NK-cell Lymphoproliferative Disorders Research Articles

Clinical features and prognosis of chronic natural killer cell lymphoproliferative disorders

ABSTRACT Objective To analyze the current treatment status and prognostic regression of the chronic NK cell lymphoproliferative disorder (CLPD-NK). Methods We retrospectively analyzed the clinical features, treatment and prognosis of 18 patients with CLPD-NK who were treated at our Hospital between September 2016 and September 2022. Results Eighteen patients were included: three patients were treated with chemotherapy, five patients underwent immune-related therapy, one patient was treated with glucocorticoids alone, five patients were administered granulocyte colony-stimulating factor, blood transfusion therapy, or anti-infection therapy, followed by observation and follow-up, and four patients were observed without treatment. Fifteen patients survived, including two patients who achieved complete remission (CR) and seven patients who achieved partial remission (PR), of whom one patient progressed to Aggressive NK-cell leukemia (ANKL) and sustained remission after multiple lines of treatment; three patients were not reviewed, of which one patient was still in active disease, three patients developed hemophagocytic syndrome during treatment and eventually died, one of them had positive Epstein–Barr virus (EBV) expression. The 5-years overall survival rate was 83%. Conclusion Most patients with CLPD-NK have inert progression and a good prognosis, whereas some patients have a poor prognosis after progressing to ANKL and combined with hemophagocytic syndrome. Abnormal NK cells invading the center suggest a high possibility of ANKL development, and immunosuppressants and hormones are effective treatments for this disease.

What is new in the classification of peripheral Tcell lymphomas?

In this review focus article, we highlight the main modifications introduced in the latest 2022 International Consensus Classification and World Health Organization classification (ICC and WHO-HAEM5) of matureT (and NK) cell neoplasms (PTCLs) and consequent implications for diagnostic practice. The changes result from recent advances in the genomic and molecular characterization of PTCLs and enhanced understanding of their pathobiology. Specifically, consideration is given to the following groups of diseases: Epstein-Barr virus (EBV)-associated neoplasms; follicular helper Tcell lymphoma; anaplastic large cell lymphomas; primary intestinalT and NK cell lymphomas and lymphoproliferative disorders; and PTCL, not otherwise specified.

T-Cell Lgll of the Γδ Subtype: Clinically Relevant Fact or Academically Interesting Finding?

Large granular lymphocyte leukemia (LGLL) is a rare group of mature T and NK cell lymphoproliferative disorders, with an annual incidence of 0.2 - 0.72 cases per 1 million individuals. Median age of onset is 65, with case prevalence roughly equivalent between sexes. T-Cell LGLL (T-LGLL) makes up 85-91% of cases. The majority of T-LGLL clones express Tαβ, with only 5% of cases expressing Tγδ. Outcomes and treatment data on this subtype is limited. Recent observational data suggest reduced overall survival (OS), increased incidence of cytopenias and associated autoimmune diseases, and favorable response to first line therapy with cyclosporine, in comparison to the Tαβ subtype. Here, we summarize disease biology and clinical presentation and provide review of recent literature describing clinical course and treatment options in the context of a patient case. A woman in her early 70's with osteoporosis, asthma and hypertension presented to hematology after she was found to have leukocytosis of 12.1* 103/µL during routine lab work. CBC w/differential showed lymphocytosis of 11.0* 103/µL with absolute neutrophil count of 496 *103/µL and thrombocytopenia (121* 103/µL). She was asymptomatic without history of malignancy or autoimmune disease, prior available labwork was normal and physical exam was unremarkable. Peripheral smear showed atypical lymphocytes, with flow cytometry demonstrating 50.45% clonality with CD2+, CD3+, CD4-, CD7+, CD8 +/- , CD16+, CD 56-, CD57+/-, Tγδ + phenotype. Bone marrow biopsy demonstrated hypercellular (70%) marrow with scattered lymphoid aggregates with clonal infiltration of 20% core cellularity by CD3 immunohistochemistry. Bone marrow flow demonstrated the T-Cell phenotype seen in peripheral blood. T-Cell clonality study demonstrated TCR gamma chain rearrangement. PET/CT showed mildly increased FDG uptake throughout bone marrow. Next-Generation Sequencing confirmed mutations of STAT3 (D661Y), ASXL1, and TET2. There is conflicting data on whether Tγδ positivity portends reduced OS compared to Tαβ. Observational studies show that Tγδ is more frequently symptomatic and conveys higher risk of cytopenias. Not all cases require treatment. Treatment is usually prompted by single-lineage cytopenias. First line single agent therapy with methotrexate (MTX), cyclosporine, and cyclophosphamide have shown similar overall response rates of 40-50%, though STAT3 mutated disease is associated with better response to MTX. STAT3 mutations are associated with more severe cytopenias, more frequent autoimmune/inflammatory disorders, and more frequently required therapy, however neither STAT mutations nor cytopenias convey decreased OS in Tγδ disease. STAT3 and STAT5b mutations occur in 40% of all LGLL cases, with STAT3 mutations associated with neutropenia and rheumatoid arthritis. Nearly two thirds of STAT3 genetic mutations are Y640F and D661Y. Our patient was initiated on prednisone, though due to poor tolerance was transitioned to MTX titrated to 12.5 mg weekly. She has remained on this dose with good tolerability for 18 months with resolution of lymphocytosis and improvement in neutropenia. T-LGLL has an OS of 9 years. Rarity of Tγδ disease has limited the ability to generate subtype specific survival data. The largest retrospective study to date included 137 Tγδ patients across 8 centers and provided a signal that Tγδ disease may predict reduced OS compared to the Tαβ subtype, however data was limited by disparate median follow-up time amongst cohorts due to high rates of censorship in the Tγδ cohort. Median OS was not reached at median follow up time of 48 months. This trend would be clinically expected given that Tγδ subtype has been consistently associated with severe cytopenias and autoimmune diseases, but should not be accepted until higher quality evidence is generated over longer median follow-up times. The same study found better responses to cyclosporine as first line therapy, an interesting observation as MTX has been generally accepted as first line therapy based on predominantly retrospective studies, though these studies did not stratify treatment responses by TCR phenotype. These findings underscore the need for prospective studies characterizing Tγδ specific disease course, survival analyses and treatment response.

