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Subtle histopathologic features such as eosinophilia and increased mast cells have been observed in functional gastrointestinal disorders (FGIDs), including functional dyspepsia (FD) and the irritable bowel syndrome (IBS). The mechanisms that drive recruitment of these cells to the gastrointestinal tract remain unexplained, largely due to the heterogeneity in phenotypes among patients diagnosed with such conditions. We aimed to systematically review the literature and collate the evidence for immune activation in FD and IBS, and where possible, detail the nature of activation.Seven literature databases were searched using the keywords: 'functional gastrointestinal disorder', FGID, 'functional dyspepsia', 'non-ulcer dyspepsia', 'idiopathic dyspepsia', 'irritable bowel syndrome', IBS and 'immun*'.Fifty-one papers reporting discordant immune features met the selection criteria for this review. Changes in lymphocyte populations, including B and T lymphocyte numbers and activation status were reported in IBS and FD, in conjunction with duodenal eosinophilia in FD and increased colonic mast cells in IBS. Increases in circulating α4+β7+ gut-homing T cells appear to be linked to the pathophysiology of both FD and IBS. Studies in the area are complicated by poor phenotyping of patients into subgroups and the subtle nature of the immune activity involved in FD and IBS.Alterations in proportions of gut-homing T lymphocytes in both FD and IBS indicate that a loss of mucosal homeostasis may drive the symptoms of FD and IBS. There is indirect evidence that Th17 responses may play a role in FGIDs, however the evidence for a Th2 immune phenotype in FD and IBS is limited. Although immune involvement is evident, large, well-characterised patient cohorts are required to elucidate the immune mechanisms driving the development of FGIDs.

© 2018 Wolters Kluwer Health, Inc. All rights reserved. BACKGROUND Cell-free mitochondrial DNA (mtDNA) is proinflammatory and has been detected in high concentrations in trauma patients' plasma. Deoxyribonuclease (DNAse) is the free plasma enzyme responsible for the digestion of extracellular DNA. The relationship between mtDNA and DNAse after major trauma is unknown. We hypothesized that DNAse activity would be elevated after injury and trauma surgery and would be associated with high concentrations of extracellular DNA. METHODS Two-year prospective study was performed on 103 consecutive trauma patients (male, 81%; age, 38 years [interquartile range, 30-59 years]; injury severity score, 18 [interquartile range, 12-26 years]) who underwent standardized major orthopedic trauma surgical interventions. Blood was collected at five perioperative time points (preoperative, postoperative, 7 hours, 24 hours, and 3 days postoperatively). Healthy control subjects (n = 20) were also sampled. Cell-free mtDNA and nuclear DNA (nDNA) were measured using quantitative polymerase chain reaction. Deoxyribonuclease was also assayed in the same plasma samples. RESULTS Increased levels of mtDNA (from preoperative 163 ± 86 ng/mL to 3 days 282 ± 201 ng/mL, p < 0.0001) and nDNA (from preoperative 28 ± 20 ng/mL to 3 days 37 ± 27 ng/mL, p < 0.05) were present in trauma patients at all perioperative time points compared with healthy controls (mtDNA: 4 ± 2 ng/mL; nDNA: 10 ± 5 ng/mL). Deoxyribonuclease activity was lower in the trauma cohort (from preoperative 0.06 ± 0.04U/mL to 3 days 0.08 ± 0.04U/mL, p < 0.0001) compared with healthy controls (DNAse: 0.17 ± 0.03U/mL). There was no correlation between DNAse and perioperative DNA concentrations. Elevated mtDNA (but not nDNA) correlated with the development of systemic inflammatory response syndrome (SIRS) (p = 0.026) but not multiple organ failure. CONCLUSIONS The significant perioperative elevation in plasma-free mtDNA concentration is associated with the development of SIRS. The fact that increased cell-free DNA concentrations present with significantly lower than healthy control DNAse activity suggests a potential therapeutic opportunity with DNAse administration to modulate postinjury severe SIRS. LEVEL OF EVIDENCE Prognostic/Epidemiological, level II.

Genetics, Mucosal Inflammation, and the Environment in Post-Infectious Chronic Gut Syndromes

OBJECTIVES: Anti-cytolethal distending toxin B (CdtB) and anti-vinculin antibodies have been proposed as biomarkers that discriminate irritable bowel syndrome (IBS) diarrhea from inflammatory bowel disease; however, it is unknown whether they can also discriminate patients with IBS and IBS subtypes and functional dyspepsia (FD) from healthy individuals in the general population. We aimed to determine whether anti-CdtB and anti-vinculin can discriminate IBS and FD from health and from organic gastrointestinal (GI) disease. METHODS: Adults were enrolled from 2 Australian studies: (i) a random, population-based study (n = 331) with subjects diagnosed with IBS (n = 63) or FD (n = 61) by modified Rome III criteria or healthy control subjects (n = 246) who did not meet criteria for IBS and/or FD and (ii) an outpatient-based study with subjects diagnosed with IBS (n = 256) and/or FD (n = 55) or organic GI disease (n = 182) by an independent clinician. Serum levels of anti-CdtB/anti-vinculin antibodies were determined by enzyme-linked immunosorbent assay. RESULTS: There was a significantly higher mean value of anti-CdtB in FD vs healthy controls (mean = 2.46 [SD = 0.72] vs mean = 2.14 [SD = 0.77]; P = 0.005) and IBS/FD overlap vs healthy controls (mean = 2.47 [SD = 0.78] vs mean = 2.14 [SD = 0.77]; P = 0.02). There were no significant differences in anti-CdtB in IBS and FD outpatients or IBS/FD subgroups compared with patients with organic GI disease. In terms of anti-vinculin, there were no significant differences between IBS and FD and healthy controls or between IBS and FD and organic GI disease controls. DISCUSSION: We did not confirm that anti-CdtB/anti-vinculin discriminated IBS diarrhea from organic GI disease in Australian subjects. However, we did find higher anti-CdtB in FD and IBS/FD overlap vs healthy controls. Postinfectious FD may be more common than currently recognized.