Cell replication in an immunologically(?) Stimulated cell population in human bone marrow.

In AIDS, although there is a lack of humoral responsiveness in vitro and in vivo, many patients persistently have an increased number of B cells which continue to produce increased amounts of immunoglobulin. An objective, reproducible morphologic classification scheme for B cells was devised. Comparison of cell kinetic parameters in various disease states will require such a classification. Although not immunologically responsive to new stimuli, the marrow B cells in the AIDS patients were shown to be replicating and turning over. The latter may be due to either death in situ or to migration. Plasmacytic lymphocytes and lymphocytic plasma cells, morphologic transitions between lymphocytes and mature plasma cells, had the largest fractions in DNA synthesis. Because of their relative cell numbers, the lymphocytic plasma cells contained most of the cells in DNA synthesis. The position of plasmablasts in the sequential compartments is unclear. Only small numbers are dividing. Within a given morphologic category, large cells were more likely to be in DNA synthesis than smaller cells. These studies can serve as a basis for comparison with marrow B-cell proliferation in other disease states.