Adult-onset cyclic neutropenia is a benign neoplasm associated with clonal proliferation of large granular lymphocytes

Episodic angioedema with eosinophilia (Gleich syndrome) is a multilineage cell cycling disorder

Episodic angioedema with eosinophilia (Gleich syndrome) is a rare disorder characterized by episodes of angioedema and eosinophilia that occur at monthly intervals and resolve spontaneously without therapy. Despite the striking periodicity of this disorder, its similarity to other cyclic hematopoietic disorders with multilineage involvement has not been assessed. To characterize the involvement of cell lineages in the etiology and pathogenesis of episodic angioedema with eosinophilia, four subjects were evaluated by blood counts and other analyses over the course of 1-2 months. Surface marker expression was assessed on T cells by flow cytometry and clonality by polymerase chain reaction. Intracellular cytokine evaluation, bone marrow and skin biopsies were performed during different parts of the cycle. Cycling of multiple cell lineages, including neutrophils, lymphocytes and eosinophils, was observed in the four subjects with the disorder with a periodicity of 25-35 days. An aberrant CD3(-)CD4(+) T-cell population was detected in all four subjects, and T-cell receptor rearrangement studies showed a clonal pattern in three subjects. A peak of type II cytokines was detected in the serum of subjects prior to the onset of symptoms and eosinophil cycling and corresponded to ex-vivo type II cytokines detected intracellularly in CD3(+)CD4(+)CD154(+) T cells. Although the etiology of episodic angioedema with eosinophilia is not yet known, multiple lineages, including lymphocytes, neutrophils and mast cells, are involved and may be related to disease pathogenesis. Whether these cells act directly or promote eosinophilia and eosinophil activation remains to be elucidated. All subjects gave informed consent and were evaluated under an Institutional Review Board-approved protocol (NCT00001406).

Pathophysiologic mechanisms and management of neutropenia associated with large granular lymphocytic leukemia

Large granular lymphocyte (LGL) syndrome includes a spectrum of clonal T cell and natural killer cell chronic lymphoproliferative disorders. These conditions are thought to arise from chronic antigenic stimulation, while the long-term survival of the abnormal LGLs appears to be sustained by resistance to apoptosis and/or impaired survival signaling. T-cell LGL (T-LGL) leukemia is the most common LGL disorder in the Western world. Despite its indolent course, the disease is often associated with neutropenia, the pathogenesis of which is multifactorial, comprising both humoral and cytotoxic mechanisms. This article addresses the pathogenesis of T-LGL leukemia and natural killer cell chronic lymphoproliferative disorder, as well as that of T-LGL leukemia-associated neutropenia. Furthermore, as symptomatic neutropenia represents an indication for initiating treatment, available therapeutic options are also discussed.

The root of many evils: indolent large granular lymphocyte leukaemia and associated disorders

Large granular lymphocytes (LGL) leukaemia can arise from either natural killer (NK) cells or cytotoxic T lymphocytes (CTL). The T-cell form of LGL leukaemia has significant overlap with other haematological disorders and autoimmune diseases. Here we provide an overview of LGL biology. We also focus discussion on the indolent LGL leukaemia related disorders and their causal relationships. We then discuss the potential relationships and distinctions between indolent LGL leukaemia and non-malignant clonal lymphocyte expansion that occur in otherwise healthy individuals, especially elder people.

Clonal predominance of CD8(+) T cells in patients with unexplained neutropenia

OBJECTIVE

T-cell-mediated autoimmunity may be involved in some cases of idiopathic neutropenia. We hypothesized that a precise T-cell receptor repertoire analysis may uncover cytotoxic T-cell (CTL) expansions that are less pronounced than those seen in T large granular lymphocyte leukemia (T-LGL), but are pathophysiologically analogous and thus can serve as markers of a T-cell-mediated process.

