High relative amount of nodular calcification in femoral plaques is associated with milder lower extremity arterial disease.

BACKGROUND: Clinical implications of different types of vascular calcification are poorly understood. The two most abundant forms of calcification, nodular and sheet calcification, have not been quantitatively analyzed in relation to the clinical presentation of lower extremity arterial disease (LEAD). METHODS: The study analyzed 51 femoral artery plaques collected during femoral endarterectomy, characterized by the presence of > 90% stenosis. Comprehensive clinical data was obtained from patient records, including magnetic resonance angiography (MRA) images, toe pressure and ankle brachial index measurements and laboratory values. The plaques were longitudinally sectioned, stained with Hematoxylin and Eosin and digitized in a deep learning platform for quantification of the relative area of nodular and sheet calcification to the plaque section area. A deep learning artificial intelligence algorithm was designed and independently validated to reliably quantify nodular calcification and sheet calcification. Vessel measurements and quantity of each calcification category was compared to the risk factors and clinical presentation. RESULTS: On average, > 90% stenosed vessels contained 22.4 ± 12.3% of nodular and 14.5 ± 11.8% of sheet calcification. Nodular calcification area proportion in lesions with > 90% stenosis is associated with reduced risk of critically low toe pressure (< 30 mmHg) (OR = 0.910, 95% CI = 0.835-0.992, p < 0.05), severely lowered ankle brachial index (< 0.4) (OR = 0.912, 95% CI = 0.84-0.986, p < 0.05), and semi-urgent operation (OR = 0.882, 95% CI = 0.797-0.976, p < 0.05). Sheet calcification did not show any significant association. CONCLUSIONS: Large amount of nodular calcification is associated with less severe LEAD. Patients with nodular calcification may have better flow reserves despite local obstruction.

Susceptibility of low-density lipoprotein particles to aggregate depends on particle lipidome, is modifiable, and associates with future cardiovascular deaths.

Aims: Low-density lipoprotein (LDL) particles cause atherosclerotic cardiovascular disease (ASCVD) through their retention, modification, and accumulation within the arterial intima. High plasma concentrations of LDL drive this disease, but LDL quality may also contribute. Here, we focused on the intrinsic propensity of LDL to aggregate upon modification. We examined whether inter-individual differences in this quality are linked with LDL lipid composition and coronary artery disease (CAD) death, and basic mechanisms for plaque growth and destabilization. Methods and results: We developed a novel, reproducible method to assess the susceptibility of LDL particles to aggregate during lipolysis induced ex vivo by human recombinant secretory sphingomyelinase. Among patients with an established CAD, we found that the presence of aggregation-prone LDL was predictive of future cardiovascular deaths, independently of conventional risk factors. Aggregation-prone LDL contained more sphingolipids and less phosphatidylcholines than did aggregation-resistant LDL. Three interventions in animal models to rationally alter LDL composition lowered its susceptibility to aggregate and slowed atherosclerosis. Similar compositional changes induced in humans by PCSK9 inhibition or healthy diet also lowered LDL aggregation susceptibility. Aggregated LDL in vitro activated macrophages and T cells, two key cell types involved in plaque progression and rupture. Conclusion: Our results identify the susceptibility of LDL to aggregate as a novel measurable and modifiable factor in the progression of human ASCVD.

Chromosome X-wide association study identifies Loci for fasting insulin and height and evidence for incomplete dosage compensation.

The X chromosome (chrX) represents one potential source for the "missing heritability" for complex phenotypes, which thus far has remained underanalyzed in genome-wide association studies (GWAS). Here we demonstrate the benefits of including chrX in GWAS by assessing the contribution of 404,862 chrX SNPs to levels of twelve commonly studied cardiometabolic and anthropometric traits in 19,697 Finnish and Swedish individuals with replication data on 5,032 additional Finns. By using a linear mixed model, we estimate that on average 2.6% of the additive genetic variance in these twelve traits is attributable to chrX, this being in proportion to the number of SNPs in the chromosome. In a chrX-wide association analysis, we identify three novel loci: two for height (rs182838724 near FGF16/ATRX/MAGT1, joint P-value = 2.71×10(-9), and rs1751138 near ITM2A, P-value = 3.03×10(-10)) and one for fasting insulin (rs139163435 in Xq23, P-value = 5.18×10(-9)). Further, we find that effect sizes for variants near ITM2A, a gene implicated in cartilage development, show evidence for a lack of dosage compensation. This observation is further supported by a sex-difference in ITM2A expression in whole blood (P-value = 0.00251), and is also in agreement with a previous report showing ITM2A escapes from X chromosome inactivation (XCI) in the majority of women. Hence, our results show one of the first links between phenotypic variation in a population sample and an XCI-escaping locus and pinpoint ITM2A as a potential contributor to the sexual dimorphism in height. In conclusion, our study provides a clear motivation for including chrX in large-scale genetic studies of complex diseases and traits.

