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R Uibo

Publications and source records attributed to R Uibo.

At least 37 records · Page 2Linked to original sources
PubMed1999

Comparison of enterovirus-specific cellular immunity in two populations of young children vaccinated with inactivated or live poliovirus vaccines.

Enterovirus-specific cellular immunity was studied in Estonian and in Finnish children at the age of 9 months. The aim was to evaluate the level of responsiveness in two neighbouring countries with different poliovirus immunization practices and striking differences in the incidence of insulin-dependent diabetes mellitus (IDDM), a disease in which early enterovirus infections are an aetiological risk factor. The Estonian children immunized with live attenuated polio vaccine had stronger T cell responses to coxsackievirus B4 and poliovirus type 1 when compared with Finnish children immunized with inactivated polio vaccine (median stimulation indices 10.4 and 6.3 in Estonian children and 1.9 and 2.9 in Finnish children, respectively; P < 0.05). Lymphocytes stimulated by poliovirus type 1 antigen expressed interferon-gamma (IFN-gamma) mRNAs, which strongly correlated with the level of proliferation responses. Lymphocytes of Estonian children had a tendency towards stronger expression of IFN-gamma upon poliovirus challenge when compared with Finnish children. The number of children who had experienced coxsackievirus B infections, as determined by the presence of neutralizing antibodies, did not differ between Estonian and Finnish children. The results show that Finnish children have weaker cellular immunity against enteroviruses at the age of 9 months compared with Estonian children at the same age. This is most probably due to the difference in polio vaccination schedules; in Estonia live poliovirus vaccine is used and given at earlier ages than the inactivated vaccines in Finland. This leads to stronger T cell immunity which cross-reacts with other enterovirus serotypes. This may explain the lower incidence of IDDM in Estonia by providing effective protection against diabetogenic enterovirus strains in Estonian children.

Antibodies, Viral↗
PubMed1999

Polymorphisms in tumour necrosis factor and adhesion molecule genes in patients with inflammatory bowel disease: associations with HLA-DR and -DQ alleles and subclinical markers.

BACKGROUND: When investigating susceptibility to inflammatory bowel disease (IBD), a multifactorial disorder with a genetic predisposition, polymorphisms of molecules with immunoregulatory function are of potential interest. This is the first time that the polymorphisms of HLA-DR and -DQ, tumour necrosis factor (TNF), E-selectin (CD62E), L-selectin (CD62L), and intercellular adhesion molecule 1 (ICAM-1, CD54) were determined in Estonians, a population with a low IBD incidence rate, and their occurrence investigated in subgroups of a total of 53 IBD patients. METHODS: The reverse hybridization principle and sequence specific primers were used for HLA genotyping. To analyse the TNF and adhesion molecule polymorphisms, the polymerase chain reaction with subsequent restriction fragment length polymorphism or single-strand conformation polymorphism method was used. RESULTS: In the subgroup of antineutrophil cytoplasmic antibody (ANCA)-positive ulcerative colitis (UC) patients we found a higher frequency of the TNF2 (20.8% versus 0.0% in ANCA-negative UC patients, P = 0.051) and HLA-DRB1*15 allele (35.4% versus 15.7% in controls; P = 0.004). Of ANCA-positive UC patients 87.5% were carriers of one of these alleles (22.2% among ANCA-negative UC patients (P<0.001, Pc = 0.039) and 51.4% among controls (P = 0.002). Specific typing of HLA-DRB1*15 alleles showed that the HLA-DRB1*1501 allele was responsible for the HLA-DRB1*15 association with ANCA-positive UC. Associations of ICAM-1, E-selectin, or L-selectin polymorphisms with IBD were not found. CONCLUSIONS: TNF2 and HLA-DRB1*15 alleles were associated with ANCA-positive UC in the investigated population. ANCA might be a useful marker, at least in some ethnic groups, for dividing IBD patients into genetically more homogeneous subgroups.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1999

An 18-year follow-up study of chronic gastritis and Helicobacter pylori association of CagA positivity with development of atrophy and activity of gastritis.

