[The ultrastructure and function of lymphocytes in children with first detected untreated type 1 diabetes mellitus].

Flow cytometry (FACS-analysis), light and electron microscopy, and cytotoxic test were used to study the leukocytic composition, content, ultrastructure, and function of different lymphocytic populations (CD3+, CD4+, CD8+, CD20+, and CD56+ cells) in the blood of 90 children aged 8 to 15 years who had untreated new-onset type 1 diabetes mellitus. A control group consisted of 45 apparently healthy normoglycemic children. The sick children were observed to have a slight, but statistically significant reduction in the relative and absolute blood content of CD3+, CD4+, and CD56+ cells, CD4/CD8 index and particularly large granule-containing lymphocytes (the morpho-logical homologue of natural Idller (NK) cells). Ultrastructurally, CD20+4 cells (lymphocytes containing Gall's bodies) showed the signs of a high functional activity while NK cells (large granule-containing lymphocytes) exhibited a low one, which was confirmed by the decreased cytotoxic activity of these cells determined in vitro. Three-month insulin therapy leading to the restoration of the blood content of glucose and glycosylated hemoglobin fails to normalize the detected changes in the parameters of T- and NK-cell immunity.