The Study Of Correlation Between Polymorphism Of HLA-DRB Allele And Susceptivity Of Atopic Dermatitis

Atopic Dermatitise (AD) is a chronic inflammatory skin disease, and is often accompanied by families history. Serum IgE level is high and asthma and allergic rhinitis often exit. Pathogenesis is not well known. It is agreed that AD is a polygenic disease, heritage and environment leading to its development Foreign learner pay more and more attention to the susceptible gene(ig.l3q12,3q21,1q21) of AD. Howerer,they didn't reach an agreement. This might relate to the difference of AD diagnostic criterion,penetrance,,study strategy,ect. The distributive frequency varies in different areas and ethnics. So it is necessary to study the susceptible gene of AD in tianjin area.Human Leucocyte Antigen(HLA) plays a key role in immunoreactivity, especially HLA-II gene region, which regulate immunoreactivity by immunoreactive gene and immunoinhibit gene and attend the heritacy control of immunoreactivity. Thus we can know further the pathogenesis of AD by studying the relation between AD and HLA-II gene.In our study, HLA-DRB allele is tested,single-strand conformation polymorphism (SSCP) of DR3 is analysized and anti-h1 sIgE,anti-d1 sIgE,anti-d2 sIgE,anti-mx2 sIgE,anti-fx5E slgE is compared,to investigate the function of HLA-DRB in immunity regulation.First part:Polymerase Chain Reaction(PCR) is used to classify the HLA-DRB allel. The DR3 frequency of extrinic type of "pure" AD (BAD) group and complicated group is higher than cntrol(P<0.05),DR6 lower than control(P<0.05). There is no significance between instrinic type of "pure" AD (IAD) and control. In EAD,the relative rate(RR) of HLA-DR3,HLA-DR6 is 5.27, 0.10 respectively. In AD companing asthma and allergic rhinitis ,it is3.59, 0.00 respectively. It is indicated that people with HLA-DR3 are reliable to EAD,while people with HLA-DRg are not. HLA-DR3 is the susceptible gene of BAD, while HLA-DRj is the resistant gene of BAD and AD companing asthma and allergic rhinitis.Second part: DR3 multiphified products of 16 AD patients and 5 healthy controls with HLA-DR3 positive are tested by PCR-SSCP. There is only one patient whose SSCP band type is different from that of controls(PX).05). It is shown that indiduals carrying HLA-DR3 are reliable to AD, But there is no base difference between these people and the heality. It is not HLA-DR3 gene mutation that lead to the development of AD.Third part: Radioallergosorbent Test (RAST) is used to test the serum anti-h1 slgE ,anti-d, sIgE,anti-d2 sIgE,anti-mx2 sIgE,anti-fx5E sIgE in HLA-DR3 positive patients.Among 16 specimens,one anti-h, sIgE,three anti-d, slgE, twelve anti-d2 sIgE, one anti-mx2 sIgE,four anti-fx5E sIgE positive ,respetively. The comparsion between DR3 and anti-d2 sIgE has significance(P<0.05). It is indicated that entering the bodg,mite can be processed by antigen presenting cell(APC), then combine with HLA-DR3 specifically and form complex which can be identified by Th2 cell,stimulating the secretion of IL-4JL-13 and inducing the development of specific IgE. In this way, the immunoreactivity of body to mite is regulated and AD is induced.