Contribution of flow cytometric immunophenotyping and bone marrow trephine biopsy in the detection of lymphoid bone marrow infiltration in non-Hodgkin's lymphomas

The bone marrow (BM) is a frequent site of involvement in non-Hodgkin's lymphomas (NHL) and evidence of an infiltrated BM may implicate different therapeutical regimens. Flow cytometric immunophenotyping of bone marrow aspirates now is included in the assessment of patients with NHL and used as an adjunct to morphologic evaluation in the staging of lymphoma. The aim of the study was to compare flow cytometric immunophenotyping of BM and paraffin section staining of BM biopsies in the marrow involvement of NHL. Cytometric immunophenotyping of bone marrow and immunohistochemical paraffin section staining of bone marrow biopsies in 53 B- and T-cell lymphoma patients were performed. We used the following fluorochrom conjugated monoclonal antibodies specific for: CD3, CD4, CD5, CD7, CD8, CD10, CD19, CD20, CD22, CD23, CD79B, FMC7 and Ig kappalambda light chain. Unilateral BM trephine biopsies were obtained in all cases, fixed, decalcified and paraffin-embedded. Morphologic marrow involvement by lymphoma was found in 24 cases; flow immunophenotyping identified 26 cases with NHL: morphology-positive/flow-positive (n=21), morphology positive/flow-negative (n=3), morphology-negative/flow-positive (n=4), and morphology-negative/flow-negative (n=23). The concurrence rate of BM trephine biopsy and flow cytometric immunophenotyping in evaluation of NHL bone marrow infiltration was 88.7%. Immunophenotyping of the bone marrow of NHL patients by flow cytometry is helpful for assessment of bone marrow infiltration, especially in B-cell disorders. Both trephine biopsies and flow cytometry are better than single investigation for detection of infiltration in NHL.