Teréz Szabó

Involvement of polymorphisms in the chemokine system in the susceptibility for coronary artery disease (CAD). Coincidence of elevated Lp(a) and MCP-1 -2518 G/G genotype in CAD patients

The central role of chemokines in the pathogenesis of atherosclerosis has been made clear. Recently polymorphisms in the gene regulatory region of MCP-1 and in the promoter region of RANTES have been found, which increase the expression of these chemokines. We investigated the role of these polymorphisms together with the chemokine SDF-1-801A and the chemokine receptors CCR2-64I and CCR5Delta32 mutations in 318 patients with coronary artery disease (CAD) referred to coronary bypass surgery, comparing them with 320 healthy controls. The prevalence of the MCP-1 -2518 G/G homozygotes was significantly higher among CAD patients than among controls (P<0.005; OR=2.2 (95% CI 1.25-3.92). The Lp(a) levels of CAD patients with G/G genotype were significantly higher than those in patients with G/A or A/A genotypes. No CAD patients homozygous for the CCR5Delta32 and CCR2-64I mutations have been found. The genotype distributions of the two alleles deviated from the Hardy Weinberg equilibrium in patients, indicating that the numbers of homozygotes were significantly lower than expected. The MCP-1 -2518G variant in homozygous form appears as a genetic risk factor for severe CAD. This genotype is associated with elevated Lp(a) levels in patients. Individuals homozygous for CCR2-64I or CCR5Delta32 mutations are at reduced risk for severe CAD.

High prevalence of silent celiac disease in preschool children screened with IgA/IgG antiendomysium antibodies

BACKGROUND Because of the different sensitivity and specificity of serologic tests, the search for silent celiac disease is usually performed with the combined or sequential use of several tests. Among these, the IgA-class endomysium antibody test has the highest specificity and positive predictive value, but it may overlook IgA-deficient patients. METHODS To test a new one-step screening approach, serum samples from 427 apparently healthy, 3- to 6-year-old Hungarian children were investigated for IgA-class and IgG-class endomysium antibodies using monkey esophagus and human jejunum as substrates. RESULTS Five new cases with flat mucosa were identified by strong endomysium antibody positivity and subsequent jejunal biopsy, yielding a celiac disease prevalence of 1:85. An additional child may have latent celiac disease (slight histologic changes at present). Two of the screening-detected celiac patients exhibited only IgG-class endomysium antibodies due to associated IgA-deficiency. Despite the young age of the screened population, antigliadin antibodies were positive in only three of the five celiac patients. CONCLUSIONS Prevalence of celiac disease in the study population was much higher than expected on the basis of antigliadin antibody-based studies. The screening system used detected celiac cases in which there was IgA-deficiency and those in which there was not and also those negative for antigliadin antibodies. The findings suggest the importance of the primary testing of autoantibodies in future celiac disease screening policies.

Chemokine receptor CCR2 and CCR5 polymorphisms in children with insulin- dependent diabetes mellitus

Studies have shown the important roles of several regulatory and proinflammatory cytokines in insulin-dependent diabetes mellitus (IDDM). CC-chemokine receptors CCR2 and CCR5 bind chemokines that are involved in the trafficking of leukocytes in both basal and inflammatory states. A common 32-bp deletion mutation in the CCR5 gene (CCR5Δ32) and a G-to-A nucleotide substitution in the CCR2 at position 190 (CCR2-64I) have recently been described. In the present study, we have determined the frequency of the CCR5Δ32 and CCR2-64I alleles in children with IDDM [n = 115; age 1-14 (9.3 ± 4.3) y] and in nondiabetic subjects [n = 280; age 1-14 (8.5 ± 4.5) y]. The CCR5Δ32 allele frequencies were 0.117 in children with IDDM and 0.111 in nondiabetic subjects, indicating that the deletion allele has no association with IDDM. The CCR2-64I allele frequency in children with IDDM was 0.226, which differed significantly from the allele frequency in controls (0.114, p = 0.001). The role of this mutation in IDDM cannot be explained yet, but, because CCR2 mediates the chemotaxis of CD4+ and CD8+ T cells to areas of inflammation and because these cells play important roles in insulitis, a mutation in the CCR2 gene may contribute to the susceptibility to the disease. Alternatively, the 64I allele could be a marker of a linked mutation through linkage disequilibrium. According to these results, the CCR2 gene may be a new candidate for the susceptibility locus of IDDM. However, because no IDDM locus has been identified near 3p21 until now, further investigations are needed to confirm this statement.

Lack of association between atopic eczema/dermatitis syndrome and polymorphisms in the promoter region of RANTES and regulatory region of MCP-1

Background: Chemokines play an important role in the pathophysiology of atopic eczema/dermatitis syndrome (AEDS) and allergy. Recently polymorphisms in the promoter region of RANTES (regulated on activation normal T cell expressed and secreted) and in the gene regulatory region of MCP‐1 (monocyte chemoattractant protein‐1) have been found, which increase the expression of these chemokines. The − 403A allele of the RANTES promoter region was found associated with AEDS in German children. We investigated whether the presence of these polymorphisms was associated with AEDS or allergy in Hungarian children.

