Biphasic trafficking of lymphocytes during acute inflammation. (A-C) Patients undergoing chronic ambulatory peritoneal dialysis and who developed peritonitis that resolved were found to have lymphocytes at the time of recovery of clinical symptoms. Pursuing this observation in murine zymosan-induced peritonitis (D), T and B cells native to the naive peritoneal cavity were found to disappear within hours of stimulus injection. Once inflammation resolves, lymphocytes repopulate the peritoneum but comprise more (E-J) CD4⁺/CD25 and γ/δ T cells as well as NK cells, than is present in the naive cavity (0 hours) as well as (K) MAC-1⁺ B cells. (L) Experimentally enhancing the severity of the inflammatory response within the peritoneum by injecting 3 separate doses of zymosan (0.1, 1.0, and 10 mg) prolonged resolution and delayed lymphocyte repopulation (72 hours), suggesting that lymphocytes repopulate only after resolution occurs. n = 6 to 8 animals per group; *P ≤ .05; **P ≤ .01, as determined by analysis of variance (ANOVA), followed by Bonferroni t test, with data expressed as means plus or minus SEM.