Feasibility, long-term safety, and immune monitoring of regulatory T cell therapy in living donor kidney transplant recipients.

Short-term outcomes in kidney transplantation are marred by progressive transplant failure and mortality secondary to immunosuppression toxicity. Immune modulation with autologous polyclonal regulatory T cell (Treg) therapy may facilitate immunosuppression reduction promoting better long-term clinical outcomes. In a Phase I clinical trial, 12 kidney transplant recipients received 1-10 × 106 Treg per kg at Day +5 posttransplantation in lieu of induction immunosuppression (Treg Therapy cohort). Nineteen patients received standard immunosuppression (Reference cohort). Primary outcomes were rejection-free and patient survival. Patient and transplant survival was 100%; acute rejection-free survival was 100% in the Treg Therapy versus 78.9% in the reference cohort at 48 months posttransplant. Treg therapy revealed no excess safety concerns. Four patients in the Treg Therapy cohort had mycophenolate mofetil withdrawn successfully and remain on tacrolimus monotherapy. Treg infusion resulted in a long-lasting dose-dependent increase in peripheral blood Tregs together with an increase in marginal zone B cell numbers. We identified a pretransplantation immune phenotype suggesting a high risk of unsuccessful ex-vivo Treg expansion. Autologous Treg therapy is feasible, safe, and is potentially associated with a lower rejection rate than standard immunosuppression. Treg therapy may provide an exciting opportunity to minimize immunosuppression therapy and improve long-term outcomes.

Regulatory cell therapy in kidney transplantation (The ONE Study): a harmonised design and analysis of seven non-randomised, single-arm, phase 1/2A trials.

BACKGROUND: Use of cell-based medicinal products (CBMPs) represents a state-of-the-art approach for reducing general immunosuppression in organ transplantation. We tested multiple regulatory CBMPs in kidney transplant trials to establish the safety of regulatory CBMPs when combined with reduced immunosuppressive treatment. METHODS: The ONE Study consisted of seven investigator-led, single-arm trials done internationally at eight hospitals in France, Germany, Italy, the UK, and the USA (60 week follow-up). Included patients were living-donor kidney transplant recipients aged 18 years and older. The reference group trial (RGT) was a standard-of-care group given basiliximab, tapered steroids, mycophenolate mofetil, and tacrolimus. Six non-randomised phase 1/2A cell therapy group (CTG) trials were pooled and analysed, in which patients received one of six CBMPs containing regulatory T cells, dendritic cells, or macrophages; patient selection and immunosuppression mirrored the RGT, except basiliximab induction was substituted with CBMPs and mycophenolate mofetil tapering was allowed. None of the trials were randomised and none of the individuals involved were masked. The primary endpoint was biopsy-confirmed acute rejection (BCAR) within 60 weeks after transplantation; adverse event coding was centralised. The RTG and CTG trials are registered with ClinicalTrials.gov, NCT01656135, NCT02252055, NCT02085629, NCT02244801, NCT02371434, NCT02129881, and NCT02091232. FINDINGS: The seven trials took place between Dec 11, 2012, and Nov 14, 2018. Of 782 patients assessed for eligibility, 130 (17%) patients were enrolled and 104 were treated and included in the analysis. The 66 patients who were treated in the RGT were 73% male and had a median age of 47 years. The 38 patients who were treated across six CTG trials were 71% male and had a median age of 45 years. Standard-of-care immunosuppression in the recipients in the RGT resulted in a 12% BCAR rate (expected range 3·2-18·0). The overall BCAR rate for the six parallel CTG trials was 16%. 15 (40%) patients given CBMPs were successfully weaned from mycophenolate mofetil and maintained on tacrolimus monotherapy. Combined adverse event data and BCAR episodes from all six CTG trials revealed no safety concerns when compared with the RGT. Fewer episodes of infections were registered in CTG trials versus the RGT. INTERPRETATION: Regulatory cell therapy is achievable and safe in living-donor kidney transplant recipients, and is associated with fewer infectious complications, but similar rejection rates in the first year. Therefore, immune cell therapy is a potentially useful therapeutic approach in recipients of kidney transplant to minimise the burden of general immunosuppression. FUNDING: The 7th EU Framework Programme.