Ruxolitinib Promotes Clinical Responses in Large Granular Lymphocytic Leukemia Via Suppression of JAK/STAT-Dependent Inflammatory Cascades

Background: Large granular lymphocytic leukemias (LGL) are T or NK-cell lymphoproliferative disorders that are characterized by myelosuppression and frequent mutations in STAT3. Commonly used agents include low doses of methotrexate or cyclophosphamide. Among 5 patients (pts) with LGL treated on our phase II study of ruxolitinib in T-cell lymphoma (Moskowitz, et al. Blood 2021), 2 achieved partial response (PR) and 2 achieved stable disease, suggesting oncogenic dependence on JAK/STAT pathway activity in LGL. Methods: To further explore the efficacy and mechanism of JAK1/2 blockade in LGL, we expanded our phase II study to include 23 pts with relapsed/refractory LGL. This sample size was chosen to allow for narrowing of the 95% confidence interval to 54-87% (Wilson score method) if similar efficacy was observed. Pts received ruxolitinib 20mg PO BID continuously. Responses were assessed after cycles 2, 5, and every 3 cycles thereafter using the response assessment from the ECOG-5998 study for LGL. Furthermore, stable disease (SD) was defined as improvement in cytopenia(s) by 1 grade (without meeting criteria for PR) for a minimum of 6 months. Overall response rate (ORR) included complete response (CR) plus PR; clinical benefit rate (CBR) included ORR plus SD. In parallel, we performed single-cell RNA sequencing (scRNA-seq) on paired C1D1 and C1D8 peripheral blood mononuclear cells (PBMCs) from 7 patients (5 PR, 1 SD, and 1 non-responder) and plasma proteomic profiling on 5 patients (3 PR, 1 SD, and 1 POD). Results: Among 23 pts, median age was 58 (31-86), 13 (57%) were male, 19 (83%) were white, 1 (4%) was black. Median number of prior therapies was 2 (range 0-5). 12/22 (54%) had STAT3 mutations (of whom 1 also had a JAK1 mutation); 1 had a JAK2 mutation, 1 pt was missing sequencing. Baseline cytopenias included anemia (n=14, 61%), thrombocytopenia (n=12, 52%), and/or neutropenia (n=16, 70%). Among 20 pts evaluable for response (3 too early), there were 5 (25%) CRs, 6 (30%) PRs, and 4 (20%) SD. ORR and CBR were 55% and 75% respectively. Median event free survival (EFS) was not reached and was 68% (95% CI: 50-93) at 14 months ( Fig. 1A). STAT3 mutation status predicted for improved EFS (14-month EFS 100% vs 40%, p=0.007). After a median duration of treatment of 13.1 months, there were no unexpected toxicities. Severe adverse events included febrile neutropenia (n=3, 13%) and herpes zoster (n=1, 4%). To understand the mechanism by which ruxolitinib improved hematologic parameters in LGL, we performed unbiased proteomic analysis of peripheral blood plasma samples using the OLink 96 Inflammation and Immune Response Platforms. Ruxolitinib led to a decrease in several soluble mediators known to be driven by interferon-driven JAK/STAT activation, including CXCL9, CXCL10, and PD-L1, as well as TNF ( Fig. 1B). Several of these factors have been shown to suppress hematopoietic stem cell function, suggesting a JAK/STAT-dependent paracrine mechanism by which LGL leads to myelosuppression. ScRNA-seq of PBMCs identified LGL cells based on expression of cytotoxic genes, including NKG7, CST7, CCL5, GZMB and PRF1. Analysis of cell type proportions within the peripheral blood showed that patients achieving a PR to Ruxolitinib showed a decrease in the proportion of circulating myeloid cells. Gene set enrichment analysis (GSEA) of LGL cells revealed substantial downregulation of both JAK/STAT signaling and TNF signaling in LGL cells in PR but not SD patients, whereas persistently elevated TNF signaling was seen not only in LGL cells but also circulating myeloid and naïve T-cells in SD patients, suggesting that LGL cells might promote bone marrow suppression via paracrine effects on the bystander host immune system. Network analysis of LGL cells and non-malignant peripheral blood immune cells is ongoing. Conclusions: Ruxolitinib induced durable responses in pts with LGL and therefore may represent an option for pts requiring treatment. STAT3 mutation status was predictive of EFS and responses were associated with JAK/STAT pathway down-regulation, demonstrating on-target effects. Integrated immune profiling suggests that ruxolitinib may interrupt JAK/STAT-dependent paracrine inflammatory signals that promote bone marrow suppression. An ongoing phase II study of ruxolitinib in LGL will aid in clarifying optimal dosing and confirming both efficacy and mechanism of action (NCT05592015).

