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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In an attempt to better understand the role of endothelial cells during HIV-1 infection, we report a virological and ultrastructural study on isolated endothelial cells from human adipose tissue, infected by HIV-1 in vitro. Supernatants from cultures showed the presence of p24 antigen and reverse transcriptase activity starting two days after HIV inoculation. A significant decrease of viral rescue was observed in cycloheximide treated cells confirming a de novo synthesis of viral products. SEM analysis individualized several surface slender projections and interdispersed virus-like particles in the infected cells. Furthermore, transmission electron microscopy (TEM) results showed cellular aspects of HIV phagocytosis and virus budding, suggesting that endothelial cells may represent a CD4 negative cell target of HIV-1 infection.
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PMID:Human immunodeficiency virus type-1 (HIV-1) infection of endothelial cells in vitro: a virological, ultrastructural and immuno-cytochemical approach. 137 12

We have studied by flow cytometric analysis the antigen specific activation of CD4+ (helper/inducer) T lymphocytes by purified human thyroid peroxidase (TPO). Peripheral blood mononuclear cells were obtained from 26 patients with Graves' disease (GD), 16 with Hashimoto's thyroiditis (HT), 7 with nontoxic nodular goiter (NG), and 14 normal subjects (N). Cells were cultured for 7 days in the presence or absence of TPO at final concentrations of 3, 30, and 300 ng/mL. When harvested, cells were reacted with an FITC-conjugated anti-CD4 and a PE-conjugated anti-HLA-DR murine monoclonal antibodies. The percentage of HLA-DR+ CD4+ cells (activated CD4+ cells) was determined by a flow cytometer. In the absence of TPO, CD4+ cells had been activated without any specific stimulant. This is known as the autologous mixed lymphocyte reaction (AMLR). In the AMLR, CD4+ cells from GD and HT were less activated compared to those from NG and N. Results of TPO-specific activation were expressed as an incremental increase of activated CD4+ cells (II) (percentage of activated CD4+ cells cultured with TPO minus percentage of activated CD4+ cells cultured without TPO). II of N, GD, HT, and NG were 0.37 +/- 0.21, 2.20 +/- 0.45,** 2.0 +/- 0.66,* and 0.35 +/- 0.27 (mean +/- SEM), respectively (**p less than 0.01; *p less than 0.05 vs N). When patients were further subdivided, the highest mean II was found in patients with hyperthyroid GD (p less than 0.01), followed by euthyroid HT (p less than 0.05) and euthyroid GD (p less than 0.05), however there was no significant difference between hypothyroid HT and N. In conclusion (1) AMLR reactivity of CD4+ cells from GD and HT was impaired, (2) however, CD4+ cells from both GD and HT were significantly more induced by TPO compared to N, and (3) this induction depends, in part, on the in vivo thyroid status.
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PMID:Studies of CD4+ (helper/inducer) T lymphocytes in autoimmune thyroid disease: demonstration of specific induction in response to thyroid peroxidase (TPO) in vitro and its relationship with thyroid status in vivo. 168

T cell subpopulations were assessed by two colour flow cytometry with phycoerythrin conjugated anti-CD45RA and anti-CD29 and fluorescein conjugated anti-CD4 and anti-CD8 monoclonal antibodies, on peripheral blood lymphocytes from 12 patients with systemic sclerosis and from nine control subjects. The percentage of CD4+CD29+ cells was significantly higher in patients with systemic sclerosis than in controls (mean (SEM) 68.8 (3.1) v 47.9 (4.1) respectively). CD4+CD45RA+ cells were not significantly different in patients and controls. CD8+CD29+ and CD8+CD45RA+ subpopulations were significantly higher in patients with systemic sclerosis than in controls (83.0 (3.2) v 58.7 (6.8) and 80.2 (3.0) v 66.9 (3.2) respectively). The increase in the percentage of CD29+ cells suggests an activation of memory cells in patients with systemic sclerosis, which may play an important part in the pathogenesis of the disease.
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PMID:Abnormalities of T lymphocyte subsets in systemic sclerosis demonstrated with anti-CD45RA and anti-CD29 monoclonal antibodies. 171 33

