Large granular lymphocyte expansions in patients with Felty's syndrome: analysis using anti-T cell receptor V beta-specific monoclonal antibodies

Felty Syndrome Presented With Candida albicans Lung Abscess Without Arthritis: A Case Report

Felty syndrome (FS) is a late manifestation of severe active rheumatoid arthritis (RA). A high index of suspicion or FS is needed in patients who present with neutropaenia and splenomegaly with no initial or obvious identifiable cause. We present the case of a 52-year-old who presented with a one-week history of haemoptysis, fever, and night sweats. The patient was hypotensive, tachycardia, and febrile (38 °C). On examination, bilateral crackles and reduced air entry were identified on the right basal and middle zones. The patient was diagnosed with RA two years prior to this presentation and was not on a disease-modifying antirheumatic drug (DMARD). Haematology showed high inflammatory markers and pancytopenia. Chest X-ray showed a right upper lobe abscess. CT-thorax, abdomen, and pelvis confirmed lung abscesses and hepatosplenomegaly. Candida albicans was detected on the broncho-alveolar lavage. He responded well to antifungal medication and corticosteroids with normalisation of the pancytopenia and inflammatory markers and reduction of the spleen size. This case report details the unusual and early presentation of FS in a patient newly diagnosed with RA and who had no active arthritis. We wish to emphasize the importance of a high index of suspicion in patients with RA regardless of the length of their illness.

Intersection Between Large Granular Lymphocyte Leukemia and Rheumatoid Arthritis

Large granular lymphocyte (LGL) leukemia, a rare hematologic malignancy, has long been associated with rheumatoid arthritis (RA), and the diseases share numerous common features. This review aims to outline the parallels and comparisons between the diseases as well as discuss the potential mechanisms for the relationship between LGL leukemia and RA. RA alone and in conjunction with LGL leukemia exhibits cytotoxic T-cell (CTL) expansions, HLA-DR4 enrichment, RA-associated autoantibodies, female bias, and unknown antigen specificity of associated T-cell expansions. Three possible mechanistic links between the pathogenesis of LGL leukemia and RA have been proposed, including LGL leukemia a) as a result of longstanding RA, b) as a consequence of RA treatment, or c) as a driver of RA. Several lines of evidence point towards LGL as a driver of RA. CTL involvement in RA pathogenesis is evidenced by citrullination and granzyme B cleavage that modifies the repertoire of self-protein antigens in target cells, particularly neutrophils, killed by the CTLs. Further investigations of the relationship between LGL leukemia and RA are warranted to better understand causal pathways and target antigens in order to improve the mechanistic understanding and to devise targeted therapeutic approaches for both disorders.

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.

Clonal expansion of large granular lymphocytes in patients with spondyloarthritis and psoriatic arthritis treated with TNFα inhibitors

To determine the prevalence of clonal T-large granular lymphocyte (T-LGL) cells in patients with spondyloarthritis (SpA) and psoriatic arthritis (PsA) and to define possible risk factors for this condition. We present a cross-sectional analysis with retrospective and prospective aspects. 115 SpA patients, 48 PsA patients and 51 controls were recruited between December 28, 2017 and January 23, 2019. Flow cytometry (FACS) was performed to screen for aberrant T-LGL cells. Molecular analysis was then employed to confirm the diagnosis in patients with suggestive FACS findings. Patients with clonal T-LGL populations were followed prospectively by FACS analysis. Electronic patient files were retrospectively analyzed to determine risk factors. Median age was 49 years for SpA, 55.5 years for PsA, and 54 years for controls. Median disease duration of SpA and PsA was 15 years and 11 years, respectively. 79.8% of patients had received biologics at some point, 75.5% had ever received tumor necrosis factor (TNF) inhibitors. 59.5% were treated with TNF inhibitors at the time of study inclusion. We identified clonal T-LGL expansions in 13 individuals equaling a prevalence of 6% (13/214). T-LGL patients were taking TNF inhibitors more frequently at the time of study inclusion (p = 0.022) and were more likely to have ever been treated with TNF inhibition (p = 0.046). Clonal T-LGL expansions can be detected in patients with SpA, PsA and also in healthy controls. Confirming earlier results, exposure to TNFα-blocking agents appears to increase the risk of developing clonal expansions of T-LGL cells.

