Mixed rosette assay for the detection of T mu and T gamma lymphocytes

Regulated expression of the inhibitory receptor LAIR-1 on human peripheral T cells during T cell activation and differentiation

The leukocyte-associated Ig-like receptor-1 (LAIR-1) is capable of inhibiting immune cell function through interaction with collagens. LAIR is expressed on the majority of peripheral blood mononuclear cells. The abundant expression of both receptor and ligand calls for regulatory mechanisms to relieve the continuous interaction between collagens and LAIR-1. This regulation may occur at the expression level of the receptor. Here, we report that LAIR-1 is indeed differentially expressed during human T cell differentiation. Naive CD4(+) and CD8(+) T cells as well as CD8(+) T cells of the effector phenotype express higher levels of LAIR-1 compared to memory T cells. In vitro stimulation revealed a decrease in LAIR-1 expression upon activation, and the lower LAIR-1 expression on CD127(-) T cells suggests that activation-induced down-modulation of LAIR-1 may also occur in vivo. Furthermore, crosslinking of LAIR-1 on primary T cells results in an inhibition of T cell function. Our data suggest that regulated expression of LAIR-1 and the subsequent change in the threshold for activation may be a mechanism to modulate inhibition of the immune system.

Membrane plasma exchange in patients with metastatic cancer

Seven patients suffering from metastatic cancer and all showing objectively measurable tumours were treated with eight sessions of membrane plasma exchange. No other oncological treatment was administered during the period of plasma exchange. The procedure itself was well tolerated and subjective improvement was reported by some patients. No objective tumour regression was observed. Immune complex-like material and inflammatory proteins were efficiently removed. In some patients a decrease in the number of T lymphocytes, due to relative depletion of T mu cells, was noted.

Distribution of T-cell subpopulations in the peripheral blood of patients with erythrodermic psoriasis

In the present study the percentages of T cells and T-cell subsets, as defined by Fc receptors and monoclonal antibodies (OKT3, OKT4, OKT8, HLA-DR) were determined in the peripheral blood of 12 patients with psoriasis, including six patients with erythroderma and 6 with active, but limited disease. The patients with erythroderma were studied before treatment and 4-8 weeks following. The mean percentages of E-rosette-forming cells and T-cell subsets reactive with the monoclonal antibodies OKT3, OKT4 and OKT8 were within normal limits, as were the percentages of T mu-cells, irrespective of the extent or activity of the disease. The mean percentage of T gamma-cells was reduced in the patients with untreated erythrodermic psoriasis but not in the patients with limited disease. Comparison of the T gamma values in the erythroderma group before and after therapy showed a slight, but statistically significant increase (P less than 0.03). These results indicate a direct relationship between the T gamma deficit and the extent of skin involvement, and argue against a primary suppressor T-cell defect in psoriasis vulgaris.

Fc receptor--more answers, more questions

Fc receptors, belonging to the most important surface structures of a number of cells participating in the immune processes, have been intensely studied during the past decade. The present review summarizes the contemporary knowledge of the specificity and heterogeneity of Fc receptors and of factors influencing their expression, and includes some views on their function. In addition, it mentions their relationship to other cell surface structures, expression of Fc receptors during ontogeny of the organism and in certain diseases. Finally, data concerning the isolation and biochemical characterization of the Fc receptor molecule are presented.

Lymphocyte subpopulations in rheumatoid arthritis. An immunological, enzyme histochemical and morphological study

Peripheral blood lymphocytes (PBL) and synovial fluid lymphocytes ( SFL ) of patients with rheumatoid arthritis (RA) were examined with monoclonal antibodies, with coated ox red blood cells for the expression of Fc receptors for IgG or IgM (T mu and T gamma cells), and incubated for the demonstration of alpha- naphtyl acetate esterase and acid phosphatase. Equal percentages of OKT4 and OKT8 PBL were found in clinically active and inactive RA patients, and in healthy controls, but decreased percentages of OKT4 and increased percentages of OKT8-positive lymphocytes were found among the SFL . The percentages of T mu and T gamma cells, the presence of HLA-DR membrane antigens on T lymphocytes as well as the staining pattern for the enzymes revealed that SFL of patients with RA were highly activated, compared to PBL of RA patients and healthy controls. It can be concluded from this study that a single determination of OKT4 and OKT8-positive lymphocytes in the peripheral blood of RA patients has no predictive value for disease activity. However, the results of the experiments on T lymphocyte-activation clearly showed preferential activation of SFL compared to PBL, indicating that activation of lymphocytes occurs at the site of inflammation.