Plasma ceramides predict cardiovascular death in patients with stable coronary artery disease and acute coronary syndromes beyond LDL-cholesterol.

AIMS: The aim was to study the prognostic value of plasma ceramides (Cer) as cardiovascular death (CV death) markers in three independent coronary artery disease (CAD) cohorts. METHODS AND RESULTS: Corogene study is a prospective Finnish cohort including stable CAD patients (n = 160). Multiple lipid biomarkers and C-reactive protein were measured in addition to plasma Cer(d18:1/16:0), Cer(d18:1/18:0), Cer(d18:1/24:0), and Cer(d18:1/24:1). Subsequently, the association between high-risk ceramides and CV mortality was investigated in the prospective Special Program University Medicine-Inflammation in Acute Coronary Syndromes (SPUM-ACS) cohort (n = 1637), conducted in four Swiss university hospitals. Finally, the results were validated in Bergen Coronary Angiography Cohort (BECAC), a prospective Norwegian cohort study of stable CAD patients. Ceramides, especially when used in ratios, were significantly associated with CV death in all studies, independent of other lipid markers and C-reactive protein. Adjusted odds ratios per standard deviation for the Cer(d18:1/16:0)/Cer(d18:1/24:0) ratio were 4.49 (95% CI, 2.24-8.98), 1.64 (1.29-2.08), and 1.77 (1.41-2.23) in the Corogene, SPUM-ACS, and BECAC studies, respectively. The Cer(d18:1/16:0)/Cer(d18:1/24:0) ratio improved the predictive value of the GRACE score (net reclassification improvement, NRI = 0.17 and ΔAUC = 0.09) in ACS and the predictive value of the Marschner score in stable CAD (NRI = 0.15 and ΔAUC = 0.02). CONCLUSIONS: Distinct plasma ceramide ratios are significant predictors of CV death both in patients with stable CAD and ACS, over and above currently used lipid markers. This may improve the identification of high-risk patients in need of more aggressive therapeutic interventions.

Genetic support for the causal role of insulin in coronary heart disease.

AIMS/HYPOTHESIS: Epidemiological studies have identified several traits associated with CHD, but few of these have been shown to be causal risk factors and thus suitable targets for treatment. Our aim was to evaluate the causal role of a large set of known CHD risk factors using single-nucleotide polymorphisms (SNPs) as instrumental variables. METHODS: Based on published genome-wide association studies (GWASs), we estimated the associations between the established risk factors (blood lipids, obesity, glycaemic traits and BP) and CHD with two complementary approaches: (1) using summary statistics from GWASs to analyse the accordance of SNP effects on risk factors and on CHD; and (2) individual-level analysis where we constructed genetic risk scores (GRSs) in a large Finnish dataset (N = 26,554, CHD events n = 4016). We used a weighted regression-based method for summary-level data to evaluate the causality of risk factors. The associations between the GRSs and CHD in the Finnish dataset were evaluated with logistic and conditional logistic regression models. RESULTS: The summary-level data analysis revealed causal effects between glycaemic traits (insulin and glucose) and CHD. The individual-level data analysis supported the causal role of insulin, but not of glucose, on CHD. The GRS for insulin was associated with CHD in the Finnish cohort (OR 1.06 per SD in GRS, 95% CI 1.02, 1.10, p = 0.002). CONCLUSIONS/INTERPRETATION: These results support the causal role of insulin in the pathogenesis of CHD. Efficient treatment and prevention of insulin resistance is essential to prevent future CHD events.

Novel Associations Between Major Histocompatibility Complex and Pediatric-onset Inflammatory Bowel Disease.