MATERIALS AND METHODS

Using rational algorithms for T-cell receptor analysis and in vivo tracking of CTL responses previously established in our laboratory, we studied patients with unexplained chronic neutropenia (n = 20), T-LGL (n = 15), and healthy controls (n = 12). We further investigated the involvement of soluble inhibitory factors by coculture assays. To determine the level of immune activation, we studied interferon-gamma expression in CD8(+)cells using Taqman polymerase chain reaction.

RESULTS

Fifteen expanded (immunodominant) CTL clones were detected in 12 of 20 patients. In comparison to LGL leukemia, these clones were less immunodominant, but clearly discernible from subclinical lymphoproliferations in controls. As a surrogate of cytotoxic activity, we found markedly increased production of interferon-gamma in most of the neutropenia patients, irrespective of the presence of immunodominant CTL clones.

CONCLUSIONS

These results suggest that, while immunodominant CTL clones are detectable in a proportion of patients only, CTL-mediated pathophysiology may be a general mechanism operating in idiopathic neutropenia. Oligogoclonal CTL expansions in chronic neutropenia may indicate an ongoing autoimmune process, while highly polarized monoclonalities in a subset of neutropenic LGL patients may represent the "extreme" end of the clonal continuum.

Cyclic neutropenia

Cyclic neutropenia is a rare hematologic disorder, characterized by repetitive episodes of fever, mouth ulcers, and infections attributable to recurrent severe neutropenia. Fluctuations in blood cells are due to oscillatory production of cells by the bone marrow. Recent genetic, molecular, and cellular studies have shown that autosomal-dominant cyclic neutropenia and sporadic cases of this disease are due to a mutation in the gene for neutrophil elastase (ELA2), located at 19p13.3. This enzyme is synthesized in neutrophil precursors early in the process of primary granule formation. It is currently presumed that the mutant neutrophil elastase functions aberrantly within the cells to accelerate apoptosis of the precursors, resulting in effective and oscillatory production. Cyclic neutropenia is effectively treated with granulocyte colony-stimulating factor (G-CSF), usually at doses of 1 to 5 microg/kg/d (median dose, 2.5 microg/kg/d). Long-term, daily, or alternate-day administration reduces fever, mouth ulcers, and other inflammatory events associated with this disorder. Leukemic transformation is not a recognized risk for cyclic neutropenia, with or without treatment with G-CSF.

T Cell and NK Cell Lymphoproliferative Disorders

This review covers the diagnosis and management of natural killer and peripheral T-cell lymphomas (PTCL). Problems with PTCL include their rarity, representing usually 10-15% of non-Hodgkin's lymphomas in the Western Hemisphere, morphologic heterogeneity, and lack of immunophenotypic markers for clonality. Additionally, their clinical behavior is variable and may not correlate with morphology.

Dr. Kinney gives a general overview of the diagnosis of PTCL and NK cell neoplasms. Emphasis will be placed on extranodal T cell and natural killer (NK) cell lymphomas such as hepatosplenic lymphoma, subcutaneous panniculitis-like lymphoma and nasal/nasal type T/NK-cell lymphoma. The use of ALK gene regulation in the classification of anaplastic large cell lymphoma is also reviewed.

Dr. Loughran describes current understanding of the pathogenesis of large granular lymphocyte (LGL) leukemia. The discussion focuses on LGL leukemia as an instructive model of dysregulated apoptosis causing both malignant and autoimmune disease. Current management options and mechanisms of therapeutic response are also described.

Dr. Greer addresses whether PTCL should be treated differently from the more common diffuse large B cell lymphomas. He discusses the therapeutic options for anaplastic large cell lymphoma (ALCL), from a conservative approach for primary cutaneous ALCL to combination chemotherapy for the highly chemosensitive ALCL expressing anaplastic lymphoma kinase. He reviews therapy options for the extranodal subtypes of PTCL by drawing from series in adults, pediatrics, dermatology, and the Far East.