BACKGROUND: We wanted to evaluate the course of chronic gastritis and its association with Helicobacter pylori and CagA seropositivity in an adult sample from Saaremaa (Estonia) during an 18-year follow-up. METHODS: Seventy persons (31 men, 39 women; median age, 57.5 years) from a primary sample of 304 subjects endoscoped in 1979 were reinvestigated by endoscopy and biopsy in 1997. The state of the gastric mucosa and the presence of H. pylori in histologic sections from the antrum and corpus were assessed both in 1979 and 1997 in 66 subjects in accordance with the Sydney system, and H. pylori status in all 70 subjects was determined with the enzyme-linked immunosorbent assay (ELISA). Anti-CagA IgGs were determined with the ELISA, using the recombinant fragment of CagA. RESULTS: During an 18-year follow-up 11% of the subjects developed atrophy in the antrum, whereas 35% developed it in the corpus. Development of atrophy in the corpus and the appearance of intestinal metaplasia in the antrum were associated with increased activity of gastritis both in the initial and last follow-up biopsies. Anti-CagA positivity was found in 71% of H. pylori-seropositive persons (94% of subjects). There was a significant association between CagA positivity and the activity of gastritis, the presence of atrophy or damage to surface epithelial cells in the antrum and in corpus mucosal biopsy specimens at the last follow-up endoscopy. CONCLUSION: The CagA-positive strains of H. pylori enhance the development of atrophic gastritis compared with CagA-negative strains.

Antigens, Bacterial↗
PubMed1999

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.

Adolescent↗
PubMed1999

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.

Adult↗
PubMed1998

A cytotoxic T lymphocyte antigen-4 (CTLA-4) gene polymorphism is associated with autoimmune Addison's disease in English patients.

OBJECTIVE: Recent studies have demonstrated an association between a microsatellite polymorphism of the CTLA-4 gene, specifically a 106 base pair allele, and both Graves' disease and autoimmune hypothyroidism. The aim of the present study was to determine whether the same polymorphism of the CTLA-4 gene was associated with autoimmune Addison's disease. DESIGN AND PATIENTS: We analysed a microsatellite polymorphism (variant lengths of a dinucleotide (AT)n repeat) within exon 3 of the CTLA-4 gene in the following groups: 21 English patients with non-associated Addison's disease, 18 with autoimmune polyglandular syndrome type 2 (APS2) and 173 healthy control subjects; 26 Norwegian patients with non-associated Addison's disease, 9 with autoimmune polyglandular syndrome type 1 (APS1), 17 with APS2 and 100 controls; 3 Finnish patients with non-associated Addison's disease, 5 with APS2 and 71 controls; 10 Estonian patients with non-associated Addison's disease, 2 with APS2 and 45 controls. MEASUREMENTS: The CTLA-4 microsatellite gene polymorphisms were determined by polymerase chain reaction amplification of genomic DNA and resolution of the products on sequencing gels. RESULTS: The frequency of the 106 base pair allele was significantly increased in the groups of English patients with either non-associated Addison's disease or APS2 (P = 0.02 and 0.04, respectively), when compared to healthy controls with no clinical evidence or family history of either Addison's disease or any other autoimmune disorder. For Norwegian patients with either non-associated Addison's disease, APS1 or APS2, there was no association (P = 0.69, 0.62 and 0.97, respectively). This was also the case for Finnish patients with either non-associated Addison's disease or APS2 (P = 0.23 and 0.28, respectively) and for Estonian patients with either non-associated Addison's disease or APS2 (P = 0.34 and 0.29, respectively). CONCLUSIONS: These results indicate that differences exist in the frequency of the 106 base pair allele in different population groups and in only the English population was the 106 base pair allele associated with Addison's disease.

Abatacept↗
PubMed1998

Helicobacter pylori (H. pylori) in gastric mucosa of children with abdominal complaints: immunohistochemistry detects antigen-reactive corpus mucosa cells.

