Background. Immunophenotyping of malignant lymphomas becomes necessary for the correct classification, for the design of therapy and for prognosis projection (WHO). Although the spectrum of classic immunohistochemical (IHC) examinations in paraffin embedded or frozen sections has recently considerably extended, IHC should preferably be combined with flow cytometry. The main advantage of flow cytometry is a synchronous application of two or more antibodies marked with various fluorochromes in one sample. The method is limited by utilizing native material only. Methods and Results. The flow cytometry combinedwith histological and IHC investigations were used in diagnosis of primary non-Hodgkin’s lymphomas of B-cell origin (B-NHL) and for bone marrow staging or restaging. We studied 90 patients with confirmed or suspected B-NHL and we found a good correlation in 89 % of samples of primary lymphomas and in 85 % of bone marrow samples when IHC and flow cytometry results were compared. The overall efficacy of the flow cytometry determination in lymphoma infiltration of the samples was 89 %. Conclusions. Immunophenotyping utilizing flow cytometry contributes to diagnosis and classification of B-cell lymphomas in the significant proportion of investigated patients. In some cases it is even unnecessary to employ IHC examination of tissue sections. The method is especially suitable for determination of monoclonal populations of B-cells by detection of cell surface markers because it is more specific and sensitive than IHC. The immunophenotyping by flow cytometry as an auxiliary method and in correlation with morphological findings it can make the diagnosis of B-cell lymphomas faster and more specific.

        Key words: malignant lymphomas, monoclonality, lymph nodes, bone marrow, flow cytometry.