Background: Recently, insulin analogs have become widely used for the treatment of diabetes. The aim of this
study was to determine differences in the antigenicity of insulin analogs and long-term changes in titers in
patients with type 2 diabetes.
Methods: Insulin antibodies were examined using polyethylene glycol and protein G methods in 381 patients
with type 2 diabetes.
Results: Insulin antibodieswere detected in 48 of 118 patients (40.7%)who used insulin, and insulin glargine and
aspartwere more antigenic. Insulin antibodieswere unexpectedly found in seven of 263 patients (2.7%)who had
never used insulin. Serum insulin concentrations in patients with insulin antibodies were significantly higher
than those without them. Two years after the initial evaluation, insulin antibodies were still positive in 92.7%
of patients who used insulin; while, they disappeared in all patients who had never used insulin. A patient
who stopped insulin injections 6 years ago was found to be positive for insulin antibodies at the first evaluation
as well as 2 years later.
Conclusions: Insulin glargine and aspart induced insulin antibodies more frequently, and insulin antibodies
remained in patients for a long time. Insulin antibodies should be suspected even in patients not currently on