inflammatory bowel disease") AND (Kaposi sarcoma). Twenty-five cases of Kaposi's sarcoma related to inflammatory bowel disease (IBD) were reported. Including this case, the majority of 26 Kaposi's sarcoma related IBD patients were male (80.8%, 21/26). The average age was (51.1 ± 16.4) years. Twenty cases were ulcerative colitis and 6 were Crohn's disease. All the patients received immunomodulatory therapy, including glucocorticoid, azathioprine/mercaptopurine, methotrexate, cyclosporin and anti tumor necrosis factor α antibody. Thirteen cases were positive for HHV-8. There were 18 cases involving the distal ileum and colorectum only, 3 cases involving skin only, and 5 cases involving both skin and colorectum at the same time. Overall, the prognosis was good. Three patients only stopped immunosuppressive therapy, 1 received radiotherapy, 1 received chemotherapy, and 20 received surgery. Kaposi's sarcoma could be seen in IBD patients with immunomodulatory therapy. It is very important to distinguish from the skin lesions related to IBD or drug treatment. The adverse reactions of immunomodulatory therapy should not be ignored. In addition, attention should be paid to the cooperation of multi-disciplinary team, which can diagnose and treat rare cases earlier and more accurately.

Relationship between human leukocyte antigen alleles and risk of Kaposi's sarcoma in Cameroon

Several studies published to date report associations between human leukocyte antigen (HLA) alleles and different types of Kaposi's Sarcoma (KS). However, there is little concordance between the HLA alleles identified and the populations studied. To test whether HLA alleles associate with KS in a Cameroonian case-control study, we performed high-resolution HLA typing in KSHV seropositive individuals. Among HIV-positive individuals, carriers of HLA-B*14:01 were at a significantly higher risk of AIDS-KS (p = 0.033). For HIV-negative patients, a gene-wise comparison of allele frequencies identified the HLA-B (p = 0.008) and -DQA1 (p = 0.002) loci as possible risk factors for endemic KS. Our study provides additional understanding of genetic determinants of KS and their implications in disease pathogenesis. Further validation of these findings is needed to define the functional relevance of these associations.

Mutual detection of Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus in blood and saliva of Cameroonians with and without Kaposi's sarcoma

Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV) are prevalent in sub-Saharan Africa, together with HIV; the consequent burden of disease is grave. The cofactors driving transmission of the two viruses and pathogenesis of associated malignancies are not well understood. We measured KSHV and EBV DNA in whole blood and saliva as well as serum antibodies levels in 175 Cameroonians with Kaposi's sarcoma and 1,002 age- and sex-matched controls with and without HIV. KSHV seroprevalence was very high (81%) in controls, while EBV seroprevalence was 100% overall. KSHV DNA was detectable in the blood of 36-46% of cases and 6-12% of controls; EBV DNA was detected in most participants (72-89%). In saliva, more cases (50-58%) than controls (25-28%) shed KSHV, regardless of HIV infection. EBV shedding was common (75-100%); more HIV+ than HIV- controls shed EBV. Cases had higher KSHV and EBV VL in blood and saliva then controls, only among HIV+ participants. KSHV and EBV VL were also higher in HIV+ than in HIV- controls. Cases (but not controls) were more likely to have detectable KSHV in blood if they also had EBV, whereas shedding of each virus in saliva was independent. While EBV VL in saliva and blood were modestly correlated, no correlation existed for KSHV. Numerous factors, several related to parasitic coinfections, were associated with detection of either virus or with VL. These findings may help better understand the interplay between the two gammaherpesviruses and generally among copathogens contributing to cancer burden in sub-Saharan Africa.

Kaposi sarcoma

Kaposi sarcoma (KS) gained public attention as an AIDS-defining malignancy; its appearance on the skin was a highly stigmatizing sign of HIV infection during the height of the AIDS epidemic. The widespread introduction of effective antiretrovirals to control HIV by restoring immunocompetence reduced the prevalence of AIDS-related KS, although KS does occur in individuals with well-controlled HIV infection. KS also presents in individuals without HIV infection in older men (classic KS), in sub-Saharan Africa (endemic KS) and in transplant recipients (iatrogenic KS). The aetiologic agent of KS is KS herpesvirus (KSHV; also known as human herpesvirus-8), and viral proteins can induce KS-associated cellular changes that enable the virus to evade the host immune system and allow the infected cell to survive and proliferate despite viral infection. Currently, most cases of KS occur in sub-Saharan Africa, where KSHV infection is prevalent owing to transmission by saliva in childhood compounded by the ongoing AIDS epidemic. Treatment for early AIDS-related KS in previously untreated patients should start with the control of HIV with antiretrovirals, which frequently results in KS regression. In advanced-stage KS, chemotherapy with pegylated liposomal doxorubicin or paclitaxel is the most common treatment, although it is seldom curative. In sub-Saharan Africa, KS continues to have a poor prognosis. Newer treatments for KS based on the mechanisms of its pathogenesis are being explored.

