Lymphocyte subsets in the blood: a diagnostic window on the lymphoid system?

Age-related increase of CD45RO+ lymphocytes in physically active adults

The CD45RO phenotype of peripheral blood CD4+ and CD8+ lymphocytes were determined in physically active males (n = 171) and females (n = 70) ranging in age from 15-68 years. Direct immunofluorescence and dual color flow cytometry was performed for analysis. Absolute cell numbers (r = 0.473) and percentages of CD4+ CD45RO+ (r = 0.648) within the CD4+ population, percentage of CD8+ CD45RO+ cells within the CD8+ lymphocytes (r = 0.498) and total lymphocyte number (r = -0.242) correlated significantly (p < 0.001) with age. We conclude that the age-related increase of CD45RO+ T cells indicates a gradual increase of activated T cells.

Blood B, T, CD4+ and CD8+ lymphocytes in female Wistar rats

We have established reference values of peripheral blood lymphocyte subsets in healthy female Wistar rats under highly standardized conditions. Using monoclonal antibodies and flow cytometry, T lymphocytes (OX19+), B lymphocytes (OX6+ and anti-Ig+), T-helper/inducer (W3/25+), and T-suppressor/cytotoxic subsets (OX8+) were determined, from week 11 to week 21 after birth. The mean percentages of T and B lymphocytes with respect to total lymphocytes were 78.5% and 18%, respectively; the mean percentages of T-helper/inducer and T-suppressor/cytotoxic cells in relation to T lymphocytes were 59% and 25%, respectively (n = 48). No difference in total leukocyte count, differential leukocyte analysis, or lymphocyte subsets was observed during the 10 weeks the rats were studied under standard housing conditions. Therefore, the period considered seems the most appropriate in which to carry out experiments that could involve lymphocyte subset disturbances.

Effect of red cell lysis protocols on the expression of rat peripheral blood lymphocyte subset and activation antigens

The effect of ammonium chloride and a commercial red cell lysing agent (Erythrolyse) on cell subset (CD4, CD8, B cell common leucocyte antigen) and activation (p55IL-2R [OX39], MHC class II) antigen expression by freshly isolated and in vitro activated rat peripheral blood lymphocytes was compared. Freshly isolated cells treated with the commercial lysing agent Erythrolyse were 42 +/- 12% p55IL-2R+, whereas p55IL-2R expression was not detected following red cell lysis with ammonium chloride. The expression of cell subset and MHC class II antigens was unaffected by either of the treatment protocols. Density gradient separation of freshly isolated cells had variable effects on antigen expression. In some cases up to a two-fold increase in p55IL-2R expression was observed, whilst in others there was a reduced receptor expression. Similarly, MHC class II antigen expression was either increased or reduced following density gradient separation. IL-2R expression on cells activated in vitro with the mitogen concanavalin A (95 +/- 2% IL-2R+) was unaffected by ammonium chloride lysis. Incubation of freshly isolated lymphocytes with p55IL-2R antibody prior to ammonium chloride treatment did not prevent the reduction in receptor expression. These findings suggest that ammonium chloride lysis of freshly isolated rat peripheral blood prior to IL-2R expression analysis should be avoided.

Decline in the CD4+ lymphocyte population in the blood of SIV-infected macaques is not reflected in lymph nodes

Although loss of CD4+ lymphocytes in peripheral blood is a standard criterion for evaluating the course of HIV disease, little is known about changes within lymphoid organs, which contain the bulk (> 50%) of the body's lymphocytes. Because such studies are feasible only by using non-human primates, we have examined lymph nodes (LNs), spleen, and blood from monkeys infected with two isolates of simian immunodeficiency virus (SIV). During both the acute and chronic phases of these infections, characteristic reductions in the blood CD4+ cell levels are not reflected in LN, where the CD4+ pool remains within normal levels. However, when circulating CD4/CD8 ratios have consistently fallen to approximately 0.5, striking decreases in the percentage of CD4 cells (CD4%) and CD4/CD8 ratios in LN occur concomitantly with dramatic increases in viral antigen expression on follicular dendritic cells within LN germinal centers (GCs). The data suggest that loss from the total T cell pool in minimal until the final stages of SIV and HIV disease and that the immunological deterioration of LN is the event that precipitates the increased susceptibility to infections and progression to AIDS.

In vivo persistence of expanded clones specific for bacterial antigens within the human T cell receptor alpha/beta CD4-8- subset

We analyzed the T cell receptor (TCR) rearrangements of 100 TCR-alpha/beta CD4-CD8- (double negative [DN]) T cell clones from normal individuals. We found that in four out of six donors this subset contains expanded clones that often account for 0.5% and, in one individual, even 7% of all peripheral blood lymphocytes. By combining limiting dilution analysis and N region oligotyping of polymerase chain reaction amplified TCR cDNA, we could measure the clonal size and show that two of these expanded clones remain stable in size for up to 4 yr in peripheral blood. The expanded clones analyzed ex vivo are not cycling and CD45 RAhi ROlo, but express high levels of alpha 4/beta 1 integrins, suggesting that they may have reverted to resting cells after activation. One of these expanded DN clones proliferates in vitro in response to Escherichia coli presented by monocytes cultured in GM-CSF plus IL-4 and kills CD1a+ Molt-4 cells. In contrast to what was found in the alpha/beta DN subset, alpha/beta CD4+ T cell clones specific for a tetanus toxin epitope showed a very small clonal size (< 1 in 10(7)) and could not be reisolated after 2 yr. Taken together, these results indicate that large clonal size and persistence are distinctive features of alpha/beta DN cells specific for bacterial antigens. These cells may use antigen-presenting cells, restriction molecules, and selection routes different from those used by antigen-specific CD4+ T cells.

