Biomedical subjects

A Condez

Publications and source records attributed to A Condez.

8 recordsLinked to original sources

PubMed1993

Mucosal macrophage subsets of the gut in HIV: decrease in antigen-presenting cell phenotype.

The effect of HIV infection on intestinal lamina propria macrophage subsets was investigated in 41 patients at various stages of HIV infection (asymptomatic HIV infection, n = 17; AIDS, n = 24). Duodenal biopsies taken from HIV patients at endoscopy were snap frozen and cryostat sections cut for immunohistochemical staining. MoAbs CD68 (EBM11, pan-macrophage marker), RFD1 (antigen-presenting cells) and RFD7 (mature phagocytic macrophages) were used to identify cell subsets using indirect immunoperoxidase or alkaline phosphatase. Double immunofluorescence using MoAbs to HIV proteins (p24, p17 and gp120) and RFD1 were used to identify HIV-infected antigen-presenting cells. Double immunofluorescence was also used to identify macrophages that expressed both RFD1 and RFD7 ('suppressor' macrophages). Intensity of HLA-DR expression in lamina propria cells was investigated using a MoAb to HLA-DR directly conjugated to glucose oxidase. The results show that there was no difference in overall density of macrophages, but there was a significant decrease in dendritic cells (RFD1+) in all clinical stages of HIV. There was no difference in the density of RFD7+ macrophages, nor was there a difference intensity of HLA-DR expression in lamina propria cells. Only four HIV-infected cells were positively identified in the 41 patients. This result suggests that the antigen-presenting arm of mucosal immune defences may be seriously compromised in HIV infection, and represents a further insult to mucosal immunity already impaired as a result of loss of CD4+ T lymphocytes. This may contribute to development of opportunist infection in the gut.

Acquired Immunodeficiency Syndrome↗

PubMed1993

Loss of mucosal CD4 lymphocytes is an early feature of HIV infection.

T cell subsets in the gut mucosa are distinct populations and their imbalance in HIV has specific implications in infection. Alterations in T cell subsets in duodenal biopsies were investigated in 17 asymptomatic HIV patients, 24 AIDS patients and 10 controls with non-ulcer dyspepsia. Immunohistochemistry and immunofluorescence using MoAbs to CD3, CD4, CD8, CD68, CD45RA, CD45RO and gp120 were performed on frozen sections. In the lamina propria, there was a significant depletion of CD4+ cells at all stages of HIV, but the density of CD8 lamina propria cells was increased. Intraepithelial lymphocytes were decreased in AIDS patients. There was a significant correlation between cellular density and mucosal CD3+ lymphocytes, and between mucosal CD3+ and CD8+ lymphocytes. Although mucosal CD4,CD45RO+ 'memory' cells were decreased, CD8,CD45RO+ 'memory' cells were increased. Mucosal CD4+ lymphocyte depletion occurred early in HIV, and thus their role in mucosal protection against opportunistic infection should be revised. Mucosal CD8+ lymphocytes initially increased, but decreased when CD4 blood counts were depleted, perhaps contributing to loss of host protection against infection. Intraepithelial lymphocyte depletion may also contribute to opportunistic infection.

Acquired Immunodeficiency Syndrome↗

PubMed1992

T-cell dominated inflammatory reactions in the bronchi of asthmatics are not reflected in matched bronchoalveolar lavage specimens.

Samples of bronchoalveolar lavage (BAL) and endobronchial biopsies were obtained from five patients with clinically diagnosed asthma (ATS criteria). A comparison was made of the presence and distribution of immunocompetent lymphocytes and macrophages within each sample. Significantly raised numbers of T lymphocytes, CD45RO+ lymphocytes, RFD1+ macrophage-like cells and RFD7+ macrophages were seen in the bronchial biopsies. In contrast four out of five of the BAL specimens showed a normal differential cell count, the one exception being a patient exhibiting a degree of lymphocytosis. Further, immunocytological investigation demonstrated a normal distribution of T-cell subsets and macrophage subsets in asthmatic BAL with the exception that in four out of five of these patients a raised number of macrophage-like cells exhibiting phenotypic markers of monocytes was observed. Correlation between BAL and biopsy data was seen in the number of CD45RO+ T-cells present. No other parameters exhibited a significant correlation. Raised expression of HLA-DR was recorded in all asthmatic biopsies, yet lavage cells from the same patients failed to exhibit any increase of HLA-DR density over normal. It is concluded that the immune-associated inflammation present in endobronchial biopsies of clinically stable asthmatics is not reflected in bronchoalveolar lavage samples taken from the same patients.