PURPOSE: Major histocompatibility complex (MHC) genes have been widely studied in adult inflammatory bowel disease (IBD), but data on MHC genes are scarce in pediatric IBD. This study focused on MHC association of genes with pediatric-onset IBD and its different phenotypes. METHODS: Blood samples of 103 patients with pediatric IBD (Crohn disease or ulcerative colitis) were collected at Children's Hospital, University of Helsinki, Finland. HLA-A, -B, -DRB1 alleles and complement C4A and C4B gene copy numbers were determined and constructed into haplotypes by a Bayesian algorithm (PHASE). A general population cohort (n = 149) served as a control. HLA-alleles and C4 deficiency frequencies were compared between patients and controls with χ-squared and Fisher exact test with Bonferroni correction (Pcorr). RESULTS: One MHC haplotype HLA-A03; HLA-B07; 1 C4A gene; 1 C4B gene; HLA-DRB115 was more common in Crohn disease and ulcerative colitis than in controls (7/61, 11.5%, 6/42, 14.3% and 1/149, 0.7%, respectively, odds ratio (OR) = 19.19, 95% CI 2.31-159.57, Pcorr = 0.004 for Crohn disease vs controls and OR = 24.67, 95% CI 2.88-211.36, Pcorr = 0.002 for ulcerative colitis vs controls). Two MHC markers were associated with clinical characteristics. HLA-DRB101 was more common in patients with milder disease course, that is, no need for anti-tumor necrosis factor (TNF)-α medication (18/32, 56.2% vs 19/71, 26.8% without and with anti-TNF-α medication, respectively, OR = 0.28, 95% CI 0.12-0.68, Pcorr = 0.032). C4B deficiency (<2 C4B genes) was associated with complicated recovery after surgery (12/16, 75.0% vs 4/16, 25.0%, respectively, OR = 9.00, 95% CI 1.82-44.59, Pcorr = 0.025). CONCLUSIONS: One MHC haplotype is strongly linked with pediatric-onset IBD, whereas the need for immunomodulatory therapy and surgery outcome associates with other distinct MHC gene markers.

Genetic variation on the BAT1-NFKBIL1-LTA region of major histocompatibility complex class III associates with periodontitis.

Periodontitis is a chronic inflammatory disease with a multifactorial etiology. We investigated whether human major histocompatibility complex (MHC) polymorphisms (6p21.3) are associated with periodontal parameters. Parogene 1 population samples (n = 169) were analyzed with 13,245 single nucleotide polymorphisms (SNPs) of the MHC region. Eighteen selected SNPs (P ≤ 0.001) were replicated in Parogene 2 population samples (n = 339) and the Health 2000 Survey (n = 1,420). All subjects had a detailed clinical and radiographic oral health examination. Serum lymphotoxin-α (LTA) concentrations were measured in the Parogene populations, and the protein was detected in inflamed periodontal tissue. In the Parogene 1 population, 10 SNPs were associated with periodontal parameters. The strongest associations emerged from the parameters bleeding on probing (BOP) and a probing pocket depth (PPD) of ≥6 mm with the genes BAT1, NFKBIL1, and LTA. Six SNPs, rs11796, rs3130059, rs2239527, rs2071591, rs909253, and rs1041981 (r(2), ≥0.92), constituted a risk haplotype. In the Parogene 1 population, the haplotype had the strongest association with the parameter BOP, a PPD of ≥6 mm, and severe periodontitis with odds ratios (95% confidence intervals) of 2.63 (2.21 to 3.20), 2.90 (2.37 to 3.52), and 3.10 (1.63 to 5.98), respectively. These results were replicated in the other two populations. High serum LTA concentrations in the Parogene population were associated with the periodontitis risk alleles of the LTA SNPs (rs909253 and rs1041981) of the haplotype. In addition, the protein was expressed in inflamed gingival connective tissue. We identified a novel BAT1-NFKBIL1-LTA haplotype as a significant contributor to the risk of periodontitis. The genetic polymorphisms in the MHC class III region may be functionally important in periodontitis susceptibility.

Genome-wide meta-analysis of common variant differences between men and women.

