Tγδ LGLL identifies a subset with more symptomatic disease: analysis of an international cohort of 137 patients.

Tγδ large granular lymphocyte leukemia (LGLL) is a rare variant of T-cell LGLL (T-LGLL) that has been less investigated as compared with the more frequent Tαß LGLL, particularly in terms of frequency of STAT3 and STAT5b mutations. In this study, we characterized the clinical and biological features of 137 patients affected by Tγδ LGLL; data were retrospectively collected from 1997 to 2020 at 8 referral centers. Neutropenia and anemia were the most relevant clinical features, being present in 54.2% and 49.6% of cases, respectively, including severe neutropenia and anemia in ∼20% of cases each. Among the various treatments, cyclosporine A was shown to provide the best response rates. DNA samples of 97 and 94 cases were available for STAT3 and STAT5b mutation analysis, with 38.1% and 4.2% of cases being mutated, respectively. Clinical and biological features of our series of Tγδ cases were also compared with a recently published Tαß cohort including 129 cases. Though no differences in STAT3 and STAT5b mutational frequency were found, Tγδ cases more frequently presented with neutropenia (P = .0161), anemia (P < .0001), severe anemia (P = .0065), and thrombocytopenia (P = .0187). Moreover, Vδ2- cases displayed higher frequency of symptomatic disease. Overall, Tγδ cases displayed reduced survival with respect to Tαß cases (P = .0017). Although there was no difference in STAT3 mutation frequency, our results showed that Tγδ LGLL represents a subset of T-LGLL characterized by more frequent symptoms and reduced survival as compared with Tαß LGLL.

Genetic alterations and MRD refine risk assessment for KMT2A-rearranged B-cell precursor ALL in adults: a GRAALL study.

KMT2A-rearranged (KMT2A-r) B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is widely recognized as a high-risk leukemia in both children and adults. However, there is a paucity of data on adults treated in recent protocols, and the optimal treatment strategy for these patients is still a matter of debate. In this study, we set out to refine the prognosis of adult KMT2A-r BCP-ALL treated with modern chemotherapy regimen and investigate the prognostic impact of comutations and minimal residual disease (MRD). Of 1091 adult patients with Philadelphia-negative BCP-ALL enrolled in 3 consecutive trials from the Group for Research on Adult Acute Lymphoblastic Leukemia (GRAALL), 141 (12.9%) had KMT2A-r, with 5-year cumulative incidence of relapse (CIR) and overall survival (OS) rates of 40.7% and 53.3%, respectively. Molecular profiling highlighted a low mutational burden in this subtype, reminiscent of infant BCP-ALL. However, the presence of TP53 and/or IKZF1 alterations defined a subset of patients with significantly poorer CIR (69.3% vs 36.2%; P = .001) and OS (28.1% vs 60.7%; P = .006) rates. Next, we analyzed the prognostic implication of MRD measured after induction and first consolidation, using both immunoglobulin (IG) or T-cell receptor (TR) gene rearrangements and KMT2A genomic fusion as markers. In approximately one-third of patients, IG/TR rearrangements were absent or displayed clonal evolution during the disease course, compromising MRD monitoring. In contrast, KMT2A-based MRD was highly reliable and strongly associated with outcome, with early good responders having an excellent outcome (3-year CIR, 7.1%; OS, 92.9%). Altogether, our study reveals striking heterogeneity in outcomes within adults with KMT2A-r BCP-ALL and provides new biomarkers to guide risk-based therapeutic stratification.

Efficacy of ruxolitinib in the treatment of relapsed/refractory large granular lymphocytic leukaemia.

