Low serum TNF-alpha levels in subjects at risk for type 1 diabetes

Recent enterovirus infection in type 1 diabetes: evidence with a novel IgM method

Enterovirus (EV) infection has been associated with Type 1 (T1D) diabetes and on a few occasions virus could be isolated at onset of the disease. Using two such isolates as antigens in a quantitative PCR enhanced immunoassay (T1D-EV-QPIA) we have measured IgM antibodies against such potentially diabetogenic viruses in serum from 33 newly diagnosed T1D children, 24 siblings, and 27 healthy children. Sera were also analysed with regard to autoantibodies against GAD65, the cytokine TNF-alpha and the chemokine IP-10. EV-RNA detection was performed on peripheral blood mononuclear cells (PBMC). IgM antibodies against this "new" EV antigen were more frequent in serum from T1D children than in serum from siblings and/or controls (P < 0.001). EV-RNA was detected more frequently in PBMC from T1D children than in healthy control children (P < 0.001) and also compared to the siblings (P < 0.003). The cytokine TNF-alpha was less frequently detected in serum from the T1D children compared with serum from siblings and/controls (P < 0.001). A positive correlation was found between the results obtained with the T1D-EV-QPIA and the EV-PCR (P < 0.001). These findings are in line with earlier findings of an increased frequency of enteroviral infections in newly diagnosed T1D patients. In addition, we found that T1D children at onset of the disease had lower frequencies of the chemokine TNF-alpha in their serum than age- and sex-matched controls had, suggesting an impaired immune response.

The activity of N-acetyl-beta-D-glucosaminidase and tumor necrosis factor-alpha at early stage of diabetic retinopathy development in type 1 diabetes mellitus children

OBJECTIVE

The assessment of the clinical significance of TNF-alpha, IL-10 and NAG with its A and B isoforms concentrations in children with DM type 1 for the detection of early stages of both diabetic retinopathy and nephropathy.

PATIENTS AND METHODS

One hundred and two children with DM type 1 and 35 healthy controls were analyzed. Levels of TNF-alpha, IL10 and total NAG enzyme activity with its A and B isoforms were measured in serum and urine of all participants.

RESULTS

Children with diabetic retinopathy had a significantly higher levels of TNFalpha in serum (P=0.01) in comparison to those without retinopathy. The activity of NAG (P=0.002) and its isoform A (P=0.006) and isoform B (P=0.001) were significantly higher in children with diabetic retinopathy in comparison to those without this complication. Conversely, within the group with retinopathy, more children had detectable concentrations of IL10 in serum as compared to those without retinopathy (P=0.01).

CONCLUSIONS

These results suggest that NAG activity and TNF-alpha concentration in diabetic retinopathy patients might show a relationship with a degree of renal glomeruli epithelial cells and renal proximal tubules damage.

No evidence of autoimmunity in 6-year-old children immunized at birth with recombinant hepatitis B vaccine

OBJECTIVES

Taking into account that genetic predisposition, marked by human leukocyte antigen (HLA) class I and II genes, augments the probability of developing an autoimmune disorder after a triggering vaccination, as largely debated, we investigated the frequency of autoantibody production after recombinant hepatitis B vaccine (rHBv) in 6-year-old children immunized at birth to evaluate an association between autoimmune disorders and hepatitis B virus vaccination.

METHODS

We investigated the presence of autoantibodies in 210 6-year-old children who were immunized at birth with rHBv: 200 showed anti-hepatitis B surface antigen concentrations > or =10 mUI/mL at seroconversion (responders), and 10 were nonresponders. Data were compared with those obtained in 109 unvaccinated children. All participants were screened for the presence of antinuclear antibodies (ANAs), anti-DNA, antimitochondrial, anti-liver/kidney microsomal, antireticulin, anti-smooth muscle (SMA), and antiribosomal antibodies. All participants were also screened for the presence of antithyroid antibodies, such as antithyroglobulin and antiperoxidase, and for antibodies found in type 1 diabetes, such as tyrosine phosphatase (IA-2A) and glutamic acid decarboxylase (GADA). HLA typing was extended to all 10 nonresponders.

RESULTS

Autoantibodies were found in 16 of the 200 responders: ANAs were found in 12 (6%), smooth muscle antibodies were found in 4 (2.0%), and antireticulin antibodies and endomysial antibodies were found in 1 girl with ANAs. Antithyroid antibodies, IA-2A, and GADA were not present in any of the participants. No significant difference was found in the frequency of autoantibodies between vaccinated and control children. Three of the 10 nonresponder children were SMA-positive (30% vs 2% of responders); they also carried the supratype HLA-C4AQ0,DRB1*0301,DQB1*02. A family history for autoimmune disorders was present in 3 (18%; 95% confidence interval [CI]: 4.0%-45.6%) of the 16 responder infants with autoantibodies, in 15 (8.4%; 95% CI: 4.6%-13.1%) of responder children without autoantibodies, and in 1 (10%) of the 10 nonsreponder children.

CONCLUSIONS

From our data, vaccination with rHBv given during the neonatal period does not seem to increase autoantibody production in a 6-year-old children. Autoantibodies, referred to as natural autoantibodies, can be found in healthy participants, but their significance is unclear. These autoantibodies often cross-react with bacteria or tumor antigens, suggesting their importance in innate immunity. It has been demonstrated in an animal model that self-antigen can promote B-cell accumulation, and that a significant proportion of natural autoantibodies is the product of this self-antigen- dependent process. Consequently, it has been speculated that self-antigens play a positive role in recruiting B cells as a part of innate immunity, but this process carries a potential risk for unregulated growth. Spreading of the immune response is a common theme in organ-specific and systemis autoimmune diseases, and this could be initiated by exogenous agents, in genetically susceptible hosts, owing to molecular mimicry of natural antigen. Moreover, 3 (18%) of the 16 children who had autoantibodies had a family history of autoimmume diseases. Thus, it is apparent that susceptibility to autoimmunity is determined by genetic factors rather than by vaccine challenge. Among all the children considered, only 1 girl (0.5%) developed celiac disease, reflecting the prevalence described in the literature. GADA and IA-2A were not found in our children; this observation is in agreement with data showing that type 1 diabetes risk may not be altered by vaccinations administered during childhood. On the contrary, a high frequency (30%) of autoantibodies, in particular SMA, was observed in the nonresponder children. The 3 SMA-positive children carried the HLA-C4Q0,DRB1*0301,DQB1*02 haplotype, a well-known predisposing factor for autoimmune disorders. On the other hand, the presence of autoantibodies to smooth muscle is known to be common in hepatitis B infection, and, it has been shown that cross-reactive immunity targeting homologous self-protein may partly account for autoantibody production. Although hepatitis B vaccination given during the neonatal period does not increase autoantibody production in 6-year-old immunized children, we deem useful a more prolonged follow-up for these nonresponder children carrying certain HLA haplotypes (such as C4AQ0,DRB1*0301,DQB1*02), particularly because most autoimmune diseases do not develop until later in life.