MyD88-mediated signaling prevents development of adenocarcinomas of the colon: role of interleukin 18.

Signaling through the adaptor protein myeloid differentiation factor 88 (MyD88) promotes carcinogenesis in several cancer models. In contrast, MyD88 signaling has a protective role in the development of azoxymethane (AOM)/dextran sodium sulfate (DSS) colitis-associated cancer (CAC). The inability of Myd88(-/-) mice to heal ulcers generated upon injury creates an altered inflammatory environment that induces early alterations in expression of genes encoding proinflammatory factors, as well as pathways regulating cell proliferation, apoptosis, and DNA repair, resulting in a dramatic increase in adenoma formation and progression to infiltrating adenocarcinomas with frequent clonal mutations in the beta-catenin gene. Others have reported that toll-like receptor (Tlr) 4-deficient mice have a similar susceptibility to colitis to Myd88-deficient mice but, unlike the latter, are resistant to CAC. We have observed that mice deficient for Tlr2 or Il1r do not show a differential susceptibility to colitis or CAC. However, upon AOM/DSS treatment Il18(-/-) and Il18r1(-/-) mice were more susceptible to colitis and polyp formation than wild-type mice, suggesting that the phenotype of Myd88(-/-) mice is, in part, a result of their inability to signal through the IL-18 receptor. This study revealed a previously unknown level of complexity surrounding MyD88 activities downstream of different receptors that impact tissue homeostasis and carcinogenesis.

RAGE gene polymorphisms in patients with multiple sclerosis.

The pathogenesis of multiple sclerosis (MS), a devastating neuroinflammatory disorder of the central nervous system, has been presumed to involve the possible importance of the receptor for advanced glycation end products (RAGE). The aim of this study was to investigate the relevance of the genetic polymorphisms of RAGE in MS patients. A total of 168 patients with MS were enrolled; 136 healthy blood donors served as controls. The -374 T/ A, -479 T/C, and the G82S polymorphisms of RAGE were determined by restriction fragment length polymorphism (RFLP). There was a significant difference in RAGE -374 T/A genotype distribution between the controls and the MS patients. The AA homozygote variants were detected in 8% of the patients with MS, as compared with 19% of healthy controls (OR=2.75; 95% CI=1.319-5.733, p = 0.007). No differences were observed between the MS patients and the controls, concerning the frequencies of the -479 T/C and G82S genotypes of the RAGE. Our results revealed an association between the -374 T/A polymorphism of the RAGE promoter and MS. The genetic variant -374 AA (which has previously been shown to exert significant effects on transcriptional activity) can be considered a preventive factor as regards the occurrence of MS. Our findings support the view that RAGE plays a role in the development of MS.

Polymorphisms of the ApoE, HSD3B1, IL-1beta and p53 genes are associated with the development of early uremic complications in diabetic patients: results of a DNA resequencing array study.

Genetic polymorphisms of the genes involved in angiogenesis, the inflammatory cascade or apoptosis control can influence the chronic complications of diabetic patients. Parallel evaluation of multiple genetic polymorphisms became available with the development of DNA resequencing arrays. We aimed to develop a 16-gene, 18,859-nucleotide resequencing array to analyze the genetic background of uremic and gastrointestinal complications. DNA was isolated from 10 ml of peripheral blood of 41 non-uremic and 37 uremic patients with type II diabetes mellitus (DM); 32 suffering from gastric erosion complications. An Affymetrix Customseq Resequencing array was developed containing a total of 37 PCR products of selected genes. Confirmatory analysis was performed for 5 known polymorphisms by RFLP and for 4 others by capillary sequencing. Statistical analysis was performed using the Fisher's exact test. Correlations between the DNA resequencing array and the confirmatory methods were 96% for RFLP and 99.4% for capillary sequencing. The genetic polymorphisms of the ApoE, HSD3B1, IL-1beta and p53 genes were found to be significantly different (p<0.05) between the uremic and non-uremic diabetes group. In regards to the gastric erosion complications of the diabetic uremic patients, the A17708T polymorphism of the p53 intron 10 was found to have a statistically significant (p<0.05) role. In conclusion, DNA sequencing arrays can contribute to a multiparameter genetic analysis yielding highly correlating results using a single method in patients suffering type II DM.

T-251A polymorphism of IL-8 relating to the development of histological gastritis and G-308A polymorphism of TNF-alpha relating to the development of macroscopic erosion.