The male-to-female sex ratio at birth is constant across world populations with an average of 1.06 (106 male to 100 female live births) for populations of European descent. The sex ratio is considered to be affected by numerous biological and environmental factors and to have a heritable component. The aim of this study was to investigate the presence of common allele modest effects at autosomal and chromosome X variants that could explain the observed sex ratio at birth. We conducted a large-scale genome-wide association scan (GWAS) meta-analysis across 51 studies, comprising overall 114 863 individuals (61 094 women and 53 769 men) of European ancestry and 2 623 828 common (minor allele frequency >0.05) single-nucleotide polymorphisms (SNPs). Allele frequencies were compared between men and women for directly-typed and imputed variants within each study. Forward-time simulations for unlinked, neutral, autosomal, common loci were performed under the demographic model for European populations with a fixed sex ratio and a random mating scheme to assess the probability of detecting significant allele frequency differences. We do not detect any genome-wide significant (P < 5 × 10(-8)) common SNP differences between men and women in this well-powered meta-analysis. The simulated data provided results entirely consistent with these findings. This large-scale investigation across ~115 000 individuals shows no detectable contribution from common genetic variants to the observed skew in the sex ratio. The absence of sex-specific differences is useful in guiding genetic association study design, for example when using mixed controls for sex-biased traits.

Plasma HDL cholesterol and risk of myocardial infarction: a mendelian randomisation study.

BACKGROUND: High plasma HDL cholesterol is associated with reduced risk of myocardial infarction, but whether this association is causal is unclear. Exploiting the fact that genotypes are randomly assigned at meiosis, are independent of non-genetic confounding, and are unmodified by disease processes, mendelian randomisation can be used to test the hypothesis that the association of a plasma biomarker with disease is causal. METHODS: We performed two mendelian randomisation analyses. First, we used as an instrument a single nucleotide polymorphism (SNP) in the endothelial lipase gene (LIPG Asn396Ser) and tested this SNP in 20 studies (20,913 myocardial infarction cases, 95,407 controls). Second, we used as an instrument a genetic score consisting of 14 common SNPs that exclusively associate with HDL cholesterol and tested this score in up to 12,482 cases of myocardial infarction and 41,331 controls. As a positive control, we also tested a genetic score of 13 common SNPs exclusively associated with LDL cholesterol. FINDINGS: Carriers of the LIPG 396Ser allele (2·6% frequency) had higher HDL cholesterol (0·14 mmol/L higher, p=8×10(-13)) but similar levels of other lipid and non-lipid risk factors for myocardial infarction compared with non-carriers. This difference in HDL cholesterol is expected to decrease risk of myocardial infarction by 13% (odds ratio [OR] 0·87, 95% CI 0·84-0·91). However, we noted that the 396Ser allele was not associated with risk of myocardial infarction (OR 0·99, 95% CI 0·88-1·11, p=0·85). From observational epidemiology, an increase of 1 SD in HDL cholesterol was associated with reduced risk of myocardial infarction (OR 0·62, 95% CI 0·58-0·66). However, a 1 SD increase in HDL cholesterol due to genetic score was not associated with risk of myocardial infarction (OR 0·93, 95% CI 0·68-1·26, p=0·63). For LDL cholesterol, the estimate from observational epidemiology (a 1 SD increase in LDL cholesterol associated with OR 1·54, 95% CI 1·45-1·63) was concordant with that from genetic score (OR 2·13, 95% CI 1·69-2·69, p=2×10(-10)). INTERPRETATION: Some genetic mechanisms that raise plasma HDL cholesterol do not seem to lower risk of myocardial infarction. These data challenge the concept that raising of plasma HDL cholesterol will uniformly translate into reductions in risk of myocardial infarction. FUNDING: US National Institutes of Health, The Wellcome Trust, European Union, British Heart Foundation, and the German Federal Ministry of Education and Research.

Prolonged myalgia in Sindbis virus infection: case description and in vitro infection of myotubes and myoblasts.

BACKGROUND: Sindbis virus (SINV) is a mosquito-borne alphavirus found in Eurasia, Africa, and Oceania. Clinical SINV infection is characterized by febrile rash and arthritis and sometimes prolonged arthralgia and myalgia. The pathophysiological mechanisms of musculoskeletal and rheumatic disease caused by SINV are inadequately understood. METHODS: We studied the muscle pathology of SINV infection ex vivo by examining a unique muscle biopsy obtained from a patient with chronic myalgia and arthralgia 6 months after acute SINV infection and assessed potential genetic predisposing factors by determining the human leukocyte antigen (HLA) and complement factor C4 genes and proteins. In addition, we performed in vitro SINV infections of primary human myoblasts and myotubes. RESULTS: In the muscle biopsy we found evidence of muscle regeneration due to previous necrotic lesions likely caused by earlier SINV infection. We showed that human myoblasts and myotubes were susceptible in vitro for SINV infection as the cells became immunoreactive for viral antigens and cytopathic effect was observed. The patient was homozygous for HLA-B*35 alleles and heterozygous for HLA-DRB1*01 and HLA-DRB1*03 alleles and had total deficiency of C4B protein. CONCLUSIONS: This study provides new insights concerning pathological processes leading to chronic symptoms in SINV infection and demonstrates for the first time the susceptibility of human myogenic cells to SINV infection.

