HLA studies of endemic African Kaposi's sarcoma patients and matched controls: no association with HLA-DR5

Comparative transcriptome analysis of endemic and epidemic Kaposi's sarcoma (KS) lesions and the secondary role of HIV-1 in KS pathogenesis

In sub-Saharan Africa, endemic Kaposi's sarcoma (EnKS) is still prevalent despite high incidence of epidemic Kaposi's sarcoma (EpKS) resulting from the on-going HIV-1 epidemic. While KSHV is clearly the etiologic agent of KS, the mechanisms underlying KS development are not fully understood. For example, HIV-1 co-infection and concomitant immune dysfunction have been associated with EpKS development. However, the direct or indirect role(s) of HIV-1, and therefore of immune suppression, in EpKS remains unclear. How, or whether, EpKS is mechanistically distinct from EnKS is unknown. Thus, the absence of HIV-1 co-infection in EnKS provides a unique control for investigating and deciphering whether HIV-1 plays a direct or indirect role in the EpKS tumor microenvironment. We hypothesized that HIV-1 co-infection would induce transcriptome changes that differentiate EpKS from EnKS, thereby defining the direct intra-tumor role of HIV-1 in KS. Comparison of ART-treated and -naïve patients would further define the impact of ART on the KS transcriptome. We utilized RNA-seq followed by multiparameter bioinformatics analysis to compare transcriptomes from KS lesions to uninvolved control skin. We provide the first transcriptomic comparison of EpKS versus EnKS, ART-treated vs-naïve EpKS and male vs female EpKS to define the roles of HIV-1 co-infection, the impact of ART, and gender on KS gene expression profiles. Our findings suggest that ART-use and gender have minimal impact on transcriptome profiles of KS lesions. Gene expression profiles strongly correlated between EpKS and EnKS patients (Spearman r = 0.83, p<10-10). A subset of genes involved in tumorigenesis and inflammation/immune responses showed higher magnitude, but not unique dysregulation in EnKS compared to EpKS. While gender and ART had no detectable contribution, the trend toward higher magnitude of gene dysregulation in EnKS coupled with the absence of HIV-1 transcripts in EpKS may suggest an indirect or systemic effect of HIV-1 to promote KS tumorigenesis.

Human leukocyte antigen polymorphisms and Kaposi's sarcoma-associated herpesvirus infection outcomes: A call for deeper exploration

Host genetic background may influence the immunity to resist viral infection. As the most polymorphic loci in the entire human genome, the human leukocyte antigen (HLA) system plays an important role in innate and adaptive immune responses to many invading pathogens. Studies have shown that an association might exist between HLA polymorphisms and susceptibility to Kaposi's sarcoma-associated herpesvirus (KSHV) infection and associated diseases. However, discrepant conclusions were reached among different subjects with different detection methods. Therefore, it is now urgent to summarize current results and figure out the achievements and deficiencies of the existing research for the reference to future studies. A better understanding about the role of HLA polymorphisms in KSHV infection outcome would enable us to elucidate the pathways through which the virus evades the host defense system and improve strategies for the prevention and treatment of KSHV infection.

Epidemiology of Classic Kaposi's Sarcoma, with Special Reference to Mediterranean Population

An excess of classic Kaposi's sarcoma (KS) in individuals of southern European ancestry has long been suspected and recently quantified in terms of age-standardized rates. In Italy and most notably in southern Italy for the period 1976-84, prior to the AIDS epidemic, KS incidence rates were two-to-three-fold higher than in the United States and Sweden and many ten-fold higher than in England and Wales and Australia. A high frequency of classic KS has also been documented in Israel and, in low-risk countries, in individuals born in southern Europe and the Middle East. Many infections have been suspected to play a role in the etiology of KS, including cytomegalovirus, malaria and, most recently, a new virus of the herpes family, identified in AIDS-associated and classic KS. The present review deals with epidemiologic data concerning KS in the Mediterranean and stresses the opportunity to combine the study of KS in AIDS as well as non-AIDS patients in order to shed light on this no longer rare disease.

Risk of Classic Kaposi Sarcoma With Combinations of Killer Immunoglobulin-Like Receptor and Human Leukocyte Antigen Loci: A Population-Based Case-control Study

BACKGROUND

Kaposi sarcoma (KS) is a complication of KS-associated herpesvirus (KSHV) infection. Other oncogenic viral infections and malignancies are associated with certain HLA alleles and their natural killer (NK) cell immunoglobulin-like receptor (KIR) ligands. We tested whether HLA-KIR influences the risk of KSHV infection or KS.

METHODS

In population-based case-control studies, we compared HLA class I and KIR gene frequencies in 250 classic (non-AIDS) KS cases, 280 KSHV-seropositive controls, and 576 KSHV-seronegative controls composing discovery and validation cohorts. Logistic regression was used to calculate sex- and age-adjusted odds ratios (ORs) and 95% confidence intervals.

