Klin Padiatr 2004; 216 - 25
DOI: 10.1055/s-2004-828570

Minimal residual disease in the bone marrrow of children with isolated extramedullary relapse of ALL

N Hanzsch 1, C Eckert 1, K Seeger 1, U zur Stadt 2, A Schrauder 3, G Henze 1, A von Stackelberg 1
  • 1University Charité, Berlin, Germany
  • 2University of Hamburg, Germany
  • 3Medical School Hannover, Germany

The extent of bone marrow (BM) involvement at diagnosis of childhood isolated extramedullary relapse (IEMR) of acute lymphoblastic leukemia (ALL) and its reduction during induction therapy at minimal residual disease (MRD) level has never been systematically analysed and related to prognosis. We have quantified the extent of sub-cytological BM involvement at relapse diagnosis in 22 patients with first relapse in the central-nervous-system or in the testis treated according to the ALL-REZ BFM protocols (90/96/02). MRD has been sensitively assessed by real-time-quantitative PCR using T-cell-receptor and Immunoglobulin generearrangements. A MRD-level <10-4 was measured in 5 patients. Seventeen patients showed a positive MRD-status: five <10-3 –=/>10-4, five <10-2 –=/>10-3 and seven >10-3. MRD-status was not significantly associated with relevant prognostic parameters. Our study reveals a large heterogeneity in patients with IEMRs with highly varying MRD-levels in different clinically defined groups. Now, we have a reliable tool to monitor sub-cytological response to treatment in patients with IEMR.

This work was kindly supported by the Deutsche Leukämie Forschungshilfe, Germany and by the Kompetenznetz der Pädiatrischen Onkologie, BMBF.