BACKGROUND: Previous morphological and serological studies of gastric Helicobacter pylori (H. pylori) colonization among Estonian children with abdominal complaints, as well as among populations of schoolchildren, have shown a high prevalence of H. pylori (49-60%). Based on published data concerning the high specificity and sensitivity of immunohistochemical detection of H. pylori, we examined the prevalence of H. pylori in gastric biopsy specimens of Estonian children by different localization and morphological type of gastritis comparing Giemsa staining with immunohistochemistry. MATERIAL AND METHODS: Formalin-fixed biopsies (107 antral, 108 corpus mucosa) of 112 children (41 boys, 71 girls, age range 1-16 years, median age 12 years) with abdominal complaints were stained with hematoxylin & eosin and Giemsa stains, as well as examined using the peroxidase antiperoxidase (PAP) method with polyclonal antibodies to H. pylori. RESULTS: Gastritis of any degree and localization was found in 84/112 (75%) children. Using Giemsa staining H. pylori were detected in 83/112 (74%) of all children, and by use of the PAP method in 55/112 (49%) (p = .001). Concordance of the results of immunohistochemical and Giemsa methods in antrum biopsies was 70%, in corpus biopsies 73%. In 12 out of 108 (11%) corpus mucosa specimens a positive staining with anti-H. pylori IgG was localized in the cytoplasma of corpus mucosal cells in the neck part of the glands. CONCLUSIONS: The prevalence of H. pylori was higher when employing the Giemsa stain in comparison with immunohistochemistry. Antibody reactivity of cells in the neck part of the corpus glands may either be due to cross-reactivity of anti-H. pylori IgG with epithelial cell epitopes, or to internalization of H. pylori by these cells, suggesting a pathogenic role of neck cells in an anti-H. pylori immune response.

Adolescent↗
PubMed1998

CagA protein seropositivity in a random sample of adult population and gastric cancer patients in Estonia.

OBJECTIVE: The prevalence of antibodies to CagA protein, associated with the risk of developing gastric cancer (GC), was studied in an Estonian adult population with a high prevalence of Helicobacter pylori (HP) infection and in a group of GC patients. DESIGN: In a representative sample of a random adult population from the South Estonian town of Karksi-Nuia, containing 199 subjects (86 M, 113 F, mean age 42.4) and in 45 (22 M, 23 F, mean age 64.5) consecutive patients with gastric adenocarcinoma, recruited during the periods 1986-87 and 1995-96 in the Hospital of Oncology, University of Tartu, anti-CagA IgG antibodies were determined by enzyme-linked immunosorbent assay (ELISA) using a recombinant fragment of CagA protein. The occurrence of anti-CagA IgG in ELISA was compared with immunoblot results for 141 subjects. RESULTS: Seropositivity to acid glycine extracted cell surface proteins of HP was 85% in the population and 91% in GC patients (p = 0.39). Anti-CagA IgG antibodies were present in 63% of the population and in 87% of GC patients (p = 0.004). The highest prevalence of anti-CagA IgG in the population sample occurred in the age group 20-29 (76%). A comparison of anti-CagA positivity evaluated by using ELISA and immunoblot showed an agreement of results in 80% of cases. CONCLUSION: HP seropositivity was similarly high in the Estonian random adult population sample and in GC patients, however, the prevalence of anti-CagA IgG was significantly higher in GC patients. Moreover, persons aged 20-29 years in the population possess the highest prevalence of anti-CagA IgG and should be given further attention with respect to the development of GC later in life.

Adenocarcinoma↗
PubMed1998

Antibodies to pyruvate dehydrogenase in primary biliary cirrhosis: correlation with histology.

Antimitochondrial antibodies to pyruvate dehydrogenase are the hallmark of primary biliary cirrhosis. Their pathogenic role has not been proven, although antibodies to pyruvate dehydrogenase are bound to biliary epithelium. The aim of this study was to characterize serum IgA antibodies to pyruvate dehydrogenase and to evaluate their response to different treatment regimens. We also compared the level of antibodies with severity of histological lesions and the data of biochemical liver tests. Serum samples were collected at baseline and after 24 months from 61 primary biliary cirrhosis patients, whereas 23 patients were treated with ursodeoxycholic acid, 20 with colchicine, and 18 with placebo. ELISA was used to detect antibodies to pyruvate dehydrogenase. IgA and IgG were separated with jacalin and protein-A, respectively. Capacity of immunoglobulins to inhibit enzymatic activity was detected by spectrophotometric observation of the rate of enzyme reaction. 49 (80.3%) of the 61 patients possessed IgA antibodies to pyruvate dehydrogenase. Significant decrease in IgA antibodies was observed only in the ursodeoxycholic acid group (p<0.05). 15 of 18 IgA preparations and all 24 IgG preparations of patients' sera were inhibitory towards pyruvate dehydrogenase (mean inhibitory percent +/-SD: 42+/-33.4% and 79+/-22.4%, respectively, at a protein concentration of 100 microg/ml). The level of serum antibodies to pyruvate dehydrogenase correlated with several histological parameters (fibrosis, inflammatory infiltrate), but not with biochemical parameters. Our data reveal that IgA antibodies to pyruvate dehydrogenase inhibit enzyme function. The correlation between antibodies to pyruvate dehydrogenase and histological parameters might suggest the pathogenic role of these antibodies.

