Serum leucine-rich α-2 glycoprotein (LRG) is widely used as a biomarker of disease activity in the management of inflammatory bowel disease (IBD). While its utility has been demonstrated in pediatric IBD, the role of serum LRG in monogenic IBD remains unclear. This report describes the association between the clinical course of gastrointestinal symptoms and serum LRG levels before and after allogeneic hematopoietic cell transplantation (HCT) in an infant with Wiskott-Aldrich syndrome (WAS) complicated by IBD.
A 57-day-old male infant presented to our hospital with subcutaneous hemorrhage, thrombocytopenia, and generalized eczema as the primary complaints; genetic testing confirmed a diagnosis of WAS. At 3 months of age, he developed bloody stools, and lower gastrointestinal endoscopy revealed ulcers and erosions in the colon. Histopathological examination showed infiltration of inflammatory cells and a reduction in goblet cells, leading to a diagnosis of WAS-associated IBD. Despite treatment with an elemental diet, oral 5-aminosalicylic acid, and prednisolone, poor weight gain and bloody stools persisted. Cytomegalovirus (CMV) viremia worsened despite antiviral therapy, and systemic complications of WAS, such as thrombocytopenia and colitis, remained uncontrolled; therefore, at 10 months of age, the patient underwent HCT from an HLA-matched unrelated donor following conditioning with fludarabine and busulfan. Neutrophil engraftment was achieved on day 24. No acute graft-versus-host disease was observed. Bloody stool resolved after the start of conditioning, and remission stabilized following engraftment of donor cells. Serum LRG concentration peaked at 50.2 µg/mL prior to HCT but gradually decreased after the start of conditioning, reaching 14.0 µg/mL by day 90. No recurrence of colitis has been observed during the 5 months following HCT.
In this case, disease activity in WAS-associated IBD showed a good correlation with serum LRG levels. Since clinical significance may vary depending on the underlying genetic defect and the immune pathways involved, further cases are needed to establish the interpretation of serum LRG in IEI-associated IBD.