RESULTS

In both the discovery and validation cohorts, KS was associated with HLA-A*11:01 (adjusted OR for the combined cohorts, 0.4; P = .002) and HLA-C*07:01 (adjusted OR, 1.6; P = .002). Consistent associations across cohorts were also observed with activating KIR3DS1 plus HLA-B Bw4-80I and homozygosity for HLA-C group 1. With KIR3DS1 plus HLA-B Bw4-80I, the KSHV seroprevalence was 40% lower (adjusted OR for the combined cohorts, 0.6; P = .01), but the KS risk was 2-fold higher (adjusted OR, 2.1; P = .002). Similarly, the KSHV seroprevalence was 40% lower (adjusted OR, 0.6; P = .01) but the KS risk 80% higher with HLA-C group 1 homozygosity (adjusted OR, 1.8; P = .005).

CONCLUSIONS

KIR-mediated NK cell activation may decrease then risk of KSHV infection but enhance KSHV dissemination and progression to KS if infection occurs.

Role of environmental factors in the pathogenesis of classic and African-endemic Kaposi sarcoma

Kaposi sarcoma (KS) is a mesenchymal tumour associated with human herpesvirus-8 (HHV-8) infection. However, the incidence of HHV-8 infection is far higher than the prevalence of KS, suggesting that viral infection per se is not sufficient for the development of aggressive phenotype and that one or more additional cofactors are required. The great geographical variation in African-endemic and classic KS incidence points to a role for environmental factors in the etiology of Kaposi sarcoma. However, there are few unequivocably established environmental factors involved in KS pathogenesis. This review focuses on the environmental factors thought to be associated with KS, more particularly iron exposure and facilitation of transmission of HHV-8 infection by contact with blood-sucking arthropods.

Kaposi's sarcoma: aetiopathogenesis, histology and clinical features

Kaposi's sarcoma (KS) represents today one of the most common skin cancers in transplanted Mediterranean subjects and, since the epidemic of human immunodeficiency virus/acquired immune deficiency syndrome, in young unmarried single men. The disease has been associated with the recent identified human herpesvirus (HHV)-8 or KS herpesvirus and its incidence in the general population shows a north to south gradient that parallels the HHV-8 increasing prevalence from Nordic countries to sub-Saharan regions. The identification of the aetiopathogenetic mechanisms (viral agents and immunodeficiency) involved in the pathogenesis of KS, are relevant for identifying susceptible subjects (HHV-8 seropositive subjects), monitoring the immune levels in iatrogenic immune suppressed patients, and developing new therapeutic approaches based on antiviral and immune modulators.

LEARNING OBJECTIVE

This article should enable the reader: (i) to learn about the clinical and molecular aspects of KS in order to have a multidisciplinary approach to a tumour that shows unique features; (ii) to consider the role of viral agents and immunity; and (iii) to recognize properties of an opportunistic neoplasm. The identification of the HHV-8 role in KS pathogenesis should establish a relevant tool in the clinical management of KS patients.

Human herpesvirus 8, Kaposi's sarcoma, and associated conditions

HHV-8 is a recently identified human herpes virus that can produce tumors, most often in immune compromised hosts. The virus is most closely associated with Kaposi's sarcoma, but is also clearly associated with primary effusion lymphomas and multicentric Castleman's disease. The prevalence of HHV-8 infection varies considerably, but is highest among men who have sex with men and others with histories of sexually transmitted diseases and high numbers of lifetime sexual partners. HHV-8 is shed in saliva, and less commonly in genital secretions. Treatment of HHV-8 associated diseases includes reversal of immune compromise either via discontinuation of immunosuppressives or immune reconstitution via antiretroviral regimens. Specific antiviral drug inhibit HHV-8 replication, and can result in responses in certain HHV-8-associated conditions.

Kaposi's sarcoma in women: A clinicopathologic study

BACKGROUND

Although all epidemiologic subsets of Kaposi's sarcoma (KS) (i.e., sporadic, endemic, epidemic, and iatrogenic) have an association with human herpes virus 8 (HHV8), these subsets occur in patient populations with distinctive clinical features. To a variable degree men outnumber women in all subsets.

OBJECTIVE

A retrospective study of women with histologically proven cutaneous KS was undertaken to determine the clinical and histopathologic features, as well as any associations.

METHODS

Two hundred and fifty cases of cutaneous KS in women from 1975 to 1993 were reviewed.

RESULTS

Of the patients, 80% were more than 60 years of age, and of the patients less than 60 years old, 28 were from areas of the world with endemic KS. All HIV+ patients but one were from areas of endemic KS. Two patients were renal transplant patients. Sixty-four percent of the patients had single lesions and 21% recurrent lesions. Twelve patients had, or were known to develop, internal involvement, and in six patients the cause of death was KS. All but four cases histologically showed areas of solid proliferations of tumour cells consistent with plaque or tumour stage. An angiosarcoma-like histologic pattern appeared to be associated with more aggressive epidemiologic subsets. High mitotic rates were rarely seen and did not correlate with aggressive epidemiologic subsets.

CONCLUSION

Kaposi's sarcoma in women is diagnosed almost exclusively in plaque or tumour stage. The majority of women within our study fit within the epidemiologic subset of sporadic KS.

