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.

A multiplex panel of plasma markers of immunity and inflammation in classical kaposi sarcoma

Kaposi sarcoma (KS) risk is affected by perturbed immunity. Herein, we compared plasma from 15 human immunodeficiency virus (HIV)-negative classic KS cases to plasma from 29 matched controls, using a multiplex panel of immunity markers. Of 70 markers, CXCL10 (IP-10), sIL-1RII, sIL-2RA, and CCL3 (MIP-1A) were strongly and significantly associated with KS, after adjustment for age and smoking status. These and previous observations are consistent with a tumor-promoting role for these cytokines, particularly CXCL10, but the small sample size and case-control design preclude firm conclusions on KS risk or pathogenesis. Larger, well-designed prospective studies are needed to better assess the association of these markers with KS.

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.

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

The virus that causes Kaposi sarcoma, KS-associated herpesvirus (KSHV, also known as human herpesvirus 8) has an unusual distribution and poorly characterized modes of transmission. To clarify these issues, socio-demographic correlates of KSHV seroprevalence were examined in a population-based study. In 1,154 randomly sampled adults (aged 32- 92, mean 71 years) throughout Sicily, KSHV antibodies were detected with four assays and a conservative algorithm. Seroprevalence was re-weighted to the population. Odds ratios with 95% confidence intervals (OR, CI) from multivariate logistic regression were used to estimate associations of seroprevalence with interview data. KSHV seroprevalence was 8.5%, including 5.3% among men (N = 848) and 11.5% among women (N = 306, P = 0.22). Seroprevalence was higher with residence in a smaller community during childhood (P(trend) = 0.03) and working with plants/soil during adulthood (OR 2.9, CI 1.1-7.9); these were especially strong among women. Among men, seroprevalence was significantly associated with lower education (OR 2.6, CI 1.1-5.9) and migration to a larger community (OR 0.3, CI 0.1-0.9). Other demographic and household variables were unrelated to seroprevalence. From these data, KSHV in Sicily appears to be related to low socio-economic status, but micro-endemicity in small communities cannot be excluded.

Risk of classic Kaposi sarcoma with residential exposure to volcanic and related soils in Sicily

PURPOSE

Before AIDS, endemic (African) Kaposi sarcoma (KS) was noted to occur in volcanic areas and was postulated to result from dirt chronically embedded in the skin of the lower extremities. The primary cause of all KS types is KS-associated herpesvirus (KSHV) infection, but cofactors contribute to the neoplasia. We investigated whether residential exposure to volcanic or related soils was associated with the risk of classic Kaposi sarcoma (cKS) in Sicily.

METHODS

Risk of incident cKS (N=141) compared with population-based KSHV seropositive controls (N=123) was estimated for residential exposure to four types of soil, categorized with maps from the European Soil Database and direct surveying. Questionnaire data provided covariates.

RESULTS

Residents in communities high in luvisols were approximately 2.7 times more likely to have cKS than those in communities with no luvisols. Risk was not specific for cKS on the limbs, but it was elevated approximately four- to five-fold with frequent bathing or tap water drinking in communities with high luvisols. Risk was unrelated to communities high in andosols, tephra, or clay soils.

CONCLUSIONS

Iron and alumino-silicate clay, major components of luvisols, may increase cKS risk, but formal investigation and consideration of other soil types and exposures are needed.

Risk factors for classical Kaposi sarcoma in a population-based case-control study in Sicily

BACKGROUND

Classical Kaposi sarcoma is a rare complication of Kaposi sarcoma-associated herpes virus (KSHV) infection. We conducted a population-based, frequency-matched case-control study in Sicily to further investigate the reported inverse relationship between smoking and classical Kaposi sarcoma and to identify other factors associated with altered risk.

METHODS

All incident, histologically confirmed classical Kaposi sarcoma cases in Sicily were eligible. A two-stage cluster sample design was applied to select population controls. KSHV seropositivity was determined using four antibody assays (K8.1 and orf73 enzyme immunoassays and two immunofluorenscence assays). Using SAS-callable SUDAAN, we compared the characteristics of classical Kaposi sarcoma cases and KSHV-seropositive controls. Odds ratios (OR) and 95% confidence intervals (CI) are presented.

