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Collagenous sprue (CS) is a severe malabsorption disorder, the etiology of which has not been well defined. Herein, we report the case of a 3-month-old infant with CS who responded to steroid and immunomodulator treatment and presented a thick subepithelial collagen band. A 3-month-old Japanese girl presented with severe watery diarrhea that lasted for 2 weeks. She was admitted to the referring hospital, but symptomatic improvement was not achieved with fasting and rehydration. Gastroduodenal endoscopy showed an edematous duodenal mucosal surface. Duodenal biopsy indicated severe villous atrophy with infiltration of mostly CD8-positive T cells; and deposition of subepithelial collagen was confirmed. The subepithelial collagen deposits, however, had disappeared after treatment. Historically, child-onset CS is extremely rare and this case is likely to be the youngest case of infantile CS. The present case suggests that CS should be considered as a differential diagnosis for intractable diarrhea, even in infants.

Background Although pediatric inflammatory bowel disease (IBD) is characterized by extensive intestinal involvement and rapid early progression, the precise cause and specific factors involved in disease aggravation have not been well established. The aim of this study was to investigate the pathogenesis of pediatric IBD. Methods The expression of inflammatory molecules in colon samples taken from active ulcerative colitis (UC) and Crohn's disease (CD) patients was compared with those of controls. Three children each with UC and CD in both the active and remission phase and their controls were enrolled, and the inflammatory gene expression in the mucosa was examined by microarray. Additionally, six children from each group were further enrolled in a real-time reverse transcription polymerase chain reaction and an immunohistochemical study to examine the expression of CXCL9, 10, 11, CXCR3, matrix metalloproteinase (MMP)-1, -3, -7, and -10. Results The microarray analysis revealed enhanced expression of the CXCL9, 10, and 11 genes in the active phase of CD. The expression of MMP-1, -3, -7, and -10 was significantly enhanced in the active phase of UC. These changes were also confirmed by real-time reverse transcription polymerase chain reaction. Immunohistochemical analysis revealed enhanced expression of CXCL9, 10, and 11 in both the lamina propria and epithelial cells in these patients. CXCR3-positive cells were also confirmed in the lamina propria. The expression of MMP-1, -3, -7, and -10 was also enhanced in the mucosal epithelial cells and the lamina propria in both CD and UC patients. Conclusions These findings suggest that CXCR3 axis components and MMP play an important role in the mucosal damage in pediatric IBD.

Background Although rectal bleeding in infancy (RBI) is not a rare phenomenon, the clinical course of RBI is not fully understood. Methods To investigate the outcome and pathogenesis of RBI, especially when concomitant with food-protein-induced proctocolitis (FPIP) and neonatal transient eosinophilic colitis (NTEC), 22 neonates with rectal bleeding with FPIP and NTEC from January 2008 to June 2012 were enrolled and their clinical course and mechanisms of inflammation were examined. Results Thirteen infants showed rectal bleeding after feeding and were diagnosed with FPIP, and nine infants showed rectal bleeding before feeding and were diagnosed with NTEC. Elevated peripheral white blood cell (12 685 ± 3754/μl and 30 978 ± 16 166/μl) and eosinophil (1084 ± 816/μl and 4456 ± 3341/μl) were confirmed in FPIP and NTEC, respectively. Colonoscopy revealed nodular lymphoid hyperplasia, a pale mucosal surface and oozing with diffuse infiltration of neutrophils, lymphocytes, and eosinophils in both groups. Reverse transcription polymerase chain reaction analysis revealed enhanced expression of the interleukin-6, CCL11, and CXCL13 genes, where CXCL13 expression was more prominent in FPIP. Mucosal infiltration by CD3- and immunoglobulin-A- but not immunoglobulin-E-positive cells was confirmed. Among them, only one infant with FPIP developed milk allergy, whereas none with NTEC had developed milk allergy at the age of 1 year. Conclusions FPIP in infancy and NTEC are similar diseases and interleukin-6, CCL11, and CXCL13 may play a major role in the pathogenesis of rectal bleeding. Although the involvement of allergic reaction is possible, milk allergy was not a common outcome after 1 year of follow up.

Background: Although initial infection with Helicobacter pylori may occur before 5 years of age, the pediatric mucosal immune response against H. pylori is not clear. The aim of the present study was to evaluate immune responses in the H. pylori-infected gastric mucosa of children using microarray and real-time polymerase chain reaction (PCR) analysis of pediatric gastric samples. Methods: Gastric samples were obtained from 12 patients undergoing routine endoscopy of chronic abdominal complaints. Six patients (three boys, three girls) aged 10.1–14.6 years had evidence of H. pylori infection, and the remaining six (three boys, three girls) aged 10.3–15.5 years had no evidence of infection and presented no histological changes associated with gastritis. Microarray and real-time PCR analyses were performed, and the changes in gene expression-related immune response were also analyzed. Results: Using microarray analysis, the total number of significantly upregulated and downregulated genes (fold change >5, P