Modalities of in vitro IgM and IgG production by peripheral blood lymphocytes of chronic lymphocytic leukemia patients and healthy volunteers

In vitro spontaneous and mitogen (LPS, rIFN alpha and PWM) or cytokine (rIL-2) induced IgM and IgG production by peripheral blood lymphocytes of 15 CLL patients and 16 healthy volunteers has been determined. This study has shown: (1) that there is no difference between healthy donors and CLL patients in respect to level and variability of spontaneous immunoglobulin production by their lymphocyte cultures; (2) that there is no correlation between the percentage of B cells in individual cell cultures obtained from CLL patients and the amount of spontaneously produced IgM or IgG; (3) that there is a correlation between spontaneous in vitro IgM production and IgM content in the serum of the patient; (4) that in CLL patients selective augmentation of IgM production could be obtained after stimulation with PWM or rIL-2, but only in those cultures which spontaneously produce more than 35 ng/ml of IgM and (5) that the number of lymphocyte cultures able to be stimulated to IgM production is about 10 times smaller when they originate from CLL patients than from healthy volunteers. These findings are in line with the view that B cells in CLL patients often do not differentiate due to the insufficiency of factor(s) secreted by their own activated T-cells, but that in essence they follow the same differentiation pathway as normal B-cells.

Theophylline--an immunomodulatory role in asthma?

Theophylline, a drug used for the treatment of asthma, is recognized as an immunomodulator affecting T-lymphocytes both in vitro and in vivo. The effect of slow-release theophylline (Uniphyllin Continus) on the late asthmatic response (LAR) has been compared with placebo before and after 5 wk of treatment in a double-blind, randomized, parallel group study. Nineteen volunteers with stable mild asthma successfully completed the study. All were dual responders with a documented late response to inhaled house dust mite extract. The LAR was assessed both in terms of changes in lung function and in peripheral blood T-lymphocyte subsets. The mean (SEM) maximal late fall in FEV1 before and after treatment was 28.8 (4.1)% and 7.8 (2.0)% with theophylline, versus 35.8 (5.1)% and 29.1 (5.0)% with placebo (p = 0.046; Cl, 0.3-26.9). Corresponding figures for specific airway conductance (SGaw) were 46.4 (8.4)% and 7.2 (8.0)% with theophylline versus 46.2 (7.2)% and 44.8 (7.7)% with placebo (p = 0.008; Cl, 11.2 to 64.1). This was achieved at a mean (SD) trough serum theophylline level of only 7.8 (3.5) micrograms/ml. Airway responsiveness to methacholine was not significantly changed 24 h after the initial allergen challenge. There was a trend towards a decrease in baseline responsiveness after treatment with theophylline compared with that after placebo (p = 0.07). Studies of peripheral blood lymphocytes showed a modifying effect of treatment on the allergen-induced changes in CD4 and CD8 counts 48 h after challenge. Previous studies have shown a protective effect of theophylline on the LAR at serum theophylline concentrations within the conventional range for bronchodilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Phenotypic analysis of cells in bronchoalveolar lavage fluid and peripheral blood of maedi visna-infected sheep

A phenotypic analysis of bronchoalveolar lavage fluid (BALF) and peripheral blood (PB) cells in maedi visna virus (MVV)-infected sheep has been performed. The differential cell count in BALF from MVV-infected animals was characterized by a significant increase (P < 0.05) in lymphocytes and neutrophils. Lymphocyte phenotyping in BALF from MVV-infected sheep showed a significant decrease (P < 0.05) of CD4+ cells, a significant increase (P < 0.05) of CD8+ cells and a significant inversion (P < 0.001) of the CD4+/CD8+ ratio. CD5+ lymphocytes were also significantly decreased (P < 0.05). Gamma delta T cells and B cells did not differ significantly when compared with the controls. No correlation was observed between BALF and PB lymphocyte phenotypes. BALF macrophages from MVV-infected animals showed increased MHC class II expression and BALF lymphocytes from the same animals demonstrated up-regulation of LFA-1 and LFA-3 expression. These findings and their relationship with lentiviral pathogenesis are discussed.

Analysis of peripheral blood mononuclear cells in rodents by three-colour flow cytometry using a small-volume lysed whole blood technique

Techniques were adapted to permit phenotypic analysis of peripheral blood leucocytes in rats and mice using small volumes of lysed whole blood and single, dual- or triple-colour immunofluorescence staining with flow cytometry. Red cell lysis using proprietary lysing solutions provides populations of lymphocytes, monocytes and granulocytes clearly differentiable by their light scatter properties. In the present study, measurement of functional and activation T lymphocyte subsets was performed by single- and dual-colour flow cytometry in both species and in excess of 5000 lymphocytes could be counted using as little as 10 microliters of whole blood. Triple-colour fluorescence, using antibodies labelled with fluorescein, phycoerythrin and biotin permitted simultaneous detection of three phenotypic markers. This novel technique has two major advantages, maximising the phenotypic information which may be obtained and using volumes of blood which are sufficiently small that they can be drawn regularly from the same animal.

