That dog won't fit: body size awareness in dogs.

With very few exceptions, no coherent model of representing the self exists for nonhuman species. According to our hypothesis, understanding of the Self as an object' can also be found in a wide range of animals including the dog, a fast-moving terrestrial predator/scavenger, with highly developed senses and complex cognitive capacity. We tested companion dogs in three experiments in which they faced three different variations of the same physical challenge: passing through an opening in a wall. We predicted that if dogs are capable of representing their own body size, they will react differently when faced with adequate or too small openings. We found that dogs started to move towards and approached the too small openings with significantly longer latencies than the suitable ones; and upon reaching it, they did not try to get through the too small openings. In another experiment, the medium-size (still large enough) opening was approached with latencies that fell between the latencies measured in the cases of the very large or the too small openings. Having discussed the potential underlying mechanisms, we concluded that our results convincingly assume that dogs can represent their own body size in novel contexts.

DNA immunization with HIV early genes in HIV type 1-infected patients on highly active antiretroviral therapy.

The aim of this study was to evaluate the immunological responses induced by DNA plasmids containing HIV regulatory genes administered in combination in HIV-1-infected patients with pretreatment with highly active antiretroviral treatment (HAART). The study is a double-blind, randomized, and placebo-controlled study, including 15 asymptomatic HIV-1-infected patients on stable HAART for at least 6 months and with plasma HIV RNA levels below 50 copies/ml. Ten patients received a combination of rev, tat, and nef intramuscularly (im) at weeks 0, 4, and 16 at increasing doses giving totals of 300 (100 x 3), 900 (300 x 3), and 1800 (600 x 3) micrograms DNA. Five patients received saline in the same amounts im. Antigen-specific cytotoxic T lymphocyte (CTL) levels were preserved or increased and new T lymphocyte proliferative responses were induced in the group immunized with the HIV DNA genes. No increase in antibody levels was noted. Despite a 10-fold higher vaccine dose, patients on HAART did not respond better to vaccination compared to non-HAART patients included in a previous study where the genes were administered separately. Combining the regulatory genes rev, tat, and nef in increasing doses may reduce the anticipated augmentation of HIV-specific T cell proliferative and CTL responses. Viral suppression did not seem to further improve the initial vaccine responses of patients with comparable CD4 levels.

Increases in circulating levels of monocyte-platelet and neutrophil-platelet complexes following hip arthroplasty.

Platelets and leucocytes are important effector cells of the haemostatic and inflammatory responses to tissue injury. To investigate the effects of surgical trauma on platelet activation (assessed by measuring levels of P-selectin and beta-thromboglobulin), leucocyte activation (CD11b expression) and leucocyte-platelet interactions (leucocyte-platelet complexes), 30 patients undergoing primary hip arthroplasty were studied before and at the end of surgery, and on days 1 and 10 post-operatively, using a whole-blood flow cytometry assay. The inflammatory response was followed by measurement of the levels of C-reactive protein and interleukin-6 in plasma, and the activation of coagulation was monitored by determination of prothrombin fragment 1+2 levels. On day 1 post-operatively a significantly increased expression of CD11b on monocytes was noted, but no direct correlation was found between monocyte activation and interleukin-6 production or C-reactive protein at this time point. The percentage of monocyte-platelet and neutrophil-platelet complexes was markedly increased on day 10 post-operatively compared with pre-operative levels, and levels of these complexes were significantly positively correlated with beta-thromboglobulin levels. Activation of coagulation (prothrombin fragment 1+2) on day 10 post-operatively was positively correlated with the extent of surgical trauma (duration of surgery, amount of blood loss) and with the increase in platelet activation (beta-thromboglobulin). In conclusion, hip arthroplasty induces platelet and coagulation activation, and also an inflammatory response that is maintained for more than 10 days post-operatively. This indicates an interaction between the immune and the haemostatic systems in the post-operative phase after hip arthroplasty.

