Myeloid Antigens Research Articles

Project Evolve, Evaluation of Lineage Switch (LS), an International Initiative: Preliminary Results Reveal Dismal Outcomes in Patients with LS

Introduction: Lineage switch (LS) refers to the transformation of acute leukemia from one cell lineage to another (e.g., lymphoid (ALL) to myeloid (AML)). This rare phenomenon, distinct from treatment induced malignancy (i.e., t-AML) and mixed phenotype acute leukemia (MPAL), is increasingly being observed following cell surface antigen targeting. Given challenges in the diagnosis and treatment of LS, Project EVOLVE was developed to globally identify cases of LS following immunotherapy. Methods: A protocol and data collection form for this IRB exempt study was widely disseminated to capture deidentified LS case information across multiple centers and cancer consortia. This included collection of data from published reports of LS, with authors contacted to obtain additional information. For this analysis, LS was defined by the emergence of cell-surface markers warranting reclassification of the original leukemia as a different lineage derivation based on the immunophenotype, including cases of AML emerging alongside the original ALL. “Confirmed” LS cases included those where retention of original cytogenetic or molecular aberrations and/or the clonal immunoglobulin rearrangement patterns were verified to confirm the clonal relationship. “Suspected” LS cases included those where samples to confirm clonality marker retention could not be obtained, but the clinical presentation was consistent with LS. The term “transition” was applied when immunophenotypic shifts were transient. Cases with new cytogenetic abnormalities unrelated to the original diagnosis and compatible with t-AML were excluded. Statistical analysis was primarily descriptive. Data cut-off was July 26, 2023. Results: A total of 58 cases were identified, including 19 cases referenced in prior publications. Of the 58, 11 cases were excluded from this initial analysis, including: 4 cases of t-AML, 2 cases of T-ALL to AML, and 5 “transition” cases. Collectively, 47 cases of LS (43 “confirmed”; 4 “suspected”), spanning across 3 continents and 8 countries, were analyzed. (Fig. 1A) Cases included transition from B-ALL to AML in 36 (76.6%) and to MPAL/biphenotypic/ambiguous lineage in 11 (23.4%). Two likely had MPAL at diagnosis and a third with chronic myeloid leukemia. The median age at initial diagnosis was 8.4 years (range, 1 day-76.5 years); median age at LS presentation was 11.0 years (range 0.4-77.3 years). Twenty-three (48.9%) were male and 19 (40.4%) had prior stem cell transplant (SCT). Baseline cytogenetics showed KMT2A rearrangement in 27 (57.4%). Baseline myeloid antigen co-expression was seen in 22 of 23 patients with submitted data, but variation in degree of expression across patients and antigens was substantial. The most proximal immunotherapy prior to development of LS was CAR T-cells in 23 (48.9%) and blinatumomab in 24 (51.1%). The median time from the most proximal immunotherapy to development of LS was 1.6 months (range, 7 days-36.5 months). In 7 (29.2%) patients receiving blinatumomab, LS developed during the infusion. LS presented as isolated marrow relapse in 27 (57.4%), isolated CNS in 2 (4.3%), isolated non-CNS extramedullary disease in 3 (6.4%), combined relapse in 14 (29.8%) and unreported in 1. First line treatment for LS was chemotherapy induction in 31 (66.0%), palliative care/no therapy in 8 (17.0%), and alternative therapies in the remaining 8 (17.0%). In 35 (74.5%) patients, remission induction was the goal of first line therapy. Fifteen (31.9%) achieved a complete remission (CR) of whom 2 were treated with palliative intent. Across all patients, 8 (17.0%) are alive in remission, the longest being 4.7 years from LS diagnosis; 2 (4.3%) are alive with active LS and 37 (78.7%) died from LS, their original disease, or complications of treatment of LS (Fig 1B). For those alive in CR (n=8), 7 (87.5%) proceeded to a consolidative SCT for treatment of LS and 1 patient, an octogenarian remains in remission after AML directed therapy. Conclusions: LS is emerging as an important mechanism of immune escape following immunotherapy. Project EVOLVE provides the largest dataset of patients with LS to date. This systematic, international effort reveals substantial complexity and variability in diagnosing and managing LS. Unfortunately, outcomes following LS are grim, underscoring the critical need to identify risk factors of and optimal therapies for this leukemia transformation.