In situ hybridisation for cytokine gene transcripts in the solid tumour microenvironment

To determine if mononuclear cells (MNC) infiltrating various types of human solid tumours express genes for cytokines, in situ hybridisation with 35S-labelled cDNA antisense probes for interleukin 2 (IL2), interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), interleukin 1-beta (IL1-beta), transforming growth factor beta (TGF-beta) and interleukin 2-receptors (IL2R) was performed. Fresh-frozen tissue samples of ovarian carcinomas (n = 13), breast carcinomas (n = 12), and squamous cell carcinomas of the head and neck (SCCHN, n = 7) were evaluated for the presence and localization in the tumour of MNC positive for cytokine genes. In ovarian tumours and those breast carcinomas producing little or no mucin, only rare positive MNC were observed. In contrast, breast carcinomas producing mucin and all SCCHN contained numerous MNC expressing gene transcripts for IL2, IFN-gamma, TNF-alpha, IL2R as well as TGF-beta. In tumour-involved lymph nodes of patients with SCCHN, MNC expressing genes for cytokines were found around tumour metastases but not in non-involved areas. These data suggest that tumours expressing immunogenic antigens (e.g. mucin) contain many activated MNC, while other tumours either fail to activate or suppress functions of infiltrating MNC. In SCCHN or tumour-draining lymph nodes, local down-regulation of antitumour responses might be mediated by TGF-beta produced by activated tumour-infiltrating MNC.

Changing patterns of the IL-2/IL-2R pathway of lymphocyte activation following exposure to Plasmodium falciparum products: a study with squirrel monkey peripheral blood mononuclear cells

Squirrel monkeys are experimental hosts useful for studies on human malaria. In the present work, in vitro lymphocyte reactivity was measured by proliferation in the presence of Plasmodium falciparum-derived products, and found to depend on the previous malarial status of the animals and upon the source and/or the nature of the P. falciparum-derived material. Special attention was given to the IL-2/IL-2R pathway of lymphocyte activation. Culture supernatant from P. falciparum-parasitized erythrocytes exerted an inhibitory effect towards T lymphocytes obtained from P. falciparum-non-immune squirrel monkeys, when activated, for instance, by PHA. These lymphocytes did not incorporate tritiated thymidine (neither they did proliferate) although they expressed IL-2 alpha and beta binding chains and secreted IL-2 (or at least TCGF). This inhibitory effect could not be rescued by the addition of rhIL-2, although the assayed lymphocytes could retain the ability to continue their cell cycle progression and divide after removal of the P. falciparum-derived inhibitory product(s). The incidence of anti-mitogenic molecules which impair the IL-2/IL-2R pathway of lymphocyte activation in malaria related processes is discussed.

Autoimmune hypothesis in narcolepsy

Since the discovery of an almost 100% association of HLA-DR2 with narcolepsy-cataplexy, many efforts have been made to demonstrate the intervention of immune factors in the pathogeny of the disease. Some epidemiological features could support this hypothesis: age of onset around 25, triggering factors, association with multiple sclerosis. Molecular studies at the DNA level have, up to now, failed to uncover an abnormal gene in the HLA system, which would imply that the DR2 antigen acts through its role in the immune response. However, results have been largely inconclusive as far as classical features of autoimmunity in blood and CSF are concerned. In canine narcolepsy, a linkage with a human immunoglobulin-related gene has recently been shown, and may constitute a counterpart of the HLA association in man. Thus, the hypothesis of a transient and discrete autoimmune aggression may be ruled out.

Contrasting effect of delta-9-tetrahydrocannabinol on IL-2 activity in spleen and lymph node cells of mice of different ages

The purpose of this study was to investigate the immunomodulatory effect of delta-9-tetrahydrocannabinol (THC) on spleen and lymph node cells of adult and young mice. When plant mitogen (Con A or PHA) stimulated cells were treated with varying doses of THC, the proliferation of spleen and lymph node cells of adult and young mice was suppressed. This suppression was found to be compatible with a decrease in number of Tac positive cells as well as a down-regulation of IL-2 activity. In contrast, when these cells were stimulated with anti-CD3 antibody in combination with THC, the pattern of the immunomodulation as well as the absolute effects of the drug differed with the age of the mice as well as the organ of origin of the cells. In this regard, anti-CD3 antibody stimulation in combination with low doses of THC stimulated proliferation of splenocytes obtained from adult mice. The stimulation was found to reflect an increase in the number of both suppressor/cytotoxic T cells (Ly2 cells) as well as Tac positive cells. IL-2 activity was found to be enhanced under these conditions. This up-regulation of responsiveness was not seen in either lymph node cells of adult or young mice or in spleen cells of young mice. The THC modulating activity is directly related to its effect on both IL-2 activity and generation of Tac positive cells in spleen and lymph node cells of both adult and young mice. It appears, therefore, that not only age, but also lymphoid organ system differences are important factors in terms of considering the effects of drugs of abuse.

