One of the characteristic features of the lupus syndrome in humans and mice is the organ-specific accumulation of leukocytes within a variety of different tissues; however, the etiology of this phenomenon remains unclear. The work presented here determined the role of intercellular adhesion molecule (ICAM)-1 in the development of pulmonary leukocyte accumulation by generating MRL/MpJ-Faslpr mice that are genetically deficient in this critical adhesion molecule. Interestingly, these MRL/MpJ-Faslpr ICAM-1 knockout mice exhibit prolonged survival times compared to littermates expressing ICAM-1. We have determined that lack of ICAM-1 completely abrogates the development of pulmonary inflammation but does not prevent the development of autoantibodies, lymphadenopathy, and glomerulonephritis. Furthermore, the lack of pulmonary inflammation was found to be due to decreased migration of leukocytes to the lung rather than decreased in situ proliferation of cells.