Adult↗
PubMed1998

Autoantibodies in Estonia and Sweden, populations with different responses to allergens.

BACKGROUND: There are substantial differences in immune-mediated disease prevalence between different countries and populations which cannot be explained by genetic variability. AIMS: To compare the prevalence of antinuclear (ANA), antimitochondrial, antireticulin, liver-kidney microsomal, parietal cell, thyroid microsomal and double-stranded DNA (dsDNA) antibodies among adults aged 20-44 years in two towns, i.e. in Tartu, Estonia (n = 448) and in Uppsala, Sweden (n = 532) with a low and a high prevalence of allergy. METHODS: For autoantibody detection, standard indirect immunofluorescence tests on tissue and Chritidia lucilia antigenic preparations were used (sera were diluted starting from 1:10). RESULTS: The prevalence of ANA was lower in Tartu than in Uppsala (3 vs. 10% among males and 11 vs. 16% among females; p<0.01 and p<0.1, respectively). Furthermore, dsDNA antibody-positive cases were only identified in Uppsala. The largest difference between the two populations was revealed for IgM type ANA, both among males (1 vs. 6%; p<0.02) and females (5 vs. 11%; p<0.01). In addition, the antibody titers were lower in Tartu than in Uppsala (p<0.05). The prevalence of other autoantibodies was similar in the two towns. CONCLUSIONS: The findings could support that Th2-like immune responses are commoner in Sweden than in Estonia, as previously suggested by the higher prevalence of allergy.

Adult↗
PubMed1997

Immunoprecipitation of steroidogenic enzyme autoantigens with autoimmune polyglandular syndrome type I (APS I) sera; further evidence for independent humoral immunity to P450c17 and P450c21.

Three steroidogenic P450 cytochromes, steroid 17alpha-hydroxylase (P450c17), steroid 21-hydroxylase (P450c21) and side-chain cleavage enzyme (P450scc), have been described as autoantigens in APS I. In this study we report an immunoprecipitation assay for the detection of autoantibodies to these three enzymes using in vitro 35S-labelled antigens. Overall, 33 out of 46 (72%) patients with APS I had autoantibodies to at least one of the three proteins and each protein was recognized by patient sera with equal frequency. A higher rate of autoantibody positivity was observed in APS I patients with Addison's disease compared with patients without Addison's disease (85% versus 39%). All 11 patients with ovarian failure had anti-P450c17 or anti-P450scc antibodies. The immunoprecipitation results with P450c17, P450c21 and P450scc correlated well with the results obtained by immunoblotting assays. In addition, the steroidogenic enzymes 11beta-hydroxylase (P450c11beta), aromatase (P450arom), 3beta-hydroxysteroid dehydrogenase (3betaHSD) and adrenodoxin were studied by immunoprecipitation assay, but no reaction was found either with 46 APS I or with 26 healthy control sera. To study the suggested immunological cross-reactivity between P450c17 and P450c21 enzymes, nine APS I patient sera were preabsorbed with bacterially expressed P450c17 or P450c21 and subsequently used in immunoprecipitation assay. The absorption experiments clearly indicated that the preincubation inhibited only the reactivity of corresponding antigen, suggesting independent autoantibody response to the two enzymes. Our results suggest that the immune response to some but not to all steroidogenic enzymes is a specific feature of APS I that may be pathogenically significant.

Absorption↗
PubMed1997

A study of antimitochondrial antibodies in a random population in Estonia.

Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterized by the spontaneous destruction of the small intrahepatic bile ducts. The hallmark serologic feature of PBC is the presence of high-titer antimitochondrial antibodies (AMA). Both the incidence and prevalence of PBC varies geographically; epidemiological data may provide valuable insight regarding the pathogenic mechanisms and etiology of disease. Thus far, the majority of studies on the occurrence of PBC and AMAs have been derived from autopsy, mortality figures, or hospital admission records. The numbers reported reflect only those patients with clinical disease. To address this issue, an adult population sample representing all age groups in the village of Karksi-Nuia in southern Estonia was selected for a study of AMA incidence. This village has unique features that make it ideal for such a study. First, the village is remote and a substantial number of families have lived in the area for generations. There is also a limited influx of new families into the village, therefore providing a limited genetic repertoire. In this unselected adult population, we examined AMA incidence by both immunoblot and ELISA, using native and recombinant antigens. Of the 1461 people studied, 13 (0.89%) were AMA positive. A similar frequency (0.96%) was found among 104 persons from a neighboring village, who subsequently joined the study. Our study suggests that the presence of AMA in Estonia is in agreement with the reported incidence of less than 1% AMA in a mixed hospital population.

Adolescent↗
PubMed1996

Ursodeoxycholic acid treatment lowers the serum level of antibodies against pyruvate dehydrogenase and influences their inhibitory capacity for the enzyme complex in patients with primary biliary cirrhosis.

A two-year randomized, double-blind, placebo-controlled clinical trial used paired serum samples from 122 patients with primary biliary cirrhosis to compare the effect of ursodeoxycholic acid and colchicine on their immune parameters. IgG antibodies to pyruvate dehydrogenase, the major autoantigen in primary biliary cirrhosis, were determined by enzyme-linked immunosorbent assay and immunoblot; enzyme inhibition assay against pyruvate dehydrogenase was used to test the changes of the functional reactivity of the serum autoantibodies. Treatment with ursodeoxycholic acid decreased both the level of IgG antibodies to pyruvate dehydrogenase (P < 0.01) and the inihibitory titer of the sera for pyruvate dehydrogenase (P < 0.01). Treatment with colchicine or placebo showed no statistically significant changes in either the antibody levels or the inhibitory titers. Ursodeoxycholic acid thus alters the immune parameters of patients with primary biliary cirrhosis. The mechanism of these changes needs further investigation.

Antibodies↗
PubMed1996

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.

Adolescent↗
PubMed1995

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.

Adolescent↗
PubMed1995

Mapping thyroid peroxidase epitopes using recombinant protein fragments.

The identification of autoantibody epitopes is important to the understanding of autoimmune thyroid diseases. In the case of thyroid peroxidase antibodies (TPO-ab), recent reports have disagreed about the number and type of autoantibody epitopes found in human TPO. In order to clarify the nature of these epitopes, we used an approach that provides recombinant human TPO produced by bacterial cells. The cDNA of four slightly overlapping fragments of human TPO-TPO 1(Glu 17-Ser 227), TPO 2(Tyr 226-Thr 476), TPO 3(Glu 471-Ser 720) and TPO 4(Phe 709-Leu 993)--were amplified by polymerase chain reaction and subcloned into the expression vector pMAL. In addition, a TPO 3 species for an alternatively spliced form of TPO of 876 amino acids was constructed (TPO 3M). Each of these constructs encodes a fusion protein, in which the amino terminal portion is maltose-binding protein, followed by the sequence of the fragment of human TPO. The plasmid constructs were transformed in Escherichia coli and, after growth, bacterial cells were harvested, lysed and the lysate was passed over an amylose affinity column and eluted with maltose. Western blots were performed using 33 sera from patients with autoimmune thyroid disease (group 1) and 17 sera from patients with nodular goiter and focal thyroiditis (group 2), all positive for TPO-ab measured by radio-immunoassay; sera from 10 healthy people with no clinical evidence of thyroiditis and positive for TPO-ab measured by radioimmunoassay (group 3) and sera from 30 patients with antigastric parietal cell antibodies without signs or symptoms of thyroiditis, 16 negative for TPO-ab (group 4a) and 14 positive for TPO-ab (group 4b), were included in the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