Reactivity of some monoclonal antibodies specific for human lymphocytes with vervet monkey peripheral blood mononuclear cells

Reactivities of some monoclonal antibodies to human lymphocyte surface antigens were tested on vervet monkey peripheral blood mononuclear cells (PBMC), using flow cytometry and immunoperoxidase techniques. A number of antibodies were identified which reacted with similar populations of lymphocytes from vervet monkeys. These included antibodies that define T cells, suppressor/cytotoxic cell subset, pan B cells, monocytes and MHC class I and II. A number of anti-CD4 markers examined were unsuitable for use in the vervet system.

Influence of circadian light-dark alternations on macrophages and lymphocytes of CBA mouse

The influence of circadian 12 h light-12 h dark alternations on CBA mouse macrophages and lymphocytes was determined using tests for macrophage spreading and ingestion ability or flow cytometry immunophenotyping of blood, lymph node, and spleen lymphocytes. The animals were tested every 4 h around the clock. Collected macrophages were incubated in vitro for 3 or 18 h. Monoclonal antibodies permitted detection of T-lymphocytes, suppressor-cytotoxic T-lymphocytes, helper-inducer T-lymphocytes, or B-lymphocytes. Two types of analyses were performed: First, the difference between the same intervals of the 12 h light or dark period was determined. The macrophage ingestion was significantly lower at the beginning and higher at the end of the dark period. We have also found a significant increase in blood T-lymphocytes of helper-inducer T-lymphocyte percentages and of the T helper-inducer: T suppressor-cytotoxic ratio during the dark period. Second, the ultradian variation during the 12 h light or dark period was determined. The variability was significant both for macrophage spreading and ingestion. Multiple significant variations of lymph node, spleen, or blood lymphocyte percentages were also observed. All of these data indicate that daily alteration of the lighting regimen significantly influences mouse peritoneal macrophage functions and various lymphocyte subsets.

Random entry of circulating lymphocyte subsets into peripheral lymph nodes and Peyer's patches: no evidence in vivo of a tissue-specific migration of B and T lymphocytes at the level of high endothelial venules

Lymphocytes continuously migrate through the body and thus immune competent cells are constantly delivered to most tissues. They interact with high endothelial venules (HEV) via specific homing receptors and vascular addressins, and these molecules seem to be the reason for a preferential homing of B lymphocytes into Peyer's patches and of T lymphocytes into peripheral lymph nodes. When lymphocytes derived from lymph node cell suspensions were applied in the in vitro lymphocyte/endothelium binding assay, the well-known preference of mouse lymph node B lymphocytes for Peyer's patch HEV compared to peripheral lymph node HEV was confirmed in the rat (2.8 times). When in the same in vitro assay thoracic duct lymphocytes (TDL) were used this preference was far less obvious (1.4 times). However, by injecting rat TDL intravenously and by tracing them directly in HEV, B, T, CD4+ and CD8+ lymphocytes are seen to enter Peyer's patches and peripheral lymph nodes in vivo without preference. Thus, in contrast to lymphocytes from lymph node cell suspensions, no evidence was found of a tissue-specific migration of thoracic duct B, T, CD4+ and CD8+ lymphocytes at the HEV level. This finding demonstrates the importance of considering both experimental conditions and the cell source used when investigating lymphocyte traffic.

Splenic autotransplantation provides protection against fatal sepsis in young but not in old rats

Splenectomy increases the risk of contracting infections with high mortality. Thus, splenic tissue should be repaired orthotopically whenever possible. If all attempts fail, splenic autotransplantation might be a suitable method for splenic salvage. The protective function of such transplants in adults has been questioned, leading to a decreased frequency of splenic autotransplantations. However, the regeneration of splenic tissue is better in the young organism than in the old, suggesting that the protection provided by regenerated splenic tissue might be more reliable in children than in adults. In addition, children are at a higher risk in the case of overwhelming postsplenectomy sepsis. The protection warranted by regenerated splenic tissue after autotransplantation at different ages was examined using a highly standardized animal model. Sham operation, splenectomy, and splenic autotransplantation were performed on adult, weanling, and newborn rats, and Streptococcus pneumoniae was applied intranasally 9 months after the operation. After pneumococcal challenge about 80% of the splenectomized animals in the different age groups died of infection, whereas only 20% of the sham operated rats died. Regenerated splenic tissue resulting from splenic autotransplantation performed on adult or weanling rats demonstrated no protective function. However, in newborn rats with transplanted splenic tissue, both survival rate and survival time were increased significantly. Determination of lymphocyte subsets in the blood did not allow the protective role of splenic transplants to be predicted. This study indicates that disappointing results of splenic autotransplantation in adult patients should not lead to false pessimism about the role of this operation in children.

