Effect of inoculation of sarcoid tissue into athymic (nude) mice

Previous reports have suggested that the inoculation of sterile homogenates of human sarcoidosis tissue produce pathological changes or death in T cell deficient mice, while other reports have challenged these results. Because of the importance of this point, the potential infectiousness of human sarcoid tissue was investigated using athymic (nude) mice. Eight tissue specimens were obtained from patients with sarcoidosis and inoculated once into a total of sixty-two nude mice. These experiments were conducted over a period of two years. The tissue specimens inoculated included biopsies of lung, lymph node and muscle. A non-tissue buffer was used as a sham control and inoculated into ten nude mice. Of the eight tissue specimens, six were found to contain non-caseating granulomas consistent with sarcoidosis. Only one of these six specimens induced significant pathological changes when injected into nude mice: two mice developed reticulum cell sarcoma and one developed membranous glomerulonephritis. Five inoculations of sarcoid tissue into a new athymic mouse colony housed in resterilized cages produced no detectable pathology. Two different tissue specimens not containing sarcoid granulomas were inoculated into two groups of nude mice. Both of these specimens induced pathological changes. One mouse developed a reticulum cell sarcoma, one developed lymphoma and one developed interstitial nephritis. A saline control inoculation produced no pathology in any mice. Mortality rates were similar in sarcoid inoculated, normal tissue inoculated and saline inoculated mice. These findings suggest that if sarcoidosis has an infectious etiology, the responsible agent is not one that easily infects athymic mice.(ABSTRACT TRUNCATED AT 250 WORDS)