Enzyme-linked immunosorbent assay of 3 Screen Islet Cell Autoantibody in patients with autoimmune thyroid disease

BACKGROUND In recent years,the emergence of multiplex technology that can simultaneously measure multiple anti-islet autoantibodies has become particularly valuable for the staging and early diagnosis of immune-mediated type 1 diabetes(T1D).While it has been established that 20%-30%of T1D patients suffer from autoimmune thyroid disease(AITD),there is limited available data regarding the presence of anti-islet autoantibodies in AITD patients.Among commercially available anti-islet autoantibodies,glutamic acid decarboxylase 65 autoantibodies(GADAs)are often the first marker measured in general clinical practice.AIM To investigate the frequency of anti-islet autoantibodies in AITD patients.METHODS Our study involved four hundred ninety-five AITD patients,categorized into three distinct groups:AITD with T1D(n=18),AITD with phenotypic type 2 diabetes(T2D)(n=81),and AITD without diabetes(n=396),and the enzyme-linked immunosorbent assay(ELISA)was employed to determine the frequencies of 3 Screen Islet Cell Autoantibody(3 Screen ICA),GADA,insulinoma-associated antigen-2 autoantibodies(IA-2As),and zinc transporter 8 autoantibodies(ZnT8As)within these groups.RESULTS The frequency of 3 Screen ICA in AITD patients with T1D,T2D,and those without diabetes were 88.9%,6.2%,and 5.1%,respectively,with no significant difference seen between the latter two groups.Notably,the frequency of 3 Screen ICA was 11.1%higher in AITD patients with T1D,1.3%higher in AITD patients with T2D,and 1.1%higher in AITD patients without diabetes compared to GADA,respectively.Furthermore,12.5%,20.0%,and 20.0%of the 3 Screen ICA-positive patients were negative for GADA.Additionally,1.3%of the AITD patients who tested negative for 3 Screen ICA in both the AITD with T2D and non-diabetic AITD groups were found to be positive for individual autoantibodies.Among the 3 Screen ICA-positive patients,there was a significantly higher proportion of individuals with multiple autoantibodies in AITD patients with T1D compared to those without diabetes(37.5%vs 5.0%,P<0.05).However,this proportion was similar to that in AITD patients with T2D(20.0%).Nevertheless,there was no significant difference in 3 Screen ICA titers between AITD patients with T1D and those without diabetes(436.8±66.4 vs 308.1±66.4 index).Additionally,no significant difference in 3 Screen ICA titers was observed between Graves’disease and Hashimoto’s thyroiditis in any of the groups.CONCLUSION Our findings reveal that some AITD patients without diabetes exhibit 3 Screen ICA titers comparable to those in AITD patients with T1D.Thus,3 Screen ICA outperforms GADA in identifying latent anti-islet autoantibody-positive individuals among AITD patients.