Enterovirus infections have been linked to type 1 diabetes in several studies. Enteroviruses also have tropism to pancreatic islets and can cause β-cell damage in experimental models. Viral persistence has been suspected to be an important pathogenetic factor. This study evaluates whether gut mucosa is a reservoir for enterovirus persistence in type 1 diabetic patients. Small-bowel mucosal biopsy samples from 39 type 1 diabetic patients, 41 control subjects, and 40 celiac disease patients were analyzed for the presence of enterovirus using in situ hybridization (ISH), RT-PCR, and immunohistochemistry. The presence of virus was compared with inflammatory markers such as infiltrating T cells, HLA-DR expression, and transglutaminase 2–targeted IgA deposits. Enterovirus RNA was found in diabetic patients more frequently than in control subjects and was associated with a clear inflammation response in the gut mucosa. Viral RNA was often detected in the absence of viral protein, suggesting defective replication of the virus. Patients remained virus positive in follow-up samples taken after 12 months’ observation. The results suggest that a large proportion of type 1 diabetic patients have prolonged/persistent enterovirus infection associated with an inflammation process in gut mucosa. This finding opens new opportunities for studying the viral etiology of type 1 diabetes.

We conclude that many metabolic factors are univariately associated with renal morphological findings in IgAN. These same factors are central in the metabolic or insulin resistance syndrome and may have a pathogenetic role in the progression of IgAN. Serum uric acid may have an independent role in development of tubulointerstitial lesions as well as being associated with inflammation in renal tissue of patients with IgAN.

Many risk factors for progression in immunoglobulin A nephropathy (IgAN) have been found. We focused on renal leukocyte infiltrations and cytokines in IgAN. The subjects were 204 IgAN patients. Renal histopathological changes were semiquantitatively graded. Expression of tubulointerstitial Leukocyte common antigen (LCA), CD3, CD68, interleukin (IL)-1beta, and IL-10 was evaluated by immunohistochemistry. These parameters were correlated with progression of IgAN. The significance of these correlations was tested by a multivariate analysis. Glomerulosclerosis, tubular atrophy, interstitial inflammation, and hyaline arteriolosclerosis correlated with progression in all patients and also in patients with initially normal serum creatinine. Tubulointerstitial LCA, CD3, CD68, and IL-1beta expression correlated with progression. CD3 had the strongest correlation. In the multivariate analysis, tubulointerstitial CD3, hypertriglyceridemia, elevated serum creatinine concentration, and interstitial fibrosis were independently associated with progressive disease in all patients, and tubulointerstitial CD3 expression and hyaline arteriolosclerosis in patients with initially normal serum creatinine. We found parameters reflecting tubulointerstitial inflammation to predict deterioration of renal function in IgAN. This was also seen in patients whose serum creatinine was normal at the time of renal biopsy. Our findings show that, an immunohistochemical evaluation of tubulointerstitial inflammation seems to be a useful tool in determining the prognosis in IgAN.

SummaryEnterovirus infections have been diagnosed more frequently in type 1 diabetic patients than in the healthy population, and enteroviruses have also been found in the pancreas of diabetic patients. Primary replication of the virus occurs in the gut, but there are no previous studies evaluating possible presence of virus in the intestine of diabetic patients. The purpose of this study was to investigate if enteroviruses can be found in small intestinal tissue of type 1 diabetic patients. Formalin-fixed, paraffin-embedded upper intestinal biopsy samples were analysed for the presence of enterovirus using in situ hybridization and immunohistochemistry. Enterovirus was detected by in situ hybridization in six (50%) of the type 1 diabetic patients (n = 12) but in none of the control subjects (n = 10, P = 0·015). Immunohistochemistry identified enterovirus in nine (75%) of the patients and one (10%) control subject (P = 0·004). The presence of the virus was confirmed by reverse transcriptionpolymerase chain reaction in one of the four patients from whom a frozen and unfixed sample was available. Intestinal morphology was normal in all study subjects. The results suggest that a substantial proportion of type 1 diabetic patients have an ongoing enterovirus infection in gut mucosa, possibly reflecting persistent enterovirus infection. This observation opens new avenues for further studies on the possible role of enteroviruses in human type 1 diabetes.

Aims/hypothesis Type 1 diabetes is caused by an immunemediated process, reflected by the appearance of autoantibodies against pancreatic islets in the peripheral circulation. Detection of multiple autoantibodies predicts the development of diabetes, while positivity for a single autoantibody is a poor prognostic marker. The present study assesses whether positivity for a single autoantibody correlates with pathological changes in the pancreas. Methods We studied post mortem pancreatic tissue of a child who repeatedly tested positive for islet cell antibodies (ICA) in serial measurements. Paraffin sections were stained with antibodies specific for insulin, glucagon, somatostatin, interferon alpha, CD3, CD68, cyclooxyge- Diabetologia (2008) nase-2 (COX-2), beta-2-microglobulin, coxsackie B and adenovirus receptor (CAR), natural killer and dendritic cells. Apoptosis was detected using Fas-specific antibody and TUNEL assay. Enterovirus was searched for using immunohistochemistry and in situ hybridisation, as well as enterovirus-specific RT-PCR from serum samples. Results The structure of the pancreas did not differ from normal. The number of beta cells was not reduced and no signs of insulitis were observed. Beta-2-microglobulin and CAR were strongly produced in the islets, but not in the exocrine pancreas. Enterovirus protein was detected selectively in the islets by two enterovirus-specific antibodies, but viral RNA was not found. Conclusions/interpretation These observations suggest that positivity for ICA alone, even when lasting for more than 1 year, is not associated with inflammatory changes in the islets. However, it is most likely that the pancreatic islets were infected by an enterovirus in this child.