RT Journal Article SR Electronic T1 Interleukin-6 gene polymorphism and insulin sensitivity. JF Diabetes JO Diabetes FD American Diabetes Association SP 517 OP 520 DO 10.2337/diabetes.49.3.517 VO 49 IS 3 A1 Fernández-Real, J M A1 Broch, M A1 Vendrell, J A1 Gutiérrez, C A1 Casamitjana, R A1 Pugeat, M A1 Richart, C A1 Ricart, W YR 2000 UL http://diabetes.diabetesjournals.org/content/49/3/517.abstract AB Type 2 diabetes and the insulin resistance syndrome have been hypothesized to constitute manifestations of an ongoing acute-phase response. We aimed to study an interleukin-6 (IL-6) gene polymorphism in relation to insulin sensitivity (IL-6 is the main cytokine involved in an acute-phase response). Subjects homozygous for the C allele at position -174 of the IL-6 gene (SfaNI genotype), associated to lower plasma IL-6 levels, showed significantly lower integrated area under the curve of serum glucose concentrations (AUCglucose) after an oral glucose tolerance test, lower blood glycosylated hemoglobin, lower fasting insulin levels, lower total and differential white blood cell count (a putative marker of peripheral IL-6 action), and an increased insulin sensitivity index than carriers of the G allele, despite similar age and body composition. A gene dosage effect was especially remarkable for AUCglucose (6.4 vs. 9.3 vs. 9.7 mmol/l in C/C, C/G, and G/G individuals, respectively). The serum concentration of fully glycosylated cortisol binding globulin (another marker of IL-6 action), suggested by concanavalin A adsorption, was lower in C/C subjects than in G/G individuals (32.6+/-2.9 vs. 37.6+/-4.6 mg/l, P = 0.03). In summary, a polymorphism of the IL-6 gene influences the relationship among insulin sensitivity, postload glucose levels, and peripheral white blood cell count.