Alterations in spleen growth and sequestering function in animals receiving trypan blue.

Trypan-blue-induced alterations in spleen size and sequestering activity were studied in rats as possible experimental counterparts of the splenic enlargement and dysfunction associated with lymphomas in man. The spleen was examined radiographically and histologically following the i.v. administration of tantalum particles in animals receiving 4-17 s.c. injections of trypan blue at fort-nightly intervals and in control animals. Spleen size and sequestering activity increased in all rats receiving trypan blue. Histological studies demonstrated that an increase in mechanical filtration was responsible for the dysfunction. Tantalum was deposited extracellularly in perifollicular marginal zones in both experimental and control animals but these areas were much more prominent in experimental animals, contained more tantalum and retained the particles for longer periods.