Alexander Gaiger

Early detection of relapse after bone marrow transplantation in patients with chronic myelogenous leukaemia

In patients with chronic myelogenous leukaemia (CML) treated by allogeneic bone marrow transplantation (BMT), detection of residual leukaemic cells carrying the characteristic bcr/abl rearrangement by highly sensitive techniques, such as qualitative polymerase chain reaction (PCR), is of limited value in predicting disease progression. We have therefore adapted the PCR for quantitative assessment of bcr/abl rearranged cells and applied this technique to the monitoring of residual disease in 28 CML patients during up to 106 months of follow-up after BMT. In 5 patients, quantitative PCR revealed increasing amounts of the pathological bcr/abl message, indicating the presence of a proliferating neoplastic clone, and all 5 had a subsequent relapse of disease. By contrast, the remaining 23 patients have been in maintenance-free complete remission for up to 106 months post-BMT. The monitoring by quantitative PCR of residual leukaemic cells during the post-transplant course of CML patients may allow early detection of relapse and provide a rationale for the timely initiation of treatment.

Prognostic significance of WT1 gene expression at diagnosis in adult de novo acute myeloid leukemia

We examined the presence of WT1-specific mRNA in bone marrow samples of 125 patients with de novo acute myeloid leukemia at diagnosis by two-step RT-PCR. The sensitivity of the assay was 1:100 (first step) and 1:10 000 (second step), respectively. WT1-specific mRNA was detected in 73% of patients. No correlation was found between WT1 gene expression and age, FAB type, LDH and karyotype at diagnosis. All patients were treated with standard induction chemotherapy. There was no difference in the CR rate between WT1-positive and -negative patients. Using Kaplan and Meier plot analysis we found no difference in disease-free survival (DFS) and overall survival (OS) between patients displaying the WT1 transcript and WT1-negative patients. Furthermore, no significant interactions between WT1 PCR results and age, FAB type, LDH and karyotype on DFS and OS were demonstrable using Cox regression analysis. Eight patients who were WT1 PCR positive at diagnosis and achieved complete hematological remission following chemotherapy were monitored during the course of the disease. Based on our limited data demonstrating a heterogenity of WT1 PCR results in CR we cannot draw any conclusions regarding the usefulness of WT1 PCR analysis for the early detection of relapse. We conclude that WT1 gene expression at diagnosis is not associated with specific characteristics of AML blast cells and is not a prognostic factor for CR, remission duration and overall survival in acute myeloid leukemia.

Detection of the WT1 transcript by RT-PCR in complete remission has no prognostic relevance in de novo acute myeloid leukemia

The WT1 gene is expressed in 73–100% of patients with acute myelogenous leukemia (AML) and is thought to play a role in maintaining the viability of leukemic cells. WT1 has been proposed as a marker for minimal residual disease in leukemia. We obtained serial blood or bone marrow samples from patients with de novo AML at diagnosis, during therapy, and up to 95 months after diagnosis and analyzed for WT1 gene expression by RT-PCR to determine whether gene expression was predictive of relapse. Forty-four patients had WT1-positive AML and achieved a complete remission (CR) following chemotherapy and 24 patients underwent unrelated donor (n = 4), sibling donor (n = 13) or autologous (n = 7) marrow transplantation. After achieving CR 62% of the patients became WT1-negative, while 38% remained WT1-positive. There was no difference in the disease-free survival (DFS) and survival from remission between WT1-positive and -negative patients (P > 0.1). Following BMT, 32% of the patients analyzed in CR within the first 100 days after transplantation were WT1 PCR positive. Detection of WT1 transcripts within 100 days following BMT did not affect DFS and overall survival (OS) after transplantation (P > 0.1). Ten of 11 patients who are in continuous CR following chemotherapy or BMT for more than 3 years were transiently WT1-positive during the observation period. Four of these patients displayed the WT1 transcript at the last examination. Thirteen of 39 patients were WT1 PCR negative within 4 months before clinical onset of relapse and eight patients were WT1 PCR negative at time of relapse. These data indicate that: (1) achievement of WT1 negativity is not associated with longer DFS, survival from remission, or OS after transplantation; (2) not all patients who relapse become WT1 positive again; (3) long-term remitters frequently display the WT1 transcript. Thus, we conclude that the monitoring of WT1 gene expression by qualitative RT-PCR during treatment and CR is of very limited value.

Pure red cell aplasia in a case of Ph negative BCR/ABL rearranged CML with t(12;14)(q23;p11)☆

A patient with chronic myelogenous leukemia (CML) associated with pure red cell aplasia (PRCA) is reported. The occurrence of PRCA has been described previously in sporadic cases of Philadelphia chromosome (Ph) positive CML. In this patient, however, the Ph-chromosome was not detected; cytogenetic analysis revealed a t(12;14)(q23;p11) as the sole abnormality. Molecular studies by Southern and PCR analyses showed the rearrangement of the BCR and ABL sequences and expression of the chimeric bcr/abl mRNA, thus confirming the diagnosis of CML. To our knowledge, this is the first report on a case of PRCA associated with Ph negative CML at diagnosis. The possible connection between CML and PRCA is discussed.

Simultaneous Occurrence of t(8;21) and del(5q) in Myeloid Neoplasms

The translocation t(8;21)(q22;q22) and the deletion of the long arm of chromosome 5, del(5q), are two acquired chromosome abnormalities which characterize distinct biological entities of hematologic neoplasms. We have observed two patients, a 9 year old girl with refractory anemia with excess of blasts in transformation (RAEB-T) overting to M2-AML and a 50 year old woman with refractory anemia with excess of blasts (RAEB) in whom both abnormalities concurred in the same cell clone. After chemotherapy the girl underwent a successful allogeneic bone marrow transplantation (BMT) from her sister and has remained in complete remission two years after diagnosis. The other patient received only erythrocyte transfusions and has been in stable condition for three years. In addition, a 33 year old man with a complex translocation t(5;8;21)(q13;q13;q11) is presented for comparison. His hematologic findings and clinical course was similar to that of other patients with a t(8;21). We conclude that in cases with two specific karyotype changes the biological features typically associated with one or the other chromosome abnormality may dominate the phenotype. It remains unclear whether the clinical and hematological appearance of the disease is determined by the abnormality which occurs first or by the one which predominates.