Lymphocyte subset analysis by flow cytometry. Comparison of three different staining techniques and effects of blood storage

Rationale and design of the Dog Aging Project precision cohort: a multi-omic resource for longitudinal research in geroscience

A significant challenge in multi-omic geroscience research is the collection of high quality, fit-for-purpose biospecimens from a diverse and well-characterized study population with sufficient sample size to detect age-related changes in physiological biomarkers. The Dog Aging Project designed the precision cohort to study the mechanisms underlying age-related change in the metabolome, microbiome, and epigenome in companion dogs, an emerging model system for translational geroscience research. One thousand dog-owner pairs were recruited into cohort strata based on life stage, sex, size, and geography. We designed and built a novel implementation of the REDCap electronic data capture system to manage study participants, logistics, and biospecimen and survey data collection in a secure online platform. In collaboration with primary care veterinarians, we collected and processed blood, urine, fecal, and hair samples from 976 dogs. The resulting data include complete blood count, chemistry profile, immunophenotyping by flow cytometry, metabolite quantification, fecal microbiome characterization, epigenomic profile, urinalysis, and associated metadata characterizing sample conditions at collection and during lab processing. The project, which has already begun collecting second- and third-year samples from precision cohort dogs, demonstrates that scientifically useful biospecimens can be collected from a geographically dispersed population through collaboration with private veterinary clinics and downstream labs. The data collection infrastructure developed for the precision cohort can be leveraged for future studies. Most important, the Dog Aging Project is an open data project. We encourage researchers around the world to apply for data access and utilize this rich, constantly growing dataset in their own work.

Peripheral blood mononuclear cell phenotype and function are maintained after overnight shipping of whole blood

Same day processing of biospecimens such as blood is not always feasible, which presents a challenge for research programs seeking to study a broad population or to characterize patients with rare diseases. Recruiting sites may not be equipped to process blood samples and variability in timing and technique employed to isolate peripheral blood mononuclear cells (PBMCs) at local sites may compromise reproducibility across patients. One solution is to send whole blood collected by routine phlebotomy via overnight courier to the testing site under ambient conditions. Determining the impact of shipping on subsequent leukocyte responses is a necessary prerequisite to any experimental analysis derived from transported samples. To this end, whole blood was collected from healthy control subjects and processed fresh or at 6, 24 and 48 h after collection and handling under modeled shipping conditions. At endpoint, whole blood was assessed via a complete blood count with differential and immunophenotyped using a standardized panel of antibodies [HLADR, CD66b, CD3, CD14, CD16]. PBMCs and neutrophils were isolated from whole blood and subjected to ex vivo stimulation with lipopolysaccharide and heat-killed Staphylococcus aureus. Stimulated release of cytokines and chemokines was assessed by cytometric bead array. RNA was also isolated from PBMCs to analyze transcriptional changes induced by shipping. The complete blood count with differential revealed that most parameters were maintained in shipped blood held for 24 h at ambient temperature. Immunophenotyping indicated preservation of cellular profiles at 24 h, although with broadening of some populations and a decrease in CD16 intensity on classical monocytes. At the transcriptional level, RNAseq analysis identified upregulation of a transcription factor module associated with inflammation in unstimulated PBMCs derived from whole blood shipped overnight. However, these changes were limited in both scale and number of impacted genes. Ex vivo stimulation of PBMCs further revealed preservation of functional responses in cells isolated from shipped blood held for 24 h at ambient temperature. However, neutrophil responses were largely abrogated by this time. By 48 h neither cell population responded within normal parameters. These findings indicate that robust immunophenotyping and PBMC stimulated response profiles are maintained in whole blood shipped overnight and processed within 24 h of collection, yielding results that are representative of those obtained from the sample immediately following venipuncture. This methodology is feasible for many patient recruitment sites to implement and allows for sophisticated immunological analysis of patient populations derived from large geographic areas. With regard to rare disease research, this meets a universal need to enroll patients in sufficient numbers for immunoprofiling and discovery of underlying pathogenic mechanisms.

Effects of storage time and temperature on highly multiparametric flow analysis of peripheral blood samples; implications for clinical trial samples

We sought to determine the effect of time and temperature of blood sample storage before preparation of human peripheral blood mononuclear cells (PBMCs) by Ficoll-hypaque density gradient centrifugation. Blood samples from healthy donors were stored at room temperature (RT) or refrigerated at 4°C before preparation of PBMCs. Cell yield and viability, and proportions of major cell populations within PBMCs, as determined by fluorescence flow cytometry, were assessed for both fresh and cryopreserved samples. Highly multiparametric mass cytometry was performed on cryopreserved PBMCs. We found that refrigeration had marked negative effects on subsequent PBMC yield. Storage at RT led to co-purification of low density neutrophils with PBMCs, but had no detectable effects on the proportions of multiple cell subsets including, but not limited to, monocytes, NK cells, B cells, Treg cells, and naïve, central memory and effector memory CD4⁺ and CD8⁺ T cells and CD45RA-positive terminal effector CD8⁺ T cells. Expression of a number of cell surface receptors, including CXCR5, CCR6, CXCR3 and TIGIT, but not CD247 was reduced after RT storage before PBMC preparation, and this effect correlated with the degree of low density neutrophil contamination. As such, when PBMC preparation cannot be undertaken immediately after blood draw, storage at RT is far superior to refrigeration. RT storage leads to neutrophil activation, but does not compromise measurement of PBMC subset distribution. However caution must be applied to interpretation of cytometric measurements of surface molecules such as chemokine receptors.

A field method for cryopreservation of whole blood from a finger prick for later analysis with flow cytometry

OBJECTIVES

Flow cytometry is a powerful tool for investigating immune function, allowing for the quantification of leukocytes by subtype. Yet it has not been used extensively for field work due to perishable reagents and the need for immediate analysis of samples. To make flow cytometry more accessible, we devise and evaluate a field protocol for freezing capillary blood.

MATERIALS AND METHODS

We collected finger prick blood samples from 110 volunteers, age 18 to 42. Blood samples were analyzed immediately for 18 cell surface markers. Aliquots of whole blood were frozen in the vapor phase of a liquid nitrogen tank with 10% dimethyl sulfoxide in medium. Samples were analyzed on a Guava EasyCyte HT flow cytometer after 2, 4, or 14 weeks.

RESULTS

Major lymphocyte fractions in frozen samples were correlated with fresh values (T-cells: r = 0.82; Natural Killer [NK] cells: r = 0.64; CD4: r = 0.67; CD8: r = 0.82; Naïve CD4: r = 0.73, Naïve CD8: r = 0.71; B-cells: r = 0.73; all p < 0.001), and mean values were similar to those from fresh samples. However, correlations for smaller subsets of CD4 and B cells were generally poor. Some differences resulted from changes in non-specific binding for some antibody-conjugate pairs. Cryopreservation also resulted in a reduction in granulocytes more than lymphocytes.

DISCUSSION

Our results suggest that antibody/fluorochrome combinations should be validated before use on frozen samples, and that functional changes in cells may affect some cell markers. However, this simple freezing protocol utilizing finger pricks, whole blood, and a liquid nitrogen shipping tank is viable for obtaining samples for flow cytometry under field conditions.

The impact of blood-processing time on the proteome of human peripheral blood mononuclear cells

Human peripheral blood mononuclear cells (PBMC) are key to several diagnostics assays and basic science research. Blood pre-analytical variations that occur before obtaining the PBMC fraction can significantly impact the assays results, including viability, composition, integrity, and gene expression changes of immune cells. With this as motivation, we performed a quantitative shotgun proteomics analysis using Isobaric Tag for Relative and Absolute Quantitation (iTRAQ 8plex) labeling to compare PBMC obtained from 24 h-stored blood at room temperature versus freshly isolated. We identified a total of 3195 proteins, of which 245 were differentially abundant (101 upregulated and 144 downregulated). Our results revealed enriched pathways of downregulated proteins related to exocytosis, localization, vesicle-mediated transport, cell activation, and secretion. In contrast, pathways related to exocytosis, neutrophil degranulation and activation, granulocyte activation, leukocyte degranulation, and myeloid leukocyte activation involved in immune response were enriched in upregulated proteins, which may indicate probable granulocyte contamination and activation due to blood storage time and temperature. Examples of upregulated proteins in the 24 h-PBMC samples are CAMP, S100A8, LTA4H, RASAL3, and S100A6, which are involved in an adaptive immune system and antimicrobial activity, proinflammatory mediation, aminopeptidase activities, and naïve T cells survival. Moreover, examples of downregulated proteins are NDUFA5, TAGLN2, H3C1, TUBA8, and CCT2 that are related to the cytoskeleton, cell junction, mitochondrial respiratory chain. In conclusion, the delay in blood-processing time directly impacts the proteomic profile of human PBMC, possibly through granulocyte contamination and activation.

