Marian C. Aldhous

Anti-Saccharomyces cerevisiae antibodies (ASCA) in Crohn's disease are associated with disease severity but not NOD2/CARD15 mutations

Anti‐Saccharomyces cerevisiae antibodies (ASCAs) have been proposed as serological markers, which may differentiate Crohns disease (CD) from ulcerative colitis (UC) and predict disease phenotype. Their importance in pathogenesis is unproven. We investigated the relationship between ASCAs, disease phenotype and NOD2/CARD15 genotype in CD and whether ASCAs were related to antibodies to other fungal proteins. Serum from 228 patients [143 CD, 75 UC, 10 with indeterminate colitis (IC)] and 78 healthy controls (HC) were assayed for ASCA. Antibodies (IgA, IgG) to other fungal proteins (Fusarium species ATC20334, Mycoprotein) were measured in the same samples using an in‐house enzyme‐linked immunosorbent assay (ELISA) assay. ASCAs were present in 57% of CD, 19% of UC, 30% of IC and 8% of HCs. ASCA‐positive status was a predictor for CD with sensitivity of 57%, specificity of 87%, positive predictive value of 78% and negative predictive value of 68%. ASCA was associated with proximal (gastroduodenal and small bowel involvement) rather than purely colonic disease (P < 0·001) and with a more severe disease phenotype and requirement for surgery over a median follow‐up time of 9 years (P < 0·0001). No associations with NOD2/CARD15 mutations were seen. There was no association between ASCA and antibodies to MP (IgA or IgG). These data implicate ASCA as a specific marker of disease location and progression in CD, emphasizing the heterogeneity within IBD.

Does cigarette smoking influence the phenotype of Crohn's disease? Analysis using the Montreal classification.

OBJECTIVES:The clinical subclassification of Crohns disease by phenotype has recently been reevaluated. We have investigated the relationships between smoking habit, age at diagnosis, disease location, and progression to stricturing or penetrating complications using the Montreal classification.METHODS:408 patients (157 male, median age 29.4 yr) were assessed. Data were collected on smoking habit, age at diagnosis, anatomical distribution, and disease behavior. Follow-up data were available on all patients (median 10 yr).RESULTS:At diagnosis, ex-smokers (N = 53) were older than nonsmokers (N = 177) or current smokers (N = 178, medians 43.2 vs 28.3 or 28.9 yr, respectively, P < 0.001). Disease location differed according to smoking habit at diagnosis (χ2 = 24.1, P = 0.02) as current smokers had less colonic (L2) disease than nonsmokers or ex-smokers (30% vs 45%, 50%, respectively). In univariate Kaplan–Meier survival analysis, smoking habit at diagnosis was not associated with time to development of stricturing disease, internal penetrating disease, perianal penetrating disease, or time to first surgery. Patients with isolated colonic (L2) disease were slower to develop strictures (P < 0.001) or internal penetrating disease (P = 0.001) and to require surgery (P < 0.001). Cox models with smoking habit as time-dependent covariates showed that, relative to ileal (L1) location of disease, progression to stricturing disease was less rapid for patients with colonic (L2) disease (HR 0.140, P < 0.001), but not independently affected by smoking habit. Progression to surgery was also slower for colonic (L2) than ileal (L1) disease location (HR 0.273, P < 0.001), but was independent of smoking habit.CONCLUSIONS:Smoking habit was associated with age at diagnosis and disease location in Crohns disease, while disease location was associated with the rate of development of stricturing complications and requirement for surgery. The pathogenic basis of these observations needs to be explained.

Smoking Habit and Load Influence Age at Diagnosis and Disease Extent in Ulcerative Colitis

INTRODUCTION:Cigarette smoking affects susceptibility to ulcerative colitis (UC), but its effects on age at diagnosis, disease extent, and need for surgery are less well defined. We examined these parameters in a detailed retrospective analysis of a large cohort of well-characterized UC patients.METHODS:499 UC patients (254 male, median age 34.3 yr) were studied. Data were collected on smoking habits, smoking load (pack-years), age at recruitment, age at diagnosis, surgery, and disease extent. Colonoscopic and histological data at both diagnosis and follow-up (median follow-up time 4.6 yr) were available on 349 patients.RESULTS:Ex-smokers were older at diagnosis than current or nonsmokers, (46.5 yr vs 31.1 or 29.4 yr, respectively, P < 0.001). Before diagnosis, ex-smokers had a higher smoking load than current smokers (13.0 vs 6.94 pack-years, P < 0.001). A Cox model for age at diagnosis, with smoking as a time-dependent covariate, showed that at any age, ex-smokers were significantly more likely to develop UC than current smokers (hazard ratio 1.8, 95% CI 1.41–2.44, P < 0.001). For current smokers at latest colonoscopy, those with extensive disease were the lightest smokers (median 0.320 pack-years), whereas those with healthy colons were the heaviest smokers (median 9.18 pack-years, P = 0.006). At 5 yr, regression of extensive disease was more frequent in current than ex-smokers or nonsmokers (30% current smokers vs 8% nonsmokers and 5% ex-smokers, χ2 = 30.4, P < 0.001) but these differences were not maintained over a longer time period.CONCLUSIONS:Smoking habit influences the age at diagnosis and changes in disease extent in UC. Mechanisms are likely to be complex and require further investigation.

