Pulmonary hyalinosis in captive sugar gliders ( Petaurus breviceps)

Pulmonary hyalinosis is an idiopathic, typically incidental lesion of old dogs, characterized by multifocal aggregates of epithelioid and multinucleate macrophages that surround periodic acid-Schiff (PAS)-positive hyaline material in airways. Lung lesions resembling pulmonary hyalinosis were observed in 6 captive adult sugar gliders ( Petaurus breviceps; 5 females and 1 male) in a retrospective review of 18 autopsied animals. Clinical signs for 3 of the sugar gliders included lethargy, tachypnea, and dyspnea. At autopsy, 5 of 6 animals had comorbid lesions that were the primary cause of death. Gross pulmonary lesions were characterized by mildly firm, discolored, vaguely nodular areas of parenchyma. Histologic examination of the lung revealed granulomatous inflammation with intracellular and extracellular amphophilic hyaline bodies within alveoli and airways. Hyaline bodies were positive for PAS and oil red O staining, blue via crystal violet staining, and displayed birefringence under polarized light, similar to findings in dogs with pulmonary hyalinosis.

Hypothesis: hemolytic transfusion reactions represent an alternative type of anaphylaxis

Classical anaphylaxis is the most severe, and potentially fatal, type of allergic reaction, manifested by hypotension, bronchoconstriction, and vascular permeability. Similarly, a hemolytic transfusion reaction (HTR) is the most feared consequence of blood transfusion. Evidence for the existence of an alternative, IgG-mediated pathway of anaphylaxis may be relevant for explaining the pathophysiology of IgG-mediated-HTRs. The purpose of this review is to summarize the evidence for this alternative pathway of anaphylaxis and to present the hypothesis that an IgG-mediated HTR is one example of this type of anaphylaxis.