Combined measurement of growth and differentiation in suspension cultures of purified human CD34-positive cells enables a detailed analysis of myelopoiesis.

In this study we have made a detailed analysis of growth factor (granulocyte-macrophage colony-stimulating factor [GM-CSF], granulocyte colony-stimulating factor [G-CSF], and macrophage colony-stimulating factor [M-CSF])-induced proliferation and differentiation of highly purified CD34+ committed human myeloid progenitor cells in suspension cultures. The results were compared with colony formation in semisolid medium. Proliferation in suspension cultures was determined by means of incorporation of [3H]thymidine, differentiation by flow cytometric immunophenotyping using a panel of monoclonal antibodies against monomyeloid antigens, and by morphology. A good correlation was found between the number of granulocyte-macrophage colony-forming units (CFU-GM) in semisolid medium and [3H]thymidine incorporation in suspension (r = 0.82), both assessed at day 11. Moreover, the frequency of proliferating cells as determined in suspension cultures by limiting dilution analysis was similar to the frequencies of CFU-GM as measured in semisolid medium. Studies on GM-CSF- and G-CSF-induced cell-growth kinetics revealed distinct proliferation patterns. Immunophenotypically the subsequent induction of the mature granulocytic antigens CD15 and CD67 was observed to be accompanied by a gradual loss of the HLA-DR antigen, whereas little monocytic differentiation was observed. M-CSF, although inducing no colony formation of CD34+ cells and minimal proliferation in suspension, induced monocytic differentiation, demonstrated by the expression of HLA-DR, CD14, and CD36 in the absence of CD15 and CD67. The observed immunophenotypical profiles were confirmed by the results of cytological characterization. Thus, the combined measurement of growth factor-induced proliferation and differentiation of progenitor cells in suspension cultures can be a useful alternative for the CFU-GM assay. Moreover, because small numbers of cells are required, it allows for detailed studies on cell-growth kinetics and developmental stages within the granulocytic and monocytic lineages.

Interleukin-6 is a survival factor for committed myeloid progenitor cells.

In this study, we investigated the effect of recombinant human interleukin-6 (IL-6) on colony-forming cells for granulocytes and macrophages (CFU-GM) cultured in suspension. IL-6 when used alone did not induce proliferation of highly purified CD34+ human hematopoietic progenitors. Moreover, no influence of IL-6 was observed on the proliferation induced by granulocyte-macrophage colony-stimulating factor (GM-CSF) or granulocyte (G)-CSF. However, a marked survival enhancement (GM-CSF 228 +/- 42%, p < 0.01, and G-CSF 137 +/- 9%, p < 0.05) was observed when CD34+ cells were preincubated with IL-6 for 6 days. This survival effect became even more pronounced under serum-poor conditions (GM-CSF 380 +/- 80%, p < 0.01, and G-CSF 180 +/- 20%, p < 0.01) and could also be demonstrated at the single cell level in a colony-forming assay. By analysis of subpopulations of CD34+ bone marrow (BM) cells selected on the basis of CD45RO expression, the observed IL-6-mediated survival effect was found to be restricted to the CFU-GM containing CD45RO- subset. Our data show that IL-6 is a survival factor for CFU-GM.

Management of AIDS-related non-Hodgkin's lymphomas.

The incidence of non-Hodgkin's lymphoma in individuals infected with HIV is approximately 60- to 100-fold increased over the general population. The majority of patients with AIDS-related lymphoma (ARL) present with stage III-IV disease and with B-symptoms. They often have multiple extranodal localisations, with a high incidence of central nervous system involvement. Histologically, most tumours are either diffuse large cell lymphomas or Burkitt lymphomas. Several factors, such as disrupted immune surveillance, Epstein-Barr virus infection, chronic antigenic stimulation, cytokine dysregulation and the acquisition of genetic lesions, are thought to contribute to the pathogenesis. Patients with ARL have a poor prognosis: overall survival ranges from 1.5 to 18 months. The most important adverse prognostic factors are poor performance status, a low CD4+ cell count and a history of opportunistic infections. Results of treatment with polychemotherapy compare unfavourably to results in patients without HIV infection. Since the advent of highly active antiretroviral therapy (HAART), there appears to be a decrease in the incidence of ARL. In addition, the use of HAART in combination with chemotherapy and the use of new treatment modalities may improve the outcome of this disease.

