Variants in the FFAR1 Gene Are Associated with Beta Cell Function

The FFAR1 receptor is expressed mainly in pancreatic beta cells and is activated by medium to long chain free fatty acids (FFAs), as well as by thiazolidinediones, resulting in elevated Ca(2+) concentrations and promotion of insulin secretion. These properties suggest that FFAR1 could be a mediator of lipotoxicity and a potential candidate gene for Type 2 diabetes (T2D). We therefore investigated whether variations at the FFAR1 locus are associated with T2D and beta cell function.We re-sequenced the FFAR1 region in 96 subjects (48 healthy and 48 T2D individuals) and found 13 single nucleotide polymorphisms (SNPs) 8 of which were not previously described. Two SNPs located in the upstream region of the FFAR1 gene (rs1978013 and rs1978014) were chosen and genotyped in 1929 patients with T2D and 1405 healthy control subjects. We observed an association of rs1978013 and rs1978014 with insulinogenic index in males (p = 0.024) and females (p = 0.032), respectively. After Bonferroni corrections, no association with T2D was found in the case-control material, however a haplotype consisting of the T-G alleles conferred protection against T2D (p = 0.0010).Variation in the FFAR1 gene may contribute to impaired beta cell function in T2D

Anti-platelet antibodies associated with the Canale–Smith syndrome bind to the same platelet glycoprotein complexes as those of idiopathic thrombocytopenic purpura patients

The Canale–Smith syndrome (CSS) is an inherited disease characterized by massive lymphadenopathy, hepatosplenomegaly and systemic autoimmunity to erythrocytes and platelets. Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disease in which approximately 60–80% of patients have anti-platelet antibodies directed against specific platelet glycoprotein complexes (GPCs) located on their membrane: GP IIb/IIIa, GPIb/IX, and GPIa/IIa. Almost all (95–100%) of the antibody-positive patients have antibodies directed against GPIIb/IIIa alone, or in combination with other glycoprotein targets. Our objective was to determine the specificities of the anti-platelet antibodies in CSS patients. The detection of anti-platelet antibodies was performed using a commercially available ELISA, the Pak-AUTO (GTI, Brookfield, WI), in which highly purified GPIIb/IIIa, GPIb/IX, and GPIa/IIa are immobilized on microtitre plates, incubated with serum or plasma, and subsequently developed with an antihuman polyclonal immunoglobulin. Of 14 CSS patients tested, 11 (79%) had anti-platelet antibodies in their serum directed toward at least one of the three major GPC, nine (82%) of which were against GPIIb/IIIa alone or in combination. Antibodies detected in the sera of ITP patients had similar specificities. No such antibodies were detected in samples from 25 consecutive normal controls. These results demonstrate that a genetically defined defect in lymphocyte apoptosis results in a humoral autoimmune response with anti-platelet specificities very similar to the common idiopathic form of autoimmune thrombocytopenia

Effects of deviating the Th2-response in murine mercury-induced autoimmunity towards a Th1-response

T-helper cells type 1 (Th1) and type 2 (Th2) play an important role in the pathogenesis of autoimmune diseases. In many Th1-dependent autoimmune models, treatment with recombinant interleukin-12 (rIL-12) accelerates the autoimmune response. Mercury-induced autoimmunity (HgIA) in mice is an H-2 regulated condition with antinucleolar antibodies targeting fibrillarin (ANoA), systemic immune-complex (IC) deposits and transient polyclonal B-cell activation (PBA). HgIA has many characteristics of a Th2 type of reaction, including a strong increase of IgE, but disease induction is critically dependent on the Th1 cytokine IFN-γ. The aim of this study was to investigate if a strong deviation of the immune response in HgIA towards Th1 would aggravate HgIA. Injections of both rIL-12 and anti-IL-4 monoclonal antibody (α-IL-4) reduced the HgCl(2)-(Hg-)induced concentration of the Th2-dependent serum IgE and IgG1, but increased the Th1-dependent serum IgG2a. The IgG-ANoA developed earlier and attained a higher titre after combined treatment, and the ANoA titre of the IgG1 isotype decreased while the ANoA titre of the Th1-associated IgG2a, IgG2b and IgG3-ANoA isotypes increased. Treatment with rIL-12 alone increased the Hg-induced IgG2a and IgG3 ANoA titres, the PBA, and the IC deposits in renal and splenic vessel walls, while treatment with α-IL-4 + Hg inhibited renal but not splenic vessel wall IC deposits. We conclude that manipulating the cytokine status, by altering the Th1/Th2 balance, will influence autoimmune disease manifestations. This might be an important way of modulating human autoimmune diseases