Endothelial nitric oxide synthase gene polymorphisms in giant cell arteritis

Current Insights into Tissue Injury of Giant Cell Arteritis: From Acute Inflammatory Responses towards Inappropriate Tissue Remodeling

Giant cell arteritis (GCA) is an autoimmune disease affecting large vessels in patients over 50 years old. It is an exemplary model of a classic inflammatory disorder with IL-6 playing the leading role. The main comorbidities that may appear acutely or chronically are vascular occlusion leading to blindness and thoracic aorta aneurysm formation, respectively. The tissue inflammatory bulk is expressed as acute or chronic delayed-type hypersensitivity reactions, the latter being apparent by giant cell formation. The activated monocytes/macrophages are associated with pronounced Th1 and Th17 responses. B-cells and neutrophils also participate in the inflammatory lesion. However, the exact order of appearance and mechanistic interactions between cells are hindered by the lack of cellular and molecular information from early disease stages and accurate experimental models. Recently, senescent cells and neutrophil extracellular traps have been described in tissue lesions. These structures can remain in tissues for a prolonged period, potentially favoring inflammatory responses and tissue remodeling. In this review, current advances in GCA pathogenesis are discussed in different inflammatory phases. Through the description of these-often overlapping-phases, cells, molecules, and small lipid mediators with pathogenetic potential are described.

Mechanism and biomarkers in aortitis--a review

Aortitis can be the manifestation of an underlying infectious or noninfectious disease process. An autoimmune cause is suggested in a large proportion of noninfectious causes. Similar to other autoimmune diseases, the pathophysiology of aortitis has been investigated in detail, but the etiology remains unknown. Most cases of aortitis often go undetected for a long time and are often identified at late stages of the disease. Recent advances in imaging techniques have significantly improved the diagnosis of aortitis. However, significant challenges associated with the imaging techniques limit their use. Several routine inflammation-based markers, such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and inflammatory cytokines, are nonspecific and, therefore, have limited use in the diagnosis of aortitis. The search for more specific serum biomarkers, which can facilitate detection and progression is under progress. Several autoantibodies have been identified, but assigning their role in the pathogenesis as well as their specificity remains a challenge. The current review addresses some of these issues in detail. KEY MESSAGES: • Noninfectious aortitis is an autoimmune disease. • Several biomarkers, including cytokines and autoantibodies, are increased in aortitis. • Imaging techniques, commonly used to detect aortitis, are associated with the high cost and technical challenges. • There is a need to develop low-cost biomarker-based detection tools. • The knowledge of biomarkers in aortitis detection is discussed.

Genetic Predispositions of Glucocorticoid Resistance and Therapeutic Outcomes in Polymyalgia Rheumatica and Giant Cell Arteritis

Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are closely related chronic inflammatory diseases. Glucocorticoids (GCs) are first-choice drugs for PMR and GCA, although some patients show poor responsiveness to the initial GC regimen or experience flares after GC tapering. To date, no valid biomarkers have been found to predict which patients are at most risk for developing GC resistance. In this review, we summarize PMR- and GCA-related gene polymorphisms and we associate these gene variants with GC resistance and therapeutic outcomes. A limited number of GC resistance associated-polymorphisms have been published so far, mostly related to HLA-DRB1*04 allele. Other genes such ICAM-1, TLR4 and 9, VEGF, and INFG may play a role, although discrepancies are often found among different populations. We conclude that more studies are required to identify reliable biomarkers of GC resistance. Such biomarkers could help distinguish non-responders from responders to GC treatment, with concomitant consequences for therapeutic strategy.

Giant cell arteritis: pathogenic mechanisms and new potential therapeutic targets

Giant cell arteritis (GCA) is the most common idiopathic systemic vasculitis in persons aged 50 years or greater. Treatment options for GCA, to-date, have been limited and have consisted primarily of glucocorticoids. Significant advances in the understanding of the genetic and cellular mechanisms in GCA are leading to identification of potential pathogenic targets. The recent success of interleukin-6 blockade in the treatment of GCA has opened the landscape to targeted biologic therapy. T cells, particularly T helper 1 and T helper 17 cell lineages have been identified as key inflammatory cells in both active and chronic vascular inflammatory lesions. Therapeutic agents, including abatacept and ustekinumab, which can impede both vasculitogenic cell lines are of particular interest. Inhibition of signalling pathways, including the janus kinase-signal tranducers and activation of transcription (JAK-STAT) and Notch pathways are evolving options. Tocilizumab has shown clear benefit in both newly diagnosed and relapsing patients with GCA and approval of this medication for treatment of GCA has led to rapid incorporation into treatment regimens. More information is required to understand the long-term outcomes of tocilizumab and other investigational targeted therapeutics in the treatment of GCA.