T-Cell Large Granular Lymphocyte Leukemia in a Patient With Rheumatoid Arthritis

Large granular lymphocyte leukemia (LGL) is a clonal, lymphoproliferative disorder with an indolent disease course. T-cell LGL (T-LGL) is the most common type of LGL driven from T-cell lineage (85%). The coexistence of T-LGL with several types of autoimmune disorders, mostly rheumatoid arthritis (RA), has been reported. Felty’s syndrome (FS) is defined by splenomegaly, low neutrophil count, and destructive arthritis and is usually seen in <1% of patients with RA. About 30% to 40% of patients with FS have been reported to have an expansion of large granulated lymphocytes in the circulation. FS and T-LGL are similar in terms of clinical manifestations, response to immunosuppressive therapy, their smoldering course, and immunogenetic findings, proposing FS and T-LGL with RA might be different aspects of a single disease spectrum. In this article, we present a case with long-standing RA who had never been on DMARD (Disease Modifying Anti-Rheumatic Drugs) treatment found to have constitutional symptoms, neutropenia, and splenomegaly, and the patient was diagnosed with T-LGL.

Neutropaenia and splenomegaly without arthritis: think rheumatoid arthritis

Felty syndrome(FS) is an uncommon, but severe, extra-articular manifestation of rheumatoid arthritis (RA). It occurs in patients with longstanding RA. It is extremely rare for RA to present as FS or develop after initially presenting as neutropaenia and splenomegaly. We describe a case of 47-year-old woman who was diagnosed simultaneously with FS and possible RA after testing positive for anticyclic citrullinated peptide antibody, but a negative rheumatoid factor. She had an excellent response to methotrexate. We review the existing literature of such cases and emphasise the importance of serological testing for RA in patients presenting with neutropaenia and splenomegaly, even in the absence of joint symptoms or prior diagnosis of RA.

Inflammatory arthritis and crystal arthropathy: Current concepts of skin and systemic manifestations

Systemic inflammatory disorders frequently involve the skin, and when cutaneous disease develops, such dermatologic manifestations may represent the initial sign of disease and may also provide valuable prognostic information about the underlying disorder. Familiarity with the various skin manifestations of systemic disease is therefore paramount and increases the likelihood of accurate diagnosis, which may facilitate the implementation of an appropriate treatment strategy. An improvement in quality of life and a reduction in the degree of morbidity may also be a realized benefit of accurate recognition of these skin signs. With this context in mind, this review highlights the salient clinical features and unique dermatologic manifestations of rheumatoid arthritis, adult-onset Still's disease, and the crystal arthropathy, gout.

Somatic STAT3 mutations in Felty syndrome: an implication for a common pathogenesis with large granular lymphocyte leukemia

Felty syndrome is a rare disease defined by neutropenia, splenomegaly, and rheumatoid arthritis. Sometimes the differential diagnosis between Felty syndrome and large granular lymphocyte leukemia is problematic. Recently, somatic STAT3 and STAT5B mutations were discovered in 30–40% of patients with large granular lymphocyte leukemia. Herein, we aimed to study whether these mutations can also be detected in Felty syndrome, which would imply the existence of a common pathogenic mechanism between these two disease entities. We collected samples and clinical information from 14 Felty syndrome patients who were monitored at the rheumatology outpatient clinic for Felty syndrome. Somatic STAT3 mutations were discovered in 43% (6/14) of Felty syndrome patients with deep amplicon sequencing targeting all STAT3 exons. Mutations were located in the SH2 domain of STAT3, which is a known mutational hotspot. No STAT5B mutations were found. In blood smears, overrepresentation of large granular lymphocytes was observed, and in the majority of cases the CD8⁺ T-cell receptor repertoire was skewed when analyzed by flow cytometry. In bone marrow biopsies, an increased amount of phospho-STAT3 positive cells was discovered. Plasma cytokine profiling showed that ten of the 92 assayed cytokines were elevated both in Felty syndrome and large granular lymphocyte leukemia, and three of these cytokines were also increased in patients with uncomplicated rheumatoid arthritis. In conclusion, somatic STAT3 mutations and STAT3 activation are as frequent in Felty syndrome as they are in large granular lymphocyte leukemia. Considering that the symptoms and treatment modalities are also similar, a unified reclassification of these two syndromes is warranted.