A 9-year-old patient with indolent NK cell lymphoproliferative disorder: What role does an inherited SESN3 mutation play?

A 9-year-old patient with indolent NK cell lymphoproliferative disorder: What role does an inherited SESN3 mutation play?

Genomic landscape of T-large granular lymphocyte leukemia and chronic lymphoproliferative disorder of NK cells: a single institution experience

LGLL is a rare and chronic lymphoproliferative disorder including T-LGLL and CLPD-NK. Here, we investigated the genomic profiles of LGLL with a focus on STAT3 and STAT5B mutations in a cohort of 49 patients (41 T-LGLL, 8 CLPD-NK). Our study indicated that STAT3 was identified in 38.8% (19/49) of all patients, while STAT5B occurred in only 8.2% (4/49) of patients. We found that STAT3 mutations were associated with lower ANC in T-LGLL patients. The average number of pathogenic/likely pathogenic mutations in STAT3/STAT5B-mutated patients was significantly higher than that in WT patients (1.78 ± 1.17 vs 0.65 ± 1.36, p = 0.0032). Additionally, TET2-only mutated T-LGLL (n = 5) had a significant reduction in platelet values compared with the WT (n = 16) or STAT3-only mutated T-LGLL (n = 12) (p < 0.05). In conclusion, we compared the somatic mutational landscape between STAT3/STAT5B WT and mutated patients and correlate with their distinct clinical characteristics.

Indolent NK-cell lymphoproliferative disorder of the GI tract: a rare indolent neoplasm of the GI tract

Indolent NK-cell lymphoproliferative disorder of the GI tract: a rare indolent neoplasm of the GI tract

Clinicopathological findings, prognosis, and Epstein–Barr virus infection in rheumatoid arthritis patients with other iatrogenic immunodeficiency-associated T- and NK-cell lymphoproliferative disorders

BackgroundOther iatrogenic immunodeficiency-associated (OIIA) T- and natural killer (NK)-cell lymphoproliferative disorders (TNK-LPDs) are rare in patients with rheumatoid arthritis (RA).MethodsWe investigated the clinicopathological characteristics, Epstein–Barr virus (EBV) infection, genetic findings, therapeutic response, and prognostic factors in 21 RA patients with OIIA TNK-LPDs and compared these with those of 39 with OIIA B-cell LPDs (B-LPDs) and 22 with non-OIIA B-LPDs.ResultsImmunohistologically, 11 patients (52%) showed CD4+ T-LPDs, and 7 had a T follicular helper (TFH) phenotype. The other nine patients (43%) showed CD8+ T-LPDs, and the remaining one (5%) had features of CD3+ CD4− CD8− nasal type TNK-cell lymphoma. CD30+, p53+, and CMYC+ atypical lymphocytes were identified in seven (33%), eight (38%), and five (24%) patients, respectively. In situ hybridisation detected EBV-encoded RNA (EBER) + large atypical lymphocytes in five patients (24%). Nine of 17 patients (53%) showed clonal peaks of TCRγ by polymerase chain reaction. Withdrawal of MTX and biologic drugs was effective in 12 patients (57%), and 8 (38%) received chemotherapies. Two patients with TFH+ or EBV+ CD4+ CD30+ large cell peripheral T-cell lymphoma, one with CD8+ systemic anaplastic large cell lymphoma, and two with systemic EBV+ CD8+ T-cell lymphoma of childhood showed a lethal progressive clinical course within 13 months. Moreover, > 500 U/L LDH, large atypical lymphocytes, expression of CD30, p53, and CMYC, and EBER+ atypical lymphocytes were significantly poor prognostic factors for overall survival (p < 0.05). Median interval from RA onset to OIIA TNK-LPDs was 72 months, which was shorter than 166 months in OIIA B-LPDs (p = 0.003). EBV+ atypical and reactive lymphocytes were frequently found in 15 patients with OIIA TNK-LPDs (71%), in 27 with OIIA B-LPDs (69%), and only in 3 with non-OIIA B-LPDs (14%).ConclusionsOIIA TNK-LPDs occurred in early phase of RA, compared with OIIA B-LPDs, and occasionally showed a lethal progressive clinical course. Detection of OIIA TNK-LPD patients with poor prognostic factors is necessary. EBV infection in immunosuppressed patients due to persistent RA, MTX, and biologic drugs may play a role in forming the tumour microenvironment and lymphomagenesis of TNK-LPDs.

