title: Association between interleukin-6 polymorphism and age-at-onset of type 1 diabetes. Epistatic influences of the tumor necrosis factor-alpha and interleukin-1beta polymorphisms.
abstract: Multiple immune mediators have been mentioned as playing a role in the pathomechanism of type1 DM. Interleukin (IL)-1beta, and tumor necrosis factor (TNF)-alpha play a central role in the autoimmune destruction of pancreatic beta-cells, whereas IL-6 inhibits TNF-alpha secretion, and may have some protecting effects. In our study, we aimed to investigate the association between these three cytokines' single nucleotide polymorphisms (IL-6 gene G(-174)C, TNF-alpha gene G(-308)A and IL-1beta gene C(3954)T polymorphisms) and age-at-onset of type 1 diabetes mellitus (T1DM) in 165 diabetic children (median age: 17 years). Polymorphisms were determined using the PCR-RFLP method. We found that the age-at-onset of T1DM was significantly different in patients with a different IL-6 genotype (median age-at-onset of T1DM was: 8, 6 and 4.5 years in children with the (-174)GG, GC and CC genotypes, respectively; p < 0.01). Adjusted for TNF-alpha and IL-1beta polymorphisms, patients with a IL-6 (-174)CC genotype have a 3.0-fold (95% CI: 1.2-7.1) increased risk of developing diabetes before the age of 6 years than (-174)G allele carrier patients. However, we found this association to be present only in patients who carried the TNF-alpha (-308)A or IL-1beta (3954)T allele, i.e. in patients with high TNF-alpha and high IL-1beta producer genotypes. We suppose that in the case of high TNF-alpha and IL-1beta producer genotypes, elevated proinflammatory cytokine levels result in a higher production of IL-6 in (-174)G allele carrier patients. This elevated IL-6 level may have a protective effect against the development of T1DM and may delay the destruction of pancreatic beta-cells.
authors.affiliation: Department of Anesthesiology and Intensive Therapy, Semmelweis University, Budapest, Hungary. hecsito@axelero.hu
authors.forename: Csaba
authors.initials: C
authors.lastname: Hermann
authors.forename: Dóra
authors.initials: D
authors.lastname: Krikovszky
authors.forename: George
authors.initials: G
authors.lastname: Füst
authors.forename: Margit
authors.initials: M
authors.lastname: Kovács
authors.forename: Anna
authors.initials: A
authors.lastname: Körner
authors.forename: András
authors.initials: A
authors.lastname: Szabó
authors.forename: Adám
authors.initials: A
authors.lastname: Vannay
authors.forename: László
authors.initials: L
authors.lastname: Madácsy
mesh_terms: D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004843:Epistasis, Genetic; D005260:Female; D006580:Genetic Carrier Screening; D005838:Genotype; D006801:Humans; D050417:Insulin-Secreting Cells / Q000378:metabolism / Q000473:pathology; D053583:Interleukin-1beta / Q000235:genetics*; D015850:Interleukin-6 / Q000235:genetics*; D008297:Male; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012044:Regression Analysis; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D053583:Interleukin-1beta; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha