The Expression Of HLA-DRB Allel And T-cell Receptor V Beta-chains In Atopic Dermatitis

Objective:Atopic Dermatitise (AD) is a chronic inflammatory skin disease, and itspathogenesis is complicated. The aim of the study was to characterize the expressionof HLA-DRB allel and T-cell receptor V beta-chains in atopic dermatitis, and findmolecular immunology mechanism of AD.Methods:1:Skin prick test was used to search the frequent antigens of 40 patients withatopic dermatitis.2: Polymerase Chain Reaction (PCR) was used to classify the HLA-DRB allel.The relative rate(RR) of HLA-DRB which presented positive were calculated to lookfor the susceptible gene and resistant gene of AD.3: All the subjects were tested the serum anti-h₁ sIgE, anti-d₁ sIgE, anti-d₂ sIgE,anti-rex₂ sIgE, anti-fx5E sIgE by using Radioallergosorbent Test (RAST). Thenthe relationship between HLA-DRB and special antigen was caculated.4: The TCR repertoires of 6 healthy individual and 8 AD patients who had positiveexpression of special HLA-DR and with special allergy were detected. By using flowcytometry, the expansion of 24 Vβelements was analyzed in vivo and in vitro afterstimulated by special allergen.Results:1,The positive sort order of antigens is: dust mite (45%), dust (37.5%), combined inhaled antigens (30%) and spring pollen antigenâ…¡(22.5%).2,HLA-DRB genes expression: The HLA-DR₃ frequency of AD group is higherthan control(p＜0.05), HLA-DR₆ lower than control(p＜0.05). In AD, the relativerate(RR) of HLA-DR₃ is 6.33＞4, HLA-DR₆ is 0.31＜1. It is indicated that peoplewith HLA-DR₃ are reliable to AD,while people with HLA-DR₆ are not.3,Among 16 specimens, one anti-h₁ sIgE, three anti-d₁ sIgE, twelve anti-d₂ sIgE,one anti-mx₂ sIgE, four anti-fx5E sIgE positive, respetively. The comparsionbetween DR₃ and anti-d₂ sIgE has significance(p＜0.05).4,In comparison with in vivo and in vitro stimulated by dust mite antigen or PHA,none of TCRVβexpansion has statistically different in either AD patients or healthyindividual. But in comparison with freshly isolated PBMCs of AD individuals,TCRVβ18⁺ T cell showed a higher frequency after stimulated by dust mite antigen(2.19±2.04) than in vivo (1.26±1.49). Especially, one of the patients TCRVβ18⁺showed a significantly higher frequency from 0.56% to 3.99%. And there is noexpansion of Vβ18⁺ was observed after mitogen stimulation with PHA (1.53±2.05),indicating allergen specificity of the response.Conclusion:1,Dust mite is the most popular antigen for atopic dermatitis patients, and it take agreat role in AD.2,The HLA-DR₃ frequency of AD group is higher than control(p＜0.05), whileHLA-DR₆ lower than control(p＜0.05). HLA-DR₃ is the susceptible gene of AD,while HLA-DR6 is the resistant gene of AD.3,A statistically significant relationship between HLA-DR₃ and serum levels ofspecial IgE by house dust mites (p＜0.05) was determined. It is indicated that enteringthe body,mite can be processed by antigen presenting cell (APC), then combinedwith HLA-DR₃ specifically to form the complex which stimulate the differentiation of T lymphocyte and result immunoregulatory disorders.4,Our results suggest it is possible for TCRVβ18⁺ T cell to play a role in dust miteallergy of AD.