Current concepts: large granular lymphocyte leukemia

Clonal diseases of large granular lymphocyte (LGL) disorders can arise from a CD3+ T-cell lineage or from a CD3- NK-cell lineage. CD3+ LGL leukemia is the most frequent form of LGL leukemia. T-LGL leukemia usually affects elderly people. Approximately 60% of patients are symptomatic; recurrent infections secondary to chonic neutropenia, anemia, and rheumatoid arthrititis are the main clinical manifestations. The most common phenotype is CD3+, alphabeta+, CD8+, CD57+. Clonality is detected by clonal rearrangement of the T-cell receptor gene. NK-cell LGL proliferative disorders include NK LGL leukemia which is a very aggressive disease and NK chronic lymphocytosis. Serologic findings show frequent reactivity to the BA21 epitope of HTLV-I env p21e, suggesting that a cellular or retroviral protein with homology to BA21 may be important in pathogenesis of these diseases. Clonal expansion may be facilitated by IL12 and IL15 cytokines expressed by leukemic LGL, and also by a defective Fas (CD95) apoptotic pathway. Leukemic LGL constitutively express Fas and Fas-Ligand but they are resistant to Fas-induced apotosis. Neutropenia could be due to soluble Fas-Ligand which is highly secreted in the patient's sera. Clinical and molecular remission can be obtained with oral low-dose methotrexate. Leukemic LGL express a multi-drug resistance phenotype (PgP+/LRP+) that could partly explain the chemoresistance observed in aggressive cases. It is suggested that LGL leukemia can serve as a useful model of dysregulated apoptosis as an underlying mechanism for both malignancy and autoimmune disease.

Clonal T cell proliferation in patients with pure red cell aplasia

Among the patients with idiopathic pure red cell aplasia (PRCA) who do not meet the diagnostic criteria of chronic lymphocytic leukemia, there are some cases which suggest an association with clonal T lymphocytic proliferation. The morphological characteristics and responses to treatment revealed two distinct groups among the present 13 patients. The lymphocytes in one group were typical granular lymphocytes of T cell phenotype which were treated effectively with cyclophosphamide rather than cyclosporine. The response to therapy in this group occurred after a perceptible reduction in lymphocyte mass, which took at least 8 weeks. The lymphocytes in the second group consisted mainly of non-granulated lymphocytes or some granulated lymphocytes with fine and indistinct granules and responded well to cyclosporine therapy. A reduction in lymphocytes mass was not a prerequisite for the development of the remission of red cell aplasia in this group, and responses occurred within 4 weeks. Clonal T cell proliferation was detected in some patients, which raised the possibility of idiopathic PRCA being associated with a clonal proliferation of T cells. Distinguishing lymphocytes in patients with PRCA could potentially be used to plan treatment strategy and assess prognosis.

Neutropenia Associated With T-Cell Large Granular Lymphocyte Leukemia: Long-Term Response to Cyclosporine Therapy Despite Persistence of Abnormal Cells

T-cell large granular lymphocyte (T-LGL) leukemia is clinically indolent, but is associated with severe neutropenia in approximately 50% of cases. The pathogenesis of the neutropenia is unclear. We report reversal of severe neutropenia associated with T-LGL leukemia in five patients treated with cyclosporine (CSA). All five had persistent neutrophil counts below 0.5 × 109/L, two had agranulocytosis, and four had recurrent infections. Increased populations of LGL were present in blood and marrow, with a T-LGL immunophenotype (CD3+CD8+CD16±CD56±CD57+) shown by multiparameter flow cytometry, and clonal T-cell receptor (TCR) gene rearrangements in two of two pretreatment blood samples studied. CSA was initiated at doses of 1 to 1.5 mg/kg orally every 12 hours, with subsequent dose adjustments based on trough serum levels. Four patients attained normal neutrophil counts with CSA alone; one required addition of low-dose granulocyte-macrophage colony-stimulating factor. Time to attainment of 1.5 × 109/L neutrophils ranged from 21 to 75 days. Attempts to taper and withdraw CSA resulted in recurrent neutropenia. Three patients have maintained normal neutrophil counts on continued CSA therapy for 2, 8, and 8.5 years. Two patients died 1.7 and 4.6 years after initiation of CSA despite normal neutrophil counts—one of metastatic melanoma and one of complications after aortofemoral bypass surgery. Despite resolution of neutropenia, increased populations of T-LGL cells have persisted in all patients during CSA therapy, as shown by morphology and flow cytometry and by the presence of clonal TCR gene rearrangements in four patients' posttreatment blood samples. We conclude that CSA is an effective therapy for neutropenia associated with T-LGL leukemia, and that resolution of neutropenia despite persistence of abnormal cells implies that CSA may inhibit T-LGL secretion of yet unidentified mediators of neutropenia.