Pre-dialysis fluid status, pre-dialysis systolic blood pressure and outcome in prevalent haemodialysis patients: results of an international cohort study on behalf of the MONDO initiative.

Background: Pre-dialysis fluid overload (FO) associates with mortality and causes elevated pre-dialysis systolic blood pressure (pre-SBP). However, low pre-SBP is associated with increased mortality in haemodialysis patients. The objective of this study was to investigate the interaction between pre-dialysis fluid status (FS) and pre-SBP in association with mortality. Methods: We included all patients from the international Monitoring Dialysis Outcome Initiative (MONDO) database with a pre-dialysis multifrequency bioimpedance spectroscopy measurement in the year 2011. We used all parameters available during a 90-day baseline period. All-cause mortality was recorded during 1-year follow-up. Associations with outcome were assessed with Cox models and a smoothing spline Cox analysis. Results: We included 8883 patients. In patients with pre-dialysis FO (>+1.1 to +2.5 L), pre-SBP <110 mmHg was associated with an increased risk of death {hazard ratio (HR) 1.52 [95% confidence interval (CI) 1.06-2.17]}. An increased risk of death was also associated with pre-dialysis fluid depletion (FD; <-1.1 L) combined with a pre-SBP <140 mmHg. In normovolemic (NV) patients, low pre-SBP <110 mmHg was associated with better survival [HR 0.46 (95% CI 0.23-0.91)]. Also, post-dialysis FD associated with a survival benefit. Results were similar when inflammation was present. Only high ultrafiltration rate could not explain the higher mortality rates observed. Conclusion: The relation between pre-SBP and outcome is dependent on pre-dialysis FS. Low pre-SBP appears to be disadvantageous in patients with FO or FD, but not in NV patients. Post-dialysis FD was found to associate with improved survival. Therefore, we suggest interpreting pre-SBP levels in the context of FS and not as an isolated marker.

Familial hypercholesterolaemia: cholesterol efflux and coronary disease.

BACKGROUND: Coronary heart disease (CHD) risk inversely associates with levels of high-density lipoprotein cholesterol (HDL-C). The protective effect of HDL is thought to depend on its functionality, such as its ability to induce cholesterol efflux. MATERIALS AND METHODS: We compared plasma cholesterol efflux capacity between male familial hypercholesterolaemia (FH) patients with and without CHD relative to their non-FH brothers, and examined HDL constituents including sphingosine-1-phosphate (S1P) and its carrier apolipoprotein M (apoM). RESULTS: Seven FH patients were asymptomatic and six had experienced a cardiac event at a mean age of 39 years. Compared to their non-FH brothers, cholesterol efflux from macrophages to plasma from the FH patients without CHD was 16 ± 22% (mean ± SD) higher and to plasma from the FH patients with CHD was 7 ± 8% lower (P = 0·03, CHD vs. non-CHD). Compared to their non-FH brothers, FH patients without CHD displayed significantly higher levels of HDL-cholesterol, HDL-S1P and apoM, while FH patients with CHD displayed lower levels than their non-FH brothers. CONCLUSIONS: A higher plasma cholesterol efflux capacity and higher S1P and apoM content of HDL in asymptomatic FH patients may play a role in their apparent protection from premature CHD.

Regulatory T cells: first steps of clinical application in solid organ transplantation.

Solid organ transplantation is the treatment of choice for patients with end-stage organ failure. To prevent rejection of the transplanted organ continuous treatment with immunosuppressive medication is needed. Immunosuppression may be harmful to the transplant recipient, increasing the risk of cancer, infections and cardiovascular disease. To improve transplant and patient survival, there is a need for an immune-modulatory regimen that is not only potent in preventing rejection of the transplanted organ, but has less side effects compared to current immunosuppressive regimens. Increasingly, transplantation research focusses on regulatory T cell (Treg) therapy to achieve this aim, in which Treg are used as a strategy to allow reduction of immunosuppression. Currently, the first clinical trials are underway investigating the safety and feasibility of Treg therapy in renal transplantation. This review gives an overview of the rationale of using Treg therapy in transplantation, previous experience with Treg therapy in humans, and the expected safety, potential efficacy and cost-effectiveness of Treg therapy in solid organ transplantation.

