Metallic tin-induced lymphadenopathy in rat strains and hybrids.

Metallic tin powder, injected into Lewis rats obtained from three different sources, caused enlargement of the regional draining lymph nodes. The histopathology featured epithelioid cell granulomas around phagocytosed particles of tin and an intense hyperplasia of plasma cells. The same material injected into August rats enlarged the lymph nodes but the enlargement was caused by granulomas without a major concomitant plasma cell response. In most other strains, tin produced less lymph node enlargement and the plasma cell response was minimal. However, F1 hybrids of Lewis rats with either the August, Brown-Norway (BN), or Dark Agouti (DA) strains developed plasma cell hyperplasia similar to that seen in the parental Lewis strain. The response to tin was the same whether the tin was injected into the feet or into the peritoneal cavity. Thus, the lymph node response to metallic tin varied from a slight, banal response to insoluble foreign particles, to an exuberant granulomatous hyperplasia, to an intense plasmacellular hyperplasia, depending on the genetic characteristics of the subjects.