Effects of maternal L-proline supplementation on inflammatory cytokines at the placenta and fetus interface of mice

Dietary L-proline (proline) supplementation during gestation enhances fetal survival and placental development in mice. The objective of the present study was to test the hypothesis that this beneficial effect of proline was associated with alterations in inflammatory response at the placenta and fetus interface. Populations of immune cells present in peripheral blood mononuclear cells (PBMC) were determined by flow cytometry analysis. The concentrations of immunoglobulins in plasma, and the concentrations of cytokines in plasma, uterus, placenta, and amniotic fluid were measured using a bead-based immunoassay. The data showed that proline supplementation led to higher (P < 0.05) populations of B lymphocytes (CD3^-CD19⁺), natural killer (NK) cells (CD3^-NK1.1⁺), and dendritic cells (DCs, CD11c⁺MHCII⁺) in peripheral blood, as compared with the controls. Conversely, mice fed a proline-supplemented diet had a lower population of neutrophils (CD11b⁺F4/80^-). Further study showed that proline supplementation decreased (P < 0.05) the concentrations of (1) interleukin (IL)-23, IL-1α, and IL-6 in plasma; (2) IL-6 in the uterus; and (3) tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein (MCP)-1, and IL-17 in the placenta; and (4) interferon (IFN)-γ in amniotic fluid, compared with controls. Conversely, proline supplementation resulted in higher (P < 0.05) concentrations of (1) IL-10, IL-17 and granulocyte-macrophage colony-stimulating factor (GM-CSF) in plasma; (2) IL-10 and IL-1α in the uterus; and (3) IL-1α, IL-1β, IL-10, IL-27, and IFN-β in amniotic fluid, compared with controls. Moreover, concentrations of immunoglobulin (Ig) G2b and IgM were enhanced (P < 0.05) by proline administration. Taken together, our results reveal a regulatory effect of proline in the immunological response at the maternal-fetal interface, which is critical for embryonic development and fetal survival.

Skin-homing T-cell responses associated with Demodex infestation and rosacea

AIMS

Our aim was to investigate the skin-homing T-cell immune responses triggered in patients with Demodex infestation and/or rosacea.

METHODS

Collected whole blood samples were divided into four groups: control subjects; nonrosacea patients with Demodex infestation (Demodex group); papulopustular rosacea (PPR) patients without Demodex infestation (Rosacea group); and PPR patients with Demodex infestation (Rosacea/Demodex group). Following ex vivo activation, skin-homing CLA+CD4+ T-cell subset levels were monitored by flow cytometry.

RESULTS

When compared with control subjects, among skin-homing CD4+ T-cell subsets analysed, Demodex patients had higher T_H 9 and T_reg cell levels; Rosacea subjects displayed elevated T_H 1 cell levels; and Rosacea/Demodex patients exhibited increased frequencies of T_H 9 and T_H 22 cells. In contrast to Rosacea subjects, Rosacea/Demodex group members displayed higher T_H 2 cell levels; and when compared with Demodex groups, they had higher T_H 1 and T_H 2 but lower T_reg cell levels. Demodex group members also exhibited higher T_reg but lower T_H 1 and T_H 22 levels than Rosacea/Demodex group subjects.

CONCLUSIONS

The skin-homing T-cell responses associated with Demodex infestation and rosacea formation seem to influence each other. The present as well as future studies could contribute to the development of effective treatment strategies for demodicosis and rosacea.

Suitability of small diagnostic peripheral-blood samples for cell-therapy studies

BACKGROUND AIMS

Primary hematopoietic stem and progenitor cells (HSPCs) are key components of cell-based therapies for blood disorders and are thus the authentic substrate for related research. We propose that ubiquitous small-volume diagnostic samples represent a readily available and as yet untapped resource of primary patient-derived cells for cell- and gene-therapy studies.

METHODS

In the present study we compare isolation and storage methods for HSPCs from normal and thalassemic small-volume blood samples, considering genotype, density-gradient versus lysis-based cell isolation and cryostorage media with different serum contents. Downstream analyses include viability, recovery, differentiation in semi-solid media and performance in liquid cultures and viral transductions.

RESULTS

We demonstrate that HSPCs isolated either by ammonium-chloride potassium (ACK)-based lysis or by gradient isolation are suitable for functional analyses in clonogenic assays, high-level HSPC expansion and efficient lentiviral transduction. For cryostorage of cells, gradient isolation is superior to ACK lysis, and cryostorage in freezing media containing 50% fetal bovine serum demonstrated good results across all tested criteria. For assays on freshly isolated cells, ACK lysis performed similar to, and for thalassemic samples better than, gradient isolation, at a fraction of the cost and hands-on time. All isolation and storage methods show considerable variation within sample groups, but this is particularly acute for density gradient isolation of thalassemic samples.

DISCUSSION

This study demonstrates the suitability of small-volume blood samples for storage and preclinical studies, opening up the research field of HSPC and gene therapy to any blood diagnostic laboratory with corresponding bioethics approval for experimental use of surplus material.

Modifications in flow cytometric estimation of t cell subsets and b cells in peripheral blood to reduce the cost of investigation

The development of monoclonal antibodies combined with flow cytometry has revolutionized the analysis of lymphocyte subsets. These newer methods using the Q-prep leucocyte preparation system require only 1-2 ml of blood as compared to 10 ml required traditionally. One of the main impediments in the use of this superior technology in Indian laboratories has been the high cost of reagents. This study evaluated methods to reduce the cost of assays. In the first experiment from 26 healthy subjects, 2ml venous blood samples in EDTA (ethylenediamine tetra-acetate) were obtained. Each sample was divided into two equal portions, one portion was stained using diluted monoclonal antibody, whereas the other portion was stained using standard concentrations of antibodies. In the second experiment, blood samples from 12 subjects were again divided into 2 portions; one portion of each pair was processed using commercial Q-prep reagents while the other portion was processed using our own reagents. In the first experiment, which evaluated use of a diluted antibody against the standard recommended concentrations, a 5-tube panel that estimated CD3, CD4, CD8, CD20 was used. In the second experiment CD3, CD4 and CD8 were estimated. The total cost per sample for a 5-panel estimation was however reduced from $39.11 to $1.10.Given the proven advantages of using a whole blood stain-lyse method for T cell subset estimations, its use should be encouraged in developing country settings. With the suggested methods the whole blood Q-prep could be performed at appreciably reduced costs, without loss in precision.

Long lasting local and systemic inflammation after cerebral hypoxic ischemia in newborn mice

Background

Hypoxic ischemia (HI) is an important cause of neonatal brain injury and subsequent inflammation affects neurological outcome. In this study we performed investigations of systemic and local activation states of inflammatory cells from innate and adaptive immunity at different time points after neonatal HI brain injury in mice.

Methodology/Principal Findings

We developed a multiplex flow cytometry based method combined with immunohistochemistry to investigate cellular immune responses in the brain 24 h to 7 months after HI brain injury. In addition, functional studies of ex vivo splenocytes after cerebral hypoxic ischemia were performed. Both central and peripheral activation of CD11b⁺ and CD11c⁺ antigen presenting cells were seen with expression of the costimulatory molecule CD86 and MHC-II, indicating active antigen presentation in the damaged hemisphere and in the spleen. After one week, naïve CD45rb⁺ T-lymphocytes were demonstrated in the damaged brain hemisphere. In a second phase after three months, pronounced activation of CD45rb⁻ T-lymphocytes expressing CD69 and CD25 was seen in the damaged hemisphere. Brain homogenate induced proliferation in splenocytes after HI but not in controls.

Conclusions/Significance

Our findings demonstrate activation of both local and systemic immune responses months after hypoxic ischemic neonatal brain injury. The long term immune activation observed is of general importance for future studies of the inflammatory response after brain injury as most previous studies have focused on the first few weeks after damage, while the effects of the late inflammation phase may be missed. Furthermore, the self-reactive component raises the question if there is a correlation with development of autoimmune brain disease later in life.

Shipping blood to a central laboratory in multicenter clinical trials: effect of ambient temperature on specimen temperature, and effects of temperature on mononuclear cell yield, viability and immunologic function

Background

Clinical trials of immunologic therapies provide opportunities to study the cellular and molecular effects of those therapies and may permit identification of biomarkers of response. When the trials are performed at multiple centers, transport and storage of clinical specimens become important variables that may affect lymphocyte viability and function in blood and tissue specimens. The effect of temperature during storage and shipment of peripheral blood on subsequent processing, recovery, and function of lymphocytes is understudied and represents the focus of this study.