Inhibition of activated/memory (CD45RO(+)) T cells by oxidative stress associated with block of NF-kappaB activation.

Impaired immune responses in cancer patients have been associated with oxidative stress. Increased levels of reactive oxygen species released from activated, tumor-infiltrating macrophages or granulocytes may therefore constitute a hurdle for effective immunotherapy against cancer. In this study, we investigated functional consequences and molecular events in T cells exposed to low levels of oxidative stress. We observed that cytokine production of human PBMC, upon stimulation with an HLA-A*0201-restricted influenza peptide and nonspecific receptor cross-linking, was reduced after exposure to micromolar levels of H2O2. Functional impairment as measured by IFN-gamma release occurred earlier and at lower doses of exogenously added H2O2 than required to induce apoptosis. This suggests that there is a dose window of oxidative stress leading to T cell unresponsiveness in the absence of apoptosis. The reduction of Th1 cytokines, induced by H2O2, was predominantly observed in memory/effector (CD45RO(+)) T cells and correlated with a block in NF-kappaB activation. IL-10 production was more profoundly influenced by low doses of H2O2 than IFN-gamma, TNF-alpha, and IL-2. The influence of H2O2 on production of IL-10 was not significantly different between memory/activated and naive T cells. These observations suggest that Th1 and Th2 cytokines are differently regulated under conditions of oxidative stress. Taken together, these findings may explain why Ag-experienced, CD45RO(+), T cells found in the tumor milieu are functionally suppressed.

Clinical and immunological benefits from highly active antiretroviral therapy in spite of limited viral load reduction in HIV type 1 infection.

Both naive and memory T lymphocyte responses are lost during advanced HIV infection. Treatment with highly active antiretroviral therapy (HAART) is associated with an increase in T lymphocytes and a reduction in viral load. However, the viral response to HAART in patients with low levels of helper T lymphocytes and a high viral load is often not satisfactory. We investigated the capacity of long-term HAART to reconstitute the immune system in severely ill patients. A nonselected longitudinal patient population with high baseline viral levels and CD4(+) cells below 100 x 10(6)/liter were monitored for 2 years during HAART. Markers to estimate the therapeutic effects included viral levels and cell surface markers representing naive and memory T lymphocytes as well as activation markers, B cells, NK cells, and clinical events. After 2 years of treatment, viral load was reduced to undetectable levels in 55% (viral responders, vRs) and less than 1 log (median value) from baseline in 45% (viral low responders, vLRs). Elevated numbers of memory and naive CD4(+) and CD8(+) cells as well as a decrease in activation markers were seen in both vRs and vLRs. However, the magnitude was greater in vRs. No differences in the clinical outcome were observed between vRs and vLRs. We conclude that most patients, even in advanced stages of HIV disease, benefited from HAART. The magnitude of the response was related to good viral reduction, but even patients with poor viral reduction had a recovery of naive and memory CD4(+) and CD8(+) cells. Even a small reduction in viral load is thus of importance for health and potentially also for years of survival.

Variability in B-cell antigen expression: implications for the treatment of B-cell lymphomas and leukemias with monoclonal antibodies.

