Celiac disease: how complicated can it get?

In the small intestine of celiac disease patients, dietary wheat gluten and similar proteins in barley and rye trigger an inflammatory response. While strict adherence to a gluten-free diet induces full recovery in most patients, a small percentage of patients fail to recover. In a subset of these refractory celiac disease patients, an (aberrant) oligoclonal intraepithelial lymphocyte population develops into overt lymphoma. Celiac disease is strongly associated with HLA-DQ2 and/or HLA-DQ8, as both genotypes predispose for disease development. This association can be explained by the fact that gluten peptides can be presented in HLA-DQ2 and HLA-DQ8 molecules on antigen presenting cells. Gluten-specific CD4+ T cells in the lamina propria respond to these peptides, and this likely enhances cytotoxicity of intraepithelial lymphocytes against the intestinal epithelium. We propose a threshold model for the development of celiac disease, in which the efficiency of gluten presentation to CD4+ T cells determines the likelihood of developing celiac disease and its complications. Key factors that influence the efficiency of gluten presentation include: (1) the level of gluten intake, (2) the enzyme tissue transglutaminase 2 which modifies gluten into high affinity binding peptides for HLA-DQ2 and HLA-DQ8, (3) the HLA-DQ type, as HLA-DQ2 binds a wider range of gluten peptides than HLA-DQ8, (4) the gene dose of HLA-DQ2 and HLA-DQ8, and finally,(5) additional genetic polymorphisms that may influence T cell reactivity. This threshold model might also help to understand the development of refractory celiac disease and lymphoma

EORTC study non-hodgkin's lymphoma: Phase III study comparing CHVmP-VB vs ProMACE-MOPP in patients with stage II-III-IV intermediate and high grade lymphoma

info:eu-repo/semantics/publishe

Involved-field radiotherapy for advanced Hodgkin's lymphoma

info:eu-repo/semantics/publishe

Immunogenetics of Celiac Disease

Celiac disease (CD) is a model for common complex disorders with a high degree of heritability. The human leukocyte antigen (HLA) DQ genotype, specifically HLA-DQ2 and HLA-DQ8, is the strongest genetic risk factor. Genome-wide association studies (GWAS) have identified 57 single nucleotide polymorphisms (SNPs) located in the associated 39 non-HLA regions with mainly immunological functions. Together with HLA, these regions explain approximately 54 % of the disease’s heritability. Molecular functional analyses are necessary to delineate the true causal genetic variants and the pathways involved. Since CD shares many of its genetic susceptibility regions and implicated pathways with other immune-related diseases, a combined analysis may discover more common genetic variants with smaller effect sizes. HLA-DQ genotyping can already be used to exclude a diagnosis of CD, for example, as a test in the screening of individuals from high-risk groups, such as patients with type 1 diabetes or autoimmune thyroiditis, and first-degree relatives of CD patients. Discovering more genetic susceptibility variants and the pathways involved may ultimately contribute to risk stratification for follow-up and treatment, and lead to new therapeutic targets