Anti-Aspergillus immunoglobulin-G testing in serum of hematopoietic stem cell transplant recipients

Pulmonary invasive aspergillosis (IA) is a major clinical problem in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Acquisition of IA during allo-HSCT by inhalation of spores is the rationale for the widespread use of air filtration systems. Recent data suggest that activation of fungal growth in already colonized patients is a relevant factor, and a recent study found a positive correlation of serum immunoglobulin responses against purified recombinant Aspergillus fumigatus proteins before allo-HSCT with the incidence of IA after allo-HSCT.

To investigate the clinical utility of this approach, we performed a prospective study. We used a commercially available and standardized assay for detection of anti-Aspergillus immunoglobulin-G (aA-IgG) in serum (Platelia(™) Aspergillus IgG) that has previously demonstrated high sensitivity and specificity.

In a cohort of 104 allo-HSCT recipients, we measured aA-IgG and Aspergillus antigen serum levels before allo-HSCT, and weekly during hospital stay. Overall prevalence of possible, probable, and proven IA during hospital stay was 10%, 6%, and 0%. We found no correlation between aA-IgG levels before allo-HSCT, or after allo-HSCT, and the prevalence of IA during hospital stay. Furthermore, median aA-IgG levels did not differ between patients with history of probable or proven IA, as compared to patients without history of IA.

Taken together, our data argue against the clinical utility of measuring aA-IgG levels for diagnosis or prediction of IA in patients undergoing allo-HSCT.