Differences in B7 and CD28 family gene expression in the peripheral blood between newly diagnosed young-onset and adult-onset type 1 diabetes patients.

Type-1 diabetes (T1D) is a heterogeneous autoimmune disease, and there are pathogenetic differences between young- and adult-onset T1D patients. We hypothesized that the expressions of genes involved in costimulatory immune system pathways in peripheral blood are differently regulated in young- and adult-onset T1D. Study group I consisted of 80 children, adolescents, and young adults (age range 1.4-21.4 y; 31 controls and 49 T1D patients). Study group II consisted of 48 adults (age range 22.0-78.4 y; 30 controls and 18 T1D patients). The mRNA expression levels of CD86, CD28, CD25, CD226, CD40, BTLA, GITR, PDCD1, FoxP3, TGF-ß, ICOS, sCTLA4, flCTLA4, and CD80 were measured in peripheral blood. Genetic polymorphisms (HLA haplotypes; rs231806, rs231775, and rs3087243 in CTLA4; rs763361 in CD226; and rs706778 in CD25) and T1D-associated autoantibodies were analyzed. In group I, there was significantly lower expression of CD226 in T1D patients than in the controls. In group II, there were significantly higher expression levels of CD86 and TGF-ß in T1D patients than in the controls. In the T1D patients in group I, the upregulated CD80 expression correlated with the expression of both CTLA4 splice variants (sCTLA4 and flCTLA4). In contrast, in group II, upregulated CD86 correlated with TGF-ß and CD25. In group I, the inhibitory CD80-CTLA4 pathway was activated, whereas, in group II, the activation CD86-CD28 pathway and TGF-ß production were activated. These results emphasize the differences between young-onset and adult-onset T1D in the regulation of costimulatory pathways. These differences should be considered when developing novel treatments for T1D.

Autoantibody studies of female patients with reproductive failure.

The aim of this study was to investigate the prevalence and character of autoimmune derangements in women with reproductive failure. A total of 108 females (age range 17-43, mean 27.5 years), including 16 with primary menstrual cycle disturbances and polycystic ovaries (PCO), 20 with polycystic ovary syndrome (PCOS), 38 with endometriosis (E), and 34 with chronic anovulation, luteal phase insufficiency, subfertility or unexplained infertility (INF) were investigated. A control group of 392 women was formed from an unselected population sample (age range 17-43, mean 31.0 years). All sera were tested by indirect immunofluorescence method to assess common autoantibodies: nuclear (ANA), smooth muscle (SMA), parietal cell (PCA), thyroid microsomal (TMA), reticulin (ARA), mitochondrial (AMA) and liver/kidney microsomal autoantibodies (LKMA). Enzyme-linked immunosorbent assay was used to detect antibodies against beta2-glycoprotein I (anti-beta 2GPI) and carbonic anhydrase (anti-CA). Our results showed that 40.7% of patients' sera and 14.8% of control sera contained one or more common autoantibodies, ANA and SMA were most frequently detected (difference between two groups P<0.005). Anti-beta 2GPI were found in eight cases (7.4%), including two patients with INF but without other autoantibodies. Anti-CA were revealed in nine cases (8.3%) including patients' PCOS, E and INF. A comparison of patients' clinical data with antibody assay results did not reveal any significant associations. Our results indicate a high prevalence of autoimmune reactions in women with reproductive failure due to the most common causes PCO, PCOS and E as well as in unexplained infertility. This might reflect the propensity to develop autoimmune reactions in such patients, including pathogenic autoimmune reactions to specific target antigens.

The follow-up of asymptomatic persons with antibodies to pyruvate dehydrogenase in adult population samples.

