Analysis of T Cell and Natural Killer (NK) Cell in Relation to Viral Infections in Pediatric Stem Cell Transplant Patients and Donors

Analysis of KIR+CD56+ T Cells and FcRg-CD56+CD3- NK Cells in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Patients and Donors

Viral infections and reactivation during pediatric allogeneic hematopoietic stem cell transplantation (HSCT) are a common occurrence and significantly contribute to post-transplant morbidity and mortality. The risk is high due to prolonged periods of immune deficiency while awaiting immune reconstitution post-transplant. Current strategies to reduce complications from viral infections include prophylactic treatment, close monitoring for viral infections and prompt treatment at the first sign of symptoms or increasing viral load. However, the most definitive treatment for viral infections remains the host's cellular defenses. Improved understanding of the immune systems response to viral infections may lead to better treatment strategies.

This study is being done to explore the relationships between T-cells and NK cells (infection fighting cells) and viral infections or reactivations in young allogeneic stem cell transplant patients. The investigators will be looking at how these cells react and function in young patients receiving allogeneic stem cell transplantation, as well as in healthy stem cell donors.

PRIMARY OBJECTIVE:

• To explore the expansion patterns of KIR+CD56+ T-cells and FcRg-CD56+CD3- NK cells in response to viral infection and reactivation in pediatric allogeneic hematopoietic stem cell transplant (HSCT) patients.

SECONDARY OBJECTIVES:

• To describe the phenotype of KIR+CD56+ T-cells and FcRg-CD56+CD3- NK cells in pediatric allogeneic HSCT patients and healthy donors.
• To describe the specificity and functional capacity of KIR+CD56+ T-cells against viral antigens in both pediatric allogeneic HSCT patients and healthy donors.
• To describe the functional capacity of FcRg-CD56+CD3- NK cells against CMV-infected cells in both pediatric allogeneic HSCT patients and healthy donors.

Inclusion Criteria:

• Patients undergoing allogeneic hematopoietic stem cell transplant (HSCT) for a hematologic malignancy or a donor for a patient undergoing allogeneic hematopoietic stem cell transplant for a hematologic malignancy.
• For HSCT patients: ages birth to 21 years old; for donors: any age.
• For minors less than 18 years old, both parents must be available on St. Jude campus to provide consent. One parent/legal guardian will be acceptable if one parent is deceased, incompetent, or when the one parent present has legal responsibility for the care and custody of the child.

Exclusion Criteria:

• Patients undergoing allogeneic hematopoietic stem cell transplant for a disease other than a hematologic malignancy