Search

Normal human blood cells contain esterases which hydrolyze alpha-naphthyl acetate (alpha NA). Purified preparations of these cells were investigated by polyacrylamide gradient gel electrophoresis at pH 9.0 and subsequent staining of gels for esterase activity. Extractable alpha NA esterase was separated according to molecular weight. alpha NA esterase with molecular weight of 55 000 was observed only in lymphocytes and red cells. Lymphocytes from patients with B-cell chronic lymphocytic leukemia (B-CLL) showed alpha NA esterase with molecular weight of 45 000 instead of 55 000. Esterases with molecular weights of 60 000 and 70 000 were detected in granulocytes monocytes and red cells. Only platelets and red cells exhibited alpha NA esterase with molecular weight of 80 000. alpha NA esterases with molecular weight of 290 000 could be demonstrated in granulocytes and red cells. All blood cells contained esterase with molecular weight of 360 000. alpha NA esterase with molecular weight of 390 000 was detected only in red cells. In all blood cells (without lymphocytes) esterase with molecular weight of 500 000 was demonstrated. Only the enzyme in monocytes, granulocytes and red cells was sensitive to fluoride inhibition.

The alpha naphthyl acetate esterase (ANAE) cytochemical staining patterns were examined in 40 cases of acute myeloblastic leukaemia (AML: FAB groups M1 and M2) classified by morphological and immunological criteria. The blast cells in most cases (62%) were ANAE-negative with the remainder showing diffuse, granular or focal reactions of varying intensity. The nature of cytoplasmic ANAE enzymes was further characterised in 20 cases by isoelectrophoretic analysis of ANAE isoenzymes. The results suggest that the presence of significant cytoplasmic ANAE reactivity in leukaemic myeloblasts is not due to the presence of monocyte-associated isoenzymes, in otherwise well-defined myeloblasts, but may reflect abnormally increased synthesis or atypical localisation of normally-occurring ANAE isoenzymes. In particular, the results of this study indicate the lack of discriminatory value of ANAE cytochemistry in the differentiation of AML from other acute leukaemias of non-monocytic type.

The activity of alpha-naphthyl acetate esterase at an acid pH (ANAE) was investigated in 10 cases of hairy cell leukemia. All 10 cases, including two cases with only a few tartrate-resistant acid phosphatase-reactive cells, revealed a moderate or strong ANAE reaction. There was a characteristic pattern of activity consisting of small, medium-size, or large distinct granules often distributed in a semicircle in the cytoplasm, but sparing the nucleus of hairy cells. This reaction pattern was not found in T cells, T cell-derived leukemias, normal B cells, a number of B-cell lymphomas, myeloid cells, myeloid leukemias (including monocyte-derived leukemias), reticulum cell sarcoma, or malignant reticulosis. The cells from some B-cell lymphomas and plasmacytoma showed a relatively homogeneous pattern of fine or moderately coarse ANAE-positive granules that was similar to that of hairy cells only in some cases of plasmacytoma. Thus, fine to coarse granular ANAE reactivity is characteristic of hairy cells and is of potential diagnostic value for hairy cell leukemia.

In the September 1979 issue of your distinguished journal Tolksdorf and Stein described a characteristic staining pattern of hairy cells with the acid alpha naphthyl acetate esterase (ANAE) staining technique in 10 cases of hairy cell leukemia (HCL).They showed that most of the hairy cells contain very heavy granules that are concentrated around the nucleus and in many cases form a semicircular patternl We had the opportunity of executing the ANAE staining in another case of HCL. In the peripheral blood of this case (cytospin smears of Fiqoll-Isopaque interphase mononuclears) we found 57% of hairy cells positive for tartrate-resistant acid phosphatase (Yam and al., 1971). We found the same heavy granular reaction pattern of the hairy cells for this kind of nonspecific esterase as described by Tolksdorf and Stein. The technique we used was exactly the same as described by Mueller and al. (1975) in their original paper: fixation during 10 rain in cold Baker's formalin pH = 6.7, no airdrying of the smears, and a long incubation time of 21 h. We think that the original technique gives a more intensive reaction product due to the longer incubation time and a better preservation of morphology due to fixation of the smears. Some authors do not like airdrying of the smears because of enzyme activity loss (Kulenkampff 1976; Knowless 1978, pers. observ.). In our experience diffusion artefacts caused by the long incubation time are not very pronounced and certainly do not disturb interpretation. In our case the cytospin-smears stained for ANAE rendered the following results: 71% of lymphoid cells: most of them contained heavy granular deposits, in many cases semicircular around the nucleus. Some other, morphologically normal lymphoid cells in this category (perhaps non-T lymphocytes) contained only a few distinct medium-sized granules. Twenty-nine per cent of lymphoid cells (small lymphocytes) showed a heavy dot-like reaction as described for Tlymphocytes, thymocytes (Kulenkampff 1977; Knowless 1978) or T-helper lymphocytes (Grossi 1978). Cytospin preparations of the mononuelear fraction of the peripheral blood of this patient were also stained for beta-glucuronidase (/3-Gluc.). Different reaction patterns were observed in the lymphoid cells: Seventy-four per cent of them, mostly