OBJECTIVES: Genetic variations of the inflammatory IL-8 and TNF-alpha genes can influence the outcome of gastric alterations. Our aims were to determine the prevalence and effect of the T-251A functional polymorphism of IL-8 and the G-308A polymorphism of TNF-alpha in histological and macroscopic gastric diseases related to Helicobacter pylori infection. METHODS: Genomic DNA was extracted from biopsy samples from patients with gastritis (n=86, H. pylori positive=41), atrophy (n=32, H. pylori positive=13), intestinal metaplasia (IM) (n=43, H. pylori positive=22) and from histologically negative patients (n=57). The samples were divided by macroscopic diagnosis into erosion and negative groups. The T-251A polymorphism was examined with the amplification refractory mutation system method; the G-308A polymorphism was determined by the polymerase chain reaction-restriction fragment length polymorphism method. For statistical evaluation, Fischer's exact test was used. RESULTS: In the case of T-251A of IL-8, the frequency of the A/A genotype was significantly increased in gastritis (P=0.049) and IM (P=0.038) groups as compared with the histologically negative ones. No relationship was found between macroscopic erosions and H. pylori infection. In the case of G-308A, the G/G genotype frequency was statistically increased in erosions as compared with negative groups (P=0.035). No difference in the distribution of G-308A genotypes in relation to histological alterations and the H. pylori infection was observed. CONCLUSIONS: The effect of the polymorphism of IL-8 seems to be relevant in the pathogenesis of histological gastritis and IM, and the effect of the polymorphism of TNF-alpha is relevant in the pathogenesis of macroscopic erosive gastritis.

Chronic infections and genetic factors in the development of ischemic stroke.

The aim of this study was to examine whether chronic infections and genetic factors of the host play roles in the pathophysiology of acute noncardioembolic ischemic stroke. Blood samples from 59 subjects with ischemic stroke and 52 control patients were investigated by nested PCR for the presence of C. pneumoniae DNA, HCMV DNA and enterovirus RNA, by ELISA for the levels of antibodies to C. pneumoniae, HCMV, HSV, HHV-6, EBV and the inflammatory chemokine IL-8, and by PCR for promoter polymorphism of the IL-8 and CD14 host genes. Associations of stroke with the HCMV IgG and HSV-1 IgA antibody levels were observed. No association of stroke was detected with the presence of C. pneumoniae, HCMV or enterovirus nucleic acids in the peripheral blood, C. pneumoniae IgM, IgG and IgA, the HSV IgG, the EBV IgG, or HHV-6 IgG antibody levels, the pathogen burden, the IL-8 or CD14 promoter polymorphisms, or with the serum levels of IL-8 in the overall study population. These results are consistent with the hypothesis that certain pathogens are involved in the development of ischemic stroke.

The risk of early and late lung sequelae after conformal radiotherapy in breast cancer patients.

PURPOSE: To study the risks of early and late radiogenic lung damage in breast cancer patients after conformal radiotherapy. METHODS AND MATERIALS: Radiogenic lung sequelae were assessed prospectively in 119 patients by means of clinical signs, radiologic abnormalities, and the mean density change (MDC) of the irradiated lung on CT. RESULTS: Significant positive associations were detected between the development of lung abnormalities 3 months or 1 year after the radiotherapy and the age of the patient, the ipsilateral mean lung dose (MLD), the radiation dose to 25% of the ipsilateral lung (D(25%)) and the volume of the ipsilateral lung receiving 20 Gy (V(20 Gy)). The irradiation of the axillary and supraclavicular lymph nodes favored the development of pneumonitis but not that of fibrosis. No relation was found between the preradiotherapy plasma TGF-beta level and the presence of radiogenic lung damage. At both time points, MDC was strongly related to age. Significant positive associations were demonstrated between the risks of pneumonitis or fibrosis and the age of the patient, MLD, D(25%), and V(20 Gy). A synergistic effect of MLD, D(25%), and V(20 Gy) with age in patients older than 59 years is suggested. CONCLUSION: Our analyses indicate that the risks of early and late radiogenic lung sequelae are strongly related to the age of the patient, the volume of the irradiated lung, and the dose to it.

Genetic polymorphisms of NOD1 and IL-8, but not polymorphisms of TLR4 genes, are associated with Helicobacter pylori-induced duodenal ulcer and gastritis.