Methods

Peripheral blood samples (n = 285) from patients enrolled in 2 clinical trials of a melanoma vaccine were shipped from clinical centers 250 or 1100 miles to a central laboratory at the sponsoring institution. The yield of peripheral blood mononuclear cells (PBMC) collected before and after cryostorage was correlated with temperatures encountered during shipment. Also, to simulate shipping of whole blood, heparinized blood from healthy donors was collected and stored at 15°C, 22°C, 30°C, or 40°C, for varied intervals before isolation of PBMC. Specimen integrity was assessed by measures of yield, recovery, viability, and function of isolated lymphocytes. Several packaging systems were also evaluated during simulated shipping for the ability to maintain the internal temperature in adverse temperatures over time.

Results

Blood specimen containers experienced temperatures during shipment ranging from -1 to 35°C. Exposure to temperatures above room temperature (22°C) resulted in greater yields of PBMC. Reduced cell recovery following cryo-preservation as well as decreased viability and immune function were observed in specimens exposed to 15°C or 40°C for greater than 8 hours when compared to storage at 22°C. There was a trend toward improved preservation of blood specimen integrity stored at 30°C prior to processing for all time points tested. Internal temperatures of blood shipping containers were maintained longer in an acceptable range when warm packs were included.

Conclusions

Blood packages shipped overnight by commercial carrier may encounter extreme seasonal temperatures. Therefore, considerations in the design of shipping containers should include protecting against extreme ambient temperature deviations and maintaining specimen temperature above 22°C or preferably near 30°C.

Quality monitoring of HIV-1-infected and uninfected peripheral blood mononuclear cell samples in a resource-limited setting

Human immunodeficiency virus type 1 (HIV-1) vaccine and natural history studies are critically dependent on the ability to isolate, cryopreserve, and thaw peripheral blood mononuclear cell (PBMC) samples with a high level of quality and reproducibility. Here we characterize the yield, viability, phenotype, and function of PBMC from HIV-1-infected and uninfected Ugandans and describe measures to ascertain reproducibility and sample quality at the sites that perform cryopreservation. We have developed a comprehensive internal quality control program to monitor processing, including components of method validation. Quality indicators for real-time performance assessment included the time from venipuncture to cryopreservation, time for PBMC processing, yield of PBMC from whole blood, and viability of the PBMC before cryopreservation. Immune phenotype analysis indicated lowered B-cell frequencies following processing and cryopreservation for both HIV-1-infected and uninfected subjects (P < 0.007), but all other major lymphocyte subsets were unchanged. Long-term cryopreservation did not impact function, as unstimulated specimens exhibited low background and all specimens responded to staphylococcal enterotoxin B (SEB) by gamma interferon and interleukin-2 production, as measured by intracellular cytokine staining. Samples stored for more than 3 years did not decay with regard to yield or viability, regardless of HIV-1 infection status. These results demonstrate that it is possible to achieve the high level of quality necessary for vaccine trials and natural history studies in a resource-limited setting and provide strategies for laboratories to monitor PBMC processing performance.

Assessment of long-term radiotoxicity after treatment with the low-dose-rate alpha-particle-emitting radioimmunoconjugate (227)Th-rituximab

PURPOSE

The anti-CD20 antibody rituximab labelled with the alpha-particle-emitting radionuclide (227)Th is of interest as a radiotherapeutic agent for treatment of lymphoma. Complete regression of human lymphoma Raji xenografts in 60% of mice treated with 200 kBq/kg (227)Th-rituximab has been observed. To evaluate possible late side effects of (227)Th-rituximab, the long-term radiotoxicity of this potential radiopharmaceutical was investigated.

METHODS

BALB/c mice were injected with saline, cold rituximab or 50, 200 or 1,000 kBq/kg (227)Th-rituximab and followed for up to 1 year. In addition, nude mice with Raji xenografts treated with various doses of (227)Th-rituximab were also included in the study. Toxicity was evaluated by measurements of mouse body weight, white blood cell (WBC) and platelet counts, serum clinical chemistry parameters and histological examination of tissues.

RESULTS

Only the 1,000 kBq/kg dosage resulted in decreased body weight of the BALB/c mice. There was a significant but temporary decrease in WBC and platelet count in mice treated with 400 and 1,000 kBq/kg (227)Th-rituximab. Therefore, the no-observed-adverse-effect level (NOAEL) was 200 kBq/kg. The maximum tolerated activity was between 600 and 1,000 kBq/kg. No significant signs of toxicity were observed in histological sections in any examined tissue. There were significantly (p < 0.05), but transiently, higher concentrations of serum bile acids and aspartate aminotransferase in mice treated with either (227)Th-rituximab or non-labelled antibody when compared with control mice. The maximum tolerated dose to bone marrow was between 2.1 and 3.5 Gy.

CONCLUSION

Therapeutically relevant dose levels of (227)Th-rituximab were well tolerated in mice. Bone marrow suppression, as indicated by decrease in WBC count, was the dose-limiting radiotoxicity. These toxicity data together with anti-tumour activity data in a CD20-positive xenograft mouse model indicate that therapeutic effects could be obtained with relatively safe dosage levels of the radioimmunoconjugate.

Increased percentage of B cells in patients with more advanced hepatocellular carcinoma

To compare immunologic phenotypes between (1) hepatocellular carcinoma (HCC) patients and a healthy population and (2) more advanced and early stage HCC patients, we studied 45 HCC patients and 46 healthy controls from January 2006 to January 2008. Using fluorescent activated cell sorter (FACS) analysis, HCC patients were demonstrated to exhibit stronger phagocytosis of granulocytes and monocytes and more peripheral blood mononuclear cells (PBMCs) in the G2/M phase compared with healthy volunteers. By contrast, lower percentages of B and T(h) lymphocytes were also found in the peripheral blood of HCC patients than in the healthy population. Most importantly, a higher percentage of B cells was found in patients with advanced HCC than in those with early HCC in terms of TNM stage (II and III vs I, p = 0.004), the Japanese Integrated Scoring system (2-3 vs 0-1, p = 0.0235), and tumor numbers (> or =2 vs 1, p = 0.005). In conclusion, our findings suggested that HCC patients might exhibit enhanced innate immunity and reduced adaptive immunity compared with healthy volunteers. A higher percentage of B cells was found in patients with more advanced HCC compared with patients with early stage HCC, which might serve as an indicator of the severity of HCC.

Targeted cancer therapy with a novel low-dose rate alpha-emitting radioimmunoconjugate

Alpha-emitting radionuclides are highly cytotoxic and are of considerable interest in the treatment of cancer. A particularly interesting approach is in radioimmunotherapy. However, alpha-emitting antibody conjugates have been difficult to exploit clinically due to the short half-life of the radionuclides, low production capability, or limited source materials. We have developed a novel technology based on the low-dose rate alpha-particle-emitting nuclide (227)Th, exemplified here using the monoclonal antibody rituximab. In vitro, this radioimmunoconjugate killed lymphoma cells at Becquerel per milliliter (Bq/mL) levels. A single injection of (227)Th-rituximab induced complete tumor regression in up to 60% of nude mice bearing macroscopic (32-256 mm(3)) human B-lymphoma xenografts at Becquerel per gram (Bq/g) levels without apparent toxicity. Therapy with (227)Th-rituximab was significantly more effective than the control radioimmunoconjugate (227)Th-trastuzumab and the standard beta-emitting radioimmunoconjugate for CD20(+) lymphoma(90)Y-tiuxetan-ibritumomab. Thorium-227 based constructs may provide a novel approach for targeted therapy against a wide variety of cancers.

Immuno-monitoring of CD8+ T cells in whole blood versus PBMC samples

The study of natural T cell responses against pathogens or tumors, as well as the assessment of new immunotherapy strategies aimed at boosting these responses, requires increasingly precise ex vivo analysis of blood samples. For practical reasons, studies are often performed using purified PBMC samples, usually cryopreserved. Here, we report on FACS analyses of peripheral blood T cells, performed by direct antibody staining of non-purified total blood. For comparison, fresh PBMC, purified by Ficoll, were analysed. Our results show that the latter method can induce a bias in subpopulation distribution, in particular of CD8+ T cells, and sometimes lead to inaccurate measurement of antigen specific CD8+ T cell responses. Direct analysis of total blood can be applied to longitudinal immuno-monitoring of T cell-based therapy. While the need to purify and cryopreserve PBMC for subsequent studies is obvious, the use of whole blood has the advantage of providing unbiased results and only small amounts of blood are used.