OBJECTIVES: Antigen expression intensity is becoming important for decision-making in relation to monoclonal antibody therapy. By quantifying CD20, CD22 and CD52 expression on chronic lymphocytic leukemia and normal (control) B cells, over time. The effect of Interleukin-4 therapy on CD20 antigen intensity on B-CLL cells in vivo was also determined. METHODS: Lymphocytes were purified at weeks 0, 4 and 8 from five B-CLL patients, five healthy volunteers and seven B-CLL patients receiving IL-4 therapy. The number of antigen receptor sites was calculated in molecules of equivalent soluble fluorochrome using flow cytometry. RESULTS: The mean number of CD20 receptors at baseline was significantly lower on B-CLL cells compared to normal B cells (8160 vs 87 046; P<0.0001). Similar results were obtained for CD22 (8630 vs 27 647; P<0.01), but not for CD52 (371 303 vs 409 484; P = 0.54). When soluble fluorochrome values at weeks 4 and 8 were analysed as change in per cent from baseline (delta%), there was <10 delta% variability in CD20 expression on control B cells, but considerable variability (22.5-67.5 delta%) on B-CLL cells. Expression of CD22 in CLL and control B cells varied by <15 delta%. CD52 on CLL B cells showed slightly greater variability (+/-35 delta%) than that of CD22 (+/-15delta%), but less than that of CD20. IL-4 therapy did not consistently increase the CD20 expression on B-CLL cells in vivo. CONCLUSION: Our data confirm differences in intensity between different target antigens on B-CLL cells, and draws attention to the fact that a substantial variability may occur over time, which may influence clinical decision-making. Caution must be taken when interpreting in vitro results on cytokine-mediated receptor intensity up-regulation.

Immunological changes in human skeletal muscle and blood after eccentric exercise and multiple biopsies.

1. A role of the immune system in muscular adaptation to physical exercise has been suggested but data from controlled human studies are scarce. The present study investigated immunological events in human blood and skeletal muscle by immunohistochemistry and flow cytometry after eccentric cycling exercise and multiple biopsies. 2. Immunohistochemical detection of neutrophil- (CD11b, CD15), macrophage- (CD163), satellite cell- (CD56) and IL-1beta-specific antigens increased similarly in human skeletal muscle after eccentric cycling exercise together with multiple muscle biopsies, or multiple biopsies only. 3. Changes in immunological variables in blood and muscle were related, and monocytes and natural killer (NK) cells appeared to have governing functions over immunological events in human skeletal muscle. 4. Delayed onset muscle soreness, serum creatine kinase activity and C-reactive protein concentration were not related to leukocyte infiltration in human skeletal muscle. 5. Eccentric cycling and/or muscle biopsies did not result in T cell infiltration in human skeletal muscle. Modes of stress other than eccentric cycling should therefore be evaluated as a myositis model in human. 6. Based on results from the present study, and in the light of previously published data, it appears plausible that muscular adaptation to physical exercise occurs without preceding muscle inflammation. Nevertheless, leukocytes seem important for repair, regeneration and adaptation of human skeletal muscle.

Cytofluorometric methods for assessing absolute numbers of cell subsets in blood. European Working Group on Clinical Cell Analysis.

The enumeration of absolute levels of cells and their subsets in clinical samples is of primary importance in human immunodeficiency virus (HIV)+ individuals (CD4+ T- lymphocyte enumeration), in patients who are candidates for autotransplantation (CD34+ hematopoietic progenitor cells), and in evaluating leukoreduced blood products (residual white blood cells). These measurements share a number of technical options, namely, single- or multiple-color cell staining and logical gating strategies. These can be accomplished using single- or dual-platform counting technologies employing cytometric methods. Dual-platform counting technologies couple the percentage of positive cell subsets obtained by cytometry and the absolute cell count obtained by automated hematology analyzers to derive the absolute value of such subsets. Despite having many conceptual and technical limitations, this approach is traditionally considered as the reference method for absolute cell count enumeration. As a result, the development of single-platform technologies has recently attracted attention with several different technical approaches now being readily available. These single-platform approaches have less sources of variability. A number of reports clearly demonstrate that they provide better coefficients of variation (CVs) in multicenter studies and a lower chance to generate aberrant results. These methods are therefore candidates for the new gold standard for absolute cell assessments. The currently available technical options are discussed in this review together with the results of some cross-comparative studies. Each analytical system has its own specific requirements as far as the dispensing precision steps are concerned. The importance of precision reverse pipetting is emphasized. Issues still under development include the establishment of the critical error ranges, which are different in each test setting, and the applicability of simplified low-cost techniques to be used in countries with limited resources.

Subsets of T-cells and in vitro cytokine production after measles and varicellae-zoster virus antigen stimulation in allogeneic BMT patients.