Association of Endothelial Nitric Oxide Synthase Gene Polymorphism with Susceptibility and Nephritis Development of Henoch-Schönlein Purpura in Chinese Han Children

OBJECTIVE

Henoch-Schönlein purpura (HSP) is the most common form of systemic small-vessel vasculitis in children. Previous studies suggested endothelial nitric oxide synthase (eNOS) plays an important role in the pathogenesis and clinical manifestations of HSP. This study aimed to investigate the potential association between 10 single-nucleotide polymorphisms (SNPs) within the eNOS gene and HSP risk and nephritis development in a Chinese Han population.

MATERIALS AND METHODS

A case-control study was conducted including 459 healthy children and 423 children with HSP. SNPs were genotyped by using the MassARRAY system.

RESULTS

The genotypic frequency of rs11771443 was nominally associated with the risk of HSP (p = 0.010), and the C allele significantly increased the risk of HSP (p = 0.003, odds ratio [OR] = 1.331, confidence interval [95% CI] = 1.104-1.605). There was a significant difference in allelic and genotypic distribution of rs1799983 between children with HSP and healthy controls (p = 0.002 and 0.0001, respectively). Strong linkage disequilibrium was observed in two blocks. Significantly fewer T-A-G haplotypes (p = 0.0001, OR = 0.593, 95% CI = 0.448-0.786) were found in children with HSP. No significant association was identified between the 10 SNPs and the pathogenesis of HSP progression to HSP nephritis (HSPN).

CONCLUSIONS

The polymorphisms of eNOS contribute to genetic susceptibility to HSP, but may have no effect on children with HSP progressing to HSPN.

New insights into the pathogenesis of giant cell arteritis and hopes for the clinic

Giant cell arteritis is a complex immune-mediated disease that involves large blood vessels in individuals older than 50 years. Recent studies have confirmed a strong association of this form of vasculitis with the HLA region, particularly with HLA class II genes. However, other non-HLA loci, such as protein tyrosine phosphatase non-receptor type 22, may also account for the susceptibility to giant cell arteritis. In addition, genetic variants located in genes encoding proinflammatory cytokines seem to influence the phenotypic expression of the disease, including the risk of severe ischemic complications, the presence of polymyalgia rheumatica and the higher incidence of relapses observed in some patients. The identification of putative genetic markers of disease severity could have clear therapeutic implications, as it may allow us to identify patients who are potentially responders to specific treatments.

Phagocyte dysfunction in polymyalgia rheumatica and other age-related, chronic, inflammatory conditions

This study was conducted to evaluate phagocyte function in patients with age-related chronic inflammatory conditions. It included 95 patients with PMR, 17 with GCA, 40 with EORA, and 25 age-matched HCs. Serum IL-8 was determined with a bead array. The chemotactic capacity, phagocytic ability, and oxidative burst activity of circulating leukocytes were determined with flow cytometry kits. Patients with active chronic inflammatory diseases showed a significant increase in circulating levels of IL-8 that remained elevated in patients with PMR or EORA, despite treatment. No correlation was found between circulating IL-8 and the migratory capacity of neutrophils. Neutrophils from patients with active EORA without stimulus and after fMLP stimuli showed a higher capacity to migrate than those of the HCs (P=0.033). The phagocytic activity of granulocytes in the patients with GCA was significantly higher than in the HCs and the patients with PMR or EORA (P<0.05). The percentage and MFI of phagocytes that produce ROIs when stimulated with Escherichia coli was significantly reduced in neutrophils and monocytes from the patients with age-restricted inflammatory conditions. We concluded that the effector functions of phagocytes, determined to be chemotaxis, phagocytosis, and oxidative burst, are deregulated in age-restricted inflammatory disorders and may have a pathogenic role.

CC chemokine receptor 5 polymorphism in Italian patients with giant cell arteritis

OBJECTIVES

To evaluate the potential role of CC chemokine receptor 5 (CCR5)Δ32 polymorphism in the susceptibility to giant cell arteritis (GCA) in a cohort of Italian patients.

