An immunohistochemical study of non-Hodgkin's lymphomas: correlation of morphological appearances and immunophenotype in 148 cases.

An unselected series of 148 cases of non-Hodgkin's lymphoma has been studied by immunohistological methods. In each case, the morphological features displayed in paraffin sections were correlated with the immunophenotype, determined using a panel of monoclonal antibodies. Of the lymphomas 82% were B-cell type, 28% of follicle centre cell origin, 17% lymphocytic or immunocytic and 30% of large cell type. All the B-cell tumours expressed pan-B antigen, and nearly all HLA-DR. In most, light chain monoclonality was demonstrable. Nearly all had moderate to large numbers of T-cells of both subtypes interspersed amongst the B-lymphocytes. Follicle centre cell tumours expressed surface IgM and IgD and had numerous dendritic reticulum cells. Lymphocytic and immunocytic lymphoma expressed IgM but less IgD, and had fewer or no dendritic reticulum cells. Large cell lymphoma expressed either no immunoglobulin or only IgM, and contained ragged dendritic reticulum cells, giving the appearance of 'burnt-out' follicles. T-cell lymphomas usually showed a clear preponderance of either helper or suppressor subtype. Additionally, they contained residual B-cells and sometimes germinal centres. Only 3% of this series were 'non-B, non-T', and only one case HLA-DR negative, so the 'null' or 'unclassifiable' group is very small when information from antibody markers is available.