The interleukin-25 gene located in the inflammatory bowel disease (IBD) 4 region: no association with inflammatory bowel disease.

Genetic predisposition has been suggested to play an important role in the pathogenesis of inflammatory bowel diseases (IBDs). Linkage studies have identified a Crohn's disease susceptibility locus on chromosome 14 (14q11-12; IBD4). Interleukin-25 (IL-25) is a newly identified proinflammatory cytokine that has been shown to promote Th2 responses by inducing cytokines such as IL-4, IL-5 and IL-13. The IL-25 gene is located within this susceptibility region at 14q11.2. As IBDs are characterized by an imbalance of the Th1/Th2 cytokine response, we hypothesized that genetic alterations within the IL-25 gene might contribute to IBD. First, direct sequencing of the coding regions of the IL-25 gene in 40 patients with Crohn's disease or ulcerative colitis revealed only a newly reported polymorphism (c424C/A) in exon 2. Next, the frequency of this polymorphism was further investigated in 151 patients with Crohn's disease, 111 patients with ulcerative colitis, and 119 healthy controls to determine its clinical relevance. The genotypes of the c424C/A polymorphism did not reveal any significant differences between patients with Crohn's disease or ulcerative colitis and controls. Genoytype-phenotype relations in patients with Crohn's disease showed a comparable distribution of the c424C/A polymorphism in all subgroups of the Vienna classification. In summary, our data indicate that genetic alterations in the coding regions of the IL-25 gene are unlikely to play a role in IBDs, but the c424C/A polymorphism in the IL-25 gene should be investigated for a potential association with other chronic inflammatory and inherited disorders such as autoimmune diseases.

The C/C(-13910) and G/G(-22018) genotypes for adult-type hypolactasia are not associated with inflammatory bowel disease.

BACKGROUND: Lactose intolerance with adult-onset is due to the inadequate enzymatic activity of lactasephlorizin hydrolase (LPH). It is frequently seen in patients with Crohn disease, but the mechanism remains to be elucidated. Two DNA genotypes, C/C(-13910) and G/G(-22018), located upstream from the LCT locus, the gene encoding for LPH, were recently identified as representing genetic markers for lactose intolerance. We utilized these two DNA genotypes to study their role in inflammatory bowel disease. METHODS: We investigated the prevalence of these two DNA variants using specific restriction enzyme digest assays in 166 patients with Crohn disease, in 120 healthy first-degree relatives of Crohn disease patients, in 63 patients with ulcerative colitis and in 187 healthy individuals. RESULTS: The analysis revealed a frequency of 21.4% of the 2 genotypes for adult-type hypolactasia in our studied German cohort of healthy individuals, which is higher than previously reported (15%) based on the hydrogen (H2) breath test. This might indicate a higher sensitivity of genotyping, but it has to be confirmed in larger cohorts. No significant difference was detectable in the frequency of the C/C(-13910) and G/G(-22018) genotypes in patients with Crohn disease (C/C(-13910): 21.7%; G/G(-22018): 22.3%) compared to first-degree relatives (C/C(-13910): 21.7%; G/G(-22018): 20.8%), patients with ulcerative colitis (C/C(-13910): 20.3%; G/G(-22018): 20.3%) and healthy individuals (C/C(-13910): 21.4%; G/G(-22018): 21.4%). CONCLUSION: The C/C(-13910) and G/G(-22018) genotype of adult-type hypolactasia is not associated with susceptibility to the pathogenesis of Crohn disease and ulcerative colitis.

The C/C_13910 and G/G_22018 Genotypes for Adult-type Hypolactasia are not Associated with Inflammatory Bowel Disease.

BACKGROUND: Lactose intolerance with adult-onset is due to the inadequate enzymatic activity of lactase-phlorizin hydrolase (LPH). It is frequently seen in patients with Crohn disease, but the mechanism remains to be elucidated. Two DNA genotypes, C/C_13910 and G/G_22018, located upstream from the LCT locus, the gene encoding for LPH, were recently identified as representing genetic markers for lactose intolerance. We utilized these two DNA genotypes to study their role in inflammatory bowel disease. METHODS: We investigated the prevalence of these two DNA variants using specific restriction enzyme digest assays in 166 patients with Crohn disease, in 120 healthy first-degree relatives of Crohn disease patients, in 63 patients with ulcerative colitis and in 187 healthy individuals. RESULTS: The analysis revealed a frequency of 21.4% of the 2 genotypes for adult-type hypolactasia in our studied German cohort of healthy individuals, which is higher than previously reported (15%) based on the hydrogen (H2) breath test. This might indicate a higher sensitivity of genotyping, but it has to be confirmed in larger cohorts. No significant difference was detectable in the frequency of the C/C_13910 and G/G_22018 genotypes in patients with Crohn Disease (C/C_13910: 21.7%; G/G_22018: 22.3%) compared to first-degree relatives (C/C_13910: 21.7%; G/G_22018: 20.8%), patients with ulcerative colitis (C/C_13910: 20.3%; G/G_22018: 20.3%) and healthy individuals (C/C_13910: 21.4%; G/G_22018: 21.4%). CONCLUSIONS: The C/C_13910 and G/G_22018 genotype of adult-type hypolactasia is not associated with susceptibility to the pathogenesis of Crohn disease and ulcerative colitis.