The Novel Ceramide- and Phosphatidylcholine-Based Risk Score for the Prediction of New-Onset of Hypertension.

Ceramides and other sphingolipids are implicated in vascular dysfunction and inflammation. They have been suggested as potential biomarkers for hypertension. However, their specific association with hypertension prevalence and onset requires further investigation. This study aimed to identify specific ceramide and phosphatidylcholine species associated with hypertension prevalence and onset. The 2002 FINRISK (Finnish non-communicable risk factor survey) study investigated the association between coronary event risk scores (CERT1 and CERT2) and hypertension using prevalent and new-onset hypertension groups, both consisting of 7722 participants, over a span of 10 years. Ceramide and phosphatidylcholine levels were measured using tandem liquid chromatography-mass spectrometry. Ceramide and phosphatidylcholine ratios, including ceramide (d18:1/18:0), ceramide (d18:1/24:1), phosphatidylcholine (16:0/16:0), and the ratio of ceramide (d18:1/18:0)/(d18:1/16:0), are consistently associated with both prevalence and new-onset hypertension. Ceramide (d18:1/24:0) was also linked to both hypertension measures. Adjusting for covariates, CERT1 and CERT2 showed no-longer-significant associations with hypertension prevalence, but only CERT2 predicted new-onset hypertension. Plasma ceramides and phosphatidylcholines are crucial biomarkers for hypertension, with imbalances potentially contributing to its development. Further research is needed to understand the underlying mechanisms by which ceramides will contribute to the development of hypertension.

Clinical Sindbis alphavirus infection is associated with HLA-DRB1*01 allele and production of autoantibodies.

BACKGROUND: Sindbis virus (SINV) is a mosquito-borne alphavirus found in Eurasia, Africa, and Oceania. Clinical SINV infection, characterized by arthropathic disease that may persist for years, is primarily reported in Northern Europe where the disease has considerable public health importance in endemic areas. The aim of this study was to investigate the role of genetic factors in the susceptibility and outcome of SINV infection and to elucidate the association between SINV infection and autoimmunity. METHODS: The study included 49 patients with serologically confirmed symptomatic SINV infection who were followed for 3 years after acute infection. Human leukocyte antigen (HLA) genes known to be associated with rheumatic and infectious diseases and complement C4 genes were determined in 35 patients. Furthermore, a set of autoantibodies was measured at the acute phase and 3 years after infection in 44 patients. RESULTS: The frequency of DRB1*01 was significantly higher among patients with SINV infection than in the reference population (odds ratio, 3.3; 95% confidence interval, 1.7-6.5; P = .003). The DRB1*01 allele was particularly frequent in patients who at 3 years postinfection experienced joint manifestations. The frequency of rheumatoid factor at 3 years postinfection was 29.5% and had increased significantly (P = .02) during the 3-year period. In addition, antinuclear and antimitochondrial antibodies were present in serum 3 years postinfection with frequencies of 15.9% and 6.8%, respectively. CONCLUSIONS: Our data show that symptomatic SINV infection is associated with the HLA system and that autoantibody titers are elevated in patients 3 years postinfection. These findings indicate that SINV-induced arthritis shares features with autoimmune diseases.

A multilocus genetic risk score for coronary heart disease: case-control and prospective cohort analyses.

