Levels of C-reactive protein and body temperature elevation during neutropenia predict engraftment and non-relapse mortality for unrelated single-unit cord blood transplantation in adults.

BACKGROUND Cord blood transplantation (CBT) presents unique challenges related to inflammation during neutropenia, such as mucosal damage, infections, and the potential development of pre-engraftment syndrome or pre-engraftment immune reaction. These factors can contribute to significant inflammation and infection shortly after CBT. However, the effect of severe inflammation during neutropenia, specifically elevated C-reactive protein (CRP) level and body temperature, on post-transplant outcomes after CBT remains unclear. OBJECTIVE This retrospective study aimed to investigate the association between maximum CRP level, maximum body temperature during neutropenia, and post-transplantation outcomes in adult patients undergoing single-unit CBT. STUDY DESIGN We retrospectively evaluated the impact of maximum CRP level and maximum body temperature during neutropenia on post-transplantation outcomes in adults who underwent single-unit unrelated CBT between 1998 and 2023 at our institution. RESULTS A total of 336 adult patients were included in this study. The median maximum CRP level before neutrophil recovery was 7.75 mg/dL (interquartile range [IQR], 4.70 to 12.05 mg/dL) at a median of 14 days (IQR, 8 to 16 days). The median maximum body temperature before neutrophil recovery was 39.5°C (IQR, 39.0 to 40.0°C) at a median of 15 days (IQR, 12 to 17 days). In the multivariate analysis, a maximum CRP level≥20 mg/dL was significantly associated with lower neutrophil recovery (hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.23 to 0.59; P<0.001), lower platelet recovery (HR, 0.28; 95% CI, 0.16 to 0.48; P<0.001), and a higher incidence of veno-occlusive disease/sinusoidal obstruction syndrome (HR, 16.42; 95% CI, 4.11 to 65.54; P<0.001), which resulted in higher non-relapse mortality (NRM) (HR, 5.16; 95% CI, 2.62 to 10.15; P<0.001) and worse overall survival (HR, 2.81; 95% CI, 1.66 to 4.78; P<0.001). Similarly, a maximum body temperature≥40.5°C was significantly associated with lower neutrophil recovery (HR, 0.51; 95% CI, 0.33 to 0.79; P=0.002), lower platelet recovery (HR, 0.55; 95% CI, 0.38 to 0.79; P=0.001), higher incidence of grades III to IV acute GVHD (HR, 2.93; 95% CI, 1.24 to 6.88; P=0.013), and extensive chronic GVHD (HR, 2.47; 95% CI, 1.22 to 4.97; P=0.011), which resulted in higher NRM (HR, 3.43; 95% CI, 1.53 to 7.67; P=0.002). CONCLUSION Maximum CRP level and maximum body temperature during neutropenia were significantly associated with lower hematopoietic recovery and higher NRM following single-unit CBT in adults. Further studies are warranted to explore early intervention strategies aimed at preventing severe inflammation and improving post-transplant outcomes in single-unit CBT.