DR-01, a Non-Fucosylated Anti-CD94 Antibody, Depletes Leukemic Cells in Ex Vivo and In Vivo Models of Large Granular Lymphocyte Leukemia

Large granular lymphocyte leukemia (LGLL) is a rare leukemia more frequently occurring in the elderly population with three major subtypes: T-LGLL, chronic lymphoproliferative disorder of NK cells (CLPD-NK) and aggressive NK cell leukemia (ANKL). Over 50% of patients develop complications including severe neutropenia, thrombocytopenia and anemia, thus predisposing patients to opportunistic infections. In addition, treatments are limited to standard immunosuppressive therapy such as methotrexate, cyclosporine or cyclophosphamide, with complete response rates of only 50% or less for each agent. Thus, novel and effective therapies for LGLL patients are critically needed. Dren Bio is developing DR-01, a non-ligand blocking, non-fucosylated monoclonal antibody targeting CD94. CD94 is a type II transmembrane receptor identified on mature, cytotoxic lymphocytes such as healthy NK and terminally differentiated CD8 T cells. In the context of disease, CD94 is known to be upregulated on LGLL cells. DR-01 functions through depletion of target cells via antibody-mediated cellular cytotoxicity (ADCC) by means of fratricide, a method in which the same cell type induces ADCC on each other. Through characterization of DR-01 using various ELISA and cell-based assays, DR-01 was determined to bind with nanomolar affinity to CD16a (EC50: 0.04µg/mL) and to CD94 on healthy human donor NK cells, cynomolgus monkey NK cells and LGLL cells (EC50: 0.5-1nM). DR-01 induces potent, dose-dependent depletion of CD94+ cells in ex vivo ADCC assays (IC50: 1ng/mL) of peripheral blood mononuclear cells (PBMCs) from healthy and diseased individuals. Furthermore, DR-01 has been shown to be well tolerated in a 4-week dose-range finding and Good Laboratory Practice (GLP) study in cynomolgus monkeys from 5-100mg/kg on a weekly dosing regimen. A 12-color flow cytometry panel was applied to a cohort of patient LGLL PBMCs to profile CD94 expression and other cytotoxic markers associated with the disease, including CD16, CD57 and functional binding partners of CD94 such as NKG2A and NKG2C. CD94 was identified on 97% (37/38) of patient samples screened, ranging from 400 to 725,000 receptors per cell. All patient leukemic cells expressed variable levels of CD16 and CD57. NKG2A and NKG2C were present in over 5% of total leukemic cells in 37% (14/38) and 21% (8/38) of patient samples, respectively. In addition, DR-01 was able to deplete LGL leukemic cells with high potency and in a dose-dependent manner in a functional ADCC assay (IC50:1-10ng/mL). The mechanism of fratricide was demonstrated through degranulation of the leukemic population via expression of CD107a. Cytokine profiling results are pending. To demonstrate in vivo efficacy of DR-01 in a disease model of LGLL, humanized NSG-Tg(hIL-15) mice engrafted with patient LGLL splenocytes were utilized. Optimal splenocyte engraftment (5-20% human CD45+ cells in blood) was achieved within 3 weeks post-inoculation with 10 million PBMCs per pre-sublethally irradiated mouse. The engrafted leukemic population partially preserved the CD94 expression profile from the patient leukemic cells and was successfully depleted (>90%) in blood, bone marrow, spleen and liver 1-week post-treatment with a single dose of DR-01 at 5mg/kg. Overall, DR-01 is a non-fucosylated anti-CD94 antibody with high affinity and potent leukemic cell depleting ability ex vivo and in vivo. The favorable toxicity profile of DR-01 in cynomolgus monkeys precede clinical studies in LGLL patients. Additional profiling and evaluation of DR-01 in LGLL patient samples ex vivo as part of a pre-phase I study is ongoing. A phase I/II trial has been initiated to assess the safety and efficacy of DR-01 in previously treated LGLL patients.