CD33-TIM3 Dual CAR T Cells: Enhancing Specificity While Maintaining Efficacy Against AML

Background: The myeloid associated antigen CD33 is overexpressed in over 88% of Acute myeloid leukemia (AML) patients, making it a suitable target antigen for CAR T cell therapy across different genetic subtypes. Despite the development of clinical trial data, there remains a concern about on-target off-leukemia toxicity. To enhance specificity, we generated dual targeting CAR T cells that target CD33 and/or T-cell immunoglobulin and mucin-domain containing-3 (TIM3). The latter is known to be expressed on LSCs, but not on healthy hematopoietic precursor or stem cells. Notably, TIM3 is recognized for its inhibitory immunomodulatory role further enhancing the suitability of this target antigen. The objective of this research was to explore various CD33 and TIM3 dual-targeting CAR T cells approaches that enhance AML specificity and maintain high anti-AML activity. Methods: The hybridoma technology was used to generate antibodies against TIM3 immunized mice. Antibodies were screened for TIM3 specificity via ELISA and FACS. The anti-TIM3 single-chain variable fragment (scFv) DNA sequence was sequenced from hybridoma cells. Furthermore, the binding ability to TIM3 antigen (PDB ID: 5F71) was evaluated using AlphaFold. The CD33 scFv was derived from Gemtuzumab ozogamicin (clone: hP67.6). ScFv sequences and co-stimulation domains (CD28 or 4-1BB) were cloned into a pMP71 vector. Retrovirus for transduction was produced using the 293Vec-GALV and RD114 retroviral production system. In vitro co-culture assays of CAR T cells and target cells were performed to study the efficacy of CAR T cells. The cytotoxicity against wild-type and TIM3 transduced AML cell lines (THP-1 and OCI-AML3) was assessed by multiparameter flow cytometry (MPFC). The secretion of effector cytokines (IFN-γ, TNF, IL-2) was analyzed via CBA assays. In addition, avidity between CAR T cells and target cells was determined by Z-Movie analyzer. The different CAR constructs were screened for on-target off-tumor toxicity in colony forming unit assays (CFU) using isolated CD34 + hematopoietic stem and progenitor cells (HSPCs) from healthy doners after 14 days. In order to compare CAR constructs regarding long-term efficacy in antigen restimulation assays, CAR T cells were co-cultured with irradiated TIM3 transduced OCI-AML3 every 4 days at an E: T ratio of 1:1 for 24 days. Moreover, CAR T-cell proliferation, checkpoint marker expression and T-cell subset differentiation were analyzed via MPFC. Results: All dual CAR T cells (compound, split, tandem, pooled) were generated with high and robust transduction efficacy (Figure 1A). TIM3-dependent fratricide was not observed during CAR T cell manufacturing. Compared to single antigen targeting CAR T cells, dual CAR T cells showed enhanced cytotoxicity against AML cell lines and primary AML cells (Figure 1B). Moreover, we also observed a strong increase in the secretion of proinflammatory cytokines (IFN-γ and IL-2) and higher avidity of dual CAR T cells. Notably, split CAR T cells demonstrated greater specificity in cocultures directed against mono vs. dual-target antigen expression cell lines. In accordance with these observations, split CAR T cells did not exert on-target off-leukemia toxicity against healthy HSC in CFU assays. In the antigen restimulation assay, we observed that compound CAR T cells exhibited diminished expanding capacity and heightened expression of exhaustion markers in comparison to the other CAR T constructs. Conclusion: We developed multiple CD33 and TIM3 dual CAR T cells using both “AND” and “OR” gating strategies in this study. Our findings revealed that dual CAR T cells provided higher avidity and cytotoxicity compared to single targeting CAR T cells against dual antigen expressing target cells in vitro. Importantly, only the split CAR T constructs demonstrated specific killing of CD33 +TIM3 + cell lines and primary AML cells while sparing HSPCs. Prospectively, compound, tandem, pooled CD33 TIM3 specific CAR T cells might be helpful in a bridge to transplant setting, whereas split CAR T cells might provide a higher safety profile, thereby allowing a transplant independent approach. To advance our concepts, we are currently conducting in vivo experiments in an NSG mouse model.

Early T-Cell Precursor Leukemia: A High-Risk Subtype of Acute Lymphoblastic Leukemia, Single Center Experience in Jordan

Background and ObjectivesEarly T-cell precursor (ETP) acute lymphoblastic leukemia/lymphoma (ALL/LBL) is a newly recognized entity of T-lymphoblastic leukemia/lymphoma. The optimal therapeutic approaches to adult patients are poorly studied. Patients and MethodsWe compared the outcomes of adult's patents with ETP-ALL/LBL who received frontline chemotherapy regimens with other T-ALL/LBL immunophenotypic subtypes. Patients with ETP-ALL/LBL were identified based on CD1a (-), CD8 (-), CD5 (-) (dim), and positivity for 1 or more stem cell or myeloid antigens. ResultsSixty-nine patients were included between the years 2010 and 2021 (19 ETP-T-ALL/LBL; 50 non ETP- T-cell ALL/LBL). The median age was 26 year (IQR: 21, 33). Fifty-six patients presented as ALL, while 16 with lymphoblastic lymphoma. Forty-seven patients achieved complete remission, and 43 were alive at last encounter. The complete remission rate in patients with ETP-ALL/LBL was lower than that of non-ETP-ALL/LBL patients (32% vs. 68%; P = .2), and the MRD at end of induction was significantly higher (26% vs. 6.2%, P < .001), and more likely to receive allo-SCT consolidation in CR1 (95% vs. 40%, P < .001). After a median follow-up of survivors of 48 months (range: 32-74 months), the median overall survival for patients with ETP-ALL/LBL was not reached versus 11.5 months for the non-ETP-ALL/LBL patients (P = .014)). Twenty-six patients receive allo-SCT in CR1. There was no significant difference in overall survival (79% vs. 70%; P = .49) between both transplant-cohorts in both groups. ConclusionETP-ALL/LBL represents a high-risk disease subtype of adult ALL. Novel treatment strategies are needed to improve treatment outcomes in this patient's population

