Macrophage infiltration in non-Hodgkin's lymphomas: a quantitative in situ study

The frequency and distribution pattern of macrophages within 93 non-Hodgkin's lymphomas (NHL) were evaluated in situ by immunomorphometry using stereological methods. For the identification of macrophages (M phi), several antibodies (Mono 1, Mono 2, OKM 1) reactive with surface antigens on cells of the monocyte-macrophage series and cytochemical staining for acid phosphatase were applied. The average number of macrophages within lymph node tissue of NHL was 6,299 +/- 760 cells/microliter (similar to reactive lymphatic tissue: 6,559 +/- 1,027). The highest number of infiltrating macrophages was detected in immunoblastic NHL (17,306 +/- 2,773), differing significantly from other histological subtypes and reactive lymphatic tissue (p less than 0.005). The possible impact of tumor-infiltrating macrophages on lymphoma cell proliferation and differentiation is discussed.