RECONSTITUTION OF PERIPHERAL-BLOOD LYMPHOCYTE SUBSETS IN THE LONG-TERM DISEASE-FREE SURVIVORS OF PATIENTS WITH ACUTE MYELOBLASTIC-LEUKEMIA

The number of long-term survivors of patients with acute myeloblastic leukemia (AML) has increased as a result of the progress of chemothera py. We examined the recovery of peripheral blood lymphocytes (PBL) sub set after chemotherapy to clarify the reconstitution of the immune sys tem in AML, Thirty patients with AML in complete remission (CR) were e ntered into the study. There were 12 males and 18 females; one M0, six M1, 14 M2, three M3, two M4 and four M5 according to FAB classificati on, The age ranged from 21 to 78 years (median age, 46 years] and the duration of disease-free survival after completion of chemotherapy ran ged from 5 to 122 months (median, 35 months). The chemotherapy was per formed according to the protocol designed by the Japan Adult Leukemia Study Group (JALSG). PBL subsets were analyzed by flow cytometry with the use of monoclonal antibodies against CD2, CD3, CD4, CD5, CD8, CD16 , CD20, CD45RA, CD56, CD57 and HLB-DR. There was a significant positiv e relationship between the absolute number of CD4(+), CD45RA(+) CD4(+) cells and the duration of time post-therapy and a significant negativ e relationship between %CD5(+) B, CD56(+) cells and the duration of ti me post-therapy, The appearance of autoantibodies (rheumatoid factor a nd anti-DNA antibody) tended to increase after 2 years, however, there was no relationship between CD5(+) B cells and the frequency of rheum atoid factor. These findings demonstrate that patients in CR have a lo w number of CD4(+) and CD45RA(+) CD4(+) T cells at an early period aft er chemotherapy and that each subset recovered to a normal level in 2 years, %CD5(+) B and CD56(+) cells gradually decreased and returned to their normal level after 4 years, There were high numbers of DR+ T ce lls and NK cells for a long time, suggesting that activated T cells an d NK cells may play a role in the immune surveillance system after che motherapy.