Identifying Suitable Targets for Alzheimer's Disease and Other Eight Common Neurological Disorders Using the Human Plasma Proteome: A Mendelian Randomization Study.

Neurological disorders, such as Alzheimer's disease (AD), comprise a major cause of health-related disabilities in human. However, biomarkers towards pathogenesis or novel targets are still limited. To identify the causality between plasma proteins and the risk of AD and other eight common neurological diseases using a Mendelian randomization (MR) study. Exposure data were obtained from a genome-wide association study (GWAS) of 2,994 plasma proteins in 3,301 healthy adults, and outcome datasets included GWAS summary statistics of nine neurological disorders. Inverse variance-weighted MR method as the primary analysis was used to estimate causal effects. Higher genetically proxied plasma myeloid cell surface antigen CD33 level was found to be associated with increased risk of AD (odds ratio [OR] 1.079, 95% confidence interval [CI] 1.047-1.112, p = 8.39×10-7). We also discovered the causality between genetically proxied elevated prolactin and higher risk of epilepsy (OR = 1.068, 95% CI = 1.034-1.102; p = 5.46×10-5). Negative associations were identified between cyclin-dependent kinase 8 and ischemic stroke (OR = 0.927, 95% CI = 0.896-0.959, p = 9.32×10-6), between neuralized E3 ubiquitin-protein ligase 1 and migraine (OR = 0.914, 95% CI = 0.878-0.952, p = 1.48×10-5), and between Fc receptor-like protein 4 and multiple sclerosis (MS) (OR = 0.929, 95% CI = 0.897-0.963, p = 4.27×10-5). The findings identified MR-level protein-disease associations for AD, epilepsy, ischemic stroke, migraine, and MS.

Structural mechanism of dsDNA recognition by the hMNDA HIN domain: New insights into the DNA-binding model of a PYHIN protein

The hematopoietic interferon-inducible nuclear (HIN) domain of the PYHIN family of proteins recognizes double-stranded DNA (dsDNA) through different dsDNA-binding modes. These modes apparently confer different roles upon these proteins in the regulation of innate immune responses, gene transcription, and apoptosis. Myeloid cell nuclear differentiation antigen (MNDA), a member of the human PYHIN family, binds DNA and regulates gene transcription in monocytes. However, the mechanism of DNA recognition and DNA-binding modes of human MNDA (hMNDA) remain unclear. Here, we determined the crystal structure of the hMNDA–HIN domain in complex with dsDNA at 2.4 Å resolution, and reveal that hMNDA–HIN binds to dsDNA in a sequence-independent manner. Structure and mutation studies indicated that hMNDA–HIN binds to dsDNA through a unique mode, involving two dsDNA-binding interfaces. Interface I exhibits an AIM2-like dsDNA-binding mode, and interface II has a previously unreported mode of dsDNA-binding. These results provide new insights into the DNA-binding modes of this PYHIN protein.

P423 RELAPSE OF ACUTE MYELOID LEUKEMIA WITH CARDIAC INFILTRATION: A CASE REPORT

Abstract We describe the case of a 42–year–old man who presented to the emergency department suffering from asthenia, dyspnea and tachycardia. The patient had been diagnosed, two years earlier, with acute myeloid leukemia (AML), treated with two lines of chemotherapy and allogeneic bone marrow transplantation from a family donor. Atrial fibrillation with rapid ventricular response was documented at the ECG. The echocardiogram showed moderate left ventricular dysfunction in the presence of dishomogeneous thickening of left and right ventricular wall and a severe circumferential pericardial effusion causing cardiac tamponade, with the need of urgent pericardiocentesis. AML relapse was documented at the laboratory tests. The suspected cardiac involvement was investigated with cardiac MRI which documented thickening and diffuse late gadolinium enhancement at the level of the left and right ventricular wall, the interatrial septum and the atria walls. The pericardium and the epicardial fat were also thickened and endowed with contrast enhancement. A lymphocyte assay was performed on pericardial fluid and showed the presence of a blast population (approximately 27% of white blood cells) with variable expression of myeloid antigens. The clinical, radiological and finally immunophenotypic picture therefore concluded with relapse of acute myeloid leukemia with myocardial and pericardial infiltration. Acute myeloid leukemia usually presents with symptoms related to bone marrow failure. Clinically significant cardiac involvement is rare but should be considered when cardiorespiratory symptoms occur. Cardiac manifestations include coronary artery disease, heart failure, conduction disturbances, myocarditis, pericarditis, and pericardial effusion. Understanding the underlying pathophysiology and recognizing potential cardiac manifestations could help in the early diagnosis, evaluation, and treatment of these patients. Echocardiography or cardiac MRI could reveal morphological, structural and signal abnormalities of the cardiac structures and therefore should raise the suspicion of a possible myocardial infiltration by leukemia cells, both in patients with a positive history of leukemia and in those in whom cardiac involvement could represent the first manifestation of a hematological pathology.

