The relation of serum IL-18, TNF-alpha and IL-6 levels to type 1 diabetes mellitus and microvascular complications

Recently, there is some evidence that subclinical inflammation has a role in both type1 diabetes and pathogenesis of its complications. In our study, we investigated IL-18, TNF-alpha and IL-6 levels in patients with type 1 diabetes and healthy controls. We alsoinvestigated the relation of these cytokines to duration of diabetes, metabolic parametersincluding glycemic control and lipid profile as well as microvascular complications. Seum IL-18, TNF-alpha, and IL-6 levels were measured in 92 subjects (62 patients with type 1 diabetesand 30 healthy controls). HbA1c, fasting glucose, postprandial glucose, lipids, urinaryalbumin excretion were measured and fundus examinations were performed in diabeticpatients. IL-18 levels were increased in diabetic patients compared to controls. TNF-alpha andIL-6 levels of diabetic patients were similar to those of controls. IL-18, TNF-alpha ve IL-6levels were not significantly different between the patients with microvascular complicationsand the patients without microvascular complications. Patients with poor glycemic controlhad increased IL-18 levels compared to those with good glycemic control. In diabetic patients,IL-18 levels correlated with HbA1c, postprandial glucose and HDL-cholesterol and TNF-alpha levels correlated with total-cholesterol and urinary albumin excretion and IL-6 levelscorrelated with HDL-cholesterol and triglycerides. In conclusion, IL-18, one of the markers ofsubclinical inflammation, was found to be increased in patients with type 1 diabetes in ourstudy. In addition, IL-18 level was observed to be related with acute and chronichyperglycemia and HDL-cholesterol levels. There was no clear relationship between IL-18,TNF-alpha and IL-6 levels and microvascular complications.