RESULTS

In total, 142 classical Kaposi sarcoma cases and 123 KSHV-seropositive controls were recruited. Current cigarette smoking was associated with reduced risk of classical Kaposi sarcoma amongst males (OR, 0.20; 95% CI, 0.06-0.67). Edema was associated with classical Kaposi sarcoma, but only when it presented on the lower extremities (OR, 3.65; 95% CI, 1.62-8.23). Irrespective of presentation site, diabetes and oral corticosteroid medications were associated with increased risk (OR, 4.73; 95% CI, 2.02-11.1 and OR, 2.34; 95% CI, 1.23-4.45, respectively). Never smoking, diabetes, and oral corticosteroid medication use were all independently associated with classical Kaposi sarcoma risk.

DISCUSSION

We confirmed previous reports that cigarette smoking was associated with a reduced risk of classical Kaposi sarcoma, and we found that risk was lowest among current smokers. We also found that classical Kaposi sarcoma risk was strongly and independently associated with oral corticosteroid use and diabetes. Corroboration of these observations and investigation of possible underlying mechanisms are warranted.

Is 2,3,5-pyrroletricarboxylic acid in hair a better risk indicator for melanoma than traditional epidemiologic measures for skin phenotype?

This study aims to assess type of melanin as a risk indicator for skin tumors, in a sample of melanoma cases and controls within a larger multicenter study (Helios 2), held in Europe and South America in 2001-2002. In each case and control, the melanin content in hair was assessed by three methods: 1) the amount of 2,3,5-pyrroletricarboxylic acid (PTCA); 2) the absorbance ratio with ultraviolet spectroscopy; and 3) the spectra of near-infrared spectroscopy. Statistical analysis was performed in a Bayesian setting, defining priors for confounders and effect modifiers from the larger study data set. Subjects with values of PTCA of less than 85 ng/mg carried an increased risk (26 vs. seven discordant pairs: odds ratio = 4.4, 95% confidence interval: 1.52, 14.54), adjusted by hair color, eye color, and number of nevi (n = > or =40). The absorbance ratio showed a weaker and nonsignificant odds ratio of 1.5. After correction by misclassification, near-infrared spectroscopy was associated with an odds ratio of 2.3 (95% confidence interval: 1.36, 4.22). The amount of PTCA is thus a strong and independent risk indicator for melanoma. Incorporating PTCA determination into epidemiologic studies is therefore recommended.

Virologic, hematologic, and immunologic risk factors for classic Kaposi sarcoma

BACKGROUND

Classic Kaposi sarcoma (CKS) is an inflammatory-mediated neoplasm that develops in the presence of KS-associated herpesvirus (KSHV) and immune perturbation. In the current study, the authors compared CKS cases with age-matched and sex-matched KSHV-seropositive controls without human immunodeficiency virus-1 infection and markers of viral control, blood counts, CD4-positive and CD8-positive lymphocytes, and serum beta-2-microglobulin and neopterin levels.

METHODS

Viral loads were detected using real-time amplification of the KSHV-K6 and EBV-pol genes, anti-K8.1 (lytic) titers were detected by enzyme-linked immunoadsorbent assay, and antilatent nuclear antigen (LANA) titers were detected using immunofluorescence. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using logistic regression adjusted for sex, age, and study site.

RESULTS

Peripheral blood mononuclear cells (PBMC) KSHV DNA detection (P < or = .0001) and high KSHV lytic (>1:1745; P < or = .0001) and latent (>1:102,400; P = .03) antibody titers were found to be positively associated with CKS risk. Antibody titers were higher in cases with lesions compared with cases without lesions (P < or =.05). The detection of Epstein-Barr virus (EBV) DNA in PBMCs was not found to be associated with CKS (P = .95). Independent of PBMC KSHV DNA, CKS risk was found to be positively associated with reduced hematocrit (<37.4%; P = .03), hemoglobin (<12g/dL; P = .04), and lymphocytes (<1000 cells/microL; P = .004), including CD4-positive (+) cells (<457 cells/microL; P = .07) and CD8+ cells (<213cells/microL; P = .04), and with increased monocytes (> or =638 cells/microL; P = .009). Nonsignificant elevations of beta-2-microglobulin and neopterin were observed among cases regardless of disease burden (P > or = .08). In a multivariate model, the CKS risk was found to be associated with PBMC KSHV DNA (OR of 2.7; 95% CI, 1.4-5.3), a high KSHV lytic antibody titer (OR of 3.7; 95% CI, 1.9-7.4), and low lymphocytes, particularly among those patients age <70 years (OR of 8.0; 95% CI, 2.7-23.7).

