This study was undertaken to find out some clue to detect early relapse of adult acute leukemia which had been in remission. Laboratory data such as LDH, erythrocyte sedimentation, or immunoglobulin level did not show any difference at the time of relapse from the remission period. Complete blood count with reticulocyte count was evaluated every two weeks retrospectively for 12 weeks before relapse. No significant change was observed at the time of relapse. However, both the percentage and absolute number of peripheral lymphocytes significantly increased, whereas percentages of both T and B cells markedly decreased at the time of relapse, suggesting some derangement of lymphocyte function. Results in bone marrow culture did not yield any remarkable difference. It was suggested from this study that it is the time of prerelapse of adult acute leukemia when lymphocytes show an increase in either percentage or absolute number in the patients who are followed under their maintenance therapy schedule. clinical sign; early relapse; adult acute leukemia; percentage of lymphocyte; T lymphocyte Nationwide studies on the remission induction therapy of adult acute leukemia have been performed, but the mechanism of relapse in acute leukemia remains to be elucidated. In our previous reports, we examined the factors of hosts, types and nature of leukemia, and the methods of therapy to discover the most influential factor for long survival of adult patients with acute leukemia. It was concluded that maintenance therapy in remission was the most important factor (Kawamura et al. 1977). This implies that elongation of remission is the most important for longer survival. Therefore, it is of clinical importance to predict the relapse and to resume the treatment as early as possible.In order to detect early signs of relapse in adult leukemia without frequent bone marrow punctures, hematological and immunological examinations and tissue culture studies of bone marrow cells were undertaken in the present study.It was found that the relapse of adult acute leukemia was indicated when lymphocyte counts exceeded 40 to 50% or T and B cells decreased significantly in the patients on maintenance therapy.

A criterion was established in a previous study to detect the relapse of adult acute leukemia in its early stage, i.e., when lymphocytes in peripheral blood increased over 45% of the leukocytes during the maintenance therapy, bone marrow puncture was immediately performed to examine the leukemic cells. By this criterion the relapse was detected earlier than by other criteria. To study the effect of early detection of the relapse in adult acute leukemia on the results, the second remission rate and the survival time were compared between the following groups. Group I consisted of 11 patients, whose relapse was determined by our criterion. Group II consisted of 8 patients whose relapse was determined by the appearance of leukemic cells in peripheral blood. The second remission was accomplished in 7 of 11 patients in Group 1(64%) and in 1 of 8 in Group 11 (13%) (p <0.05). The mean (+s.D.) duration of complete remission in Group I was 9.7+ 7.8 months and not significantly longer than the value in Group 11(5.3 +3.9 months). The interval from relapse to death was 10.3±5.9 and 6.1±3.8 months in Groups I and II, respectively. The interval from relapse to death of 7 patients who accomplished the second remission in Group I was 12.5+5.5 months. This interval was significantly longer than in Group II (p <0.02). The mean survival time was 22.2± 9.6 months in Group I and 13+ 2.5 months in Group II. The mean survival time of 7 patients accomplished the second remission in Group I was 26. 7±9.4 months which was significantly longer than in Group II (p <0.01). The results showed that our criterion to detect relapse in the early stage was effective for prolongation of the survival time in adult acute leukemia. early detection of relapse ; adult acute leukemia ; percentage of lymphocyte ; survival time ; second remission rateThe complete remission rate in adult acute leukemia in Japan has recently been over 80% owing to the development of antileukemic agents and improved combination chemotherapy. Next important problems in control of acute leukemia in adults would be the duration of maintenance therapy, the time of second

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