Harnessing Cytomegalovirus DNAemia and CMV-Specific Cell-Mediated Immunity in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients.

BACKGROUND

Recovery via cytomegalovirus (CMV)-specific cell-mediated immunity (CMI) in pediatric hematopoietic stem cell transplantation (HSCT) recipients is associated with a lower incidence of significant CMV DNAemia and disease. This study aimed to determine whether early post-HSCT CMI monitoring could predict CMV infection outcomes and identify factors that influence CMI recovery.

METHODS

Pediatric patients (≤ 19 years) undergoing allogeneic HSCT at Asan Medical Center Children's Hospital between August 2018 and February 2020 were prospectively enrolled. CMV-specific CMI was assessed using the enzyme-linked immunospot assay for phosphoprotein 65 (pp65) or immediate-early protein 1 (IE-1) antigens at pre-transplantation, and 1 and 3 months post-transplantation. Plasma CMV polymerase chain reaction monitoring was conducted regularly, and the incidence of CMV DNAemia and CMV disease was evaluated over a two-year follow-up period.

RESULTS

Of the 55 enrolled pediatric recipients, CMV DNAemia occurred in 74.5%, with 21.8% of cases progressing to significant CMV DNAemia. Cumulative CMI recovery rates at 3 months were 61.8% for pp65 and 43.6% for IE-1. Recipients with a cumulative recovery of pp65-specific CMI exhibited a significantly lower incidence of significant CMV DNAemia and CMV disease. In contrast, the cumulative recovery of IE-1-specific CMI was not associated with CMV outcomes. In the multivariate analysis, haploidentical donor status and post-HSCT CMV DNAemia were independently associated with impaired cumulative recovery of both pp65- and IE-1-specific CMI.

CONCLUSION

Monitoring pp65-specific CMI recovery within three months post-HSCT is valuable for predicting significant CMV infection in pediatric recipients. Haploidentical HSCT recipients demonstrated impaired CMI recovery, highlighting the need for careful monitoring and tailored prophylactic strategies.