Ferrante Martina, Furlan Daniela, Zibellini Silvia, Borriero Michela, Candido Chiara, Sahnane Nora, Uccella Silvia, Genuardi Elisa, Alessandria Beatrice, Bianchi Benedetta, Mora Barbara, Grimaldi Daniele, Defrancesco Irene, Jiménez Cristina, Cavallo Federica, Ferrero Dario, Dogliotti Irene, Merli Michele, Varettoni Marzia, Ferrero Simone, Drandi Daniela
Department of Molecular Biotechnology and Health Sciences, Hematology Division, University of Torino, 10100 Torino, Italy.
Department of Medicine and Surgery, University of Insubria, 21100 Varese, Italy.
Diagnostics (Basel). 2021 Apr 26;11(5):779. doi: 10.3390/diagnostics11050779.
In IgM monoclonal gammopathies MYD88 is a prognostic and predictive biomarker of therapy response. MYD88 detection is mainly performed by allele-specific quantitative PCR (ASqPCR), however recently, droplet digital PCR (ddPCR) has been proved to be suitable for MYD88 screening and minimal residual disease monitoring (MRD). This study compared ASqPCR and ddPCR to define the most sensitive method for MYD88 detection in bone marrow (BM), peripheral blood (PB) sorted or unsorted CD19+ cells, and in plasma cell-free DNA (cfDNA). Overall, the analysis showed a good concordance rate (74%) between the two methods, especially in BM samples, while discordances (26%) were mostly in favor of ddPCR (ddPCR+ vs. ASqPCR-) and were particularly evident in samples with low mutational burden, such as PB and cfDNA. This study highlights ddPCR as a feasible approach for MYD88 detection across different specimen types (including cfDNA). Interestingly, its high sensitivity makes CD19+ selection dispensable. On the other hand, our results showed that MYD88 detection on PB samples, especially with ASqPCR, is suboptimal for screening and MRD analysis. Finally, significantly different MYD88 mutational levels observed between Waldenström Macroglobulinemia and IgM monoclonal gammopathy of undetermined significance patients suggest the need for further studies in order to identify possible correlations between mutational levels and risk of progression to Waldenström.
在IgM单克隆丙种球蛋白病中，MYD88是治疗反应的预后和预测生物标志物。MYD88检测主要通过等位基因特异性定量PCR（ASqPCR）进行，然而最近，液滴数字PCR（ddPCR）已被证明适用于MYD88筛查和微小残留病监测（MRD）。本研究比较了ASqPCR和ddPCR，以确定在骨髓（BM）、分选或未分选的外周血（PB）CD19+细胞以及浆细胞游离DNA（cfDNA）中检测MYD88的最敏感方法。总体而言，分析表明两种方法之间的一致性率良好（74%），尤其是在BM样本中，而不一致性（26%）大多有利于ddPCR（ddPCR+ vs. ASqPCR-），并且在突变负担较低的样本（如PB和cfDNA）中尤为明显。本研究强调ddPCR是一种适用于跨不同样本类型（包括cfDNA）检测MYD88的可行方法。有趣的是，其高灵敏度使得CD19+选择变得不必要。另一方面，我们的结果表明，对PB样本进行MYD88检测，尤其是使用ASqPCR，对于筛查和MRD分析并非最佳选择。最后，在华氏巨球蛋白血症和意义未明的IgM单克隆丙种球蛋白病患者之间观察到的MYD88突变水平存在显著差异，这表明需要进一步研究以确定突变水平与进展为华氏巨球蛋白血症风险之间的可能相关性。