Atypical aleukemic presentation of large granular lymphocytic leukemia: a case report

Large granular lymphocytic leukemia (LGLL) is a rare lymphoproliferative disorder of transformed natural killer or T-cells attributed to chronic exposure to the proinflammatory cytokine IL-15. Diagnosis of the majority of T-cell LGLL is established by documenting clonal large granular lymphocytes (LGLs) in peripheral blood, by morphology and immunophenotype. The proteasome inhibitor bortezomib is known to target molecular pathways downstream of the IL-15 receptor signaling and has been proposed as a therapy in these patients. We report an uncommon presentation of LGLL with chronic neutropenia lacking typical blood LGLs, which failed to respond to bortezomib but obtained a very good partial remission with a classical methotrexate regimen.

Felty's Syndrome, Insights and Updates

Felty’s syndrome (FS) is characterized by the triad of seropositive rheumatoid arthritis (RA) with destructive joint involvement, splenomegaly and neutropenia. Current data shows that 1-3 % of RA patients are complicated with FS with an estimated prevalence of 10 per 100,000 populations. The complete triad is not an absolute requirement, but persistent neutropenia with an absolute neutrophil count (ANC) generally less than 1500/mm3 is necessary for establishing the diagnosis. Felty’s syndrome may be asymptomatic but serious local or systemic infections may be the first clue to the diagnosis. FS is easily overlooked by parallel diagnoses of Sjӧgren syndrome or systemic lupus erythematosus or lymphohematopoietic malignancies. The role of genetic (HLA DR4) is more prominent in FS in comparison to classic rheumatoid arthritis. There is large body of evidence that in FS patients, both cellular and humoral immune systems participate in neutrophil activation, and apoptosis and its adherence to endothelial cells in the spleen. It has been demonstrated that proinflammatory cytokines may have inhibitory effects on bone marrow granulopoiesis. Binding of IgGs to neutrophil extracellular chromatin traps (NET) leading to neutrophil death plays a crucial role in its pathophysiology. In turn, "Netting" neutrophils may activate auto-reactive B cells leading to further antibody and immune complex formation. In this review we discuss on basic pathophysiology, epidemiology, genetics, clinical, laboratory and treatment updates of Felty’s syndrome.

T-large granular lymphocyte leukemia: current molecular concepts

T-large granular lymphocyte (T-LGL) leukemia is a chronic and often indolent T cell lymphoproliferation characterized by extreme expansion of a semi-autonomous cytotoxic T lymphocyte (CTL) clone. Clinically, T-LGL can be associated with various cytopenias; neutropenia constitutes the most frequent manifestation. LGL clone represents a pathologic counterpart of the cytotoxic effector T cell but an abnormal memory CD8 cell seems to provide the supply of the matured LGL population. Analysis of clonal T cell receptor (TCR) rearrangement and complementarity determining region 3 (CDR3) of the TCR beta-chain is a useful tool to investigate clonal expansions, track the frequency of expanded clones and also clinically useful to monitor the response to therapy. The lessons learned from molecular analysis of clonal repertoire support a clinically-derived conclusion that the LGL clone arises in the context of an initially polyclonal immune response or an autoimmune process. Consequently, specific manifestations of T-LGL may be a result of the recognition spectrum of the transformed clone and the cytokines it produces. Due to the often monoclonal manifestation, T-LGL constitutes a suitable model to investigate polyclonal CTL-mediated processes. Application of new technologies, including TCR repertoire analysis by sequencing, clonotypic quantitative PCR and VB flow cytometry facilitate clinical diagnosis and may allow insights into the regulation of TCR repertoire and consequences resulting from the contraction of clonal diversity.