Large granular lymphocytic (LGL) leukaemia is a rare chronic lymphoproliferative disorder characterized by an expansion of cytotoxic T or NK cells. Despite a usually indolent evolution, most patients will require a treatment over the course of the disease because of cytopenia or symptomatic associated autoimmune disorders. First-line treatment is based on immunosuppressive agents, namely cyclophosphamide, methotrexate and ciclosporin. However, relapses are frequent, and there is no consensus on the management of relapsed/refractory patients. The implication of the JAK/STAT pathway in the pathogenesis of this disease has prompted our group to propose treatment with ruxolitinib. A series of 21 patients who received this regimen is reported here. Ten patients (47.6%) were refractory to the three main immunosuppressive drugs at the time of ruxolitinib initiation. Ruxolitinib yielded an overall response rate of 86% (n = 18/21), including 3 complete responses and 15 partial responses. With a median follow-up of 9 months, the median response duration was 4 months. One-year event-free survival and 1-year overall survival were 57% and 83% respectively. Mild side effects were observed. Biological parameters, notably neutropenia and anaemia, improved significantly, and complete molecular responses were evidenced. This study supports ruxolitinib as a valid option for the treatment of relapsed/refractory LGL leukaemia.

CALR-mutated patients with low allele burden represent a specific subtype of essential thrombocythemia: A study on behalf of FIM and GBMHM.

A low allele burden (i.e., <20%) of the CALR driver mutation is found in 10.8% of CALR-mutated MPNs, mostly in essential thrombocythemia, and correlates with a milder phenotype and a more indolent evolution compared to patients with an allele burden ≥20%.

Clinical and histological features of histiocytoid Sweet syndrome associated with VEXAS syndrome.

BACKGROUND: VEXAS (Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is caused by acquired somatic mutations in UBA1. Sweet-syndrome-like skin disorders [and especially histiocytoid Sweet syndrome (HSS)] may be associated with VEXAS syndrome. OBJECTIVES: To characterize the clinical and histopathological features of HSS in patients with VEXAS syndrome. METHODS: Skin biopsies with a histological diagnosis of HSS at Rennes University Medical Center (Rennes, France) between October 2011 and January 2022 were reviewed in this study. Sanger sequencing and digital polymerase chain reaction were used to screen skin, blood and bone marrow samples for UBA1 variants, and thus classify patients as having VEXAS syndrome or not. We evaluated the clinical, histological and molecular (UBA1) characteristics of patients with or without VEXAS syndrome. RESULTS: We compared 15 skin biopsies from 7 patients found to have VEXAS syndrome and 19 skin biopsies from 15 patients without VEXAS syndrome. Persistent C-reactive protein elevation, macrocytosis, anaemia and haematological malignancies were more prevalent in patients with VEXAS syndrome [6/7 (86%), 6/7 (86%), 7/7 (100%) and 6/7 (86%), respectively] than in patients without [5/14 (36%), 6/15 (40%), 8/15 (53%) and 8/15 (53%), respectively]. These features sometimes appeared after the first skin manifestations, and a UBA1 mutation was found in the skin of five patients with VEXAS syndrome. Dermal infiltration by reniform histiocytoid cells (myeloperoxidase-positive and/or CD163-positive) and a periadnexal distribution were more frequently observed in VEXAS syndrome biopsies [15/15 (100%) and 3/15 (20%), respectively, vs. 11/19 (58%) and 0/19 (0%) in non-VEXAS syndrome biopsies, respectively]. CONCLUSIONS: Our findings might help pathologists to consider a diagnosis of VEXAS syndrome and to initiate early genetic testing.

Linking the KIR phenotype with STAT3 and TET2 mutations to identify chronic lymphoproliferative disorders of NK cells.

Distinguishing chronic lymphoproliferative disorders of NK cells (CLPD-NK) from reactive NK-cell expansion is challenging. We assessed the value of killer immunoglobulin-like receptor(KIR) phenotyping and targeted high-throughput sequencing in a cohort of 114 consecutive patients with NK cell proliferation, retrospectively assigned to a CLPD-NK group (n = 46) and a reactive NK group (n = 68). We then developed an NK-cell clonality score combining flow cytometry and molecular profiling with a positive predictive value of 93%. STAT3 and TET2 mutations were respectively identified in 27% and 34% of the patients with CLPD-NK, constituting a new diagnostic hallmark for this disease. TET2-mutated CLPD-NK preferentially exhibited a CD16low phenotype, more frequently displayed a lower platelet count, and was associated with other hematologic malignancies such as myelodysplasia. To explore the mutational clonal hierarchy of CLPD-NK, we performed whole-exome sequencing of sorted, myeloid, T, and NK cells and found that TET2 mutations were shared by myeloid and NK cells in 3 of 4 cases. Thus, we hypothesized that TET2 alterations occur in early hematopoietic progenitors which could explain a potential link between CLPD-NK and myeloid malignancies. Finally, we analyzed the transcriptome by RNA sequencing of 7 CLPD-NK and evidenced 2 groups of patients. The first group displayed STAT3 mutations or SOCS3 methylation and overexpressed STAT3 target genes. The second group, including 2 TET2-mutated cases, significantly underexpressed genes known to be downregulated in angioimmunoblastic T-cell lymphoma. Our results provide new insights into the pathogenesis of NK-cell proliferative disorders and, potentially, new therapeutic opportunities.

