Invasive fusariosis after allogeneic hematopoietic cell transplantation: clinical features and prognostic value of serum β-D-glucan in a nationwide Japanese registry study

Invasive fusariosis is a rare but often fatal infection in immunocompromised patients. However, data in allogeneic hematopoietic cell transplantation (HCT) are limited. Using a nationwide Japanese transplant registry database, we identified patients who underwent allogeneic HCT between 2008 and 2021 and subsequently developed invasive fusariosis. We conducted questionnaire survey to characterize invasive fusariosis and identify factors associated with early mortality. Thirty-one patients were included. Invasive fusariosis developed at a median of 24 days after HCT. Neutropenia was present in 23 patients (74.2%), and corticosteroids were administered to 23 patients (74.2%). The most commonly involved sites were the bloodstream (71.0%), skin (54.8%), and the respiratory tract (35.5%). Serum (1→3)-β-D-glucan (BDG) was positive in 26 of 31 patients (83.9%) within 2 weeks after diagnosis, whereas BDG positivity preceded the diagnosis in only 15 of 29 evaluable patients (51.7%). Twenty-two (71.0%) died within 30 days after the diagnosis. BDG value normalized to the upper limit of normal (BDG/ULN) within 1 week before diagnosis was significantly lower in 30-day survivors than in non-survivors (median, survivor 0.55 vs. non-survivor 2.94). A pre-diagnostic BDG/ULN of 1.27 predicted 30-day mortality with a sensitivity of 85.7% and a specificity of 81.0%. Among 23 patients who developed invasive fusariosis during neutropenia, all seven 30-day survivors achieved neutrophil recovery, whereas none of the non-survivors did. In conclusion, invasive fusariosis after allogeneic HCT was associated with extremely poor outcomes, particularly in patients with persistent neutropenia. Elevated BDG levels around the time of diagnosis were strongly associated with early mortality.