This study was performed to analyse differences in T-cell proliferation induced by a latent virus, varicellae-zoster virus (VZV) and a non-latent virus, measles virus, in patients after allogeneic bone marrow transplantation (BMT). The lymphoproliferative response to measles antigen, VZV-antigen (VZV-ag), and phytohemagglutinin (PHA) was measured by 3H-thymidine incorporation, and interferon-gamma (IFN-gamma) and interleukin-10 (IL-10) analyses in supernatants after in vitro stimulation of peripheral blood mononuclear cells (PBMC) from 22 patients and 18 healthy controls. The cytokine levels were correlated with T-cell subsets by FACS analyses. At the antigen concentrations used, VZV-ag induced higher levels of IFN-gamma (p < 0.05) than did the measles antigen, whereas the levels of IL-10 were similar. Patients without a cell mediated immune (CMI) response to VZV-ag or measles antigen had lower CD4+ T-cell counts than did controls (p < 0.01 in both cases) and lower IFN-gamma production after non-specific PHA stimulation (p <0.01). The IFN-gamma and IL-10 levels after measles antigen stimulation correlated with the number of CD4+ T-cells (p < 0.01 and p < 0.05, respectively), and after VZV-ag mainly to the number of CD8+ T-cells (p < 0.01 and p < 0.05, respectively). These results suggest that there is a difference in the types of T-cells that respond to VZV-ag and measles antigen stimulation, respectively. The impaired CMI response to viral antigens seen in many patients may be explained both by a low number of CD4+ T-cells and by a cell dysfunction.

Effects of eccentric exercise on the immune system in men.

The effects of eccentric exercise on changes in numbers of circulating leukocytes, cell activation, cell adhesion, and cellular memory function were investigated in 12 men, aged 22-35 yr. The immunologic effects of postexercise epidermal treatment with monochromatic, infrared light were also evaluated. Blood was drawn before and 6, 24, and 48 h after exercise for phenotyping and analysis of creatine kinase activity. There was an increase in leukocyte, monocyte, and neutrophil number, no change in the number of basophils, eosinophils, B cells, and T cells, and a decrease in natural killer cell number postexercise. Some markers of lymphocyte and monocyte activation remained unchanged or decreased, whereas the expression of adhesion molecules 62L and 11b increased on monocytes. It is concluded that eccentric exercise induced decreased activation, and increased cell adhesion capacity, of monocytes. Altered trafficking of cells between lymphoid tissue and blood, selective apoptosis, or attachment/detachment from the endothelial wall can explain the observed phenotypic changes. Treatment with monochromatic, infrared light did not significantly affect any of the investigated variables. Correlations between immunologic and physiological parameters indicate a role of the immune system in adaptation to physical exercise.

Indicators of T-cell activation: correlation between quantitative CD38 expression and soluble CD8 levels in asymptomatic HIV+ individuals and healthy controls.