Effect of glucocorticoid therapy on glucocorticoid receptors in children with autoimmune diseases.

Low-dose glucocorticoids (GC) achieve their action completely by classical genomic effects, mediated by the glucocorticoid receptor (GCR). In high doses of GC, nongenomic effects have also been found, but it is still unclear to what extent they contribute to a beneficial outcome. In this study, we present a determination of the number of lymphocyte GCR sites and the binding affinity in healthy children and children with autoimmune diseases. We further assess the effect of GC administration, especially of high-dose pulse therapy on the number of binding sites. The number of GCR sites per cell was analyzed with [(3)H]-dexamethasone radioligand binding assay and binding affinity (Kd given in nM) in peripheral blood mononuclear cells isolated from 48 healthy children and 35 patients. The patients were divided into three groups based on GC treatment: 0 mg/kg (group 1), 0.01-0.3 mg/kg orally (group 2), and 10-15 mg/kg i.v. pulse therapy (group 3) of prednisolone equivalent per day. Gender- and age-independent normal values of 4338 +/- 1687 sites/lymphocytes and Kd 6.7 +/- 2.2 nM were found. At 3463 +/- 1574, the number of receptor sites in patients without GC (group 1) was significantly lower than that of healthy volunteers (p < 0.05). In patients receiving GC treatment, this value was reduced to 2952 +/- 512 (group 2). Significant down-regulation to a minimum of 479 +/- 168 (group 3) was found after pulse therapy compared with untreated patients (p < 0.01). In pulse therapy, GC lead to a fast and dramatic receptor down-regulation. We suppose that the increase in therapeutic success of pulse-therapy may partly be mediated through additional nongenomic effects.

Higher expression of glucocorticoid receptor in peripheral mononuclear cells in inflammatory bowel disease.

OBJECTIVE: Glucocorticoids are widely used in the treatment of inflammatory bowel disease (IBD). Up- and down-regulated expression of glucocorticoid receptors (GR) has been reported for different chronic inflammatory diseases. The aim of this study was to investigate the expression of GR and their apparent dissociation constant (Kd) in patients with IBD. METHODS: Thirty-nine patients with IBD (22 with ulcerative colitis, 17 with Crohn's disease) and 35 normal controls were studied. Twenty-five patients did not receive steroids, 14 patients were treated with steroids. Peripheral blood mononuclear cells from patients and controls were isolated using the Ficoll-Hypaque gradient and a whole cell [3H]-dexamethasone binding assay and Scatchard plot analysis were performed to assess GR number and the apparent dissociation constant. Results were expressed as mean +/- standard deviation. RESULTS: Normal controls showed an expression of 3,969 +/- 1,555 GR per cell with an apparent dissociation constant of 6.16 +/- 3.8 nmol/L. IBD patients without steroids had a significant increase both in the expression of GR per cell (6,401 +/- 2,344; p < 0.0001; Wilcoxon-Mann-Whitney test) and in the apparent dissociation constant (11.02 +/- 7.57 nmol/L; p = 0.006). Expression of GR in IBD patients was suppressed to normal levels under steroid treatment (4,594 +/- 2,237; p = 0.024), but Kd remained elevated (13.56 +/- 9.05 nmol/L). Plasma cortisol levels were not different between IBD patients and the control group. CONCLUSIONS: Our data show a systemic increase in GR expression and a decrease in the affinity to the GR in IBD, in contrast to other inflammatory diseases such as rheumatoid arthritis and asthma. These changes point towards a systemic character of IBD, which might be considered in a decision between topical and systemic treatment.

Glucocorticoid dose dependent downregulation of glucocorticoid receptors in patients with rheumatic diseases.

OBJECTIVE: The therapeutic success of low doses of glucocorticoids is mediated entirely by classical genomic effects, whereas that of high doses is also mediated to an as yet unknown extent by nongenomic effects. We assessed the relative therapeutic importance of these nongenomic effects in pulse therapy. METHODS: A [3H]dexamethasone radioligand binding assay was used to measure the number of glucocorticoid receptor sites (R, given as number of sites per cell) and glucocorticoid receptor binding affinity (Kd, given in nM) in peripheral blood mononuclear cells isolated from 26 healthy control blood donors and 27 patients with rheumatic diseases. Patients were divided into 4 groups on the basis of their glucocorticoid dose: 0 mg (Group A), < or = 0.25 mg (Group B), 0.25 to 1 mg (Group C), and > 1 mg (Group D) of prednisolone equivalent per kg per day. RESULTS: Sex independent normal values of 3605 +/- 1136 for R and 5.39 +/- 3.4 for Kd were found. At 5407 +/- 1968, the number of receptor sites in patients not receiving glucocorticoid therapy (Group A) was significantly higher than that of controls (p < 0.01). In patients receiving glucocorticoid therapy this value was reduced at 3855 +/- 866 (Group B), 3358 +/- 963 (Group C), and 2685 +/- 962 (Group D). The values in Groups C and D were significantly lower than those in untreated patients (p < 0.02). CONCLUSION: In pulse therapy doses of glucocorticoids that exceed receptor saturation are administered for several days, but in addition significant receptor downregulation occurs. Therefore, we assume an increase in the relative contribution of the nongenomic effects of glucocorticoids to the therapeutic success under these conditions.