Acquired resistance against skin penetration by Strongylodies rattiis dependent on IL-33 expressing APCs

Abstract Interleukin 33 (IL-33) is an alarmin cytokine released from damaged epithelia that is essential for protection against gastrointestinal (GI) helminth (worm) infection, but whether IL-33 serves any role in cutaneous immunity against parasites remains unclear. While epithelial cells are considered the predominant source of IL-33, our recent work demonstrates that CD11c+ myeloid antigen presenting cells can express IL-33 to shape Type 2 immunity. We developed a percutaneous infection model using Strongylodies ratti, a rodent-specific GI helminth, to better understand mechanisms of host protection and the potential role for IL-33. Data show that C57BL/6 mice develop resistance to percutaneous infection upon secondary challenge, but IL-33 deficient mice lack this capacity. Surprisingly, mice with a selective IL-33 deficiency only in myeloid APC (CD11c Cre) also failed to develop secondary resistance to S. ratti, suggesting myeloid-derived IL-33 is essential for cutaneous immunity. Mechanistically, we find that loss of myeloid IL-33 impairs recruitment of gd T cells that express the IL-33 receptor ST2 and gene deficient mice that lack all gd T cells show defective protective immunity against S. ratti. Moreover, we propose that IL-33 drives a noncanonical Type 2 immunity, because mice lacking the Type 2 transcription factor STAT6 (Signal transducer and activator of transcription 6), have no defects in primary or secondary cutaneous immunity. Our work implies that myeloid APCs are a necessary source of IL-33 that drives acquired immunity against helminths, potentially through regulating gd T cell effector function(s). Ongoing studies seek to understand how myeloid APC derived IL-33 controls gd T cells to promote cutaneous immunity. NIH (R01 AI095289 and R01 GM083204) NSF GFRP

Extracorporeal Photopheresis Suppresses Transplant Fibrosis by Inducing Decorin Expression in Alveolar Macrophages.

Extracorporeal Photopheresis Suppresses Transplant Fibrosis by Inducing Decorin Expression in Alveolar Macrophages.

Abstract 3190: ALA-CART induces global transcriptional changes leading to enhanced potency and persistence of CAR T cells against both lymphoid and myeloid acute leukemias

Abstract Chimeric antigen receptor (CAR) T cell therapy has revolutionized cancer treatment, demonstrating clinical success in B-cell malignancies that are refractory to standard therapies. Relapses after CAR therapy has demonstrated the limitations of current CAR T cell therapies to target antigen-low tumors and induce consistent persistence. Furthermore, the success of CAR T cell therapy in B-lineage malignancies has not yet been translated to acute myeloid leukemia (AML). The targeting of myeloid-restricted antigens, such as CD33, with standard 2nd generation CAR T cells has not yielded similar clinical responses as ALL. Therefore, we hypothesize that novel CAR T cell strategies will be required to improve responses in non-B cell malignancies. We identified that CAR T cells inefficiently activate the scaffolding protein LAT in response to low levels of antigen, leading to diminished efficacy. We designed a bicistronic construct consisting of a clinically active 2nd generation CD22-BBz CAR along with a novel Adjunctive LAT Activating CAR incorporating the intracellular signaling domain of LAT (ALA-CART) to overcome this deficiency of signaling in CAR T cells. In xenograft models, 22ALA-CART cells completely eradicated CD22-low leukemia, which is not responsive to standard CD22-BBz CAR T cells. We have extended these findings to CD19-directed ALA-CART cells, which eradicate CD19-low leukemia that is otherwise resistant to standard CD19-BBz CAR T cells. To understand how ALA-CART improves responses to antigen-low leukemia, we evaluated the in vivo potency of ALA-CART relative to 2nd generation CARs and found ALA-CART cells could eradicate ALL in xenograft models at lower doses than standard CAR T cells. RNA-Seq analysis demonstrated global differences in ALA-CART cells in the resting state reflecting a less differentiated state, which corresponded to an enrichment of T stem cell memory cells and enhanced in vivo persistence. Stimulation through the ALA-CART receptor led to widespread changes in transcription factor activity in T cells which were distinct from standard CAR activation, particularly inducing significantly lower interferon response factor activity which has been associated with CAR T cell failure in patients. As strategies targeting myeloid lineage-restricted antigens with 2nd generation CAR T cells have not yet produced the clinical success seen with ALL-directed CAR therapy, we tested whether the ALA-CART platform could improve the activity of CD33-directed CAR T cells. CD33 ALA-CART cells demonstrated improved in vivo potency and exhibited enhanced memory potential like our results with ALL-directed ALA-CART. Thus, through the reversal of signaling deficits intrinsic to 2nd generation CARs, the ALA-CART platform improves the potency and persistence of CAR T cell therapy against both lymphoid and myeloid acute leukemias. Citation Format: Catherine Danis, Lillie Leach, Christopher Ebmeier, Amanda Novak, Etienne Danis, M. Eric Kohler. ALA-CART induces global transcriptional changes leading to enhanced potency and persistence of CAR T cells against both lymphoid and myeloid acute leukemias [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3190.