Antigen receptor function in chronic lymphocytic leukemia B cells.

Functional studies revealed that two groups of B chronic lymphocytic leukemia (B-CLL) can be distinguished based on their capacity to mount a proliferative response following B-cell antigen receptor (BCR) cross-linking. The molecular basis for the functional distinction between these B-CLL groups most probably resides within or proximal to the BCR since non-responsive B-CLL, in marked contrast to responsive B-CLL, do not respond to BCR ligation with tyrosine phosphorylation of cellular substrates and increases in the free intracellular [Ca++]. Detailed biochemical analysis showed overall structural identity between responsive and non-responsive B-CLL with respect to both transmembrane and intracellular associates of the BCR complex. However expression levels of the protein tyrosine kinase syk, which is a key enzyme for the early signalling through the BCR, were found to be markedly lower in non-proliferating B-CLL. Here we will review current functional and biochemical data on responding and non-responding B-CLL and discuss the relevance of these findings for disease progression and our insight into the immunobiology of B-CLL.

CD27-CD70 interaction: unravelling its implication in normal and neoplastic B-cell growth.

Members of the Tumour Necrosis Factor-Receptor (TNFR) family play an essential role in the control of lymphoid cell growth and differentiation. The ligand of one of its lymphoid-specific members, CD27, was recently characterized as CD70, a type II transmembrane molecule with homology to TNF that is expressed on activated T and B cells. Ligation of CD27 by its natural ligand generates a potent costimulatory signal for cytokine production and proliferation of activated T cells. In contrast to normal B cells, where CD27 expression is confined to germinal centre cells and to a small subset of circulating B lymphocytes, CD27 expression is found on a large array of distinct B-cell neoplasia. Here, we review recent data on the expression and function of TNFR family members on normal and malignant lymphocytes and propose a role for CD27-CD70 interaction in B-cell development.

Effects of recombinant human granulocyte colony-stimulating factor on leucopenia in zidovudine-treated patients with AIDS and AIDS related complex, a phase I/II study.

Twelve male patients, eight with the acquired immunodeficiency syndrome (AIDS) and four with AIDS related complex (ARC), who had zidovudine associated neutropenia (less than 1 x 10(9) neutrophils/l) were treated with recombinant human granulocyte colony-stimulating factor (G-CSF) in a phase I/II study. Treatment consisted of daily subcutaneous injections with G-CSF in a weekly increasing dose of 0.4, 2, 5 or 10 micrograms/kg body weight until a neutrophil count of more than 3 x 10(9) neutrophils/l was observed. This effective dose was continued for up to 4 weeks, followed by 4 weeks observation period without G-CSF treatment. Two patients (both with ARC) reached target neutrophil counts at the lowest G-CSF dose, whereas nine patients needed 2 micrograms/kg. One patient discontinued treatment before he reached target neutrophil counts. Mean (+/- SD) neutrophil counts before and after 1 and 4 weeks of effective dose treatment were 0.65(+/- 0.188) x 10(9), 6.016(+/- 2.595) x 10(9) and 5.54(+/- 4.237) x 10(9)/l respectively (P less than 0.01). The number of monocytes increased from 0.171(+/- 0.113) to 0.501(+/- 0.274) and 0.474(+/- 0.374) x 10(9)/l after 1 and 4 weeks of treatment (P less than 0.01). Other haematologic parameters did not change significantly. Two weeks post-treatment the numbers of neutrophils and monocytes had returned to pre-treatment values. Mild side effects consisting of bone, joint or muscle pain were observed in three patients. Two patients (both with AIDS) did not complete the study. One patient stopped treatment because of fever and malaise, attributable to a generalized cytomegalovirus (CMV) infection and one patient had to stop zidovudine treatment because of severe thrombocytopenia. We conclude that G-CSF increases the number of circulating neutrophilic granulocytes in zidovudine-treated patients at relatively low doses and with few side-effects.

