Introduction and aims: Antibodies against products of elastin degradation are found in sera of all people. Presence of anti-elastin antibodies (AEAbs) and relevant antigens in circulation leads to the formation of circulating immune complexes (CIC). The aim of our study is to determine serum levels of anti-elastin antibodies unbound in CIC (free AEAbs).
Material and methods: We used a method for detection CIF-ELISA (complement-inhibiting factor-enzyme linked immunosorbent assay) in combination with ELISA to find AEAbs. The levels of free AEAbs IgG were measured in sera of 93 patients with diabetes mellitus and hypertension (mean age 61.4 ±11.3, diabetes duration 9.88 ±3.12; hypertension duration 9.28 ±4.98). These levels were compared to 42 age- and sex-matched controls.
Results: Free AEAbs IgG in patients with T2DM and AH are statistically significantly higher than these in healthy controls: 0.421 (0.328-0.572) vs. 0.240 (0.212-0.305), respectively (KW = 19.64; p < 0.0001). Group 1 (patients with microvascular complications) showed a significant increase in free AEAbs IgG in comparison with controls: 0.428 (0.343-0.591) vs. 0.240 (0.212-0.305), respectively (KW = 20.14;
p < 0.0001). Group 2 also shows higher levels of free AEAbs IgG than the control group: 0.398 (0.312-0.467) vs. 0.240 (0.212-0.305), respectively (KW = 8.88; p = 0.003). Patients with microvascular complications showed the highest levels of free AEAbs IgG. There were no significant differences between group 1 and group 2.
Conclusions: Our results show the association between the activity of elastin turnover and microvascular lesions in diabetic patients with arterial hypertension. We suggest that free AEAbs IgG mark a later “secondary” step of the autoimmunization to elastin.