METHODS

176 consecutive Italian patients with biopsy-proven GCA and 180 healthy age- and sex-matched blood donors were molecularly genotyped for the CCR5Δ32 polymorphism.

RESULTS

No statistically significant difference in the Δ32CCR5 allele frequency between GCA patients (5.1 %) and controls (2.8 %) was observed (p = 0.109). Carriers of the CCR5Δ32 allele (Δ32/Δ32 + CCR5/Δ32) were similarly represented in the two groups.

CONCLUSIONS

Our results do not support a role for the CCR5Δ32 polymorphism in determining susceptibility to GCA.

Endothelial nitric oxide synthase gene intron 4 polymorphism predicts new onset diabetes mellitus after transplantation in kidney allograft recipients treated with cyclosporin A

BACKGROUND

Nitric oxide (NO), synthesized from LS: -arginine by the enzyme endothelial nitric oxide synthase (eNOS), is a potent vasodilator and has been implicated in mediating insulin-induced uptake and metabolism of glucose in skeletal muscle. Polymorphisms of the eNOS gene have been associated with altered eNOS activity and NO levels. Although several factors have been demonstrated for new onset diabetes mellitus after transplantation (NODAT), determining a genetic susceptibility for all patients requires further study. In our study, we evaluated the relationship between eNOS gene intron 4 polymorphism and NODAT in kidney allograft recipients.

METHODS

A total of 82 consecutive patients who received their first kidney transplantation and maintained graft function for at least a 12-month post-transplant period and who used triple therapy including cyclosporin A (CsA) for maintenance immunosuppression were included. PCR-RFLP was used for genetic analyses.

RESULTS

Nine of 82 patients (11%) developed NODAT. Concerning the prevalence of eNOS intron 4 gene polymorphism, a significantly higher percentage of 4a allele carriers developed NODAT than non-carriers [6/26 (23.1%) versus 3/56 (5.4%), P = 0.02]. Compared with non-diabetics, NODAT patients were older (P = 0.04), had higher rate of hepatitis C (P < 0.05) and higher body mass index at the time of transplantation (P = 0.03). In regression analyses, having a 4a allele of the eNOS gene intron 4 polymorphism (P = 0.02) and HCV seropositivity (P = 0.03) were found to be independent risk factors for the development of NODAT.

CONCLUSIONS

These findings suggest that carrying a 4a allele of the eNOS gene intron 4 polymorphism is associated with NODAT. This may help us to further understand the individual risk for development of NODAT in kidney allograft recipients under CsA treatment.

Pathogenesis of giant cell arteritis: More than just an inflammatory condition?

Giant cell arteritis (GCA) is characterized by intimal hyperplasia and luminal obstruction leading to ischemic manifestations involving extra-cranial branches of carotid arteries and aorta. Histopathological lesions involve all layers of the arterial wall and are associated with multinucleated giant cells, fragmented internal elastic lamina and polymorphic cellular infiltrates, including T lymphocytes and macrophages. The pathophysiology of GCA is still poorly understood. After dendritic cell activation, CD4(+) T lymphocytes, T helper 1 (Th1) cells, produce interferon gamma and modulate macrophage activation and functions, and Th17 cells produce interleukin 17 (IL-17), which can induce cytokine production by macrophages and fibroblasts. Macrophages in the adventitia produce pro-inflammatory cytokines such as IL-1, IL-6 and tumor necrosis factor alpha. These cytokines promote arterial wall and systemic inflammation. Questions remain regarding the nature of the antigen(s) triggering dendritic cell activation and the mechanisms underlying vascular remodeling. Here we review recent advances in the pathogenesis of GCA, with emphasis on the interactions between cells of the immune system and components of the vessel wall, including vascular smooth muscle cells and endothelial cells, leading to vascular remodeling. Finally, we propose new areas of investigation that could help understand the triggering factors and key pathogenic events in GCA.

Association between IL-18 gene polymorphisms and biopsy-proven giant cell arteritis

INTRODUCTION

The objective was to investigate the potential implication of the IL18 gene promoter polymorphisms in the susceptibility to giant-cell arteritis (GCA).

