Socio-economic and other correlates of Kaposi sarcoma-associated herpesvirus seroprevalence among older adults in Sicily

Epidemiology of Kaposi's Sarcoma

Kaposi's sarcoma is an angioproliferative tumor caused by human herpesvirus 8 in the context of immunodeficiency, such as that induced by HIV infection or immunosuppressive therapy. Its incidence has dramatically fallen in patients living with HIV (PLHIV) since the introduction of potent antiretroviral combinations 25 years ago due to the restoration of immunity and better control of HIV replication. However, KS is still one of the most frequently occurring cancers in PLHIV, in particular in men who have sex with men and in sub-Saharan Africa, where it is still endemic. Even in the context of restored immunity, the risk of KS is still more than 30 times higher in PLHIV than in the general population. Recent evidence indicates that early initiation of antiretroviral treatment, which is recommended by current guidelines, may reduce the risk of KS but it needs to be accompanied by early access to care. This review mainly focuses on the recent epidemiological features of KS in the context of HIV infection.

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.

Ultraviolet Radiation and Kaposi Sarcoma Incidence in a Nationwide US Cohort of HIV-Infected Men

Background

Although ultraviolet radiation (UVR) is established as both an inducer of herpes simplex virus reactivation and as the primary risk factor for many common skin cancers, its relationship with human herpes virus 8 (HHV8) infection or risk of Kaposi sarcoma (KS) is unknown.

Methods

Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for the association between ambient UVR, history of nonmelanoma skin cancer (NMSC; as a biomarker of personal cumulative UVR dose), and incidence of first primary KS in a nationwide US cohort of white and African American male veterans infected with HIV between 1986 and 1996 (prior to the widespread availability of treatment) using Cox regression. All statistical tests were two-sided.

Results

Based on discharge records, there were 422 newly diagnosed KS cases among 17 597 HIV-infected veterans. Cohort members with prior NMSC had a statistically significantly increased risk of KS (HR = 8.64, 95% CI = 6.23 to 11.96) in the total population. Risk of KS was higher for quartile 4 vs 1 among the total population (HR = 1.49, 95% CI = 1.02 to 2.16, P_trend UVR quartile [coded 1 to 4] = .02) and among whites (HR = 1.75, 95% CI = 1.11 to 2.78, P_trend = .009), but not among African Americans (HR = 1.23, 95% CI = 0.71 to 2.15, P_trend = .23).

Conclusions

KS risk was elevated among HIV-infected men with NMSC diagnosis and in those living in locations with high ambient UVR at time of HIV diagnosis. Our novel findings suggesting that UVR exposure may increase KS risk warrant further investigation.

Seroprevalence and risk factors of Kaposi's sarcoma-associated herpesvirus infection among the general Uygur population from south and north region of Xinjiang, China

Background

Kaposi sarcoma (KS) is a complex multifocal neoplasm and is the major cause of death for about 50% of acquired immunodeficiency syndrome (AIDS) patients. Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic virus with a causal role in the development of all types of KS. KS is prevalent among the Uygur people in Xinjiang, especially in south area. Here we carried out a cross-sectional study among 1534 general Uygur individuals from south and north region of Xinjiang to assess the seroprevalence of KSHV and to identify the potential correlation between KSHV seroprevalence and KS incidence.

Results

Seroprevalence of KSHV in South and North Xinjiang was 23.1% and 25.9%, respectively. Older age was independently associated with higher KSHV seroprevalence. In subjects from South Xinjiang, lower educational level and reported drinking were each independently associated with higher KSHV seroprevalence. Furthermore, the antibody titer was significantly lower in both south and north KSHV seropositive individuals compared with KS patients, as analyzed by gradient dilution (P < 0.001).

Conclusion

KSHV is highly prevalent in the general Uygur population in both South and North Xinjiang. Interestingly, the infection rate of KSHV in these two geographical areas did not correlate well with KS incidence. Perhaps unknown factors exist that promote the progression of KSHV infection to KS development in the local minority groups.

Delayed-type hypersensitivity in classic Kaposi sarcoma patients and controls

Background:

Immune perturbation likely affects the development of Kaposi sarcoma (KS) among people infected with the KS-associated herpesvirus (KSHV). We tested whether KSHV-seropositive individuals or cases of classic KS (cKS), which typically originates in the leg, had differing delayed-type hypersensitivity (DTH) in the forearm or leg.

Methods:

Mantoux DTH with three antigens (Candida, tetanus, PPD) was performed on the forearm and leg of 15 cKS cases, 14 KSHV-positives without KS, and 15 KSHV-negative controls. The diameters of induration responses were compared by group and body site.

Results:

Leg DTH was greater than forearm DTH among controls (mean difference 5.6 mm, P=0.0004), whereas this was not observed in cKS cases (−2.2 mm, P=0.32) or KSHV-positives (0.5 mm, P=0.56). Leg-minus-forearm DTH difference was greater in controls compared with cKS cases (P=0.004) and KSHV-positives (P=0.002). Leg-plus-forearm DTH was similar in controls (mean 28.2 mm) and cKS cases (24.5 mm, P=0.60), but it was reduced in KSHV-positives (11.8 mm, P=0.02), particularly in the leg (P=0.004) and marginally in the forearm (P=0.07).

Conclusion:

KS cases had weaker DTH only in the leg, whereas both body sites appeared weaker in KSHV-positives without KS. Both systemic and regional immune alterations may influence the development of this malignancy.

Risk of classic Kaposi sarcoma with exposures to plants and soils in Sicily

Background

Ecologic and in vitro studies suggest that exposures to plants or soil may influence risk of Kaposi sarcoma (KS).

Methods

In a population-based study of Sicily, we analyzed data on contact with 20 plants and residential exposure to 17 soils reported by 122 classic KS cases and 840 sex- and age-matched controls. With 88 KS-associated herpesvirus (KSHV) seropositive controls as the referent group, novel correlates of KS risk were sought, along with factors distinguishing seronegatives, in multinomial logistic regression models that included matching variables and known KS cofactors - smoking, cortisone use, and diabetes history. All plants were summed for cumulative exposure. Factor and cluster analyses were used to obtain scores and groups, respectively. Individual plants and soils in three levels of exposure with P_trend ≤ 0.15 were retained in a backward elimination regression model.

Results

Adjusted for known cofactors, KS was not related to cumulative exposures to 20 plants [per quartile adjusted odds ratio (OR_adj) 0.96, 95% confidence interval (CI) 0.73 - 1.25, P_trend = 0.87], nor was it related to any factor scores or cluster of plants (P = 0.11 to 0.81). In the elimination regression model, KS risk was associated with five plants (P_trend = 0.02 to 0.10) and with residential exposure to six soils (P_trend = 0.01 to 0.13), including three soils (eutric regosol, chromic/pellic vertisol) used to cultivate durum wheat. None of the KS-associated plants and only one soil was also associated with KSHV serostatus. Diabetes was associated with KSHV seronegativity (OR_adj 4.69, 95% CI 1.97 - 11.17), but the plant and soil associations had little effect on previous findings that KS risk was elevated for diabetics (OR_adj 7.47, 95% CI 3.04 - 18.35) and lower for current and former smokers (OR_adj 0.26 and 0.47, respectively, P_trend = 0.05).

Conclusions

KS risk was associated with exposure to a few plants and soils, but these may merely be due to chance. Study of the effects of durum wheat, which was previously associated with cKS, may be warranted.