Background-Studies of human mast cells are constrained by the paucity of functional cell lines, the expense of maintaining mast cells in culture, and technical complexities.

No abstract

The etiology of chronic idiopathic urticaria (CIU) is attributed to autoantibodies directed against the alpha-chain of the high-affinity IgE receptor (FcepsilonRIalpha) or IgE on mast cells in 30-60% of patients. Approximately 30% of CIU patients have Hashimoto's thyroiditis (HT). We investigated the pathophysiologic relationship of anti-thyroid and anti-FcepsilonRIalpha antibodies. Nine individuals with both CIU and HT underwent autologous serum skin testing (ASST) and sera were assayed for thyroid autoantibodies, thyroid-stimulating hormone, and anti-FcepsilonRIalpha antibodies. Serum samples were studied for their ability to activate a human mast cell line (LUVA) as determined by cysteinyl leukotriene (CysLT) production. Experiments were performed to determine whether epitope cross-reactivity could explain the high incidence of HT found in CIU patients. A significant proportion of CIU patients had a positive ASST (nine of six) and anti-FcepsilonRIalpha antibodies (six of nine). Incubation of patient sera with FcepsilonRIalpha, but not thyroglobulin or thyroid peroxidase, resulted in the decreased ability to detect anti-FcepsilonRIalpha antibodies. Incubation with thyroid antigens did not inhibit CysLT production by mast cells. Epitopic cross-reactivity does not explain the increased prevalence of HT found in CIU patients. The frequent concurrence of HT and CIU likely reflects a genetic tendency toward autoimmune diseases.

Background-This study used serial volumetric intravascular ultrasound (IVUS) to evaluate the effect of preinterventional arterial remodeling on in-stent intimal hyperplasia (IH) after implantation of non-polymer-encapsulated paclitaxelcoated stents. Methods and Results-Patients were randomized to placebo or one of two doses of paclitaxel (low dose, 1.28 g/mm 2 ; high dose, 3.10 g/mm 2 ). Complete preinterventional, post-stent implantation, and follow-up IVUS were available in 18 low-dose and 21 high-dose patients. IH volumes were similar in low-dose and high-dose patients: 17.6Ϯ15.1 mm