Abstract
Introduction: Ferritin is an acute phase reactant commonly elevated in response to infections, inflammation, liver disease, and malignancy. However, the significance of persistently elevated serum ferritin levels in lung transplant patients is poorly understood. In this case series, we present our experience with elevated ferritin levels in 3 lung transplant recipients. Case Descriptions: We report three patients who underwent bilateral lung transplantation at our center, with a median age of 67 years. After transplant, all patients displayed persistently elevated serum ferritin levels, with a median of 988 µg/L, peaking at 6147 µg/L. Indications for lung transplant included chronic obstructive pulmonary disease, pulmonary fibrosis, and combined pulmonary fibrosis and emphysema. Patient 1 experienced a progressive increase in ferritin levels (266-6174 µg/L) and required 14 hospital admissions for pneumonia, pleural effusion, and infections with Streptococcus anginosus, Aspergillus, and Pseudomonas. Patient 2, who had the highest recorded ferritin level of 9228 µg/L, was diagnosed before transplant with myelodysplastic syndrome that progressed to acute myeloid leukemia 10 months after transplant. This patient died one year after transplant and had persistent Staphylococcus aureus bacteremia and pneumonia. Patient 3 had an elevated pretransplant ferritin level of 1890 µg/L, which remained high after transplant at 1468 µg/L. Notably, this patient has not required hospital readmission since their transplant in February 2024 and continues to be closely monitored. Discussion: Our cases highlight a novel finding: persistently elevated ferritin levels without an identifiable cause in lung transplant recipients. Ferritin is a known marker of inflammation, and ferritin levels and transferrin saturation are predictors of body iron stores. Iron overload has a significant role in the pathogenesis of various infections through free radical-induced tissue damage. Elevated ferritin levels have been associated with a higher risk of morbidity and mortality after stem cell transplantation, and with worse outcomes in patients with hematological or lung malignancies. However, its significance in this immunocompromised transplant population remains unclear and may extend beyond infection or iron overload. We hypothesize that elevated ferritin in these patients may reflect a complex immunological or metabolic response to transplantation. This is the first report to explore the significance of elevated ferritin and its prognostic implications in transplant patients. We suggest that serum ferritin be measured in routine clinical evaluation and follow-up of lung transplant recipients, and high levels should prompt further investigations for underlying pathology.