BACKGROUND: Comparison of patients with coronary heart disease and controls in genome-wide association studies has revealed several single nucleotide polymorphisms (SNPs) associated with coronary heart disease. We aimed to establish the external validity of these findings and to obtain more precise risk estimates using a prospective cohort design. METHODS: We tested 13 recently discovered SNPs for association with coronary heart disease in a case-control design including participants differing from those in the discovery samples (3829 participants with prevalent coronary heart disease and 48,897 controls free of the disease) and a prospective cohort design including 30,725 participants free of cardiovascular disease from Finland and Sweden. We modelled the 13 SNPs as a multilocus genetic risk score and used Cox proportional hazards models to estimate the association of genetic risk score with incident coronary heart disease. For case-control analyses we analysed associations between individual SNPs and quintiles of genetic risk score using logistic regression. FINDINGS: In prospective cohort analyses, 1264 participants had a first coronary heart disease event during a median 10·7 years' follow-up (IQR 6·7-13·6). Genetic risk score was associated with a first coronary heart disease event. When compared with the bottom quintile of genetic risk score, participants in the top quintile were at 1·66-times increased risk of coronary heart disease in a model adjusting for traditional risk factors (95% CI 1·35-2·04, p value for linear trend=7·3×10(-10)). Adjustment for family history did not change these estimates. Genetic risk score did not improve C index over traditional risk factors and family history (p=0·19), nor did it have a significant effect on net reclassification improvement (2·2%, p=0·18); however, it did have a small effect on integrated discrimination index (0·004, p=0·0006). Results of the case-control analyses were similar to those of the prospective cohort analyses. INTERPRETATION: Using a genetic risk score based on 13 SNPs associated with coronary heart disease, we can identify the 20% of individuals of European ancestry who are at roughly 70% increased risk of a first coronary heart disease event. The potential clinical use of this panel of SNPs remains to be defined. FUNDING: The Wellcome Trust; Academy of Finland Center of Excellence for Complex Disease Genetics; US National Institutes of Health; the Donovan Family Foundation.

Assessment of complement C4 gene copy number using the paralog ratio test.

The complement C4 locus is in the class III region of the MHC, and exhibits copy number variation. Complement C4 null alleles have shown association with a number of diseases including systemic lupus erythematosus (SLE). However, most studies to date have used protein immunophenotyping and not direct interrogation of the genome to determine C4 null allele status. Moreover, a lack of accurate C4 gene copy number (GCN) estimation and tight linkage disequilibrium across the disease-associated MHC haplotypes has confounded attempts to establish whether or not these associations are causal. We have therefore developed a high throughput paralog ratio test (PRT) in association with two restriction enzyme digest variant ratio tests (REDVRs) to determine total C4 GCN, C4A GCN, and C4B GCN. In the densely genotyped CEU cohort we show that this method is accurate and reproducible when compared to gold standard Southern blot copy number estimation with a discrepancy rate of 9%. We find a broad range of C4 GCNs in the CEU and the 1958 British Birth Cohort populations under study. In addition, SNP-C4 CNV analyses show only moderate levels of correlation and therefore do not support the use of SNP genotypes as proxies for complement C4 GCN.

Osteoid Metaplasia in Femoral Artery Plaques Is Associated With the Clinical Severity of Lower Extremity Artery Disease in Men.

Lamellar metaplastic bone, osteoid metaplasia (OM), is found in atherosclerotic plaques, especially in the femoral arteries. In the carotid arteries, OM has been documented to be associated with plaque stability. This study investigated the clinical impact of OM load in femoral artery plaques of patients with lower extremity artery disease (LEAD) by using a deep learning-based image analysis algorithm. Plaques from 90 patients undergoing endarterectomy of the common femoral artery were collected and analyzed. After decalcification and fixation, 4-µm-thick longitudinal sections were stained with hematoxylin and eosin, digitized, and uploaded as whole-slide images on a cloud-based platform. A deep learning-based image analysis algorithm was trained to analyze the area percentage of OM in whole-slide images. Clinical data were extracted from electronic patient records, and the association with OM was analyzed. Fifty-one (56.7%) sections had OM. Females with diabetes had a higher area percentage of OM than females without diabetes. In male patients, the area percentage of OM inversely correlated with toe pressure and was significantly associated with severe symptoms of LEAD including rest pain, ulcer, or gangrene. According to our results, OM is a typical feature of femoral artery plaques and can be quantified using a deep learning-based image analysis method. The association of OM load with clinical features of LEAD appears to differ between male and female patients, highlighting the need for a gender-specific approach in the study of the mechanisms of atherosclerotic disease. In addition, the role of plaque characteristics in the treatment of atherosclerotic lesions warrants further consideration in the future.

Recurrent lymphocytic meningitis positive for herpes simplex virus type 2.

