Hyperacute rejection and humoral rejection are antibody-mediated forms of rejection that are recognized in other solid organ transplants but that are not yet well defined in the setting of lung transplantation.

Cases reported as hyperacute rejection of lung transplants are rare and potentially fatal, occuring minutes to hours post-transplant. Hyperacute rejection is believed to be the result of antibody-mediated rejection due to antidonor antibodies developing in the recipient before transplantation. Immunoglobulin (IgG) and complent deposition occur in the alveolar septa. Pleural effusion, pulmonary edema, and progressive respiratory failure are the clinical presentation. The stages of humoral rejection due to circulating antibodies in lung transplant are not well characterized. Positive immunofluorescent staining for C4d deposition is variably present in the alveolar sepata and airway walls in patients who develop acute rejection and bronchiolitis obliterans syndrome, respectively.