BACKGROUND: Intracellular pathogen receptor NOD1 is involved in the epithelial cell sensing Helicobacter pylori, which results in a considerable interleukin (IL)-8 production. The aim of this study was to evaluate the relationship between NOD1 and IL-8 genetic polymorphisms and the development of H. pylori-induced gastritis and duodenal ulcer (DU), as compared with TLR4 polymorphisms. MATERIALS AND METHODS: Eighty-five patients with DU and 135 patients with gastritis were enrolled in the study. Seventy-five serologically H. pylori-positive subjects without gastric or duodenal symptoms served as controls. The G796A (E266K) NOD1 polymorphism was determined by restriction fragment length polymorphism, and the -251 IL-8 polymorphism by amplification refractory mutation system method. The TLR4 (ASP/299/Gly and Thr/399/Ile) gene polymorphisms were examined by melting point analysis. RESULTS: AA homozygote mutant variants of NOD1 were detected in 20% of the H. pylori-positive patients with DU versus 7% of H. pylori-positive patients with gastritis and versus 6% of the H. pylori-positive healthy controls. The IL-8 heterozygote mutant variant was detected with a significantly higher frequency among the DU patients and those with gastritis than among the H. pylori-positive controls. However, no significant correlation concerning the frequency of the TLR4 gene polymorphism could be revealed between any group of patients and the controls. CONCLUSION: E266K CARD4/NOD1, but not the TLR4 gene polymorphism increases the risk of peptic ulceration in H. pylori-positive patients. The -251 IL-8 polymorphism was significantly associated with either gastritis or DU in H. pylori-infected subjects. Host factors including intracellular pathogen receptors and IL-8 production play an important role in H. pylori-induced gastric mucosal damage.

High mobility group box 1 protein induction by Mycobacterium bovis BCG.

UNLABELLED: High mobility group box 1 protein (HMGB1), a nuclear protein, is a critical cytokine that mediates the response to infection, injury, and inflammation. The aim of our study was to elaborate a reliable in vitro model to investigate whether Mycobacterium bovis BCG is able to induce HMGB1 secretion from the monocytic U-937 cells. Western blot technique was applied for the detection of HMGB1 from supernatants of cells, following induction with Mycobacterium bovis BCG. Densitometric analysis revealed higher concentrations of HMGB1 in cell supernatants stimulated with BCG than in the supernatants of the control, nonstimulated cells. Further quantitation of the secreted HMGB1 was performed by ELISA. The BCG strain resulted in a higher amount of secreted HMGB1 (450 +/- 44 ng/mL) than that of LPS (84 +/- 12 ng/mL) or Staphylococcus aureus (150 +/- 14 ng/mL). BCG and Phorbol -12-myristate -13 acetate (PMA), added together, resulted in the highest HMGB1 secretion (645 +/- 125 ng/mL). The translocation of the HMGB1 towards the cytoplasm following infection of cells with BCG was demonstrated by immunofluorescence examinations. CONCLUSION: Our pilot experiments draw attention to the HMGB1 inducing ability of Mycobacterium bovis. Assesment of the pathophysiological role of this late cytokine in mycobacterial infections demands further in vitro and in vivo examinations.

Polymorphism of the heat-shock protein gene Hsp70-2, but not polymorphisms of the IL-10 and CD14 genes, is associated with the outcome of Crohn's disease.

OBJECTIVE: In Crohn's disease (CD) a Th-1 dominant immune reaction is induced, which could be associated with genetic predisposition. Several previous studies have investigated the roles of CD14, heat-shock protein (Hsp)70 and IL-10 gene polymorphisms in the development of the disease. The results are contradictory and inter-racial differences are implicated. Therefore, this phenomenon was evaluated in well-documented Caucasian patients with CD in order to verify the clinical importance of these polymorphisms. MATERIAL AND METHODS: The genomic DNA of 133 patients with CD and that of 75 healthy controls were examined. CD was divided into subgroups according to the Vienna classification. An arbitrary classification system based on disease severity was also applied, which was determined according to the therapeutic intervention. The CD14 (-159 C-->T) promoter gene polymorphism was investigated by melting-point analysis. The IL-10 (-1082 G-->A) and Hsp70-2 (1267 A-->G) gene polymorphisms were detected by RFLP (restriction fragment length polymorphism). RESULTS: None of the allele frequencies of the examined polymorphisms differed significantly between the patient and control populations. Neither the CD14 nor the IL-10 polymorphisms exhibited any correlation with the development or with the progression of the disease. With regard to Hsp70-2 gene polymorphism, those patients who carry at least one A allele have a significantly lower probability of the need for surgical intervention. CONCLUSIONS: Allele A of the Hsp70-2 gene may be associated with a less severe form of CD, suggesting the clinical value of the genotype assessment. The genetic determination of the defense mechanisms in CD appears to be associated with the polymorphism of the Hsp70-2 gene rather than that of the CD14 or IL-10 genes.

