Faculty Bibliography

OBJECTIVES: To determine whether children with celiac disease (CD) fail to show a response to hepatitis B virus (HBV) vaccine more frequently than children without CD. PATIENTS AND METHODS: This was a prospective study that compared the response to HBV, tetanus, rubella, and Haemophilus influenzae type b (Hib) vaccines between children with CD and age- and sex-matched control subjects. RESULTS: The study population included 26 patients with CD and 18 age- and sex-matched controls. All had received the full complement of childhood vaccinations. A significantly higher proportion of subjects in the CD group (14 of 26) failed to respond to HBV vaccine compared with controls (2 of 18; 53.9% vs 11.1%; P < 0.05). Patients with CD were 8.33 times more likely to test negative for hepatitis B surface antigen than control subjects (95% CI, 1.5-46.5). By contrast, all of the subjects in both groups tested positive for rubella antibodies; only 1 subject in the CD group tested negative for tetanus antibody versus none in the control group (3.9% vs 0%; P = 1.0). The percentage of subjects who tested negative for Hib antibodies was similar in the 2 groups (CD, 33.3%; control, 44.4%; P = 0.53). CONCLUSIONS: More than 50% of children with CD do not show a response to standard vaccination regimens for HBV. Given the large number of children with CD throughout the world, this observation suggests that there is a large HBV-susceptible population despite widespread vaccination. Current immunization strategies may need to be reassessed to protect this population and achieve the goal of universal protection.

Capsule endoscopy is a relatively new technology that has allowed gastroenterologists to visualize the mucosa of the small intestine. This technology is playing an expanding role in both adult and pediatric gastroenterology. In this report, we present an 8-yr-old child following allogeneic hematopoietic cell transplantation who developed large volume bloody diarrhea requiring multiple packed red blood cell transfusions that was resistant to aggressive therapy for GVHD. The capsule endoscopy performed on this patient provided significant information not provided by upper endoscopy and colonoscopy that allowed for successful treatment changes. This case demonstrates that capsule endoscopy is a diagnostic tool that may play an important role in the assessment of patients, including children, with possible GVHD

OBJECTIVES: Infliximab, an anti-tumor necrosis factor (TNF) monoclonal antibody, might exert some of its long-term therapeutic effects in Crohn's disease (CD) by interacting directly with cells of the immune system such as monocytes and T lymphocytes via membrane TNF and by inducing apoptosis. Accordingly, the effects of inflix-imab on monocyte apoptosis and down-regulation of proinflammatory cytokines (reverse signaling) were assessed. METHODS: To assess apoptosis, monocytes from healthy individuals (controls) and CD patients were incubated in the presence or absence of infliximab or the apoptotic agent gliotoxin for 24 hours. Annexin V staining and the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-FITC nick end labeling assay were used to measure early and late apoptosis. To measure the effects of infliximab on reverse signaling, monocytes from healthy individuals pretreated in vitro with infliximab were stimulated with lipopolysaccharide or staphylococcal enterotoxin A, and the induction of the proinflammatory cytokines, TNF-alpha, interleukin (IL)-1beta, IL-6, and IL-8 was measured by reverse transcription polymerase chain reaction. The effect of in vivo infliximab treatment of monocytes was similarly determined by comparing the responses of monocytes from CD patients before and immediately after infliximab infusion. RESULTS: Infliximab did not induce apoptosis of monocytes from either healthy individuals or CD patients but rather stabilized them. However, monocytes from healthy individuals treated with infliximab in vitro, or from CD patients infused with infliximab, produced significantly less TNF and other proinflammatory cytokines when stimulated with the bacterial products lipopolysaccharide and staphylococcal enterotoxin A. CONCLUSIONS: Apoptosis of monocytes is not responsible for the therapeutic effects of infliximab. However, some of the therapeutic effects of infliximab may be caused by its ability to down-regulate proinflammatory cytokines production by monocytes exposed to bacterial antigens

