Persistent Immune Tolerance to Nickel and Chromium by Oral Administration Prior to Cutaneous Sensitization

Oral administration of allergens, foreign proteins, or cell- bound antigens may induce systemic suppression of subsequent humoral and cell-mediated immune responses (“oral tolerance”) The induction of specific immune tolerance provides a potential strategy for treatment of T-cell dependent immune diseases. Therefore, in depth studies into reconditions for optimal and persistent tolerance induction are mandatory. Here we report on such studies in a guinea pig model using the non-cross-reactive contact allergens nickel and chromium. Feeding per os of nickel sulfate or potassium. dichromate did not trigger systemic TDTH-effector functions. Instead, short feeding periods led to a close-dependent, and metal-specific, suppression of subsequently induced allergic contact hypersensitivity. Administration of the allergens onto the oral mucosa was most effective in the induction of immune tolerance. When first sensitizing attempts were delayed until 1 year after feeding, the degree of unresponsiveness was reduced. In contrast, with cutaneous contacts starting Shortly after the feeding period, tolerance was fully stable and undiminished for at least 2 years. Thus, in orally treated guinea pigs cutaneous contacts provide boosting tolerogenic signals, supporting the view that oral tolerance does not result from clonal deletion but from active antigen-specific immunosuppression. Indeed, unresponsiveness to cutaneous immunization could be transferred by lymphoid cells from fed guinea pigs in a metal-specific way

Intestinal barrier gene variants may not explain the increased levels of antigliadin antibodies, suggesting other mechanisms than altered permeability

Various genes may influence intestinal barrier function, including MAGI2, MY09B, and PARD3, which are associated with celiac disease. Because direct measurement of intestinal permeability is difficult, antibodies against gliadin (AGA) and Baker's yeast (anti-Saccharomyces cerevisiae antibodies [ASCA]) can be used as an indirect test. The objective of this study was to investigate whether intestinal permeability, represented by AGA, was correlated with MAGI2, MY09B, and PARD3. Analyses were performed in patients with Down syndrome, a population with suspected increased intestinal permeability. Correlations between AGA and ASCA were investigated. Patients with Down syndrome (n = 126) were genotyped for six single-nucleotide polymorphisms in MAGI2 (rs1496770, rs6962966, rs9640699), MY09B (rs1457092, rs2305764), and PARD3 (rs10763976). An allele dosage association of these risk genes and AGA levels was performed. The correlation between AGA and ASCA was studied. A strong correlation was found between AGA and ASCA (p <0.01). The patient group with one or more risk genotypes had lower mean AGA levels (trend test p = 0.007) and consisted of a larger number of patients with normal AGA levels (p = 9.3 x 10(-5)). Celiac-associated risk genotypes are associated with lower AGA values instead of elevated ones. Thus, other immunologic phenomena play a role in the increased prevalence of elevated AGA in patients with Down syndrome, possibly involving altered induction and/or maintenance of tolerance. (C) 2010 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved

A multiplex assay to rapidly exclude HLA-DQ2.5 and HLA-DQ8 expression in patients at risk for celiac disease

<p>Background: Celiac disease (CD) is an inflammatory disorder of the small intestine induced by gluten ingestion. CD has a strong genetic association with human leukocyte antigen (HLA)-DQ2.5 and HLA-DQ8. The absence of HLA-DQ2.5 and HLA-DQ8 has a strong negative predictive value for CD. Genetic screening of HLA-DQ2.5 and HLA-DQ8 in patients at risk is of great value.</p><p>Methods: We designed, developed, and validated a multiplex assay based on multiplex ligation-dependent probe amplification (MLPA) technology, allowing the simultaneous detection of DQA1*05-DQB1*02, encoding HLA-DQ2.5, and DQA1*03-DQB1*03:02, encoding HLA-DQ8. The amplified products were separated and identified using capillary electrophoresis.</p><p>Results: When compared with a polymerase chain reaction followed by single-strand conformation polymorphism/heteroduplex analysis, one discrepancy was found. Sequencing analysis showed that the developed MLPA assay result was correct. Furthermore, we demonstrated that the MLPA method is able to distinguish between the heterozygote and homozygote expression of HLA-DQ2.5 or HLA-DQ8.</p><p>Conclusions: This study shows that it is possible to rapidly and accurately screen for the absence of HLA-DQ2.5 and HLA-DQ8 using MLPA, excluding patients at risk for CD for further serological or histological follow-up. In addition, MLPA might be an accurate tool to screen for other specific HLA types in the context of disease association in a diagnostic laboratory setting.</p>

Increased progression of carotid intima media thickness in thyroid peroxidase antibodies-positive rheumatoid arthritis patients

Objective: Autoimmune diseases such as rheumatoid arthritis (RA) and hypothyroidism tend to cluster, and this coexistence amplifies the elevated cardiovascular risk in RA. Whether thyroid peroxidase antibodies (TPOabs) are associated with increased cardiovascular disease (CVD) risk has not been studied extensively. Therefore, this study determined firstly the prevalence of TPOabs in RA and secondly whether TPOabs were associated with CVD. Moreover, this study explored whether TPOabs were related to RA characteristics. Design and methods: Data from the CARRÉ Study, an ongoing study investigating CVDs and its risk factors in RA (n=322), was used to ascertain the prevalence of TPOabs in RA patients. In addition, cardiovascular and RA disease characteristics were compared between TPOabs-positive and -negative patients at baseline and at a second visit after 3 years. Results: TPOabs were present in 47/322 (15%) RA patients and TSH levels were higher in TPOabspositive patients (1.40 mU/l) compared with TPOabs-negative patients (1.26 mU/l, P=0.048). At baseline and after 3 years no association was observed between TPOabs and (risk factors for) CVD. Regression analyses revealed a significantly larger progression of carotid intima media thickness (cIMT; β=0.13 mm) in TPOabs-positive compared with TPOabs-negative patients independent of risk factors for cIMT progression. RA disease activity scores (DAS28) were higher in TPOabs-positive compared with TPOabs-negative patients (4.4 vs 3.8 P=0.018). Conclusions: TPOabs were associated with increased cIMT progression. Moreover, an association between TPOabs and DAS28 was observed. Hence, TPOabs seems to have a role in the amplified cardiovascular risk in RA patients