In this study we have correlated peripheral T cell subset phenotypes with intrathyroidal lymphocyte accumulation in patients with autoimmune thyroid disease (Graves' and Hashimoto's disease). Our study utilized euthyroid family members for one of our control groups (n = 48) thus significantly limiting familial, but not disease-specific, influences on these T cell phenotypes. Our principal new observations were found only in patients with Graves' disease. As previously reported, there was a decrease in CD8+ (suppressor/cytotoxic) T cells in the peripheral blood of patients with untreated hyperthyroid Graves' disease (n = 27) (mean +/- SEM, 19 +/- 1.1% in patients compared with 25 +/- 1.2% in controls, p = 0.03), a finding not observed in treated, euthyroid Graves' disease patients or their relatives. However, the relative number of CD8+ T cells, assessed by CD4:CD8 ratios, was increased in the intrathyroidal T cell populations (n = 10), when compared to normal and patient peripheral blood. There were no consistent changes in total CD4+ (helper) T cells in the peripheral blood of patients with treated and untreated Graves' disease but a reduction in CD4+2H4+ (suppressor-inducer) T cells was seen in patients undergoing surgery for Graves' disease (13 +/- 6.9% compared with 39 +/- 3.4%). Again, however, this T cell subset was increased within the target organ of the same patients (41 +/- 5.9%). These data point to either a selective accumulation, or a specific "homing", of certain T cell subsets within the thyroid gland of patients with Graves' disease where T cell differentiation may be strongly influenced by antithyroid drug treatment and the local immune environment.
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PMID:Intrathyroidal accumulation of T cell phenotypes in autoimmune thyroid disease. 171 76

Occupational asthma induced by toluene diisocyanate (TDI) shares several features with allergic asthma, but the mechanism of action of TDI is poorly understood. Ten sensitised subjects, previously shown to develop a dual or late asthmatic reaction after inhaling TDI were examined. In each subject, forced expiratory volume in one second (FEV1) was measured and venous blood was taken before, and 30 minutes and eight, 24, 48, and 72 hours after exposure to TDI (0.005-0.015 ppm for 10-30 minutes). Filtered air was used as a control. Differential leucocyte counts were determined and phenotypic analysis was performed by immunofluorescence on mononuclear cells using monoclonal antibodies (anti-CD3, anti-CD4, anti-CD8, and anti-HLA-DR). Five subjects developed a dual asthmatic reaction and five had a late reaction. Percentage of CD8 positive lymphocytes increased significantly eight hours after exposure to TDI (from 27 +/- 3 (SEM) % to 42.1 +/- 5%) in the subjects with an isolated late reaction. A delayed significant further increase in suppressor/cytotoxic T lymphocytes was seen in seven of the 10 subjects 48 hours after active exposure (from 27 +/- 2% to 42 +/- 4.8%), irrespective of the type of asthmatic reaction developed after exposure to TDI. Eosinophil percentage increased from 2.5% +/- 1.0 to 6.4% +/- 1.2 24 hours after exposure to TDI and the increase was sustained for up to 48 hours (4.7 +/- 1.1%). No significant variations of FEV1 or cell percentages were seen in the controls. In conclusion, the events triggered by exposure to TDI in sensitised subjects included changes in lung function and systemic effects which lasted longer than bonchoconstriction and concerned suppressor/cytotoxic lymphocytes and eosinophils. These results suggest that TDI induced late asthmatic reactions may be associated with an immunological response to TDI or to its products.
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PMID:Increase in numbers of CD8 positive lymphocytes and eosinophils in peripheral blood of subjects with late asthmatic reactions induced by toluene diisocyanate. 184 21

