Cyclophosphamide post-haploidentical stem cell transplantation experience in an infant with IPEX syndrome

BACKGROUND: IPEX syndrome is a rare hemizygous X-linked disorder with complex autoimmune reactions, characterized by immune dysregulation, polyendocrinopathy, and enteropathy. It has a poor prognosis and a high mortality risk without prompt therapy. Treatment options include pharmacological immunosuppression, nutritional and supportive care, and hematopoietic stem cell transplantation, the latter as the only curative option. CASE REPORT: We present the case of a male infant, the second child of a nonconsanguineous couple, with negative prenatal screening and intrauterine growth restriction detected at 27 weeks' gestation. He was diagnosed with neonatal diabetes mellitus and treated with insulin. He was re-hospitalized for secretory diarrhea and rotavirus infection. At that moment, he was diagnosed with failure to thrive and hypothyroidism. He acquired multiple severe infections, including Candida parapsilosis fungemia, an urinary infection caused by extended-spectrum β-lactamase-producing Escherichia coli, and Klebsiella pneumoniae bacteremia. Endoscopy biopsy revealed chronic duodenitis with the absence of goblet and Paneth cells, findings suggestive of autoimmune enteropathy. Genetic testing identified a mutation in the FOXP3 gene, confirming the diagnosis of IPEX syndrome. We performed a hematopoietic stem cell transplantation from an alternative haploidentical donor and administered a cyclophosphamide post-transplant regime. At 320 days posttransplant, the patient fully recovered his nutritional status and immunity. CONCLUSION: Haploidentical transplantation with a post-transplant cyclophosphamide regime can be a viable therapeutic option for patients with IPEX syndrome, lacking an HLA-identical donor, with promising outcomes based on the follow-up data.