Introduction: People with a high risk of development of type 1 diabetes, like first degree relatives, have characteristics for diabetes immunological/ or metabolic/or genetic markers. Presence of these markers in the blood increase the risk of development of clinically symptoms of the disease. The aim of the study was to evaluate the fasting level of the C-peptide, depending on immunological markers presence (anti-GAD, IAA and anti-IA2 antibodies) and usefulness of this parameter in the risk assessment of development of type 1 diabetes in the first degree relatives of autoimmunological diabetic patients.
Material and methods: The study was carried out in the group of 90 relatives in age from 13 to 65 (an average of age 33.1 ± 15.48 years old) and an average BMI 24.6 ± 4.95 kg/m² (17-38 kg/m²). The fasting level of C-peptide was marked by ELISA method, anti-GAD, IAA, anti-IA2 antibodies titres by RIA method.
Results: Lowered level of the C-peptide secretion was not observed in our study. In 22 persons (24.44%) increased of the fasting C-peptide secretion was assessed (> 2.9 ng/ml). Within this group, 7 relatives (31.8%) was positive titre of at least one of antibodies. We observed the positive correlation between C-peptide secretion and IAA (r = 0.282; p < 0.002). Until present moment no clinical symptoms of diabetes were observed in none of the persons.
Conclusions: The increase of fasting level of C-peptide can indicate compensatory increase of β cell secretion. It can indirectly prove the presence of insulin resistance in this group of people. The presence of higher level of C-peptide and positive IAA titre with no clinical symptoms of type 1 diabetes, seems to be the prognostic factor to retard of clinical symptoms of diabetes.