Clinical significance of plasmacytosis in the day+14 bone marrow of patients with acute myeloid leukaemia undergoing induction chemotherapy.

BACKGROUND

The design of chemotherapy-induction regimens for acute myeloid leukaemia (AML) is directed towards the early elimination of bone marrow (BM) leukaemic blast cells (LBCs). Patients with AML after induction show LBC reduction in a hypoplastic BM and also demonstrate a varying number of residual BM plasma cells (PCs).

AIM

To relate PC number to several blood and BM parameters as well as clinical features such as infection and survival.

METHODS

On the 14th day after the start of chemotherapy (D+14) BM samples were examined for residual PCs in 60 adult (>or=15 years) patients undergoing AML-induction chemotherapy, and the proportion of PCs was related to blood and BM parameters including French-American-British (FAB) subtype, other inflammatory cells, antecedent infection, attainment of complete remission and 36-month survival.

RESULTS

Median PC proportion of 11.3% (range 0.1-48.7%) in D+14 BM aspirates and 10.7% (0.6-41%) in trephine biopsies was observed. Their number showed a direct relationship with residual BM lymphocytes (r=0.368; p=0.025). Higher numbers of residual PCs also reflected the presence of infection before diagnosis and coincident with treatment (p=0.039). Although we could not demonstrate an association between PC numbers and 36-month survival, PC numbers were significantly higher in patients with residual leukaemia at D>14 (p=0.007).

CONCLUSION

D+14 BM PC number reflects the effectiveness of induction chemotherapy and the presence of antecedent inflammation or infection.