Autoimmune manifestations in large granular lymphocyte leukemia

Large granular lymphocyte (LGL) leukemia features a group of indolent lymphoproliferative diseases that display a strong association with various autoimmune conditions. Notwithstanding, these autoimmune conditions have not been comprehensively characterized or systematized to date. As a result, their clinical implications remain largely unknown. The authors offer a comprehensive review of the existing literature on various autoimmune conditions documented in the course of T-cell LGL (T-LGL) leukemia. Though some of them are thought be secondary to the LGL leukemia, others could be primary and might even play a role in its pathogenesis. A considerable clinico-laboratory overlap between T-LGL leukemia associated with rheumatoid arthritis and Felty's syndrome suggests that they are just different eponyms for the same clinical entity.

The spectrum of large granular lymphocyte leukemia and Felty's syndrome

PURPOSE OF REVIEW

Patients with chronic large granular lymphocyte (LGL) leukemia often have rheumatoid arthritis (RA), neutropenia and splenomegaly, thereby resembling the manifestations observed in patients with Felty's syndrome, which is a rare complication of RA characterized by neutropenia and splenomegaly. Both entities have similar clinical and laboratory presentation, as well as a common genetic determinant, HLA-DR4, indicating they may be part of the same disease spectrum. This review paper seeks to discuss the underlying pathogenesis and therapeutic algorithm of RA, neutropenia and splenomegaly in the spectrum of LGL leukemia and Felty's syndrome.

RECENT FINDINGS

We hypothesize that there may be a common pathogenic mechanism between LGL leukemia and typical Felty's syndrome. Phenotypic and functional data have strongly suggested that CD3 LGL leukemia is antigen-activated. Aberrations in the T-cell repertoire with the emergence of oligoclonal/clonal lymphoid populations have been found to play a pivotal role in pathogenesis of RA. The biologic properties of the pivotal T cell involved in RA pathogenesis are remarkably similar to those in leukemic LGL.

SUMMARY

RA-associated T-cell LGL leukemia and articular manifestations of typical Felty's syndrome are not distinguishable. A common pathogenetic link between LGL leukemia and RA is proposed.

T cell large granular lymphocyte leukemia associated with rheumatoid arthritis and neutropenia

T cell large granular lymphocyte leukemia (T-LGL) is a disease characterized by clonal expansion of cytotoxic T cells (CTLs). It generally follows an indolent course and is notable for an association with chronic inflammation, neutropenia and rheumatoid arthritis (RA). We present herein a case of a patient with rheumatoid arthritis (RA), neutropenia, large granular lymphocytosis, and an expanded clonal population of peripheral blood CD3(+)CD8(+)TCRalphabeta CTLs, consistent with the diagnosis of T-LGL. T-LGL is part of a spectrum of large granular lymphocytic (LGL) disorders, which includes the more common indolent variety of this disease (as illustrated by the case herein), an aggressive but rare form of this leukemia, natural killer (NK) cell LGL leukemia, Felty's syndrome (FS), and chronic large granular lymphocytosis. T-LGL appears to be a relatively rare disease, but the true prevalence is not known. FS occurs in less than 1% of patients with RA and is typically defined by the triad of destructive arthritis, neutropenia, and variable splenomegaly. A subset of patients with FS will demonstrate polyclonal expansion of LGLs, implying a relationship between proliferation of LGLs and the mechanisms of neutropenia. Thus, T-LGL leukemia and FS with LGL expansion in the setting of RA is classically distinguished by the clonality of the CTL population, with monoclonality in T-LGL and polyclonality in FS. Despite this difference, T-LGL and FS are often similar in their clinical and biological behavior. Both may respond to immunosuppressive therapy, and pursue a smoldering course typical of a chronic inflammatory disease.

