Evidence relating to the efficacy of Helicobacter pylori eradication therapy for chronic immune thrombocytopenic purpura (cITP) in childhood is inadequate. The aim of this retrospective study was to determine the efficacy of H. pylori eradication therapy for platelet response in pediatric patients with cITP in our hospital, and to perform a systematic review of previous reports about pediatric patients with cITP who were positive for H. pylori infection and were treated with H. pylori eradication therapy. Analysis of the data of pediatric patients with cITP in our hospital and a systematic review of digital literature databases of studies in pediatric patients with cITP were performed. Data of 33 pediatric patients with cITP from our hospital records showed that the prevalence of H. pylori infection and the rate of response to platelet therapy were 15% and 33.3%, respectively. Data of 706 pediatric patients from 18 previous reports showed that the prevalence of H. pylori infection and rate of platelet response were 23% and 43.8%, respectively. Eradication therapy for H. pylori infection in pediatric cITP patients can be expected to result in a response equivalent to that in the adult population, with fewer adverse effects than other treatments for cITP.

Food protein-induced enterocolitis syndrome caused by solid foods (Solid-FPIES) is a non-immunoglobulin E-mediated allergic disease characterized by delayed gastrointestinal symptoms. An oral food challenge (OFC) test, although necessary, can be inconclusive in cases with mild symptoms. Moreover, limited diagnostic marker availability highlights the need for novel surrogate markers. We aimed to examine the efficacy of fecal hemoglobin (FHb), lactoferrin (FLf), and calprotectin (FCp) over time in evaluating gastrointestinal inflammation degree in Solid-FPIES. This observational study included 40 patients and 42 episodes at Juntendo University Hospital and affiliated hospitals between October 2020 and March 2024 categorized into FPIES (12 patients with 11 egg yolk, 1 fish, and 1 soybean episodes), control (14 patients with 15 episodes), and remission (14 patients). Fecal tests were performed for 7 days following antigen exposure. The ratios of each value were divided by the baseline value and analyzed over time course. The FPIES group had significantly higher peak ratios of all fecal markers than the control group (p < 0.01). The median FHb, FLf, and FCp ratios were 3.25, 9.09, and 9.79 in the FPIES group and 1.08, 1.29, and 1.49 in the control group, respectively. In the remission group, several patients had fluctuating fecal markers despite negative OFC, and one patient was diagnosed with FPIES by OFC with increased load. Receiver operating characteristic curve analyses revealed high diagnostic performance for each fecal marker in FPIES. Sequential fecal marker examination proved valuable in diagnosing Solid-FPIES and evaluating the degree of gastrointestinal inflammation.

Mild Th1 and Th17 immune responses in childhood against Helicobacter pylori are presumed to be responsible for H. pylori colonization and mucosal atrophy reduction. However, the mechanism remains unclear. In this study, we aimed to investigate the childhood-specific immune responses observed after H. pylori infection by analyzing galectin expression in the gastric mucosa. We focused on galectin-1 (Gal-1) and galectin-9 (Gal-9), which function to suppress Th1 and Th17 immune responses. We analyzed changes in the expression of Gal-1 and Gal-9 in the gastric mucosa of pediatric patients with H. pylori infection. Ten pediatric patients with and ten patients without H. pylori infection who underwent biopsy to assess the cause of chronic abdominal symptoms using esophagogastroduodenoscopy were evaluated. Gal-1 and Gal-9 expression in the biopsy tissues of the gastric antrum and corpus was analyzed by immunohistochemical staining. Gal-1 expression was significantly increased in the stromal cells of the corpus owing to H. pylori infection. No alterations in Gal-1 expression due to H. pylori infection were observed in the antral tissue. Helicobacter pylori infection considerably increased Gal-9 expression in all tissues. According to previous reports, the increased expression of Gal-9 associated with H. pylori infection is not observed in adults. Therefore, the increased expression of Gal-9 associated with H. pylori infection is specific to pediatric patients. The increased expression of Gal-1 and Gal-9 may suppress Th1 and Th17 immune responses against H. pylori infection during childhood, promote H. pylori colonization, and reduce inflammation in the gastric mucosa of pediatric patients.

Juvenile polyps, typically localized in the rectum and sigmoid colon, are a common cause of pediatric bloody stool. An isolated small intestinal juvenile polyp is uncommon and generally difficult to diagnose. The first case of an isolated juvenile polyp diagnosed by abdominal ultrasonography before acute abdomen had developed and resected by double-balloon endoscopy is presented along with a review of previous reports including this case. A two-year-old Japanese boy was referred to our institute for further evaluation of anemia persisting from one year of age. Laboratory findings showed mild iron deficiency anemia and elevated fecal human hemoglobin (Hb) and fecal calprotectin values. Upper and lower endoscopic findings showed no abnormalities. Because the abdominal ultrasonography performed one year later demonstrated a 15 mm jejunal polyp, combined with a similar finding on small intestinal capsule endoscopy, this was diagnosed as an isolated lesion. The lesion was resected by cautery with double-balloon endoscopy and diagnosed as a juvenile polyp pathologically. All clinical symptoms disappeared, and all laboratory data improved after treatment, without recurrence for more than one year after the procedure. Abdominal ultrasonographic screening and the fecal calprotectin value led to the diagnosis and non-surgical invasive treatment of an isolated small intestinal juvenile polyp.