Comparison of Two Autoimmune Dysglycemia Syndromes: Insulin Autoimmune Syndrome (IAS) and Type B Insulin Resistance Syndrome (B-IRS).

Insulin autoimmune syndrome (IAS) and type B insulin resistance syndrome (B-IRS) are rare autoimmune dysglycemia syndromes, but their treatment and prognosis are different. This study aimed to provide a basis for the clinical differential diagnosis of IAS and B-IRS. This was a retrospective study of the medical records of all patients diagnosed with IAS or B-IRS between January 2006 and March 2018 at the Chinese PLA General Hospital. Demographic, clinical, biochemistry, treatment, and follow-up data were examined. There were several different biochemical parameters between IAS (n=13) and B-IRS (n=6): white blood count (WBC, 7.05±3.06 vs. 2.70±0.73×10/l, p=0.004), platelet (249±56.6 vs. 111±68.0×10/l, p<0.001), serum creatine (59.0±17.8 vs. 43.1±7.05 μmol/l, p=0.013), serum albumin (42.3±5.17 vs. 33.6±3.40 g/l, p=0.002), triglyceride (median, 1.33 (1.01, 1.93) vs. 0.56 (0.50, 0.79) mmol/l, p=0.002), plasma IgG (1183±201 vs. 1832±469 mg/ml, p=0.018), IgA (328±140 vs. 469±150 mg/ml, p=0.018), and C3 (128±23.4 vs. 45.3±13.5 mg/l, p<0.001). Fasting insulin in the IAS and B-IRS patients was high (299-4708 vs. 118-851 mU/l, p=0.106), and there was a difference in 2 h oral glucose tolerance test insulin (4217-8343 mU/l vs. 274-1143 mU/l, p=0.012). Glycated hemoglobin (HbA1c) in the B-IRS patients was higher than in IAS patients (114±14.4. vs. 40.6±8.89 mmol/mol, p<0.001). Serum insulin-like growth factor-1 (IGF-1) was lower in all B-IRS patients (25±0.00 vs. 132±52.7 ng/ml, p<0.001). Although IAS and B-IRS are autoimmune hyperinsulinemic dysglycemic syndromes, several clinical parameters (body mass index, HbA1c, WBC, platelet, albumin, triglyceride, IgG, C3, and IGF-1) are different between these two syndromes.