Prevalence and associated risk factors for Kaposi's sarcoma among HIV-positive patients in a referral hospital in Northern Tanzania: a retrospective hospital-based study

Background

Kaposi’s sarcoma (KS) is a multifocal angioproliferative tumor involving blood and lymphatic vessels, caused by Human Herpes Virus-8 (HHV-8). KS is an important AIDS-defining tumor with high prevalence in Sub-Saharan Africa, including Tanzania which has high HIV and HHV-8 sero-prevalence. It is critically important to monitor the prevalence of AIDS-defining tumors, such as KS, in the age of HIV/AIDS. We studied the prevalence of KS and associated risk factors among HIV-positive patients at Kilimanjaro Christian Medical Centre (KCMC), a referral hospital in northern Tanzania, over the period from January 2012 to December 2015.

Methods

This was a retrospective hospital-based cross-sectional study to determine the prevalence of KS among HIV/AIDS patients between 2012 and 2015. The study included 1100 HIV patients’ data which were collected at the Infectious Disease Clinic (IDC) from patients’ files. Stata version 13 (StataCorp LP, Texas 77,845 USA) was used for all statistical analyses. The prevalence of KS was calculated across levels of a number of categorical variables. Logistic regression was performed to determine relative risk of KS for all characteristics. We included all variables with p-values ≤10% in the multivariate analysis, including ART use, as this is considered to have an influence on KS. In the multivariate analysis, statistical significance was established based on a two-tailed p-value ≤5%. All patients’ notes were kept confidential as per the Helsinki declaration.

Results

Our results revealed a 4.6% prevalence of KS at KCMC hospital, between January 2012 and December 2015, 51(4.6%) patients were diagnosed with KS out of 1100 HIV-positive patients. The study further revealed that KS in HIV patients was most associated with low CD4 cell count (less than or equal to 200 cells/μl). Moreover, women were more likely than men to diagnosed with KS, with higher odds significantly associated with KS (OR 0.42, p < 0.009). Increased age, above 35 years, among the HIV seropositive patients was significantly associated with KS (OR 25.67, p < 0.007). HIV patients who were none smokers were more likely to suffer from KS compared to HIV smokers (OR 0.41, p < 0.010).

Conclusion

KS remains a common malignant vascular tumor commonly associated with HIV/AIDS in Tanzania. Our study highlights the need for continued efforts to combat HIV, as well as associated diseases such as KS. Continued availability of ART (Anti-Retroviral Therapy) to HIV/AIDS patients, and test reagents for CD4 cell count and viral load determination are important measures to alleviate the suffering of these patients. Furthermore, studies to gather more evidence on ART resistance are highly needed to guide treatment choices.

HHV-8 Seroprevalence and Genotype Distribution in Africa, 1998⁻2017: A Systematic Review

Human herpes virus type 8 (HHV-8) is the causative agent of Kaposi's sarcoma (KS). We systematically reviewed literature published between 1998 and 2017, according to the PRISMA guidelines, to understand the distribution of HHV-8 infection in Africa. More than two-thirds (64%) of studies reported on seroprevalence and 29.3% on genotypes; 9.5% were on both seroprevalence and genotypes. About 45% of African countries had data on HHV-8 seroprevalence exclusively, and more than half (53%) had data on either seroprevalence or genotypes. Almost half (47%) of the countries had no data on HHV-8 infection. There was high heterogeneity in the types of tests and interpretation algorithms used in determining HHV-8 seropositivity across the different studies. Generally, seroprevalence ranged from 2.0% in a group of young children in Eritrea to 100% in a small group of individuals with KS in Central African Republic, and in a larger group of individuals with KS in Morocco. Approximately 16% of studies reported on children. Difference in seroprevalence across the African regions was not significant (95% CI, χ² = 0.86; p = 0.35), although specifically a relatively significant level of infection was observed in HIV-infected children. About 38% of the countries had data on K1 genotypes. K1 genotypes A, A5, B, C, F and Z occurred at frequencies of 5.3%, 26.3%, 42.1%, 18.4%, 5.3% and 2.6%, respectively. Twenty-three percent of the countries had data for K15 genotypes, and genotypes P, M and N occurred at frequencies of 52.2%, 39.1%, and 8.7%, respectively. Data on HHV-8 inter-genotype recombinants in Africa are scanty. HHV-8 may be endemic in the entire Africa continent but there is need for a harmonized testing protocol for a better understanding of HHV-8 seropositivity. K1 genotypes A5 and B, and K15 genotypes P and M, from Africa, should be considered in vaccine design efforts.

