Peripheral blood eosinophilia in association with sarcoidosis

To review retrospectively our experience with peripheral blood eosinophilia (PBE) in sarcoidosis and to analyze histologically lung biopsy specimens for the presence of lung tissue eosinophils.

We reviewed 140 cases of sarcoidosis diagnosed between May 1975 and January 1998. Ninety-five patients (66.3% women; 70.5% African American; mean age, 35.9 years) met the inclusion criteria. Transbronchial biopsy specimens from 82 patients were divided into 4 morphologic compartments: parenchyma, bronchial wall, parenchymal granulomas, and bronchial wall granulomas. Within compartments, up to 10 high-power fields were scored semiquantitatively for eosinophils, from 0 (none) to 4+ (numerous).

Thirty-nine patients (41%) had PBE. Four had PBE greater than 10%. The highest eosinophil count (21%) occurred in 1 patient. Sixty-five (79%) of 82 patients had no or few (1+) eosinophils in lung tissue; 17 patients had eosinophils scored as 2+ or higher. There was no correlation between peripheral blood eosinophil count and presence of eosinophils in transbronchial biopsy specimens. Eosinophils were least conspicuous in parenchyma but evenly distributed in bronchial wall and parenchymal and bronchial wall granulomas.

Peripheral blood eosinophilia occurs frequently in sarcoidosis. However, there appears to be no association between peripheral blood eosinophil count and presence of lung tissue eosinophils. Whether eosinophils participate in the pathogenesis of sarcoidosis requires further study.