Surface immunoglobulin in immunoproliferative diseases.

Malignant B cells may originate from any of the stages of differentiation of B cells, primarily from IgM bearing B cells. The malignant B cells maintain a limited potential for differentiation. In addition to surface immunoglobulins, various markers may be present on the B cell surface; when surface Ig cannot be identified, these markers are used to identify B cells. However, for practical purposes, the detection of surface Ig is most important in the identification of B cells in immunoproliferative diseases, particularly when the malignant cell population displays only one immunoglobulin light chain. The procedures used so far to detect surface Ig have several drawbacks regarding their sensitivity or their specificity. The advantages of new procedures which involve the identification of B cells by their natural binding of B. melitensis or the detection of surface Ig by antibody-coated E. coli are presented. Detection of changes in the percentage of B lymphocytes and in the ratio of kappa- to gamma-bearing B cells in blood smears or in lymphocyte suspensions may be helpful in the early diagnosis of immunoproliferative diseases.