CONCLUSIONS

The findings of the current study appear to corroborate the specificity of KSHV and highlight the hematologic and immunologic correlates involved in the pathogenesis of CKS.

Associations of Classic Kaposi Sarcoma with Common Variants in Genes that Modulate Host Immunity

Classic Kaposi sarcoma (CKS) is an inflammatory-mediated neoplasm primarily caused by Kaposi sarcoma-associated herpesvirus (KSHV). Kaposi sarcoma lesions are characterized, in part, by the presence of proinflammatory cytokines and growth factors thought to regulate KSHV replication and CKS pathogenesis. Using genomic DNA extracted from 133 CKS cases and 172 KSHV-latent nuclear antigen-positive, population-based controls in Italy without HIV infection, we examined the risk of CKS associated with 28 common genetic variants in 14 immune-modulating genes. Haplotypes were estimated for IL1A, IL1B, IL4, IL8, IL8RB, IL10, IL12A, IL13, and TNF. Compared with controls, CKS risk was decreased with 1235T/-1010G-containing diplotypes of IL8RB (odds ratio, 0.49; 95% confidence interval, 0.30-0.78; P = 0.003), whereas risk was increased with diplotypes of IL13 containing the promoter region variant 98A (rs20541, alias +130; odds ratio, 1.88; 95% confidence interval, 1.15-3.08; P = 0.01) when considered in multivariate analysis. Risk estimates did not substantially vary by age, sex, incident disease, or disease burden. Our data provide preliminary evidence for variants in immune-modulating genes that could influence the risk of CKS. Among KSHV-seropositive Italians, CKS risk was associated with diplotypes of IL8RB and IL13, supporting laboratory evidence of immune-mediated pathogenesis.

Host immunogenetics and control of human herpesvirus-8 infection

BACKGROUND

Kaposi sarcoma (KS) is primarily caused by human herpesvirus (HHV)-8 infection, and the risk is increased with high HHV-8 lytic or latent antibody titers or the detection of HHV-8 DNA in peripheral blood mononuclear cells (PBMCs). Host genes important for control of HHV-8 infection are not well characterized.

METHODS

In 172 HHV-8 latent nuclear antigen (LANA)-seropositive adults in Italy without KS, we examined correlations of common variants in host immune genes with the detection of HHV-8 DNA in PBMCs and with high lytic and latent antibody titers. Twenty-eight single-nucleotide polymorphisms in 14 genes were analyzed. We detected HHV-8 DNA in PBMCs with real-time amplification of the K6 gene, anti-K8.1 (lytic) titers with enzyme-linked immunosorbent assay, and anti-LANA (latent) titers with immunofluorescence.

RESULTS

Detection of HHV-8 DNA in PBMCs was not significantly related to any variant examined. In contrast, a 3-locus haplotype of IL4, which contains the -1098G allele (rs2243248), was overrepresented among subjects with high lytic titers (odds ratio [OR], 2.8 [95% confidence interval {CI}, 1.1-6.7]), compared with those with low titers, as was the functional promoter variant of IL6, C-236C (rs1800795) (OR, 3.7 [95% CI, 1.1-12.8]). Compared with subjects with low HHV-8 latent antibody titers, analysis of inferred haplotypes for IL12A revealed an overrepresentation of -798T/277A in subjects with high HHV-8 latent antibody titers (OR, 2.4 [95% CI, 1.1-5.2]).

CONCLUSIONS

Our observations are the first to provide preliminary evidence suggesting that common variants in key host immune genes could influence the control of HHV-8 infection.