Introducing the importance and difficulties of a three-step approach to improve nonadherence to antihypertensive drugs: a case series.

Nonadherence to antihypertensive drugs is an important reason for not reaching blood pressure goals. A possible method to improve nonadherence involves three essential steps: identification of nonadherent patients (step 1), determination of underlying causes (step 2) and a personalized solution (step 3). We present three unique cases to show the importance and difficulties of this three-step approach. Patients participated in a randomized controlled trial to improve nonadherence to antihypertensive drugs (RHYME-RCT, Dutch Trial Register NL6736). Drug level measurements were used to identify nonadherence to antihypertensive drugs and communication on drug levels was supported by a tailored feedback tool in these patients. These cases showed that a three-step approach of identifying nonadherence and determination of the underlying cause, can lead to a personalized solution to improve therapy even when nonadherence was excluded. Open communication with patients remains an essential part when improving nonadherence.

Value of genetic profiling for the prediction of coronary heart disease.

BACKGROUND: Advances in high-throughput genomics facilitate the identification of novel genetic susceptibility variants for coronary heart disease (CHD). This may improve CHD risk prediction. The aim of the present simulation study was to investigate to what degree CHD risk can be predicted by testing multiple genetic variants (genetic profiling). METHODS: We simulated genetic profiles for a population of 100,000 individuals with a 10-year CHD incidence of 10%. For each combination of model parameters (number of variants, genotype frequency and odds ratio [OR]), we calculated the area under the receiver operating characteristic curve (AUC) to indicate the discrimination between individuals who will and will not develop CHD. RESULTS: The AUC of genetic profiles could rise to 0.90 when 100 hypothetical variants with ORs of 1.5 and genotype frequencies of 50% were simulated. The AUC of a genetic profile consisting of 10 established variants, with ORs ranging from 1.13 to 1.42, was 0.59. When 2, 5, and 10 times as many identical variants would be identified, the AUCs were 0.63, 0.69, and 0.76. CONCLUSION: To obtain AUCs similar to those of conventional CHD risk predictors, a considerable number of additional common genetic variants need to be identified with preferably strong effects.

Gene-load score of the renin-angiotensin-aldosterone system is associated with coronary heart disease in familial hypercholesterolaemia.

AIMS: Familial hypercholesterolaemia (FH) is characterized by premature coronary heart disease (CHD). However, the incidence of CHD varies considerably among FH patients. Genetic variation in the renin-angiotensin-aldosterone system (RAAS) and the adrenalin/noradrenalin system may be of importance in determining the CHD risk in FH, because of their involvement in CHD. We investigated the association between CHD risk and combined genetic variation in the RAAS and adrenalin/noradrenalin system. METHODS AND RESULTS: In 2190 FH patients, we genotyped six RAAS polymorphisms and five adrenalin/noradrenalin polymorphisms. For each patient, we calculated two gene-load scores by counting the number of risk genotypes within each pathway. Four of the six RAAS polymorphisms and none of the polymorphisms in the adrenalin/noradrenalin system were significantly associated with CHD (P < 0.05). The RAAS gene-load score was significantly associated with CHD (P(linear trend) < 0.001): in patients with a gene-load score of 5 or 6, the CHD risk was 2.3 times as high as in patients with a score of 0 or 1. The gene-load score of the adrenalin/noradrenalin system was not associated with CHD. CONCLUSION: Genetic variation in the RAAS contributes gene-dose dependently to CHD risk in patients with FH, whereas genetic variation in the adrenalin/noradrenalin system is not associated with CHD.