T cell subsets and mortality in older community-dwelling women

The relationship between specific T cell subset alterations and mortality has not been well characterized in older adults. The specific aim was to determine whether specific T cell subsets are associated with an increased risk of death. We conducted a case-control study of T cell subsets (CD4+ and CD8+ T cells, and subsets of these cells defined by expression or non-expression of CD28, CD45RA, and CD45RO) nested within two complementary prospective cohorts of women aged 65 and over living in the community, the Women's Health and Aging Studies (WHAS). Cases consisted of 61 women who died during 5 years of follow-up, and controls consisted of 61 women matched by age, frailty, and morbidities who survived during 7 years of follow-up. There were no significant differences between cases and controls in any of the T cell subsets studied. When analyses were stratified by frailty status, these data suggest that CD8+CD28- lymphocyte counts were significantly higher among women who were frail compared with pre-frail and non-frail women.

Use of whole blood directly for single-cell gel electrophoresis (comet) assay in vivo and white blood cells for in vitro assay

The present study investigated the use of whole blood from humans and rats directly for single-cell gel electrophoresis (comet) assay. As little as 20 microl of whole blood was sufficient for comet assay, and the comet images obtained from whole blood were not different from those obtained from isolated lymphocytes. The DNA remained intact up to 4 h at 4 degrees C after isolation and had no observable strand breakage, when whole blood was cryopreserved (at -80 degrees C) in 10% pre-cooled DMSO up to 60 days. To demonstrate that the whole-blood technique could be applied to in vivo studies, we injected rats with a known carcinogen Fe/NTA and measured DNA strand breaks in whole blood in comparison with isolated lymphocytes. We showed that Fe/NTA injection resulted in similar extent of DNA strand breakage in both whole blood and lymphocytes, indicating that whole-blood method can be used for in vivo genotoxic studies. One disadvantage of the whole-blood technique is that whole blood cannot be used for in vitro studies because of the interferences from red blood cell (RBC) components. However, this problem can be overcome by prior hemolysis of RBCs and a brief centrifugation to obtain white blood cells (WBCs), which can then be used for in vitro incubation with genotoxic compounds before comet assay. Overall, this whole-blood technique for comet assay is expected to provide a simple, rapid, and cost-effective alternative for the existing comet assay using isolated lymphocytes in situations such as when time and cost are limiting factors.

Effect of blood transfusion during radiotherapy on the immune function of patients with cancer of the uterine cervix: role of interleukin-10

PURPOSE

To analyze prospectively the effects of blood transfusion administered during radiotherapy (RT) on the immune function of patients with locally advanced cervical cancer.

METHODS AND MATERIALS

In a total of 15 patients, 7 transfused and 8 untransfused, lymphocyte populations, including CD3+, CD4+, and CD8+ T-cell subsets, B cells (CD19+), and natural killer (NK) cells (CD56+, CD16+, CD3-) were studied before (i.e., time 0), during (i.e., times 1 and 2), and after (i.e., time 3) therapy. Expression of the early (CD25) and late (HLA-DR) activation markers on CD3+ T cells, the intracellular levels of perforin in CD8+ and CD56+ cells, and interferon (IFN)-gamma, interleukin (IL)-2, and IL-4 in CD4+ and CD8+ T cells were also measured. NK cell cytotoxicity against the NK-sensitive target K-562 cells and CD8+ T-cell-directed cytotoxicity against OKT3 hybridoma cells were also assessed. Finally, the plasma levels of the immunoregulatory cytokine IL-10 were analyzed by enzyme-linked immunosorbent assay.

RESULTS

The mean absolute number of all lymphocyte subsets compared with pretreatment levels decreased significantly during RT of both transfused and untransfused patients (p >0.001), with no detectable differences between the two groups in terms of total lymphocytes or relative numbers of CD3+ and CD4+ T cells, CD56+ NK cells, or CD19+ B cells. In contrast, concomitant with an inversion of the CD4/CD8 ratio, a significant increase in the number of CD8+ T cells at time 2 and CD3+ T cells, CD8+ T cells, and NK cells at time 3 was found in the transfused patients compared with the untransfused group. The percentages of CD25+/CD3+ T cells and HLA-DR+/CD3+ T cells increased during RT of the untransfused patients, but CD3+ T cells showed decreased CD25 expression and increased HLA-DR expression in the transfused group. An increase of CD8+ IFN-gamma+ T cells with a concomitant decrease in CD8+ IL-2+ T cells was found in the transfused vs. untransfused group, and no differences were noted in the percentage of CD4+ IFN-gamma+ T cells and CD4+ IL-2+ T cells. The proportion of perforin-positive CD8+ and CD56+ cells was higher in the transfused group than in the untransfused group. However, CD56+ cells and CD8+ T cells from the transfused patients showed markedly diminished cytotoxic function. Finally, IL-10 was detected only in the plasma of the transfused patients.

CONCLUSION

Blood transfusion during primary RT for cervical cancer profoundly alters the magnitude and characteristics of radiation-induced immunosuppression. Elevated serum IL-10 in transfused patients may play a role in the disregulation of lymphocyte function, in particular, the depression of NK- and T-cell cytotoxicity. Investigation of alternatives to blood transfusion during RT that do not diminish host immunity is warranted.

Flow cytometric analysis of European flat oyster, Ostrea edulis, haemocytes using a monoclonal antibody specific for granulocytes

The importance of haemocytes in mollusc defence mechanisms can be inferred from their functions. They participate in pathogen elimination by phagocytosis (Cheng, 1981; Fisher, 1986). Hydrolytic enzymes and cytotoxic molecules produced by haemocytes contribute to the destruction of pathogenic organisms (Cheng, 1983; Leippe & Renwrantz, 1988; Charlet et al., 1996; Hubert et al., 1996; Roch et al., 1996). Haemocytes may also be involved in immunity modulation by the production of cytokines and neuropeptides (Hughes et al., 1990; Stefano et al., 1991; Ottaviani et al., 1996). As a result, the literature dealing with bivalve haemocyte studies has increased during the last two decades. Most of these publications use microscopy for morphological analysis (Seiler & Morse, 1988; Auffret, 1989; Hine & Wesney, 1994; Giamberini et al., 1996; Carballal et al., 1997; Lopez et al., 1997; Nakayama et al., 1997), and functional analysis (e.g. phagocytosis) (Hinsch & Hunte, 1990; Tripp, 1992; Mourton et al., 1992; Fryer & Bayne, 1996; Mortensen & Glette, 1996). Flow cytometry represents a rapid technique applicable to both morphological and functional studies of cells in suspension. While the measurements based on autofluorescence provide information on cell morphology, the analyses with fluorescent markers including labelled antibodies, offer data on phenotyping and cell functions. As a result, its application has greatly contributed to the investigation of immunocyte functions and differentiation in vertebrates (Stewart et al., 1986; Rothe & Valet, 1988; Ashmore et al., 1989; Koumans-van Diepen et al., 1994; Rombout et al., 1996; Caruso et al., 1997). Some authors studied oyster haemocyte populations by flow cytometry based on cellular autofluorescence (Friedl et al., 1988; Fisher & Ford, 1988; Ford et al., 1994). However, no analysis using specific monoclonal antibodies has been reported to date. In this study, a protocol for studying European flat oyster, Ostrea edulis, haemocytes by flow cytometry using a monoclonal antibody specific for granulocytes and an indirect immunofluorescence technique have been developed. European flat oysters, Ostrea edulis, 7-9 cm in shell length were obtained from shellfish farms in Marenne Oléron bay (Charente Maritime, France) on the French Atlantic coast. All individuals were purchased just before each experiment and processed without any previous treatment.

Stability of fresh and preserved fetal and adult lymphocyte cell surface markers

Delay between blood collection and immunophenotyping of peripheral blood (PB) and umbilical cord blood (UCB) lymphocytes occurs frequently. Holding media address this problem, but there are few reports of their limitations. We tested the ability of Cyto-Chex (CC) to preserve the ability of lymphocyte subpopulations to be immunophenotyped after time delays. Ten UCB and 10 PB specimens were kept up to 48 hr and then placed in CC for 1 week, with removal of aliquots for staining with CD3, CD4, CD8, CD19, and CD45 at intervals. There were no significant changes in the number of nonpreserved PB or UCB cells stained with any of the reagents after 48 hr. Aside from a small decrease in UCB B-cell numbers, there were no changes in UCB or PB lymphocyte numbers after placing them in CC for 1 week. However, PB and UCB CD19+ cells and CD8+ T cells lost capacity for bright staining after 1 week in CC. The results suggest that UCB and PB can be held for up to 48 hr before being placed in CC and then kept for up to 1 week in CC with no decrease in T-cell numbers and only a minor reduction of B-cell numbers, albeit with a marked reduction in staining intensity.