We performed a nationwide epidemiologic study of hypersensitivity pneumonitis (HP) in Japan by questionnaire and found that 835 cases of HP were recognized during the 1980s; 74.4% were summer-type HP, 8.1% farmer's lung, 4.3% ventilation pneumonitis, 4.1% bird fancier's lung, 2.3% other types, such as chemical worker's lung, and 6.8% of unknown causative agent. It was found that the CD4/CD8 ratios of bronchoalveolar lavage (BAL) lymphocytes were significantly different with the type of disease. The ratio was 0.6 +/- 0.1 (mean +/- SEM) in summer-type HP (N = 271), 4.4 +/- 0.7 in farmer's lung (N = 22), 1.6 +/- 0.3 in ventilation pneumonitis (N = 19), and 2.0 +/- 0.5 in bird fancier's lung (N = 19). In farmer's lung, the CD4/CD8 ratio in smokers was 6.2 +/- 1.9 (N = 6) in contrast with 3.4 +/- 0.7 for nonsmokers (N = 16) (p less than 0.05). It has been generally considered that the phenotypes of BAL lymphocytes in patients with HP are predominately CD8 cells. Our present results, however, indicate that the phenotypes of BAL lymphocytes vary with the type of HP, probably depending on factors such as causative agent, smoking, or staging of the disease.
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PMID:Difference in the phenotypes of bronchoalveolar lavage lymphocytes in patients with summer-type hypersensitivity pneumonitis, farmer's lung, ventilation pneumonitis, and bird fancier's lung: report of a nationwide epidemiologic study in Japan. 190 51

Since 1984, the Multicenter AIDS Cohort Study (MACS) has utilized four flow cytometry laboratories to measure T-lymphocyte subset levels semiannually in a large cohort of homosexual men. This report summarizes the steps taken in the MACS laboratories to attain comparability of lymphocyte subset determinations across the centers and over time. Identical flow cytometers, monoclonal antibodies, and analytic procedures have been used, and over a period of time, the procedure for sample preparation was also standardized. Interlaboratory proficiency testing utilizing identical specimens analyzed in the four laboratories was performed to evaluate the comparability of the data among the laboratories. Our results verify that such testing can identify technical bias in flow cytometric evaluations performed at different laboratories. Temporal laboratory consistency in flow cytometric measurements was evaluated using data from each site's HIV-seronegative homosexual reference group. Both sequential 95% confidence intervals (mean +/- 2 x SEM) and the within-person standard deviations of the immune measurements were considered. Significant variation in CD3, CD4, and CD8 lymphocyte subset percentages over time in the seronegative reference population was observed. Our observations indicate that the lymphocyte subset values of this seronegative group should be used to adjust those obtained on the seropositive study participants during a particular time period, thereby allowing improved discrimination of the effects of HIV on T cells in infected individuals. The data presented are of use for designing epidemiologic and intervention studies in HIV-1-infected individuals, especially for calculating sample sizes. The methods we have used to assess the quality of data in the MACS have general application to quality control programs in flow cytometry laboratories. In particular, comparison of sequential confidence intervals and within-person standard deviations for lymphocyte subset determinations on control populations are essential to a comprehensive proficiency testing program because they permit assessment of consistency within a laboratory over time.
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PMID:Quality control in the flow cytometric measurement of T-lymphocyte subsets: the multicenter AIDS cohort study experience. The Multicenter AIDS Cohort Study Group. 196 82

During the inflammatory response, granulocytes and other leukocytes adhere to and emigrate from small venules. Before firm attachment, leukocytes are observed rolling slowly along the endothelium in venules of most tissues accessible to intravital microscopy. The molecular mechanism underlying this early type of leukocyte-endothelial interaction is unknown. Leukocyte rolling was investigated in venules (diameter, 40 microns) of the exposed rat mesentery. Micro-infusion of a recombinant soluble chimera (LEC-IgG) of the murine homing receptor lectin-like cell adhesion molecule 1 (LEC-CAM 1; gp90MEL) into individual venules reduced the number of rolling leukocytes by 89% +/- 2% (mean +/- SEM, n = 20 venules), while a similar CD4 chimera (CD4-IgG) had no effect (inhibition 14% +/- 7%, n = 25). Rolling was also greatly reduced by a polyclonal serum against LEC-CAM 1 (inhibition 84% +/- 3%, n = 35); preimmune serum was ineffective (11% +/- 13% inhibition, n = 28). These findings indicate that LEC-CAM 1 mediates the adhesive interaction underlying leukocyte rolling and thus may play an important role in inflammation and in pathologic conditions involving leukocytes.
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PMID:Lectin-like cell adhesion molecule 1 mediates leukocyte rolling in mesenteric venules in vivo. 204 60