Neutropenia Associated With T-Cell Large Granular Lymphocyte Leukemia: Long-Term Response to Cyclosporine Therapy Despite Persistence of Abnormal Cells

T-cell large granular lymphocyte (T-LGL) leukemia is clinically indolent, but is associated with severe neutropenia in approximately 50% of cases. The pathogenesis of the neutropenia is unclear. We report reversal of severe neutropenia associated with T-LGL leukemia in five patients treated with cyclosporine (CSA). All five had persistent neutrophil counts below 0.5 × 109/L, two had agranulocytosis, and four had recurrent infections. Increased populations of LGL were present in blood and marrow, with a T-LGL immunophenotype (CD3+CD8+CD16±CD56±CD57+) shown by multiparameter flow cytometry, and clonal T-cell receptor (TCR) gene rearrangements in two of two pretreatment blood samples studied. CSA was initiated at doses of 1 to 1.5 mg/kg orally every 12 hours, with subsequent dose adjustments based on trough serum levels. Four patients attained normal neutrophil counts with CSA alone; one required addition of low-dose granulocyte-macrophage colony-stimulating factor. Time to attainment of 1.5 × 109/L neutrophils ranged from 21 to 75 days. Attempts to taper and withdraw CSA resulted in recurrent neutropenia. Three patients have maintained normal neutrophil counts on continued CSA therapy for 2, 8, and 8.5 years. Two patients died 1.7 and 4.6 years after initiation of CSA despite normal neutrophil counts—one of metastatic melanoma and one of complications after aortofemoral bypass surgery. Despite resolution of neutropenia, increased populations of T-LGL cells have persisted in all patients during CSA therapy, as shown by morphology and flow cytometry and by the presence of clonal TCR gene rearrangements in four patients' posttreatment blood samples. We conclude that CSA is an effective therapy for neutropenia associated with T-LGL leukemia, and that resolution of neutropenia despite persistence of abnormal cells implies that CSA may inhibit T-LGL secretion of yet unidentified mediators of neutropenia.

Genetics, phenotype, and natural history of autosomal dominant cyclic hematopoiesis

Cyclic hematopoiesis, (CH, or cyclic neutropenia) is a rare disease manifested by transient severe neutropenia that recurs approximately every 21 days. The hematologic profile of families with the autosomal dominant form (ADCH) has not been well characterized, and it is unknown if the phenotype is distinct from the more common sporadic congenital or acquired forms of CH. We studied nine ADCH families whose children displayed typical CH blood patterns. Pedigrees confirmed dominant inheritance without evidence of heterogeneity or decreased penetrance; three pedigrees suggested new mutations. Families were Caucasian with exception of one with a Cherokee Native American founder: A wide spectrum of symptom severity, ranging from asymptomatic to life-threatening illness, was observed within families. The phenotype changed with age. Children displayed typical neutrophil cycles with symptoms of mucosal ulceration, lymphadenopathy, and infections. Adults often had fewer and milder chronic neutropenia without distinct cycles. While CH is commonly described as "benign", four children in three of the nine families died of Clostridium or E. coli colitis, documenting the need for urgent evaluation of abdominal pain. Misdiagnosis with other neutropenias was common but can be avoided by serial blood counts in index cases. Genetic counseling requires specific histories and complete blood counts in relatives at risk to assess status regardless of symptoms, especially to determine individuals with new mutations. We propose diagnostic criteria for ADCH in affected children and adults. Recombinant human granulocyte colony-stimulating factor treatment resulted in dramatic improvement of neutropenia and morbidity. The differential diagnosis from other forms of familial neutropenia is reviewed.

