Immunofluorescence studies on immunoglobulins in the lymphoid cells of human peripheral blood.

Immunofluorescence was applied for the detection of intracellular immunoglobulins in human peripheral blood cells. The technique permitted the screening of large numbers of cells and the discrimination of two fluorochromes within each cell. In this way distribution patterns were obtained for the major immunoglobulin classes and for both light chain types. In contrast to the analogous bone marrow patterns there was no correlation with the distribution pattern of the immunoglobulins in the serum in the samples without paraproteinaemia. These results are compatible with the view that the bone marrow—but not the blood—is to be considered as a major source of the immunoglobulins in the serum. This hypothesis also implies that the initial phase of antibody production takes place in the peripheral lymphoid organs with a homing tendency of the immunoglobulin-producing cells in the bone marrow. The findings in paraproteinaemia support this view. Information about the quantitative contribution of the peripheral lymphoid organs is insufficient to draw definite conclusions. It became furthermore apparent that there can exist an intracellular imbalance with regard to the heavy versus the light chain components of the immunoglobulin molecules. The result often is an H/L ratio in excess of unity.