We determined immune function parameters in 41 newly diagnosed patients with chronic lymphocytic leukaemia (CLL) and correlated these findings with the clinical data and the subsequent course of the disease. The ratio of helper to suppressor T cells (CD4/CD8), the proportion of circulating natural killer (NK) cells and the NK activity were significantly low in clinical stage B and C patients. Among patients presenting with advanced disease, those who subsequently had a more severe course, characterised mainly by frequent respiratory infections, were found to have at presentation a significantly lower CD4/CD8 ratio (x +/- SEM = 0.95 +/- 0.09, vs 1.28 +/- 0.14), a very low proportion of NK cells (4.78 +/- 0.85, vs 11.75 +/- 2.1%) and decreased amount of gamma-globulins (0.66 +/- 0.08, vs 0.97 +/- 0.09 g/dl), in comparison with patients with a much milder later course. These simple parameters of immune function seem to have prognostic value for patients with CLL.
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PMID:Prognostic significance of immune function parameters in patients with chronic lymphocytic leukaemia. 213 86

The increased binding in vitro of CD3 CD4 T-lymphocytes from type 1 (insulin-dependent) diabetic patients to beta-cell membrane antigens compared to lymphocytes from control subjects was previously shown to be a marker of cell-mediated immunity, called diabetic rosettes. In the present study diabetic rosettes were detected in some subjects at risk for type 1 diabetes (first degree relatives of type 1 diabetic patients or nondiabetic subjects with previous transient hyperglycaemia). The mean number of lymphocytes adherent to beta-cells (beta-CL) was significantly higher in subjects at risk for type 1 diabetes than in age- and sex-matched control blood bank donors (P less than 10(-6]. This number of beta-CL was higher in type 1 diabetic patients than in subjects at risk (P less than 10(-6], and one-way analysis of variance by rank (Kruskal-Wallis) revealed that the three populations (controls, diabetics, and risk subjects) were different in terms of beta-CL values (P less than 0.001). The percentage of subjects at risk that had a positive test (arbitrarily defined as a beta-CL value higher than the 95th percentile of 228 controls) was 20%. No difference was observed between the two subgroups of subjects at risk in terms of either mean +/- SEM of beta-CL or percentages of individuals with a positive test. These diabetic rosettes were slightly associated with acute insulin response to iv glucose lower than the 5th percentile of controls (immunoreactive insulin at 1 +/- 3 min, 250 pmol/L; by chi 2, P = 0.04) and with HLA DR 3/4 heterozygosity (by chi 2, P = 0.04). They were not associated with islet cell antibodies (regardless of the threshold for positivity, expressed in Juvenile Diabetes Foundation units), insulin autoantibodies, activated (HLA DR+) T-lymphocytes, or sex. A statistical association was detected between HLA DR 3/4 heterozygosity and a low acute insulin response to iv glucose (by chi 2, P less than 0.003). The preliminary (2-yr) longitudinal follow-up revealed that out of five islet cell antibody-positive subjects who progressed to type 1 diabetes, three displayed beta-CL values higher than the 90th percentile of controls. Diabetic rosettes could, thus, be detected in some individuals at risk for type 1 diabetes as a marker of cell-mediated immunity.
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PMID:Beta-cell cytoadherent lymphocytes in some subjects at risk for type 1 (insulin-dependent) diabetes: progression to diabetes within 2 years. 214 83


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