Solid variant of aneurysmal bone cyst in a patient with cyclic neutropenia

A 16-year-old female with cyclic neutropenia (CN) was incidentally found to have a thoracic vertebral mass during the preoperative work-up for maxillary sinus surgery. An exploratory thoracotomy revealed a very vascular tumor involving T-10 and T-11 vertebral bodies. Gross total resection of the tumor was achieved. Pathology revealed a solid variant of aneurysmal bone cyst. This is a rare benign neoplasm of bone more commonly seen in the mandible and facial bones as well as involving the small tubular bones of the hands and feet. Because of its rarity, location, and an unknown association with CN, we found this case worthwhile to publish.

Humoral immune abnormalities in T-cell large granular lymphocyte leukemia

The prevalence of humoral immune dysfunction has not been defined in a large series of patients with T-cell large granular lymphocyte leukemia (T-LGL) confirmed to be clonal by T-cell receptor analysis. Therefore we evaluated the presence of multiple autoantibodies in 27 patients with this disease. Humoral immune abnormalities included: rheumatoid factor (RF) (15/27 patients), antinuclear antibody (ANA) (13/27 patients), polyclonal hypergammaglobulinemia (15/24 patients), elevated serum immunoglobulins (17/26 patients), immune complex formation (18/25 patients), elevated beta-2 microglobulin (13/18 patients) and neutrophil-reactive IgG (18/20 patients). Disease manifestations in these patients were due to complications of cytopenia or autoimmune abnormalities. Infection was a common finding (21/27 patients) and likely reflected their neutropenia. Rheumatoid arthritis (11/27 patients), anemia (12/27 patients) and thrombocytopenia (10/27 patients) were less common but still frequently observed. This study demonstrates the presence of multiple autoantibodies in a large series of patients with documented clonal T-LGL proliferations.

Cyclic haemopoiesis at 7- or 8-day intervals

We report a patient with severe anaemia and cyclic oscillations of reticulocyte and leucocyte counts, as well as serum iron (Fe), unsaturated iron-binding capacity (UIBC), ferritin, C-reactive protein (CRP) levels and temperature, at regular intervals of 7 or 8 d. After treatment with prednisolone, anaemia was corrected and the cyclic oscillations of these parameters ceased; whereas treatment with indomethacin, recombinant granulocyte-colony stimulating factor (G-CSF) and erythropoietin (Epo) were unsuccessful.

Prototypical HTLV-I/II infection is rare in LGL leukemia

The etiology of LGL leukemia is not known; however, we recently detected HTLV-II in a patient with LGL leukemia. In this study, we found that sera from 6 of 28 patients with LGL leukemia were positive for HTLV-I/II using a whole virus ELISA; moreover, the ELISA-negative sera were near the positive cut-off value. Therefore, we performed additional studies on these sera using commercially available assays which can confirm and distinguish HTLV-I from HTLV-II infection. Serum from only one patient was confirmed positive using conventional criteria (HTLV-II+). Sera from 25 patients (89%) had indeterminate reactivity on Western blot assays. Of these, sera from 21 (84%) reacted to gag protein p24; 12 (48%) reacted with recombinant env protein p21e, and 10 (40%) reacted with both. We could not detect HTLV-I/II pol or pX gene sequences in these patients using polymerase chain reaction analyses, with the exception of the HTLV-II-infected patient described previously. These data show that most patients with LGL leukemia are not infected with prototypical HTLV-I or HTLV-II. The frequent reactivity of patient sera to HTLV-I/II gag protein p24 and to env protein p21e, however, suggests that a deleted or variant form of HTLV-I/II may be associated with LGL leukemia.

