Phagocytic capacity of hairy cells from seventeen patients.

Hairy cells from 17 patients diagnosed as having hairy cell leukemia were evaluated with both light and transmission electron microscopy for their capacity to phagocytose zymosan, latex, Staphylococcus aureus, and Pseudomonas aeruginosa. The hairy cells of fifteen of the sixteen patients which were tested with latex showed significant phagocytosis. Cells of thirteen of the seventeen patients showed phagocytosis of staphylococcus; six of the seventeen, phagocytosis of zymosan; and four of seventeen, phagocytosis of pseudomonas. Of the four substances tested, staphylococcus and latex yielded consistently higher numbers of ingested particles per hairy cell than did zymosan or pseudomonas. Observation of serial sections by transmission electron microscopy revealed that each type of particle is fully enclosed within the cytoplasm of the hairy cell. A Lysostaphin assay performed on the hairy cells of two patients showed that lysis of the phagocytosed particles by the hairy cell differs significantly from that by normal mononuclear cells. The results support our earlier study which suggested that hairy cells have phagocytic capabilities which differ not only among patients, but also within a single patient over time.