Increase in Peripheral Blood Intermediate Monocytes is Associated with the Development of Recent-Onset Type 1 Diabetes Mellitus in Children

Monocytes play important roles in antigen presentation and cytokine production to achieve a proper immune response, and are therefore largely implicated in the development and progression of autoimmune diseases. The aim of this study was to analyze the change in the intermediate (CD14+ CD16+) monocyte subset in children with recent-onset type 1 diabetes mellitus (TIDM) and its possible association with clinical parameters reflecting islet beta-cell dysfunction. Compared with age-and sex-matched healthy controls, intermediate monocytes were expanded in children with TIDM, which was positively associated with hemoglobin A1C and negatively associated with serum insulin and C-peptide. Interestingly, the intermediate monocytes in TIDM patients expressed higher levels of human leukocyte antigen-DR and CD86, suggesting better antigen presentation capability. Further analysis revealed that the frequency of CD45RO+ CD4+ memory T cells was increased in the TIDM patients, and the memory T cell content was well correlated with the increase in intermediate monocytes. These results suggest that expanded intermediate monocytes are a predictive factor for the poor residual islet beta-cell function in children with recent-onset TIDM.