Lymphoproliferative disorder of granular lymphocytes associated with severe neutropenia. Response to granulocyte colony-stimulating factor

Lymphoproliferative disorder of granular lymphocytes (LPGL) is an indolent process that is often associated with neutropenia. Although splenectomy, corticosteroids and cytotoxic agents have all been used to treat patients with life-threatening neutropenia, there are few data supporting their effectiveness. We describe a patient with LPGL, severe neutropenia, and a life-threatening infection who had a dramatic response after treatment with granulocyte colony-stimulating factor (G-CSF). The neutrophil count increased from less than 10 cells/microliters to more than 10,000/microliters after seven doses of G-CSF. The infection promptly healed. A review of the literature indicates that 8 of 11 patients with LPGL and severe neutropenia responded to treatment with G-CSF or granulocyte-macrophage colony-stimulating factor (GM-CSF). In view of their relative lack of toxicity and rapid onset of action, the colony-stimulating factors should be considered for initial therapy in patients with LPGL and severe neutropenia. In addition, the high rate of response achieved with colony stimulating factors suggests that in many cases, a defect in myeloid maturation rather than accelerated granulocyte removal is the cause of neutropenia.

Adult-onset cyclic neutropenia responsive to cyclosporine therapy in a patient with ankylosing spondylitis

A 45-year-old female with a long history of HLA-B27-positive ankylosing spondylitis and ulcerative colitis developed cyclic neutropenia. She was hospitalized for high fever during each of three consecutive episodes of absolute neutropenia. On the third hospitalization, granulocyte-colony-stimulating factor (G-CSF), 5 micrograms/kg/day, was given by subcutaneous injection and resulted in an increase of absolute neutrophil count from 0 to 2.2 x 10(9)/liter and an associated decrease of platelet count and hemoglobin as well as severe bone and joint pain predominantly in the middle and lower back and purulent diarrhea. The back pain necessitated discontinuation of the drug. Oral cyclosporine therapy was begun, and although the neutrophil count continued to oscillate, both the peaks and the nadirs were higher than previously, and symptoms of neutropenia subsided. We conclude that cyclosporine can be an effective treatment for cyclic neutropenia associated with autoimmunity since G-CSF may cause exacerbations of autoimmune disorders.

Remission of monoclonal chronic T-cell expansion associated with severe anemia

A 49-year-old male with an 8 year history of lowered Hb level, granulocytopenia and fatigue presented in 1986 with progressive fatigue, a dramatically reduced Hb level (45 g/l) and an increased lymphocyte count (6.6 x 10(9)/l). Clinical picture and laboratory studies led to the diagnosis of chronic T lymphocytosis with expansion of CD8+ T cells expressing CD16 IgG Fc receptors (Fc gamma RIII). DNA analyzed with T-cell receptor (TcR) gamma and beta probes revealed extra rearranged bands representing a clonal expansion of T lymphocytes. These T lymphocytes expressed T-cell receptor alpha beta as evaluated by staining with monoclonal antibodies. Because of the severe progressive anemia the patient was transfused with packed red cells. He was then treated with cyclophosphamide. After one month of treatment the transfusions could be discontinued and two months later cyclophosphamide treatment was stopped because of normalized Hb level and lymphocyte counts. The patient remained in a hematologically stable condition, though a minor T-cell population representing the clonal expansion, an inverted CD4/CD8 ratio and low immunoglobulin levels persisted. This is the first report of regression of proven monoclonal CD8+ T gamma-cell expansion and the associated anemia following cyclophosphamide therapy. These observations implicate the expanded monoclonal CD8+ lymphocytes in the pathogenesis of the anemia and granulocytopenia.

