Lymphoid crisis with T-cell phenotypes in a patient with Philadelphia chromosome negative chronic myeloid leukaemia

Abstract

Summary A case of Philadelphia (Ph¹) chromosome negative chronic myeloid leukaemia (CML) developed lymphoid crisis. Immunological marker studies disclosed that the lymphoid cells were sheep erythrocyte‐rosetting^‐, Leu‐1⁺, Leu‐5⁺, OKT‐4⁺, OKT‐8⁺, common ALL antigen^‐, HLA‐DR^‐, cytoplasmic and surface immunoglobulin^‐, MAS 036C(antithymocyte)⁺ (after in vitro culture) and terminal deoxynucleotidyl transferase^‐, indicating T‐cell phenotypes, probably of common thymocytes. Cytochemical staining also demonstrated immature T‐cell characters: dot‐positivity for acid phosphatase and beta‐glucuronidase, and negative for acid alpha‐naphthyl acetate esterase. All bone marrow metaphases exhibited normal karyotypes. Our observation suggests that the neoplastic features of a common stem cell for myeloid and lymphoid cell lines are very similar in Ph¹ positive and negative CMLs, and that the stem cell can differentiate towards T‐lineage.