Cytotoxic T lymphocyte activity and CD8 subpopulations in children at risk of HIV infection

HIV‐specific cytotoxic T lymphocytes (CTL) are thought to play a major role in viral control in HIV‐infected adults. Changes in the relative proportions of CD8 lymphocyte subpopulations are also thought to be associated with disease progression. Less is known about the relative effectiveness of CTL against different HIV targets, or about the relationship, if any, between CTL activity and CD8 subpopulations. We have measured CTL activity against four HIV gene products (gag, tat, pol and env) and expression of CD45RO, CD45RA, HLA‐DR, CD29, S6F1, and CD57 surface markers on CD8 cells from nine HIV‐infected and 11 HIV‐uninfected children. Of nine HIV‐infected children, six showed antigen‐specific CTL activity on at least one occasion: 4/6 directed against tat, 6/6 against pol, 1/6 against env, and 1/6 against gag. However, the specificity of the CTL activity varied between children and within individual children with time. Furthermore, two uninfected children showed CTL activity, one to HIV‐gag,‐pol and ‐tat, and the other to HW‐pol. All the HIV‐infected and two uninfected children had abnormal proportions of CD8 subpopulations in whole blood compared with age‐matched controls. There was no correlation between CTL activity and CD8 subsets in whole blood. Five children changed from CTL‐positive to CTL‐negative (or vice versa) during the study. In these, the occasions when CTL activity was detected coincided with an increase in CD8 cells, an expansion of HLA‐DR+ CD8 cells and a loss of CD45RA+ CD8 cells.

NOD2/CARD15 and the Paneth cell: another piece in the genetic jigsaw of inflammatory bowel disease

Expression of NOD2/CARD15 in the Paneth cell may be critical in the pathogenesis of Crohn’s disease The emergence and application of novel molecular techniques over the last decade has provided a needed catalyst to studies of the pathogenesis of the chronic inflammatory bowel diseases (IBD): Crohn’s disease (CD) and ulcerative colitis (UC). Successful development of genetically engineered models of intestinal inflammation has not only provided insight into the dysregulation of the mucosal immune system characteristic of IBD but has also emphasised the critical and complex role of the bacterial flora in establishing and maintaining chronic intestinal inflammation.1 These advances in understanding pathophysiology in turn have already led to novel therapeutic approaches.2,3 However, it is in studies of human genetics that landmark progress has been made, widely recognised not only within gastroenterology but also by investigators in all complex diseases.4 Genome wide scanning led initially to the identification of a number of susceptibility loci, the statistical evidence for which satisfy stringent criteria for definite linkage.5 The subsequent detection of the NOD2/CARD15 gene6–8 within the IBD1 linkage interval and the association of mutations within this gene with susceptibility to CD is widely regarded as the most stringent proof of principle for hypothesis free genome scanning in complex diseases. In the time that has elapsed since the discovery of NOD2/CARD15, the contribution of this gene in determining susceptibility and disease behaviour in IBD has received detailed examination. It is now clear that NOD2/CARD15 mutations are associated with susceptibility to CD but not UC.6 However, the contribution is subject to considerable ethnic and even regional variation. Whereas mutations may be carried by up to 50% of central Europeans with CD,9 these mutations are not present in Japanese10 or Afro-American11 patients. Even within Europe, …

In vitro measurement of cytotoxic T cell activity does not predict clinical progression in paediatric HIV disease—two case studies

Cytotoxic T cells are believed to be an important immune response in HIV infection, both in the initial response to viraemia, and in controlling HIV replication and maintaining clinical stability. We report here the detailed findings in two vertically infected children, from the Edinburgh perinatal cohort. Both were clinically stable for the first 7 years of life. One had vigorous HIV‐specific cytotoxic T lymphocyte (CTL) responses, and non‐lytic suppression, measured in vitro, while the second had no CTL activity against HIV. Despite her HIV‐specific immunity, the first child had a declining CD4 count, and a high and fluctuating viral load, whereas the second child maintained a stable CD4 count, a low viral load and had a virus which could not be cultured in peripheral blood mononuclear cells (PBMC) in vitro. The first child subsequently progressed to AIDS and has now died, while the second remains clinically well. More detailed investigations showed the clinically stable child to be heterozygous for the CCR5 receptor, and to be HLA‐B49—both of which markers have been associated with slow HIV disease progression. These findings question the role of CTL in maintaining stable HIV disease, and stress the need for immunological investigations to be considered in the light of the genetic make‐up of the patient. They may also reflect a different immunopathogenesis of HIV disease in children compared with adults.

