Minimal residual disease (MRD) monitoring using rearrangement of T‐cell receptor and immunoglobulin H gene in the treatment of adult acute lymphoblastic leukemia patients

We evaluate whether molecular monitoring of minimal residual disease (MRD) using TCR δ (TCRD), TCR γ (TCRG), and immunoglobulin H (IgH) gene rearrangements in the bone marrow (BM) is correlated with clinical events in ALL patients. The 14 patients enrolled in this study included 6 males and 8 females with a median age of 53 years (range, 25–79 years), and the median duration of follow‐up was 417 days (range, 57–617 days). The median WBC count was 11.3 × 10 9 /L at diagnosis. All patients had L2 type ALL. Eleven patients had a monoclonal pattern of IgH (7), TCRD (3) and TCRG (1), and 3 patients had two clonal patterns. Eleven of the 14 patients achieved the first complete remission (CR) after the first induction chemotherapy. We analyzed 9 of 11 CR patients who could be examined immediately after induction chemotherapy (including re‐induction therapy). Event‐free survival (EFS, 0%) and disease‐free survival (DFS, 0%) at 1 year in CR patients with MRD level ≥10 −3 ( n = 3) were significantly lower than those in CR patients with MRD level <10 −3 ( n = 6) (log‐rank test, P = 0.013, 0.013). A lower MRD in BM value after induction chemotherapy was associated significantly with longer survival in the log‐rank test. Our data provide evidence that molecular MRD status of BM is a strong predictor of outcome in adult ALL. Am. J. Hematol. 80:181–187, 2005. © 2005 Wiley‐Liss, Inc.