Circulating CD8+ T cells in polymyalgia rheumatica and giant cell arteritis: a review

BACKGROUND AND OBJECTIVE

During the last few years, there have been several studies on T cell subsets in polymyalgia rheumatica (PMR) and giant cell arteritis (GCA), with conflicting results. Whereas some authors have found normal values of circulating CD8+ T cells, others have found a decreased number. Furthermore, in some studies, the level of CD8+ cells was found to be related to disease activity, and it has been proposed that a decrease of CD8+ T cells be used as a diagnostic criterion for PMR. The purpose of our study was to determine the value of assessing T cell subsets in PMR and GCA.

METHODS

T lymphocyte subsets were determined by flow cytometry using a whole blood lysis technique in the following groups: 28 PMR and 6 GCA patients before corticosteroid treatment, 20 PMR and 12 GCA patients in clinical remission with steroid treatment, 55 PMR patients in remission without steroid treatment, 17 rheumatoid arthritis (RA) patients before treatment, and 18 age-matched controls with noninflammatory conditions. Total white cell, lymphocyte, and platelet counts, hemoglobin, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were measured by routine techniques. Comparisons were made by the Student's t-test and the Mann-Whitney test. A MEDLINE database search for studies published between 1983 and 1997 was performed.

RESULTS

Compared with noninflammatory controls, CD8+ T cells were not reduced before steroid treatment in patients with active PMR/GCA in proportion (P =.7) or absolute numbers (P =.1). Patients with active disease had significantly lower hemoglobin levels and higher platelet counts, CRP, and ESR than noninflammatory controls (P <.05). When compared with active RA, CD8+ T cells were not reduced in patients with active PMR in proportion (P =.5) or absolute numbers (P =.2). Between these two groups, RA patients were significantly younger (P =.003) and had lower ESR values (P =.003). We did not find significant differences between patients with active PMR/GCA and those in remission with steroid therapy, except for the lower hemoglobin levels and higher platelet count, CRP, and ESR in the active disease group (P <.05). The same results were found when patients with active disease were compared with PMR in remission and no longer on steroid therapy, the only significant differences were those parameters reflecting the acute phase response (hemoglobin levels, platelet count, CRP and ESR).

CONCLUSIONS

This study does not confirm the previous findings that the proportion or number of circulating CD8+ T cells are reduced in patients with active PMR/GCA. The utility of the determination of CD8+ T cells for diagnostic and prognostic purpose should be evaluated in a large multicenter study.

Effects of concurrent cisplatinum administration during radiotherapy vs. radiotherapy alone on the immune function of patients with cancer of the uterine cervix

PURPOSE

To compare the effects of concurrent administration of cisplatinum (40 mg/m(2)/weekly) with radiation therapy (C-RT) to those induced by radiation therapy alone (RT) on the immune function of patients with locally advanced cervical cancer.

METHODS AND MATERIALS

In 8 prospectively randomized patients (i.e., 4 receiving RT vs. 4 receiving C-RT), lymphocyte populations including CD3+, CD4+ and CD8+ T-cell subsets, B cells (CD19+) and natural killer cells (CD56+, CD16+, CD3-) were studied before, during, and after therapy. Expression of the activation marker CD25 on CD3+ T cells, intracellular levels of perforin in CD8+ and CD56+ cells, and interferon-gamma (IFN-gamma) and IL-2 in CD4+ and CD8+ T cells was also measured. Finally, lymphoblast transformation and natural killer (NK) cytotoxic activity were assessed.

RESULTS

Both RT and C-RT significantly decreased the mean absolute number of all lymphocyte subsets compared to pretreatment levels (p > 0.001). However, no differences were detected in the characteristics or the magnitude of the lymphopenia induced by the two treatments. Both RT and C-RT increased similarly the percentages of CD25-positive lymphocytes (p > 0.001), and significantly decreased PHA-induced T-cell lymphoblast transformation (p > 0.001) and NK cytotoxic activity against K562 cells (p > 0.001). The percentage of perforin-positive and CD8+ T cells was not altered during either treatment, whereas the percentage of perforin-positive and CD56+ cells was significantly reduced during both treatments, and correlated with reduced cytotoxicity against K562 cells. The percentages of CD8+ IFN-gamma+ and CD4+ IFN-gamma+ T cells as well as that of CD8+ IL-2+ and CD4+ IL2+ T cells were not significantly altered by C-RT compared to RT alone. Finally, with both regimens, NK cells and B-cell numbers showed a more rapid recovery than T-cell numbers.

CONCLUSION

Administration of concurrent cisplatinum to radiation may synergistically increase cytotoxic effects of radiation on tumor cells but does not alter the magnitude and the characteristics of radiation-induced immunosuppression.

Preservation of lymphocyte immunophenotype and proliferative responses in cryopreserved peripheral blood mononuclear cells from human immunodeficiency virus type 1-infected donors: implications for multicenter clinical trials. The ACTG Immunology Advanced Technology Laboratories

Human immunodeficiency virus type 1 (HIV-1) infection results in impaired immune function that can be measured by changes in immunophenotypically defined lymphocyte subsets and other in vitro functional assays. These in vitro assays may also serve as early indicators of efficacy when new therapeutic strategies for HIV-1 infection are being evaluated. However, the use of in vitro assays of immune function in multicenter clinical trials has been hindered by their need to be performed on fresh specimens. We assessed the feasibility of using cryopreserved peripheral blood mononuclear cells (PBMC) for lymphocyte immunophenotyping and for lymphocyte proliferation at nine laboratories. In HIV-1-infected patients with moderate CD4(+) lymphocyte loss, the procedures of density gradient isolation, cryopreservation, and thawing of PBMC resulted in significant loss of CD19(+) B cells but no measurable loss of total T cells or CD4(+) or CD8(+) T cells. No significant changes were seen in CD28(-) CD95(+) lymphocytes after cell isolation and cryopreservation. However, small decreases in HLA-DR(+) CD38(+) lymphocytes and of CD45RA(+) CD62L(+) were observed within both the CD4(+) and CD8(+) subsets. Fewer than 10% of those specimens that showed positive PBMC proliferative responses to mitogens or microbial antigens lost their responsiveness after cryopreservation. These results support the feasibility of cryopreserving PBMC for immunophenotyping and functional testing in multicenter AIDS clinical trials. However, small changes in selected lymphocyte subsets that may occur after PBMC isolation and cryopreservation will need to be assessed and considered in the design of each clinical trial.

Evaluation of a novel mononuclear cell isolation procedure for serological HLA typing

Despite recent advances in DNA-based genotyping, the microcytotoxicity test is still broadly used for the determination of human leukocyte class I antigens in patients as well as organ donors and also for the detection of HLA antibodies. Excellent purity and viability of peripheral blood mononuclear cells (PBMC) are essential for reliable HLA typing results. Background staining and cell loss can contribute to impaired typing results or even cause misinterpretations. A novel isolation procedure using cell preparation tubes (CPT) with prefilled Ficoll was compared with the standard Ficoll gradient. We determined the recovery, purity, and viability of the PBMC after several periods of storage. Finally, the isolated cells were used for HLA class I typing, and background reactivities were scored. By using the CPT method, the recovery of PBMC was significantly higher than recovery with the standard technique (P Collapse

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MESH Headings

• Cell Separation/methods
• Cell Survival
• Centrifugation, Density Gradient/methods
• Cytotoxicity, Immunologic
• Evaluation Studies as Topic
• Flow Cytometry
• Histocompatibility Testing
• Humans
• Leukocytes, Mononuclear/classification
• Leukocytes, Mononuclear/cytology
• Leukocytes, Mononuclear/physiology
• Specimen Handling
• Time Factors

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Grants Collapse

Affiliation(s)

P Schlenke Institute of Immunology and Transfusion Medicine, University of Luebeck School of Medicine, D23538 Luebeck, Germany.
H Klüter
M Müller-Steinhardt
H J Hammers
K Borchert
G Bein

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Localization of a T-cell epitope of superantigen toxic shock syndrome toxin 1 to residues 125 to 158

Toxic shock syndrome toxin 1 (TSST-1) is a member of the staphylococcal enterotoxin superantigen family. So far, little is known about T-cell epitopes on superantigens. In this study, we developed an improved method for localizing T-cell epitopes on superantigens that involved synthetic peptides plus costimulation by CD28 or phorbol myristate acetate. Using this method, we localized a T-cell epitope to a 34-residue region, TSST-1 (residues 125 to 158), which possessed only two of four TSST-1-targeted beta-chain variable element (Vbeta) specificities of T-cell receptors in humans and mice, human Vbeta2 and murine Vbeta15.

