http://repub.eur.nl/res/aut/4437/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/21461/ 2010-01-01T00:00:00Z Chemotherapy for childhood acute lymphoblastic leukemia may cause severe immune damage. The lymphocyte compartment of 140 patients during and after a new strongly reduced (standard risk (SR), n = 43) and intensive chemotherapy regimen (medium risk (MR), n = 97) was studied between 2006 and 2009. Transitional and naive B cells and IgG+/A+, IgM+ and IgM only memory B cells were significantly reduced during chemotherapy; significantly more in MR group. One year after treatment CD27+IgG+/A+, IgM+ and IgM only memory B cells had still not fully recovered, but this was not confined to the MR group. The T cell compartment was less but also significantly affected during chemotherapy and recovered to normal levels. In the MR group, NK cells had not fully recovered to normal levels 1 year after treatment. Thus, intensive chemotherapy regimens cause severe, mainly B cell memory damage that persists even 1 year after treatment. http://repub.eur.nl/res/pub/9419/ 2000-01-01T00:00:00Z Recently the Belgium-Dutch Hematology-Oncology group initiated a multicenter study to evaluate whether myeloma patients treated with intensive chemotherapy benefit from additional peripheral stem cell transplantation. To determine treatment response accurately, we decided to quantitate malignant cells. To test a consensus quantitation strategy, 5 centers independently determined the immunoglobulin heavy chain sequences of patient tumor cells and developed allele-specific oligonucleotides (ASO) and ASO-polymerase chain reaction (PCR). We compared the reproducibility of real-time quantitation with quantitation using limiting dilutions. We distributed DNA samples with a 4-log range of tumor cell concentrations and found average quantitation values deviating 74% and 42% from the input values with real-time PCR (1 center) and limiting dilutions (4 centers), respectively. Within single centers we found an average variation coefficient of 0.74, with limiting dilutions not significantly different from the average 0.82 center-to-center variation coefficient. Within a single center, real-time quantitation proved more reproducible (average variation coefficient, 0.36). Quantification was confirmed in 3 patients during treatment in the protocol. This report shows that real-time PCR or limiting dilution assays can be used for quantitation in a single multicenter trial. We present a consensus strategy that allows an accurate comparison of quantitation data generated in independent centers.