Increased activation of CD8+ T cells, particularly increased expression of CD38 antigen, has been shown to strongly correlate with progression of human immunodeficiency virus-positive (HIV+) individuals to acquired immunodeficiency syndrome (AIDS) and death. As part of a study evaluating responses to a recombinant gp160 vaccine, we have used quantitative three-color flow cytometry (QFCM) to further investigate the relationships among several measures of lymphocyte activation/immunological status. Parameters evaluated included 1) absolute circulating counts for the major lymphocyte phenotypes (T, B, NK) and selected activated/regulatory subsets believed to have clinical value in the monitoring of patients with HIV infection; 2) level of CD38 expression (antibody-binding capacity [ABC]) on the lymphocyte subsets defined by CD8, CD38, and HLA-DR; and 3) serum levels of soluble CD8. CD8+DR+CD38+ counts were found to be markedly increased (approximately 10-fold) in HIV+ individuals, whereas CD4+CD45RA+ counts were markedly decreased (approximately 5-fold). We confirmed previous reports that CD38 expression on CD8 T cells (here reported as CD38 ABC) are increased in asymptomatic HIV+ individuals as compared with healthy controls, and further found that CD38 ABC was elevated approximately 2-fold on CD8+DR+ cells as compared with CD8+DR- cells in healthy controls, and almost 2-fold further elevated on CD8+DR+ cells in HIV+ individuals compared with CD8+DR+ cells in healthy controls. In agreement with previous studies, we found increased serum CD8 levels (sCD8) and increased CD8+DR+ counts in asymptomatic HIV+ individuals. However, when sCD8 was expressed relative to CD8+DR+ cell counts (RsCD8), this index was found to be significantly decreased in HIV+ individuals. Although CD38 ABC on CD8+DR+ cells showed no correlation with sCD8, it was significantly correlated with RsCD8 in both HIV+ and HIV- individuals. Absolute lymphocyte counts were strongly correlated with both CD38 ABC and RsCD8 in HIV+ individuals. However, CD4 counts were correlated with CD38 ABC (but not RsCD8) in HIV+ patients and with RsCD8 (but not CD38 ABC) in HIV-controls. Our results suggest that QFCM is significant in understanding the role of CD8+DR+CD38+ cells in processes such as lymphocyte homeostasis and HIV-induced CD4-cell depletion.

Flow cytometric quantitation of immunofluorescence intensity: problems and perspectives. European Working Group on Clinical Cell Analysis.

Quantitation of immunofluorescence intensity serves to estimate the number of defined molecules expressed on or in cells. Clinical applications of this diagnostic tool are increasing, e.g., aberrant expression of various antigens (Ag) by leukemic blasts or lymphoma cells, intensity of CD38 expression by CD8+ T-lymphocytes to monitor activation status, and intensity of CD62P to detect platelet activation. In this report we discuss the quality-control measures required for quantitation of fluorescence intensity, and we review seven concepts that have been developed to quantify fluorescence intensity during the past 15 years. Initial work addressed the conversion of logarithmic channel numbers into units of relative fluorescence. The design and use of calibration beads labeled with predefined amounts of dye allowed instrument-independent expression of fluorescence intensity in units of molecules of equivalent soluble fluorochrome (MESF). This method was refined by the combined use of such standards with monoclonal antibodies (mAb) conjugated 1:1 with phycoerythrin (PE), allowing translation of fluorescence intensity into numbers of antibodies bound per cell. Alternatively, the use of 1:1 PE-conjugated mAb under the assumption that CD4+ lymphocytes reproducibly bind 50,000 CD4 mAb molecules was proposed to convert units of relative fluorescence intensity into units of antibodies bound per cell. The use of antibody-binding capacity as a surrogate marker for quantification of Ag expression was addressed more directly by the development of antibody-binding standards. The quantitative indirect immunofluorescence assay is based on beads labeled with various amounts of CD5 mAb that calibrate the binding of the secondary antibody in units of antibody-binding capacity. Alternatively, goat anti-mouse-labeled calibration beads have been developed. Published results obtained with the latter calibrators showed an unexpected inaccuracy. The different ways in which calibrators and cells under study bind mAb (i.e., Fab mediated versus Fc mediated) may have contributed to this variation. Recently, the use of stabilized cell populations expressing Ag in a specified range of concentrations has been proposed as an Ag-specific calibration system of mAb binding. We identify several issues on the level of instrumentation, reagents, and cells under study that should be solved to allow standardization of quantitative assessments of immunofluorescence intensity.

Performance of calibration standards for antigen quantitation with flow cytometry.

