3D CNN-based Deep Learning Model-based Explanatory Prognostication in Patients with Multiple Myeloma using Whole-body MRI.

Although magnetic resonance imaging (MRI) data of patients with multiple myeloma (MM) are used to predict prognosis, few reports have applied artificial intelligence (AI) techniques for this purpose. We aimed to analyze whole-body diffusion-weighted MRI data using three-dimensional (3D) convolutional neural networks (CNNs) and Gradient-weighted Class Activation Mapping (Grad-CAM), an explainable AI, to predict prognosis and explore the factors involved in prediction. We retrospectively analyzed the MRI data of a total of 142 patients with MM obtained from two medical centers. We defined the occurrence of progressive disease after MRI evaluation within 12 months as a poor prognosis and constructed a 3D CNN-based deep learning model to predict prognosis. Images from 111 cases were used as the training and internal validation data; images from 31 cases were used as the external validation data. Internal validation of the AI model with stratified 5-fold cross-validation resulted in a significant difference in progression-free survival (PFS) between good and poor prognostic cases (2-year PFS, 91.2% versus [vs.] 61.1%, P = 0.0002). The AI model clearly stratified good and poor prognostic cases in the external validation cohort (2-year PFS, 92.9% vs. 55.6%, P = 0.004), with an area under the receiver operating characteristic curve of 0.804. According to Grad-CAM, the MRI signals of the spleen and bones of the vertebrae and pelvis contributed to prognosis prediction. This study is the first to show that image analysis of whole-body MRI using a 3D CNN without any other clinical data is effective in predicting the prognosis of patients with MM.

Familial immune-mediated aplastic anaemia in six different families.

We studied the pathophysiology of aplastic anaemia (AA) in six different pairs of relatives without a family history of hematologic disorders or congenital AA. Five and four of the six pairs shared the HLA-DRB1*15:01 and B*40:02 alleles, respectively. Glycosylphosphatidylinositol-anchored protein-deficient blood cells were detected in eight of the 10 patients evaluated. In a mother-daughter pair from one family, flow cytometry detected leukocytes lacking HLA-A2 due to loss of heterogeneity in chromosome 6p. Whole-exome sequencing of the family pair revealed a missense mutation in MYSM1. These results suggest that genetic inheritance of immune traits might underlie familial AA in some patients.

Eight-color multiparameter flow cytometry (EuroFlow-NGF) is as sensitive as next-generation sequencing in detecting minimal/measurable residual disease in autografts of patients with multiple myeloma.

The prognostic value of minimal/measurable residual disease (MRD) detection in autografts of patients with multiple myeloma (MM) in an autologous stem-cell transplantation setting has been reported. Next-generation flow (NGF) cytometry has lower sensitivity (2 × 10-6) to detect MRD than next-generation sequencing (NGS) (<10-6). We compared the clinical value of high-sensitivity NGF (cutoff: <10-6) and NGS (cutoff: 10-6) for the detection of MRD in the cryopreserved autografts of 49 patients with newly diagnosed MM. The sensitivity test using frozen/thawed autografts revealed a strong correlation among MRD levels of 5 × 10-7 and 1 × 10-4 (r = 0.9997, p < 0.0001) when an adequate number of cells were analyzed. Autograft MRD levels determined using NGF and NGS were highly correlated (r = 0.811, p < 0.0001). MRD-negative patients identified with NGF (cutoff: <10-6) showed significantly longer progression-free survival (PFS) than MRD-positive patients (p = 0.026). The PFS of MRD-negative patients determined by NGS (cutoff: 10-6) was similar to that determined by NGF. These results show that the high-sensitivity NGF method can assess MRD in frozen/thawed autografts, and its prognostic value is comparable to that of NGS.

Measurable Residual Disease Assessment Using Next-Generation Flow in Patients With Relapsed and Refractory Multiple Myeloma Treated With a Combination of Carfilzomib, Lenalidomide, and Dexamethasone.

