The value of immunophenotyping cryopreserved bone marrow trephine biopsies in lymphoma and leukaemia

In this study of 163 cryopreserved bone marrow (BM) trephine biopsies, immunophenotypes of BM infiltrates have been characterised in detail (103 in B non-Hodgkin's lymphoma [NHL], 22 in T-NHL and 38 in acute leukaemia).In B-NHL, 57 marrows were infiltrated on conventional trephine analysis, 41 on immunohistological analysis of cryosections and 38 on immunophenotypic analysis of BM aspirates (one out of 38 lacked infiltration on conventional analysis). Combining results of cryosection and aspirate analysis allowed 83% of infiltrates to be immunophenotyped.The T-NHL cases included 18 peripheral T cell lymphomas (PTCL). 13/18 cases had BM infiltration (seen on both conventional and cryosection analysis). Of these 13 cases only 2 showed infiltration on BM aspirate immunophenotyping. PTCL cases with BM infiltration frequently presented with profound peripheral blood cytopenia and had median survival of only 6 months. 12/13 cases were CD3 positive in BM infiltrates, 5/10 CD4 positive, 1/13 CD8 positive and 9/12 HLA-DR positive. Shortest survivals were seen in 4 cases with selective CD7 negativity in the presence of other pan T cell markers.Proliferative activity was assessed in infiltrated BM cryosections using the monoclonal antibody Ki-67. In pretreatment cases mean Ki-67 positivity in infiltrates was 0.3% in low grade B-NHL, 20% in high grade B-NHL and 16% in PTCL. In common acute lymphoblastic leukaemia mean Ki-67 positivity was 25% which was significantly higher than the 2.5% positivity seen in acute myeloid leukaemia. BM cryosection analysis facilitated diagnosis in acute leukaemia in a small number of cases where aspirate volumes were inadequate.