Treatment of cyclic neutropenia with granulocyte colony-stimulating factor

Six patients with cyclic neutropenia were treated with recombinant human granulocyte colony-stimulating factor (G-CSF) for 3 to 15 months. All had a history of recurrent aphthous stomatitis, pharyngitis, lymphadenopathy, fever, and numerous infections during periods of neutropenia. Serial blood-cell counts, findings on bone marrow examination, and signs and symptoms were evaluated before and during the daily administration of G-CSF (3 to 10 micrograms per kilogram of body weight per day), either intravenously or subcutaneously. The kinetics of labeled autologous blood neutrophils and the migration of neutrophils to skin chambers were also measured. Recombinant human G-CSF increased the mean (+/- SEM) neutrophil counts from 717 +/- 171 per microliter to 9814 +/- 2198 per microliter (P = 0.009). In five of the six patients, the cycling of blood-cell counts continued, but the length of the period decreased from 21 to 14 days. The number of days of severe neutropenia was reduced (P = 0.002). Neutrophil turnover increased almost four-fold (P = 0.005), whereas neutrophil migration to a skin chamber was normal. G-CSF therapy reduced the frequency of oropharyngeal inflammation, fever, and infections in these patients. During the first 40 months of treatment, no typical mouth ulcers or bacterial infections occurred; recurrent gingivitis improved. We conclude that G-CSF is effective for the treatment of cyclic neutropenia in humans.

Adult-onset cyclic bicytopenia: a case report and review of treatment of cyclic hematopoiesis

A unique case of adult-onset synchronous cyclic neutropenia and thrombocytopenia occurring at six-week intervals is presented. Periods of cytopenia were associated with fever, myalgias, gastrointestinal symptoms, and mild mucocutaneous bleeding. Alternate-day steroid treatment failed to correct the periodic fluctuations in peripheral blood counts but ameliorated symptoms during cytopenia. The treatment of cyclic hematopoiesis is reviewed.

Cyclic neutropenia: a clinical review

Cyclic neutropenia is a benign, hematologic disorder characterized by recurrent episodes of severe neutropenia at 21 day intervals. There are associated cyclical variations in other blood cells. Patients with this disease have malaise, stomatitis, cervical lymphadenopathy and fever during the recurrent neutropenic periods. The exact cause of cyclic neutropenia is unknown. About one third of human cases appear to be inherited in an autosomal dominant pattern. In the other cases, the disease appears to arise spontaneously with symptoms usually beginning in infancy or early childhood. In adult patients, the disease may be acquired and occur in association with a clonal proliferation of large granular lymphocytes. Clinical studies in man and investigations in grey collie dogs, which have a very similar disease, strongly suggest that cyclic neutropenia is due to an abnormality in the regulation of early hematopoietic precursor cells. Therapy for cyclic neutropenia involves local and symptomatic therapy for the recurrent mouth ulcers and pharyngitis, and antibiotics for episodes of sinusitis, pneumonia, peritonitis, or bacteremia. Therapy with glucocorticosteroids, androgens, and plasmapheresis has been efficacious in a few adult patients, but no therapy has been proven to alter the cycling of blood counts in children. Despite their repetitive illnesses, patients with cyclic neutropenia grow and develop normally. With the help of attentive physicians and dentists, their quality of life and life expectancy are good. Current research on hematopoietic growth factors offers promise of new approaches to therapy.

Differentiation in vitro of T3+ large granular lymphocytes with characteristic cytotoxic activity from an isolated hematopoietic progenitor colony

