susceptibility cassette

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susceptibility cassette

a common sequence of amino acids in residues 70-74 in the HLA-DRB1 chains, found in alleles associated with rheumatoid arthritis. It is one of two variations: glutamine[Q]-lysine[K]-arginine[R]-alanine[A]-alanine[A] or QRRAA. These susceptibility cassettes are found in many different DRB1 alleles. The α and β chains that form these antigen-presenting molecules have a configuration not unlike a trough or rain gutter; antigens are bound by sequences of amino acids in a pocket along the bottom and sides of the trough or cavity, and this complex forms a heterotrimer with the T-cell receptor on CD4+ cells.

sus·cep·ti·bil·i·ty cas·sette

(sŭ-sep'ti-bil'i-tē kă-set')
A common sequence of amino acids in residues 70-74 in the HLA-DRB1 chains, found in alleles associated with rheumatoid arthritis. It is one of two variations: glutamine[Q]-lysine[K]-arginine[R]-alanine[A]-alanine[A] or QRRAA; found in many different DRB1 alleles. The alpha and beta chains that form these antigen-presenting molecules have a configuration not unlike a trough or rain gutter; antigens are bound by sequences of amino acids in a pocket along the bottom and sides of the trough or cavity, and this complex forms a heterotrimer with the T-cell receptor on CD4+ cells.
Synonym(s): rheumatoid pocket, shared epitope.
References in periodicals archive ?
This is in contrast to findings by other investigators who have recently reported that the presence of anti-CCP antibodies together with shared epitope (SE) gene carriage is associated with a very high relative risk for future development of RA (4).
Diagnostic performance and predictive value of rheumatoid factor, anti-citrullinated peptide antibodies, and the HLA shared epitope for the diagnosis of rheumatoid arthritis.
From the clinicians point of view, it is beneficial to outline briefly the current clinical practice to better understand the diagnostic performance and predictive value of RF, ACPAs, and HLA class 11 shared epitope for the diagnosis of RA, as discussed by Hoffman et al.
More recently, a nationwide case-control study conducted in Denmark between 2002 and 2004 found that subjects who were shared epitope carriers and smoked, drank more than five cups of coffee each day, or used oral contraceptives were at high risk for anti-CCP-positive RA.
The presence of the HLA-DRB1 gene--which is also known as the shared epitope and, until recently, was considered the most important genetic factor in RA--conferred only a twofold increased relative risk of future RA in the Swedish population, the physician observed at the congress, which was sponsored by the European League Against Rheumatism (EULAR).
The rate of radiographic progression of articular cartilage destruction, as assessed by the van der Heijde-modified Sharp score, was significantly greater in PTPN22-positive than in PTPN22-negative RA patients, and occurred independently of the shared epitope, she reported.
The HLA-DRB1 shared epitope in Caucasians with rheumatoid arthritis: a lesson learned from tic-tac-toe.
Shared epitope alleles remain a risk factor for anti-citrullinated proteins antibody (ACPA) positive rheumatoid arthritis in three asian ethnic groups.
The HLA-DRB1 shared epitope is not associated with antibodies gainst cyclic citrullinated peptide in Chinese patients with rheumatoid arthritis.
All of these HLA-DRB1 alleles increasing risk of RA share common QKRAA, QRRAA and RRRAA amino acid sequences termed the shared epitope (SE) at positions 70-74.
Experimental studies have shown that conversion of arginine to citrulline at the peptide side-chain position significantly increases the affinity of a peptide for binding to major histocompatability complex and can lead to activation of CD4 positive T cells in transgenic mice having one of these shared epitope alleles.
However, presence of shared epitope HLA-DRB1 alleles, which was examined in patient group, was not examined in healthy controls due to its high cost.
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