Trauma and inflammation modulate lymphocyte localization in vivo: Quantitation of tissue entry and retention using indium-111-labeled lymphocytes

Objective: Determine the in vivo localization pattern of indium-111-labeled lymphocytes after a standardized extremity injury or standardized laparoto my and after sterile inflammation of the central nervous system. Design: Prospective animal study with concurrent controls. Setting: Animal research laboratory. Subjects: Male Lewis rats weighing 150-175 g. Interventions: Indium-111-labeled splenic lymphocytes were injected into an imals after a standardized hind limb trauma or laparotomy and after inducti on of sterile central nervous system inflammation. Measurements and Main Results: Lymphoid and non-lymphoid organs were remove d at fixed intervals after lymphocyte injection acid the proportion of inje cted lymphocytes/gram of tissue was determined using a quantitative radionu clide calculation. Results from treated animals were compared with results from untreated control animals. Muscle injury caused early localization of lymphocytes to injured hind limbs, liver, and spleen compared with controls , whereas laparotomy decreased lymphocyte localization in the thymus and co lon. Encephalitis increased localization to the central nervous system with no effect on other tissues, Conclusions: These results identify a sensitive method to track in vivo leu kocyte localization and specifically demonstrate that lymphocyte localizati on is altered in both traumatic and nontraumatic models of inflammation.