In the frame of the activities initiated by the Task Force for Antigen Quantitation of the European Working Group on Clinical Cell Analysis (EWGCCA), an experiment was conducted to evaluate microbead standards used for quantitative flow cytometry (QFCM). An unified window of analysis (UWA) was established on three different instruments (EPICS XL [Coulter Corporation, Miami, FL], FACScan and FACS Calibur [Becton Dickinson, San Jose, CA]) with QC3 microbeads (FCSC, PR). By using this defined fluorescence intensity scale, the performance of several monoclonal antibodies directed to CD3, CD4, and CD8 (conjugated and unconjugated), from three manufacturers (BDIS, Coulter [Immunotech], and DAKO) was tested. In addition, the QIFI system (DAKO) and QuantiBRITE (BDIS), and a method of relative fluorescence intensity (RFI, method of Giorgi), were compared. mAbs reacting with three more antigens, CD16, CD19, and CD38 were tested on the FACScan instrument. Quantitation was carried out using a single batch of cryopreserved peripheral blood leukocytes, and all tests were performed as single color analyses. Significant correlations were observed between the antibody-binding capacity (ABC) values of the same CD antigen measured with various calibrators and with antibodies differing in respect to vendor, labeling and possible epitope recognition. Despite the significant correlations, the ABC values of most monoclonal antibodies differed by 20-40% when determined by the different fluorochrome conjugates and different calibrators. The results of this study indicate that, at the present stage of QFCM consistent ABC values may be attained between laboratories provided that a specific calibration system is used including specific calibrators, reagents, and protocols.

Decreased expression of signal-transducing CD3 zeta chains in T cells from the joints and peripheral blood of rheumatoid arthritis patients.

Although T cells from patients with rheumatoid arthritis (RA) have previously been determined to have poor proliferative responses to a variety of stimuli, the underlying mechanism is not known. We have investigated the expression of the signal-transducing zeta molecule in subsets of T cells and natural killer (NK) cells derived from the peripheral blood mononuclear cells (PBMC) and synovial fluid mononuclear cells (SFMC) of RA patients using quantitative flow cytometry, Western blot analysis and immunohistochemistry. A decrease of zeta expression was apparent in all investigated lymphocyte subsets from the PBMC and SFMC of RA patients, as compared to the corresponding subsets from healthy age- and sex-matched controls. A less pronounced reduction of cell surface-located CD3 epsilon, CD4 and CD8 was also located in T cells from SFMC as compared to PBMC from RA patients. Biochemical demonstration of the low or absent CD3 zeta in PBMC from patients with RA was achieved by Western blot analysis. Immunohistochemical staining and image analysis also confirmed the low expression of zeta chains in synovial tissue of RA patients. The possibility that the decreased expression of zeta and of immune functions of T cells from RA patients may be related to the presence of free oxygen radicals, as we have previously reported in cancer patients, should be considered.

High correlations of anti-CMV titers with lymphocyte activation status and CD57 antibody-binding capacity as estimated with three-color, quantitative flow cytometry in blood donors.

Blood samples of 58 blood donors (ages 19-64 years, 31 males and 27 females) were investigated with three-color, quantitative flow cytometry. IgG anti-cytomegalovirus (CMV) was estimated with ELISA. Nineteen men and 21 women were found CMV-seropositive. The seropositive individuals (CMV-pos) compared to the seronegative ones (CMV-neg) presented no significant changes in the absolute number of lymphocytes or in the main lymphocyte subpopulations identified by CD20, CD3, CD4, and CD8. Nevertheless, CMV-pos showed significantly higher numbers of lymphocytes with the following phenotypes: CD4+HLA-DR+, CD8+HLA-DR+, CD8+CD45RA+ CD45RO+, and CD20+CD5+. The CD3+CD57+ subset of T lymphocytes was also significantly higher in CMV-pos (P < 0.0001), whereas the CD57+CD16 & CD56+CD3- NKC subset presented similar values in both groups. Higher values for the antibody-binding capacity of lymphocytes CD38 (P < 0.05) and CD45 (P = 0.02) antigens and of CD57 antigen on CD3+ lymphocytes (P < 0.0005) were found in the CMV-pos group. These results show that CMV upregulates the number of CD57 molecules on CD3+ and not on CD3- lymphocytes and suggest that the CD3 molecule or other molecules specifically present in T cells can play a role in CMV latency. The study also showed that CMV plays a major role in the maintenance of a fraction of lymphocyte in the activated state.