We found the prevalence of recurrent lymphocytic meningitis associated with herpes simplex virus type 2 (HSV-2) was 2.2/100,000 population in Finland during 1996-2006, higher than previous estimates. PCR was most sensitive in detecting HSV-2 DNA from cerebrospinal fluid if the sample was taken 2-5 days after symptom onset.

Beneficial effect of clarithromycin in patients with acute coronary syndrome and complement C4 deficiencies.

OBJECTIVES: We sought to examine the role of complement component C4 deficiencies on the effect of antibiotic treatment in patients with acute coronary syndrome (ACS). DESIGN: Patients with ACS (n=144) were randomly divided to receive a three-month treatment of clarithromycin or placebo and followed for major adverse coronary and cerebrovascular events (MACCEs) for 404.5 median days (range 138-924 days). The primary results indicated that clarithromycin prevented recurrent cardiovascular attacks. For the present study we performed serum C4 allotyping of C4A and C4B. The clarithromycin response was reanalyzed taking into account the deficiencies in the C4 allotypes. RESULTS: The prevalence of C4A deficiency, C4B deficiency or these combined were 29.2% (42/144), 39.6% (57/144) and 66.0% (95/144), respectively. In patients with C4 deficiencies clarithromycin treatment resulted in a reduced number of MACCEs and the best cumulative survival as compared with the placebo group (MACCE 18.8% versus 39.1%, respectively; Log rank test, p=0.015). CONCLUSIONS: Only patients with ACS and C4 deficiencies seem to benefit from antibiotic treatment. This may explain the controversial results of secondary prevention trials of coronary artery disease and possibly serve as a pharmacogenomic marker for clarithromycin treatment.

The complexity and diversity of major histocompatibility complex challenge disease association studies.

The major histocompatibility complex (MHC; 6p21.3) contains the most polymorphic genes, the most gene dense parts, and the highest diversity of functional gene clusters of the human genome. The clusters form haplotypes, which differ in linkage disequilibrium and show large variations in strength and extent between populations. Haplotype cis- and trans-expression quantitative trait loci have increased the knowledge of regulatory interactions between multiple MHC genes. The detailed haplotype data offer a reference for future studies in immune-mediated diseases and may unravel disease associations in conditions traditionally considered not to be immunologic. This article aims to describe the structural and functional variations of the MHC genes and haplotypes and their role on selected immune-mediated diseases. In immune-/inflammation-mediated complex diseases, hundreds of common variants influence the development of the disease trait, but the individual variants have small effects on the disease phenotypes as seen in genome-wide association studies. The genetic influence may still be significant on the cellular or molecular level. Nonetheless, the HLA alone is not sufficient as a susceptible genetic background to deduce the disease. For a comprehensive insight of the disease mechanisms, both immunological and genome assays methods are required.

Exome Sequencing Identifies Susceptibility Loci for Sarcoidosis Prognosis.

Many sarcoidosis-associating immunological genes have been shown to be shared between other immune-mediated diseases. In Finnish sarcoidosis patients, good prognosis subjects more commonly have HLA-DRB1*03:01 and/or HLA-DRB1*04:01-DPB1*04:01 haplotype, but no marker for persistent disease have been found. The objective was to further pinpoint genetic differences between prognosis subgroups in relation to the HLA markers. Whole-exome sequencing was conducted for 72 patients selected based on disease activity (resolved disease, n = 36; persistent disease, n = 36). Both groups were further divided by the HLA markers (one/both markers, n = 18; neither of the markers, n = 18). The Finnish exome data from the Genome Aggregation Database was used as a control population in the WES sample. Statistical analyses included single-variant analysis for common variants and gene level analysis for rare variants. We attempted to replicate associated variants in 181 Finnish sarcoidosis patients and 150 controls. An association was found in chromosome 1p36.21 (AADACL3 and C1orf158), which has recently been associated with sarcoidosis in another WES study. In our study, variations in these genes were associated with resolved disease (AADACL3, p = 0.0001 and p = 0.0003; C1orf158, p = 7.03E-05). Another interesting chromosomal region also peaked, Leucocyte Receptor Complex in 19q13.42, but the association diminished in the replication sample. In conclusion, this WES study supports the previously found association in the region 1p36.21. Furthermore, a novel to sarcoidosis region was found, but additional studies are warranted to verify this association.