Molecular strategies for detection and quantitation of clonal cytotoxic T-cell responses in aplastic anemia and myelodysplastic syndrome

Immune mechanisms are involved in the pathophysiology of aplastic anemia (AA) and myelodysplastic syndrome (MDS). Immune inhibition can result from cytotoxic T cell (CTL) attack against normal hematopoiesis or reflect immune surveillance. We used clonally unique T-cell receptor (TCR) variable beta-chain (VB) CDR3 regions as markers of pathogenic CTL responses and show that while marrow failure syndromes are characterized by polyclonal expansions, overexpanded clones exist in these diseases and can serve as investigative tools. To test the applicability of clonotypic assays, we developed rational molecular methods for the detection of immunodominant clonotypes in blood and in historic marrow biopsies of 35 AA, 37 MDS, and 21 paroxysmal nocturnal hemoglobinuria (PNH) patients, in whom specific CDR3 sequences and clonal sizes were determined. CTL expansions were detected in 81% and 97% of AA and MDS patients, respectively. In total, 81 immunodominant signature clonotypes were identified. Based on the sequence of immunodominant CDR3 clonotypes, we designed quantitative assays for monitoring corresponding clones, including clonotypic Taqman polymerase chain reaction (PCR) and clonotype-specific sequencing. No correlation was found between clonality and disease severity but in patients treated with immunosuppression, truly pathogenic clones were identified based on the decline that paralleled hematologic response. We conclude that immunodominant clonotypes associated with marrow failure may be used to monitor immunosuppressive therapy.

Pathologic clonal cytotoxic T-cell responses: nonrandom nature of the T-cell–receptor restriction in large granular lymphocyte leukemia

T-cell large granular lymphocyte (T-LGL) leukemia is a clonal lymphoproliferation of cytotoxic T cells (CTLs) associated with cytopenias. T-LGL proliferation seems to be triggered/sustained by antigenic drive; it is likely that hematopoietic progenitors are the targets in this process. The antigen-specific portion of the T-cell receptor (TCR), the variable beta (VB)–chain complementarity-determining region 3 (CDR3), can serve as a molecular signature (clonotype) of a T-cell clone. We hypothesized that clonal CTL proliferation develops not randomly but in the context of an autoimmune response. We identified the clonotypic sequence of T-LGL clones in 60 patients, including 56 with known T-LGL and 4 with unspecified neutropenia. Our method also allowed for the measurement of clonal frequencies; a decrease in or loss of the pathogenic clonotype and restoration of the TCR repertoire was found after hematologic remission. We identified 2 patients with identical immunodominant CDR3 sequence. Moreover, we found similarity between multiple immunodominant clonotypes and codominant as well as a nonexpanded, “supporting” clonotypes. The data suggest a nonrandom clonal selection in T-LGL, possibly driven by a common antigen. In contrast, the physiologic clonal CTL repertoire is highly diverse and we were not able to detect any significant clonal sharing in 26 healthy controls.

Primary and secondary autoimmune neutropenia

Antineutrophil antibodies are well recognized causes of neutropenia, producing both quantitative and qualitative defects in neutrophils and increased risk for infection. In primary autoimmune neutropenia (AIN) of infancy, a moderate to severe neutropenia is the sole abnormality; it is rarely associated with serious infections and exhibits a self-limited course. Chronic idiopathic neutropenia of adults is characterized by occurrence in late childhood or adulthood, greater prevalence among females than among males, and rare spontaneous remission. Secondary AIN is more commonly seen in adults and underlying causes include collagen disorders, drugs, viruses and lymphoproliferative disorders. In most patients with AIN, antibodies recognize antigens located on the IgG Fc receptor type 3b but other target antigens have been recently identified in secondary AIN. Granulocyte colony-stimulating factor is a proven treatment in patients with AIN of all types and is now preferred to other possible therapies.

Large granular lymphocyte (LGL)-like clonal expansions in paroxysmal nocturnal hemoglobinuria (PNH) patients

