Fulminant type 1 diabetes patients display high frequencies of IGRP-specific type 1 CD8+ T cells.

The role of cellular autoimmunity in the pathogenesis of fulminant type 1 diabetes (FT1D) remains largely unknown. In this study, we performed an integrated assay using peripheral blood mononuclear cells to determine the islet antigen-specific CD8+ T cell responses in FT1D and compare the responses among acute-onset T1D (AT1D) and slowly progressive T1D (SP1D). IGRP- and ZnT8-specific IL-6, G-CSF, and TNF-α responses were significantly upregulated in patients with FT1D, while IGRP- and ZnT8-specific IP-10 responses were significantly upregulated in patients with AT1D than in non-diabetics (ND). Furthermore, the frequencies of IGRP-specific type 1 CD8+ cytotoxic T (Tc1) cells were significantly higher in the FT1D group than in the ND, SP1D, and AT1D groups. Additionally, IGRP-specific Tc1 cells were more abundant in the FT1D with HLA-A2 group than in the FT1D without A2 group. In conclusion, our study suggests that IGRP-specific CD8+ T cells significantly contribute to the pathogenesis of FT1D.

Distinct Phenotypes of Islet Antigen-Specific CD4+ T Cells Among the 3 Subtypes of Type 1 Diabetes.

CONTEXT: Type 1 diabetes (T1D) is classified into 3 subtypes: acute-onset (AT1D), slowly progressive (SP1D), and fulminant (FT1D). The differences in the type of cellular autoimmunity within each subtype remain largely undetermined. OBJECTIVE: To determine the type and frequency of islet antigen-specific CD4+ T cells in each subtype of T1D. PARTICIPANTS: Twenty patients with AT1D, 17 with SP1D, 18 with FT1D, and 17 persons without diabetes (ND). METHODS: We performed an integrated assay to determine cellular immune responses and T-cell repertoires specific for islet antigens. This assay included an ex vivo assay involving a 48-hour stimulation of peripheral blood mononuclear cells with antigen peptides and an expansion assay involving intracytoplasmic cytokine analysis. RESULTS: The results of the ex vivo assay indicated that glutamic acid decarboxylase 65 (GAD65)-specific interleukin-6 and interferon-inducible protein-10 (IP-10) responses and preproinsulin (PPI)-specific IP-10 responses were significantly upregulated in AT1D compared with those of ND. Furthermore, GAD65- and PPI-specific granulocyte colony-stimulating factor responses were significantly upregulated in FT1D. Expansion assay revealed that GAD65- and PPI-specific CD4+ T cells were skewed toward a type 1 helper T (Th1)- cell phenotype in AT1D, whereas GAD65-specific Th2 cells were prevalent in SP1D. GAD65-specific Th1 cells were more abundant in SP1D with human leukocyte antigen-DR9 than in SP1D without DR9. FT1D displayed significantly less type 1 regulatory T (Tr1) cells specific for all 4 antigens than ND. CONCLUSIONS: The phenotypes of islet antigen-specific CD4+ T cells differed among the three T1D subtypes. These distinct T-cell phenotypes may be associated with the manner of progressive ß-cell destruction.

Impact of glycemic variability on the levels of endothelial progenitor cells in patients with type 1 diabetes.

OBJECTIVE: A reduction in endothelial progenitor cell (EPC) count is considered to correlate with cumulative cardiovascular risk factors including hyperglycemia. This study was conducted to elucidate the influence of glycemic variability on EPC count in patients with diabetes. METHODS: In study 1, we examined the number of EPCs in 57 patients with type 1 diabetes and 43 patients with type 2 diabetes. The number of EPCs (CD34+, CD34+CD133+, CD34+CD309+, and CD34+CD133+CD309+) was counted as the number of cells per 106 events. In study 2, we examined 37 outpatients with type 1 diabetes without macrovascular complications. We assessed associations between EPC count and seven parameters of glycemic variability (blood glucose standard deviation, mean amplitude of glycemic excursion, J index, M value, mean of daily differences, low blood glucose index, and high blood glucose index), as measured by continuous glucose monitoring. We further analyzed the correlation between EPC count and the carotid intima-media thickness (IMT) in 24 patients. RESULTS: In study 1, the number of circulating CD34+ and CD34+CD133+ cells was significantly decreased in patients with type 1 diabetes relative to that in patients with type 2 diabetes (p = 0.020 and 0.036, respectively). In study 2, a univariate analysis showed that the J index was negatively correlated with logCD34+ (r = -0.342, p = 0.039). LogCD34+ was significantly negatively associated with the max IMT (r = -0.486, p = 0.012) and the mean IMT (r = -0.503, p = 0.016). CONCLUSIONS: An increase in the J index, which reflects both hyperglycemia and glycemic variability, is associated with a reduction in the EPC count, which might result in the progression of diabetic vascular complications.