Comparison of four lymphocyte isolation methods applied to rodent T cell subpopulations and B cells

The aim of this study was to establish the validity of four lymphocyte isolation methods. The effects of three different erythrocyte lysing methods commonly used in the analysis of human cells, namely, lysis by ammonium chloride (AC), Becton Dickinson lysis (BDL) and the Coulter Q-Prep (CQP) preparation system were established by flow cytometry on rat lymphocyte subsets. The results were compared with those obtained with a Ficoll-Isopaque (FI) density gradient procedure adapted for use with rat cells. Lymphocyte isolation by AC or FI gradient was performed before labelling the lymphocyte subpopulations, whereas the BDL and CQP methods were performed after staining the cells in whole blood. The FI gradient yielded the lowest CD5+, CD4+ and CD25+ cell percentages. On the other hand AC lysis produced higher percentages of T cells and lower percentages of B cells than the other methods studied. The percentages obtained after BDL or CQP methods for T lymphocyte subsets and B cells were found to be reproducible. The commercial methods (BDL and CQP) are faster but rather expensive, whereas AC lysis and FI gradient separations are cheap and particularly useful when there is a requirement to culture the cells.

The effect of storage on immunophenotyping of sheep peripheral blood lymphocytes by flow cytometry

We have shown that when a whole blood method of cell staining is used for flow cytometric analysis of sheep lymphocytes (i.e. red cell lysis after addition of antibody), staining may be delayed for up to 48 h after blood collection without significant effect on expression of CD4, CD5, CD8 or B cell markers. If cells were stained immediately after blood collection, using the same whole blood method, and then fixed with paraformaldehyde, cell samples could be stored for 24 h without change in marker expression. However, by 7 days there was a significant decrease in the percentage of cells expressing CD8, T19 and B cell markers. Cryopreservation prior to staining was found to markedly affect the expression of all cell surface markers investigated. These results indicate that storage of sheep blood prior to flow cytometric analysis is feasible but may affect the results obtained. Thus is it important to standardise the handling of samples, especially when comparative studies are being undertaken.

Peripheral blood cell preparation influences the level of expression of leukocyte cell surface markers as assessed with quantitative multicolor flow cytometry

We have compared the influence of sample preparation upon the level of surface expression of T, B, and NK cell-related antigens as assessed by flow cytometry. Lysed whole blood (WBL), Ficoll-Paque separated peripheral blood lymphocyte (F-PBL), and frozen peripheral blood lymphocyte (Fr-PBL) were analyzed via single- and multicolor flow cytometry. The percentage of positive cells expressing the individual cell surface markers was not affected by the procedure for preparation of WBL, F-PBL, and Fr-PBL. In contrast, the fluorescence intensity level of individual cell surface markers varied depending on cell preparation. By using Quantum Simply Cellular (QSC) microbeads, the antibody binding capacity (ABC) of single-color stained cells was quantified and compared. The amount of monoclonal antibody (MAb) anti-CD3-FITC bound to Fr-PBL (mean ABC = 137,040) was significantly higher (P < 0.001) that the amounts bound to WBL (mean ABC = 112,410) and F-PBL (mean ABC = 107,738). In multicolor analysis, the fluorescence intensity of CD3-FITC and CD4-FITC was significantly higher on Fr-PBL than on WBL and F-PBL; CD8-PE and CD20-PerCP was significantly higher on WBL. Furthermore, the intensity of CD3 and CD4 was different on T-cell subsets. The intensity of CD3 staining in three-color analysis was lower than with single-color staining using the same fluorochrome. We conclude that particularly the method of cell preparation but also the selection of MAb combinations may influence the level of staining of certain lymphocyte antigens. This may be of relevance in the analysis of cellular activation and regulation of differentiation.

Comparison of the effects of Ficoll-Hypaque separation and whole blood lysis on results of immunophenotypic analysis of blood and bone marrow samples from patients with hematologic malignancies

We compared flow cytometric immunophenotyping results obtained by using the lysed whole blood method of sample preparation with those obtained by using Ficoll-Hypaque-separated cells on 44 consecutive specimens from patients with various hematologic malignancies. When the samples were analyzed as a group, seven antigens (CD2, CD3, CD5, CD11c, CD20, CD22, and CD34) demonstrated significantly different percentages of positively staining cells. When the samples were grouped by disease, results for patients with acute lymphocytic leukemia were discordant for CD22 and HLA-DR and results for patients with hairy cell leukemia were discordant for CD34. Most of the differences, however, were not with antigens critical to the evaluation of the malignancy. Additionally, the most frequent reason for differences in the percentage of positive cells was due to isotype control-based placement of the quadrant markers and not an actual discrepancy in staining. However, analysis of the CD34 antigen yielded eight instances in which staining of Ficoll-Hypaque-separated cells was essentially negative, but a clearly positive population was evident with the lysed preparation. This finding has important implications because of the prognostic significance of this antigen. Further studies are needed to determine the cause of this phenomenon.

Quality control in flow cytometry for diagnostic pathology: II. A conspectus of reference ranges for lymphocyte immunophenotyping

Immunophenotyping, as many other clinical assays, is interpreted only in the context of reference values obtained from healthy control individuals. While the use of these reference values, or ranges, has been commonplace in the clinical flow cytometry laboratory for well over a decade, there has been little consensus in standardizing how these values should be obtained, analyzed, or expressed. This report reviews the variables to be considered in establishing reference ranges and statistical methods which can be used. Additionally, examples are given of previously published reference ranges for a variety of specimens often submitted for immunophenotyping.

Comparison of a lysed whole blood method to purified cell preparations for lymphocyte immunophenotyping: differences between healthy controls and HIV-positive specimens

Although the majority of clinical laboratories now use a lysed whole blood (LWB) method for routine immunophenotyping, researchers wishing to perform other types of studies with lymphocytes from HIV+ patients may still need to use purified cell preparations, such as peripheral blood mononuclear cells (PBMC). A comparison study of the two methods was performed, using peripheral blood specimens from normal donors and from patients infected with the human immunodeficiency virus (HIV+). Reproducibility studies and several types of holding studies (both before and after specimen processing) were also performed. The results suggest that the two different methods of sample preparation have different effects upon abnormal patient specimens than those observed in healthy controls. Immunophenotyping results derived from the two different methods cannot be considered equivalent for the purposes of quantitating the presence of a particular type of cell.

Circulating T cell subtypes in polymyalgia rheumatica and giant cell arteritis: variation in the percentage of CD8+ cells with prednisolone treatment

OBJECTIVES

Some reports have described a decreased percentage of circulating CD8+ cells in patients with polymyalgia rheumatica and giant cell arteritis (PMR/GCA) before treatment and persisting for some months during treatment with corticosteroids. Other studies have found no such changes. There are overt methodological variations between these studies and there may also hidden differences, such as the timing of blood samples. The purpose of this study was to investigate T cell subtypes in patients with PMR/GCA while controlling for variables known to affect T cells.

METHODS

Circulating T cell subsets were measured in 36 patients with PMR/GCA before and during treatment with prednisolone. Blood samples during treatment were taken before the daily dose of prednisolone. The whole blood lysis method was used followed by flow cytometry.

RESULTS

Compared with controls, CD8+ cells were not reduced before treatment in patients with PMR/GCA (0.44 x 10(9)/l; 28% of lymphocytes). CD4+ cells were also normal (0.78 x 10(9)/l; 48% of lymphocytes). During treatment with prednisolone total T cells increased from 1.18 to 1.59 x 10(9)/l and CD4+ cells increased from 0.78 to 1.05 x 10(9)/l. The percentage of CD8+ cells decreased on treatment from 28 to 25%.

CONCLUSIONS

This study does not confirm the finding of some groups that the percentage of circulating CD8+ cells is reduced in patients with PMR/GCA before treatment. It does show that the percentage of CD8+ cells decreases during treatment with corticosteroids. This needs to be considered when designing studies of lymphocyte subsets in diseases treated with corticosteroids.