Incidence and clinical epidemiology of streptococcal septicemia during treatment of acute myeloid leukemia.

The incidence and outcome of streptococcal septicemia was analyzed in 76 consecutive patients with newly diagnosed and relapsed acute myeloid leukemia. They received 215 courses of remission induction or intensive consolidation treatment. There were 31 different episodes of streptococcal septicemia in 27 patients, making these microorganisms the most frequently encountered bacteria in blood cultures. This high incidence coincided with the introduction of selective intestinal decontamination. In 24 episodes (20 patients) there was a fast recovery, but 7 patients developed pulmonary symptoms resulting in death due to respiratory failure in 5 of them. The infections all occurred in the phase of maximum bone marrow suppression 1-3 weeks after the start of the chemotherapy. Streptococcal septicemia was not limited to patients treated with cytosine arabinoside but also occurred in patients treated with other regimens of intensive chemotherapy. In 28 episodes there were no focal signs of infection, but in half there were symptoms of treatment induced gastrointestinal toxicity. The streptococci probably invade through oral and gastrointestinal mucosa damaged by the chemotherapy. Selective decontamination may play a promoting role.

Interleukin-6 and interleukin-1 production in acute leukemia with monocytoid differentiation.

Several authors have reported the in vitro production of colony-stimulating factors (CSF) and interleukin-1 (IL-1) by the neoplastic cells from patients with acute myeloid leukemia (AML). Using a sensitive bioassay for IL-6, the capacity of the leukemic cells of 30 patients with AML to produce IL-6 was examined. IL-6 production was found to be specific for cells from patients with an AML with monocytic differentiation (12 of 15 M4 and M5 patients, 0 of 15 M1 and M2 patients). Moreover, IL-6 production was paralleled by IL-1 production. The IL-6- and IL-1-producing cells were mainly found in the more mature monocytic cell fractions, defined as CD14-positive and CD34-negative adherent cells. By limiting dilution experiments, it could be excluded that the production of IL-1 or IL-6 was due to contamination with normal monocytes.

The influence of cyclosporin A on the alternative pathways of human T cell activation in vitro.

To gain further insight into the mechanism of action of the immunosuppressant cyclosporin A (CyA), we investigated the influence of CyA on proliferative responses of human T lymphocytes, induced via different membrane molecules. As was previously shown, activation of T cells via the T cell receptor (Ti)/CD3 complex with an anti-CD3 monoclonal antibody was inhibited by CyA. Likewise, triggering of T lymphocytes via the alternative, CD2(T11)-mediated pathway of activation was strongly inhibited. In contrast, responses induced by phorbol myristate 13-acetate (PMA; 100 ng/ml) or the combination of an anti-CD28 monoclonal antibody and a suboptimal concentration of PMA (1 ng/ml) were found to be insensitive to CyA. CyA-induced inhibition of both anti-CD3- and anti-CD2-mediated proliferation could not be reversed by addition of either PMA (1 ng/ml) or anti-CD28. An increase in the intracellular free Ca2+ concentration [( Ca2+]i) is an early event observed after stimulation of T cells via CD3 or CD2, whereas stimulation with PMA and anti-CD28 does not lead to a rise in [Ca2+]i. This suggests that the inhibitory action of CyA is related to Ca2+-dependent signaling pathways. Since we observed that CyA does not interfere with anti-CD3- or anti-CD2-induced increases of [Ca2+]i, our data suggest that CyA-mediated inhibition is related to a later event in these intracellular signaling pathways.