Clinical importance of transforming growth factor-beta but not of tumor necrosis factor-alpha gene polymorphisms in patients with the myelodysplastic syndrome belonging to the refractory anemia subtype.

OBJECTIVES: Tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta (TGF-beta) are cytokines that play key roles in the myelodysplastic syndrome (MDS). There have been several reports on the presence of genetic polymorphisms in the DNA sequence encoding the leader sequence of the TGF-beta1 protein, located in codon 10 in exon 1 and in the -308 promoter region of TNF-alpha. The objective of this study was to investigate the association between TNF-alpha and TGF-beta1 gene polymorphisms and the susceptibility to MDS and the progression of the disease among patients with MDS belonging to the refractory anemia (RA) subtype. METHODS: The diagnosis of MDS (n = 50) was based on the FAB criteria. The TNF-alpha genotypes were analyzed by PCR-RFLP and the TGF-beta genotypes were analyzed using an amplification refractory mutation system. RESULTS AND CONCLUSIONS: Compared with healthy control subjects, patients with RA showed no significant deviations in genotype or allele frequencies of TNF-alpha. The TT homozygosity at codon 10 of TGF-beta1 was significantly higher among patients with bi- or pancytopenia (severe group) than in the patients with anemia only (mild group; odds ratio = 6.99, p = 0.003). These findings suggest that the TGF-beta1 gene polymorphism in codon 10 and the -308 TNF-alpha gene polymorphism do not predispose to the development of RA, but the TGF-beta1 gene polymorphism may affect disease progression.

Genetic polymorphisms in patients with myelodysplastic syndrome.

Myelodysplastic syndrome (MDS) is a family of clonal disorders characterized by dyshematopoiesis and susceptibility to acute myelogenous leukemia. Tumor necrosis factor-a (TNF-alpha) and transforming growth factor-beta (TGF-beta) are cytokines that play key roles in the pathogenesis of MDS. There have been several reports on the presence of genetic polymorphisms in the DNA sequence encoding the leader sequence of the TGF-beta protein, and in the -308 promoter region of TNF-alpha. The association between TNF-alpha and TGF-beta1 gene polymorphism and the susceptibility to MDS and the progression of the disease was investigated. As compared with healthy control subjects (n = 74), patients with MDS (n = 55) showed no significant deviations in genotype or allele frequencies of TNF-alpha. Similarly, there were no differences in the distribution of TNF-alpha genotypes between the MDS patients with only anemia (mild group) and those with bi- or pancytopenia (severe group). On the other hand the TT homozygosity at codon 10 in exon 1 of TGF-beta1 gene was associated with a severe degree of cytopenia [95% CI OR = 4.889, p = 0.0071]. These findings suggest that the investigated genetic polymorphisms do not predispose to the development of MDS, but that TGF-beta1 gene polymorphism may affect the disease progression.

Tumour necrosis factor-alpha and heat-shock protein 70-2 gene polymorphisms in a family with rheumatoid arthritis.

OBJECTIVES: The aim of this work was to investigate the prevalence of TNF-alpha-308 polymorphism among the 29 members of a family with RA and the association between the MHC-linked biallelic HSP70-2 gene and the TNF-alpha polymorphism. Five of the members with RA were diagnosed by using the revised 1987 ACR criteria, and 1 member suffered from SLE. METHODS: The variations in the TNF-alpha and the HSP70-2 genotypes were analyzed by PCR-RFLP, using NcoI and PstI restriction enzymes. RESULTS: Two of the 29 members were homozygotes for allele A, 18 were heterozygotes (TNF A/G) and 9 of them were homozygotes for allele G. Nineteen of the 29 were heterozygotes for HSP70-2 (A/G), 10 of them were homozygotes for the G allele, and none were homozygotes for allele A. Four of the 5 the RA patients carried the A allele for TNF-alpha all 5 were heterozygotes for HSP70-2 genotypes. CONCLUSION: The carriage of the A allele for TNF-alpha of -308 SNP in 4 of the 5 RA patients, and the high prevalence (68.0%) of TNF A allele carriers in this family confirms the important role of this candidate gene in the pathomechanism of RA, and might be of prognostic value for future clinical observations. Further, to test for association a much larger set of genetically independent patients and controls is needed.