Triple immunofluorescence flow cytometry, using whole blood, of CD4+ and CD8+ lymphocytes expressing CD45RO and CD45RA

New fluorescent monoclonal antibody-dye conjugates permit three-color immunofluorescence analysis of leukocytes in whole blood using a single laser flow cytometer. The fluorochrome used in this study is a tandem conjugate of phycoerythrin (PE) and Cyan-5, which is excitable at 488 nm with a maximum in the emission spectrum at > 650 nm and it can be used together with PE and fluorescein isothiocyanate (FITC). The directly labelled monoclonal antibodies are incubated with unseparated anticoagulated blood and subsequently erythrocytes are lysed by a standardized automated procedure. The resulting leukocyte suspension can then be analyzed for three different surface markers in an individual sample of 100 microliters blood. When compared simultaneously with single-color analysis triple-color immunofluorescence yielded identical quantitative and qualitative results on various lymphocyte subpopulations. The efficacy of this method was evaluated by analyzing leukocytes of 42 healthy donors for the following markers: CD3, CD4, CD8, CD14, CD16, CD19, CD25, CD38, CD45RO, CD45RA, CD56, CD57, TCR-gamma/delta and HLA-DR. Of special interest was the finding that CD45RA and CD45RO are differently expressed in CD4 and CD8 cells. The reliability and convenience of this three-color analysis will make it possible to do more sophisticated examinations of subpopulations and their relevance in the monitoring of autoimmune diseases, immunodeficiency syndromes including AIDS and malignant disorders such as leukemias.

Lymphocyte immunophenotyping by flow cytometry in normal adults. Comparison of fresh whole blood lysis technique, Ficoll-Paque separation and cryopreservation

In the present report we have assessed the extent to which Ficoll-Paque separation and cryopreservation of mononuclear cells alter the measurement of lymphocyte subsets by flow cytometry. Standard Ficoll-Paque separation increased the percentage of CD4+, CD19+ and CD4+CD45RA+ cells, as well as decreasing that of CD8+, and CD4+CD29+ cells, compared to the fresh whole blood lysis technique. Moreover, cryopreservation caused a depletion of CD4+ p80+ cells, but normal whole blood values were restored following a short incubation.

In vivo exposure to ultraviolet radiation enhances pathogenic effects of murine leukemia virus, LP-BM5, in murine acquired immunodeficiency syndrome

LP-BM5 murine leukemia virus (MuLV) induces an immunodeficiency syndrome (MAIDS) in C57BL/6 mice which resembles immunological abnormalities observed in early stages of human AIDS. In our study, MAIDS virus-infected mice were exposed to low doses of ultraviolet radiation (UVR) before and after virus inoculation and compared with MAIDS-infected but not UVR-exposed mice. In all tested parameters (blood IgM levels; mitogenic responses to PHA, ConA, LPS and anti-mu; MLR; antigenic response to SRBC; enlargement and histopathologic changes of the spleen) we observed the same trend: changes due to MAIDS infection were more pronounced in the UVR-exposed group than in the unexposed group. Statistically significant differences between these two groups were seen for mitogenic responses at two different time points after virus inoculation. These results demonstrate that in vivo UVR exposure enhances the immunosuppressive effects of a retroviral infection. UVR exposure may affect the progression of AIDS in a similar manner.

Immunological evaluation of late complement component-deficient individuals

The possible contribution of additional immunologic variables to the susceptibility of late complement component-deficient individuals to meningococcal disease has not been systematically examined in previous studies. Thus, we studied three groups of patients: (1) 24 healthy individuals, (2) 8 complement-sufficient individuals with a history of recurrent bacterial meningitis, and (3) 19 complement-deficient individuals with prior meningococcal infection. No statistical differences were noted among the three groups for the following parameters: the absolute number and the percentage of lymphocytes; CD3+, CD4+, CD8+, CD20+, and CD16+ cells; and the CD4+/CD8+ ratio. The concentration of C4 and circulating immune complexes was also similar among the groups. The concentrations of IgG, IgM, and IgA were slightly, but significantly, decreased in the complement-deficient individuals. Of interest, the coefficient of spontaneous and lipopolysaccharide-stimulated activation of neutrophils was significantly depressed in the deficient individuals. We hypothesize that the terminal complement components may participate in maximal neutrophil activation.

The effect of the temperature and duration of sample storage on the measurement of lymphocyte subpopulations from HIV-1-positive and control subjects

EDTA-anticoagulated blood samples from 19 HIV-1-positive subjects and 13 healthy laboratory worker controls were analysed for three lymphocyte subpopulations (CD3, CD4, CD8 T cells) (lysed whole blood method, Becton Dickinson FACScan flow cytometer) at 0, 24, 48, 72 and 96 h after venesection, having been stored at either 4 degrees C, 12 degrees C, 16 degrees C or 21 degrees C. In samples stored at 4 degrees C and 12 degrees C there was a significant fall in both %CD3 and %CD 4, and a significant rise in %CD8. At 16 degrees C the %CD8 remained stable, while there were marginal rises in %CD3 and %CD4. At 21 degrees C, the %CD8 again remained stable, while %CD3 and %CD4 rose significantly with time. These trends were independent of HIV-1 status. At each temperature studied, the rates of change of lymphocyte subpopulations were independent of each other. These results suggest that a temperature range of 14-16 degrees C may be optimal for sample storage prior to measurement of T cell subsets. They emphasise the importance of strict control on conditions if samples are to be kept for any length of time before analysis.

Upregulation of lymphocyte beta-adrenergic receptor in Down's syndrome: a biological marker of a neuroimmune deficit

To test the hypothesis of an altered central nervous system influence upon the immune system of Down's syndrome (DS) patients and in order to establish a peripheral biological marker of neuroimmune deficit, we have studied the characteristics of the beta 2-adrenergic receptor (B2AR) system in peripheral blood monocytes (PBMC) of 12 pre-pubertal (six boys and six girls) individuals and correlated alterations in binding with changes in distribution of lymphocyte subsets. Using the very potent beta-adrenergic antagonist, iodocyanopindolol ([125I]CYP), as a ligand, the present study shows that a typical BAR population of the beta 2-subtype is present in PBMC from DS children, with binding kinetics and structural specificity similar to those measured in PBMC from patients with other (non-genetic) forms of mental retardation, or in PBMC from age-matched healthy subjects. On the other hand, this study revealed a significant increase in B2AR binding capacity of PBMC from DS subjects (Bmax = 5258 +/- 470 sites/cell) compared to the values measured in the control population of retarded children (Bmax = 1965 +/- 280 sites/cell), characterized by an approximately three-fold increase in the Bmax, without changes in binding affinity (KD = 40.5 +/- 2.0 and 36.6 +/- 2.5 pM in DS and retarded patients, respectively). The flowcytometric analysis of lymphocyte subsets using a panel of monoclonal antibodies against a series of lymphocyte markers revealed a profound alteration in the distribution of lymphocyte subtypes with an almost 50% decrease in B cell and T-helper populations, a three-fold increase in T-cytotoxic suppressor, a seven-fold increase in lymphocyte-activated killer cells (LAK) and 30% increase in natural killer (NK) subpopulations. When fluorescence-labelled lymphocytes were visualized in the cytofluorograph and sorted for their use in the radioreceptor assay, B cells had approximately twice the number of B2AR when compared to T cells; and cytotoxic/suppressor showed a higher binding capacity compared to T-helper cells. On the other hand, labelled lymphocytes from DS patients showed a specific increase in receptor number in B cells, T-cytotoxic suppressor and NK subpopulations. It is concluded that a profound catecholaminergic dysfunction not previously appreciated in DS is reflected by a significant alteration in lymphocyte subset distribution and by a specific up-regulation of lymphocyte B2AR in phenotypically and functionally distinct T and B cells as well NK subpopulations, suggesting a possible denervation supersensitivity phenomenon.(ABSTRACT TRUNCATED AT 400 WORDS)

Flow cytometric analysis of whole blood lysis, three anticoagulants, and five cell preparations

We studied the effects of anticoagulants and cell preparation methods on lymphocyte forward-angle scatter (FSC), autofluorescence, and immunofluorescent staining for CD45, CD14, and CD13. Blood samples collected in ethylenediaminetetracetic acid (EDTA), heparin, and acid citrate dextrose (ACD) were processed by using conventional Hypaque-Ficoll (HF) separation and four whole blood (WB) lysis techniques: Immuno-lyse, Q-Prep, FACS Lyse, and Gen Trak Lysis. Lymphocytes prepared by using three of the four whole blood methods gave FCS values comparable to those isolated by HF, while one method (FACS Lyse) gave consistently lower values. Autofluorescence values were comparable by all methods except Immuno-lyse, which showed consistently higher values in blood stored for 24 h with any anticoagulant. Immunofluorescent values for CD45-stained cells were quite consistent across all methods, and among the whole blood methods, FACS Lyse and Q-Prep uniformly gave the highest purity of CD45-positive cells in the lymphocyte light scatter gates. Additionally, propidium iodide (PI) analyses of CD45-stained whole blood, and analyzed without lysis, confirmed that ACD and heparin were superior to EDTA for maintaining viable leucocytes overnight. Future studies should focus on other commonly used reagents, a wide variety of abnormal samples, and cell viability.

