Citations

Giant cell arteritis (GCA) is a granulomatous and occlusive vasculitis that causes blindness, stroke, and aortic aneurysm. CD4+ T cells are selectively activated in the adventitia of affected arteries. In human GCA artery–severe combined immunodeficiency (SCID) mouse chimeras, depletion of CD83+ dendritic cells (DCs) abrogated vasculitis, suggesting that DCs are critical antigen-presenting cells in GCA. Healthy medium-size arteries possessed an indigenous population of DCs at the adventitia–media border. Adoptive T cell transfer into temporal artery–SCID mouse chimeras demonstrated that DCs in healthy arteries were functionally immature, but gained T cell stimulatory capacity after injection of lipopolysaccharide. In patients with polymyalgia rheumatica (PMR), a subclinical variant of GCA, adventitial DCs were mature and produced the chemokines CCL19 and CCL21, but vasculitic infiltrates were lacking. Human histocompatibility leukocyte antigen class II–matched healthy arteries, PMR arteries, and GCA arteries were coimplanted into SCID mice. Immature DCs in healthy arteries failed to stimulate T cells, but DCs in PMR arteries could attract, retain, and activate T cells that originated from the GCA lesions. We propose that in situ maturation of DCs in the adventitia is an early event in the pathogenesis of GCA. Activation of adventitial DCs initiates and maintains T cell responses in the artery and breaks tissue tolerance in the perivascular space.

Background— Diabetes portends an adverse prognosis in patients undergoing percutaneous coronary intervention (PCI). Whether improvements in current clinical practice (stents, IIb/IIIa antagonists) have resulted in substantial improvement of these outcomes remains an issue. The aim of this study was to determine the influence of diabetes on 9-month outcomes of patients undergoing PCI in the current era. Methods and Results— The 11 482 patients enrolled in the Prevention of REStenosis with Tranilast and its Outcomes (PRESTO) Trial were stratified according to the presence (n=2694) or absence (n=8798) of diabetes. Diabetic patients were older; were more likely to be female; had a higher proportion of congestive failure, hypertension, prior CABG, and unstable angina; and had higher body mass index and lower ejection fraction than nondiabetic patients ( P <0.01 for all comparisons). The degree of multivessel disease was similar between the two groups. American College of Cardiology/American Heart Association type C lesions were more common in diabetic patients (17% versus 15%, P <0.01). Angiographic and procedural success rates and in-hospital events were similar between the two groups. The primary end point of death, myocardial infarction, or target vessel revascularization (TVR) was analyzed as time-to-first event within 9 months of the index PCI. After adjusting for certain baseline characteristics, diabetes was independently associated with death at 9 months (relative risk [RR], 1.87; 95% CI, 1.31 to 2.68, P <0.01) and with an increased likelihood of TVR (RR, 1.27; 95% CI, 1.14 to 1.42, P <0.01), as well as the composite end point of death/myocardial infarction/TVR (RR, 1.26; 95% CI, 1.13 to 1.40, P <0.01). Conclusions— Despite advances in interventional techniques, diabetes remains a significant independent predictor of adverse events in the intermediate term after PCI.

Ischemic damage to the subcortical white matter of the brain, referred to as leukoaraiosis, is a frequent complication of hypertension-related microvascular disease and contributes to the risk of stroke and vascular dementia. A large genetic contribution to this late-life form of target organ damage was suggested by a study of elderly male twins. As part of the Genetic Epidemiology Network of Arteriopathy (GENOA), 483 non-Hispanic white subjects were recruited to undergo MRI for determination of the brain volume of leukoaraiosis (291 women and 192 men from 210 sibships providing 434 sibling pairs; mean age±SD=65.2±7.3 years). The GENOA–Rochester sibships contain 2 or more siblings with essential hypertension diagnosed before age 60. The frequency distribution of the volume of leukoaraiosis was positively skewed, with a median value of 6.61 cm 3 (interquartile range: 4.77 to 9 0.83 cm 3 ). Variance component models were used to estimate the heritability (ie, the proportion of phenotypic variation caused by additive genetic factors). After logarithm transformation of the volume of leukoaraiosis, the estimated heritability (±SE) was 0.802±0.102 ( P <0.0001). Adjustments for sex, age, systolic blood pressure, and brain volume reduced the heritability estimate to 0.671±0.110 ( P <0.0001). This evidence of strong genetic influence on the susceptibility to leukoaraiosis justifies efforts to localize the responsible genes and characterize the predisposing genetic polymorphisms.

SUMMARYFamilial and twin studies in Caucasians have established that the MHC class II allele HLA-DRB1*0301 (DR3) is a strong susceptibility gene in Graves’ hyperthyroid disease (GD). To determine if a DR3 transgene could help establish an animal model for GD, we expressed DR3 molecules in class II-knockout NOD mice (H2Ag7–). DR3+g7– mice were given cardiotoxin prior to immunization on weeks 0, 3 and 6 with plasmid DNA encoding human thyrotropin receptor (TSHR). Two groups of mice were also coimmunized with plasmid DNA for IL-4 or GM-CSF. Serial bleeds on weeks 8, 11 and 14 showed that approximately 20% of mice produced thyroid-stimulating antibodies (Abs), and approximately 25% had elevated T4 levels. In particular, a subset displayed both signs of hyperthyroidism, resulting in approximately 30% with some aspect of GD syndrome. Additional mice had thyroid-stimulating blocking Abs and/or TSH-binding inhibitory immunoglobulins, while most mice showed strong labelling of TSHR+ cells by flow cytometry. Interestingly, lymphocytic infiltration with thyroid damage and Abs to mouse thyroglobulin were also noted. Vector controls were uniformly negative. Thus, DR3 transgenic mice can serve as a model for GD, similar to our earlier reports that this allele is permissive for the Hashimoto's thyroiditis model induced with human thyroglobulin.

Pulmonary hemangiomas are exceptionally rare in childhood and more so in infancy. They may involve the airways or the parenchyma, and may be localized or multifocal. We present two cases of pulmonary capillary hemangiomas. The first case is a localized form of capillary hemangioma that was resected from an 8-week-old infant with signs of respiratory distress. A computed tomography scan showed a cystic mass initially thought to be an intrapulmonary bronchogenic cyst. A segmental resection was performed and examination revealed a localized capillary hemangioma without cystic or cavernous features. The second case is an example of a multifocal capillary hemangioma from a 9-year-old child who presented clinically with clubbing of fingers and toes and radiologically had multiple discrete nodules localized to the right lung. The clinical and pathological features of the cases are discussed together with a review of the literature. The distinction from other vascular neoplasms of childhood is briefly described. Although rare, pulmonary hemangiomas should be entertained in the diagnosis of both solid and cystic intrapulmonary lesions of childhood and infancy.

In rheumatoid arthritis, peripheral blood T cells have age-inappropriate telomeric erosion. We examined whether HLA-DRB1 * 04 alleles, the major susceptibility genes for this disease, confer risk for T cell senescence. In healthy individuals, HLA-DRB1 * 04 alleles were associated with excessive loss of telomeres in CD4 + T cells. Accelerated telomeric erosion occurred during the first two decades of life and was followed by reduced homeostatic T cell proliferation during adulthood. Premature telomeric loss also affected granulocytes, suggesting that the hematopoietic stem cell is the primary target. Telomeric repair mechanisms were intact in HLA-DRB1 * 04 + donors. We propose that HLA-DRB1 * 04 alleles or genes in linkage disequilibrium regulate stem cell replication and contribute to the accumulation of senescent and autoreactive T cells in rheumatoid arthritis.