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Type 2 diabetes is a significant and increasing burden in adolescents and young adults. Clear strategies for research, prevention, and treatment of the disease in these vulnerable patients are needed. Evidence suggests that type 2 diabetes in children is different not only from type 1 but also from type 2 diabetes in adults. Understanding the unique pathophysiology of type 2 diabetes in youth, as well as the risk of complications and the psychosocial impact, will enable industry, academia, funding agencies, advocacy groups, and regulators to collectively evaluate both current and future research, treatment, and prevention approaches. This Consensus Report characterizes type 2 diabetes in children, evaluates the fundamental differences between childhood and adult disease, describes the current therapeutic options, and discusses challenges to and approaches for developing new treatments.

Recent evidence indicates that regulatory T cells (T(regs)) play an important role in HIV infection. However, although the gastrointestinal mucosa is a key compartment in HIV disease, no data on mucosal T(regs) in HIV infection are available. In this study, we compared the frequency of T(regs) in duodenal mucosa and peripheral blood (PB) of 13 treatment-naive and 13 suppressively treated HIV-infected patients with that of 6 patients with norovirus infection and 12 healthy controls. T(regs) were quantified by immunohistochemistry (CD3/FOXP3) and further characterized (CD25, CTLA-4, GITR) by immunohistochemistry, immunofluorescence, and fluorescence-activated cell sorting (FACS). Both the frequency and the absolute count of mucosal T(regs) were highly increased in untreated HIV patients but were normal in treated HIV patients. In contrast, in peripheral blood of HIV patients, the absolute number of T(regs) was not increased, and their frequency was only slightly elevated. In norovirus infection, frequency of mucosal T(regs) in the CD4+ T-cell subset was not elevated. The high increase in count and frequency of mucosal T(regs) seems to be a characteristic feature of untreated HIV infection, suggesting a significant contribution of T(regs) to the pathogenesis of HIV disease. Their role may be 2-edged: attenuating HIV-induced immune hyperactivation while suppressing the immune response to HIV and mucosal pathogens.

Introduction: Although systemic T-cell responses against tumor antigens and tumor infiltration by T cells have been investigated in colorectal cancer (CRC), the initiation of spontaneous immune responses in situ is not well understood. Macrophages and dendritic cells (DC) play an important role as a link between innate and adaptive immune response. The aim of the present study was to analyze macrophage and DC infiltration in CRC and to investigate whether there is a correlation to systemic T-cell response, regulatory T cell (Treg) infiltration, and survival.

CD4 ؉ CD25 ؉ regulatory T cells (Tregs) control immune responses to self-and foreign antigens and play a pivotal role in autoimmune diseases, infectious and noninfectious inflammation, and graft rejection. Since recent experimental studies have indicated that Tregs were able to ameliorate graft-versus-host disease (GvHD), we analyzed the number of infiltrating Tregs in the intestinal mucosa as one site of GvH reactivity using immunoenzymatic labeling to enumerate IntroductionDespite the prophylactic use of potent immunosuppressants, severe graft-versus-host disease (GvHD) is-besides infections-the most relevant complication after allogeneic stem cell transplantation. Immunologically, acute GvHD is characterized by an expansion of donor lymphocytes with cytotoxic reactivity against recipient histocompatibility antigens. The resulting clinical picture includes life-threatening destruction of skin, gut, and liver tissue.In acute GvHD, the transferred immune system lacks the capability to gain control over alloreactive T-cell clones. Therefore, the understanding of mechanisms by which an organism controls allo-or autoimmune reactivity is crucial for the development of successful strategies to prevent and/or control GvHD. Recently, these mechanisms have been further elucidated by the description of a distinct CD4 ϩ T-cell population with the capability to confer nonresponsiveness to T cells against autologous and allogeneic antigens. [1][2][3] These suppressor or regulatory T cells were originally described as a lymphocyte subset that prevents autoimmunity caused by neonatal thymectomy in mice 1 and are characterized by the expression of the interleukin-2 (IL-2) receptor ␣-chain (CD25). More recently, FOXP3, which encodes for a forkhead/winged helix transcription factor called Scurfin, has been identified to be a key regulatory gene required for the development and functional activity of regulatory T cells. [4][5][6][7] Tregs are able to suppress CD4 ϩ and CD8 ϩ T-cell responses to auto-and alloantigens in a contactdependent fashion. 8 In animal models, they can prevent graft rejection 2,3,9 and autoimmune diseases, 8,10 and there is also evidence that inappropriate numbers of Tregs may contribute to the development of chronic inflammatory diseases. 11 Consequently, the question has been raised whether Tregs are also capable of suppressing GvHD. Indeed, it has been shown in different murine models that freshly isolated or ex vivo-expanded donor-type CD4 ϩ CD25 ϩ Tregs are able to delay or even prevent GvH reactivity. [12][13][14][15] Consistent with this, the selective depletion of Tregs leads to an increased severity of acute GvHD in vivo. 16 In humans, however, available data are ambiguous. Whereas Clark et al found elevated numbers of CD4 ϩ CD25 high cells in the peripheral blood of patients with chronic GvHD, 17 Miura et al observed a significantly decreased FOXP3 mRNA expression in the peripheral blood of patients suffering from allogeneic or autologous GvHD. 18 Since the presence of Tregs in the peripheral blo...