Helicobacter pylori-induced immunological responses in patients with duodenal ulcer and in patients with cardiomyopathies.

The interaction between the bacteria and the host is a key factor determining the clinical consequences of H. pylori infection. The immune system plays an important role in either promoting or preventing the disease. The mucosal production of TNF-alpha, IL-6, IL-8 and IL-10 and the CagA status were investigated in H. pylori-positive patients with duodenal ulcer (DU). The concentrations of these cytokines in gastric antral mucosal specimens from patients infected with H. pylori (n = 40) were determined by ELISA and compared with data on mucosal specimens from H. pylori-negative patients (n = 12). The local TNF-alpha, IL-6 and IL-8 concentrations in the antral biopsy samples were significantly higher (p < 0.001) in the patients infected with H. pylori than in the samples from the H. pylori-negative subjects. CagA positivity was demonstrated in 39 (97.5%) of the 40 patients with DU, and in 41 (70.7%) of H. pylori-positive (58 of 100) healthy blood donors. In complementary studies focusing on extragastric disease, it was found that 57% of patients with ischaemic heart disease were seropositive as concerns H. pylori, and 91% of them had antibodies against human heat shock protein 60, too. This study suggests that, besides the bacterial virulence factor, the host response of an increased mucosal production of inflammatory cytokines can be relevant to the gastric pathophysiology in H. pylori-induced DU. At the same time, in ischaemic heart diseases the role of autoimmune processes induced by H. pylori cannot be excluded.

Investigation of the prognostic value of TNF-alpha gene polymorphism among patients treated with infliximab, and the effects of infliximab therapy on TNF-alpha production and apoptosis.

OBJECTIVES: Infliximab, a chimeric anti-tumor necrosis factor (TNF) antibody, is highly effective for the treatment of Crohn's disease (CD) and rheumatoid arthritis (RA). Our experiments focused on RA and CD patients receiving infliximab. Since cytokine production is largely determined by genetic factors, the promoter polymorphisms of TNF-alpha were examined among these patients. Additionally, the changes caused by infliximab in the TNF-alpha-producing ability and apoptosis of peripheral blood mononuclear cells (PBMCs) were investigated. METHODS: The TNF-alpha genotypes were analyzed by PCR-RFLP. The in vitro TNF-alpha production of the PBMCs was detected by flow cytometric analysis. The TNF-alpha concentration in the supernatant was measured by bioassay. Apoptosis was detected by annexin V-fluorescein isothiocyanate labeling. RESULTS AND CONCLUSIONS: 8 of the 12 nonresponder patients carried the TNF A allele associated with high TNF-alpha production. We suggest that the determination of TNF polymorphism may help identify more suitable candidates for infliximab treatment. Although in vitro infliximab treatment for 48 h resulted in significant (44.2 +/- 1.17%) apoptosis in PBMCs, in ex vivo samples from RA patients who received infliximab, apoptosis was only 13.3 +/- 1.6%. Furthermore, infliximab did not result in irreversible inhibition of the TNF-alpha-producing ability or in the significant apoptosis of PBMCs.

Effects of Helicobacter pylori infection on gastric inflammation and local cytokine production in histamine-deficient (histidine decarboxylase knock-out) mice.

UNLABELLED: Helicobacter pylori infection in humans causes gastritis. The infection elicits a complex immune response in which the activation of mast cells and histamine release is of particular importance. Histamine further promotes the immune response and stimulates gastric acid secretion. The inflammatory effects of H. pylori can be studied in intragastrically infected mice. The aim of this study was to compare the local cytokine responses of histamine-deficient, histidine decarboxylase knock-out (HDC KO) and wild-type (WT) mice following H. pylori infection. METHODS: H. pylori was administered intragastrically to HDC KO and WT mice. The animals were infected three times in a 1-week-period and were sacrificed 8 weeks after the first intervention. The local TNF-alpha, IL-6 and IL-10 cytokine levels in gastric mucosal specimens were determined by ELISA. Gastric mucosa sections were also analysed for histological signs of inflammation. To investigate the antibody response following H. pylori infection, the total anti-H. pylori IgG and the ratio of IgG1/IgG2a isotypes were determined in the serum by ELISA. RESULTS: H. pylori induced considerable cytokine production in the infected groups. The TNF-alpha and IL-6 levels were significantly higher in the WT mice than in the HDC KO mice, whereas the IL-10 levels did not differ between the groups. Anti-H. pylori IgG was detected only in the infected groups and the titre was higher in the WT mice. A higher IgG1/IgG2a ratio was observed in the H. pylori infected HDC KO group. Histological analysis revealed that the grades of inflammation were less severe in the infected HDC KO animals. CONCLUSIONS: The results suggest that H. pylori induces lower TNF-alpha and IL-6 secretion in the gastric mucosa in the HDC KO mice than in the WT animals, while the levels of induction of IL-10 were similar. The imbalance between Th1/Th2 is less pronounced in the HDC KO mice, which might explain the milder inflammation in the gastric mucosa. These results provide further information on the role of histamine in the pathomechanism of H. pylori-induced gastritis.