Alterations in the signal-transducing molecules of T cells and NK cells in colorectal tumor-infiltrating, gut mucosal and peripheral lymphocytes: correlation with the stage of the disease.

T cells from mice bearing an experimental colon carcinoma, and from patients with colorectal and renal carcinomas, have atypical T-cell receptors (TCR). In the present study, further characterization of modulations in CD3- and CD16-associated zeta chain in peripheral blood lymphocytes (PBL) and tumor-infiltrating lymphocytes (TIL) from colorectal carcinomas was performed. Relative to PBL, the percentage of natural killer (NK) cells among fresh TIL was reduced, while a higher proportion of T cells expressing HLA-DR was found. As previously reported, we found significantly reduced levels of the CD3- and CD16-associated zeta chain in TIL and, to a lesser extent, also in patients' PBL. Levels of zeta chain in T and NK cells from non-cancerous colorectal tissue from patients were lower than in PBL but higher than in TIL, with a direct relationship between levels of this signal-transducing molecule and the distance from the tumor. In addition, zeta levels correlated with the Dukes' stage of the disease, since PBL from patients with lymph-node involvement or distant organ metastases (Dukes' stages C and D) had significantly less CD3 zeta than patients with localized disease (stages A and B). Patients' T cells also had decreased levels of cell-surface and cytoplasmic CD3 epsilon. We also observed reduced levels of the TCR accessory molecules CD4 and CD8, mainly on TIL but to a lesser extent also on patients' PBL. Biochemical analysis of anti-CD3 epsilon-immunoprecipitated TCR complexes demonstrated that the CD3 complex was not associated with the zeta chain, either on TIL or on PBL or on lymphocytes from non-cancerous colon tissue, suggesting a defect in the assembly of the TCR complex. Following several days of in vitro culture with recombinant interleukin-2 and phytohemagglutinin, anti-CD3 or anti-CD2 monoclonal antibodies (MAbs), levels of CD3 zeta chain as well as of cell surface CD3 epsilon were normalized. Our findings suggest an abnormal expression as well as assembly of several different signal-transducing molecules of T cells and NK cells, which correlate with the stage of the disease in patients with colorectal carcinomas.

Determination of the antibody binding capacity of lymphocyte membrane antigens by flow cytometry in 58 blood donors.

The relative density of lymphocyte CD3, CD4, CD5, CD8, CD20, CD23, CD28, CD38, CD45RA, CD45RO, CD57 and HLA-DR antigens was measured as antibody binding capacity (ABC) in 58 blood donors aged 19-66 years. The group was analysed in order to obtain reference values (percentages and absolute numbers) for routine, quantitative three-colour flow cytometry (FC) tests, and we included around ten males and females for each of the 15 year age intervals. Whole blood was stained (30 min on ice) with FITC, PE or PerCP conjugated MAbs. The analysis was performed with a FACScan equipped with LYSYS II and Paint-a-GatePlus software. The instrument was calibrated daily with QC3, QuickCal (FITC and PE) and Calibrite and monthly with QSC and stained cells (which included also the control for PerCP performance). The ABC was measured with QSC (Flow Cytometry Standards Corporation). The CD4+ lymphocytes expressed significantly more CD3, CD28 and HLA-DR antigens, and less CD45RA antigen than the CD8+ cells (p < 0.0001). A significant decrease with age was observed for CD3 and CD45RA on both CD4+ and CD8+ subsets (p < 0.05). The lymphocytes of women, compared with those of men, showed decreased ABC for CD8, CD20 and CD28 antigens. The results illustrate the necessity for close matching of control with case groups. They also illustrate the possibilities of modern FC methods based on quantitative quality control and three-colour analysis.

Neutropenic fever following cladribine therapy for symptomatic hairy-cell leukemia: predictive factors and effects of granulocyte-macrophage colony-stimulating factor.

