Absolute CD3+ T-Cell Counts After Anti-Thymocyte Globulin: Impact on Graft and Infectious Outcomes in Pediatric...

Rabbit anti-thymocyte globulin (r-ATG) is a thymocyte depleting agent for the induction of immunosuppression in kidney transplant recipients (KTRs). There is little data comparing a level of CD3+ T-cell suppression for optimal graft outcomes with minimized infectious risk.

KTRs from January 2020 to January 2024 were included if they met these criteria: (1) < 21 years of age at transplantation, (2) no previous receipt of a solid organ or hematopoietic stem cell transplant, (3) completion of a r-ATG-based induction protocol, (4) had absolute CD3+ T-cell counts quantified at induction, and (5) at least 6 months posttransplant follow-up. Patients were grouped based on their CD3+ cell counts during or within 24-h of induction (< 25 cells/mm³ vs. ≥ 25 cells/mm³) and statistical comparisons were made.

Of 111 KTRs reviewed, 28 were included. A CD3+ cell count < 25 was achieved in 22/28 (79%) recipients, following a median r-ATG dose of 4.35 mg/kg (IQR: 3.00-4.55). The median age was 15 years (IQR: 13.50-16.75). The median dose of r-ATG administered by completion of induction was 4.530 mg/kg (IQR: 4.434-4.737) and did not differ between groups (p = 0.758). There was no difference in the rate of rejection, infectious markers, or hospitalization based on CD3+ levels. There was no mortality or graft loss.

There were no observed differences in post-transplant outcomes when compared by CD3+. As the dose of r-ATG delivered and outcomes were similar, monitoring of CD3+ T-cell populations during induction may not be necessary.