Early plasma cell recruitment in multiple myeloma following chemotherapy

Therapy-induced modifications of bone marrow plasma cell kinetics were studied in three patients with myelomatosis. The investigation was performed prior to and 15 d after termination of a course of aggressive chemotherapy. An increase in the labelling index (40-212% of pretreatment values) with a corresponding reduction of Ts (5-34%) was observed in all cases. As a consequence of this combined variation, the fractional turnover rate (which represents the percentage of cells produced per unit time) was the parameter with the highest increment (54-276%). These results indicate that plasma cell recruitment occurs soon after chemotherapy and is characterized by a shorter S phase and a higher number of DNA-synthesizing cells.