Kaposi's sarcoma in retrospect

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Generalized endemic Kaposi's sarcoma

Kaposi's sarcoma (KS) is a multicentric neoplasm thought to arise from both vascular and lymphatic endothelium. It is subdivided into four main categories on the basis of clinical features, course and prognosis. We report a 54-year-old Afro-Caribbean male, living in the UK for the past 26 years, with classic features of generalized endemic KS. Because he has never lived on the African continent, the role of genetic rather than environmental factors is favoured in the aetiology of KS in this individual. This disorder is rarely seen in Afro-Caribbeans living in the UK, who have never actually lived in Africa.

HIV-related tumors of the oral cavity

In HIV-infected patients with AIDS the most frequent malignancies are Kaposi's sarcoma and non-Hodgkin's lymphoma. In these patients, the natural history of these tumors is quite different from those of HIV-negative subjects. These tumors may present atypical clinical aspects, may be very aggressive, and the coexistence of immunosuppression and opportunistic infections may render their treatment more difficult. The aim of this article is to provide updated information on the epidemiology, pathogenesis, natural history, and management of tumors that develop in the oral cavity of patients with AIDS.

Kaposi's sarcoma: a review of gene expression and ultrastructure of KS spindle cells in vivo

The ultrastructural features and the gene expression pattern of Kaposi's sarcoma (KS) spindle cells in vivo suggest that KS is a tumor of the mixed cell type. The expression pattern of cytokines and cytokine receptors in the tumor lesion, together with the results obtained from in vitro characterization of KS-derived cells, provide evidence that paracrine mechanisms of growth factor action are important for the maintenance of KS. The reports on virus infection of KS cells suggest an indirect role of virus infection in the induction of KS, most likely mediated by immunostimulation and subsequent production of cytokines.

Kaposi's sarcoma and non-Hodgkin's lymphoma in European AIDS cases. No excess risk of Kaposi's sarcoma in Mediterranean countries

Prior to the AIDS epidemic, Kaposi's sarcoma (non-AIDS-KS) in Europe was mainly a disease of elderly Mediterranean men. In 1989 AIDS data from 15 European countries were collected to study proportional trends in AIDS-related Kaposi's sarcoma (AIDS-KS) in order to determine whether specific factors in Southern Europe might be important in the development of KS among AIDS patients. Another AIDS-related cancer, non-Hodgkin's lymphoma (NHL) was included as a malignancy control. Of 22,367 AIDS cases reported, 3,779 (16.9%) were KS and 741 (3.3%) were NHL. A significant, continuous fall in the percentage of AIDS-KS was seen for both homosexual men and other members of exposure groups during the period 1981-89 (p-trend less than 0.0001). The proportion with AIDS-KS decreased from 40.5% in 1983 to 26.5% in 1988 in homosexual men and from 12.2 to 3.6% in other exposure groups, respectively. No significant change was observed in the proportion of NHL cases among any of the risk groups over time, although a tendency towards a slight increase was noted for homosexual men. Comparing proportional trends of KS and NHL geographically, no significant difference was found overall, by time or by exposure group. In conclusion, a specific decline is observed over time for AIDS-KS. However, if geographically-restricted factors are important in the development of non-AIDS-KS in Europe, the same factors do not appear to affect the risk of AIDS-KS.

Major histocompatibility complex class I to III allotypes in patients with AIDS-related complex/Walter-Reed 5, disseminated Kaposi's sarcoma and in normal controls. The ARC-IVIG Study Group

In HIV-infected patients major histocompatibility complex (MHC) class I and II (= HLA-A, B, C, DR) association has been controversial. Of the MHC class III coded complement components C2, BF, C4A/C4B especially C4 allotypes appear of major immunogenetic relevance for their potential differences in virus neutralizing potency and immune complex formation. In the present study 29 patients with AIDS-related complex and Walter-Reed 5 ARC/WR5), 35 patients with disseminated Kaposi's sarcoma (KS), and 160 HIV-negative control individuals were compared for MHC class I to III allotypes. Diagnosis of ARC and KS (WR criteria) was done by clinical and laboratory parameters, MHC testing, by standard procedures. An increase in frequency (p less than or equal to 0.05) was observed between ARC/WR5 patients and controls for HLA-B35/CW4, DRW14, a decrease for B16, CW6/DR7. However, values were not significant if corrected for the number of tested antigens. No significant differences were seen between KS and ARC patients or controls for class III allotypes, nor for previously reported associations, e.g. for B8, DR2, DR3, and especially DR5, including the DR5 splits DRW11, 12. The results indicate the lack of a strong MHC association with the investigated antigens in West German Caucasoids, and support the hypothesis of ethnic dependence of HIV-related diseases. The HLA-B35/CW4 increase, also associated with the duplicated C4 A*3 A*2 and the silent C4B*Q0, was more pronounced in ARC patients with progression to AIDS-OI. The increased frequency of C4B*Q0 alleles in these patients was thought to be secondary to a hypothetical increase in 'converted' and dysregulated C4 genes not seen to be associated in this study.