Small inclusions in the cytoplasm of leukocytes in LE cell tests.

Small homogeneous basophilic and eosinophilic particles varying in size from 0.7 to 3.0 micra were seen in cytoplasm of monocytes and polymorphonuclear cells of leukocytes in LE cell tests. The aim of this investigation was to determine their frequency and diagnostic significance. Inclusions were found in one-third of LE cell tests on patients with rheumatic diseases and were not observed in normals. In 19.1% of 161 patients with SLE, they were present before LE cells were found. Sixty-eight% of patients who had particles had SLE, 8% had rheumatoid arthritis with LE cells, and 3% had nonrheumatic diseases.