Acute-Phase Reaction↗

PubMed1992

Lung function and immunopathological changes after inhaled corticosteroid therapy in asthma.

Six patients with asthma (American Thoracic Society (ATS) criteria), maintained on inhaled beta 2-agonists alone, were treated with inhaled corticosteroid (budesonide 400 micrograms b.d.) for a period of three months. Prior to steroid therapy, baseline spirometry, bronchodilator response and bronchial hyperresponsiveness were documented and endobronchial biopsies were obtained for immunopathological analysis. Frozen sections of the biopsies were investigated using immunoperoxidase methods, with a panel of monoclonal antibodies selected to reveal the presence and distribution of lymphocyte and macrophage subsets and HLA-DR expression. After three months the studies were repeated. Studies before steroid therapy revealed a T-cell-dominated inflammation in the bronchial wall of all subjects. Baseline airway obstruction, median (range) forced expiratory volume in one second (FEV1) 78.5 (61-109)% of predicted, with a significant bronchodilator response 20.8 (14-33)% and bronchial hyperresponsiveness to histamine geometric mean (SD) PC20FEV1 0.69 (2.5) mg was documented. Steroid therapy caused a significant reduction in bronchial hyperresponsiveness to histamine, with an increase in geometric mean PC20FEV1 to 2.22 (3.2) mg post steroid (p less than 0.03). Concurrent with a reduction in bronchodilator response and an increase in spirometric variables (improved forced midexpiratory flow (FEF25-75) p less than 0.03), there were marked reductions observed in the overall numbers of T-lymphocytes (CD 2, 5, 8), the numbers of CD45RO+ T-cells, and the numbers of macrophages (RFD1+) with the phenotype of antigen presenting cells. In all six subjects, reductions in the quantitative expression of HLA-DR molecules were also seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

PubMed1991

T cell dominated inflammatory reactions in the bronchioles of asymptomatic asthmatics are also present in the nasal mucosa.

Endobronchial and nasal mucosa biopsies were obtained from 5 patients with clinically-stable, diagnosed asthma (ATS criteria). A comparison was made of the presence and distribution of immunocompetent lymphocytes and macrophages within each sample. The distribution of immunocompetent cells within the nasal biopsies of the asthmatic patients reflected a very similar inflammatory infiltrate to that seen in the bronchial biopsies. Significantly raised numbers of T lymphocytes, CD45RO + lymphocytes, RFD1 + macrophage-like cells and RFD7 + macrophages were seen in both the nasal mucosa and the bronchial biopsies. Increases in HLA-DR expression were also seen in the nasal mucosa biopsies from asthmatics although the increases over normal did not reach statistical significance. It is concluded that inflammation present in the nasal mucosa of asymptomatic asthmatics exhibits cellular characteristics also seen in endobronchial biopsies. This observation offers the possibility that mucosal biopsy may be an alternative and less invasive approach for studying the cells involved in the bronchial inflammatory reaction that possibly predisposes asthmatics to bronchial hyper-responsiveness.

Adolescent↗

PubMed1989

Cell-mediated immunity in pigeon breeders' lung: the effect of removal from antigen exposure.

