An immunocytochemical study of lymphocyte and macrophage populations in the bone marrow of patients with non-Hodgkin's lymphoma.

Pairs of bone marrow trephine samples from 67 patients with known or suspected non-Hodgkin's lymphoma (NHL) were collected. One sample was processed for morphological examination, the other for frozen section immunohistology, using a panel of monoclonal antibodies (MAB) reacting with lymphocyte and macrophage determinants, detected by the immuno-alkaline-phosphatase (APAAP) method. Forty-one cases showed definite (36) or suspected (5) involvement of the marrow by NHL. Most were examples of lymphocytic or centroblastic/centrocytic NHL. The pattern of immunostaining confirmed the presence of NHL in these cases: the phenotype of the neoplastic cells was broadly consistent with nodal histology, where available. In ten cases, the marrow showed no evidence of involvement by NHL, and in 15, the eventual diagnosis was an abnormality of the myeloid series. These two groups of marrows not involved by NHL both showed a 'reactive' pattern of immunostaining, comprising polyclonal B-cells, T-helper and suppressor/cytotoxic cells and macrophages. We conclude that immunohistological examination of the bone marrow is useful in cases where the specimen shows morphological evidence of NHL, including those that are only 'suspect', but does not detect lymphoma where there is no morphological evidence of involvement.