IMMEDIATE BROMODEOXYURIDINE LABELING OF UNSEPARATED HUMAN BONE-MARROWCELLS EX-VIVO IS SUPERIOR TO LABELING AFTER ROUTINE LABORATORY PROCESSING

It is important to evaluate the proliferation of bone marrow cells in several disease conditions and during treatment of patients with for e xample cytokines. Labelling with bromodeoxyuridine (BrdUrd), immunocyt ochemical staining with anti-BrdUrd antibody and analysis by flow cyto metry provides a reliable and reproducible technique for estimation of the fraction of cells that incorporated BrdUrd into DNA during S-phas e. We have compared immediate BrdUrd labelling of unseparated bone mar row cells with the previously used labelling in the laboratory after r outine separation of the mononuclear cells. Bone marrow aspirates from seven lymphoma patients without bone marrow involvement were studied with these two methods. We found higher BrdUrd labelling indices (LI) in the mononuclear cells, when cells were labelled immediately. A larg e variation in LI was found between patients. Our results suggest that ex vivo BrdUrd labelling of bone marrow cells should be performed imm ediately after aspiration and before separation, because these data ar e closer to values reported from in vivo labelling with BrdUrd.