Very rarely, patients with X-linked lymphoproliferative syndrome type 1 present central nervous system vasculitis. We report a patient carrying a SH2D1A mutation that, after treatment for lymphoma developed fatal central nervous system vasculitis. He lacked signs of ongoing Epstein–Barr virus infection. We propose that impaired T cell homeostasis caused by SAP deficiency facilitates aberrant CD8+ T cell activation against vascular antigens promoting clinical manifestations.
From the *Department of Pediatrics, Primary Immunodeficiencies Unit, Hospital Dona Estefânia- CHLC, EPE
†Department of Pediatrics, CEDOC, Chronic Diseases Research Center, NOVA Medical School, Lisbon, Portugal
‡Centre for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institute, Karolinska University Hospital Huddinge
§The Childhood Cancer Research Unit, Department of Women’s and Children’s Health, Karolinska Institute, Karolinska University Hospital Solna
¶The Clinical Genetics Unit, Department of Molecular Medicine and Surgery, and Center for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
‖Department of Pediatrics, Neurology Service, Hospital Dona Estefânia- CHLC, EPE, Lisbon, Portugal
**Hospital CUF Descobertas, Immunoallergy Department, Lisbon, Portugal.
Accepted for publication May 21, 2018.
A written informed consent from the patient’s mother has been obtained.
The authors have no funding or conflicts of interest to disclose.
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Address for correspondence: João Farela Neves, ORCID 0003-3963-2331, Infectious Diseases Unit, Primary Immunodeficiencies Unit, Hospital Dona Estefania, Pediatric University Hospital, Rua Jacinta Marto, 1169-045 Lisbon, Portugal. E-mail: firstname.lastname@example.org.