A common genetic variant in FCGR3A-V158F and risk of Kaposi sarcoma herpesvirus infection and classic Kaposi sarcoma

Associations of FCGR3A among men with HIV/acquired immunodeficiency syndrome suggest that host responses affect the pathogenesis of Kaposi sarcoma herpesvirus (KSHV) infection and risk of acquired immunodeficiency syndrome-associated Kaposi sarcoma. Using DNA from two HIV seronegative case-control populations in Italy, we examined whether the functional FCGR3A-V158F variant was associated with risk of KSHV infection or classic Kaposi sarcoma (CKS). In population I, we examined FCGR3A variants and risk of KSHV infection in 34 KSHV latent nuclear antigen (LANA)-seropositive and 120 LANA-seronegative adults from Sardinia (52% male; median age, 45 years; range, 31-60), whereas in population II, we examined risk of CKS from 133 CKS cases and 172 KSHV LANA-seropositive controls from Sicily, Rome, and Naples (70% males; median age, 74 years; range, 29-91). FCGR3A variants were determined by direct sequence analysis of a nested PCR of genomic DNA assay using allele-specific primers. KSHV LANA was determined by immunofluorescence assay. Overall, compared with the 158F allele, 158V was overrepresented among controls from both Mediterranean populations (frequency = 0.52 and 0.51, respectively). After controlling for age, 158V homozygous women were at increased risk of KSHV infection and CKS compared with 158F homozygous women [odds ratio (OR), 8.7; 95% confidence interval (95% CI), 0.8-98 and OR, 3.8; 95% CI, 1.0-14, respectively], whereas homozygous men were at decreased risk (OR, 0.4; 95% CI, 0.1-2.3 and OR, 0.4; 95% CI, 0.2-0.8, respectively). Significant gene-dose effects were observed among men and women at risk for CKS (P(trend) < or = 0.05). Our findings suggest that gender differences could possibly modify the effect of FCGR3A on risk of KSHV infection and CKS. Additional studies are required to confirm these relationships and determine their etiologic significance.

Risk factors for classical Kaposi's sarcoma

BACKGROUND

Classical Kaposi's sarcoma (KS) is a malignancy of lymphatic endothelial skin cells. Although all forms of KS are associated with the KS-associated herpesvirus (KSHV), classical KS occurs in a small fraction of KSHV-infected people. We sought to identify risk factors for classical KS in KSHV-infected individuals.

METHODS

Lifestyle and medical history data from case patients with biopsy-proven non-AIDS (non-acquired immunodeficiency syndrome) KS in Italy were compared by logistic regression analysis with data from population-based KSHV-seropositive control subjects of comparable age and sex. After KSHV immunofluorescence testing, randomly selected patients on the rosters of local physicians were identified as control subjects. Risk of KS was estimated by odds ratios (ORs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

From April 13, 1998, through October 8, 2001, we enrolled 141 classical KS case patients and 192 KSHV-seropositive control subjects of similar age (mean = 72 years for case patients and 73 years for control subjects) and sex (30% female case patients and 35% female control subjects). The strongest association was a reduced risk of KS with cigarette smoking (OR = 0.25, 95% CI = 0.14 to 0.45). Cigarette smoking intensity and duration could be evaluated for men, among whom the risk for KS was inversely related to the amount of cumulative smoking (P(trend)<.001). KS risk decreased approximately 20% (OR = 0.81, 95% CI = 0.74 to 0.89) for each 10 pack-years reported, and it was decreased sevenfold (OR = 0.14, 95% CI = 0.07 to 0.30) with more than 40 pack-years. In multivariable analysis, a decreased KS risk was associated with smoking (OR = 0.23, 95% CI = 0.12 to 0.44); but an increased KS risk was associated with topical corticosteroid use (OR = 2.73, 95% CI = 1.35 to 5.51), infrequent bathing (OR = 1.85, 95% CI = 1.04 to 3.33), and a history of asthma (OR = 2.18, 95% CI = 0.95 to 4.97) or of allergy among men (OR = 2.59, 95% CI = 1.15 to 5.83) but not among women (OR = 0.09, 95% CI = 0.003 to 2.76). KS was not related to other exposures or illnesses examined.

