The beneficial effects of treatment with tamoxifen and anti-oestradiol antibody on experimental systemic lupus erythematosus are associated with cytokine modulations

A pregnancy hormone-cell death link promotes enhanced lupus-specific immunological effects

Women of reproductive age demonstrate an increased incidence of systemic lupus erythematosus, and reproductive hormones have been implicated in disease progression. Additionally, pregnancy can be associated with disease "flares", the reasons for which remain obscure. While apoptotic bodies are believed to provide an autoantigenic trigger in lupus, whether autoantigenic constituents vary with varying cellular insults, and whether such variations can be immunologically consequential in the context of pregnancy, remains unknown. As assessed by antigenicity and mass spectrometry, apoptotic bodies elicited by different drugs demonstrated the differential presence of lupus-associated autoantigens, and varied in the ability to elicit lupus-associated cytokines from lupus splenocytes and alter the phenotype of lupus B cells. Immunization of tamoxifen-induced apoptotic bodies in lupus-prone mice generated higher humoral autoreactive responses than did immunization with cisplatin-induced apoptotic bodies, and both apoptotic bodies were poorly immunogenic in healthy mice. Incubation of lupus splenocytes (but not healthy splenocytes) with the pregnancy hormone human chorionic gonadotropin (hCG) along with tamoxifen-induced apoptotic bodies (but not cisplatin-induced apoptotic bodies) induced increases in the secretion of lupus-associated cytokines and in the up-modulation of B cell phenotypic markers. In addition, levels of secreted autoantibodies (including of specificities linked to lupus pathogenesis) were enhanced. These events were associated with the heightened phosphorylation of several signaling intermediates. Observations suggest that hCG is a potential disease-promoting co-stimulant in a lupus-milieu; when combined with specific apoptotic bodies, it enhances the intensity of multiple lupus-associated events. These findings deepen mechanistic insight into the hormone's links with autoreactive responses in lupus-prone mice and humans.

Drug Repurposing for COVID-19 Treatment by Integrating Network Pharmacology and Transcriptomics

Since coronavirus disease 2019 (COVID-19) is a serious new worldwide public health crisis with significant morbidity and mortality, effective therapeutic treatments are urgently needed. Drug repurposing is an efficient and cost-effective strategy with minimum risk for identifying novel potential treatment options by repositioning therapies that were previously approved for other clinical outcomes. Here, we used an integrated network-based pharmacologic and transcriptomic approach to screen drug candidates novel for COVID-19 treatment. Network-based proximity scores were calculated to identify the drug-disease pharmacological effect between drug-target relationship modules and COVID-19 related genes. Gene set enrichment analysis (GSEA) was then performed to determine whether drug candidates influence the expression of COVID-19 related genes and examine the sensitivity of the repurposing drug treatment to peripheral immune cell types. Moreover, we used the complementary exposure model to recommend potential synergistic drug combinations. We identified 18 individual drug candidates including nicardipine, orantinib, tipifarnib and promethazine which have not previously been proposed as possible treatments for COVID-19. Additionally, 30 synergistic drug pairs were ultimately recommended including fostamatinib plus tretinoin and orantinib plus valproic acid. Differential expression genes of most repurposing drugs were enriched significantly in B cells. The findings may potentially accelerate the discovery and establishment of an effective therapeutic treatment plan for COVID-19 patients.

B Cell-Intrinsic mTORC1 Promotes Germinal Center-Defining Transcription Factor Gene Expression, Somatic Hypermutation, and Memory B Cell Generation in Humoral Immunity

B lymphocytes migrate among varied microenvironmental niches during diversification, selection, and conversion to memory or Ab-secreting plasma cells. Aspects of the nutrient milieu differ within these lymphoid microenvironments and can influence signaling molecules such as the mechanistic target of rapamycin (mTOR). However, much remains to be elucidated as to the B cell-intrinsic functions of nutrient-sensing signal transducers that modulate B cell differentiation or Ab affinity. We now show that the amino acid-sensing mTOR complex 1 (mTORC1) is vital for induction of Bcl6-a key transcriptional regulator of the germinal center (GC) fate-in activated B lymphocytes. Accordingly, disruption of mTORC1 after B cell development and activation led to reduced populations of Ag-specific memory B cells as well as plasma cells and GC B cells. In addition, induction of the germ line transcript that guides activation-induced deaminase in selection of the IgG1 H chain region during class switching required mTORC1. Expression of the somatic mutator activation-induced deaminase was reduced by a lack of mTORC1 in B cells, whereas point mutation frequencies in Ag-specific GC-phenotype B cells were only halved. These effects culminated in a B cell-intrinsic defect that impacted an antiviral Ab response and drastically impaired generation of high-affinity IgG1. Collectively, these data establish that mTORC1 governs critical B cell-intrinsic mechanisms essential for establishment of GC differentiation and effective Ab production.

