Serum IL-18 levels in patients with type 1 diabetes: Relations to metabolic control and microvascular complications

The study was designed to examine serum IL-18 level and its relation to metabolic control parameters and microvascular complications in type 1 diabetes mellitus (DM). Sixty two patients with type 1 DM and 30 healthy individuals were enrolled in the study. Serum IL-18 levels of patients with type 1 DM were significantly increased compared to controls (293.4 ± 133.4 vs 211.2 ± 63.9 pg/ml, P = 0.003). Patients with poor glycemic control had higher levels of IL-18 than patients with well glycemic control (329.9 ± 141.0 vs 226.3 ± 89.6 pg/ml, P = 0.02). There was no significant difference between the serum IL-18 levels of patients with microvascular complications and those of patients without microvascular complications (307.6 ± 127.6 vs 293.2 ± 145.6 pg/ml, P > 0.05). IL-18 correlated positively with HbA1c (r = 0.32, P = 0.01) and postprandial blood glucose (PPBG) (r = 0.26, P = 0.02); and negatively with HDL-cholesterol (HDL-C) (r = −0.38, P = 0.007). By linear regression analysis, PPBG was determined as the most explanatory parameter for the alterations in serum IL-18 levels (P = 0.02). High levels of IL-18 in patients with type 1 DM is related to short and long term glycemic control and HDL-C levels but not to microvascular complications.