CONCLUSION

Risk for classical KS was approximately fourfold lower in cigarette smokers, a result that requires confirmation by other studies. Identification of how smoking affects KS risk may lead to a better understanding of the pathogenesis of this malignancy and interventions for its prevention.

European Prospective Investigation into Cancer and Nutrition (EPIC) calibration study: rationale, design and population characteristics

The European Prospective Investigation into Cancer and Nutrition (EPIC), which covers a large cohort of half a million men and women from 23 European centres in 10 Western European countries, was designed to study the relationship between diet and the risk of chronic diseases, particularly cancer. Information on usual individual dietary intake was assessed using different validated dietary assessment methods across participating countries. In order to adjust for possible systematic over- or underestimation in dietary intake measurements and correct for attenuation bias in relative risk estimates, a calibration approach was developed. This approach involved an additional dietary assessment common across study populations to re-express individual dietary intakes according to the same reference scale. A single 24-hour diet recall was therefore collected, as the EPIC reference calibration method, from a stratified random sample of 36 900 subjects from the entire EPIC cohort, using a software program (EPIC-SOFT) specifically designed to standardise the dietary measurements across study populations. This paper describes the design and populations of the calibration sub-studies set up in the EPIC centres. In addition, to assess whether the calibration sub-samples were representative of the entire group of EPIC cohorts, a series of subjects' characteristics known possibly to influence dietary intakes was compared in both population groups. This was the first time that calibration sub-studies had been set up in a large multi-centre European study. These studies showed that, despite certain inherent methodological and logistic constraints, a study design such as this one works relatively well in practice. The average response in the calibration study was 78.3% and ranged from 46.5% to 92.5%. The calibration population differed slightly from the overall cohort but the differences were small for most characteristics and centres. The overall results suggest that, after adjustment for age, dietary intakes estimated from calibration samples can reasonably be interpreted as representative of the main cohorts in most of the EPIC centres.

Evaluation of under- and overreporting of energy intake in the 24-hour diet recalls in the European Prospective Investigation into Cancer and Nutrition (EPIC)

OBJECTIVE

To evaluate under- and overreporting and their determinants in the EPIC 24-hour diet recall (24-HDR) measurements collected in the European Prospective Investigation into Cancer and Nutrition (EPIC).

DESIGN

Cross-sectional analysis. 24-HDR measurements were obtained by means of a standardised computerised interview program (EPIC-SOFT). The ratio of reported energy intake (EI) to estimated basal metabolic rate (BMR) was used to ascertain the magnitude, impact and determinants of misreporting. Goldberg's cut-off points were used to identify participants with physiologically extreme low or high energy intake. At the aggregate level the value of 1.55 for physical activity level (PAL) was chosen as reference. At the individual level we used multivariate statistical techniques to identify factors that could explain EI/BMR variability. Analyses were performed by adjusting for weight, height, age at recall, special diet, smoking status, day of recall (weekday vs. weekend day) and physical activity.

SETTING

Twenty-seven redefined centres in the 10 countries participating in the EPIC project.

SUBJECTS

In total, 35 955 men and women, aged 35-74 years, participating in the nested EPIC calibration sub-studies.

RESULTS

While overreporting has only a minor impact, the percentage of subjects identified as extreme underreporters was 13.8% and 10.3% in women and men, respectively. Mean EI/BMR values in men and women were 1.44 and 1.36 including all subjects, and 1.50 and 1.44 after exclusion of misreporters. After exclusion of misreporters, adjusted EI/BMR means were consistently less than 10% different from the expected value of 1.55 for PAL (except for women in Greece and in the UK), with overall differences equal to 4.0% and 7.4% for men and women, respectively. We modelled the probability of being an underreporter in association with several individual characteristics. After adjustment for age, height, special diet, smoking status, day of recall and physical activity at work, logistic regression analyses resulted in an odds ratio (OR) of being an underreporter for the highest vs. the lowest quartile of body mass index (BMI) of 3.52 (95% confidence interval (CI) 2.91-4.26) in men and 4.80 (95% CI 4.11-5.61) in women, indicating that overweight subjects are significantly more likely to underestimate energy intake than subjects in the bottom BMI category. Older people were less likely to underestimate energy intake: ORs were 0.58 (95% CI 0.45-0.77) and 0.74 (95% CI 0.63-0.88) for age (> or =65 years vs. <50 years). Special diet and day of the week showed strong effects.