Cutaneous arteritis with intimal fibrin ring and immature myeloid cell infiltrate: lymphocytic thrombophilic arteritis or histiocytoid polyarteritis nodosa?

The ongoing debate on whether lymphocytic thrombophilic arteritis (LTA) is a separate disease or a type of polyarteritis nodosa (PAN) has yet to be settled. In this study, we analyzed the nature of infiltrating cells in LTA to resolve this controversy. Skin biopsies from five female patients (mean age 29.4years, age range 16-45years) diagnosed with LTA were immunostained for CD3, CD20, CD68, lysozyme, myeloid cell nuclear differentiation antigen, myeloperoxidase, and PU.1. Immunohistochemistry revealed that the majority of mononuclear cells in all five cases were not lymphocytes but myelomonocytic cells. Given that the infiltrating cells are of the myelomonocyte lineage including immature myeloid cells, PAN was deemed the more appropriate diagnosis for the five cases rather than LTA. Whether PAN with immature myeloid cells (histiocytoid PAN) is the same disease as conventional PAN with mature neutrophils requires further investigation.

ETP ALL or mixed phenotype acute leukemia: Diagnostic dilemma in acute leukemia with simultaneous expression of thymic and myeloid markers

Early T precursor acute lymphoblastic leukemia (ETP ALL) is rare and has a characteristic phenotype. Mixed phenotype acute leukemia (MPAL), as per World Health Organization, needs to have two different lineages. On cytochemistry, myeloid lineage is designated by more than 3% blast cells positivity for cytochemical myeloperoxidase (MPO). Flow cytometric analysis of MPO an arbitrary cutoff of 10% has been described in the literature for this purpose by some authors. Many laboratories performing flow cytometric immunophenotyping of hematolymphoid neoplasms do not use cytochemical MPO. The differential diagnosis between ETP ALL with myeloid antigen expression and T/Myeloid MPAL is tricky. Here, we describe a case where in cytochemistry and morphology favor myeloid lineage and flow cytometry findings in isolation favored ETP ALL, thereby highlighting the benefits of cytochemical MPO staining of bone marrow/blood smears in the diagnostic workup for acute leukemia.

Comparison of flowcytometry-based scoring system for the diagnosis of early T precursor-acute lymphoblastic leukemia.

Early T cell precursor-acute lymphoblastic leukemia (ETP-ALL) is a hematolymphoid malignancy where the blasts demonstrate T cell differentiation markers along with stem cell and myeloid antigen expression. The differential diagnosis of ETP-ALL from non-ETP ALL and mixed phenotype acute leukemia is often challenging due to its overlapping immunophenotypic picture with co-expression of myeloid antigens. In this study, we endeavored to describe the immune-phenotype profile of ETP-ALL in our patients and compared the utility of four different scoring systems for better discrimination of these entities. This retrospective analysis included 31 ETP-ALL out of 860 acute leukemia cases consecutively diagnosed at the two tertiary care centers. Flowcytometry-based immunophenotype was reviewed for all the cases, and the utility of four flow-based objective scorings was assessed for the diagnosis of ETP-ALL. Receiver operating curves were drawn to compare the different flow-based scoring systems. The prevalence of ETP-ALL was 40% (n=31/77 T-ALL) in our study group, comprised mainly of adults with a median age of 20 years. The five-marker scoring system had the maximum area under the curve, followed by the seven-marker scoring system. A cut-off of ≥2.5 was more specific (sensitivity: 91%; specificity: 100%), while a score of ≥1.5 was more sensitive but slightly less specific (sensitivity: 94%, specificity: 96%). The WHO criteria for the diagnosis of ETP-ALL should be followed across all laboratories to avoid confusion and for better treatment stratification. Flow-based scoring systems can be objectively employed for better detection of cases.

Study of the Utility of Myeloid Cell Nuclear Differentiation Antigen (MNDA) in the Diagnosis of Marginal Zone Lymphoma.