Replication study of 10 genetic polymorphisms associated with coronary heart disease in a specific high-risk population with familial hypercholesterolemia.

AIMS: Recent large association studies have revealed associations between genetic polymorphisms and myocardial infarction and coronary heart disease (CHD). We performed a replication study of 10 polymorphisms and CHD in a population with familial hypercholesterolemia (FH), individuals at extreme risk of CHD. METHODS AND RESULTS: We genotyped 10 polymorphisms in 2145 FH patients and studied the association between these polymorphisms and CHD in Cox proportional hazards models. We confirmed the associations between four polymorphisms and CHD, the rs1151640 polymorphism in the olfactory receptor family 13 subfamily G member 1 (OR13G1) gene (HR 1.14, 95% CI 1.01-1.28, P = 0.03), the rs11881940 polymorphism in the heterogeneous nuclear ribonucleoprotein U-like 1 (HNRPUL1) gene (HR 1.27, 95% CI 1.07-1.51, P = 0.007), the rs3746731 polymorphism in the complement component 1 q subcomponent receptor 1 (CD93) gene (HR 1.26, 95% CI 1.06-1.49, P = 0.01), and the rs10757274 polymorphism near the cyclin-dependent kinase N2A and N2B (CDKN2A and CDKN2B) genes (HR 1.39, 95% CI 1.15-1.69, P < 0.001). CONCLUSION: We confirmed previously found associations between four polymorphisms and CHD, but refuted associations for six other polymorphisms in our large FH population. These findings stress the importance of replication before genetic information can be implemented in the prediction of CHD.

Citric-acid dialysate improves the calcification propensity of hemodialysis patients: A multicenter prospective randomized cross-over trial.

INTRODUCTION: The concentration of dialysate calcium (dCa) has been suggested to affect vascular calcification, but evidence is scarce. Calcification propensity reflects the intrinsic capacity of serum to prevent calcium and phosphate to precipitate. The use of citric-acid dialysate may have a beneficial effect on the calcification propensity due to the chelating effect on calcium and magnesium. The aim of this study was to compare the intradialytic and short-term effects of haemodialysis with either standard acetic-acid dialysate with dCa1.50 (A1.5) or dCa1.25 (A1.25), as well as citric-acid dialysate with dCa1.50 (C1.5) in bicarbonate dialysis on the calcification propensity of serum. METHODS: Chronic stable hemodialysis patients were included. This multicenter randomized cross-over study consisted out of a baseline week (A1.5), followed by the randomized sequence of A1.25 or C1.5 for one week after which the alternate treatment was provided after a washout week with A1.5. Calcification propensity of serum was assessed by time-resolved nephelometry where the T50 reflects the transition time between formation of primary and secondary calciprotein particles. RESULTS: Eighteen patients (median age 70 years) completed the study. Intradialytic change in T50 was increased with C1.5 (121 [90-152]min) compared to A1.25 (83 [43-108]min, p<0.001) and A1.5 (66 [18-102]min, p<0.001). During the treatment week, predialysis T50 increased significantly from the first to the third session with C1.5 (271 [234-291] to 280 [262-339]min, p = 0.002) and with A1.25 (274 [213-308] to 307 [256-337]min, p<0.001), but not with A1.5 (284 [235-346] to 300 [247-335]min, p = 0.33). CONCLUSION: Calcification propensity, as measured by the change in T50, improved significantly during treatment in C1.5 compared to A1.25 and A1.5. Long-term studies are needed to investigate the effects of different dialysate compositions concentrations on vascular calcification and bone mineral disorders.

Two common haplotypes of the glucocorticoid receptor gene are associated with increased susceptibility to cardiovascular disease in men with familial hypercholesterolemia.