From pathology to physiology of the human T-lymphocyte receptor

The recent description of a selective human CD3 gamma deficiency and other T-cell receptor (TCR)/CD3 structural and functional defects, together with previous biochemical data on the structure and interactions of the TCR/CD3 complex, may aid in elucidating the physiology of this multi-subunit membrane ensemble. CD3 gamma seemed to be required for the commitment and thymic maturation of an important fraction of T lymphocytes to the CD8 (but not CD4) lineage, perhaps by participating with the CD8 co-receptor in the instructive signal delivered through the alpha beta TCR during intrathymic positive selection by HLA class I molecules. The homologous CD3 delta component would, in contrast, be necessary for the selection of CD4 lymphocytes by HLA class II molecules. The interaction of CD4 and CD8 with the TCR/CD3 complex during antigen recognition may thus be asymmetrical, taking place through CD3 delta and gamma, respectively. Also, the existence of in vivo functional TCR/CD3 hemireceptors (lacking either CD3 gamma or CD3 delta) is suggested, and defects in their relative amount on the T-cell surface may disrupt unresponsiveness to self antigens and generate autoimmunity.

Modulation of human lymphocyte marker expression by gamma irradiation and mitomycin C

gamma irradiation (GR) or mitomycin C (MC) treatment of stimulator cells is frequently used to achieve unidirectionality of response in the mixed lymphocyte reaction. As GR differs from MC in the pathways used to block lymphocyte replication, this study analyzes the effects of these modalities upon the expression of various differentiation and Class II major histocompatibility antigens on lymphocytes cultured for 24, 48, and 72 hr. There was a decrease in the mean density of HLA-DR expression on CD3+ and on CD8+ cells at 24, 48, and 72 hr after exposure to GR (42 and 35, 60 and 69, and 26 and 49%, respectively) or to MC (26 and 11, 26 and 18, and 46 and 30%, respectively). There was a parallel decrease in the levels of the corresponding cell subsets when compared with control cultured cells not exposed to GR or MC. In contrast, the density of HLA-DR markers on CD3-negative cells was increased at 24, 48, and 72 hr of culture following exposure to GR (73, 82, and 102%, respectively) or to MC (9, 45, and 80%, respectively). There was a more profound decrease in CD3+, CD8+, and CD19+ cell subset levels and in the density of the corresponding markers in GR-treated cells than in those of cells exposed to MC when the results were compared with those of untreated cultured control cells. Although GR appears to exert a more profound effect than MC, the results indicate that both modalities have the capacity to reduce the density of polymorphic determinants on Class II (HLA-D region)-encoded molecules on T (CD3+ and CD8+) and B (CD19+) cells which are known to trigger potent MLR responses. Both modalities may therefore affect profoundly the relative strength of MLC responses and the derived measurements of the degree of HLA Class II compatibility between stimulator and responder cells.

Detection of cytokine receptors by high-sensitivity immunofluorescence/flow cytometry

Cytokines have profound effects on cells, and act through receptors which need only be at low concentrations (around 100 copies per cell) to transmit activation signals. The detection of such low concentrations is possible using monoclonal antibodies and fluorescence/flow cytometry, but only by using specialized techniques. The best results so far have been obtained using biotinylated second antibody followed by phycoerythrin-streptavidin, and batches of these reagents have to be carefully selected. Analysis of the fluorescence is best done using 546 nm excitation from a mercury arc lamp, but 512 nm excitation from an argon-ion laser can also be used. With appropriate alignment, instruments with 488 nm fixed-wavelength lasers can give sensitivity almost as good as the 546 nm system. Working at high sensitivity, background levels also increase, particularly for B lymphocytes. Background staining can be reduced to acceptable levels by blocking the two major mechanisms for non-specific binding. Applications of these methods to the detection of cytokine receptors on normal and malignant cells are reviewed.

Limiting-dilution analysis of T cell reactivity to mycobacterial antigens in peripheral blood and synovium from rheumatoid arthritis patients

Limiting-dilution analysis (LDA) was used to quantify the frequency of Mycobacterium bovis BCG- and 65-kD-reactive T cells in paired samples of peripheral blood and synovial tissue from patients with rheumatoid arthritis. The frequency of BCG-reactive T cells detected in the peripheral blood of patients ranged from 1/585 to 1/7639 versus a control frequency range of 1/480 to 1/6773. The frequency of such cells in the synovium was found to be much lower than it was in peripheral blood; in fact, in 80% of patients synovial BCG-reactive T cells were not detected. The frequency of 65-kD-reactive cells in the peripheral blood of each individual was lower than the frequency of BCG-reactive cells (range 1/3738 to 1/55,324), as would be expected. However, no synovial 65-kD-reactive cells were detected from any of the patients studied. The LDA assay for the 65-kD antigen was consistent with the single hit model, that for BCG was not. The relatively high proportion of mycobacterial-reactive precursors seen in the peripheral blood of non-vaccinated individuals may reflect a population of cells induced either by natural environmental exposure to mycobacteria or, given the highly conserved nature of heat shock proteins across phylogeny, by some other infection. The results also suggest that the frequent finding of reactivity to proteins such as the 65-kD heat shock protein contained within BCG may not be a generalized phenomenon in rheumatoid synovium.

Autoantibodies to CD45 in systemic lupus erythematosus

Autoantibodies to surface antigens on lymphocytes and other cells of the immune system may contribute to the development of immunoregulatory and other cellular immune abnormalities in patients with active systemic lupus erythematosus. Of special interest in this respect are autoantibodies to CD45 (leukocyte-common antigen, T200), a plasma membrane protein tyrosine phosphatase implicated in the regulation of lymphocyte functional activity, including cytotoxicity, proliferation, and differentiation.