Antibody to CMRF35-Like Molecule 2, CD300e A Novel Biomarker Detected in Patients with Fulminant Type 1 Diabetes.

AIMS/HYPOTHESIS: Fulminant type 1 diabetes (FT1D) is a distinct subtype of type 1 diabetes and is fatal without immediate diagnosis and treatment. At present, there are no biomarkers for early and predictive detection of FT1D. METHODS: First, we analyzed a total of 6 serum samples from 3 patients with FT1D (1 sample in the acute and 1 in the sub-acute phases from each patient) by seromic analysis. Second, titres of the antibody were measured by ELISA in sera from 30 patients with FT1D (both in the acute and sub-acute phases), 13 patients with FT1D in the chronic phase, 32 patients with autoimmune type 1 (type 1A) diabetes (T1AD), 30 patients with type 2 diabetes (T2D), 23 patients with autoimmune thyroid disease (AITD) and 31 healthy control subjects (HC). RESULTS: Seromic analysis revealed 9 antibodies which showed high signals from all 3 patients with FT1D in the acute phase. Among them, the titre of anti-CD300e antibody was significantly higher in FT1D patients in the acute phase than that in T1AD, T2D, AITD patients and HC, as determined by ELISA (P<0.01, respectively). The titre of anti-CD300e antibody was also higher in FT1D in the acute phase than that in the sub-acute phase (P = 0.0018, Wilcoxon signed-rank test). The titre of anti-LGALS3 antibody in FT1D patients in the acute phase did not differ from that in patients with FT1D in the sub-acute phase, T1AD, T2D, AITD and HC. CONCLUSION/INTERPRETATION: The titre of a novel antibody, anti-CD300e, was high in sera from patients with FT1D. This antibody might be a diagnostic marker and provide new insight into the pathogenesis of FT1D.

Glycaemic instability correlates with a hyperglucagonaemic response in patients with type 1 diabetes without residual beta-cell function.

We investigated the association between arginine-stimulated glucagon secretion (AUCIRG) and several parameters of glycaemic variability in 12 patients with type 1 diabetes without residual beta-cell function. AUCIRG positively correlated with the SD and mean amplitude of glycaemic excursions, thus glucagon might contribute to glycaemic instability, independent of endogenous insulin.

Low CTLA-4 expression in CD4+ helper T-cells in patients with fulminant type 1 diabetes.

Fulminant type 1 diabetes is a novel subtype of type 1 diabetes characterized by a remarkably abrupt onset of insulin-deficient hyperglycemia. An accelerated immune reaction has been suggested as the cause of markedly rapid beta cell loss in this disease, but the precise mechanism has not been clarified. We analyzed the expression of cytotoxic T lymphocyte antigen 4 (CTLA-4) in CD4(+) helper T-cells in 16 patients with fulminant type 1 diabetes, 14 patients with type 1A diabetes, 10 patients with type 2 diabetes and 20 normal control subjects. There was a significant reduction in CTLA-4 expression in CD4(+) helper T-cells from patients with fulminant type 1 diabetes (P<0.05) compared with the other three groups. Low CTLA-4 expression was also observed in both CD4(+)CD25(high) T-cells and CD4(+)CD25(-) T-cells. There was a significant negative correlation between the proliferation of CD4(+)CD25(-) T-cells and the levels of CTLA-4. Intracellular expression of CTLA-4 in CD4(+) helper T-cells was not correlated with two CTLA-4 polymorphisms. In conclusion, the expression of CTLA-4 in CD4(+) helper T-cells was low in patients with fulminant type 1 diabetes.