CONCLUSION

EI tends to be underestimated in the vast majority of the EPIC centres, although to varying degrees; at the aggregate level most centres were below the expected reference value of 1.55. Underreporting seems to be more prevalent among women than men in the EPIC calibration sample. The hypothesis that BMI (or weight) and age are causally related to underreporting seems to be confirmed in the present work. This introduces further complexity in the within-group (centre or country) and between-group calibration of dietary questionnaire measurements to deattenuate the diet-disease relationship.

Risk factors for classical Kaposi's sarcoma

BACKGROUND

Classical Kaposi's sarcoma (KS) is a malignancy of lymphatic endothelial skin cells. Although all forms of KS are associated with the KS-associated herpesvirus (KSHV), classical KS occurs in a small fraction of KSHV-infected people. We sought to identify risk factors for classical KS in KSHV-infected individuals.

METHODS

Lifestyle and medical history data from case patients with biopsy-proven non-AIDS (non-acquired immunodeficiency syndrome) KS in Italy were compared by logistic regression analysis with data from population-based KSHV-seropositive control subjects of comparable age and sex. After KSHV immunofluorescence testing, randomly selected patients on the rosters of local physicians were identified as control subjects. Risk of KS was estimated by odds ratios (ORs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

From April 13, 1998, through October 8, 2001, we enrolled 141 classical KS case patients and 192 KSHV-seropositive control subjects of similar age (mean = 72 years for case patients and 73 years for control subjects) and sex (30% female case patients and 35% female control subjects). The strongest association was a reduced risk of KS with cigarette smoking (OR = 0.25, 95% CI = 0.14 to 0.45). Cigarette smoking intensity and duration could be evaluated for men, among whom the risk for KS was inversely related to the amount of cumulative smoking (P(trend)<.001). KS risk decreased approximately 20% (OR = 0.81, 95% CI = 0.74 to 0.89) for each 10 pack-years reported, and it was decreased sevenfold (OR = 0.14, 95% CI = 0.07 to 0.30) with more than 40 pack-years. In multivariable analysis, a decreased KS risk was associated with smoking (OR = 0.23, 95% CI = 0.12 to 0.44); but an increased KS risk was associated with topical corticosteroid use (OR = 2.73, 95% CI = 1.35 to 5.51), infrequent bathing (OR = 1.85, 95% CI = 1.04 to 3.33), and a history of asthma (OR = 2.18, 95% CI = 0.95 to 4.97) or of allergy among men (OR = 2.59, 95% CI = 1.15 to 5.83) but not among women (OR = 0.09, 95% CI = 0.003 to 2.76). KS was not related to other exposures or illnesses examined.

CONCLUSION

Risk for classical KS was approximately fourfold lower in cigarette smokers, a result that requires confirmation by other studies. Identification of how smoking affects KS risk may lead to a better understanding of the pathogenesis of this malignancy and interventions for its prevention.

Effect of alpha-interferon on natural killer cell activity and lymphocyte subsets in thalassemia patients with chronic hepatitis C

The variation of natural killer (NK) cell activity and lymphocyte subsets 20 h after a single test dose of alpha-IFN, was studied in 17 thalassemic patients with chronic hepatitis C. All patients had suspended the alpha-IFN therapy at least 12 months before the study: 10 were considered responders and 7 nonresponders. Also NK cell cytotoxicity after in vitro incubation with alpha-IFN was studied. The administration of a single dose of alpha-IFN increased NK cell cytotoxic activity significantly in the group of responders and in non-responders; moreover the NK cell cytotoxic activity after alpha-IFN in vitro incubation increased both in responders and nonresponders, but to a lesser degree than in healthy controls. Absolute values of CD4+ and CD8+ lymphocytes decreased significantly only in responders. In conclusion, our data suggest that the variation of NK cytotoxic activity and lymphocyte subsets after a test dose of alpha-IFN can be considered a parameter related to IFN biological effects.