Immunophenotyping of T-lymphoblastic lymphoma/leukemia: correlation with normal T-cell maturation.

Twenty-nine cases of T-lymphoblastic lymphoma/leukemia were classified with conventional morphologic methods and the aid of monoclonal antibodies. All cases were investigated with a sensitive immunohistochemical method, using a panel of 22 monoclonal antibodies. In addition, normal thymus glands in the 22nd and 36th weeks of gestation were studied. Eight different groups of T-lymphoblastic lymphomas/leukemias could be distinguished, each of which showed a characteristic marker constellation. The results indicate that a complete detection of all thymic and prethymic lymphomas and leukemias is possible. By comparison with the phenotypic pattern of normal peripheral T-lymphocytes and their thymic precursors, the groups could be arranged in a sequence that resembles normal T-cell maturation, monoclonal antibodies.