Diagnostic criteria in Sézary's syndrome: a multiparameter study of peripheral blood lymphocytes in 32 patients with erythroderma

In order to define additional diagnostic criteria for the early diagnosis of Sézary's syndrome (SS), peripheral blood lymphocytes of 32 patients with erythroderma, including 8 patients with SS, 4 patients with erythrodermic mycosis fungoides, 14 patients with an erythroderma on the basis of atopic or chronic dermatitis, and 6 patients with erythrodermic psoriasis, were investigated by computer-assisted morphometry. The degree of nuclear indentation, expressed as the nuclear contour index (NCI), was measured on electron micrographs. The mean NCI and the percentages of cerebriform mononuclear cells (CMC), defined by a NCI greater than or equal to 6.5, were calculated. In addition, the percentages of lymphocytes, T and B cells, and the distribution of T-cell sub-populations as defined by Fc-receptors (T mu, T gamma) and monoclonal antibodies (OKT3, OKT4, OKT8, HLA-DR) were determined. Statistical analysis showed as most discriminating parameters for the differentiation between SS and benign forms of erythroderma: high percentages of lymphocytes (50% or more), an expanded OKT3+, OKT4+ population with an OKT4/OKT8 ratio greater than 10, a mean NCI value greater than or equal to 5.5, the presence of more than 20% CMC, as well as the presence of cells with a NCI greater than or equal to 11.5. The total leukocyte and lymphocyte counts, as well as the percentages of B, T, T mu, and T gamma cells had limited value for the early diagnosis of SS.

Identification and distribution of immunocompetent cells in inflamed gingiva of human chronic periodontitis

Advanced human periodontitis is considered to be a B-cell lesion, but the cellular infiltrate contains several cell types, the distribution of which has not been determined. This experiment was designed to characterize and identify the immunocompetent cells on histological sections and in eluates from diseased human gingiva. Immunoglobulin-bearing cells were detected on histological sections by direct immunofluorescence with F(ab')2 antisera monospecific for human immunoglobulin G (IgG), IgA, or IgM. Plasma cells predominated in the central portion of the lamina propria, with the proportions positive for IgG, IgA, and IgM accounting for 65.2 +/- 9.5, 11.2 +/- 1.1, and 1.3 +/- 1.1% of the total infiltrating cells, respectively. T lymphocytes, identified by indirect immunofluorescence with monoclonal antibody (Leu-1) against human T cells, accounted for 29.3 +/- 10.0% of the total infiltrated cells. Most of the T cells were located subjacent to the pocket epithelium, but there were a few in the central lamina propria. Similarly, Fc receptor-bearing cells detected by EA rosetting and macrophages and monocytes detected by nonspecific esterase staining with alpha-naphthylbutyrate esterase were also localized to the region immediately subjacent to the pocket epithelium. Infiltrated cells were harvested from minced gingival tissue after digestion with collagenase, hyaluronidase, and DNase. The eluates contained 35.3 +/- 6.0% T lymphocytes, 30.0 +/- 14.9% Fc receptor-bearing cells, and 12.9 +/- 4.4% monocytes and macrophages. Whereas T gamma cells comprised 13.3 +/- 1.4% of peripheral blood T cells, they accounted for only 6.0 +/- 2.0% of the eluate T cells. In contrast, T mu cells accounted for 44.7 +/- 4.9% of the T cells in the eluates and 51.6 +/- 4.4% in the peripheral blood. The decreased proportion of T gamma cells in the gingiva may indicate a form of abnormal immune regulation concerned with T suppression of B-cell proliferation.

Detection of Fc receptors

There are an almost bewildering array of assays one can use to detect Fc-receptors, but we have focused, for the most part, on relatively rapid and convenient methods--those that have become standard, e.g., EA rosetting procedures or uptake of soluble antigen-antibody complexes. For most types of Fc-receptor studies these methods are quite adequate. We have also tried to stress the newer methodology of detecting Fc receptors, i.e., the use of anti Fc-receptor antibodies, including monoclonal antibodies. The advent of monoclonal antibody technology, described in detail by Galfrè and Milstein, is changing the approach of many immunological procedures, and detection of Fc receptors is no exception. There are, it should be noted, many newer Fc-receptor methods, e.g., a solid-phase radioimmunoassay and a quantitative fluorometric assay, and methods such as these may be the most appropriate ones to choose in a particular experimental situation. In addition, we have not stressed "functional" Fc-receptor detecting assays, for example, antibody-dependent cell-mediated cytotoxicity (ADCC), which can be used to monitor the activity of Fc receptors in a whole cell population, rather than in single cells.