A single dose of granulocyte-macrophage colony-stimulating factor induces systemic interleukin-8 release and neutrophil activation in healthy volunteers.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) are frequently used in the clinical management of neutropenia. These cytokines not only enhance the proliferation of myeloid precursor cells but also influence the function of mature leukocytes. In a previous study, we found that the in vivo effects of G-CSF on neutrophils differed from those in vitro. In the present study, we investigated the effects of a single dose of recombinant GM-CSF (7.5 microg/kg, subcutaneously) on neutrophils, eosinophils, and monocytes in healthy volunteers. We analyzed leukocyte kinetics, phenotypical changes, neutrophil degranulation, and systemic cytokine production. After GM-CSF injection, phenotypical changes included upregulation of CD11b on all three cell types and a decreased expression of L-selectin and Fc(gamma)RIII on neutrophils. Neutrophil degranulation was evident from the increased plasma concentrations of lactoferrin and elastase. GM-CSF induced the release of interleukin-8 (IL-8), but not of IL-6 or tumor necrosis factor alpha. In comparison to the results from our previous study with G-CSF in healthy volunteers, GM-CSF induced a stronger activation of mature neutrophils but had a much less pronounced effect on the production and maturation of neutrophil precursors. These data may help to guide the choice between the two cytokines in different clinical situations.

Comparison of CHOP chemotherapy with autologous bone marrow transplantation for slowly responding patients with aggressive non-Hodgkin's lymphoma.

BACKGROUND: High-dose chemoradiotherapy combined with autologous bone marrow transplantation can cure patients with disseminated, aggressive non-Hodgkin's lymphoma in whom first-line chemotherapy has failed. In contrast, cure is rare with second-line chemotherapy. It has been suggested that patients with slow responses to the initial phase of first-line chemotherapy are at high risk for relapse. Therefore, such patients are potential candidates for early bone marrow transplantation. METHODS: To investigate whether patients with slow responses, defined as only a partial response after three courses of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), would benefit from early transplantation, we conducted a prospective, randomized trial. The early application of high-dose chemoradiotherapy and autologous bone marrow transplantation was compared with the continuation of CHOP therapy for another five courses. Patients with complete responses after three courses of CHOP (fast responses) and patients who responded partially but still had tumor-positive marrow continued with another five courses of CHOP. The study end points were the response rate, overall survival, disease-free survival, and event-free survival. RESULTS: Of 286 patients who could be evaluated for the rapidity of their response after three courses of CHOP, 38 percent had fast responses, 47 percent had slow responses, and 15 percent had no response. Among 106 patients with slow responses who had lymphoma-negative marrow, 69 patients (65 percent) were randomized. Seventy-four percent of the CHOP group and 68 percent of the transplantation group had complete remissions (P = 0.54). At four years the rates of overall, disease-free, and event-free survival were 85, 72, and 53 percent, respectively, in the CHOP group and 56, 60, and 41 percent in the transplantation group (P > 0.10). The disease-free survival in both groups did not differ significantly from that of nonrandomized patients with fast responses (54 percent at four years). CONCLUSIONS: The early application of high-dose, marrow-ablative chemoradiotherapy with autologous bone marrow transplantation does not improve the outcome in patients with aggressive non-Hodgkin's lymphoma that responds slowly to first-line CHOP chemotherapy.

Hemolytic uremic syndrome after high dose chemotherapy with autologous stem cell support.

BACKGROUND: Chemotherapy intensification may lead to new forms of toxicity such as hemolytic uremic syndrome. METHODS: Three patients are described who developed this complication 4 to 6 months after high dose chemotherapy followed by autologous stem cell support. The literature on this subject is reviewed. RESULTS: One patient was conditioned with BEAC (carmustine, etoposide, cytosine arabinoside, and cyclophosphamide) and received autologous bone marrow. The other two underwent triple peripheral stem cell transplantation after conditioning with CTC (carboplatin, cyclophosphamide, and thiotepa). Symptoms were hypertension, microangiopathic hemolytic anemia, thrombocytopenia, and renal insufficiency. One patient had a retinal vein thrombosis. One patient died of a cardiac arrest shortly after the diagnosis was made. The remaining two achieved a partial remission: one with fresh frozen plasma without plasmapheresis and fresh frozen plasma, but improved on high dose intravenous immunoglobulin and vincristine. CONCLUSIONS: Hemolytic uremic syndrome is a serious complication of the more intensive chemotherapy made possible by stem cell support. Because of the rapidly growing indications for this approach, an increase in this type of vascular complication is expected.