OBJECTIVES: Young children are thought to be a unique subset of pediatric patients with inflammatory bowel disease (IBD). The authors' objective was to evaluate the differences in initial clinical presentation of young and older children with IBD and to determine whether a positive family history of IBD is associated with the age of presentation. METHODS: The authors reviewed the records of all patients with new diagnoses of Crohn disease (CD) and ulcerative colitis (UC) who presented between July 1996 and July 1999. Initial evaluation included assessment of growth parameters and laboratory values (hemoglobin concentration, platelet count, erythrocyte sedimentation rate, and serum albumin). Inquiry regarding a family history of IBD was made in every patient. RESULTS: There were 153 patients with new diagnoses (82 with CD and 71 with UC), with a mean age of 11.9 years (range, 16 months-18 years). The children with CD had a higher sedimentation rate and platelet count and a lower mean hemoglobin concentration and serum albumin at presentation than did children with UC. Body mass index (BMI) was significantly lower in patients with newly diagnosed CD than in those with UC. The only significant laboratory differences between patients younger than 11 years and those 11 years or older was a higher mean platelet count in patients with CD who were younger than 11 years. Of the younger patients with CD, 41.7% had a positive family history of IBD, which was significantly greater that that found in the older patients with CD. CONCLUSIONS: Except for higher platelet counts, a lower BMI, and a higher frequency of positive family history in young children with CD, there were no significant differences in the presentation of young children with IBD compared with older children.

OBJECTIVE: Recent reports indicate that allelic variants in NOD2/CARD15 are associated with Crohn's disease (CD) susceptibility, and that homozygosity or compound heterozygosity at this locus for any of three recently defined sequence variants confers a greatly increased risk of CD. These sequence changes include two missense mutations, R702W and G908R, and a frameshift insertion, 1007insC. The aim of this study was to determine the frequency of these NOD2/CARD15 variants in familial and sporadic CD patients in the Ashkenazi population and to determine their effects on disease susceptibility and age of disease onset (AOO). METHODS: Allele and genotype frequencies of these three variants were determined in 481 CD patients of Jewish descent and 110 Jewish controls; 169 patients had a family history of CD, and 312 were 'sporadic' cases. Variants were detected by polymerase chain reaction using allele-specific primers labeled with fluorescent dye. RESULTS: Familial cases had a significantly higher frequency of the G908R variant than sporadic cases (0.127 vs 0.059, p = 0.0003) and correspondingly, a significantly higher proportion of homozygotes and compound heterozygotes (11.8% vs 4.5%, p = 0.0027). Homozygotes and compound heterozygotes had an OR for CD of 14.6 for familial cases and 5.1 for sporadic cases. There was no increased risk of CD for simple heterozygotes. The AOO was significantly lower for CD patients who were homozygotes and compound heterozygotes for NOD2/CARD15 (17.5 vs 22.4 yr, p = 0.04), but only for familial cases. CONCLUSIONS: NOD2/CARD15 contributes more to CD susceptibility in familial cases than in sporadic cases, and to an earlier AOO. There is no increased risk of CD for individuals carrying only a single copy of these NOD2/ CARD15 variants, whereas individuals carrying two copies have a 5-15-fold increased risk. The penetrance of the NOD2/CARD15 mutations was estimated at less than 1%

Polyglutamine expansion causes the disease proteins to aggregate, resulting in stable insoluble aggregates in the nucleus. The in vitro aggregation and cellular toxicity of polyglutamine proteins are reduced by chaperone heat shock proteins (Hsp). In polyglutamine disease animal models, however, polyglutamine inclusions remain in the nucleus despite the suppression of neurodegeneration by Hsp. Studies using yeast genetic approach revealed that the balance of Hsp is important for regulating protein aggregation in the cytoplasm of yeast cells. Here we report that N-terminal fragments of huntingtin with an expanded polyglutamine tract form aggregates only in the cytoplasm of yeast cells and, when tagged with nuclear localization sequences (NLS), are able to aggregate in the nucleus. Deletion of the Hsp104 gene prevents the aggregation of huntingtin in the cytoplasm but is unable to eliminate the aggregation of NLS-tagged huntingtin in the nucleus. The inhibitory effect of Hsp104 deletion on the cytoplasmic aggregation of huntingtin only occurs in viable yeast cells, as aggregates can be formed in Hsp104 deletion cells that have been frozen for 72 h. Fresh cytosolic extracts of the Hsp104 deletion strain inhibit the aggregation of huntingtin in vitro, suggesting that the deletion of Hsp104 may alter the activities of other cytoplasmic factors to inhibit polyglutamine aggregation in the cytoplasm. We propose that the regulatory effects of chaperones may mainly be restricted to the cytoplasm and have much less influence on polyglutamine-containing aggregates in the nucleus.