In paroxysmal nocturnal hemoglobinuria (PNH), clonal expansion of glycosylphosphatidylinositol-anchored proteins (GPI-AP)-deficient cells leads to a syndrome characterized by hemolytic anemia, marrow failure, and venous thrombosis. PNH is closely related to aplastic anemia and may share its immune pathophysiology. In vivo expansion of dominant T-cell clones can reflect an antigen-driven immune response but may also represent autonomous proliferation, such as in large granular lymphocytic (LGL)-leukemia. T-cell clonality can be assessed by a combination of T-cell receptor (TCR) flow cytometry and complementarity-determining-region-3 (CDR3) molecular analysis. We studied 24 PNH patients for evidence of in vivo dominant T-cell responses by flow cytometry; TCR-Vbeta-specific expansions were identified in all patients. In four cases, extreme expansions of one Vbeta-subset of CD8+/CD28-/CD56+ (effector) phenotype mimicked subclinical LGL-disease. The monoclonality of these expansions was inferred from unique CDR3-size peak distributions and sequencing of dominant clonotypes. We conclude that the molecular analysis of TCR-beta chain may demonstrate clonal LGL-like expansions at unexpected frequency in PNH patients. Our observations blur the classical boundaries between different bone marrow failure syndromes such as AA, PNH, and LGL, and support the hypothesis that in PNH, the mutant clone may expand as a result of an immune-escape from antigen-driven lymphocyte attack on hematopoietic progenitors.

Chronic neutropenia associated with autoimmune disease

Chronic neutropenia with autoimmune diseases is associated mainly with rheumatoid arthritis (RA), as Felty's syndrome or large granular lymphocyte (LGL) leukemia, and with systemic lupus erythematosus (SLE). Recent advances have allowed better understanding regarding the mechanism of neutropenia and improved options for treatment. Target antigens for antineutrophil antibodies have been identified for both Felty's syndrome and for SLE. The role of soluble Fas-ligand (FasL) in inducing apoptosis of neutrophils has been clarified for LGL leukemia and increased neutrophil apoptosis has been described in neutropenic patients with SLE. The role of immune complexes in affecting neutrophil traffic and function continues to be studied. Treatments of neutropenia have included methotrexate, cyclosporine A, and granulocyte colony-stimulating factor (G-CSF) as well as granulocyte-macrophage colony-stimulating factor (GM-CSF). The efficacy of both GM- and G-CSF in reversing neutropenia and decreasing the risk of infections in Felty's syndrome and SLE has been well documented. Of concern, however, have been flares of symptoms or development of leukocytoclastic vasculitis in some patients following the use of these cytokines. Recent results suggest that in these patients G-CSF should be administered at the lowest dose effective at elevating the neutrophil count above 1,000/microL.

CD8+CD28- T cells: certainties and uncertainties of a prevalent human T-cell subset

Human peripheral blood CD8+ T cells comprise cells that are in different states of differentiation and under the control of complex homeostatic processes. In a number of situations ranging from chronic inflammatory conditions and infectious diseases to ageing, immunodeficiency, iron overload and heavy alcohol intake, major phenotypic changes, usually associated with an increase in CD8+ T cells lacking CD28 expression, take place. CD8+CD28- T cells are characterized by a low proliferative capacity to conventional stimulation in vitro and by morphological and functional features of activated/memory T cells. Although the nature of the signals that give origin to this T-cell subset is uncertain, growing evidence argues for the existence of an interplay between epithelial cells, molecules with the MHC-class I fold and CD8+ T cells. The possibility that the generation of CD8+CD28- T cells is the combination of TCR/CD3zeta- and regulatory factor-mediated signals as a result of the sensing of modifications of the internal environment is discussed.

Immunophenotypic analysis of the TCR-Vbeta repertoire in 98 persistent expansions of CD3(+)/TCR-alphabeta(+) large granular lymphocytes: utility in assessing clonality and insights into the pathogenesis of the disease