METHODS

In total, 212 patients diagnosed with biopsy-proven GCA were included in this study. DNA from patients and matched controls was obtained from peripheral blood. Samples were genotyped for the IL18-137 G>C (rs187238), the IL18-607 C>A (rs1946518), and the IL18-1297 T>C (rs360719) gene polymorphisms with polymerase chain reaction, by using a predesigned TaqMan allele discrimination assay.

RESULTS

No significant association between the IL18-137 G>C polymorphism and GCA was found. However, the IL18 -607 allele A was significantly increased in GCA patients compared with controls (47.8% versus 40.9% in patients and controls respectively; P = 0.02; OR, 1.32; 95% CI, 1.04 to 1.69). It was due to an increased frequency of homozygosity for the IL18 -607 A/A genotype in patients with GCA (20.4%) compared with controls (13.4%) (IL18 -607 A/A versus IL18 -607 A/C plus IL18 -607 C/C genotypes: P = 0.04; OR, 1.59; 95% CI, 1.02 to 2.46). Also, the IL18-1297 allele C was significantly increased in GCA patients (30.7%) compared with controls (23.0%) (P = 0.003; OR, 1.48; 95% CI, 1.13 to 1.95). In this regard, an increased susceptibility to GCA was observed in individuals carrying the IL18-1297 C/C or the IL18-1297 C/T genotypes compared with those carrying the IL18-1297 T/T genotype (IL18-1297 C/C plus IL18-1297 T/C versus IL18-1297 T/T genotype in GCA patients compared with controls: P = 0.005; OR, 1.61; 95% CI, 1.15 to 2.25). We also found an additive effect of the IL18 -1297 and -607 polymorphisms with TLR4 Asp299Gly polymorphism. The OR for GCA was 1.95 for combinations of genotypes with one or two risk alleles, whereas carriers of three or more risk alleles have an OR of 3.7.

CONCLUSIONS

Our results show for the first time an implication of IL18 gene-promoter polymorphisms in the susceptibility to biopsy-proven GCA. In addition, an additive effect between the associated IL18 and TLR4 genetic variants was observed.

Association Between Toll-like Receptor 4 Gene Polymorphism and Biopsy-proven Giant Cell Arteritis

Objective.

Dendritic cells localized at the adventitia-media border of the normal medium-sized arteries play a pivotal role in the initiation of giant cell arteritis (GCA). These cells express a singular surface receptor profile, including a series of Toll-like receptors (TLR). Ligands of TLR-4 promote activation and differentiation of adventitial dendritic cells and are directly implicated in the pathogenesis of GCA. We aimed to assess the potential implication of the TLR4-(+896 A/G) gene polymorphism in the susceptibility to GCA.

Methods.

A total of 210 patients diagnosed with biopsy-proven GCA and 678 matched controls were included in our study. DNA from patients and controls was obtained from peripheral blood. Samples were genotyped for the TLR4-(+896 A/G) (rs4986790) gene polymorphism by polymerase chain reaction, using a predesigned TaqMan allele discrimination assay.

Results.

The TLR4 +896 G allele was significantly increased in biopsy-proven GCA patients compared to controls [p = 0.01; odds ratio (OR) 1.65; 95% confidence interval (CI) 1.08–2.52]. The increase was due to a significantly increased frequency of heterozygosity for the TLR4 −896 A/G genotype in the group of patients with biopsy-proven GCA compared to controls (TLR4 −896 A/G heterozygous in patients with GCA 18.1% compared to 11.4% in controls: p = 0.01; OR 1.72; 95% CI 1.10–2.69). However, no significant differences were observed when patients with GCA were stratified according to the presence of specific clinical features of the disease.

Conclusion.

Our results show for the first time an association of TLR4-(+896 A/G) gene polymorphism with susceptibility to biopsy-proven GCA.

Lack of Association Between STAT4 Gene Polymorphism and Biopsy-proven Giant Cell Arteritis

Objective.

To investigate the potential implication of the STAT4 gene polymorphism rs7574865 in the predisposition to or the clinical expression of giant cell arteritis (GCA).

Methods.

A total of 212 patients diagnosed with biopsy-proven GCA were studied. DNA from patients and controls matched by age, sex, and ethnicity was obtained from peripheral blood. Samples were genotyped for STAT4 rs7574865 polymorphism.

Results.