PURPOSE: The presence of antimitochondrial antibodies (AMA), the hallmark of primary biliary cirrhosis (PBC), precedes the clinical manifestation of the disease for many years. The main mitochondrial autoantigen is the E2 component of the pyruvate dehydrogenase complex (PDC). The aim of this study was to identify anti-PDC-positive persons from two Estonian populations by different methodologies and to follow up the positive cases. METHODS: Enzyme-linked immunosorbent assay (ELISA) tests for antibodies to native PDC and recombinant PDC-E2 fusion protein were performed in 1461 persons (age range, 15-95 years) from Karksi-Nuia (plus 104 volunteers from the neighborhood) and to native PDC in 497 persons (age range, 50-91 years) from Abja-Paluoja (plus 28 volunteers from that neighborhood). Positive cases were tested with an enzyme inhibition assay. RESULTS: We identified 14 asymptomatic persons with antibodies to native PDC and/or recombinant PDC-E2 from these two population samples. Eight of the 14 were available for follow-up. Three of the 8 developed abnormal liver biochemical test results by the ninth year of follow-up. These persons also had, or developed, during the follow-up, a positive AMA immunofluorescence test, inhibitory antibodies to PDC, and anti-PDC of at least IgG and IgA class. Five of the 8 persons with low levels of anti-PDC, of only one immunoglobulin class reacting with only one PDC preparation, did not show any signs of cholestasis or changes in their immunoreactivity during follow-up. CONCLUSIONS: A significant number of asymptomatic patients found to have antibodies to PDC are at high risk of developing primary biliary cirrhosis.

The high frequency of coeliac disease among children with neurological disorders.

In the present study we have explored antigliadin (AGA) and antireticulin (ARA) antibody tests for the serological screening for coeliac disease (CD) of 206 children with neurological disorders. IgA- or/and IgG-type AGA was discovered in 17 (8.3%) patients and IgA-type ARA in one (0.5%) patient. A small intestinal biopsy was performed in all 18 antibody-positive patients, and villous atrophy compatible with CD was revealed in three cases (patients with either epilepsy, retardation of psychomotor development or Down's syndrome). The CD prevalence rate of 14.6 per 1000 (95% CI 7.0-22.2) found in the present study was higher than could have been anticipated on the basis of the results of our previous population studies, which indicate that CD occurs more frequently among children with neurological disorders (OR = 37.6; 95% CI 9.7-146.9). Whether this finding reflects certain immunopathogenic links between CD and particular neurological diseases needs to be studied further. In this study, we were unable, using indirect immunofluorescence testing, to demonstrate the presence of autoantibodies against brain tissue in CD and AGA-positive patients.

Seroprevalence of tick-borne Lyme borreliosis in a defined population in Estonia.

Sera from 200 randomly selected individuals living in Karksi Nuia, south Estonia, near an area endemic for tick-borne encephalitis and Lyme borreliosis (LB), were tested for antibodies to Borrelia burgdorferi. Antibodies were detected by enzyme-linked immunosorbent assay in 6 individuals (3%; 95% CI: 1-5%), who were middle-aged, asymptomatic anti-nuclear and anti-smooth muscle antibody negative. Our data show that there is low seroprevalence rate of antibodies to B. burgdorferi in an unselected south Estonian population.

IgA-antigliadin antibodies in patients with IgA nephropathy: the secondary phenomenon?

