Blinatumomab-Induced Pneumonitis in a Pediatric Case in B-cell Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is common in children, with advancements in its treatment, particularly with the of new immunotherapeutics. Blinatumomab, a bispecific T-cell-engaging antibody, option for relapsed/refractory ALL. Although recent studies focused on the safety and side effect profile, its association with interstitial lung disease in children has been reported very rarely. Here, we present a case with pulmonary symptoms suggesting drug-related interstitial lung disease.A 4.5-year-old boy, diagnosed with relapsed refractory B-cell ALL, initiated Blinatumomab at the age of 6. A few days after Blinatumomab, he developed shortness of breath, dyspnea, and hypoxia. X-ray revealed bilateral paracardiac reticulonodular infiltrations. Despite intravenous antibiotic, antifungal, and inhaler treatments, the patient showed no improvement. Subsequent chest CT demonstrated extensive interlobular septal thickening, patchy consolidation, and scattered bilateral ground-glass opacities revealed interstitial lung disease. Clinical and imaging deterioration persisted. The patient's pulmonary findings significantly responded to steroid treatment, leading to an obvious regression of interlobular septal thickening, and the oxygen demand returned to baseline. The onset of symptoms shortly after drug administration, the presence of septal thickening on CT suggestive of interstitial lung disease, and the rapid response to steroids imply a potential association with drug-induced pneumonitis. In patients receiving immunotherapy, after excluding infectious causes, it is important to consider drug-related interstitial lung diseases when both radiological and clinical features indicate such conditions.