Immunological typing of blast cells. Cases with pre-B cell characteristics.

Leukemic cells from 32 patients were examined by using conventional immunological markers (E and EAC rosettes, surface immunoglobulins). Additionally, the test for intracytoplasmic IgM, Fc IgG receptor and the presence of light chains were performed. Leukemic blasts of all patients were investigated according to morphological and cytochemical criteria. Lymphoblasts from 3 patients had pre-B cell phenotype: cIgM +, sIg-. Each of 3 patients with pre-B cell characteristics had different diagnosis and different morphological and cytochemical features of the leukemic cells (ALL, NHL and CML). In 24 ALL cases the diagnosis of non-T, non-B ALL, in 4 cases T-ALL and in one B-ALL was established. The correlation of cytochemical results with special reference to acid phosphatase and immunological subclasses of ALL was also analyzed. An important question is raised with regard to diagnostic classification and treatment by finding ALL phenotypes in lymphoproliferative disorders that are not diagnosed as ALL.