Circulating IgA-antigliadin antibodies (IgA-AGA) are often found in patients with IgA nephropathy (NP). IgA-AGA are sensitive markers of an abnormal immune system reaction to gluten, seen particularly in patients with celiac disease. However, a lack of IgA-antireticulin and IgA-antiendomysium antibodies and often jejunal mucosal atrophy of patients with IgA NP suggest that most patients do not have latent celiac disease. To examine the relationship between IgA-AGA and clinical data, enzyme-linked immunosorbent assays for IgA-AGA were performed in 28 patients with IgA NP and in 50 healthy persons. The results were calculated in arbitrary units (AU). The cutoff level for a negative or a positive test was found to be 60 AU, calculated according to the AGA test result (mean + 3 SD) in 50 healthy persons. The following clinical data were assessed: age, gender, disease duration, daily proteinuria, blood pressure, serum creatinine, and creatinine clearance. Control sera were negative for IgA-AGA. Positive IgA-AGA tests were observed in 14 of the 28 patients (p < 0.0001 vs. controls) and high levels of IgA-AGA (AU >90) in 6 of the 28 patients (p < 0.001 vs. controls). The mean duration of the disease of the patients with positive IgA-AGA was significantly longer as compared with the patients who had a negative antibody test. IgA-AGA correlated with age (p < 0.05, r = 0. 56), disease duration (p < 0.05, r = 0.40), and blood pressure (p < 0.05, r = 0.48). Antireticulin and antiendomysium antibody tests were negative in all patient and control sera. We conclude that IgA-AGA are associated with the progression of IgA NP. Our findings support the current concept about the pathogenesis of IgA NP, where the defective IgA production itself may be the primary and intestinal lesions as well as the production of IgA-AGA the secondary phenomenon.

High frequency of antigliadin antibodies and absence of antireticulin and antiendomysium antibodies in patients with ulcerative colitis.

Several authors have described an association between celiac disease (CD) and ulcerative colitis (UC), but this has not yet been established. The aim of our study was to examine the frequency of antigliadin antibodies (AGA), antireticulin antibodies (ARA) and antiendomysium (AEM) antibodies in the sera of patients with UC (n = 50), and to evaluate their correlation with clinical variables. Sixteen patients with irritable bowel syndrome (IBS) and 37 healthy individuals served as controls. An enzyme-linked immunosorbent assay was used for the detection of IgA- and IgG-type AGA. IgG-type ARA were determined by an indirect immunofluorescence assay (IIF) using rat kidney, liver, and stomach as antigen substrates. IgA-type AEM antibodies were measured by IIF, using cryostat sections from human umbilical cord. Seventeen of the 50 patients with UC (34%) were positive for IgA- or/and IgG-type AGA. There was no correlation between the presence of AGA and the duration or extent of the disease, or disease activity. However, 5 patients with both IgA- and IgG-types of AGA had extensive colitis. Only 2 controls (4%) were positive for IgG-AGA. ARA and AEM were not detected in any individuals studied. Since the ARA and AEM test results were negative, we conclude that none of the UC patients in this series had CD.

Results of coeliac disease screening in Estonia in 1990-1994.

In the period of 1990-94, 2895 individuals (629 children with suspicion of coeliac disease selected throughout Estonia; 700 consecutively hospitalized children; 105 children with atopic dermatitis; 1461 inhabitants of a small Estonian town) were serologically screened for coeliac disease. The enzyme-linked immunosorbent assay was used for antigliadin antibody determinations and R1-type antireticulin antibodies were detected using an indirect immunofluorescence method. Coeliac disease was diagnosed according to recent criteria recommended by the European Society for Paediatric Gastroenterology and Nutrition. Antigliadin antibody testing was positive in 44 (3.1%) of 1434 children studied, and in 33 of whom coeliac disease was confirmed. In all the coeliac patients R1-type antireticulin antibody test was positive. However, 52 (3.5%) of 1461 adults studied who did not have coeliac disease had positive antigliadin antibody test but negative antireticulin antibody test. Thus, in Estonia, the antigliadin antibody test can be used in screening for coeliac disease in children but not in adults.

Association of Helicobacter pylori and gastric autoimmunity: a population-based study.

Based on clinical studies, a negative association between Helicobacter pylori and autoimmune corpus gastritis is described. In the present investigation of an unselected population of 1461 adults we can state, however, that there exists a relationship between H. pylori infection and the development of gastric corpus autoimmunity. As confirmation for the gastric autoantibody development through molecular mimicry, a high homology (72% in 25 amino acid overlap) between the beta subunit of H. pylori urease and that of H + K + ATPase, the gastric parietal cell autoantigen, was revealed.