Improving Prognosis of Aggressive Natural Killer Cell Leukemia in Japan

Introduction Aggressive natural killer cell leukemia (ANKL) is a rare leukemic form of mature NK cell neoplasm that is closely associated with the Epstein-Barr virus (EBV). Patients with ANKL show a fulminant clinical course and poor prognosis with a median overall survival (OS) of a few months after diagnosis. L-asparaginase (L-asp)-containing chemotherapies and allogeneic hematopoietic stem cell transplantation (HSCT) are considered as effective therapeutic strategies. However, owing to the rarity of this disease, the characteristics and outcomes of ANKL remain unclear. Methods Data of 103 patients diagnosed with ANKL between 2002 and 2021 from 64 hospitals were retrospectively analyzed. Diagnosis was based on the World Health Organization classification and was verified by two co-authors (AF and RS). Patients registered in our previous ANKL studies were excluded. Results Patient's median age was 50 years (range, 17-90 years), and males accounted for 58%. Twelve patients (12%) had a medical history of chronic active EBV infection (9%), severe mosquito bite allergy (5%), and chronic lymphoproliferative disorder of NK cells (1%). B symptoms were commonly observed at the time of diagnosis (89%). Performance status (PS) was poor (2-4) in more than half of patients (53%). The median percentage of ANKL cells was 20.0% (range, 0-93.4) in bone marrow (BM) and 10.3% (range, 0-89) in peripheral blood (PB). ANKL cells express CD2 (95%), CD7 (53%), CD16 (41%), CD56 (95%), and EBER (86%). Fifty-two patients analyzed (58%) had chromosomal abnormalities by G-banding method, including chromosome 17 abnormalities in 19, deletion of 6q in 11, and isochromosome 7 in 5. Blood tests at diagnosis typically showed pancytopenia with a median white blood cell count of 2,900/μl, hemoglobin level of 10.3g/dl, and platelets 4.3×104/μl. High serum lactate dehydrogenase and soluble interleukin-2 receptor level were also observed (median, 882U/l and 8,475U/dl, respectively). The most common extra-nodal site of involvement was the BM (100%), followed by the spleen (84%), liver (70%), and PB (59%). Median OS of the present cohort was 5.3 months, and 1-year OS was 25.7%. Prognosis was significantly better in patients who underwent HSCT than in those who did not undergo HSCT (P < 0.001). The median OS and 1-year OS were 12.0 months and 52.3% in the former group and 1.7 months and 3.8% in the latter. Eighty-three patients received multi-agents-containing chemotherapy, while the others received single agent or did not receive any anti-lymphoma chemotherapy owing to poor general condition. The most common first-line chemotherapy was the SMILE regimen (39%), followed by anthracycline-based regimens, mainly CHOP (24%), DeVIC (15%) and other L-asp-containing regimens (8%). The response rate was highest in patients treated with SMILE (66%), followed by those who received other L-asp-containing regimens (57%), DeVIC (36%) and anthracycline-based regimens (32%). OS was significantly better in patients who received SMILE than in those who did not receive SMILE (1-year OS 39.3% vs. 12.1%, P < 0.001, Figure). Furthermore, the HSCT rate was significantly higher in patients who received SMILE (68% vs. 26%, P < 0.001). Multivariate analysis using the Cox proportional hazards model showed good PS (0-1) (hazard ratio [HR] 0.43, 95% confidence interval [CI] 0.23-0.91, P = 0.03), administration of SMILE (HR 0.43, 95% CI 0.23-0.80, P = 0.009), and HSCT (HR 0.26, 95% CI 0.12-0.58, P = 0.001) were independent factors associated with favorable OS. Conclusion The present study showed better OS as compared with our previous study. The SMILE chemotherapy and HSCT were suggested to be key components of the therapeutic strategy for ANKL. Further studies are warranted to validate these findings. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Cellular Origins and Pathogenesis of Gastrointestinal NK- and T-Cell Lymphoproliferative Disorders.

Simple SummaryIntestinal T- and NK-cell lymphoproliferative disorders are a group of rare gastrointestinal disorders that arise from immune cells in the intestinal mucosa that are also relatively unknown. Diseases such as indolent T-cell lymphoproliferative disorders of the gastrointestinal tract do not even require treatment, whereas others, such as monomorphic epitheliotropic intestinal T-cell lymphoma, will generally cause death within a year. No effective treatment is currently available, as little is known about how these tumours form or even what cells they arise from. This article summarizes the current state of knowledge about the main types of immune cells in the gastrointestinal mucosa and the processes by which they may transform into neoplasms. The clinical behaviour, pathological appearances and the molecular alterations that underlie these diseases are also discussed.The intestinal immune system, which must ensure appropriate immune responses to both pathogens and commensal microflora, comprises innate lymphoid cells and various T-cell subsets, including intra-epithelial lymphocytes (IELs). An example of innate lymphoid cells is natural killer cells, which may be classified into tissue-resident, CD56bright NK-cells that serve a regulatory function and more mature, circulating CD56dim NK-cells with effector cytolytic properties. CD56bright NK-cells in the gastrointestinal tract give rise to indolent NK-cell enteropathy and lymphomatoid gastropathy, as well as the aggressive extranodal NK/T cell lymphoma, the latter following activation by EBV infection and neoplastic transformation. Conventional CD4+ TCRαβ+ and CD8αβ+ TCRαβ+ T-cells are located in the lamina propria and the intraepithelial compartment of intestinal mucosa as type ‘a’ IELs. They are the putative cells of origin for CD4+ and CD8+ indolent T-cell lymphoproliferative disorders of the gastrointestinal tract and intestinal T-cell lymphoma, NOS. In addition to such conventional T-cells, there are non-conventional T-cells in the intra-epithelial compartment that express CD8αα and innate lymphoid cells that lack TCRs. The central feature of type ‘b’ IELs is the expression of CD8αα homodimers, seen in monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), which primarily arises from both CD8αα+ TCRαβ+ and CD8αα+ TCRγδ+ IELs. EATL is the other epitheliotropic T-cell lymphoma in the GI tract, a subset of which arises from the expansion and reprograming of intracytoplasmic CD3+ innate lymphoid cells, driven by IL15 and mutations of the JAK-STAT pathway.

Unrelated cord blood transplantation for adult-onset EBV-associated T-cell and NK-cell lymphoproliferative disorders.

