Objective: To investigate the prevalence of positive thyroid antibodies in children with type 1 diabetes mellitus (T1DM) and its influencing factors.
Methods: The clinical data of T1DM children who were treated in the Children's Hospital of Zhejiang University from May 2005 to April 2011 were retrospectively studied. The relationships of thyroid globulin antibody (TGAb) and thyroid peroxidase antibody (TPOAb) with cytokines IL-2, IL-4, IL-6, IL-10, TNF and IFN-γ were evaluated, and the percentages of CD3+, CD4+ and CD8+ T-lymphocytes in peripheral blood were examined.
Results: A total of 186 T1DM children with complete data of both TGAb and TPOAb were included in the study, among whom 143 with normal TGAb and TPOAb levels and 43 (23.1%) presented with positive thyroid antibody (including 21 cases with both positive TGAb and positive TPOAb). Eighteen cases (9.7%) were diagnosed as autoimmune polyglandular syndrome type 3 variant (APS3v). Significantly more patients in the positive thyroid antibody group had a family history of diabetes than in the negative thyroid antibody group (27.9% vs 14.7%; P<0.05). The average age of the positive thyroid antibody group was 10.1±3.2 years, which was significantly greater than that in the negative thyroid antibody group (8.1±4.0 years) (P<0.05). The IL-2 level (4.48 ±1.27 pg/mL vs 2.82 ±0.84 pg/mL, P<0.05) and the percentage of peripheral CD3+ T-lymphocyte[(61±11)% vs (66±11)%; P<0.05] were also different between the positive and negative thyroid antibody groups.
Conclusions: Genetic background and abnormal function of T-lymphocytes (especially higher IL-2 level) may be involved in the elevated prevalence of positive thyroid antibody in T1DM children.