Histochemical demonstration of acid phosphatase activity in various blood cells.

Acid phosphatase activity of various blood cells were histochemically observed on peripheral blood and bone marrow smears using the azo dye method which had been reported in my previous paper, and following results were obtained. 1) In the neutrophilic granulocyte series, the largest acid phosphatase score was obtained in immature cells, which might include promyelocytes, myelocytes, and metamyelocytes. Mature neutrophils were stained moderately, and blast cells showed weak staining. 2) Eosinophils showed strong activity, and basophils seemed to have weak activity. 3) Monocytes disclosed strong activity, and lymphocytes slight activity. 4) Erythroblasts had slight activity, and it seemed that they lost gradually the enzyme activity with the advance of cell maturation. 5) In plasma cells, reticulum cells and megakaryocytes, strong activity of the enzyme was demonstrated. 6) Mast cells showed moderately strong activity on the bone marrow smears from a case of urticaria pigmentosa.