Intermediate-dose melphalan (IDM) combined with G-CSF (filgrastim) is an effective and safe induction therapy for autologous stem cell transplantation in multiple myeloma.

Twenty-one previously untreated multiple myeloma (MM) patients and 10 previously treated patients with refractory or relapsed disease received two or three cycles of intermediate-dose melphalan (70 mg/m2) (IDM), administered intravenously every 6 weeks. Seven previously untreated patients received three and all other patients received two courses of IDM. The objective of the study was to reduce the toxicity of high-dose melphalan (140 mg/m2) (HDM) while maintaining its cytotoxic efficacy and secondly to ensure the possibility of collecting sufficient numbers of peripheral blood stem cells (PBSC) for transplantation. 18 (85%) previously untreated patients responded, of whom four achieved CR (18%). In addition five out of 10 previously treated patients with refractory or relapsed disease responded although bone marrow toxicity in this category was a major drawback. Toxicity was moderate, consisting of alopecia and moderate bone marrow suppression: the granulocyte count dropped below 0.5 x 10(9)/l and platelets below 25 x 10(9)/l for a median of 8 and 6 d, respectively. No serious infections occurred and the majority of patients attended the out-patient clinic. In 12/14 previously untreated patients sufficient peripheral blood CD34+ cells for harvest were present in the repopulation phase after the first IDM. In nine patients peripheral blood stem cells were collected and eight patients have undergone successful transplantation. Repeated IDM followed by filgrastim is highly effective in untreated MM and may be safely administered to reduce tumour load prior to PBSC collection. Autologous stem cells harvested after repeated IDM have a full long-term repopulating capacity.

Granulocyte colony-stimulating factor administration to healthy volunteers: analysis of the immediate activating effects on circulating neutrophils.

In four healthy volunteers, we analyzed in detail the immediate in vivo effects on circulating neutrophils of subcutaneous administration of 300 micrograms of granulocyte colony-stimulating factor (G-CSF). Neutrophil activation was assessed by measurement of degranulation. Mobilization of secretory vesicles was shown by a decrease in leukocyte alkaline phosphatase content of the circulating neutrophils. Furthermore, shortly postinjection, Fc gamma RIII was found to be upregulated from an intracellular pool that we identified by immunoelectron microscopy as secretory vesicles. Intravascular release of specific granules was shown by increased plasma levels of lactoferrin and by upregulation of the expression of CD66b and CD11b on circulating neutrophils. Moreover, measurement of fourfold elevated plasma levels of elastase, bound to its physiologic inhibitor alpha 1-antitrypsin, indicated mobilization of azurophil granules. However, no expression of CD63, a marker of azurophil granules, was observed on circulating neutrophils. G-CSF--induced mobilization of secretory vesicles and specific granules could be mimicked in whole blood cultures in vitro, in contrast to release of azurophil granules. Therefore, we postulate that the most activated neutrophils leave the circulation, as observed shortly postinjection, and undergo subsequent stimulation in the endothelial microenvironment, resulting in mobilization of azurophil granules. Our data demonstrate that G-CSF should be regarded as a potent immediate activator of neutrophils in vivo.

Elevation of cerebrospinal fluid soluble CD27 levels in patients with meningeal localization of lymphoid malignancies.