Five new F10 variants in hereditary factor x deficiency detected by high-throughput sequencing.

INTRODUCTION: Factor X deficiency is a rare inherited bleeding disorder. To date, 181 variants are reported in the recently updated F10-gene variant database. AIM: This study aimed to describe new F10 variants. METHOD: The F10 gene was analysed in 16 consecutive families with FX deficiency by a targeted high-throughput sequencing approach, including F10, F9, F8 genes, and 78 genes dedicated to haematological malignancies. RESULTS: We identified 19 variants (17 missense, one nonsense and one frameshift) and two copy number variations. Two patients presenting a combined FVII-FX deficiency showed a loss of one F10 gene copy (del13q34) associated with a missense variant on the remaining allele, leading to a FX:C significantly lower than the FVII:C level and explaining their unusual bleeding history. We reported five novel variants. Three missense variants (p.Glu22Val affecting the signal peptide cleavage site, p.Cys342Tyr removing the disulphide bond between the FX heavy and light chains, and p.Val385Met located in FX peptidase S1 domain) were detected at compound heterozygosis status in three patients with severe bleeding symptoms and FX:C level below 10 IU/dL. Two truncating variants p.Tyr279* and p.Thr434Aspfs*13 leading to an altered FX protein were found at heterozygous state in two patients with mild bleeding history. CONCLUSION: This study showed the feasibility and the interest of high-throughput sequencing approach for rare bleeding disorders, enabling the report of F10 gene screening in a 3-weeks delay, suitable for clinical use. The description of five new variants may contribute to a better understanding of the phenotype-genotype correlation in FX deficiency.

High tumor burden before blinatumomab has a negative impact on the outcome of adult patients with B-cell precursor acute lymphoblastic leukemia. A real-world study by the GRAALL.

Blinatumomab is a bispecific T-cell engager approved for B-cell precursor acute lymphoblastic leukemia (B-ALL) with persistent minimal residual disease (MRD) or in relapse. The prognostic impact of tumor load has been suggested before other immunotherapies but remains poorly explored before blinatumomab. We retrospectively analyzed the outcome of 73 patients who received blinatumomab either in first complete remission (CR) with MRD (n=35) or at relapse (n=38). Among MRD patients, 91% had MRD >0.01% before blinatumomab, and 89% achieved complete MRD response after blinatumomab. High pre-blinatumomab MRD levels were associated with shorter relapse-free survival (P=0.049) and overall survival (OS) (P=0.011). At 3 years, OS was 33%, 58% and 86% for pre-blinatumomab MRD >1%, between MRD 0.1- 1% and <0.1% respectively. Among relapsed patients, 23 received blinatumomab with overt relapse and 15 were in complete response (CR) after bridging chemotherapy. At 3 years, overall CR rate was 68% and complete MRD response rate was 84%. Patients who directly received blinatumomab had shorter relapse-free survival (P=0.033) and OS (P=0.003) than patients bridged to blinatumomab. Three-year OS was 66% in the latter group compared to 16% in the former group. Our observations suggest that pre-blinatumomab tumor burden should help to design more tailored strategies including tumor load reduction in relapsed patients.

Redefining Therapeutic Drug Monitoring of Tacrolimus in Patients Undergoing Liver Transplantation: A Target Trough Concentration of 4-7 ng/mL During the First Month After Liver Transplantation is Safe and Improves Graft and Renal Function.

