phosphorus-radioisotopes and Diabetes-Mellitus--Type-1

Involvement of gut immune system has been implicated in the pathogenesis of type 1 diabetes. However, few studies have been performed on the gut mucosa from patients with type 1 diabetes. Thus, we characterized the stage of immune activation in jejunal biopsy samples from 31 children with type 1 diabetes by immunohistochemistry, in situ hybridization, and RT-PCR. We found enhanced expressions of HLA-DR, HLA-DP, and intercellular adhesion molecule-1 by immunohistochemistry even on structurally normal intestine of patients with type 1 diabetes and no signs of celiac disease. In addition, the densities of IL-1 alpha- and IL-4-positive cells detected by immunohistochemistry and IL-4 mRNA-expressing cells evaluated by in situ hybridization were increased in the lamina propria in patients with type 1 diabetes and normal mucosa. Instead, the densities of IL-2, gamma-interferon (IFN-gamma), and tumor necrosis factor alpha-positive cells, the density of IFN-gamma mRNA positive cells, and the amounts of IFN-gamma mRNA detected by RT-PCR correlated with the degree of celiac disease in patients with type 1 diabetes. Our study supports the hypothesis that a link exists between the gut immune system and type 1 diabetes.

Topics: Adolescent; Antibodies; Child; Child, Preschool; Diabetes Mellitus, Type 1; Female; Gene Expression; Genotype; Histocompatibility Antigens Class II; HLA Antigens; Humans; Immunohistochemistry; In Situ Hybridization; Intercellular Adhesion Molecule-1; Interferon-gamma; Interleukin-1; Interleukin-2; Interleukin-4; Intestinal Mucosa; Jejunum; Ki-67 Antigen; Male; Phosphorus Radioisotopes; Receptors, CCR4; Receptors, CCR5; Receptors, Chemokine; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Necrosis Factor-alpha

A 6-yr-old boy presented with muscle weakness, lactic acidemia, and insulin-dependent diabetes mellitus (IDDM). Using PCR and restriction enzyme analysis, he was found to have the classical A3248G mitochondrial DNA (mtDNA) mutation frequently associated with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). The mutation was confirmed by sequencing muscle mtDNA. The mutation in mtDNA from muscle, lymphoblasts, and blood was clearly demonstrable by standard methods using ethidium bromide staining. His mother also had IDDM, but no A3243G mutation could be detected in her blood or transformed lymphoblasts using the same PCR technique. When PCR was carried out in the presence of [32P]deoxycytidine triphosphate, subsequent autoradiography detected the presence of the mutation at low levels in mtDNA from the mother's lymphoblasts and blood. Study of the mother's muscle showed a mitochondrial myopathy, despite the fact that she was asymptomatic. We emphasize that the increased sensitivity of radiolabeled PCR may be necessary to detect small percentages of heteroplasmic A3243G mtDNA mutation in blood from diabetic subjects. Otherwise the incidence of mtDNA mutations in both IDDM and non-insulin dependent diabetes may be underestimated.

Topics: Adult; Autoradiography; Child; Diabetes Mellitus, Type 1; DNA, Mitochondrial; Electron Transport; Ethidium; Female; Fluorescent Dyes; Humans; Male; MELAS Syndrome; Microscopy, Electron; Mitochondria, Muscle; Muscles; Mutation; Phosphorus Radioisotopes; Polymerase Chain Reaction