The role of lymphocyte production and migration in the lymphopenia caused by 2-acetyl-4-tetrahydroxybutyl imidazole

2-Acetyl-4-tetrahydroxybutyl imidazole (THI), a component of the food colouring ammonia caramel, has been shown to produce a profound and rapid lymphopenia in peripheral blood in the rat. In order to investigate whether the cause of the lymphopenia was due to the reduced production and influx in the circulation, redistribution of lymphocytes into other lymphoid compartments or an increased cell death, THI (1 mg/kg/day) was given in the drinking water for up to 14 days to F344 rats. A profound depletion of lymphocytes after already 1 day was only found in the blood compartment, whereas no such marked and rapid changes were found in the cellularity of other lymphoid compartments. The proportion and absolute number of DNA-synthesizing cells in each lymphoid organ was quantified using an antibody directed against incorporated 5-bromo-2'-deoxyuridine (BrdU), 1 h after a single BrdU injection. Additionally, enumeration and localization of BrdU+ cells was determined at later time points after a single BrdU injection by flow cytometry and immunocytochemistry, in order to examine the distribution and localization of recently formed (BrdU+) lymphocytes. THI treatment had no effect on the proliferation rate and the distribution of newly formed (BrdU+) cells in the lymphoid organs. However, migration studies revealed that THI treatment resulted in an increased percentage of fluorescein-labelled peripheral blood lymphocytes found in the spleen and bone marrow and a decreased percentage in the cervical and mesenteric lymph nodes, 24 h after injection. Collectively these results indicate that the lymphopenia in the peripheral blood compartment after THI treatment, is caused by a rapid sequestration of lymphocytes into the spleen and bone marrow rather than by a reduced lymphocyte production and release into the periphery. The fact that THI also caused lymphopenia in splenectomized rats, indicates that the spleen does not play an active part in the change in migrational behaviour of lymphocytes after THI treatment. Finally, as there was no increase in the absolute number of lymphocytes found in the spleen or bone marrow it seems they are rapidly degraded.

Nonsegmental vitiligo: decrease of the CD45RA+ T-cell subset and evidence for peripheral T-cell activation

Peripheral T-lymphocytes from 16 randomly selected patients with nonsegmental vitiligo were labeled with monoclonal antibodies recognizing T-cell receptor (TCR) alpha/beta, TCR gamma/delta, CD3, CD4, CD8, CD45RA, CD45RO, CD11b, CD11c, CD16, CD56, CD25, CD54, and HLA-DR antigens. In comparison with matched controls, a significant decrease of the CD45RA+ subset (P less than 0.03) together with significant increase of the circulating HLA-DR+ cells (P less than 0.02) was found. No other alterations were detected. These findings may point to some autoimmune phenomena involved in the pathogenesis of the disease. The increased HLA-DR expression indicates the presence of activated peripheral T-cells. Thus, our data provide new and further evidence for T-cell dysregulation in nonsegmental vitiligo.

Effects of anaesthesia and surgery on the immune response

Alterations have been found to occur in every component of immune response during anaesthesia and surgery. These alterations represent the body's general physiological responses and are mainly dependent on the extent of surgery, as well as other factors such as the patient's age and health status, medication and blood transfusion. Anaesthetic and operative complications have profound effects on these responses. Basically, the immune response to anaesthesia and surgery is a beneficial reaction, needed in local host defences and wound healing and in preventing the body from making autoantibodies against its own tissues. The responses may, however, contribute to the development of postoperative infections and spread of malignant disease. During uncomplicated conventional surgery, the immune response usually passes clinically unnoticed without any harmful effects. Absent responses and excessively high responses, on the other hand, harm the patient. Our understanding of immunological phenomena and our possibilities of controlling mediator activation are now lagging behind the technical advances made in operative treatment. If we want to decrease operative morbidity and mortality to below their present levels, more attention should be directed to immune responses to major surgery, injuries and operative complications with massive mediator release which place the surgical patient at risk. Experimental evidence suggests that results of treatment in injured and operated patients can in the future be improved by controlling immune responses and their mediator systems. Our current level of knowledge of immune responses is already helping us to avoid many immune-mediated complications. However, routine interference with these responses is not indicated.

AIDS-like disproportion of minor T-cell subsets in Japanese patients with Wegener's granulomatosis

Fifteen Japanese patients with Wegener's granulomatosis (WG) were evaluated according to their lymphocyte subset abnormalities. Two colour immunofluorescent flow cytometry was used to distinguish the lymphocyte subset alterations. WG group showed a decrease in the percentage of CD4+ cells and the increase of CD8+ cells. Within the NK cell family, the functionally unidentified CD8+57+ cells were markedly elevated. The disproportion of the lymphocyte subsets (CD4+ decreases CD8+57+ increases) were similar to those of Acquired Immunodeficiency Syndrome (AIDS) and AIDS relating complexes (ARC). To assess silent infection of Human immunodeficiency virus (HIV), the polymerase chain reaction (PCR) was done for all patients to selectively amplify specific HIV proviral DNA sequences in peripheral blood mononuclear cells, HIV-1 proviral DNA was not found in any patients but these changes of WG might suggest a possible adaptive response to unknown viral infection.

