Iron Levels in Bronchoalveolar Lavage Fluid of Hematological Patients with Suspected Invasive Pulmonary Aspergillosis and their Association with 12-week Mortality: A Retrospective Cohort Study

ObjectivesAccuracy of diagnostic tests for invasive pulmonary aspergillosis (IPA) using bronchoalveolar lavage fluid (BALF) remains suboptimal. Elevated tissue iron in lung transplant and murine models is linked to invasive Aspergillus growth. This study examines the correlation between BALF iron levels, IPA, and 12-week mortality.MethodsWe conducted a retrospective cohort study at a tertiary care center, including 100 BALF samples from patients with hematological malignancies and suspected IPA between 2014 and 2019. Data regarding iron concentrations, mycological tests, and 12-week mortality were analyzed.ResultsHigher iron levels correlated with a greater likelihood of IPA based on EORTC/MSGERC 2020 definitions (p = 0.038). The ROC area was 0.648 (95% CI 0.531-0.764), with an optimal cut-off of 0.75 mu mol/L to distinguish cases (27 probable and 0 proven IPA) from controls (56 possible and 17 no IPA), with sensitivity 76.9% and specificity 47.3%. Iron levels were positively correlated with higher fungal loads (galactomannan: Spearman's rho 0.323, p = 0.001; Aspergillus PCR Ct-values: rho - 0.602, p = 0.002). A trend toward higher 12-week mortality was observed in patients with iron concentrations >= 0.90 mu mol/L compared to lower levels (p = 0.086).ConclusionsBALF iron concentrations were highest in those with probable IPA, followed by possible IPA and lowest in patients without IPA, with higher iron levels also correlating with fungal loads and potentially with 12-week mortality. However, given the various potential confounding factors, further prospective studies are essential to establish causality. These findings warrant additional investigation into BALF iron as a potential marker for 12-week survival, but validation is necessary before considering it as a supplementary marker in the current EORTC/MSGERC 2020 classification for probable or possible IPA.