THE CD4 CD8 RATIO IN BAL FLUID IS HIGHLY VARIABLE IN SARCOIDOSIS/

Patients with pulmonary sarcoidosis frequently have increased numbers of lymphocytes and a high ratio of CD4+ to CD8+ T-lymphocytes (CD4/CD8 ratio) in bronchoalveolar lavage (BAL) fluid, Some investigators have suggested that these parameters can be used to distinguish sarcoidosi s from other types of interstitial lung disease with a high degree of reliability. However, we hypothesized that the BAL CD4/CD8 ratio measu red during the initial diagnostic evaluation of patients with biopsy-p roven sarcoidosis is highly variable, BAL lymphocytes were analysed vi a flow cytometry to determine the CD4/CD8 ratio in a population of 86 patients with histological and clinical evidence of sarcoidosis, who u nderwent BAL as part of their initial diagnostic evaluation, In these patients, the CD4/CD8 ratio ranged 0.5-37.3, with a median value of 3. 35 (mean 6.49), The CD4/CD8 ratio was greater than 4 in only 36 (42%) subjects, Ten patients (12%) had a CD4/CD8 ratio less than 1, The dist ribution of CD4/CD8 ratios was similar in the presence or absence of B AL lymphocytosis. In conclusion, the CD4/CD8 ratio in bronchoalveolar lavage fluid is highly variable in biopsy-proven sarcoidosis, Bronchoa lveolar lavage lymphocyte subset determination is a diagnostic test wi th low sensitivity for this disease.