[Host reaction in non-Hodgkin's lymphomas: tumor infiltration with monocytes/macrophages]

The number and distribution of macrophages in deep frozen sections of various non-Hodgkin lymphomas (NHL) were evaluated in situ by immunomorphometry using stereological methods. The density of infiltration was correlated with clinical parameters. Several monoclonal antibodies reactive with antigens present on cells of the monocyte-macrophage series were tested in parallel. The density of macrophages within NHL of high malignancy with 11.3 X 10(3) +/- 1739 positive cells/microliter tumour tissue was higher than in those of low malignancy (4.7 X 10(3) +/- 628). The highest value of positive cells was found in immunoblastic lymphoma (17.3 X 10(3) +/- 2773), differing significantly from other histological subtypes of NHL and normal tissue (normal tissue: 6.5 X 10(3) +/- 1027, p less than 0.005). With regard to clinical parameters, localized NHL displayed lower infiltration numbers than generalized NHL. Possible mechanisms of influencing tumour growth are discussed in view of the large infiltration density of the monocyte macrophage series in NHL of unfavourable histology and advanced clinical stage.