Healthy subjects aged between 25 and 60 (20 cases) and between 61 and 65 (5 cases), and diabetic patients with vascular damage, aged between 24 and 62 (6 cases), were tested by a new method for the detection and identification of elastin-antielastin circulating immune complexes (CIC) in human sera. Such immune complexes were found in all patients' sera and only in one of the controls (at the age of 65). Among different patients, the elastin-antielastin CIC varied in size and elastin content, showing some correlation between these two characteristics and the existence of microvascular complications, as proved by the clinical and paraclinical investigation of the patients.