Sarcoid-like lymphocytosis of the lower respiratory tract in patients with active Crohn's disease.

To re-evaluate the relationship between Crohn's disease and sarcoidosis, we compared the numbers and types of cells recovered by bronchoalveolar lavage from normal volunteers and patients with Crohn's disease, with other forms of inflammatory bowel disease, and with sarcoidosis. Patients with Crohn's disease, but not patients with other inflammatory bowel disorders, had an increase in the number of T lymphocytes on the surface of the lower respiratory tract similar to that seen in patients with sarcoidosis. As in sarcoidosis, this lymphocytosis results from an expansion of the T4+ T-lymphocyte subset, is characteristic of patients with active disease only, and is not associated with similar abnormalities in the peripheral blood. Thus, patients with apparently localized Crohn's disease have sarcoid-like lymphocytosis of the lower respiratory tract, a finding that emphasizes the systemic nature of Crohn's disease and the disorder's close relationship to sarcoidosis.