Diagnosis of meningeal localization of lymphoid malignancies by means of cytologic examination of the cerebrospinal fluid (CSF) can be difficult. Thus far no reliable CSF tumor markers have been identified. CD27 is a transmembrane disulfide-linked 55-kD homodimer present on most peripheral blood T cells and on a subset of B cells. CD27 is also expressed on human malignant B cells and high levels of soluble CD27 can be present in the serum of patients with B-cell malignancies. The aim of this study is to determine prospectively the diagnostic value of CSF sCD27 as a tumor marker in patients with meningeal localization of lymphoid malignancies. CSF sCD27 levels were determined by sandwich enzyme-linked immunosorbent assay. The optimal cut-off value using receiver operator characteristics curves was found to be 10 U/mL. sCD27 levels were normal in all 50 control patients (lumbar disc protrusion) and in 39 of 40 samples obtained from patients with either solid tumors or acute myeloid leukemia. Of 104 CSF samples from 70 children with acute lymphoblastic leukemia (ALL) or non-Hodgkin's lymphoma (NHL) undergoing routine central nervous system (CNS) staging, sCD27 was false positive and false negative in only one sample each. In 70 samples from 45 patients suspected of meningeal localization of ALL or NHL, the sCD27 test had an excellent sensitivity (100%) and specificity (82%). In 7 patients with positive CSF studied longitudinally, sCD27 levels correlated very well with remission and relapse. sCD27 levels were not nonspecifically increased by the administration of cytostatic drugs. Finally, sCD27 was also elevated in the 4 patients studied with primary central nervous system lymphoma (PCNSL). CSF sCD27 is a promising tumor marker in patients with either meningeal localization of lymphoid malignancies or PCNSL, and can be useful in the differential diagnosis of CNS involvement by either lymphoid malignancies or solid tumors.

Corynebacterium CDC group JK (Corynebacterium jeikeium) sepsis in haematological patients: a report of three cases and a systematic literature review.

We describe 3 patients with Corynebacterium jeikeium sepsis in neutropenic phase during treatment for acute myeloid leukaemia. Fever was the first symptom. All had a central venous catheter which was removed. Two patients developed subcutaneous nodules containing pus when the neutrophil count recovered; 1 had intracutaneous and pulmonary lesions. They were treated with vancomycin and recovered when the neutrophil count started to rise. A review of 80 neutropenic patients with C. jeikeium sepsis reported in the literature, together with our 3 cases indicates that risk factors for infection are the presence of a central venous catheter, being an adult male or postmenopausal female, profound and prolonged neutropenia and exposure to multiple antibiotics. Skin lesions are reported in 48% and pulmonary lesions in 36% of the patients. The overall mortality is 34% but in patients with recovery of the bone marrow only 5%. Therefore haematopoietic growth factors should be considered in neutropenic patients with C. jeikeium infection.

99mTc-CD19 monoclonal antibody is not useful for imaging of B cell non-Hodgkin's lymphoma.

In this study we investigated the applicability of 99mTc-labeled CD19 monoclonal antibody (mAb) for tumor imaging in patients with B cell non-Hodgkin's lymphoma. A 1-mg sample of murine CD19 mAb was labeled with approximately 550 MBq [99mTc]pertechnetate. The labeled mAb was administered i.v. to seven patients, four without and three with pretreatment with 10 mg unlabeled CD19 mAb. The number of circulating B cells was decreased by 44 +/- 5% 1 h after injection of the radiolabeled mAb. Peripheral B cells were coated with CD19, resulting in partial modulation of CD19, most pronounced in the three pretreated patients. Whole-body images were obtained with a gamma camera and compared with results obtained by conventional imaging techniques. Initially, blood-pool activity dominated, whereas 24 h after injection the radioactivity was mainly located in the spleen, kidneys and liver. In two patients, a lesion in the spleen appeared as an unlabeled spot. In one patient, a lesion in the femur, which was detected by computed tomography (CT) and gallium-67 scans, was also seen on the CD19 scan from 1 h after administration of the radioimmunoconjugate onwards. Good imaging of bone marrow infiltration was observed in one of three patients. Lymph node involvement was not observed in any of the patients in whom affected lymph nodes were detected by CT or gallium-67 scan. In conclusion, in the present study radioimmunodetection with 99mTc-labeled CD19 mAb was found to be inferior to CT and gallium-67 scanning in the diagnosis of patients with B cell non-Hodgkin's lymphoma.