At present, a major challenge in the initial diagnosis of leukemia of large granular lymphocytes (LGLs) is to establish the clonal nature of the expanded population. In the present study we have analyzed by flow cytometry immunophenotyping the TCR-Vbeta repertoire of 98 consecutive cases of persistent expansions of CD4(+) or CD8(+bright) CD3(+)/TCR-alphabeta(+) LGLs and compared the results with those obtained in molecular studies of TCR-beta gene rearrangements. Fifty-eight cases were considered to be monoclonal in molecular studies whereas in the remaining 40 cases there was no evidence for monoclonality (11 cases were considered oligoclonal and 29 polyclonal). The TCR-Vbeta repertoire was biased to the preferential use of one or more TCR-Vbeta families in 96% of cases, a total of 124 TCR-Vbeta expansions being diagnosed: one TCR-Vbeta expansion in 71 cases and two or more TCR-Vbeta expansions in 23 cases. The highest TCR-Vbeta expansion observed in each case was higher among monoclonal (74 +/- 19%) as compared to nonmonoclonal cases (24 +/- 14%) (P = 0.001), as did the fraction of LGLs that exhibited a TCR-Vbeta-restricted pattern (86 +/- 16% and 42 +/- 23%, respectively; P = 0.0001); by contrast, the proportion of cases displaying more than one TCR-Vbeta expansion was higher in the latter group: 7% versus 48%, respectively (P = 0.001). Results obtained in oligoclonal cases were intermediate between those obtained in polyclonal and monoclonal cases and similar results were observed for CD4(+) as for CD8(+bright) T-cell expansions. TCR-Vbeta families expressed in CD8(+bright) T-cell-LGL proliferations showed a pattern of distribution that mimics the frequency at which the individual TCR-Vbeta families are represented in normal peripheral blood T cells. Assuming that a given proliferation of LGLs is monoclonal whenever there is an expansion of a given TCR-Vbeta family of at least 40% of the total CD4(+) or CD8(+bright) T-cell compartment, we were able to predict clonality with a sensitivity of 93% and a specificity of 80%. By increasing the cut-off value to 60%, sensitivity and specificity were of 81% and 100%. In summary, our results suggest that flow cytometry immunophenotypic analysis of the TCR-Vbeta repertoire is a powerful screening tool for the assessment of T-cell clonality in persistent expansions of TCR-alphabeta(+) LGLs.

Peripheral T/NK-cell lymphoma: a report of the IXth Workshop of the European Association for Haematopathology

AIMS

In April 1998, The European Association for Haematopathology organized the IXth workshop on peripheral T-cell and NK-cell lymphomas and leukaemias. The workshop focused on unusual subtypes of these rare malignancies, allowing evaluation of the recently published WHO classification of neoplastic diseases of the lymphoid tissues.

METHODS AND RESULTS

One-hundred and three cases were centrally immunophenotyped and hybridized for EBER1/2 of Epstein--Barr virus. All cases were reviewed by a panel of experienced haematopathologists and classified according to the new WHO classification for lymphoid neoplasms. Three cases were considered as precursor T-cell and 95 cases as peripheral T/NK-cell lymphoma/leukaemia. Although the cases represented a selected series of unusual cases, the following conclusions could be made: (i) Most lymphomas except the hepatosplenic gamma/delta T-cell lymphomas showed a rather broad morphological spectrum, with differences both between and within individual tumours. (ii) This heterogeneity was also reflected by the immunophenotype, for instance a variable expression of CD30 was found in many enteropathy type T-cell lymphomas. (iii) Exceptions in phenotype were regularly found in almost all categories, indicating that phenotype should not be the final determining factor in classification. (iv) The great majority of T-cell lymphomas expressed the alpha/beta T-cell receptor, with the exception of all but one hepatosplenic T-cell lymphomas and a few other extranodal peripheral T cell lymphomas. (v) Malignancies of precursor cells, blastic NK-cell lymphoma/leukaemia, adult T-cell lymphoma/leukaemia and most AIL-type T-cell lymphomas did not express cytotoxic molecules such as TIA1 and granzyme-B. In contrast, all five aggressive NK/T-cell lymphomas/leukaemias, a single case of large granular lymphocyte leukaemia and 40 of 47 primary extranodal lymphoma/leukaemias expressed these molecules. In hepatosplenic gamma/delta T-cell lymphoma, five of six cases showed expression of TIA1 but not of granzyme-B. (vi) Seven tumours developed after organ-transplant, four cases being EBV-positive. No distinct phenotype could be attributed to these cases.

CONCLUSIONS

Most peripheral T/NK cell lymphomas could be categorized as distinct entities as described in the recently proposed WHO classification for lymphoid neoplasms.

A Fas promoter polymorphism at position -670 in the enhancer region does not confer susceptibility to Felty's and large granular lymphocyte syndromes

OBJECTIVE

We examined whether there are associations between a polymorphism in the Fas promoter, recently found to be associated with rheumatoid arthritis (RA), and Felty's syndrome or large granular lymphocyte (LGL) leukaemia.