Blast colonies were developed by rIL-3 from the spleen cells of mice pretreated with 5-fluorouracil (5-FU) in the methylcellulose cultures. When such IL-3-induced blast colonies were individually lifted up and recultured in the presence of rIL-3 and recombinant erythropoietin (rEpo), a variety of hematopoietic colonies developed from every single colony, including neutrophils, macrophages, eosinophils, megakaryocytes, mast cells, and erythroblasts. The results indicated that IL-3-induced blast colonies consisted of multipotential hematopoietic progenitor cells. By culturing individual IL-3-induced blast colonies in the presence of rIL-2 and irradiated peritoneal macrophages, on the other hand, the proliferation of homogeneous lymphoid cells was observed in 5 of 24 wells, each of which received a single blast colony. Morphologically, they were typical large granular lymphocytes (LGL), and thus it was indicated that LGL could be differentiated directly from the hematopoietic progenitor cells utterly in vitro by rIL-2 and accessory macrophages. From one of these culture wells, a continuous LGL line, IL3B1, was successfully obtained. The proliferation of IL3B1 was dependent on IL-2 in the presence of accessory macrophages, but they no longer responded to IL-3, nor to another T cell growth factor, IL-4. Flow cytometric analysis indicated that the phenotype of IL3B1 was Thy-1+,T3+,L3T4-,Lyt-2-,T200+ Asialo GM1+, whereas that of original IL-3-induced blast cells was Thy-1+,T3-,L3T4-,Lyt-2-,B220-. The results suggested that the expression of T3 molecules was induced in the process of LGL differentiation from the hematopoietic progenitor cells in vitro. Conforming to this, it was revealed that both gamma and beta chain genes of the TCR were rearranged in IL3B1. Northern blot analysis indicated that IL3B1 had abundant mRNA for gamma chain, while mRNA for beta chain was rather faint. Functionally, IL3B1 exhibited typical NK-patterned cytotoxic activity against a panel of tumor cell targets. In addition, they showed significant cytotoxic activity against normal bone marrow cells, as well as various factor-dependent myelogenous progenitor cell lines, all of which were resistant to endogenous NK activity of the fresh spleen cells. These results indicated that at least a set of T3+ LGL with rearranged TCR genes could be directly differentiated from isolated hematopoietic progenitor cells in vitro. Results also suggested that such a prethymically differentiated subset of T-lineage lymphocytes, namely T3+ double-negative LGL, had particular cytotoxic activity in addition to conventional NK activity, which might well contribute to feedback regulation of hematopoiesis.

Generation of continuous large granular lymphocyte lines by interleukin 2 from the spleen cells of mice infected with Moloney leukemia virus. Involvement of interleukin 3

Continuous cell lines could be reproducibly established by culturing spleen cells from adult mice injected with MLV-producer cells or directly infected with Mo-MLV with rIL-2, whereas the culture of normal splenic cells with rIL-2 induced only transient and limited proliferation resulting in no such lines. All of the lines showed morphological characteristics as LGL with Thy-1+,Lyt-1-,L3T4-,Lyt-2-,AsGM1+,FcR gamma+ phenotype without exception, and most of them exhibited typical NK-patterned cytotoxicity. Analysis of reverse transcriptase activity of the culture supernatants as well as Southern hybridization of the DNA from the lines using an Mo-MLV-specific cDNA probe indicated no evidence of retroviral replication or proviral integration, suggesting that the generation of cell lines reflected a reactive process and viral infection was not directly responsible. It was subsequently revealed that Thy-1+,Lyt-1+,Lyt-2- spleen cells from mice infected with Mo-MLV in vivo spontaneously produced surprising amounts of IL-3 in vitro, leading to the possibility that IL-3 was responsible for the generation of lines. The possibility was directly supported by the observation that continuous lines with identical characteristics could be generated completely in vitro by sequential stimulation with rIL-3 and rIL-2 from normal spleen cells without any involvement of Mo-MLV. The C beta gene of TCR was shown to be rearranged in all the lines examined, indicating the LGL lines were all genetically committed to T cell lineage. Unlike the situation in normal splenic populations expanded by rIL-2, where the expression of IL-2-R was progressively lost, constitutive expression of high-affinity-IL-2-R was observed in all the lines and thus, this was considered to explain the unlimited proliferation of them in response to rIL-2 alone. These results suggested the probable role of IL-3 in the regulation of growth and differentiation of a set of LGL committed to T cell lineage. The possible implications of the phenomenon in the regulation of hematopoiesis as well as in the control of Mo-MLV-induced leukemogenesis were discussed.