BACKGROUND: Currently, the recommended tacrolimus (TAC) trough level (Cmin) after liver transplantation (LT) is 6-10 ng/mL (when associated in triple immunosuppressive therapy). However, few studies have achieved the lower limit of this range, especially below 7 ng/mL. This study evaluated the efficacy of a target TAC Cmin of 4-7 ng/mL after LT. METHODS: Of 1677 LTs performed between 2002 and 2017, 904 LT cases were analyzed. The cases were categorized into the following 3 groups and compared: low- (n = 247, 27.3%), intermediate- (n = 344, 37.9%), and high-exposure groups (n = 313, 34.5%) with TAC Cmin of 4-7 ng/mL, 7-10 ng/mL, and >10 ng/mL, respectively. In addition, propensity score matching was performed to reduce heterogeneity and population bias. RESULTS: At months 1 and 3, when compared with the 2 other groups, the low-exposure group had similar grafts (P = 0.75) and patient (P = 0.77) survival, but lower alanine aminotransferase (P < 0.001), bilirubin (P < 0.001), international normalized ratio (P = 0.046), and creatinine (P < 0.001) levels. After propensity score matching, the bilirubin (P < 0.001) and creatinine (P = 0.001) levels in the low-exposure group still improved at months 3, but the graft (P = 0.86) and patient (P = 0.99) survival were still similar. CONCLUSIONS: A TAC Cmin of 4-7 ng/mL seems safe and capable of improving graft and kidney function. This finding should be confirmed in a prospective randomized trial.

Tailored Digital PCR Follow-Up of Rare Fusion Transcripts after Initial Detection through RNA Sequencing in Hematological Malignancies.

Minimal residual disease (MRD) monitoring plays a pivotal role in the management of hematologic malignancies. Well-established molecular targets, such as PML::RARA, CBFB::MYH11, or RUNX1::RUNX1T1, are conventionally tracked by quantitative RT-PCR. Recently, a broader landscape of fusion transcripts has been unveiled through transcriptomic analysis. These newly discovered fusion transcripts may emerge as novel molecular markers for MRD quantification. In this study, we compared a targeted RNA-sequencing (RNA-seq) approach (FusionPlex) with a whole-transcriptomic strategy (Advanta RNA-Seq XT) for fusion detection in a training set of 21 samples. We evidenced a concordance of 100% for the detection of known fusions, and showed a good correlation for gene expression quantification between the two techniques (Spearman r = 0.77). Additionally, we prospectively evaluated the identification of fusions by targeted RNA-seq in a real-life series of 126 patients with hematological malignancy. At least one fusion transcript was detected for 60 patients (48%). We designed tailored digital PCR assays for 11 rare fusions, and validated this technique for MRD quantification with a limit of detection of <0.01%. The combination of RNA-seq and tailored digital PCR may become a new standard for MRD evaluation in patients lacking conventional molecular targets.

Vacuoles, E1 enzyme, X-linked, autoinflammatory, and somatic syndrome in the intensive care unit: a case report.