BACKGROUND/AIM: Carfilzomib, lenalidomide, and dexamethasone (KRD) therapy is widely used for patients with relapse/refractory multiple myeloma (RRMM). However, the response in patients who underwent assessment for measurable residual disease (MRD) has not been elucidated in a prospective study. We aimed to clarify the response rate and outcome of KRD therapy in patients in RRMM, including those with MRD. PATIENTS AND METHODS: Twenty-one consecutive RRMM patients treated with KRD at 4 Japanese Centers between September 2016 and October 2018 were enrolled and assessed for MRD in the bone marrow (cut-off: 1×10-5) using the EuroFlow-next-generation flow (NGF) method. RESULTS: The median number of therapy lines before KRD was 3 (range=1-6), and the median number of KRD cycles was 4 (range=1-22). As the best overall response post-KRD therapy, 52% (11/21) of patients achieved a MRD negative complete response, 71% (15/21) achieved stringent complete response/complete response, and 14% (3/21) achieved a very good partial response. MRD negativity was achieved in 12 of 16 (75%) and 14 of 21 (67%) patients during and after KRD treatment, respectively. The 2-year progression-free survival and overall survival from the start of KRD therapy were 100% and 100%, respectively, in MRD-positive cases and 88% and 100%, respectively, in MRD-negative cases (median follow-up=1.8 years). Grade 3/4 toxicities were reported in 15 patients (71%), with thrombocytopenia being the most frequent toxicity (6 patients, 29%). CONCLUSION: This is the first study that prospectively assessed MRD of patients with RRMM after KRD therapy. KRD treatment achieved a high MRD negativity rate and good outcomes with manageable toxicities.

Hematopoietic stem progenitor cells with malignancy-related gene mutations in patients with acquired aplastic anemia are characterized by the increased expression of CXCR4.

The phenotypic changes in hematopoietic stem progenitor cells (HSPCs) with somatic mutations of malignancy-related genes in patients with acquired aplastic anemia (AA) are poorly understood. As our initial study showed increased CXCR4 expression on HLA allele-lacking (HLA[-]) HSPCs that solely support hematopoiesis in comparison to redundant HLA(+) HSPCs in AA patients, we screened the HSPCs of patients with various types of bone marrow (BM) failure to investigate their CXCR4 expression. In comparison to healthy individuals (n = 15, 12.3%-49.9%, median 43.2%), the median CXCR4+ cell percentages in the HSPCs of patients without somatic mutations were low: 29.3% (14.3%-37.3%) in the eight patients without HLA(-) granulocytes, 8.8% (4.1%-9.8%) in the five patients with HLA(-) cells accounting for >90% of granulocytes, and 7.8 (2.1%-8.7%) in the six patients with paroxysmal nocturnal hemoglobinuria. In contrast, the median percentage was much higher (78% [61.4%-88.7%]) in the five AA patients without HLA(-) granulocytes possessing somatic mutations (c-kit, t[8;21], monosomy 7 [one for each], ASXL1 [n = 2]), findings that were comparable to those (66.5%, 63.1%-88.9%) in the four patients with advanced myelodysplastic syndromes. The increased expression of CXCR4 may therefore reflect intrinsic abnormalities of HSPCs caused by somatic mutations that allow them to evade restriction by BM stromal cells.

The effectiveness of immunosuppressive therapy in patients with aplastic anaemia secondary to chemoradiotherapy for cancers.

The outcome of immunosuppressive therapy (IST) and prognosis in patients with aplastic anaemia (AA) secondary to chemotherapy or radiotherapy for cancers remains unknown. A total of 43 of 2559 patients with AA referred to our hospital had previously received chemoradiotherapy for various types of solid tumours (n = 25) or haematological malignancies (n = 18). Their cancer status was complete remission (CR) in 27, non-CR in 13, and unknown in three. Small populations of glycosylphosphatidylinositol-anchored protein-deficient [GPI(-)] granulocytes were detected in 16 patients (37·2%). Of 18 patients who were treated with IST, 50% improved regardless of the presence of GPI(-) cells. The overall survival (OS) rate was significantly higher in patients with a history of solid tumours patients than in those of haematological malignancies (median OS, 87 vs. 11 months, P = 0·0003), and in patients treated with IST than in those of untreated patients (median OS, 115 vs. 20 months, P = 0·028). Cancer aggravation occurred in two of four patients who were treated with IST while in non-CR of their original cancers. Progression to myelodysplastic syndromes was observed in two patients not possessing GPI(-) cells. IST should thus be considered for patients with AA secondary to chemoradiotherapy for cancers, particularly when their original solid tumours are in CR.

