Pulmonary pathology of rapidly fatal transfusion-related acute lung injury reveals minimal evidence of diffuse alveolar damage or alveolar granulocyte infiltration

Abstract

Background: Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-associated death in the United States. Its diagnosis is based on clinical and radiographic changes that are indistinguishable from acute lung injury/acute respiratory distress syndrome (ALI/ARDS). TRALI is presumed to be a form of ALI/ARDS; however, it differs in its triggering events and associated mortality. Two cases of rapidly fatal TRALI in which the postmortem pathology differed from that classically associated with ALI/ARDS are reported.

Case report: Two men (aged 75 and 83 years) developed rapidly fatal TRALI after receiving single units of plasma for correction of elevated international normalized ratios. The donors were found to have white blood cell (WBC) antibodies that included specificities for WBC antigens expressed by the recipient (HLA Class I or Class II and/or HNA-3b [5a] antibody). Autopsy findings in both patients revealed bilateral pleural effusions and extensive patchy areas of alveoli filled with proteinaceous fluid. The pulmonary capillaries were congested with red blood cells and WBCs. Diffuse alveolar damage, including interstitial inflammation, intraalveolar granulocyte infiltration, and hyaline membrane formation, were not identified in either case.

Conclusion: In both patients the clinical and radiographic findings were indicative of TRALI and indistinguishable from ALI/ARDS. However, diffuse alveolar damage, the classic autopsy finding in ARDS, was not identified, suggesting a different pathogenesis. Further studies are needed on the role of polymorphonuclear cells in the initiating events of TRALI that lead to ALI and the resulting breakdown of the permeability integrity of the alveolar walls.