Do lymphocytes play a pro-inflammatory role in any pharmacological type of rat paw edema?

1. The hypothesis of a pro-inflammatory activity in lymphocytes related to the development of nonimmune acute inflammation was tested in leucopenic rats injected subcutaneously with various stimuli representing different pharmacological classes of paw edema-inducing agents into the subplantar area of one of the hind paws. 2. Amethopterin-induced leucopenia rendered animals hyporeactive to carrageenin and trypsin, but not to kaolin or dextran. 3. Administration of splenic lymphocytes to leucopenic rats to correct lymphopenia partially restored the inhibited responses to carrageenin and the early phase of responses to trypsin. 4. These results suggest that lymphocytes may play a pro-inflammatory role in nonimmune acute inflammation, which is more demonstrable in some pharmacological classes of paw edema than in others.