Comparison of minimal residual disease detection in multiple myeloma between the DuraClone and EuroFlow methods.

In this study, the minimal residual disease (MRD) levels in patients with multiple myeloma (MM) were assessed by comparing the new 8-color single-tube multiparameter flow cytometry method (DuraClone), which reduces the cost of antibodies and labor burden of laboratories, with the EuroFlow next-generation flow (NGF) method. A total of 96 samples derived from 69 patients with MM were assessed to determine the total cell acquisition number (tCAN), percentages of total and normal plasma cells (PCs), and MRD levels using two methods. We found that the tCAN was significantly higher with EuroFlow-NGF than with DuraClone (median 8.6 × 106 vs. 5.7 × 106; p < 0.0001). In addition, a significant correlation in the MRD levels between the two methods was noted (r = 0.92, p < 0.0001). However, in the qualitative analysis, 5.2% (5/96) of the samples showed discrepancies in the MRD levels. In conclusion, the DuraClone is a good option to evaluate MRD in multiple myeloma but it should be used with caution.

Hematopoietic stem progenitor cells lacking HLA differ from those lacking GPI-anchored proteins in the hierarchical stage and sensitivity to immune attack in patients with acquired aplastic anemia.

To characterize glycosylphosphatidylinositol-anchored protein-deficient (GPI[-]) and HLA-class I allele-lacking (HLA[-]) hematopoietic stem progenitor cells (HSPCs) in acquired aplastic anemia (AA), we studied the peripheral blood (PB) of 56 AA patients in remission who possessed both (n = 13, Group A) or either GPI(-) (n = 34, Group B) and HLA(-) (n = 9, Group C) cell populations. Seventy-seven percent (10/13) of Group A had HLA(-) cells in all lineages of PB cells, including platelets, while only 23% (3/13) had GPI(-) cells in all lineages, and the median percentage of HLA(-) granulocytes in the total granulocytes (21.2%) was significantly higher than that of GPI(-) granulocytes (0.28%, P < 0.05). The greater lineage diversity in HLA(-) cells than in GPI(-) cells was also seen when Group B and Group C were compared. Longitudinal studies of seven patients in Group A showed a gradual decrease in the percentage of HLA(-) granulocytes, with a reciprocal increase in the GPI(-) granulocytes in four patients responding to cyclosporine (CsA) and an increase in the HLA(-) granulocytes with a stable or declining GPI(-) granulocytes in three patients in sustained remission off CsA therapy. These findings suggest that HLA(-) HSPCs differ from GPI(-) HSPCs in the hierarchical stage and sensitivity to immune attack in AA.

A frequent nonsense mutation in exon 1 across certain HLA-A and -B alleles in leukocytes of patients with acquired aplastic anemia.

Leukocytes that lack HLA allelic expression are frequently detected in patients with acquired aplastic anemia (AA) who respond to immunosuppressive therapy (IST), although the exact mechanisms underlying the HLA loss and HLA allele repertoire likely to acquire loss-of-function mutations are unknown. We identified a common nonsense mutation at position 19 (c.19C>T, p.R7X) in exon 1 (Exon1mut) of different HLA-A and -B alleles in HLA-lacking granulocytes from AA patients. A droplet digital PCR (ddPCR) assay capable of detecting as few as 0.07% Exon1mut HLA alleles in total DNA revealed the mutation was present in 29% (101/353) of AA patients, with a median allele frequency of 0.42% (range, 0.071% to 21.3%). Exon1mut occurred in only 12 different HLA-A (n=4) and HLA-B (n=8) alleles, including B*40:02 (n=31) and A*02:06 (n=15), which correspond to 4 HLA supertypes (A02, A03, B07, and B44). The percentages of patients who possessed at least one of these 12 HLA alleles were significantly higher in the 353 AA patients (92%, P.