Changes in leukocyte subpopulations following total hip replacement surgery. Effects of high doses of corticosteroids

Changes in leukocyte subpopulations and the effects of high-dose corticosteroids (HDC) on these changes were studied in patients undergoing total hip replacement surgery. Twelve patients were randomly divided into a non-steroid (n = 6) and a steroid group (n = 6). The steroid patient group was treated with HDC. In the non-steroid group, we found a leukocytosis, monocytosis, lymphocytopenia and granulocytosis after surgery in local anaesthesia. Only the changes in granulocyte counts were significant. Furthermore, the relative proportion of pan T-cells, helper/inducer T-cells, suppressor/cytotoxic T-cells, B-cells, activated T-cells and natural killer-cell subset did not change significantly during the post-operative course. Thus, lymphocytopenia was caused by reduced absolute counts of all these subsets. However, there was a tendency for decreased relative proportions of pan T-cells, inducer/helper T-cells, activated T-cells and natural killer (NK) cell subset in the early postoperative phase. Treatment with HDC significantly raised the numbers of leukocytes and granulocytes and decreased the lymphocyte and monocyte counts in the first 2 days after surgery, accounting for significant differences between the two patients groups. The percentage of pan T-lymphocytes was significantly lower in the steroid patient group on days 1 and 2 after the operation. There was no significant difference between the two patient groups with regard to the percentages of B-lymphocytes, T-lymphocyte subsets, NK cell subset, leu M3 cells and helper:suppressor ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Circulating tumor necrosis factor, interleukin-1 and interleukin-6 concentrations in chronic alcoholic patients

Although altered cytokine homeostasis has been implicated in the pathogenesis of alcoholic liver disease, the relationship between cytokines and metabolic consequences of alcoholic liver disease is unknown. We, therefore, sought to correlate circulating concentrations of tumor necrosis factor-alpha, interleukin-1 and interleukin-6 to clinical and biochemical parameters of liver disease in chronic alcoholic patients. We used an enzyme-linked immunosorbent assay to measure plasma tumor necrosis factor and interleukin-1 and a bioassay to measure serum interleukin-6 in three groups of alcoholic men as follows: (a) actively drinking alcoholic men without evidence of chronic liver disease, (b) nondrinking alcoholic men with stable cirrhosis and (c) patients with acute alcoholic hepatitis. Mean cytokine concentrations were elevated in cirrhotic patients and alcoholic hepatitis patients compared with controls and alcoholic patients without liver disease. Tumor necrosis factor-alpha and interleukin-1 alpha concentrations remained elevated for up to 6 mo after diagnosis of alcoholic hepatitis, whereas interleukin-6 normalized in parallel with clinical recovery. Concentrations of all three cytokines were correlated with biochemical parameters of liver injury and hepatic protein synthesis plus serum immunoglobulin concentrations. We could not demonstrate a relationship between cytokine concentrations and peripheral endotoxemia. Percentages of peripheral blood monocytes that reacted with monoclonal antibodies to CD25 (interleukin-2 receptor) and human lymphocyte antigen-DR were similar for alcoholic patients and controls. These data suggest that tumor necrosis factor-alpha and interleukin-1 alpha are related to some of the metabolic consequences of both acute and chronic alcohol-induced liver disease, whereas interleukin-6 is related to abnormalities seen in acute liver injury.

Two-layer gradient separation of granulocytes for functional tests

Two gradient separation techniques were compared with the dextran sedimentation method for the separation of granulocytes from blood. Both techniques gave adequate yield and excellent purity, and flow cytometric analysis of surface membrane markers gave no indication of subset selection during the procedure. Cells separated by the three methods behaved comparably in functional tests including random migration, chemotaxis and chemiluminescence. The gradient separation techniques are rapid and efficient methods for the preparation of near 100% pure granulocyte suspensions for functional studies.

Human epidermal T cells predominantly belong to the lineage expressing alpha/beta T cell receptor

The epidermis of clinically normal-appearing human skin harbors a phenotypically heterogeneous population of T lymphocytes (TCs), the majority of which are CD2+/CD3+/CD5+ "memory" cells, but in an unactivated state, and express the TCR-alpha/beta. In contrast to murine skin, only a very minor subpopulation of CD3+ cells in the human epidermis bears the TCR-gamma/delta. Epidermal TCs primarily are distributed along the rete ridges in the basal keratinocyte layer and are often in close apposition to Langerhans cells (LCs). These TCs were propagated from epidermal cell suspensions after stimulation with TC activating agents (Con A, rIL-1, rIL-2), then evaluated for phenotypic features and TCR diversity. Similar to the in situ situation, most were CD4-/CD8+/TCR-alpha/beta+. In addition, two cultures contained TCR-gamma/delta+ cells; one of these determined to be an adherent CD4-/CD8+ population. Epidermal TCs were significantly (p less than 0.0001) more abundant in the sole than in the other body regions examined (i.e., 40 vs. 7 CD3+ cells/linear centimeter of epidermis) and seemed to have a particular affinity for the acrosyringial epithelium of eccrine sweat ducts. Moreover, the sole usually contained a greater number of CD8+ relative to CD4+ TCs, whereas the epidermal CD4/CD8 ratio in the trunk and extremities was quite variable, although the trend also was towards a slightly larger percentage of CD8+ cells. Collectively, our data suggest that the volar epidermis has a unique microenvironment which is responsible for both the higher density of TCs, preferentially CD8+, and lower number of LCs. This study has not only provided evidence for significant regional variability in the human epidermal TC population of normal skin, but also strengthens the concept for skin-associated lymphoid tissues (SALT), whereby memory TCs recirculate back to the epidermis and interact with resident antigen-presenting cells (i.e., LC).

A rapid technique for lymphocyte preparation prior to two-color immunofluorescence analysis of lymphocyte subsets using flow cytometry. Comparison with density gradient separation

A technique is described for lymphocyte preparation which permits analyses by two-color immunofluorescence and flow cytometry. It consists, briefly, of the lysis of red blood cells and washing of white blood cells prior to labeling. We tested this technique with a large panel of monoclonal antibodies in mono- and dual immunofluorescence. By comparing these results to those obtained after density gradient separation, we found the following statistically significant differences: the count of the phenotype B1+ was higher after whole blood lysis preparation than after density gradient separation; whereas, the corresponding counts of OKT4+ and Leu-4-Leu-7+ phenotypes were lower. No difference was detected with OKT8+, Leu-4+, OKT8+Leu-4+, OKT8+Leu-4-, OKT8-Leu-4+, OKT8+Leu-7+, Leu-4+Leu-7+, Leu-4-Leu-11c+, OKT8+Leu-11c+ and OKT8+Leu-15+ phenotypes. We have studied the reproducibility of both methods and the correlation between them. The disparity of the lymphocyte subset count between these two methods, though statistically significant, was relatively weak and seems to be due to the density gradient separation. Since the preparation of lymphocytes using the density gradient method is time consuming, we propose whole blood lysis as an alternative lymphocyte separation method when assessing immune status in human disease by flow cytometry. It offers the following advantages: (i) it does not require additional steps, (ii) it permits two-color immunofluorescence through the labeling of white blood cells after washing, (iii) it is reliable, (iv) it is reproducible, and (v) it is helpful in studies of lymphopenia since it offers the possibility of lymphocyte enrichment.

[Flow cytometry in immunology and hematology: some essential practical aspects]

Flow cytometry, supported by monoclonal antibodies, has widely contributed in the cellular identification, notably in the clinical and haematological fields. This technique has found several applications since the qualitative phenotyping and the quantitative analysis of the immune system's cell populations are helpful in the diagnosis and the therapy. Besides, these indications require an appropriate knowledge of several methodological aspects including factors related to the sample donor: age and sex; sampling: time and quantity; and the sample preparation conditions. References values, needed for the results interpretation, have a meaning only if they are defined within these validity limits. Previous trials have been done in order to define a biological value representative of the immunological status, such as the CD4/CD8 ratio. Unfortunately this ratio is not justified in the scope of new knowledge concerning the cellular interactions and the functional heterogeneity of cells involved in the immune system.