Detection of Minimal Residual Disease (MRD) in B Lymphoblastic Leukemia/Lymphomia (B-ALL) Using a 9 Parameter Kaluza Radar Plot
Joanne M Luider, Karan Paisooksantivatana, Adnan Mansoor, Iwona A Auer-Grzesiak. University of Calgary, Calgary, AB, Canada
Background: Identification of MRD in paediatric B-ALL to a sensitivity level of 0.01% is now routinely required for risk-stratified treatment protocols /clinical trials and is increasing in importance in adult patients (pts). In addition to all technical issues, data analysis is the most crucial step for identification and accurate quantification of MRD. For this purpose, sophisticated and extensive sequential gating strategies are generally utilized in many laboratories using different analysis software.
Design: Fifty bone marrow (BM) samples (adult =27; pediatric=23) B-ALL pts were analyzed utilizing a single 10-colour tube (CD58-FITC, CD49f-PE, CD34-ECD, CD38-PC5.5, CD81-APC, CD22-APC-AF700, CD10-APC-AF750, CD123-PB, CD45 Kro) and subsequently analyzed with both conventional sequential gating method and Kaluza radar plot. MRD was defined as a cell cluster >10 events falling outside the normal maturation "zone" defined by 10 reference BM. The conventional/sequential gating method was composed of 16 dual-parameter dot plots gated on CD19+ events which were further categorized by gating on a CD10/CD34 plot to identify all possible B-cell precursors, which were finally analyzed for MRD. In the novel Kaluza analysis software, all CD19 + events were gated and sent to a single 9-parameter radar plot, resulting in only a total of 2 plots to be evaluated for MRD detection. The total analysis time used for each case was measured.
Results: There were 31 MRD-ve and 19 MRD+ve BM, which showed complete qualitative or quantitative agreement between the two methods. The detected MRD ranges from 0.01 to 2.06% (mean = 0.39%) and 0.01 to 1.81% (mean = 0.34%) for the conventional sequential gating method and the novel 9-parameter Kaluza radar plot method, respectively. Both methods show good correlation (r=0.9989, p<0.0001). Although there is no difference of MRD value detected by conventional and Kaluza method (Wilcoxon test; p>0.05), the expert analysis time was 30 minutes on average for the conventional/sequential method and 5 min on average for the Kaluza radar plot method.
Conclusions: Using a single 10-color tube, the novel 9-parameter Kaluza radar plot method is accurate for detection of MRD in B-ALL at the standard detection limit of 0.01% and comparable to the conventional/sequential method. Notably, however, the novel Kaluza radar plot method significantly reduces the complexity and turnaround time of analysis of B-ALL MRD compared to conventional/sequential gating strategies in terms of both analysis template building and daily case analysis.
Wednesday, March 6, 2013 9:30 AM
Poster Session V # 239, Wednesday Morning