Effects of prednisolone and anti-macrophage serum on the development of carditis and arthritis due to group A hemolytic streptococci in mice.

The effects of prednisolone and anti-macrophage serum (AMS) on the development of cardiac and articular lesions were compared in experimentally infected mice with group A hemolytic streptococci. The predonine-treated mice had a higher mortality rate and greater abscess formation than in the AMS-treated mice. The predonine-treated group had a higher incidence of cardiac lesions due to chronic pericarditis and chronic myocarditis, and the former was particularly frequent. Pathologic findings seen in the AMS-treated mice were those of acute pancarditis. The AMS-treated animals also had lesions of subacute or chronic arthritis, whereas articular lesions encountered in the Predonine-administered group were frequently those of chronic periarthritis and, in no instance, synovitis. These data indicated that treatment with AMS is more effective than that with prednisolone to experimentally induced rheumatic fever in laboratory animals.