Long-Term Thymic Function and Reconstitution of the T Cell Compartment after T Cell-Replete Haplo-Identical Allografting

INTRODUCTION Post-transplant cyclophosphamide (PTCY) has expanded the application of haploidentical stem cell transplantation (haplo-HSCT). Thymic function may play a pivotal role in long-term clinical outcomes. OBJECTIVES To evaluate the kinetics of long-term immune thymus-dependent reconstitution after PTCY haplo-HSCT. METHODS Twenty-nine patients (median age 53) underwent T-cell replete haplo-HSCT with PTCY. Blood samples were collected before conditioning and at 1, 3, 6, 12, 18, 24 months after transplantation. Analyses of CD4 and CD8 T-cell subsets by flow-cytometry were correlated by generalized linear models with Real-Time PCR quantification of signal joint T-cell receptor excision DNA circles (sjTRECs), specific marker of naive T-cells thymopoiesis. A) Naive; b) central; c) memory; and d) revertant CD4 and CD8 T-cells were defined as follows: a) CD45RA+CD62L+; b) CD45RO+CD62L+; c) CD45RO+CD27-; and d) CD45RA+/45RO+, respectively. SjTRECs real-time PCR was performed on genomic DNA (100 ng) extracted from sorted CD4 and CD8 T-cells. RESULTS Following PTCY induced T-cell depletion, a constant gradual increase in absolute numbers of all CD4 and CD8 T cell subsets and of sjTRECs copies from the first month up to two years post-transplant was observed ( Figure 1 ). Overall, at two years, CD4 and CD8 T-cell levels and sjTRECs levels were however lower than those observed in healthy donors. sjTRECs kinetics was associated with the increase in naive T-cells (overall, p CONCLUSIONS Active thymic function despite age-dependent involution, substantially contributes to T-cell reconstitution after haplo-HSCT. Chronic GVHD and older age are however significantly correlated with lower thymic activity. Overall, lower production of sjTRECs after haplo-HSCT as compared after HLA identical sibling HSCT may partly be due to a higher degree of "mismatching" of MHC molecules during thymic re-education

Minimal residual disease after transplantation or lenalidomide-based consolidation in myeloma patients: a prospective analysis

We analyzed 50 patients who achieved at least a very good partial response in the RV-MM-EMN-441 study. Patients received consolidation with autologous stem-cell transplantation (ASCT) or cyclophosphamide-lenalidomide-dexamethasone (CRD), followed by Lenalidomide-based maintenance. We assessed minimal residual disease (MRD) by multi-parameter flow cytometry (MFC) and allelic-specific oligonucleotide real-time quantitative polymerase chain reaction (ASO-RQ-PCR) after consolidation, after 3 and 6 courses of maintenance, and thereafter every 6 months until progression. By MFC analysis, 19/50 patients achieved complete response (CR) after consolidation, and 7 additional patients during maintenance. A molecular marker was identified in 25/50 patients, 4/25 achieved molecular-CR after consolidation, and 3 additional patients during maintenance. A lower MRD value by MFC was found in ASCT patients compared with CRD patients (p = 0.0134). Tumor burden reduction was different in patients with high-risk vs standard-risk cytogenetics (3.4 vs 5.2, ln-MFC; 3 vs 6 ln-PCR, respectively) and in patients who relapsed vs those who did not (4 vs 5, ln-MFC; 4.4 vs 7.8 ln-PCR). MRD progression anticipated clinical relapse by a median of 9 months while biochemical relapse by a median of 4 months. MRD allows the identification of a low-risk group, independently of response, and a better characterization of the activity of treatments

Prospective evaluation of minimal residual disease in the phase II FORTE trial: a head-to-head comparison between multiparameter flow cytometry and next-generation sequencing