Myeloid cell nuclear differentiation antigen (MNDA) is normally expressed on myelomonocytic cells and a subset of B lymphocytes. It was found to be differentially expressed between nodal marginal zone lymphoma (MZL) and follicular lymphoma (FL). However, MNDA has not been widely used as a diagnostic marker in clinical practice. To validate its utility, we studied the expression of MNDA by immunohistochemistry in 313 cases of small B-cell lymphomas. Our results showed that MNDA was positive in 77.9% of MZL, 21.9% of mantle cell lymphoma, 28.9% of small lymphocytic lymphoma/chronic lymphocytic leukemia, 2.6% of FL, and 25% of lymphoplasmacytic lymphoma. MNDA positivity varied from 68.0% to 84.0% among the 3 MZL subtypes, with extranodal MZL having the highest percentage. There was a statistically significant difference in MNDA expression between MZL and FL, mantle cell lymphoma, small lymphocytic lymphoma/chronic lymphocytic leukemia, or lymphoplasmacytic lymphoma. CD43 expression was slightly more frequent in MNDA-negative MZL than in MNDA-positive MZL. Combined use of CD43 and MNDA improved the diagnostic sensitivity for MZL from 77.9% to 87.8%. There was a trend of positive correlation between MNDA and p53 in MZL. In conclusion, MNDA is preferentially expressed in MZL among small B-cell lymphomas and it is a useful marker for the differentiation of MZL and FL.

Clinical Characteristics and Prognosis of Secondary Acute Lymphoblastic Leukemia in Patients with Multiple Myeloma during Long-Term Thalidomide Maintenance.

Background: Secondary primary malignancies (SPM) have attracted increasing attention with the application of autologous hematopoietic stem cell transplantation (ASCT) and novel agents in multiple myeloma (MM). Secondary acute lymphoblastic leukemia (sALL) has rarely been reported, and the clinical characteristics and prognosis of sALL have not been described in detail. Methods: We retrospectively enrolled 179 consecutive newly diagnosed multiple myeloma (NDMM) patients undergoing bortezomib-based induction regimens followed by upfront ASCT and maintenance therapy from December 2006 to April 2018 in our center. Results: The median follow-up interval was 69.1 months, and 12 patients (6.7%) developed sALL during maintenance therapy. The median time from the diagnosis of MM to the occurrence of sALL was 51.1 (31.7-91.5) months. All sALL patients received thalidomide as maintenance therapy before the onset of sALL, and the median duration of thalidomide maintenance was 39.5 (24-74) months. The cumulative incidence of sALL was 6.6% and 11.2% at 5 and 10 years after the diagnosis of MM, respectively. All sALL patients presented with a B-cell immunophenotype accompanied by myeloid antigen expression according to flow cytometry analysis, and the BCR/ABL fusion gene was all negative. Only one patient had evidence of active MM, and the other patients were in stable status at the time of the diagnosis of sALL. The prognosis of most sALL patients was very poor, and the median overall survival time was 11.9 (1.1-51.2) months since the diagnosis of sALL. Conclusions: sALL should be considered for MM patients who developed unexplained persistent cytopenia while on long-term thalidomide maintenance treatment, particularly if it has been more than 3 years. With the increasing availability of new drugs for MM, thalidomide may be recommended for no more than 3 years. Sequential allogeneic hematopoietic stem cell transplantation was considered as soon as possible after achieving remission in order to achieve a longer survival.

Oncolytic BHV-1 Is Sufficient to Induce Immunogenic Cell Death and Synergizes with Low-Dose Chemotherapy to Dampen Immunosuppressive T Regulatory Cells.

Immunogenic cell death (ICD) can switch immunologically "cold" tumors "hot", making them sensitive to immune checkpoint inhibitor (ICI) therapy. Many therapeutic platforms combine multiple modalities such as oncolytic viruses (OVs) and low-dose chemotherapy to induce ICD and improve prognostic outcomes. We previously detailed many unique properties of oncolytic bovine herpesvirus type 1 (oBHV) that suggest widespread clinical utility. Here, we show for the first time, the ability of oBHV monotherapy to induce bona fide ICD and tumor-specific activation of circulating CD8+ T cells in a syngeneic murine model of melanoma. The addition of low-dose mitomycin C (MMC) was necessary to fully synergize with ICI through early recruitment of CD8+ T cells and reduced infiltration of highly suppressive PD-1+ Tregs. Cytokine and gene expression analyses within treated tumors suggest that the addition of MMC to oBHV therapy shifts the immune response from predominantly anti-viral, as evidenced by a high level of interferon-stimulated genes, to one that stimulates myeloid cells, antigen presentation and adaptive processes. Collectively, these data provide mechanistic insights into how oBHV-mediated therapy modalities overcome immune suppressive tumor microenvironments to enable the efficacy of ICI therapy.

