C62-24 Follicular Bronchiolitis Following Liver Transplant in a Young Child

Abstract Introduction Inflammatory bronchiolitis following non-lung solid organ transplant (SOT) is rare but has been described in case reports. Herein, we present a child with clinical and radiologic evidence of small airways disease and biopsy evidence of follicular bronchiolitis following liver transplant. Case Report A six-year-old girl was referred for intermittent increased work of breathing, cough and exertional dyspnea 3 months following cadaveric liver transplant for failed Kasai for biliary atresia. Chest CT demonstrated diffuse bilateral mosaicism and bronchial wall thickening consistent with airways inflammation and gas trapping (Figure 1A). Spirometry attempts were unsuccessful, but multiple breath nitrogen washout demonstrated an elevated lung clearance index (LCI) at 10.8 (normal 7.1). Flexible bronchoscopy was macroscopically unremarkable. Bronchoalveolar lavage fluid analysis demonstrated neutrophilic alveolitis on cell count (80% neutrophils) and cytopathology. Extensive microbiological testing failed to identify evidence of bacterial, viral or fungal pathogens. Surgical lung biopsy demonstrated follicular bronchiolitis with mixed population lymphocytic infiltrates of the small airways and no evidence of fibrosis or luminal obliteration (Figure 1B-D). Chimerism analysis performed on donor and recipient peripheral blood, and lung tissue, failed to reveal donor derived cells. She commenced treatment with monthly pulse methylprednisolone (30 mg/kg/day for 3 days) for 3 months, daily oral prednisone (1 mg/kg/day), thrice weekly azithromycin and twice daily inhaled fluticasone/salmeterol. She demonstrated clinical improvement following the second corticosteroid pulse, coinciding with normalization of LCI to 6.6. Her symptoms completely resolved by 3 months following the final methylprednisolone pulse. Prednisone was weaned and ceased 6 months following the final pulse of methylprednisolone. She remained clinically well with a normal LCI at 3 months following complete cessation of corticosteroids. Azithromycin was ceased with a plan for future cessation of fluticasone/salmeterol. Novelty & Importance Our patient presented 3 months after SOT with clinical and radiographic changes consistent with small airways disease, and a pathological diagnosis of follicular bronchiolitis (FB). FB is a pathological diagnosis characterized by proliferation of bronchus-associated lymphoid tissue with resultant peribronchial follicles. It is associated with multiple etiologies, including infection, autoimmune disease and immunodeficiency. However, it has also been described in lung transplant recipients presenting with bronchiolitis obliterans syndrome (BOS). To our knowledge, this is the first description of FB following pediatric non-lung SOT. Despite extensive testing, including molecular chimerism testing, no clear cause of FB was identified. She responded well to standard BOS treatment with corticosteroids, azithromycin and fluticasone/salmeterol. This case supports investigation and treatment for BOS in this setting. This abstract is funded by: None