Adult-onset EBV-associated T-cell and NK-cell lymphoproliferative disorders (EBV-T/NK-LPDs) often progress rapidly, and require allogeneic stem cell transplantation early in the course of treatment. Unrelated cord blood transplantation (UCBT) is a readily available option for patients without HLA-matched donors. We retrospectively analyzed the outcomes of 12 UCBT in adult patients with chronic active EBV infection (CAEBV, n = 8), EBV-positive hemophagocytic lymphohistiocytosis following primary EBV infection (n = 2), hydroa vacciniforme-like lymphoproliferative disorder (n = 1), and systemic EBV-positive T-cell lymphoma of childhood (STCLC, n = 1). The median age at transplantation was 31.5years (range 19-58). At the median follow-up time for survivors, which was 6.3years (range 0.3-11.3), 3-year overall survival (OS) rates in all patients and 8 CAEBV patients were 68.2% (95% CI 28.6-88.9) and 83.3% (95% CI 27.3-97.5), respectively. Graft failure occurred in 4 of 8 CAEBV patients, requiring a second UCBT to achieve neutrophil engraftment. The cumulative incidence of grade II-IV acute GVHD was 33.3% (95% CI 9.1-60.4%). The EBV-DNA load became undetectable or very low after UCBT in all cases. UCBT may be a promising treatment option for adult-onset EBV-T/NK-LPDs.

Indolent T- and NK-Cell Lymphoproliferative Disorders of the Gastrointestinal Tract: Current Understanding and Outstanding Questions

Indolent T- and NK-cell lymphoproliferative disorders of the gastrointestinal tract are uncommon clonal neoplasms that have a protracted clinical course and limited response to therapy. In recent years, advances in the immunophenotypic, genetic, and clinical characterization of these disorders have led to increased awareness and a better understanding of disease pathogenesis. However, many questions remain unanswered, including those concerning the cell(s) of origin, inciting immune or environmental factors, and the molecular pathways underlying disease progression and transformation. In this review, we discuss recent findings regarding the immunophenotypic and genomic spectrum of these lymphoproliferative disorders and highlight unresolved issues.

Varying Presentations of EBV-associated Clinical Entities with Emphasis on EBV-Associated T- and NK-cell Lymphoproliferative Disorders of Childhood

The Epstein-Barr Virus-associated T- and NK-cell lymphoproliferative disorders are a group of hematologic disturbances that occur in pediatric age groups. The literature describes extensive heterogeneity in the presentation of this disease, with a noncanonical reaction to Epstein-Barr virus infection underpinning the wide variety of clinical manifestations. In this review, we discuss chronic active Epstein-Barr virus infection, hypersensitivity to mosquito bites, Alice in Wonderland syndrome, Hydroa vacciniforme-like lymphoproliferative disorder, and the clinical and histologic findings of Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis and systemic Epstein-Barr-positive T-cell lymphoproliferative disorder of childhood.

Clinical Features and Treatment Outcomes of Large Granular Lymphocytic Leukemia Coexisting with Autoimmune Diseases