Sex-Differences in the Metabolic Health of Offspring of Parents with Diabetes: A Record-Linkage Study

Maternal diabetes in pregnancy affects offspring health. The impact of parental diabetes on offspring health is unclear. We investigated the impact of parental diabetes on the metabolic-health of adult-offspring who did not themselves have diabetes. Data from the Generation Scotland: Scottish Family Health Study, a population-based family cohort, were record-linked to subjects’ own diabetes medical records. From F0-parents, we identified F1-offspring of: mothers with diabetes (OMD, n = 409), fathers with diabetes (OFD, n = 468), no parent with diabetes (ONoPD, n = 2489). Metabolic syndrome, body, biochemical measurements and blood-pressures were compared between F1-offspring groups by sex. A higher proportion of female OMD had metabolic syndrome than female OFD or ONoPD (P<0.0001). In female offspring, predictors of metabolic syndrome were: having a mother with diabetes (OR = 1.78, CI 1.03–3.07, [reference ONoPD]), body mass index (BMI, OR = 1.21, CI 1.13–1.30) and age (OR = 1.03, CI 1.01–1.06). In male offspring, predictors of metabolic syndrome were: BMI (OR = 1.18, CI 1.09–1.29) and percent body-fat (OR = 1.12, CI 1.05–1.19). In both sexes, OMD had higher blood-pressures than OFD (P<0.0001). In females, OMD had higher glucose (P<0.0001) and percent body-fat (P<0.0001) compared with OFD or ONoPD. OMD and OFD both had increased waist-measurements (P<0.0001), BMI (P<0.0001) and percent body-fat (P<0.0001) compared with ONoPD. Female OMD and OFD had lower HDL-cholesterol levels (P<0.0001) than female ONoPD. Parental diabetes is associated with higher offspring-BMI and body-fat. In female offspring, maternal diabetes increased the odds of metabolic syndrome, even after adjusting for BMI. Further investigations are required to determine the mechanisms involved.

Gut mucosal immunity to tissue transglutaminase in untreated celiac disease and other gastrointestinal disorders.

Tissue transglutaminase antibodies have not previously been measured in gut secretions. IgA anti-tissue transglutaminase and anti-endomysium antibodies were measured in paired serum and whole gut lavage fluid samples from patients with untreated celiac disease (N = 36), other gastrointestinal diseases (N = 235), and healthy volunteers (N = 13). HLA DQ2 typing was performed in the celiac patients. Whole gut lavage IgA anti-tissue transglutaminase antibody concentrations were raised in 83% of celiac patients, 4% of disease controls, and 8% of volunteers, and the antibody concentrations were significantly higher in celiac patients than in controls (P < 0.0001). Whole gut lavage IgA anti-endomysium antibodies were positive in 67% of celiac patients, but in none of the controls. Whole gut lavage, but not serum, IgA anti-tissue transglutaminase antibody concentrations were significantly higher in DQ2 positive than negative celiac patients. In conclusion, whole gut lavage IgA anti-tissue transglutaminase antibody concentrations are higher in untreated celiac disease than in other gastrointestinal diseases.

Epigenetics and Diet in Pregnancy

A good diet during pregnancy is essential for the well-being of the mother and the development of a healthy baby. There is evidence that long-term problems for the baby may arise when the mother’s nourishment is less than ideal. Epigenetic processes are proposed as a key mechanism by which maternal nutrition influences offspring’s life-long health. In this chapter, we consider the evidence supporting this hypothesis. We review the literature describing the effects of extreme under-nutrition in pregnancy on the offspring, through studies of the long-term effects of unexpected famine. We consider the effects of over-nutrition in pregnancy, addressing the long-term outcomes of maternal obesity and diabetes during pregnancy on the offspring. We describe the evidence for the involvement of epigenetic mechanisms, particularly DNA methylation, as mediators of these effects. Finally, we suggest that paternal nutrition may also affect offspring outcomes through epigenetic changes in sperm and that these may affect the health of subsequent generations through the paternal lineage.