CONTEXT: Glucocorticoids contribute to the development of atherosclerosis. Four polymorphisms in the glucocorticoid receptor (GR) gene have been reported to alter glucocorticoid sensitivity and have been associated with cardiovascular risk factors. Studies on the relationship between these GR variants and cardiovascular disease (CVD) risk, however, have yielded conflicting results. OBJECTIVE: We sought to determine whether haplotypes based on functional polymorphisms in the GR gene influenced susceptibility to CVD in a high-risk population. DESIGN, SETTING, AND PARTICIPANTS: In a multicenter cohort study, 1830 patients with heterozygous familial hypercholesterolemia were genotyped for the functional ER22/23EK, N363S, BclI, and 9beta variants. We analyzed the combined effect of all GR variants by constructing haplotypes and using a Cox proportional hazards regression model with adjustment for year of birth and smoking. The analyses were stratified for sex. MAIN OUTCOME MEASURES: The primary outcome measure was CVD defined as coronary, cerebral, and peripheral artery disease. RESULTS: A total of 359 men (40.8%) and 224 women (23.6%) had a cardiovascular event. In men, the BclI haplotype was associated with a 34% higher CVD risk (confidence interval 1.02-1.76; P = 0.03) and the 9beta haplotype with a 41% higher CVD risk (confidence interval 1.02-1.94; P = 0.04). In women, none of the GR haplotypes was significantly related with CVD. We did not find differences in cardiovascular risk factors between GR haplotypes. CONCLUSIONS: In this large cohort of high-risk individuals, two common haplotypes in the GR gene modified CVD susceptibility among men.

Cox proportional hazards models have more statistical power than logistic regression models in cross-sectional genetic association studies.

Cross-sectional genetic association studies can be analyzed using Cox proportional hazards models with age as time scale, if age at onset of disease is known for the cases and age at data collection is known for the controls. We assessed to what degree and under what conditions Cox proportional hazards models have more statistical power than logistic regression models in cross-sectional genetic association analyses. Analyses were conducted in an empirical study on the association of 65 polymorphisms and risk of coronary heart disease among 2400 familial hypercholesterolemia patients, and in a simulation study that considered various combinations of sample size, genotype frequency, and strength of association between the genotype and coronary heart disease. We applied Cox proportional hazards models and logistic regression models, and compared effect estimates (hazard ratios and odds ratios) and statistical power. In the empirical study, Cox proportional hazards models generally showed lower P-values for polymorphisms than logistic regression models. In the simulation study, Cox proportional hazards models had higher statistical power in all scenarios. Absolute differences in power did depend on the effect estimate, genotype frequency and sample size, and were most prominent for genotypes with minor effects. For example, when the genotype frequency was 30% in a sample with size n=2000 individuals, the absolute differences were the largest for effect estimates between 1.1 and 1.5. In conclusion, Cox proportional hazards models can increase statistical power in cross-sectional genetic association studies, especially in the range of effect estimates that are expected for genetic associations in common diseases.

Haplotype of the angiotensinogen gene is associated with coronary heart disease in familial hypercholesterolemia.

OBJECTIVE: Familial hypercholesterolemia is characterized by high plasma low-density lipoprotein cholesterol levels and premature coronary heart disease. Despite the monogenetic origin of familial hypercholesterolemia, the incidence of coronary heart disease varies considerably among patients, which is only partly explained by classical risk factors. Hypertension is an important risk factor for coronary heart disease that is associated with angiotensinogen levels. Therefore, we analyzed the angiotensinogen gene as a modifier gene for coronary heart disease risk in patients with familial hypercholesterolemia. METHODS: In a cohort of 1785 familial hypercholesterolemia patients, we reconstructed five frequent haplotypes of the angiotensinogen gene, based on four polymorphisms. The five haplotypes cover approximately 98% of the genetic diversity accounted for by these four polymorphisms. The associations between the haplotypes and coronary heart disease were analyzed with the haplo.stats program, adjusted for age, sex and smoking. RESULTS: Patients homozygous for the C allele of the 4072 T>C polymorphism had a 34% increased coronary heart disease risk (P = 0.017) compared to patients homozygous for the T allele. Haplotype H3, consisting of the minor allele of the 4072T>C polymorphism and the major alleles of the other polymorphisms, had a frequency of 15% and was associated with a 45% increased coronary heart disease risk (P = 0.006) compared to the wild-type haplotype H1. CONCLUSIONS: We conclude that genetic variation in the angiotensinogen gene contributes to coronary heart disease risk in patients with familial hypercholesterolemia.