Introduction:Large granular lymphocytic leukemia (LGLL) is a rare, indolent malignancy arising from cytotoxic T cells (T-LGLL, ~85%) or NK cells [chronic NK-cell lymphoproliferative disorder (CLPD-NK), ~15%]. When treatment is needed, single-agent immunosuppressive therapeutics are usually used, including low-doses of methotrexate (MTX), cyclophosphamide (Cy), and cyclosporine A (CSA). The coexistence of LGLL with autoimmune diseases (ADs) especially rheumatoid arthritis (RA) and Felty Syndrome (FS) has been reported in some patients (pts), suggesting a role of initial strong antigenic stimuli from autoantigens in the pathogenesis of LGLL. However, it remains unclear whether AD-associated LGLLs have unique clinical features or treatment outcomes. We have recently published the largest retrospective study of 319 LGLL cases (Dong et al. 2021). Here we report the outcomes of the LGLL pts with coexisting ADs.Methods:All patients who presented to Moffitt Cancer Center from 2001 to 2020 with a diagnosis of coexistence of T-LGLL or CLPD-NK and AD were included. Diagnostic criteria, treatment and response evaluation were reported elsewhere (Dong et al. 2021). Comparison of response rates was performed using Fisher's exact test or Chi-square test when appropriate. Median survival was estimated using Kaplan-Meier method and compared with log-rank test. Multivariate analysis was not done due to limitation of sample size. All analyses were done using SAS 9.4.Results:The patient characteristics are listed in Table 1. Among the 83 pts, 77 (92.8%) had T-LGLL and 6 (7.2%) had CLPD-NK. The most common ADs were RA [38 (45.8%)], followed by FS 13 (15.7%), and inflammatory bowel disease, polymyalgia rheumatica and vasculitis [5 (6%) each]. 33 (39.8%) pts needed treatment for LGLL. Three of the 5 pts who underwent NGS testing were positive for STAT3 mutation.In our practice, we favor MTX as the frontline therapy for LGLL with coexisting ADs such as RA. The treatments and responses are presented in Table 2. Among the 29 pts who received MTX, 24 (82.8%) had response, including 6 (20.7%) complete response (CR). Among the 11 pts treated with Cy, 9 (81.8%) had response and 5 (45.5%) had CR. CSA was used in 6 pts and had response in 3 (50.0%) and CR in 2 (33.3%). The response rates were not different between MTX, Cy and CSA, neither were the CR rates, although the statistical testing was limited by sample size. Consistent with our previous findings in LGLL, the response to growth factor (GCSF) was low and only 1 of 4 pts responded. Compared to the 131 LGLL pts without co-existing AD in our series, AD-associated LGLL had higher response rates to MTX, Cy or CSA (61.9% vs 78.3%, respectively, p=0.04).Interestingly, pts with CLPD-NK were less likely to respond to CSA, MTX or Cy compared to pts with T-LGLL [1/5 (20%) vs 35/41 (85.4%), p=0.006]. The type of AD, age, splenomegaly, anemia, neutropenia, thrombocytopenia or STAT3 mutation were not associated with response.With a median follow-up of 5.2 (IQR 2.0-9.5) years, the median survival was 10.9 (95% CI 8.1-not estimable) years. Anemia and thrombocytopenia were associated with worse survival (figures 1 and 2). The median survival for pts with vs without anemia was 8.1 (95% CI 3.9-not estimable) years vs not estimable (95% CI 8.7-not estimable), p=0.01. The median survival for pts with vs without thrombocytopenia was 8.4 (95% CI 3.8-10.1) years vs 13.3 (95% CI 8.1-not estimable) years, p=0.05. The type of LGLL, blood LGL count, splenomegaly, or neutropenia were not associated with survival.Conclusions:The majority (~80 %) of LGLL pts with AD responded to MTX, Cy or CSA, although CR rate was low (20-45%). Interestingly, CLPD-NK pts were less likely to respond compared to T-LGLL which could be attributed to a small sample size and warrants an expanded case study. Anemia and thrombocytopenia were associated with worse survival. Future studies will be of interest to evaluate the hematological responses of LGLL in patients with coexisting ADs treated with FDA-approved biological agents for AD such as TNF inhibitors, IL-6 antagonists and T-Cell co-stimulation blocker. Such studies may provide insights into LGLL treatment as both diseases may share some common pathogenic pathways. [Display omitted] DisclosuresSokol: Kyowa-Kirin: Membership on an entity's Board of Directors or advisory committees; Dren Bio: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure:Rituximab and alemtuzumab have not been approved by FDA for LGL leukemia.

Large granular lymphocytic leukemia - A retrospective study of 319 cases.

Large granular lymphocytic leukemia (LGLL) is a rare hematological malignancy that arises from cytotoxic T lymphocytes (T-LGLL) in 85% of cases and natural killer (NK) cells in the rest. A significant knowledge gap exists regarding the pathogenesis, treatment choices, and prognostic factors of LGLL. We report a cohort of 319 consecutive LGLL patients who presented to our cancer center between 2001 and 2020. A total of 295 patients with T-LGLL and 24 with chronic NK-cell lymphoproliferative disorder (CLPD-NK) were identified. The median age was 65 years (range, 17-90 years). Eighty-three patients (26.0%) had autoimmune diseases. A total of 119 patients (37.3%) had coexisting malignancies, 66 (20.7%) had solid tumors, and 59 (18.5%) had hematological malignancies. Most coexisting malignancies were diagnosed before the diagnosis of LGLL. Treatment was needed for 57% of patients. Methotrexate (MTX), cyclophosphamide (Cy), and cyclosporine A (CSA) were most used and had similar response rates between 61.5%-74.4%. Cy produced more complete responses (32.3%) compared to MTX and CSA (15.7% and 23.1%, respectively). Thrombocytopenia, splenomegaly, and female gender (after controlling for autoimmune diseases) were associated with decreased response rates to MTX, CSA, or Cy. Autoimmune diseases were associated with increased response rates. Thrombocytopenia was an independent risk factor for worse survival.

Frequent somatic TET2 mutations in chronic NK-LGL leukemia with distinct patterns of cytopenias

AbstractChronic natural killer large granular lymphocyte (NK-LGL) leukemia, also referred to as chronic lymphoproliferative disorder of NK cells, is a rare disorder defined by prolonged expansion of clonal NK cells. Similar prevalence of STAT3 mutations in chronic T-LGL and NK-LGL leukemia is suggestive of common pathogenesis. We undertook whole-genome sequencing to identify mutations unique to NK-LGL leukemia. The results were analyzed to develop a resequencing panel that was applied to 58 patients. Phosphatidylinositol 3-kinase pathway gene mutations (PIK3CD/PIK3AP1) and TNFAIP3 mutations were seen in 5% and 10% of patients, respectively. TET2 was exceptional in that mutations were present in 16 (28%) of 58 patient samples, with evidence that TET2 mutations can be dominant and exclusive to the NK compartment. Reduced-representation bisulfite sequencing revealed that methylation patterns were significantly altered in TET2 mutant samples. The promoter of TET2 and that of PTPRD, a negative regulator of STAT3, were found to be methylated in additional cohort samples, largely confined to the TET2 mutant group. Mutations in STAT3 were observed in 19 (33%) of 58 patient samples, 7 of which had concurrent TET2 mutations. Thrombocytopenia and resistance to immunosuppressive agents were uniquely observed in those patients with only TET2 mutation (Games-Howell post hoc test, P = .0074; Fisher's exact test, P = .00466). Patients with STAT3 mutation, inclusive of those with TET2 comutation, had lower hematocrit, hemoglobin, and absolute neutrophil count compared with STAT3 wild-type patients (Welch's t test, P ≤ .015). We present the discovery of TET2 mutations in chronic NK-LGL leukemia and evidence that it identifies a unique molecular subtype.

