Detection of minimal residual disease (MRD) in acute lymphoblastic leukemia with flow cytometry is based on precise description of leukemia cell at diagnosis including aberrant expression of determinants. The important clinical significance of MRD is in time of obtaining the first remission of acute leukemia. The problems with MRD assay and interpretation of results in acute lymphoblastic B and T leukemia are discussed.

The basic indications for immunophenotype assay in diagnosis of non-Hodgkin's lymphoma (NHL) in children including monoclonal antibodies sets are shown. Classification and description of given types of NHL in children and clinical significant of determinants expression are discussed.

Immunophenotyping is a significant method for hematooncology diseases diagnosis and treat- ment. The knowledge about normal hematopoiesis enables the estimation of aberrant antigens patterns in pathological specimen. In this paper the authors are presenting immunophenotypic differentiation pat- terns in normal hematopoiesis. A three-, four-, and six color flow cytometry analysis scheme of antigens expression have also been proposed.

Antibodies are protein particles capable of specific antigen binding. Policlonal antibodies comprise of a group of antibodies that recognize different epitopes of the same antigen. Monoclonal antibodies recognize and bind to only one specific epitope. Both types of antibodies have their applica- tions in diagnostic techniques, however only monoclonal antibodies are used in flow cytometry. Conjuga- tion of monoclonal antibodies with fluorescent dyes enables the detection of antigens of different cell types.