Granulomatous interstitial pneumonia in a miniature swine associated with repeated intravenous injections of Tc-99m human serum albumin: concise communication.

Albumin lung-scanning agents have a proven high degree of safety, with the only contraindication to their use being allergic hypersensitivity. We have used these agents to investigate the physiologic effects of high Gz acceleratory forces on pulmonary perfusion using the miniature swine. Multiple doses of human macroaggregated albumin and human-albumin microspheres were given to a miniature swine at various levels of centrifugal acceleration over a 6-wk period. The dosages given were the same per kilogram as those used for routine clinical human studies. The animal subsequently died from a severe granulomatous interstitial pneumonia. The granulomatous lesions suggest that the pathogenesis may have involved a cell-mediated delayed hypersensitivity. This interstitial pneumonia may represent the end point in a chronic hypersensitivity response to the human-albumin lung-scanning agents.