[The problems of immunological diagnosis of childhood acute leukemia and non-Hodgkin's lymphoma].

The immunophenotyping of leukaemia and non-Hodgkin's lymphoma cells is based on staining the cells with monoclonal antibodies against surface and cytoplasmic determinants followed with flow cytometry analysis. The problems of immuno-phenotyping are associated with technical difficulties, changes in expression of determinants and the rare types of leukaemia and haematological disorders typical for newborns and infants. The lack of blast cells within cell suspension obtained for test may be the result of bone marrow disorder (aplastic anaemia, preleukaemic cytopenia) or technical pitfall. The changed expression of determinants on blastic cells observed as weak expression or overexpression or atypical combination of determinants requires a careful interpretation. In the diagnosis of rare types of acute leukaemia (e.g. erythroleukaemia, megakaryoblastic leukaemia, mixed lineage or undifferentiated leukaemia) the additional monoclonal antibodies beyond routine set are needed. A special concern is necessary in diagnosis of newborns and infants leukaemia or bone marrow disorders like myelodisplastic syndrome particularly in children with other systemic diseases e.g. congenital immunological deficiencies, Down's syndrome. The problems of immunophenotyping in non-Hodgkin's lymphoma are frequently associated with obtaining a representative material e.g. surgical tumour biopsy, lymph node. In some case the differential diagnosis including small round cell tumours and anaplastic type of lymphoma is necessary what requires an additional set of monoclonal antibodies. Despite of modern technology, morphology, immunophenotyping and histopathology remain the standard of complex diagnosis of lymphoproliferative diseases and haematopoietic disorders in children.