Genetic polymorphism of interleukin-8 (IL-8) is associated with Helicobacter pylori-induced duodenal ulcer.

BACKGROUND AND AIMS: Helicobacter pylori infection almost invariably causes chronic gastritis, but only a proportion of the infected subjects develop peptic ulcers. The local inflammation associated with H. pylori infection is characterized by an increased production of the proinflammatory cytokines IL-1-B, IL-6, IL-8 and TNF-alpha. Since such cytokine production is often determined by the genetic polymorphism of regions regulating cytokine gene expression, we investigated the relationship between TNF-alpha and IL-8 polymorphisms and the development of duodenal ulcer disease. We also sought a correlation between the promoter polymorphism of the lipopolysaccharide (LPS) receptor CD14 and the formation of peptic ulcer, because CD14 plays a crucial role in the initiation of the cytokine cascade. METHODS: Genomic DNA extracted from the peripheral blood of 69 patients with H. pylori-positive duodenal ulcer disease and 47 H. pylori-positive healthy controls was analyzed for TNF-alpha -308 promoter polymorphism by RFLP, and for IL-8 -251 polymorphism by ARMS. Genetic polymorphism within the promoter of the CD14 gene was identified using the LightCycler instrument via melting point analysis. RESULTS: No significant correlation could be revealed between the TNF-alpha and CD14 promoter polymorphisms and the clinical outcome of H. pylori infection. The IL-8 A/T heterozygote mutant variant was detected with a significantly higher frequency (65.22%) among the ulcer patients than among the healthy, H. pylori-positive blood donors (36.17%), while the frequency of the normal allelic genotype (TT) was significantly higher in the control group (44.6% vs 15.9%). CONCLUSION: Analysis of the genetic predisposition to enhanced cytokine production revealed a significant association only for the IL-8 polymorphism. This observation draws attention to the possible importance of IL-8 polymorphism as a genetic predisposing factor in the pathomechanism of H. pylori-induced duodenal ulcer disease, and to the relative protection from duodenal ulcer disease that is associated with the TT genotype.

Local and peripheral cytokine response and CagA status of Helicobacter pylori-positive patients with duodenal ulcer.

The mucosal production of TNF-alpha, IL-6, IL-8, IL-10 and nitrotyrosine was investigated in H. pylori-positive patients with duodenal ulcer (DU). The concentrations of these cytokines in gastric antrum mucosal specimens from patients infected with H. pylori (n = 40) were determined by ELISA and compared with data on mucosal specimens from H. pylori-negative patients (n = 12). Nitrotyrosine was determined by ECL Western blotting. It was additionally investigated whether the tissue levels of the cytokines correlated with the peripheral cytokine levels, and the CagA status of the patients. The local TNF-a, IL-6 and IL-8 concentrations in the antral biopsy samples were significantly higher (p < 0.001) in the patients infected with H. pylori than in the samples from the H. pylori-negative subjects. There was a negative correlation between the TNF-alpha and IL-10 concentrations. Further more, in 23 of the 40 biopsy specimens, considerable nitrotyrosine production was detected by ECL Western blotting. There was no significant difference in peripheral TNF-a and IL-6 production between the DU patients and healthy blood donors (n = 100; 58% of whom were also H. pylori-positive). Only the in vitro IL-8-producing capacity was higher in the peripheral blood of the DU group after ex vivo induction with H. pylori. CagA positivity was demonstrated in 39 (97.5%) of the 40 patients with DU, and in 41 (70.7%) of the 58 H. pylori-positive, healthy blood donors. This study suggests that besides the bacterial virulence factor, the host response, with an increased mucosal production of inflammatory cytokines and reactive oxygen and nitrogen species could be relevant to the gastric pathophysiology in H. pylori-induced DU. There is no generalized cytokine overproduction in these DU patients, but the moderate increase in in vitro IL-8 production might be of pathophysiological importance.