Lymphoid organs function as major reservoirs for human immunodeficiency virus

The total number of human immunodeficiency virus type 1 (HIV-1)-infected circulating CD4+ T lymphocytes is considered to be a reflection of the HIV burden at any given time during the course of HIV infection. However, the low frequency of HIV-infected circulating CD4+ T lymphocytes and the low level or absence of plasma viremia in the early stages of infection do not correlate with the progressive immune dysfunction characteristic of HIV infection. In this study, we have determined whether HIV-infected circulating CD4+ T lymphocytes are a correct reflection of the total pool of HIV-infected CD4+ T cells (i.e., HIV burden). To this end, HIV burden has been comparatively analyzed in peripheral blood and lymphoid tissues (lymph nodes, adenoids, and tonsils) from the same patients. The presence of HIV-1 DNA in mononuclear cells isolated simultaneously from peripheral blood and lymphoid tissues of the same patients was determined by polymerase chain reaction amplification. We found that the frequency of HIV-1-infected cells in unfractionated or sorted CD4+ cell populations isolated from lymphoid tissues was significantly higher (0.5-1 log10 unit) than the frequency in peripheral blood. Comparable results were obtained in five HIV seropositive patients in the early stages of disease and in one patient with AIDS. These results demonstrate that a heavy viral load does reside in the lymphoid organs, indicating that they may function as major reservoirs for HIV. In addition, the finding of a heavy viral load in the lymphoid organs of patients in the early stages of disease may explain the progressive depletion of CD4+ T lymphocytes and the immune dysfunction associated with the early stages of HIV infection.

An activated CD8+ lymphocyte appears in lymph nodes of rhesus monkeys early after infection with simian immunodeficiency virus

Although alterations in T lymphocyte subset distribution and function in the peripheral blood of HIV-infected humans are well defined, the extent to which these reflect changes in other lymphoid compartments is unclear. We have characterized the coincident changes in PBL and lymph nodes (LN)1 after simian immunodeficiency virus of macaques (SIVmac) infection of rhesus monkeys. Whereas no consistent change in CD8+ PBL was noted during the first 60 d after infection, CD8+ lymphocytes increased significantly in number in LN. These CD8+ LN lymphocytes exhibited an increased expression of MHC class II and a decreased expression of leukocyte adhesion molecule-1, suggesting that they were activated, but interestingly did not express CD25 (IL-2 receptor). Moreover, there was no evidence that these CD8+ LN cells were proliferating, suggesting that they had migrated to the LN. These changes in the LN CD8+ lymphocyte population preceded any detectable change in the light microscopic appearance of the LN. When SIVmac-specific effector T cell responses were assessed, the magnitude of virus-specific effector activity was nearly identical in the PBL and LN of each monkey studied. However, the presence of SIVmac-specific effector cells in the LN did not correlate with the presence of CD8+, MHC class II+ cells. These findings suggest that this numerically important CD8+ lymphocyte subpopulation may serve a regulatory function.

Immunosuppression inhibits switch from naive to memory phenotype in human T lymphocytes

Recently, human T cells have been divided into memory (antigen-primed) and naive (unprimed) subsets, which vary in phenotype and function. Immunosuppressive drugs and heparin have been found to inhibit PHA-induced in vitro switching from naive to memory cell phenotype in a process that is at least partly independent of cell proliferation. Furthermore, T cells isolated from immunosuppressed renal allograft recipients were deficient in their in vitro PHA-induced transition from naive to memory phenotype.

Recognition of self within self: specific lymphocyte positioning and the extracellular matrix

In this article, Maria de Sousa and colleagues address the importance of interactions between lymphocytes and extracellular matrix components to lymphocyte migration and positioning, emphasizing the role of the basement membrane and the complex stromal matrix of the lymphoid organs. They conclude that such interactions are of great importance, both in the physiological functioning of the immune system and in organ transplantation.

Detection of circulating Fc epsilon R2/CD23+ monocytes in patients with rheumatic diseases

Recently, in vitro studies have demonstrated that expression of Fc epsilon R2/CD23 on normal monocytes can be specifically induced by IL-4. In order to investigate the interaction of IL-4 and monocytes in rheumatic diseases, flow cytometry studies were performed. Elevated numbers of circulating Fc epsilon R2/CD23+ monocytes were detected in patients with progressive systemic sclerosis (PSS) as compared with controls. In addition, supernatants derived from phytohaemagglutinin-stimulated peripheral blood mononuclear cells of PSS patients contained high activity to induce Fc epsilon R2/CD23 on CD14+ monocytes. An increased frequency of Fc epsilon R2/CD23+ monocytes was also observed in rheumatoid arthritis, and sequential studies in patients with systemic lupus erythematosus showed a close relationship between Fc epsilon R2/CD23+ monocytes and disease activity. It is suggested that IL-4 has an important role in the pathogenesis of PSS by activating monocytes, and might also contribute to monocyte activation in other rheumatic diseases.