METHODS

Thirty-five patients with Felty's were studied, along with 18 patients with LGL syndrome and arthritis, 17 patients with LGL syndrome but no arthritis, and 128 controls. The polymorphism was typed by polymerase chain reaction followed by digestion with the restriction enzyme MvaI.

RESULTS

No significant difference was found in genotype or allele frequencies between the groups.

CONCLUSION

This promoter polymorphism is not a significant risk factor responsible for the LGL expansions seen in Felty's and LGL syndromes. Abnormal, constitutive expression of Fas ligand may be more relevant to the aetiology of these diseases.

T cell receptor alpha-chain and beta-chain junctional region homology in clonal CD3+, CD8+ T lymphocyte expansions in Felty's syndrome

OBJECTIVE

Up to 42% of patients with Felty's syndrome (FS) have peripheral blood expansions of CD3+,CD8+ large granular lymphocytes (LGLs). The aim of this study was to determine whether the T cell receptor (TCR) alpha- and beta-chain sequences of these expansions from different patients have features in common that would support the hypothesis of an antigen-driven process.

METHODS

Extraction of RNA from peripheral blood lymphocytes followed by synthesis of complementary DNA, inverse polymerase chain reaction (PCR) with TCR-specific primers, bacteriophage transformation, and sequencing of PCR products.

RESULTS

Structural analysis of TCR beta-chain usage in such patients demonstrated a junctional region motif comprising the amino acids -LG- or -RG- in 7 of 14 clonal sequences and the motif -GXG- in 8 of 14. A biased alpha-chain junctional region usage of a hydrophobic and/or basic amino acid at position 2 was seen in 5 of 8 expanded sequences. These features differed significantly from control sequences.

CONCLUSION

Given current models of TCR-peptide-major histocompatibility complex interaction, these observations are consistent with an antigen-driven, rather than a superantigen-driven, process in at least a subgroup of patients with FS.

An unusual association of Felty syndrome and TCR gamma delta lymphocytosis

Felty syndrome, comprised of neutropenia, rheumatoid arthritis and splenomegaly, occurs in approximately 1% of patients with rheumatoid arthritis. Up to one third of these patients have an increased number of large granular lymphocytes. The usual immunophenotype of these cells is CD3+, CD8+, CD57+, T cell receptor (TCR) alpha beta. A patient with Felty syndrome and large granular lymphocytosis, who had an unusual immunophenotype CD3+, CD4-, CD8-, TCR gamma delta, is described. Her neutropenia responded to treatment with granulocyte colony stimulating factor (G-CSF), which was given in order to raise her neutrophil count prior to bilateral knee replacement surgery. Thus, Felty syndrome with large granular lymphocytosis is a heterogeneous condition, one in which TCR gamma delta large granular lymphocytosis may be found, and also shows a response to treatment with G-CSF.

Hematologic and cytofluorographic analysis of patients with Felty's syndrome. A hypothesis that a discrete event leads to large granular lymphocyte expansions in this condition

OBJECTIVE

To compare hematologic and cytofluorographic features in Felty's syndrome (FS) patients with and without the large granular lymphocyte (LGL) syndrome.

METHODS

Peripheral blood cells from FS patients and from 2 control groups (rheumatoid arthritis [RA] patients and subjects without symptoms of a rheumatic disease) were analyzed by hematologic and cytofluorographic techniques. A separate assessment of disease activity was performed.

RESULTS

FS patients had reduced lymphocyte and platelet counts, with a parallel reduction in lymphocyte subsets examined. CD4 counts were reduced in all FS patients, including those with the LGL syndrome. Disease activity was lower in FS patients than in RA control patients. Treatment was similar in all patient groups. No direct association was seen between LGL numbers and duration of RA or neutrophil counts in RA groups.

CONCLUSION

Hematologic abnormalities in FS extend beyond neutropenia. Although similarities were seen between FS patients and FS patients with the LGL syndrome (e.g., CD4 lymphopenia), evidence for a gradation from FS to the LGL syndrome was not seen, thus favoring the hypothesis that a "transforming event" is required.