Was Kaposi's sarcoma-associated herpesvirus introduced into China via the ancient Silk Road? An evolutionary perspective

Kaposi's sarcoma-associated herpesvirus (KSHV) has become widely dispersed worldwide since it was first reported in 1994, but the seroprevalence of KSHV varies geographically. KSHV is relatively ubiquitous in Mediterranean areas and the Xinjiang Uygur Autonomous Region, China. The origin of KSHV has long been puzzling. In the present study, we collected and analysed 154 KSHV ORF-K1 sequences obtained from samples originating from Xinjiang, Italy, Greece, Iran and southern Siberia using Bayesian evolutionary analysis in BEAST to test the hypothesis that KSHV was introduced into Xinjiang via the ancient Silk Road. According to the phylogenetic analysis, 72 sequences were subtype A and 82 subtype C, with C2 (n = 56) being the predominant subtype. The times to the most recent common ancestors (tMRCAs) of KSHV were 29,872 years (95% highest probability density [HPD], 26,851-32,760 years) for all analysed sequences and 2037 years (95% HPD, 1843-2229 years) for Xinjiang sequences in particular. The tMRCA of Xinjiang KSHV was exactly matched with the time period of the ancient Silk Road approximately two thousand years ago. This route began in Chang'an, the capital of the Han dynasty of China, and crossed Central Asia, ending in the Roman Empire. The evolution rate of KSHV was slow, with 3.44 × 10-6 substitutions per site per year (95% HPD, 2.26 × 10-6 to 4.71 × 10-6), although 11 codons were discovered to be under positive selection pressure. The geographic distances from Italy to Iran and Xinjiang are more than 4000 and 7000 kilometres, respectively, but no explicit relationship between genetic distance and geographic distance was detected.

HIV-associated Kaposi sarcoma and related diseases

: The search for the etiologic agent for Kaposi sarcoma led to the discovery of Kaposi sarcoma-associated herpesvirus (KSHV) in 1994. KSHV, also called human herpesvirus-8, has since been shown to be the etiologic agent for several other tumors and diseases, including primary effusion lymphoma (PEL), an extracavitary variant of PEL, KSHV-associated diffuse large B-cell lymphoma, a form of multicentric Castleman disease, and KSHV inflammatory cytokine syndrome. KSHV encodes several genes that interfere with innate and specific immunity, thwart apoptosis, enhance cell proliferation and cytokine production, and promote angiogenesis, and these play important roles in disease pathogenesis. HIV is an important cofactor in Kaposi sarcoma pathogenesis, and widespread use of antiretroviral therapy has reduced Kaposi sarcoma incidence. However, Kaposi sarcoma remains the second most frequent tumor arising in HIV-infected patients in the United States and is particularly common in sub-Saharan Africa. KSHV prevalence varies substantially in different populations. KSHV is secreted in saliva, and public health measures to reduce its spread may help reduce the incidence of KSHV-associated diseases. Although there have been advances in the treatment of Kaposi sarcoma, KSHV-multicentric Castleman disease, and PEL, improved therapies are needed, especially those that are appropriate for Kaposi sarcoma in resource-poor regions.

Speculations on the clinical significance of asymptomatic viral infections

A detailed understanding of asymptomatic chronic viral infections is critical to analyse their pathogenesis, assess the severity and burden of disease and, where required, optimize public health control measures. Recent studies on herpesviruses showed that the host-virus interactions are modulated by co-infections, emphasizing the relevance of co-infections in determining the clinical expression (from asymptomatic to symptomatic infections) and the severity of herpesvirus-associated diseases (either neoplastic or infectious diseases). To demonstrate causality between viruses (virome) and diseases, Koch's postulates should be adapted adding new knowledge on host-microbe relationship and microbial interactions. In the present review we aim to provide an update on asymptomatic chronic infections and criteria for causality and on the virological, immunological and host-virus interactions in asymptomatic chronic infections in human hosts, focusing on herpetic infections.

Co-infections and Pathogenesis of KSHV-Associated Malignancies

Kaposi’s sarcoma-associated herpesvirus (KSHV), also known as human herpes virus 8 (HHV-8) is one of the several carcinogenic viruses that infect humans. KSHV infection has been implicated in the development of Kaposi’s sarcoma (KS), primary effusion lymphoma, and multicentric Castleman’s Disease. While KSHV infection is necessary for the development of KSHV associated malignancies, it is not sufficient to induce tumorigenesis. Evidently, other co-factors are essential for the progression of KSHV induced malignancies. One of the most important co-factors, necessary for the progression of KSHV induced tumors, is immune suppression that frequently arises during co-infection with HIV and also by other immune suppressants. In this mini-review, we discuss the roles of co-infection with HIV and other pathogens on KSHV infection and pathogenesis.

