MEMORY T cell therapy following allogeneic haematopoietic cell transplantation shows promising efficacy in clearing infections and improving immune recovery, according to new data presented at the 52nd Annual Meeting of the EBMT.
Memory T Cell Therapy Improves Infection Clearance
In this retrospective study of 20 adult patients, investigators evaluated CD45RA depleted donor memory T cell infusion for refractory or persistent infections after transplantation. Viral infections accounted for 90% of cases, including Epstein Barr virus, cytomegalovirus, and adenovirus, while fungal infections such as Fusarium and Aspergillus comprised 10% and 5% respectively. Patients received a total of 48 infusions, with a median of two treatment cycles and a cumulative dose of 23.2×10⁶ cells/kg.
After a median follow up of 52 days, 18 (90%) of patients were alive, and 60% achieved complete remission of infection. Among those with viral infections (18), 72.2% reached negative polymerase chain reaction results following therapy. Time to viral clearance varied, ranging from five days for cytomegalovirus to 38 days for parvovirus B19. Clinical improvement was also observed in patients with fungal infections.
Treatment Timing and Immune Recovery
The first infusion was administered at a median of 98 days after transplantation, with half of patients (n=10) receiving therapy within 100 days. Memory T cells were primarily derived from the original transplant donor in 75% of cases, with the remainder sourced from third party donors. Notably, 70% of patients continued immunosuppressive therapy during treatment, indicating that the intervention may be effective even in immunocompromised settings.
The findings support previous evidence that memory T cells, characterised by CD45RO expression and absence of CD45RA, can accelerate immune reconstitution and enhance anti infection responses following transplantation.
Safety Profile and Clinical Implications
Treatment was well tolerated overall. Adverse events included acute graft versus host disease in 5% of patients and chronic graft versus host disease in 15%, alongside one reported relapse of the primary disease. No unexpected safety concerns were identified.
These findings suggest that CD45RA depleted donor memory T cell therapy may offer a viable strategy to address persistent infections following transplantation. Given the high burden of infection related morbidity and mortality in this population, the approach may represent an important adjunct to existing prophylactic and therapeutic strategies. Further research in larger cohorts will be essential to confirm these results and refine patient selection.
Reference
Huang J et al. The efficacy of memory T cell donor lymphocyte infusion in augmenting immune function following allogeneic hematopoietic cell transplantation. Abstract A113. EBMT 52nd Annual Meeting; 22-25 March 2026.