No statistically significant differences in the allele frequencies for the STAT4 rs7574865 polymorphism were observed between patients and controls. Although we observed an increased frequency of the T/T genotype in GCA patients (6.0%) compared to healthy controls (3.9%), this difference did not achieve statistical significance (OR 1.57, 95% CI 0.72–3.41). No statistically significant differences in allele or genotype frequencies were observed when patients were stratified according to the presence of typical disease features such as polymyalgia rheumatica, severe ischemic manifestations, and visual ischemic complications in the setting of this vasculitis.

Conclusion.

Our results do not support a major role of the STAT4 rs7574865 gene polymorphism in susceptibility to or clinical manifestations of GCA.

C-Reactive Protein Gene Polymorphisms in Biopsy-proven Giant Cell Arteritis from Northwestern Spain

Objective.

To investigate the potential implication of several polymorphisms of the C-reactive protein (CRP) gene in the predisposition to or clinical expression of giant cell arteritis (GCA).

Methods.

A total of 125 patients diagnosed with biopsy-proven GCA and 234 ethnically matched controls from the Lugo region of Northwestern Spain were included in our study. Four functional gene polymorphisms for CRP rs1417938, rs1800947, rs1205, and rs3093059 variants were assessed using a polymerase chain reaction system with predeveloped TaqMan allelic discrimination assay.

Results.

Although we observed a significant increase in the frequency of heterozygotes for rs1417938 A/T [odds ratio (OR) = 1.70; 95% confidence interval (CI) 1.04–2.80; p = 0.03] and rs1205 C/T (OR 1.73; 95% CI 1.07–2.78; p = 0.02) in patients with GCA, no statistically significant differences in the allelic frequencies of these 2 polymorphisms were found between patients with GCA and controls. A marginal significant increase in the frequency of rs3093059 allele T in patients with GCA compared to controls was observed (OR 1.81; 95% CI 0.97–3.39; p = 0.04). However, the increased frequency of patients with GCA homozygous for rs3093059 T/T in patients with GCA compared to controls was out of the range of significance (OR 1.77; 95% CI 0.92–3.40; p = 0.07). No significant differences were found when we stratified patients with GCA according to the presence of polymyalgia rheumatica or severe ischemic complications of the disease.

Conclusion.

The functional CRP gene polymorphisms assessed in our study do not seem to play a major role in the pathogenesis of GCA in individuals from Northwestern Spain.

-463 G/A myeloperoxidase promoter polymorphism in giant cell arteritis

OBJECTIVE

To investigate potential associations between-463 G/A myeloperoxidase (MPO) promoter polymorphism and susceptibility to, and clinical features of giant cell arteritis (GCA).

METHODS

A total of 156 patients with biopsy-proven GCA who were residents of Reggio Emilia, Italy, and 235 population-based controls from the same geographic area were genotyped for-463 G/A promoter polymorphism of the MPO gene by molecular methods. The patients were subgrouped according to the presence or absence of polymyalgia rheumatica and severe ischaemic complications (visual loss and/or cerebrovascular accidents).

RESULTS

The distribution of the MPO-G/A genotype differed significantly between patients with GCA and the controls (p(corr) = 0.003). Allele G was significantly more frequent in patients with GCA than in the controls (p(corr) = 0.0002, OR 2.0, 95% CI 1.4 to 2.9). Homozygosity for the G allele was significantly more frequent in patients with GCA than in controls (p(corr) = 0.0002, OR 2.2, 95% CI 1.4 to 3.4). No significant associations were found when patients with GCA with and without polymyalgia rheumatica or with and without severe ischaemic complications were compared.

CONCLUSIONS

Our findings show that the-463 G/A promoter polymorphism of the MPO gene is associated with GCA susceptibility and support a role for MPO in the pathophysiology of GCA.

Endothelial nitric oxide synthase gene polymorphisms in non-arteritic anterior ischemic optic neuropathy

BACKGROUND

To examine the association between the polymorphisms of the endothelial nitric oxide synthase (eNOS) gene and the occurrence of non-arteritic anterior ischemic optic neuropathy (NAION).

METHODS

We studied 15 patients with NAION (mean age, 62 years; 60% male). We investigated two polymorphisms of the eNOS gene, Glu298Asp polymorphism of exon 7 and T(-786)C polymorphism of the promoter region. The genotype distribution in NAION was compared with the control (mean age, 63 years; 63% male) distribution.