Eighteen precipitin-positive pigeon breeders, thirteen symptomatic (SPB), with extrinsic allergic alveolitis (EAA), and five asymptomatic (APB), without lung disease, underwent bronchoalveolar lavage (BAL). Cytospins were prepared on which differential cell counts were performed. Immunocytological methods, using monoclonal antibodies, were performed to identify lymphocyte and macrophage subsets. Marked abnormalities in cell populations were observed in both groups but with no suggestion of differences between the groups. All subjects had a lymphocytosis in BAL (SPB 45%; APB 29%). These lymphocytes were almost exclusively T-cells. The cluster designation CD4/CD8 ratio was decreased (SPB 0.86; APB 1.13) and a significantly higher proportion of these cells than normal expressed UCHL1 (an antigen associated with the common leucocyte antigen complex) indicating immune commitment. In the macrophage population increased proportions of cells expressing antigens associated with interdigitating cells (RFD1+) and mature macrophages (RFD7+) were also abnormal. When six SPB patients were relavaged after isolation from pigeons for three weeks, there was a significant reduction in the lymphocytosis and in the proportion of UCHL1+ lymphocytes. This was accompanied by reductions in the percentage of macrophages expressing RFD1 and UCHL1. We suggest that EAA in pigeon breeders is associated with a cell-mediated immune response which is down-regulated by isolating patients from exposure to pigeon derived antigens.

Adult↗

PubMed1988

The effect of intracellular parasitism on cell phenotype.

Human peritoneal macrophages were harvested from 'long dwell' peritoneal dialysis bags. Adherent cells were harvested after 2 h culture on plastic and these were then exposed to M. lepraemurium (MLM) or latex beads (LB) for further culture periods of 2 and 24 h. Immunophenotyping of the macrophages was performed before and after culture both with and without the addition of MLM or LB. Monoclonal antibodies RFD1, RFD7 and RFD9 were used, which in control tissues recognize dendritic cells, mature macrophages and epithelioid cells respectively. MoAb RFDR1 (HLA-DR) was also used. Results revealed that the addition of MLM or LD for 2 h did not significantly alter the original proportions of RFD1+ and RFD7+ cells. A proportion of both RFD1+ and RFD7+ cells were found to phagocytose both MLM and LB, although RFD7+ cells seemed slightly more efficient. After 24 h culture with MLM reduced numbers of cells expressed the RFD1+ marker while increased numbers of cells expressing RFD7+ antigen were present. A concurrent small rise in the proportion of RFD7+ cells parasitized implied that this increase was due to RFD1+ cells becoming RFD7+ cells. Culture for 24 h with MLM significantly reduced the percentage of total cells expressing HLA-DR. Conversely, 24 h culture with MLM was shown to increase the proportion of cells expressing the epithelioid cell marker RFD9. These results suggest that intracellular parasitism may affect the expression of surface antigens on cells and by implication thus affect cell function.

Antibodies, Monoclonal↗

PubMed1987

Influence of 1,25-(OH)2 vitamin D3 and gamma interferon on the phenotype of human peripheral blood monocyte-derived macrophages.

The effects of 1,25-dihydroxy vitamin D3 and gamma interferon on the phenotypic changes associated with monocyte maturation in vitro were investigated. Human monocytes separated from peripheral blood mononuclear cell populations by adherence to plastic were cultured for 7 days on glass. Immunocytological analysis was performed on monolayers fixed at various times by using monoclonal antibodies specific for mature macrophages (RFD7), interdigitating (dendritic) cells (RFD1), and class II major histocompatibility complex antigen (RFDR1). Without any addition to the culture medium, proportions of these monocytes (normally RFD1 and RFD7 negative) developed either RFD1 positivity (23%) or RFD7 positivity (49%) over 7 days of culturing. The addition of gamma interferon to these cultures markedly reduced the proportion of RFD7-positive cells (less than 10%) but increased the proportion of RFD1-positive cells (40 to 60%). In contrast, 1,25-dihydroxy vitamin D3 reduced the expression of both RFD1 and RFD7. Both of these effects were dose dependent and required at least 3 days of contact with the cells. The possibility that RFD1- and RFD7-positive cells represent functionally distinct subsets makes these effects of significance in our understanding of the role of these mediators in controlling the immunocompetence of nonlymphoid accessory cell populations and in macrophage-associated antimicrobial activity.

Antibodies, Monoclonal↗