Cytochemistry of hairy cells.

Abstract

The peripheral blood of 24 patients with bone marrow biopsy-proven hairy cell leukemia was examined with histochemical methods. Periodic acid-Schiff, acid phosphatase, acid phosphatase with tartrate, alpha naphthyl butyrate esterase, alpha naphthyl acetate esterase, and alpha naphthyl acetate esterase with sodium fluoride inhibition were among the reactions utilized. Reactivity was graded on a scale of 0 to +++. All patients had circulating hairy cells, ranging from 2 to 88% of the leukocyte count. Sequential studies (2 – 7 times) were performed in 9 of the patients. A finely granular, ± to ++ reaction product with periodic acid-Schiff (PAS) was present in 22 patients; in 3, however, the PAS was negative at one time in sequential studies. Acid phosphatase activity was present in more than 50% of the hairy cells in 21 patients; in only one was the reaction present in less than 25% of the leukemia cells. The reaction consisted of formation of granules which were small to medium in size with diffuse and irregular cytoplasmic distribution. Tartrate resistant acid phosphatase activity was present in 1 – 100% of the hairy cells in 23 of the 24 patients. One patient with 35% circulating cells showed acid phosphatase reactivity in 58% of these, but tartrate-resistant acid phosphatase reactivity was totally absent; the intensity of these two reactions varied between patients and within the same patient. Alpha naphthyl butyrate esterase reactivity ranged from ± to + in 16 of the 20 patients examined. In 19 of 20 patients, the alpha naphthyl acetate esterase reaction was ± to ++ positive, consisting of diffusely scattered granules in at least a few and, in some cases, in as many as 95% of the cells. This activity was inhibited by sodium fluoride in 16 of 19 patients. These findings are compared to those in 17 patients with various lymphoproliferative and myeloproliferative disorders who were studied by the same methods. Our results indicate that the cytochemical properties of hairy cells differ from those of any established cell group.