Value of eosinophil count in bronchoalveolar lavage fluid for diagnosis of allergic bronchopulmonary aspergillosis: A case report

BACKGROUND: An immediate hypersensitive immune response to Aspergillus fumigatus antigens is one of the main characteristic features of allergic bronchopulmonary aspergillosis (ABPA). As ABPA is an allergic respiratory disease, immunoglobulin E and peripheral-blood eosinophilia have been used as diagnostic indicators. However, eosinophilia in bronchoalveolar lavage fluid (BALF) has not been considered in the diagnostic criteria for ABPA. CASE SUMMARY: We present a case of ABPA in which the eosinophil count in peripheral blood was not increased, whereas the eosinophil percentage in BALF reached 60%. After antifungal and hormone therapy, imaging revealed very good resolution of lung infiltration. CONCLUSION: The value of the eosinophil count in BALF for the diagnosis of ABPA is worthy of the clinician's attention, especially when the patient’s clinical features lack specificity and the diagnostic parameters are negative.