BACKGROUND: Active colitis in patients with inflammatory bowel disease is associated with mucosal vasodilation, increased intestinal permeability and abnormal colonic motility. Nitric oxide is a messenger molecule with many functions, including regulation of local blood flow, vasomotor tone, and inflammation. Increased nitric oxide production and inducible nitric oxide synthase activity have been demonstrated in experimental models of colitis. This study was designed to determine the relationship between nitric oxide production and colonic inflammation in children with active colitis and in control subjects and whether expression of inducible nitric oxide synthase protein is demonstrable in the intestinal epithelium of these patients. METHODS: Nitrate + nitrite were measured in urine, stool, and plasma using the Griess assay. Expression of inducible nitric oxide synthase protein in intestinal tissue was determined by immunohistochemical localization. RESULTS: Urinary nitrate + nitrite levels were not significantly different in patients and control subjects. In contrast, stool and plasma nitrate + nitrite concentrations were significantly higher in children with inflammatory bowel disease compared with levels in control children (stool: 162.4 +/- 31.0 mumol/l versus 77.2 +/- 22.1 mumol/l; plasma: 65.2 +/- 9.9 mumol/l versus 38.1 +/- 6.6 mumol/L; p < 0.05). Stool nitrate + nitrite levels significantly correlated with plasma values. Immunohistochemical staining of colonic tissue from children with inflammatory bowel disease demonstrated inducible nitric oxide synthase protein located exclusively in epithelial cells. CONCLUSION: Increased nitric oxide production and enhanced intestinal epithelial cell expression of inducible nitric oxide synthase protein are associated with active colonic inflammation.

Previous studies have demonstrated enhanced intestinal trypsin uptake and decreased liver clearance of trypsin in newborn rats compared to adults. In order to examine the effectiveness of the reticuloendothelial system (RES) in clearing trypsin, bovine trypsin (1.25 mg/100 g body weight) plus trace 125I-trypsin were injected into the portal vein of 2-week-old (n = 57) and adult (n = 44) control rats or following RES stimulation using intraperitoneally injected lipopolysaccharide or RES suppression with intraperitoneally injected oleic acid emulsion. Plasma, liver and spleen 125I activities were assessed at 1, 5 or 15 min following infusion in control, stimulated and suppressed animals. Newborn control rats had significantly increased 125I plasma levels with decreased liver and spleen 125I activity compared to control adults. RES stimulation in the newborns did not lead to any change in liver or plasma levels although splenic values increased while adults had a decrease in liver 125I activity. RES suppression in the newborns led to increased plasma and decreased spleen 125I-trypsin values while adult rat levels were unchanged. The immature reticuloendothelial system in newborns is poorly responsive to RES stimulation although it can be made even further inefficient by RES suppression. The combination of RES immaturity and lack of response to stimulation may make newborns susceptible to proteolytic damage, especially during times of increased systemic levels of proteolytic enzymes.

Our aims were to determine the long-term clinical and manometric follow-up of 11 children with previously documented esophageal dysmotility, who had been breast-fed by mothers with silicone breast implants, their response to prokinetic agents, and to analyze changes in macrophage activation. Seven of 11 children had subjective clinical improvement. Weight/ height ratios remained the same or improved in 9/11. Biopsies at follow-up endoscopy were either normal or demonstrated mild esophagitis in 8/10. LES and UES pressures and percent propagation were not significantly different at follow-up, while wave amplitude significantly increased. Following intravenous metoclopramide, LES pressure, percent propagation, and wave amplitude significantly increased while UES pressure was unchanged. Urinary neopterin significantly decreased at follow-up, while urinary nitrates were unchanged. Esophageal dysmotility is chronic in this group of children, suggesting persistent autonomic nervous system dysfunction. Prokinetic agents may be useful in long-term management. The decreasing urinary neopterin levels suggest that, ultimately, there may be improvement in esophageal motility.