Fc epsilon receptors on human cell lines and peripheral blood lymphocytes detected by binding of IgE immune complexes

Predictive Value of Cytokines and Immune Activation Biomarkers in AIDS-Related Non-Hodgkin Lymphoma Treated with Rituximab plus Infusional EPOCH (AMC-034 trial)

PURPOSE

The aims of this study were to determine whether pretreatment plasma levels of cytokines and immune activation-associated molecules changed following treatment for AIDS-NHL with rituximab plus infusional EPOCH, and to determine whether pretreatment levels of these molecules were associated with response to treatment and/or survival.

EXPERIMENTAL DESIGN

We quantified plasma levels of B-cell activation-associated molecules (sCD27, sCD30, and sCD23) and cytokines (IL6, IL10, and CXCL13) before and after the initiation of treatment in persons with AIDS-NHL (n = 69) in the AIDS Malignancies Consortium (AMC) 034 study, which evaluated treatment of AIDS-NHL with EPOCH chemotherapy and rituximab.

RESULTS

Treatment resulted in decreased plasma levels of some of these molecules (CXCL13, sCD27, and sCD30), with decreased levels persisting for one year following the completion of treatment. Lower levels of CXCL13 before treatment were associated with complete responses following lymphoma therapy. Elevated levels of IL6 pretreatment were associated with decreased overall survival, whereas higher IL10 levels were associated with shorter progression-free survival (PFS), in multivariate analyses. Furthermore, patients with CXCL13 or IL6 levels higher than the median levels for the NHL group, as well as those who had detectable IL10, had lower overall survival and PFS, in Kaplan-Meier analyses.

CONCLUSIONS

These results indicate that CXCL13, IL6, and IL10 have significant potential as prognostic biomarkers for AIDS-NHL.

B-cell stimulatory cytokines and markers of immune activation are elevated several years prior to the diagnosis of systemic AIDS-associated non-Hodgkin B-cell lymphoma

BACKGROUND

The risk of developing non-Hodgkin lymphoma (NHL) is greatly increased in HIV infection. The aim of this study was to determine whether elevated serum levels of molecules associated with B-cell activation precede the diagnosis of AIDS-associated NHL (AIDS-NHL).

METHODS

Serum levels of B-cell activation-associated molecules, interleukin (IL)6, IL10, soluble CD23 (sCD23), sCD27, sCD30, C-reactive protein (CRP), and immunoglobulin E were determined in 179 NHL cases and HIV+ controls in the Multicenter AIDS Cohort Study, collected at up to 3 time points per subject, 0 to 5 years prior to AIDS-NHL diagnosis.

RESULTS

Serum IL6, IL10, CRP, sCD23, sCD27, and sCD30 levels were all significantly elevated in the AIDS-NHL group, when compared with HIV+ controls or with AIDS controls, after adjusting for CD4 T-cell number. Elevated serum levels of B-cell activation-associated molecules were seen to be associated with the development of systemic [non-CNS (central nervous system)] NHL, but not with the development of primary CNS lymphoma.

CONCLUSIONS

Levels of certain B-cell stimulatory cytokines and molecules associated with immune activation are elevated for several years preceding the diagnosis of systemic AIDS-NHL. This observation is consistent with the hypothesis that chronic B-cell activation contributes to the development of these hematologic malignancies.

IMPACT

Marked differences in serum levels of several molecules are seen for several years prediagnosis in those who eventually develop AIDS-NHL. Some of these molecules may serve as candidate biomarkers and provide valuable information to better define the etiology of NHL.

Association of life style with high risk of hyperimmunity and of immunosuppression mediated by IgE

To test the hypothesis that the increase in allergic prevalence is related not only to environmental allergens, but also to comprehensive life style, we administered to 733 workers at a hard metal plant a questionnaire that included 17 physical and mental health practices. We have shown that eight practices are associated with increases or decreases of total and specific IgE levels, serving to keep them within the normal range (5-400 IU/ml), after controlling for age, sex, and environmental factors. Further confirmation of the definite effect of life style on allergic reactions comes from higher heritability among younger pairs of identical twins of total IgE levels and allergic disorders than among older pairs of identical twins. A marked synergism was found among Undesirable life-style factors as bipolar high-risk factors for the development of allergic diseases or immunosuppression characterized by low natural killer (NK) cell activity through which soluble low-affinity IgE receptor is kept low. An effort to practice Desirable life styles, therefore, may be of benefit in reducing the risk of immunoallergic disorders.

