Ryoichi Inoue

B Cell Lymphoma Showing Clinicopathological Features of Malignant Histiocytosis

This report describes a case of B cell lymphoma, the clinicopathological features of which are quite similar to those of malignant histiocytosis. The clinical features included fever, anemia, and marked hepatosplenomegaly without lymphadenopathy. Histological findings revealed diffuse and noncohesive proliferation of cytologically atypical cells and benign-appearing histiocytes in the splenic red pulp, where the erythrophagocytosis was frequently found. Immunological studies, however, revealed a B cell nature of proliferating atypical cells. Accordingly, the histology of this patient was interpreted as a neoplastic proliferation of B cells accompanied by marked proliferation and activation of the histiocytes.

A case of T‐cell chronic lymphocytic leukemia (T‐CLL) expressing a peculiar phenotype (E+, OKM1+, leu 1+, OKT3− and IgG EA−)

A case of chronic leukemia is reported. Malignant cells had the morphology of lymphocytes and an affinity for skin. Cytochemically, they were peroxidase negative, and NaF‐resistant α‐naphthyl esterase positive. The peripheral mononuclear cells formed E‐rosettes and reacted with Leu 1 and OKM1. They were unreactive with OKT3, OKT4, OKT6, OKT8, and OKIa1. The cells did not possess surface IG, C3b receptors, or IgG Fc receptors (EAIgG). They responded weakly to phytohemagglutinin, and did not respond to concanavalin A. The cells did not adhere to Petri dishes or phagocytose latex beads. It is concluded that it was a case of OKT3−, OKM1+, EAIgG− T‐cell chronic lymphocytic leukemia. This suggests that OKT3 does not recognize all peripheral T‐cells, and that OKM1 is not specific for the monocyte—myeloid lineage. These cells may be useful in the characterization of E+, OKM1+ subset of peripheral mononuclear cells.

OKM1-positive T-cell leukemias. Relationships among morphologic features, phenotype, and functional activities

The morphologic features, phenotype, and functions of OKM1+ leukemic T‐cells were studied. The leukemic T‐cells in two patients with chronic lymphocytic leukemia (CLL) had specific features of large granular lymphocytes (LGL), and those in two patients with acute lymphocytic leukemia (ALL) had L2 morphologic characteristics. The phenotype of the leukemic cells from one patient with CLL was OKM1+, ER+, OKT3+, OKT4+, OKT8−, OKIa1−, IgGFc receptor (EAγ)+, Leu‐7+, Leu‐11b+, and anti‐Tac−. The cells had antibody‐dependent cell‐mediated cytotoxicity (ADCC), but no natural killer (NK) activity. They had a definitive helper effect on pokeweed mitogen‐induced normal B‐cell differentiation. The leukemic cells from the other patient with CLL were Leu‐7−, and Leu‐11b−, and lacked both ADCC and NK activity. The leukemic cells in the two patients with ALL were ER+, OKM1+, Leu‐7−, and Leu‐11−, and did not have any cytotoxicity. One was EAγ+, and the other was EAγ−. These findings suggest that OKM1+ leukemic T‐cells consist of at least two subgroups: (1) T‐cells with the morphologic features of LGL; and (2) those with a lymphoblastic morphologic type. In either case, the phenotype is novel and suggests the emergence of a small, distinct lymphocyte subset.