Correlation between T-Cell and Mast Cell Activity in Patients with Chronic Urticaria

Background: The presence of autoantibodies reacting with the high affinity IgE receptor (FcΕRIα) usually indicates a more severe form of chronic urticaria (CU). Previously, we showed an increased lymphocyte reactivity in CU patients; however, the relation between enhanced cellular immunity and the presence of anti-FcΕRIα-specific autoantibodies has not been investigated. Methods: Cellular and humoral immune reactivity of 50 CU patients and 28 healthy controls was studied.Serum sIL-2R, neopterin, and tryptase levels were measured to assess T-cell, monocyte/macrophage and mast cell activity, respectively. Helicobacter pylori (HP)-specific IgG antibody, and IgE levels were also tested. Anti-FcΕRIα-specific autoantibody was determined by Western blotting. In vivo histamine-releasing activity of patients’ sera was assessed by the autologous serum skin test (AST). Results: 17/50 CU patients, who both had IgG-type anti-FcΕRIα-antibodies by Western blotting and a positive AST response, were classified as autoimmune CU. All patients with CU had significantly higher serum sIL-2R and tryptase levels than healthy controls (p = 0.000257, p = 0.000166, respectively), indicating T-cell and mast cell activation. Patients with higher sIL-2R levels also had higher tryptase levels; the strongest correlation was shown in the autoimmune subgroup of patients (ρ = 0.688, p = 0.002). There was a tendency towards higher tryptase levels in the autoimmune subgroup, as compared to the nonautoimmune CU patients. While the serum IgE was significantly lower in autoimmune than in nonautoimmune CU (p = 0.000836), there was no significant difference in their sIL-2R, neopterin and HP-specific IgG antibody levels. CU patients with a positive AST response (38/50) had significantly higher tryptase levels (p = 0.0107) when compared to the negative skin test group. Conclusions: The significant correlation between sIL-2R and tryptase levels in patients with CU indicates that T cell activation is proportional to mast cell degranulation in these patients. The increased level of tryptase in autoimmune CU may suggest more severe disease.

Functional and structural properties of Na+/K+-ATPase enzyme in neonatal erythrocytes

The Na+/K+‐pump is the main regulator enzyme of intracellular monovalent cation concentration. There are only limited data available concerning its structure and function in healthy neonates, in comparison with data available regarding its structure and function in children.

Infection and autoimmunity: Lessons of animal models

While the key initiating processes that trigger human autoimmune diseases remain enigmatic, increasing evidences support the concept that microbial stimuli are among major environmental factors eliciting autoimmune diseases in genetically susceptible individuals. Here, we present an overview of evidences obtained through various experimental models of autoimmunity for the role of microbial stimuli in disease development. Disease onset and severity have been compared in numerous models under conventional, specific-pathogen-free and germ-free conditions. The results of these experiments suggest that there is no uniform scheme that could describe the role played by infectious agents in the experimental models of autoimmunity. While some models are dependent, others prove to be completely independent of microbial stimuli. In line with the threshold hypothesis of autoimmune diseases, highly relevant genetic factors or microbial stimuli induce autoimmunity on their own, without requiring further factors. Importantly, recent evidences show that colonization of germ-free animals with certain members of the commensal flora [such as segmented filamentous bacteria (SFB)] may lead to autoimmunity. These data drive attention to the importance of the complex composition of gut flora in maintaining immune homeostasis. The intriguing observation obtained in autoimmune animal models that parasites often confer protection against autoimmune disease development may suggest new therapeutic perspectives of infectious agents in autoimmunity.

Determination of H+/K+-ATPase activity in human gastric biopsy specimens.

Abstract The aim of our work was to develop a method to determine the the H+/K+-ATPase activity of human gastric biopsy samples. Our method is based on the phosphatase activity and the K+-induceable property of the enzyme. K+-induceable pNPPase activity was determined from homogenated corpus and antrum biopsy samples. H+/K+-ase activity was calculated as the difference between the corpus and antrum K+-induceable pNPPase activities. Quality control measurements were done during 20 successive days from pooled homogenates. The total, between-day and between-run, within-day and within-run coefficients of variations were between 10 and 16%. The healthy mean and reference range of K+-induceable pNPPase activity in the corpus was 95.8 (95% CI: 83.4–108.2 mU/mg protein); in the antrum it was 28.3 (21.6–35.0) mU/mg protein. The calculated H+/K+-ATPase activity was 67.2 (56.9–77.5) mU/mg protein. The measured activities were independent of the age and gender. Summarizing our results we have concluded, that our novel method might be a potential tool to gather data about the functional acid producing capability of human gastric mucosa.

Na + /K + -ATPase isoforms in neonatal erythrocytes: a possible explanation for higher digoxin tolerance of the newborn

The aim of our study was to test, whether the different digoxin sensitivity of the neonates and children can be explained by the different functional properties of the Na+/K+ -ATPase enzyme. The activity, ouabain sensitivity and isoform composition of erythrocyte Na+/K+-ATPase of 53 healthy full term neonates (1-5 postnatal days) and that of 61 healthy children (6-38 months) were compared. The enzyme activity was elevated in neonates (mean±SEM: 429.2±17.1 vs 295.5±10.2 nmol ATP/mg prot*h-1, p<0.001). 150 value for ouabain inhibition was also higher (1.5±0.1*10.6 vs 0.96±0.1*10.6 mol/1, p<0.05). In neonates the expression of enzyme alpha subunits(1.16±0.1 vs 75±0.03, p<0.001) and the alpha1/alpha2 subtypes-ratio (4.14±0.21 vs 2.02±0.16, p<0.01) was higher than in children.