Risk factors for Kaposi's sarcoma in human immunodeficiency virus patients after initiation of antiretroviral therapy: A nested case-control study in Kenya

BACKGROUND/PURPOSE

This study aimed to evaluate the association between highly active antiretroviral therapy (HAART) adherence and development of Kaposi's sarcoma (KS) in human immunodeficiency virus (HIV)/AIDS patients.

METHODS

We conducted a retrospective nested case-control study of 165 participants (33 cases and 132 controls) receiving HAART care at Maseno Hospital, Kenya, from January 2005 to October 2013. Cases were HIV-positive adults with KS, who were matched with controls in a ratio of 1:4 based on age (±5 years of each case), sex, and KS diagnosis date. Perfect adherence to HAART was assessed on every clinic visit by patients' self-reporting and pill counts. Chi-square tests were performed to compare socioeconomic and clinical statuses between cases and controls. A conditional logistic regression was used to assess the effects of perfect adherence to HAART, the latest CD4 count, education level, distance to health-care facility, initial World Health Organization stage, and number of regular sexual partners on the development of KS.

RESULTS

Only 63.6% participants reported perfect adherence, and the control group had a significantly higher percentage of perfect adherence (75.0%) than did cases (18.2%). After adjustment for potential imbalances in the baseline and clinical characteristics, patients with imperfect HAART adherence had 20-times greater risk of developing KS than patients with perfect HAART adherence [hazard ratios: 21.0, 95% confidence interval: 4.2-105.1]. Patients with low latest CD4 count (≤350 cells/mm³) had a seven-times greater risk of developing KS than did their counterparts (HRs: 7.1, 95% CI: 1.4-36.2).

CONCLUSION

Imperfect HAART adherence and low latest CD4 count are significantly associated with KS development.

The clinical characteristics of 80 cases of acquired immunodeficiency syndrome-associated Kaposi's sarcoma in Xinjiang Autonomous Region and the effect of different treatments on the prognosis

To analyze the clinical features of AIDS-related Kaposi's sarcoma (AIDS-KS) patients in Xinjiang Autonomous Region and the impact of CD4 (+)T lymphocyte count, highly active antiretroviral therapy (HAART) and systemic chemotherapy on the prognosis. The clinical information of 80 AIDS-KS patients admitted in Sixth People's Hospital of Xinjiang Autonomous Region from January 2008 to August 2014 was retrospectively reviewed. Population characteristics, extent of lesions, KS progress, CD4 (+)T lymphocyte count, combined opportunistic infections, treatment and prognosis of these patients were analyzed. The 80 patients were divided into five groups according to treatment methods, including HAART, HAART + chemotherapy, chemotherapy + HAART, chemotherapy, and untreated groups. The efficacy and prognosis of the five groups were compared. Among the 80 patients, 74 (92.50%) patients were Uygur. The average age was 39.5±9.9 years and male-to-female ratio was 3:1. The median of baseline CD4 (+)T lymphocyte count was 152.5 cells/μL and the interquartile was 233.25 cells/μL. CD4 (+)T lymphocyte counts were significantly increased after treatment in HAART, HAART + chemotherapy, and chemotherapy + HAART groups (P < 0.05). CD4 (+)T lymphocyte count in chemotherapy groups was significantly reduced after treatment (P < 0.05). The untreated group had the highest mortality rate (33.3%). In HAART group, KS-associated immune reconstitution inflammatory response syndrome (KS-IRIS) appeared in 45.5% cases and 2 death cases were caused by KS-IRIS. In Xinjiang Autonomous Region, the incidence of AIDS-KS is high in young Uygur male people. HAART followed by chemotherapy has ideal efficacy, reduces the incidence of KS-IRIS and improves the prognosis.

Epidemiology and transmission of Kaposi's sarcoma-associated herpesvirus

This review summarizes the current knowledge pertaining to Kaposi sarcoma-associated herpesvirus (KSHV) epidemiology and transmission. Since the identification of KSHV twenty years ago, it is now known to be associated with Kaposi's sarcoma (KS), primary effusion lymphoma, and multicentric Castleman's disease. Many studies have been conducted to understand its epidemiology and pathogenesis and their results clearly show that the worldwide distribution of KSHV is uneven. Some geographical areas, such as sub-Saharan Africa, the Mediterranean region and the Xinjiang region of China, are endemic areas, but Western Europe and United States have a low prevalence in the general population. This makes it imperative to understand the risk factors associated with acquisition of infection. KSHV can be transmitted via sexual contact and non-sexual routes, such as transfusion of contaminated blood and tissues transplants, or via saliva contact. There is now a general consensus that salivary transmission is the main route of transmission, especially in children residing in endemic areas. Therefore, there is a need to better understand the sources of transmission to young children. Additionally, lack of animal models to study transmission, gold standard serological assay and the lack of emphasis on endemic KS research has hampered the efforts to further delineate KSHV transmission in order to design effective prevention strategies.