Resistance of KIR Ligand-Missing Leukocytes to NK Cells In Vivo in Patients with Acquired Aplastic Anemia.

The loss of killer cell Ig-like receptor ligands (KIR-Ls) due to the copy number-neutral loss of heterozygosity of chromosome 6p (6pLOH) in leukocytes of patients with acquired aplastic anemia (AA) may alter the susceptibility of the affected leukocytes to NK cell killing in vivo. We studied 408 AA patients, including 261 who were heterozygous for KIR-Ls, namely C1/C2 or Bw6/Bw4, for the presence of KIR-L-missing [KIR-L(-)] leukocytes. KIR-L(-) leukocytes were found in 14 (5.4%, C1 [n = 4], C2 [n = 3], and Bw4 [n = 7]) of the 261 patients, in whom corresponding KIR(+) licensed NK cells were detected. The incidence of 6pLOH in the 261 patients (18.0%) was comparable to that in 147 patients (13.6%) who were homozygous for KIR-L genes. The percentages of HLA-lacking granulocytes (0.8-50.3%, median 15.2%) in the total granulocytes of the patients with KIR-L(-) cells were significantly lower than those (1.2-99.4%, median 55.4%) in patients without KIR-L(-) cells. KIR2DS1 and KIR3DS1 were only possessed by three of the 14 patients, two of whom had C2/C2 leukocytes after losing C1 alleles. The expression of the KIR3DS1 ligand HLA-F was selectively lost on KIR-L(-) primitive hematopoietic stem cells derived from 6pLOH(+) induced pluripotent stem cells in one of the KIR3DS1(+) patients. These findings suggest that human NK cells are able to suppress the expansion of KIR-L(-) leukocytes but are unable to eliminate them partly due to the lack of activating KIRs on NK cells and the low HLA-F expression level on hematopoietic stem cells in AA patients.

Correction to: Comparison of minimal residual disease detection in multiple myeloma by SRL 8-color single-tube and EuroFlow 8-color 2-tube multiparameter flow cytometry.

The authors would like to correct the error in the publication of the original article. The corrected detail is given below for your reading.

Comparison of minimal residual disease detection in multiple myeloma by SRL 8-color single-tube and EuroFlow 8-color 2-tube multiparameter flow cytometry.

We sought to determine the efficacy of a new, inexpensive, single-tube 8-color multiparameter flow cytometry (MFC) method (SRL-Flow), which is based on the EuroFlow next-generation flow (NGF) (tube 2 only), to assess minimal residual disease (MRD)-negative status. MRD-negative status is considered a treatment milestone in multiple myeloma (MM). We used 45 bone marrow samples from patients with MM, including 11 cases treated with anti-CD38 monoclonal antibody. The SRL-Flow sample preparation protocol was identical to that of EuroFlow-NGF. The antibody panel for SRL-Flow was as follows: CD138V450/CD27V500/CD38ME (multiepitope)FITC/CD56PE/CD45PerCP-Cy5.5/CD19PE-Cy7/cytoplasmic (Cy) immunoglobulin (Ig) κAPC/CyIgλAPC-H7. To identify abnormal plasma cells (aPCs) of patients with MM who received anti-CD38 monoclonal antibody, we used a panel of anti-CD45 and anti-CD138 antibodies (Abs) rather than a panel of anti-CD45 and anti-CD38 Abs. We comparatively analyzed the total nucleated cell numbers, total PC levels, and MRD levels between the SRL-Flow and EuroFlow-NGF. High correlations (r > 0.9) in total PC and MRD levels were noted among SRL-Flow, original EuroFlow-NGF (2 tubes), and EuroFlow-NGF (tube 2 only), suggesting that SRL-Flow is an inexpensive (< $200 USD/sample as of January of 2019) alternative to EuroFlow-NGF (< $350 USD/sample) for assessing MRD in MM.