We attempted to investigate the correlation between the severity of atopic dermatitis (AD) in children and the indoor level of house dust mite (HDM) allergens. Ninety-five patients (31.1 +/- 19.5 months of age) with AD were enrolled in this study, and serum specific IgE against Dermatophagoides pteronyssinus and D. farinae was measured. The severity of AD was assessed using the visual analogue scale on the same day of house dust collection. Living rooms and mattresses where the child usually slept were vacuumed for 2 minutes and concentrations of Der f 1 were measured by enzyme-linked immunosorbent assay. The skin symptoms were more severe in patients with Der f 1 concentrations in living room > 2 microg/g dust than < or = 2 microg/g dust (P = 0.018). This difference was noted in AD patients without sensitization to HDM (P = 0.004), but not in patients with sensitization. There was no difference in symptom severity according to Der f 1 concentrations in mattresses (P = 0.062). The severity of skin symptoms is associated with indoor concentrations of HDM in children with AD, and it is likely to act as nonspecific irritants as well as allergens in AD skin lesions.
Adolescent ; Animals ; Antigens, Dermatophagoides/*analysis ; Beds/parasitology ; Child ; Child, Preschool ; Dermatitis, Atopic/*diagnosis/pathology ; Dermatophagoides farinae/immunology ; Dermatophagoides pteronyssinus/immunology ; *Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Immunoglobulin E/blood ; Infant ; Male ; Severity of Illness Index

PURPOSE: Cutaneous lymphocyte-associated antigen (CLA)-expressing CD8+T cells have been known to play an important role in the pathogenesis of atopic dermatitis (AD). However, the mechanisms underlying the loss of self-tolerance remain unclear. Regulatory T cells (Tregs) play a key role in the development of homeostasis in the immune system. We, therefore, hypothesized that a reduced ability of Tregs to inhibit autologous CD8+CLA+T cells might be underlying mechanism in AD. MATERIALS AND METHODS: CD8+CLA+T cells and Tregs were obtained from the peripheral blood of AD patients and control volunteers. The frequencies of CD8+CLA+T cells were evaluated. The proliferative responses of CD8+CLA+T cells were assessed by flow cytometry, and the levels of transforming growth factor-beta1 (TGF-beta1) and interleukin-10 (IL-10) in culture supernatants were detected by enzyme-linked immunosorbent assay. RESULTS: Our results revealed higher frequency and increased expression of perforin and granzyme-B in peripheral CD8+CLA+T cells in AD, and lower inhibitory ability of Tregs on proliferation of CD8+CLA+T cells in AD. Meanwhile, the levels of TGF-beta1 produced by Tregs were significantly lower in AD, and anti-TGF-beta1 abolished such suppression. CONCLUSION: The attenuated inhibitory ability of Tregs on hyper-activated autologous CD8+CLA+T cells, mediated by TGF-beta1, plays an important role in the pathogenesis of AD.
Adult ; Aged ; CD8-Positive T-Lymphocytes/drug effects/*immunology ; Case-Control Studies ; Cell Proliferation ; Cell Separation ; Dermatitis, Atopic/*immunology/pathology ; Female ; Granzymes/metabolism ; Humans ; Interleukin-10/metabolism ; Lymphocyte Count ; Male ; Perforin/metabolism ; Skin/*immunology/pathology ; T-Lymphocytes, Cytotoxic/drug effects/immunology ; T-Lymphocytes, Regulatory/drug effects/*immunology ; Transforming Growth Factor beta1/pharmacology