Philadelphia chromosome‐positive blastic leukaemia: ultrastructural and ultracytochemical evidence of basophil and mast cell differentiation

Abstract

Ultrastructural, ultracytochemical, immunologic and biochemical studies were performed on leukaemic cells from 41 patients with Philadelphia chromosome-positive blastic leukaemia; 28 patients were in blast transformation of chronic myelogenous leukaemia and 13 patients presented with 'acute' leukaemia. The patients were divided into two morphologic groups, lymphoid (16 cases) and myeloid (25 cases), on the basis of light microscopy and cytochemistry. All lymphoid cases studied for the presence of CALLA (10 patients) and TdT (11 patients) were positive. Two of 13 myeloid cases studied were TdT positive. The blasts from 10 of 16 lymphoid cases contained immature basophil/mast cell granules on ultrastructural examination. Peroxidase-positive 'lymphoid' blasts were noted in three of seven patients studied by ultracytochemical techniques. The reactivity was primarily confined to granular structures. Of the 25 cases in the myeloid group, blasts from 14 cases showed basophil/mast cell differentiation, nine cases showed neutrophil/monocyte features, and two cases were megakaryoblastic. Distinct patterns of ultrastructural peroxidase positivity were seen in the seven myeloid cases studied. In basophil/mast cell precursors the reactivity was primarily confined to granules; neutrophil precursors showed reactivity in the nuclear envelope, rough endoplasmic reticulum (RER), golgi and granules; in megakaryoblasts, only the nuclear envelope and RER were positive while the granules were consistently negative.

Peroxidase Activity in Mast Cell Granules in Urticaria pigmentosa

“…In human, in the case of myeloproliferative syndrome, intermediate cells between basophils and mast cells have been reported [3][4][5][6][7][8]. In some cases, the transitional cells exhibited peroxi dase activity in their cytoplasmic granules.…”

“…The most common clinical manifesta tion of UP is a generalized pigmented skin lesion consist ing of macules and papules distributed chiefly on the trunk and occasionally on the extremities and the head [2], The cause of UP is still unknown and the origin of mast cells in the lesion is obscure. Recently, in the cases of myelopro liferative syndrome, intermediate forms between baso phils and mast cells were reported and the presence of a common precursor cell for human mast cells and basophils has been suggested [3][4][5][6][7][8],…”

The role of the bone marrow in allergy and asthma

“…The immunophenotype of mast cells is distinct from that of basophils and eosinophils (43). Thus, the c-kit mediates only mast cell differentiation (31,32,43,44), with some exceptions of the hybrid basophil-mast cells in human bone marrow disorders (45)(46)(47)(48). The uniqueness of the mast cell lineage is underscored by recent experiments done in the W / W rat suggesting a biologic dissociation from the basophil lineage (49, 50).…”

Acute basophilic leukaemia and translocation t(X;6)(p11;q23)

“…Our cases illustrate the difficulty in identifying this group of acute leukaemias, reported by several authors (Wick et al, 1982;Parkin et al, 1982;Peterson et al, 1991;Dick, 1991). This difficulty is probably due to the rarity of basophilic maturation signs and also to the variation in percentages of basophilic infiltration.…”