Key Points• MRD assessment by sequencing is prognostic of TTP and OS in multiple myeloma patients.• Among patients in complete response, MRD assessment by sequencing enables identification of 2 distinct subgroups with different TTP.We assessed the prognostic value of minimal residual disease (MRD) detection in multiple myeloma (MM) patients using a sequencing-based platform in bone marrow samples from 133 MM patients in at least very good partial response (VGPR) after front-line therapy.Deep sequencing was carried out in patients in whom a high-frequency myeloma clone was identified and MRD was assessed using the IGH-VDJ H , IGH-DJ H , and IGK assays. The results were contrasted with those of multiparametric flow cytometry (MFC) and allelespecific oligonucleotide polymerase chain reaction (ASO-PCR).

T cells are involved in the early identification and clearance of viral infections and also support the development of antibodies by B cells. This central role for T cells makes them a desirable target for assessing the immune response to SARS-CoV-2 infection. Here, we combined two high-throughput immune profiling methods to create a quantitative picture of the T-cell response to SARS-CoV-2. First, at the individual level, we deeply characterized 3 acutely infected and 58 recovered COVID-19 subjects by experimentally mapping their CD8 T-cell response through antigen stimulation to 545 Human Leukocyte Antigen (HLA) class I presented viral peptides (class II data in a forthcoming study). Then, at the population level, we performed T-cell repertoire sequencing on 1,015 samples (from 827 COVID-19 subjects) as well as 3,500 controls to identify shared "public" T-cell receptors (TCRs) associated with SARS-CoV-2 infection from both CD8 and CD4 T cells. Collectively, our data reveal that CD8 T-cell responses are often driven by a few immunodominant, HLA-restricted epitopes. As expected, the T-cell response to SARS-CoV-2 peaks about one to two weeks after infection and is detectable for several months after recovery. As an application of these data, we trained a classifier to diagnose SARS-CoV-2 infection based solely on TCR sequencing from blood samples, and observed, at 99.8% specificity, high early sensitivity soon after diagnosis (Day 3-7 = 83.8% [95% CI = 77.6-89.4]; Day 8-14 = 92.4% [87.6-96.6]) as well as lasting sensitivity after recovery (Day 29+/convalescent = 96.7% [93.0-99.2]). These results demonstrate an approach to reliably assess the adaptive immune response both soon after viral antigenic exposure (before antibodies are typically detectable) as well as at later time points. This blood-based molecular approach to characterizing the cellular immune response has applications in vaccine development as well as clinical diagnostics and monitoring.

We describe the establishment and current content of the ImmuneCODE™ database, which includes hundreds of millions of T-cell Receptor (TCR) sequences from over 1,400 subjects exposed to or infected with the SARS-CoV-2 virus, as well as over 135,000 high-confidence SARS-CoV-2-specific TCRs. This database is made freely available, and the data contained in it can be downloaded and analyzed online or offline to assist with the global efforts to understand the immune response to the SARS-CoV-2 virus and develop new interventions.

• The incidence of mutations within the MAPK pathway, the CRBN pathway, and TP53 is significantly increased in drug-refractory MM.• Mutations in CRBN might contribute to IMiD resistance in drug-refractory MM.In this study, targeted sequencing to screen 50 multidrug refractory multiple myeloma (rMM) patients was performed by using the Multiple Myeloma Mutation Panel. Patients were pretreated with both immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs), and 88%, 78%, and 68% were refractory to an IMiD, a PI, or both, respectively. The majority of patients had progressive (82%) or refractory (78%) disease immediately before sampling, with 43% being IMiD refractory and 46% being PI refractory in the most recent line of therapy. Compared with newly diagnosed MM, an increased prevalence of mutations in the Ras pathway genes KRAS, NRAS, and/or BRAF (72%), as well as TP53 (26%), CRBN (12%), and CRBN pathway genes (10%) was observed. Longitudinal analyses performed in 3 patients with CRBN mutations at time of IMiD resistance confirmed that these mutations were undetectable at earlier, IMiD-sensitive time points. Furthermore, the functional introduction of these mutations in MM cells conferred lenalidomide resistance in vitro. These data indicate a differential genetic landscape in rMM associated with drug response. (Blood. 2016;128(9):1226-1233

Despite an increasing number of approved therapies, multiple myeloma (MM) remains an incurable disease and only a small number of patients achieve prolonged disease control. Some genes have been linked with response to commonly used anti-MM compounds, including immunomodulators (IMiDs) and proteasome inhibitors (PIs). In this manuscript, we demonstrate an increased incidence of acquired proteasomal subunit mutations in relapsed MM compared to newly diagnosed disease, underpinning a potential role of point mutations in the clonal evolution of MM. Furthermore, we are first to present and functionally characterize four somatic PSMB5 mutations from primary MM cells identified in a patient under prolonged proteasome inhibition, with three of them affecting the PI-binding pocket S1. We confirm resistance induction through missense mutations not only to Bortezomib, but also, in variable extent, to the next-generation PIs Carfilzomib and Ixazomib. In addition, a negative impact on the proteasome activity is assessed, providing a potential explanation for later therapy-induced eradication of the affected tumor subclones in this patient.

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Cereblon (CRBN), a target of immunomodulatory drugs (IMiD), forms the CRL4 CRBN E3 ubiquitin ligase (CRL4) complex with DDB1, CUL4B and ROC1. 1,2 Under the influence of IMiD, CRL4 polyubiquitinates and thus depletes the transcription factors IKZF1 and IKZF3, resulting in cytotoxicity to multiple myeloma (MM) cells. In vitro, CRBN and IKZF1/3 mutations affecting the CRBN-lenalidomide binding site (degron) cause drug resistance to IMiD. [3][4][5] We hypothesized that mutations in the other components of the CRL4 complex and its targets, Ikaros and Aiolos, likewise interfere with ubiquitin ligase activity, thus contributing to resistance to IMiD. In order to select the most promising patient-derived candidate mutations for functional validation, we first generated a comprehensive overview of point mutations

Key Points Clonal PCs in AL have similar phenotypic and CNA profiles as those in MM, but their transcriptome is similar to that of normal PCs. First-ever WES in AL amyloidosis reveals potential lack of a unifying mutation.