Thymus is Enlarged in Children with Current Atopic Dermatitis. A Cross-sectional Study

Abstract

Atopic dermatitis is a common skin disorder of unknown aetiology with peak incidence in early childhood. The disease is associated with peripheral T-cell accumulation in the skin. The thymus is a key organ of the cellular immune response early in life. We hypothesized that atopic dermatitis is associated with an unbalanced establishment of the peripheral T-lymphocyte system. This cross-sectional study was performed to compare thymus sizes in patients with atopic dermatitis and healthy controls. Thirty-seven children with current atopic dermatitis were enrolled and compared with 29 healthy controls. An interview and medical examination were performed by one doctor, an ultrasound scan was performed within 3 days of the examination, and the thymus index, a marker of thymus size, was measured. The thymus index was on average 32% higher (95% CI 3%-67%) in children with active atopic dermatitis compared with healthy controls. It declined with age in both children with atopic dermatitis and healthy controls, but the reduction in size was only significant for healthy controls. We demonstrate increased size of thymus among children with active atopic dermatitis compared with healthy controls. The larger size of thymus is compatible with increased thymic activity and emission of T lymphocytes.

Serum mucosa-associated epithelial chemokine in atopic dermatitis : A specific marker for severity

“…[4] These cells can be detected in a significant proportion in the peripheral blood of children with AD. [1] This may suggest a faulty maturation of the T-lymphocyte system as a basic pathophysiological change in AD, leading to skin inflammation with CD4 + CD8 + T lymphocytes resembling immature T cells. [21] This is likely to lead to the skewing of many immune reactions in those patients.…”

“…It was hypothesized that AD is associated with an unbalanced establishment of the peripheral T-lymphocyte system. Cutaneous lymphocyte-associated antigen (CLA)[1] is a cell surface glycoprotein that has been postulated to play an important role in T-cell migration and homing to the skin. It has been proposed that interaction between T cells and epidermal keratinocytes plays a central role in the pathogenesis of AD.…”

T-cell Receptor Excision Circles (TREC) in CD4+ and CD8+ T-cell Subpopulations in Atopic Dermatitis and Psoriasis Show Major Differences in the Emission of Recent Thymic Emigrants

“…E-mail: ktp56@hotmail.com Atopic dermatitis (AD) is a disorder with accumulation of activated T cells in the skin and, in some patients, increased IgE production leading to type I allergies to environmental allergens (1). We have demonstrated a significant increase in thymic volume in infants and children with active AD, an increased number of lymphocytes in the skin, an increased telomerase activity and shortened telomere length in T cells both in blood and skin, and an increased number of double-positive CD4+CD8+ T cells in peripheral blood (2)(3)(4)(5). These results suggest that patients with AD have a dysregulation of thymic T-cell selection and emission ( 6) and increased T-cell turn-over in the peripheral immune system.…”

Significant Differences in Thymic Index of Thalassemia Major Patients

“…In one study it was shown that thymus size declined with age in both children with atopic dermatitis and healthy controls. However, the size of the thymus among children with active atopic dermatitis was higher compared to healthy controls [ 3 ]. Having a smaller thymus may be an advantage for TM patients, who are prone to alloimmunization related to transfusion.…”