Quantitative proteomic analysis of human serum using tandem mass tags to predict cardiovascular risks in patients with psoriasis

Although biomarker candidates associated with psoriasis have been suggested, those for predicting the risk of cardiovascular disease (CVD) early in patients with psoriasis are lacking. We aimed to identify candidate biomarkers that can predict the occurrence of CVD in psoriasis patients. We pursued quantitative proteomic analysis of serum samples composed of three groups: psoriasis patients with and those without CVD risk factors, and healthy controls. Age/Sex-matched serum samples were selected and labeled with 16-plex tandem mass tag (TMT) and analyzed using liquid chromatography-mass spectrometry and subsequent verification with ELISA. Of the 184 proteins that showed statistical significance (P-value < 0.05) among the three groups according to TMT-based quantitative analysis, 98 proteins showed significant differences (> 2.0-fold) between the psoriasis groups with and without CVD risk factors. Verification by ELISA revealed that caldesmon (CALD1), myeloid cell nuclear differentiation antigen (MNDA), and zyxin (ZYX) levels were significantly increased in the psoriasis group with CVD risk factors. Further network analysis identified pathways including integrin signaling, which could be related to platelet aggregation, and actin cytoskeleton signaling. Three novel candidates (MNDA, ZYX, and CALD1) could be potential biomarkers for predicting CVD risks in psoriasis patients. We expect these biomarker candidates can be used to predict CVD risk in psoriasis patients in clinical settings although further studies including large validation are needed.

Study on the Relationship between Integrin 2A and Drug Resistance in Chronic Myeloid Leukemia

To explore the expression pattern and clinical significance of Integral membrane protein 2A（ITM2A） in drug resistant patients with chronic myeloid leukemia (CML). The expression of ITM2A in CML was evaluated by qRT-PCR, Western blot and immunocytochemistry. In order to understand the possible biological effects of ITM2A, apoptosis, cell cycle and myeloid differentiation antigen expression of CML cells were detected by flow cytometry after over-expression of ITM2A. The nuderlying molecular mechanism of its biological effect was explored. The expression of ITM2A in bone marrow of CML resistant patients was significantly lower than that of sensitive patients and healthy donors（P<0.05）. The CML resistant strain cell K562R was successfully constructed in vitro. The expression of ITM2A in the resistant strain was significantly lower than that in the sensitive strain(P<0.05). Overexpression of ITM2A in K562R cells increased the sensitivity of K562R cells to imatinib and blocked the cell cycle in G2 phase(P<0.05), but did not affect myeloid differentiation. Mechanistically, up-regulation of ITM2A reduced phosphorylation in ERK signaling (P<0.05). The expression of ITM2A was low in patients with drug resistance of CML, and the low expression of ITM2A may be the key factor of imatinib resistance in CML.

A stem cell epigenome is associated with primary nonresponse to CD19 CAR T cells in pediatric acute lymphoblastic leukemia

AbstractCD19 chimeric antigen receptor T-cell therapy (CD19-CAR) has changed the treatment landscape and outcomes for patients with pre–B-cell acute lymphoblastic leukemia (B-ALL). Unfortunately, primary nonresponse (PNR), sustained CD19+ disease, and concurrent expansion of CD19-CAR occur in 20% of the patients and is associated with adverse outcomes. Although some failures may be attributable to CD19 loss, mechanisms of CD19-independent, leukemia-intrinsic resistance to CD19-CAR remain poorly understood. We hypothesize that PNR leukemias are distinct compared with primary sensitive (PS) leukemias and that these differences are present before treatment. We used a multiomic approach to investigate this in 14 patients (7 with PNR and 7 with PS) enrolled in the PLAT-02 trial at Seattle Children’s Hospital. Long-read PacBio sequencing helped identify 1 PNR in which 47% of CD19 transcripts had exon 2 skipping, but other samples lacked CD19 transcript abnormalities. Epigenetic profiling discovered DNA hypermethylation at genes targeted by polycomb repressive complex 2 (PRC2) in embryonic stem cells. Similarly, assays of transposase-accessible chromatin–sequencing revealed reduced accessibility at these PRC2 target genes, with a gain in accessibility of regions characteristic of hematopoietic stem cells and multilineage progenitors in PNR. Single-cell RNA sequencing and cytometry by time of flight analyses identified leukemic subpopulations expressing multilineage markers and decreased antigen presentation in PNR. We thus describe the association of a stem cell epigenome with primary resistance to CD19-CAR therapy. Future trials incorporating these biomarkers, with the addition of multispecific CAR T cells targeting against leukemic stem cell or myeloid antigens, and/or combined epigenetic therapy to disrupt this distinct stem cell epigenome may improve outcomes of patients with B-ALL.

Immunophenotype of Acute Lymphoblastic Leukemia: The Experience of University Hospital Centre Casablanca - Morocco.