BACKGROUND: Vacuoles, E1 enzyme, X-linked, autoinflammatory, and somatic syndrome is a newly discovered inflammatory disease affecting male subjects, for which few data exist in the literature. Here, we describe the case of a patient with known Sweet's syndrome admitted to the intensive care unit and for whom a vacuoles, E1 enzyme, X-linked, autoinflammatory, and somatic syndrome was diagnosed, allowing for appropriate treatment and the patient's discharge and recovery. CASE PRESENTATION: A 70-year-old male White patient was hospitalized in the intensive care unit following an intrahospital cardiac arrest. History started a year before with repeated deep vein thrombosis and episodes of skin eruption compatible with Sweet's syndrome. After a course of oral steroids, fever and inflammatory syndrome relapsed with onset of polychondritis, episcleritis along with neurological symptoms and pulmonary infiltrates. Intrahospital hypoxic cardiac arrest happened during patient's new investigations, and he was admitted in a critical state. During the intensive care unit stay, he presented with livedoid skin lesions on both feet. Vasculitis was not proven; however, cryoglobulinemia screening came back positive. Onset of pancytopenia was explored with a myelogram aspirate. It showed signs of dysmyelopoiesis and vacuoles in erythroid and myeloid precursors. Of note, new deep vein thrombosis developed, despite being treated with heparin leading to the diagnosis of heparin-induced thrombocytopenia. The course of symptoms were overlapping multiple entities, and so a multidisciplinary team discussion was implemented. Screening for UBA1-mutation in the blood came back positive, confirming the vacuoles, E1 enzyme, X-linked, autoinflammatory, and somatic syndrome. Corticosteroids and anti-IL1 infusion were started with satisfactory results supporting patient's discharge from intensive care unit to the internal medicine ward. CONCLUSIONS: Vacuoles, E1 enzyme, X-linked, autoinflammatory, and somatic syndrome should be suspected in male patients presenting with inflammatory symptoms, such as fever, skin eruption, chondritis, venous thromboembolism, and vacuoles in bone marrow precursors. Patients with undiagnosed vacuoles, E1 enzyme, X-linked, autoinflammatory, and somatic syndrome may present with organ failure requiring hospitalization in intensive care unit, where screening for UBA1 mutation should be performed when medical history is evocative. Multidisciplinary team involvement is highly recommended for patient management, notably to start appropriate immunosuppressive treatments.

Adult Low-Hypodiploid Acute Lymphoblastic Leukemia Emerges from Preleukemic TP53-Mutant Clonal Hematopoiesis.

Low hypodiploidy defines a rare subtype of B-cell acute lymphoblastic leukemia (B-ALL) with a dismal outcome. To investigate the genomic basis of low-hypodiploid ALL (LH-ALL) in adults, we analyzed copy-number aberrations, loss of heterozygosity, mutations, and cytogenetics data in a prospective cohort of Philadelphia (Ph)-negative B-ALL patients (n = 591, ages 18-84 years), allowing us to identify 80 LH-ALL cases (14%). Genomic analysis was critical for evidencing low hypodiploidy in many cases missed by cytogenetics. The proportion of LH-ALL within Ph-negative B-ALL dramatically increased with age, from 3% in the youngest patients (under 40 years old) to 32% in the oldest (over 55 years old). Somatic TP53 biallelic inactivation was the hallmark of adult LH-ALL, present in virtually all cases (98%). Strikingly, we detected TP53 mutations in posttreatment remission samples in 34% of patients. Single-cell proteogenomics of diagnosis and remission bone marrow samples evidenced a preleukemic, multilineage, TP53-mutant clone, reminiscent of age-related clonal hematopoiesis. SIGNIFICANCE: We show that low-hypodiploid ALL is a frequent entity within B-ALL in older adults, relying on somatic TP53 biallelic alteration. Our study unveils a link between aging and low-hypodiploid ALL, with TP53-mutant clonal hematopoiesis representing a preleukemic reservoir that can give rise to aneuploidy and B-ALL. See related commentary by Saiki and Ogawa, p. 102. This article is highlighted in the In This Issue feature, p. 101.

Toward a Better Classification System for NK-LGL Disorders.

Large granular lymphocytic leukemia is a rare lymphoproliferative disorder characterized by a clonal expansion of T-lineage lymphocyte or natural killer (NK) cells in 85 and 15% of cases respectively. T and NK large granular leukemia share common pathophysiology, clinical and biological presentation. The disease is characterized by cytopenia and a frequent association with autoimmune manifestations. Despite an indolent course allowing a watch and wait attitude in the majority of patients at diagnosis, two third of the patient will eventually need a treatment during the course of the disease. Unlike T lymphocyte, NK cells do not express T cell receptor making the proof of clonality difficult. Indeed, the distinction between clonal and reactive NK-cell expansion observed in several situations such as autoimmune diseases and viral infections is challenging. Advances in our understanding of the pathogenesis with the recent identification of recurrent mutations provide new tools to prove the clonality. In this review, we will discuss the pathophysiology of NK large granular leukemia, the recent advances in the diagnosis and therapeutic strategies.