Genome-based prediction of breast cancer risk in the general population: a modeling study based on meta-analyses of genetic associations.

BACKGROUND: Genome-wide association studies identified novel breast cancer susceptibility variants that could be used to predict breast cancer in asymptomatic women. This review and modeling study aimed to investigate the current and potential predictive performance of genetic risk models. METHODS: Genotypes and disease status were simulated for a population of 10,000 women. Genetic risk models were constructed from polymorphisms from meta-analysis including, in separate scenarios, all polymorphisms or statistically significant polymorphisms only. We additionally investigated the magnitude of the odds ratios (OR) for 1 to 100 hypothetical polymorphisms that would be needed to achieve similar discriminative accuracy as available prediction models [modeled range of area under the receiver operating characteristic curve (AUC) 0.70-0.80]. RESULTS: Of the 96 polymorphisms that had been investigated in meta-analyses, 41 showed significant associations. AUC was 0.68 for the genetic risk model based on all 96 polymorphisms and 0.67 for the 41 significant polymorphisms. Addition of 50 additional variants, each with risk allele frequencies of 0.30, requires per-allele ORs of 1.2 to increase this AUC to 0.70, 1.3 to increase AUC to 0.75, and 1.5 to increase AUC to 0.80. To achieve AUC of 0.80, even 100 additional variants would need per-allele ORs of 1.3 to 1.7, depending on risk allele frequencies. CONCLUSION: The predictive ability of genetic risk models in breast cancer has the potential to become comparable to that of current breast cancer risk models. IMPACT: Risk prediction based on low susceptibility variants becomes a realistic tool in prevention of nonfamilial breast cancer.

5-Lipoxygenase activating protein (ALOX5AP) gene variants associate with the presence of xanthomas in familial hypercholesterolemia.

BACKGROUND: Tendon xanthomas are characteristic for familial hypercholesterolemia (FH), and are associated with a higher risk of coronary heart disease (CHD). They often present with local inflammation. Inflammation may therefore be involved in their pathogenesis, as it is in the pathogenesis of CHD. A key role in the inflammatory pathway is played by the 5-lipoxygenase activating protein (ALOX5AP), which is known to influence the risk of CHD in FH. To test our hypothesis that ALOX5AP contributes to the development of xanthomas, we studied whether variants in the ALOX5AP gene influence the risk of xanthomas. METHODS: We examined 945 patients with genetically confirmed heterozygous FH to determine whether they had tendon xanthomas. We genotyped seven polymorphisms in the ALOX5AP gene and constructed haplotypes of these polymorphisms. RESULTS: The A allele of the rs9551963 polymorphism was associated with an increased risk of xanthomas (OR 1.52, 95% CI 1.11-2.07, p=0.01), while the A allele of rs17222842 was protective (OR 0.62, 95% CI 0.43-0.90, p=0.01). These two polymorphisms fully explained the risk estimates of all haplotypes. Individual haplotypes, however, were not significantly associated with xanthomas. CONCLUSION: Variants in the ALOX5AP gene are associated with the presence of xanthomas in FH patients. This result supports our hypothesis that inflammation is a pathogenetic factor of xanthomas.

Usefulness of genetic polymorphisms and conventional risk factors to predict coronary heart disease in patients with familial hypercholesterolemia.