Diagnostic approach to T- and NK-cell lymphoproliferative disorders in the gastrointestinal tract.

Most gastrointestinal NK and T cell lymphomas are aggressive in behavior, although in recent years a subset of indolent lymphoproliferative disorders have been described, which must be distinguished from their more malignant mimics. Intestinal T-cell lymphomas may arise from intra-epithelial lymphocytes and display epitheliotropism, such as enteropathy-associated T-cell lymphoma and monomorphic epitheliotropic intestinal T-cell lymphoma. They are both aggressive in behavior but differ in their clinic-pathological features. On the other hand, intra-epithelial lymphocytes are not prominent in intestinal T-cell lymphoma, NOS, which is a diagnosis of exclusion and probably represents a heterogeneous group of entities. Indolent lymphoproliferative disorders of NK- and T-cells of both CD8 and CD4 subsets share a chronic, recurring clinical course but display differences from each other. CD8+ T-cell lymphoproliferative disorder of GI tract has a low proliferative fraction and does not progress nor undergo large cell transformation. Whilst NK-cell enteropathy runs an indolent clinical course, it may display a high proliferation fraction. On the other hand, CD4+ indolent T-cell lymphoproliferative disorder displays variable proliferation rates and may progress or transform after a number of years. In Asia and South America, it is not uncommon to see involvement of the gastrointestinal tract by EBV-associated extranodal NK/T cell lymphoma, nasal type, which must be distinguished from NK cell enteropathy and EBV-associated mucocutaneous ulcers.

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.

Large Granular Lymphocytosis With Cytopenias After Allogeneic Blood or Marrow Transplantation: Clinical Characteristics and Response to Immunosuppressive Therapy

Large granular lymphocytosis (LGL)-or LGL leukemia-is a T- or NK-cell lymphoproliferative disorder that often results in cytopenias and autoimmune phenomena. Several studies have described LGL in a subset of patients after allogeneic blood or marrow transplantation (alloBMT), almost exclusively in the setting of asymptomatic lymphocytosis. Some have suggested an association with improved transplant-related outcomes. In contrast, clinically significant LGL after alloBMT is only described in small case reports. This study sought to assess the characteristics, significance, and response to treatment of LGL associated with unexplained anemia, thrombocytopenia, or neutropenia after alloBMT. We performed a retrospective analysis of 150 patients who were evaluated for LGL by peripheral blood flow cytometry (LGL flow) for unexplained cytopenias following initial engraftment after alloBMT from January 1 2012 to July 1, 2019. We identified patients with abnormally increased populations of LGL cells (LGL+) as assessed by Johns Hopkins Hematopathology. We collected demographic, transplantation, and LGL treatment information from electronic medical records. We compared LGL+ patients to patients with unexplained cytopenias with negative flow cytometry for LGL (LGL-) in this cohort. We also assessed change in blood counts after 4 weeks of immunosuppressive therapy in LGL+ patients. Cytopenias occurred at a median of 5.7 months (range 1-81) after alloBMT. The majority of the transplants were nonmyeloablative from haploidentical donors, and all patients received post-transplantation cyclophosphamide for graft-versus-host disease prophylaxis, consistent with the overall alloBMT characteristics at our center. We identified 70 patients with LGL and cytopenias, representing 47% of those evaluated by flow cytometry. There were no significant demographic or transplant-related differences between LGL+ patients and LGL- patients. The median age was 59, and 63% were male. LGL+ patients were more likely to have had cytomegalovirus (CMV) viremia (73% versus 28%, P < .0001), but not acute or chronic graft-versus-host disease. LGL+ patients had higher absolute lymphocyte counts (1500 versus 485/ mm3, P < .0001), a trend toward lower absolute neutrophil count (660 versus 965/mm3, P=.17), and lower neutrophil to lymphocyte ratio (0.39 versus 1.71, P < .001). There were no differences in overall survival or relapse-free survival. Of those with T-cell LGL, 45 were assessed for T-cell receptor clonality. In all, 22% were clonal, 53% oligoclonal, 4% polyclonal, and 20% indeterminate. Thirty (43%) LGL+ patients received immunosuppressive therapy (IST) for cytopenias. First-line treatment was corticosteroids for 25 (83%). Among those treated, there was an increase in median absolute neutrophil count from 720 before treatment to 1990/mm3 after 4 weeks (P=.0017). Thrombocytopenia and anemia showed at most a mild improvement with IST. LGL was a common association with otherwise unexplained cytopenias after alloBMT, almost always after prior CMV infection. LGL in the setting of cytopenias did not predict improved transplantation outcomes compared to those with cytopenias without presence of LGL. IST was effective at improving neutropenia associated with LGL after alloBMT.