Bronchoalveolar Lavage Fluid Cellularity Reflects Peripheral Cytopenias and Fungal Burden but Not Short-Term Outcomes in Invasive Pulmonary Aspergillosis.

We characterized leukocyte profiles in bronchoalveolar lavage fluid (BALF) of 63 patients with hematologic malignancy and culture-documented invasive pulmonary aspergillosis and evaluated associations with peripheral blood leukocyte counts, Aspergillus burden, respiratory coinfections, and clinical outcomes. BALF cellularity mirrored peripheral cytopenias yet increased with higher Aspergillus burden and respiratory coinfections, consistent with both systemic immune availability and local inflammatory stimuli. However, BALF cellularity was not independently associated with 42-day mortality, which was driven by persistent neutropenia and critical illness. These findings suggest BALF cellularity may not be an independent determinant of short-term outcomes but rather reflects underlying host and disease context.