Acute lymphoblastic leukemia (ALL) encompasses a group of lymphoid neoplasms that morphologically and immunophenotypically resemble B-lineage and T-lineage precursor cells. Our objective is to describe the immunophenotypic aspects of acute lymphoblastic leukemia (All) diagnosed by flow cytometry at the hematology laboratory of IBN ROCHD University Hospital Center and to compare them with those reported in other series. This is a descriptive study over a period from August 2016 to October 2021, during a 5 year-and-2-month period. Immunophenotyping was performed at the flow cytometry unit on a Beckman-Coulter with 6 colors and 2 lasers in the hematology laboratory of the same hospital and data was collected retrospectively from the patients' files, their medical prescription files, kalisil software, and a data collection form we have established. The 440 patients had ages ranging from 1 month to 76 years, with a median of 9.5 years and the overall male-to-female ratio was 1.44. The immunological subtyping revealed that 82.5% of cases were B-ALL and 17.5% were T-ALL; of these B-ALL cases 230 (63.36%) were children (range: 0.1 - 15 years) and 134 (36.91%) were adults (range: 16 - 76 years); T-ALL were distributed in both age groups, 49 cases (37.7%) were children (range: 2 - 15 years) and 28 (21.56%) were adults (range: 18 - 63 years). All patients presented at least one abnormal blood count; thrombocytopenia has been observed in 89.4% of cases, anemia in 86.5% of cases, hyperleukocytosis in 79.8% of cases, leukopenia in 10.6% of cases, and pancytopenia in 4.8% of cases. The frequency of B-cell markers in B-ALL was found to be 363 (100%) for CD19, 323 (88.94%) for CD10, 290 (80%) for CD79a, and 73 (20%) for CD20. CD34 expression was found in 73 (20%) cases of B-ALL. HLA-DR was found in 54 (15%) cases, while TdT was found in 43 (13%) cases. Aberrant expression of myeloid antigens was found in 94 (26%) cases of B-ALL. Among T-ALL, the positivity of CD3 and CD7 was 100% (77 cases), while CD5 was positive in 58 (75%) cases. CD34 expression was found in only 19 cases of T-ALL. CD4 and CD8 expression was checked in only 9 adult patients and 4 pediatric cases. Out of them, 77.82% of cases were negative for both CD4 and CD8. CD4 and CD8 double positivity was seen in only 11.1% of cases, and 22.4% of cases showed either CD4 or CD8 positivity. We concluded that our study was similar to reports in the Americas and Europe, and it was the first large one that describes the immunophenotypic profile of ALL in the Moroccan population.

Selected Articles from This Issue

Davis and colleagues report the first systematic assessment of the safety and pharmacokinetics of dual immune checkpoint inhibition with ipilimumab and nivolumab in pediatric, adolescent, and young adult patients with relapsed or refractory sarcoma. They establish a recommended phase II dose of nivolumab (3 mg/kg) plus ipilimumab (1 mg/kg) and found the combination to be generally well tolerated. In expanded phase II cohorts, the authors observed two sustained partial responses. They further demonstrate that increased ipilimumab dosing (3 mg/kg) in combination with nivolumab (1 mg/kg) carries higher toxicity without clinical benefit in this population.Advanced stage head and neck squamous cell carcinoma (HNSCC) patients are at a high risk of recurrent disease. Due to dismal 5-year survival rates, such patients are in dire need of effective adjuvant therapy. Everolimus, an mTOR inhibitor, has documented activity in HNSCC and is well tolerated with minimal long-term toxicity. In this placebo-controlled phase II trial, Nathan and colleagues are the first to show promising results using everolimus as adjuvant therapy after complete response to definitive treatment in a subset of HPV-negative patients with advanced stage disease. In particular, HPV-negative TP53 mutated tumors appear to yield the best benefit. Thus, subsequent trials using everolimus in this patient population are warranted.TLR9 agonists demonstrated efficacy in activation of the innate and adaptive immune system in preclinical models. Babiker and colleagues investigated the activity of tilsotolimod, an investigational synthetic TLR9 agonist, in patients with refractory solid tumors after progression on standard of care therapies. This early phase clinical trial established safety, maximum tolerated dose, and demonstrated early signs of efficacy of tilsotolimod. In addition, translational data revealed activation of the innate and adaptive immune system through the type I interferon (IFN) pathway, IFNγ and IFNα gene upregulation, increase in inflammatory chemokines, activation of myeloid dendritic cells and antigen presentation, and an increase in genes for checkpoint and costimulatory proteins. The translational results suggest further investigation of tilsotolimod in combination with checkpoint inhibitors in solid tumors.Biomarkers are urgently needed to select chemotherapy regimens in pancreatic ductal adenocarcinoma (PDAC). In this study, Perera and colleagues investigated whether mRNA expression levels of hENT1 predict responsiveness to gemcitabinenab-paclitaxel (GnP) in patients with advanced PDAC. The results of this prospective observational clinical trial using tumor-enriched RNA sequencing revealed higher response rates and improved survival in patients receiving GnP, when tumors were considered hENT1high compared to those that were hENT1low. No difference in response or survival were seen in patients receiving modified FOLFIRINOX. An interaction analysis confirmed hENT1 as a predictive biomarker for GnP response. This suggests that hENT1 expression can be used to identify patients who will respond to GnP.