Effect of locally applied GM-CSF on oral mucositis after stem cell transplantation: a prospective placebo-controlled double-blind study.

Oral mucositis is a frequent side effect of myeloablative chemo- and radiotherapy preceding stem cell transplantation. It causes pain, poor food intake, and is a port of entry for infection. We studied whether GM-CSF applied topically in the oral cavity can prevent or ameliorate this mucositis. In 36 consecutive patients undergoing a stem cell transplantation, we performed a double-blind placebo-controlled study of 300 micrograms GM-CSF in a 2% methylcellulose gel daily versus a 2% methylcellulose gel alone. Both were locally applied in the oral cavity. The primary end-point was mucositis as measured by the WHO toxicity scale for mucositis, oral assessment scale, and a subjective pain scale, all scored daily. The secondary end-points were need to give parenteral nutrition and morphine, incidence of fever and infections, and duration of neutropenia and hospitalization. No differences were found in the median subjective pain scores, WHO scores, and oral assessment scores between the placebo and the GM-CSF groups. In both groups, nine patients required morphine for pain control. Ten patients in the placebo group and 11 in the GM-CSF group received parenteral nutrition. Documented infections, use of broad-spectrum antibiotics, and number of days with fever were similar in the placebo and the GM-CSF groups. The duration of neutropenia below 0.5 x 10(9)/l (median 14.5 days in the placebo group versus 17 days in the GM-CSF group) and the duration of hospitalization (28.5 versus 29 days) was also not significantly different. We found no beneficial effect of 300 micrograms GM-CSF dissolved in a 2% methylcellulose gel applied locally for chemo- and radiotherapy-induced mucositis in patients undergoing a stem cell transplantation.

Proliferation of T gamma cells with killer-cell activity in two patients with neutropenia and recurrent infections.

Two patients with severe granulocytopenia and recurrent infections of the skin and oropharynx had excess T lymphocytes with receptors for the Fc portion of IgG (T gamma cells) in blood and bone marrow. The abnormal T gamma cells killed antibody-sensitized target cells in vitro (killer-cell activity) but did not suppress immunoglobulin production by B lymphocytes (suppressor-cell activity). T gamma lymphocytes from normal persons showed both killer-cell activity and suppressor-cell activity. In the serum of one patient, granulocyte antibodies, possibly of an autoimmune nature, were detected. The clinical picture in conjunction with the hematologic and immunologic findings characterized the disease of both patients as a distinct entity among the chronic lymphoproliferative diseases of T-cell origin.

Recombinant granulocyte colony-stimulating factor administration to healthy volunteers: induction of immunophenotypically and functionally altered neutrophils via an effect on myeloid progenitor cells.

We performed a detailed kinetic study on the in vivo effect of a single subcutaneous dose of granulocyte colony-stimulating factor (G-CSF; 300 micrograms) in four healthy individuals on the expression and function of neutrophil Fc gamma receptors (Fc gamma R). G-CSF did not induce Fc gamma RI (CD64) on circulating neutrophils. However, neutrophils newly formed in response to G-CSF were Fc gamma RI positive and were able to perform antibody-dependent cellular cytotoxicity in an Fc gamma RI-dependent way. Fc gamma RII (CD32) expression was not changed significantly. Fc gamma RIII (CD16, phosphatidylinositol-linked) expression, slightly increased immediately (30 minutes) postinjection, was found to be strongly decreased on the newly formed population. For comparison, we studied the expression of the PI-linked proteins leukocyte alkaline phosphatase (LAP) and CD14. Intracellular levels of LAP mirrored the biphasic expression pattern as membrane-bound Fc gamma RIII. In contrast, CD14 expression on neutrophils was initially constant, followed by high levels on the newly formed neutrophils. Soluble CD14 levels were found to be elevated transiently, whereas peak levels of soluble Fc gamma III were observed as late as 6 days postinjection. In conclusion, we have shown that G-CSF results in an immunophenotypically and functionally altered neutrophil population for an important part as a result of its effect on myeloid precursor cells.