BACKGROUND: Neutropenic fever is the commonest complication of cladribine therapy for hairy-cell leukemia (HCL), leading to a 3% mortality rate. Our aim was to identify predictive factors and evaluate the effects of concomitant granulocyte-macrophage colony-stimulating factor (GM-CSF). PATIENTS AND METHODS: We studied 102 patients with active HCL given cladribine for 7 days. Pretreatment parameters predicting neutropenic fever were analysed. Twelve patients at high risk for febrile complications also received 400 micrograms GM-CSF per day on days 1 through 21. RESULTS: Pretreatment anemia, hypocholesterolemia, bone marrow differential with a high percentage of hairy cells and a low percentage of myelopoietic cells, low albumin, and high C-reactive protein predicted neutropenic fever. The addition of GM-CSF did not improve the kinetics of recovery for neutrophils, hemoglobin or platelets, as compared to matched control patients. However, GM-CSF significantly reduced cladribine-induced lymphopenia, but not the incidence of neutropenic fever. CONCLUSION: Factors predicting febrile neutropenia were identified. GM-CSF protected from cladribine lymphotoxicity but did not improve neutropenia or febrile episodes.

Low-dose cladribine for symptomatic hairy cell leukaemia.

Cladribine is an effective therapy for hairy cell leukaemia (HCL), but the standard regime is frequently complicated by neutropenic fever and prolonged T-cell depression. We studied 102 patients with active HCL following treatment with various doses of cladribine given for 7 d. Two patients received 1 mg cladribine/m2/d without toxicity or effect. Eight subsequent patients received 2 mg cladribine/m2/d, and normalized cytopenia as quickly as 94 control patients receiving a standard dose (3.4 mg/m2 or 0.085 mg/kg), with significantly less lymphopenia and a similar complete remission rate.

Flow cytometry of blood and bone marrow cells from patients with hairy cell leukemia: phenotype of hairy cells and lymphocyte subsets after treatment with 2-chlorodeoxyadenosine.

By flow cytometry and an extensive set of markers, we characterized leukemic cells from the blood and bone marrow of 68 symptomatic patients with hairy cell leukemia (HCL). Hairy cells identified in the large cell gate always expressed CD19, CD20, HLA-DR, CD45RA, and B-ly 7. Other markers were occasionally expressed, such as CD38, CD45RO, CD23, CD15, CD4, CD5, and CD10 (expressed on more than 20% of the hairy cells in 44%, 25%, 21%, 18%, 12%, 10%, and 5% of evaluated cases, respectively). During treatment with 2-chlorodeoxyadenosine (CdA), the median lymphocyte counts decreased from 2,000/microL to 300/microL. Flow cytometry was repeated at the nadir (n = 24) of lymphocyte counts, at 3 months (n = 46), at 6 months (n = 50), at 1 year (n = 39), and at 2 years (n = 12) after treatment. The initial decrease of CD8+ and CD20+ cells was greater than that of CD4+ and natural killer (NK) cells, leading to an increasing CD4/CD8 ratio. Median nadir values of CD4+, CD8+, CD20+, and NK cells were 128/microL, 78/microL, 10/microL, and 13/microL, respectively. The subsequent recovery was quicker for CD8+ and NK cells, leading to a normalization within 3 months, whereas CD20+ and CD4+ cells required 1 or 2 years to enter the normal range. The CD4/CD8 ratio thus decreased after the nadir and remained less than 1. CD45RA+ CD4 cells and CD45RA+/CD45RO+ double-positive cells were less affected by CdA. Activated T cells, ie, HLA-DR+ cells, rarely decreased below the normal range and often recovered with an overshoot. CD10+ cells increased in the bone marrow posttreatment as an indication of normal B-cell regeneration in 16 of 36 (44%) patients. The quick regeneration of certain lymphoid subsets might explain the lack of late infections in CdA-treated HCL patients.