Case Report: Unmanipulated Matched Sibling Donor Hematopoietic Cell Transplantation In TBX1 Congenital Athymia: A Lifesaving Therapeutic Approach When Facing a Systemic Viral Infection

Congenital athymia can present with severe T cell lymphopenia (TCL) in the newborn period, which can be detected by decreased T cell receptor excision circles (TRECs) on newborn screening (NBS). The most common thymic stromal defect causing selective TCL is 22q11.2 deletion syndrome (22q11.2DS). T-box transcription factor 1 (TBX1), present on chromosome 22, is responsible for thymic epithelial development. Single variants in TBX1 causing haploinsufficiency cause a clinical syndrome that mimics 22q11.2DS. Definitive therapy for congenital athymia is allogeneic thymic transplantation. However, universal availability of such therapy is limited. We present a patient with early diagnosis of congenital athymia due to TBX1 haploinsufficiency. While evaluating for thymic transplantation, she developed Omenn Syndrome (OS) and life-threatening adenoviremia. Despite treatment with anti-virals and cytotoxic T lymphocytes (CTLs), life threatening adenoviremia persisted. Given the imminent need for rapid establishment of T cell immunity and viral clearance, the patient underwent an unmanipulated matched sibling donor (MSD) hematopoietic cell transplant (HCT), ultimately achieving post-thymic donor-derived engraftment, viral clearance, and immune reconstitution. This case illustrates that because of the slower immune recovery that occurs following thymus transplantation and the restricted availability of thymus transplantation globally, clinicians may consider CTL therapy and HCT to treat congenital athymia patients with severe infections.

Growth in the face of overwhelming pressure: A narrative review of sibling donor experiences in pediatric hematopoietic stem cell transplant

Sibling donation in pediatric hematopoietic stem cell transplant (HSCT) can be emotionally distressing for children, but may simultaneously evoke positive emotions, and has the potential to facilitate personal growth. We conducted a narrative review of sibling donor experiences, which included an analysis of psychosocial distress and post-traumatic growth (PTG). We searched the following databases: MEDLINE, CINAHL, PsycInfo, and SCOPUS. Search concepts used to develop key terms included HSCT, siblings, children, and psychosocial outcomes. Specific inclusion criteria included a) research articles published in English in peer-reviewed journals until September 2020, and b) reported trauma symptoms and PTG characteristics of sibling donation experiences. Four themes were identified: fear and anxiety related to HLA testing, overwhelming pressure to donate, guilt and blame when the ill child died, as well as emotional and physical isolation following donation. Sibling responses also included evidence of PTG, articulated as a deepened appreciation for life, closer relationships with the ill child and other family members, increased personal strength, and spiritual growth. These results highlight a critical need for future research approaches that further empower sibling donor voices, such as those found in participatory, arts-based methodologies.