Influence of aging on intracellular free calcium and proliferation of mouse T-cell subsets from various lymphoid organs

The influence of aging on T-cell activation and proliferation was examined in lymphocytes derived from peripheral blood, spleen, and lymph nodes of WBB6F1 C57B1/6J x WB/Re) mice. Following activation with anti-CD3 monoclonal antibodies, the greatest age-related changes were seen in CD4+ cells derived from spleens of 27- to 30-month-old mice. These CD4+ lymphocytes showed reduced [Ca2+]i signaling and decreased proliferation in the presence of exogenous interleukin 2. CD8+ cells from spleens of old animals showed reduced [Ca2+]i but not altered proliferation. Both CD4+ and CD8+ cells derived from peripheral blood of old mice showed decreased peak [Ca2+]i, but no defect in cell proliferation. In contrast, age-related deficits in either [Ca2+]i or proliferation were not observed in CD4+ and CD8+ cells from lymph nodes. Additionally, the percentage of CD4+ cells was decreased in all lymphoid organs from old mice, while the percentage of CD8+ cells was similar in lymphoid organs of old and young mice. Old mice had a significant increase in expression of Pgp-1 in CD4+ cells from spleen and peripheral blood and CD8+ cells derived from lymph node. Our studies indicate that there are differential effects of aging in T lymphocytes derived from different lymphoid organs in mice. Among the cell sources and subsets examined, the age-related changes noted in CD4+ cells from mouse peripheral blood were the most similar to those previously observed in the corresponding peripheral blood lymphocyte subset in humans.

Alterations in serum cortisol, CD4+CD8+ lymphocyte sub-population ration and T cell mediated suppression of immune responses in the malnutrition of anorexia nervosa

Serum cortisol and T lymphocyte sub-populations (CD3+, 4+ and 8+) were studied in 22 consecutively admitted patients with anorexia nervosa (AN) who had a mean weight loss of 30%. In addition Concanavalin A (Con A) mitogen induced T cell suppression of lymphocyte response to PPD (purified protein derivative of tuberculin antigen) was analysed. Increased serum cortisol concentrations were found in the AN-patients compared to the control group, with mean levels 654 and 418 nmol/l respectively. The relative numbers of CD4+ lymphocytes (mean 36.2%) and the CD4+ CD8+ ratio (mean 1.54) were significantly reduced (p < 0.05) in the AN-patients compared to the control group (mean 41.6% and 2.14 respectively). T cell mediated, Con A induced suppression of lymphocyte response to PPD was increased in AN-patients compared to the control group with low (1mug/ml) Con A concentration, but unchanged with high (5 mug/ml) Con A concentration. There was no correlation between serum cortisol concentrations and the numbers of T lymphocyte subpopulations or T cell suppressor activity. In contrast, a highly significant correlation existed between serum cortisol and the duration of AN (p < 0.002), but not with relative weight loss or anthropometric variables: triceps skin-fold (TSF) and arm muscle circumference (AMC). Immunological variables were not correlated with duration of disease. Thus, immunological alterations of the T cell system are detectable in AN, but are subtle and their clinical importance is not well known.

Circulating leucocyte and lymphocyte subpopulations before and after intensive endurance exercise to exhaustion

Seventeen healthy cyclists [age 20.8 (SD 4.8) years; body mass 68.3 (SD 7.7) kg; body fat, 11.4 (SD 2.6) %; height, 179.1 (SD 5.9) cm; VO2max, 60.9 (SD 7.4) ml.kg-1.min-1] conducted intensive endurance exercise to exhaustion (stress test, ST) on a cycle ergometer at 110% of their individual anaerobic threshold [Than,individual; exercise intensity, 3.97 (SD 0.6) W.kg-1; duration, 23.9 (SD 8.3) min; maximal lactate concentration, 7.39 (SD 2.59) mmol.l-1]. The distribution of leucocyte subpopulations was measured flow cytometrically: before, immediately after (0), 5 (+5), 30 (+30) and 60 (+60) min after ST. The lymphocytes (0 min) and granulocytes (+60 min) were mainly responsible for the increase of leucocytes. Lymphocytes were significantly lower at +30 and +60 min than before. CD3-CD16/CD56+ (+480%) and CD8(+)-lymphocytes (+211%) increased at 0 min more than the other lymphocyte subpopulations (CD(3+)-cells, +100%; CD(4+)-cells, +56%; CD(19+)-cells, +64%). CD3-CD16/CD(56+)- and CD(8+)-cells also were mainly responsible for the decreased values of lymphocytes at +30 min and +60 min compared to before. At 0 min naive CD(8+)-cells (CD45RA+, CD45RO-) increased more than memory CD(8+)-cells (CD45RA-, CD45RO+). Changes of naive and memory CD(4+)-cells did not differ. All lymphocyte subpopulations, in particular CD(8+)- and CD3-CD16/CD(56+)-cells, decreased rapidly between 0 min and 5 min. We conclude that an intensive endurance exercise to exhaustion causes a mobilisation of lymphocytes, especially of natural killer cells (CD3-CD16/CD56+) and naive, unprimed CD(8+)-cells (CD45RA+, CD45RO-) which may be transported to injured muscles.(ABSTRACT TRUNCATED AT 250 WORDS)