Familial hypercholesterolemia (FH) is an autosomal dominant disorder with an associated high risk of coronary heart disease (CHD). The considerable variation in age of onset of CHD in patients with FH is believed to arise from conventional risk factors, as well as genetic variation other than in the low-density lipoprotein receptor gene. The degree to which currently known genetic variants can improve the prediction of CHD risk beyond conventional risk factors in this disorder was investigated. Fourteen genetic variants recently identified for association with CHD in a Dutch FH population were considered. Prediction models were constructed using Cox proportional hazards models, and predictive value was assessed using a concordance statistic (c statistic). A total of 1,337 patients with FH were completely genotyped for all genetic variants. Hazard ratios of the genetic variants ranged from 0.61 to 0.74 and 1.24 to 2.33. The c statistic of the CHD prediction model based on genetic variants was 0.59, denoting little discrimination. The model based on conventional risk factors had a c statistic of 0.75, denoting moderate discrimination. Adding genetic test results to this model increased the c statistic to 0.76. In conclusion, the contribution of 14 genetic variants to the prediction of CHD risk in patients with FH was limited. To improve genome-based prediction of CHD, larger numbers of genetic variants need to be identified that either on their own or in gene-gene interaction have substantial effects on CHD risk.

ABCG8 gene polymorphisms, plasma cholesterol concentrations, and risk of cardiovascular disease in familial hypercholesterolemia.

Elevated plasma plant sterol concentrations may be a risk factor of cardiovascular disease (CVD). Polymorphisms in the ABCG8 gene have been identified that contribute to the variation in plasma concentrations of plant sterols. However, data on the direct relationship of ABCG8 gene polymorphisms with CVD are lacking. Therefore, we examined associations between the D19H and T400K polymorphisms in the ABCG8 gene and CVD in a large cohort study of 2012 patients with heterozygous familial hypercholesterolemia (FH). A total of 244 individuals carried one or two alleles of the D19H variant and 568 individuals the T400K variant. During 94,809 person years, 648 (32.2%) individuals developed CVD of which coronary heart disease (CHD) was the most frequent cardiovascular event (N=553). In a Cox proportional hazard regression model adjusted for relevant cardiovascular risk factors, the D19H polymorphism was not associated with total CVD risk (p=0.2), but there was evidence of an association with higher risk of CHD (RR 1.42, CI 1.04-1.95; p=0.03). We observed no relationship between the T400K polymorphism and cardiovascular endpoints (p>0.1). However, FH individuals carrying the risk genotype for both ABCG8 variants had an increased risk of CVD (RR 1.57, 95% CI 1.13-2.18; p=0.01) and CHD (RR 1.72, 95% CI 1.23-2.41; p=0.002). In conclusion, our data suggest that genetic variation in the ABCG8 gene may influence the burden of atherosclerosis.

Arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene and coronary heart disease risk in familial hypercholesterolemia.

OBJECTIVES: To investigate the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene as a potential modifier gene for coronary heart disease (CHD) in patients with familial hypercholesterolemia (FH). BACKGROUND: The ALOX5AP gene is required for the synthesis of leukotrienes, a protein family involved in inflammatory responses. Recently, genetic variation in this gene was shown to be associated with myocardial infarction in an Icelandic and British population. Since FH is characterized by severely increased levels of plasma low-density lipoprotein (LDL) cholesterol levels, chronic inflammation of the arterial wall, and subsequent premature CHD, the ALOX5AP gene could be an important modifier gene for CHD in FH. METHODS: In a cohort of 1817 FH patients, we reconstructed two four-marker haplotypes, previously defined in Icelandic (HapA) and British (HapB) individuals. The haplotypes were inferred with PHASE and the associations between the haplotypes and CHD were analyzed with a Cox proportional hazards model, adjusted for year of birth, sex, and smoking. RESULTS: HapB had a frequency of 6.9% and 8.2% in the group without and with CHD, respectively, conferring a hazard ratio of 1.48 (95% CI 1.17-1.89, p=0.001). This association was predominantly found in patients with LDL cholesterol levels above the median (HR 1.82, 95% CI 1.20-2.76, p=0.005). HapA was not associated with CHD. CONCLUSION: We conclude that genetic variation in the ALOX5AP gene contributes to CHD risk in patients with FH. Our findings emphasize the important role of inflammation in the pathogenesis of early CHD in this disorder, particularly in patients with more severely raised LDL cholesterol levels.