[Surface expression of costimulatory molecules CD28/CTLA-4 on peripheral blood T lymphocytes in the course of type 1 diabetes mellitus in children and adolescents].

Background: Type 1 diabetes is mediated by autoreactive - T lymphocytes recognizing pancreatic islet cell antigens. CD28/CTLA-4 costimulatory molecules participate in the transduction of the necessary signal in T lymphocytes proliferation and play an important role in the development of autoimmunological process.

Objectives: The purpose of this study was: to evaluate whether the expression of CD28, CTLA-4 molecules on peripheral blood T lymphocytes alters in the course of disease -- diabetes lasting less than 5 years and over 5 years; to assess a relationship between the percentage of CD28, CTLA-4 on T cells and the evolution of vascular complications (microalbuminuria, arterial hypertension, diabetic retinopathy).

Material and methods: The study was carried out in three groups of subjects - 60 children (aged 9-20) with diagnosed type 1 diabetes: (a) (20 n) with the disease lasting >5 years, (b) (20 n) with type 1 diabetes lasting >5 years without vascular complications, (c) (20 n) with type 1 diabetes and vascular complications (microalbuminuria, arterial hypertension, diabetic retinopathy). The control group consisted of 20 healthy volunteers (aged 6-17). The expression of adhesion molecules has been evaluated by using three-color flow cytometry (Coulter EPICS XL). HbA1c concentration has been analysed by liquid chromatography technique HPLC-Variant (Bio-Rad).

Results: In the study, the superficial expression of CTLA-4 receptor on T lymphocytes was enhanced in children with diabetes lasting <5 years (p<0.005) and over 5 years without vascular complications (p<0.01) versus healthy patients and tend to normalize in the presence of developing vascular complications In contrast, the expression of costimulatory molecule CD28 was decreased in children with type 1 diabetes lasting <5 years (p<0.05) as well as in children with developing vascular complications (p<0.01) versus the control group.