RESULTS

There was no significant difference in the genotype distribution of the Glu298Asp polymorphism between the NAION and control groups (P = 1.000), whereas the genotype dis-tribution of the T(-786)C polymorphism varied significantly between the patients with NAION and control subjects (P = 0.002). After adjusting on covariates, individuals with the CC genotype of the T(-786)C polymorphism were more likely to develop NAION compared with those with TT genotype (odds ratio = 0.09: 95% CI 0.01-0.86).

CONCLUSIONS

We found an increased prevalence of T(-786)C polymorphism of the eNOS gene in patients with NAION. Our data suggest that the T(-786)C polymorphism of the eNOS gene may be an important risk factor in the development of NAION in Japanese subjects.

Association of FCGR2A and FCGR2A-FCGR3A haplotypes with susceptibility to giant cell arteritis

The Fc gamma receptors have been shown to play important roles in the initiation and regulation of many immunological and inflammatory processes and to amplify and refine the immune response to an infection. We have investigated the hypothesis that polymorphism within the FCGR genetic locus is associated with giant cell arteritis (GCA). Biallelic polymorphisms in FCGR2A, FCGR3A, FCGR3B and FCGR2B were examined for association with biopsy-proven GCA (n = 85) and healthy ethnically matched controls (n = 132) in a well-characterised cohort from Lugo, Spain. Haplotype frequencies and linkage disequilibrium (D') were estimated across the FCGR locus and a model-free analysis performed to determine association with GCA. There was a significant association between FCGR2A-131RR homozygosity (odds ratio (OR) 2.10, 95% confidence interval (CI) 1.12 to 3.77, P = 0.02, compared with all others) and carriage of FCGR3A-158F (OR 3.09, 95% CI 1.10 to 8.64, P = 0.03, compared with non-carriers) with susceptibility to GCA. FCGR haplotypes were examined to refine the extent of the association. The haplotype showing the strongest association with GCA susceptibility was the FCGR2A-FCGR3A 131R-158F haplotype (OR 2.84, P = 0.01 for homozygotes compared with all others). There was evidence of a multiplicative joint effect between homozygosity for FCGR2A-131R and HLA-DRB1*04 positivity, consistent with both of these two genetic factors contributing to the risk of disease. The risk of GCA in HLA-DRB1*04 positive individuals homozygous for the FCGR2A-131R allele is increased almost six-fold compared with those with other FCGR2A genotypes who are HLA-DRB1*04 negative. We have demonstrated that FCGR2A may contribute to the 'susceptibility' of GCA in this Spanish population. The increased association observed with a FCGR2A-FCGR3A haplotype suggests the presence of additional genetic polymorphisms in linkage disequilibrium with this haplotype that may contribute to disease susceptibility. These findings may ultimately provide new insights into disease pathogenesis.

Endothelial cell dysfunction in systemic vasculitis: new developments and therapeutic prospects

PURPOSE OF REVIEW

The role of the endothelium as an active player rather than a passive victim of inflammation has received considerable interest in atherosclerosis, but less so in systemic vasculitis (SV). However, the accumulating multi-organ damage seen in SV probably includes the endothelium. Assessment of endothelial function is now a standard clinical research tool in cardio-vascular departments. The exciting insights provided by their application to SV, in both primary disease and connective tissue diseases (CTD), is reviewed here.

RECENT FINDINGS

Diffuse endothelial cell dysfunction (ECD) documented by several techniques occurs commonly in adult and childhood SV. Similar ECD is also seen in CTD. The mechanisms probably relate to inflammatory cytokines such as TNF. The particular role of vasculitic, as opposed to synovial or internal organ inflammation, may be release of secondary mediators directly into the blood stream- whence they can reach distant endothelial beds to induce this diffuse ECD.

SUMMARY

Endothelial injury is the first step in atherosclerosis, where peripheral abnormalities correlate with coronary artery responses. The diffuse ECD in CTD suggests that vascular inflammation may initiate the accelerated CVS disease there. The new findings of similar ECD in primary SV predicts enhanced atherosclerosis here too. In Kawasaki syndrome, persistent late ECD correlates with abnormal coronary responses. In adult SV, initial data also suggests increased subclinical atherosclerosis. The role of endothelial function in the clinical outcome of SV deserves more attention. Research to pinpoint the mechanisms of ECD should lead to more specific therapies that may ameliorate the continuing late morbidity and mortality of SV.