Expression of Fc epsilon receptors and surface and cytoplasmic IgE on human fetal and adult lymphopoietic tissue

The appearance during ontogeny of IgE-positive and Fc epsilon receptor (FcER)-bearing cells was studied. Monoclonal antibody to the constant region (Fc) of IgE (CIA-E-7.12) was used to detect cytoplasmic and surface IgE. A monoclonal antibody to the low-affinity Fc epsilon receptor (FcER-II = CD23) and immune complexes composed of human IgE and mouse monoclonal anti-human IgE Fc were used to detect FcER. Cryostat sections of human fetal tissues (liver, lung, spleen, and thymus) from 11 to 22 weeks gestation as well as adult tonsil tissues were examined for IgE, FcER, and other lymphoid markers by immunoperoxidase staining. Although both IgE- and FcER-positive cells were present in adult tissues, we found that, in contrast to an earlier report, such cells were not present in the fetal tissues examined. The in situ location of FcER on cells in human lymphoid tissues revealed that the FcER-bearing cells were localized predominantly in the germinal centers (mature B cell and macrophage areas) of the tonsil follicles with some staining in the mantle (resting and less mature B cell areas).

Subset of natural killer cells is induced by immune complexes to display Fc receptors for IgE and IgA and demonstrates isotype regulatory function

Expression of Fc receptors for IgE (FcER) or IgA (FcAR) on purified natural killer (NK) cells was investigated. No FcER+ and a few FcAR+ NK cells were detectable on freshly separated NK (NKH-1+) cells from normal donors. Incubation of NK cells with IgE-anti-IgE immune complexes or IgA-anti-IgA immune complexes induced up to 10 and 20% FcER+ or FcAR+ cells, respectively. These FcR were induced on CD3- but not on CD3+ NKH-1+ cells. In contrast, NK cells from patients with various dysgammaglobulinemias could not be induced to express FcER or FcAR corresponding to their abnormal circulating IgE and/or IgA levels. Enriched FcER+ or FcAR+ induced NK cell supernatants from normals enhanced IgE or IgA synthesis from Ig secreting B cell lines in an isotype-specific fashion without increasing proliferation. Thus NK cells, after interaction with specific Ig isotypes in complexes, express FcR and produce differentiation factors for that isotype.

Constitutive production of B cell differentiation factor-like activity by human T and B cell lines

A lymphokine demonstrating human B cell differentiation factor (BCDF)-like activity was isolated from immature (MOLT-4f, CCRF-CEM and CCRF-HSDB-2) and mature (HUT-78) malignant human T lymphoid cell lines and from human B lymphoblastoid cell lines (BJAB and ALL-7031-B). All the cell lines were grown long term in serum-free medium. This BCDF-like activity has a molecular mass in the range of 40-60 kDa and stimulates immunoglobulin synthesis of cell lines capable of producing IgA (GM-1056), IgG (GM-1500 and CESS) and IgM (CBL#3). It was not produced by a myeloid cell line. We were only able to identify the differentiation activity produced by the T and B cell lines by using appropriate molecular mass fractions from the serum-free medium as controls. This BCDF-like activity is different from that of the human BCDF so far described as it has a higher molecular mass and is constitutively produced by malignant T lymphoid cell lines which are human T cell leukemia virus-I negative and by B lymphoblastoid cell lines.

A flow cytometric micromethod for the detection of Fc epsilon receptors and IgE binding factors using fluorescent microspheres

Two assays based on the use of fluorescent microspheres have been developed in order to detect Fc epsilon receptors on human cells and human IgE binding factors. A direct assay using microspheres to which IgE was coupled permitted the detection of Fc epsilon receptors on RPMI 8866 cells. However the fluorescence intensity was relatively low and made it difficult to discriminate between positive and negative cells. To increase the sensitivity of the assay, an indirect 3-step test was developed, in which the cells were subsequently incubated with soluble IgE, a polyclonal or monoclonal anti-IgE antibody and fluorescent microspheres to which anti-mouse or anti-rabbit immunoglobulin was coupled. This indirect assay resulted in an increased fluorescence intensity. Optimal discrimination between positive and negative cells was obtained. This assay permitted the detection of human IgE binding factors produced by RPMI 8866 cells. The binding of IgE was not dependent on the origin of the latter. Among the different cell lines tested, the EBV positive lymphoblastoid cells were found to express Fc epsilon receptors and to release IgE binding factors in their supernatants.