Background: Limited data are available on the concordance between multiparameter flow cytometry (MFC) and next-generation sequencing (NGS) for minimal residual disease (MRD) detection in a large trial for multiple myeloma (MM) patients. Methods: MRD was explored in the FORTE trial for transplant-eligible MM patients randomised to three carfilzomib-based induction-intensification-consolidation treatments and carfilzomib-lenalidomide (KR) vs R maintenance. MRD was assessed by 8-colour 2nd-generation flow cytometry in patients with ≥very good partial response before maintenance. NGS was performed in case of suspected complete response (CR) in a correlative subanalysis. Biological/prognostic concordance between MFC and NGS, conversion to MRD negativity during maintenance, and 1-year/2-year sustained MRD negativity were explored. Findings: Between September 28, 2015 and December 22, 2021, 2020 samples were available for MFC and 728 for the simultaneous MFC/NGS correlation in the “suspected CR population”. Median follow-up was 62 months. Biological agreement was 87% at the 10−5 and 83% at the 10−6 cut-offs. A remarkable prognostic concordance was observed: hazard ratios in MFC-MRD and NGS-MRD-negative vs -positive patients were 0.29 and 0.27 for progression-free survival (PFS) and 0.35 and 0.31 for overall survival, respectively (p < 0.05). During maintenance, 4-year PFS was 91% and 97% in 1-year sustained MFC-MRD-negative and NGS-MRD-negative patients (10−5), respectively, and 99% and 97% in 2-year sustained MFC-MRD-negative and NGS-MRD-negative patients, regardless of treatment received. The conversion rate from pre-maintenance MRD positivity to negativity during maintenance was significantly higher with KR vs R both by MFC (46% vs 30%, p = 0.046) and NGS (56% vs 30%, p = 0.046). Interpretation: The significant biological/clinical concordance between MFC and NGS at the same sensitivity suggests their possible use in the evaluation of one of the currently strongest predictors of outcome. Funding: Amgen, Celgene/Bristol Myers Squibb, Multiple Myeloma Research Foundation

SILK-TV: Secret information leakage from keystroke timing videos

Shoulder surfing attacks are an unfortunate consequence of entering passwords or PINs into computers, smartphones, PoS terminals, and ATMs. Such attacks generally involve observing the victim\u2019s input device. This paper studies leakage of user secrets (passwords and PINs) based on observations of output devices (screens or projectors) that provide \u201chelpful\u201d feedback to users in the form of masking characters, each corresponding to a keystroke. To this end, we developed a new attack called Secret Information Leakage from Keystroke Timing Videos (SILK-TV). Our attack extracts inter-keystroke timing information from videos of password masking characters displayed when users type their password on a computer, or their PIN at an ATM or PoS. We conducted several studies in various envisaged attack scenarios. Results indicate that, while in some cases leakage is minor, it is quite substantial in others. By leveraging inter-keystroke timings, SILK-TV recovers 8-character alphanumeric passwords in as little as 19 attempts. However, when guessing PINs, SILK-TV yields no substantial speedup compared to brute force. Our results strongly indicate that secure password masking GUIs must consider the information leakage identified in this paper

Targeted locus amplification to detect molecular markers in mantle cell and follicular lymphoma

Minimal residual disease (MRD) monitoring by PCR methods is a strong and standardized predictor of clinical outcome in mantle cell lymphoma (MCL) and follicular lymphoma (FL). However, about 20% of MCL and 40% of FL patients lack a reliable molecular marker, being thus not eligible for MRD studies. Recently, targeted locus amplification (TLA), a next-generation sequencing (NGS) method based on the physical proximity of DNA sequences for target selection, identified novel gene rearrangements in leukemia. The aim of this study was to test TLA in MCL and FL diagnostic samples lacking a classical, PCR-detectable, t(11; 14) MTC (BCL1/IGH), or t(14; 18) major breakpoint region and minor cluster region (BCL2/IGH) rearrangements. Overall, TLA was performed on 20 MCL bone marrow (BM) or peripheral blood (PB) primary samples and on 20 FL BM, identifying a novel BCL1 or BCL2/IGH breakpoint in 16 MCL and 8 FL patients (80% and 40%, respectively). These new breakpoints (named BCL1-TLA and BCL2-TLA) were validated by ASO primers design and compared as MRD markers to classical IGH rearrangements in eight MCL: overall, MRD results by BCL1-TLA were superimposable (R Pearson = 0.76) to the standardized IGH-based approach. Moreover, MRD by BCL2-TLA reached good sensitivity levels also in FL and was predictive of a primary refractory case. In conclusion, this study offers the proof of principle that TLA is a promising and reliable NGS-based technology for the identification of novel molecular markers, suitable for further MRD analysis in previously not traceable MCL and FL patients