[Diagnostic value of immunological lymphocyte differentiation].

The morphologically homogenous population of circulating lymphocytes can be further differentiated by immunological methods. A proportion of the cells bear immunoglobulins on their surface, as evidenced by immunofluorescence; these are either cells of the B-lymphocyte line at a stage of producing surface immunoglobulins (antigen receptors) or lymphocytes which acquire immunoglobulins from outside by various mechanisms. Other circulating lymphocytes, attributed at least partly to T-cells, form rosettes with desensitised sheep erythrocytes. Determination of the percentage of surface immunoglobulin positive lymphocytes or rosette forming cells has been used by many investigators to further characterize (subdivide) various diseases. Conflicting results were obtained, mainly due to wide variations in the technique used. Most patients with chronic lymphatic leukemia show a strongly elevated proportion of surface immunoglobulin cells. Also, in non-Hodgkin lymphomas the percentage of such cells is elevated even the absolute number of peripheral lymphocytes and their morphology is normal. Patients with Waldenström's disease often displays an elevated proportion of IgM carrying cells. Many other diseases are associated with unbalanced ratios between immunoglobulin positive and rosette forming lymphocytes. Some of the relevant results of the literature are discussed with reference to their diagnostic value.