Distinctive clinical characteristics and favorable outcomes in patients with large granular lymphocytosis after allo-HCT: 12-year follow-up data

T-Cell Lymphoproliferative Disorders Following Allogeneic Bone Marrow Transplant: A Report of Two Cases and a Literature Review

Post-transplantation lymphoproliferative disorders (PTLD) are a commonly occurring condition following solid organ transplantation (SOT) and, rarely, hematopoietic stem cell transplantation (HSCT). As the name suggests, a PTLD is a condition where there is a clonal proliferation of lymphoid cells that occurs as a complication after transplantation. Though the clonal origin cell is primarily associated with the B-cell lineage, there are existing cases in the literature describing PTLD from the T-cell lineage. Large granulocytic leukemia (LGL) is one rare T-cell lineage subtype that typically progresses with a passive clinical course and is discovered with leukocytosis and peripheral blood smears demonstrating large granules in lymphocytes. In this study, we describe two patients initially diagnosed with acute myeloid leukemia (AML) who were both found to have T-cell PTLD after undergoing allogeneic hematopoietic stem cell transplant. One was found with a clonal expansion of T-cells on flow cytometry and the other with LGL on peripheral blood and flow cytometry. This discovery was made at 16 and 20 months after their transplant respectively. Distinguishing factors for these two patients are demonstrated by the derivation of lymphoproliferative disorder from graft vs. host disease (GVHD) or viral etiology, which is significant as both of which have been shown to be associated with PTLD. Epstein-Barr virus (EBV) and cytomegalovirus (CMV) positivity have been shown to be associated with PTLD, and both our patients were EBV-negative but had harbored prior CMV infections. Additionally, they had a benign course with no development of cytopenias or symptoms since the time of diagnosis. These two cases add to the growing literature that is working to better characterize the rare development of LGL and, in general, T-cell PTLD following allogeneic bone marrow transplantation.

Persistent Large Granular Lymphocyte Clonal Expansions: “The Root of Many Evils”—And of Some Goodness

Simple Summary

Large granular lymphocyte leukemia (LGLL) is a chronic disorder of either mature T or NK lymphocytes. As clonal expansions of the immune system cells, difficulties in the distinction between a true neoplasia and a physiological reactive process have been common since its description. We review here the different conditions associated with persistent clonal LGL expansions and discuss their potential origin and whether they can modulate the clinical features.

Abstract

Large granular lymphocyte leukemia (LGLL) is a chronic disease of either mature phenotype cytotoxic CD3+ T lymphocytes or CD3- NK cells. LGLL diagnosis is hampered by the fact that reactive persistent clonal LGL expansions may fulfill the current criteria for LGLL diagnoses. In addition to the presence of characteristic clinical and hematological signs such as anemia or neutropenia, LGLL/LGL clonal expansions have been associated with an array of conditions/disorders. We review here the presence of these persistent clonal expansions in autoimmune, hematological disorders and solid neoplasms and after hematopoietic stem cell transplantation. These associations are a unique translational research framework to discern whether these persistently expanded LGL clones are causes or consequences of the concomitant clinical settings and, more importantly, when they should be targeted.

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.

[Clinical features and risk factors analyses of patients with T cell large granular lymphocytosis following allo-HSCT]

目的

探讨异基因造血干细胞移植（allo-HSCT）后发生T大颗粒淋巴细胞增多（T-LGL）患者的临床特征、相关因素以及对预后的影响。

方法

回顾性分析2013年6月至2020年2月接受allo-HSCT的359例患者连续性资料，男216例，女143例，中位年龄为38（7~65）岁。分析T-LGL的临床特征、累积发生率，比较发生与未发生T-LGL患者的总生存（OS）率、无病生存（DFS）率、累积复发率（CIR）及非复发死亡率（NRM）的差异，并研究影响移植后发生T-LGL的相关因素。

结果

共入组359例患者，T-LGL组17例，非LGL组342例，中位随访38（3~92）个月，移植后1、2、3年T-LGL累积发生率分别为3.64%（95%CI 1.09%~6.19%）、4.50%（95%CI 1.36%~7.64%）和4.84%（95%CI 1.10%~8.76%）；移植受者CMV再激活（P=0.013）、EBV血症（P=0.034）以及急性移植物抗宿主病（P=0.027）均与T-LGL发生有关，且多因素分析显示，良性血液病[P=0.027，OR=3.36（95%CI 1.15~9.89）]、单倍型移植[P=0.030，OR=4.67（95%CI 1.16~18.75）]、无关供者移植[P=0.041，OR=5.49（95%CI 1.10~28.16）]为移植后发生T-LGL的独立预测因素。两组患者移植后3年OS、DFS率、CIR以及NRM差异均有统计学意义[OS：100.0%对78.6%（95%CI 74.1%~83.1%），P=0.04；DFS：100.0%对70.0%（95%CI 64.9%~75.1%），P=0.01；CIR：0对16.1%（95%CI 11.8%~22.4%），P<0.01；NRM：0对12.6%（95%CI 12.5%~12.6%），P=0.02]。亚组分析结果显示，恶性疾病患者移植后发生T-LGL者预后良好，NRM、DFS率以及CIR差异均有统计学意义（P值均<0.05），而良性疾病患者移植后发生T-LGL对预后无明显影响。

结论

恶性疾病患者移植后T-LGL可能是一个较为持久的良性临床过程，与免疫重建和T细胞调节机制相关的因素可作为移植后T-LGL发生的主要预测因素。

Mass Cytometry for the Assessment of Immune Reconstitution After Hematopoietic Stem Cell Transplantation

Mass cytometry, or Cytometry by Time-Of-Flight, is a powerful new platform for high-dimensional single-cell analysis of the immune system. It enables the simultaneous measurement of over 40 markers on individual cells through the use of monoclonal antibodies conjugated to rare-earth heavy-metal isotopes. In contrast to the fluorochromes used in conventional flow cytometry, metal isotopes display minimal signal overlap when resolved by single-cell mass spectrometry. This review focuses on the potential of mass cytometry as a novel technology for studying immune reconstitution in allogeneic hematopoietic stem cell transplant (HSCT) recipients. Reconstitution of a healthy donor-derived immune system after HSCT involves the coordinated regeneration of innate and adaptive immune cell subsets in the recipient. Mass cytometry presents an opportunity to investigate immune reconstitution post-HSCT from a systems-level perspective, by allowing the phenotypic and functional features of multiple cell populations to be assessed simultaneously. This review explores the current knowledge of immune reconstitution in HSCT recipients and highlights recent mass cytometry studies contributing to the field.