The immunoendocrinology of systemic lupus erythematosus

Immunoendocrinology or the study of the effects of sex steroids and sex chromatin on immune diseases was pioneered by Henry G. Kunkel. In the disease lupus (SLE) the prevalence of female disease is high; the sex ratio is 10 females to every male after puberty. Since Kunkel's death the influences of triggering epitopes like viruses, histocompatibility, the hypothalamic pituitary-adrenocortical axis, nervous system and the effect of sex steroids are all recognized as contributing factors to pathogenesis. It is too simple to say that sex and genetics are the final reason for the female predominance of SLE. Today the likely cause of the disease involves the epigenetics of sex chromatin and the factors detailed above.

Erythema nodosum - review of the literature

Erythema nodosum is the most common form of panniculitis. It may have many aetiological factors. Erythema nodosum occurs three to five times more often in female patients. It appears as erythematous painful rounded nodules, located most often on the anterior surface of the lower extremities, and may be accompanied by systemic symptoms such as fever, malaise and arthralgia. During diagnosis, oncological vigilance should be maintained, because erythema nodosum may be a paraneoplastic symptom. It requires an interdisciplinary approach and exclusion of many underlying causes.

The expression of mouse CLEC-2 on leucocyte subsets varies according to their anatomical location and inflammatory state

Expression of mouse C-type lectin-like receptor 2 (CLEC-2) has been reported on circulating CD11b(high) Gr-1(high) myeloid cells and dendritic cells (DCs) under basal conditions, as well as on a variety of leucocyte subsets following inflammatory stimuli or in vitro cell culture. However, previous studies assessing CLEC-2 expression failed to use CLEC-2-deficient mice as negative controls and instead relied heavily on single antibody clones. Here, we generated CLEC-2-deficient adult mice using two independent approaches and employed two anti-mouse CLEC-2 antibody clones to investigate surface expression on hematopoietic cells from peripheral blood and secondary lymphoid organs. We rule out constitutive CLEC-2 expression on resting DCs and show that CLEC-2 is upregulated in response to LPS-induced systemic inflammation in a small subset of activated DCs isolated from the mesenteric lymph nodes but not the spleen. Moreover, we demonstrate for the first time that peripheral blood B lymphocytes present exogenously derived CLEC-2 and suggest that both circulating B lymphocytes and CD11b(high) Gr-1(high) myeloid cells lose CLEC-2 following entry into secondary lymphoid organs. These results have significant implications for our understanding of CLEC-2 physiological functions.

Effect of raloxifene on disease activity and vascular biomarkers in patients with systemic lupus erythematosus: subgroup analysis of a double-blind randomized controlled trial

OBJECTIVES

The purpose of this study was to identify the effect of raloxifene on disease activity and vascular biomarkers in patients with systemic lupus erythematosus (SLE).

METHODS

Subgroup data were analyzed for postmenopausal female SLE patients who participated in a randomized controlled trial of raloxifene on glucocorticoid-induced osteoporosis. Patients who were receiving a stable daily dose of prednisolone (≤10 mg) for ≥6 months were assigned to receive raloxifene (60 mg/day) or placebo on top of calcium and vitamin D. Disease activity was assessed by the Safety of Estrogens in Lupus Erythematosus National Assessment (SELENA), SLE disease activity index (SLEDAI) and physicians' global assessment (PGA) every three months. Lupus flares were assessed by the SELENA flare instrument. Serial serum levels of homocysteine, high-sensitivity C-reactive protein (hsCRP) and soluble thrombomodulin (sTM) were measured.

RESULTS

A total of 62 patients (30 raloxifene, 32 placebo) were studied (age 52.5 ± 6.7 years; SLE duration 9.3 ± 7.6 years; menopause duration 7.2 ± 6.6 years). The SLEDAI at entry was 1.8 ± 2.3 (SLEDAI ≥ 6 in 8%). After 12 months, a significant gain in bone mineral density (BMD) of the lumbar spine (1.6%, p = 0.02), and reduction in bone resorption and formation markers was observed in the raloxifene but not in the placebo treated patients. The SELENA-SLEDAI and PGA scores area under the curve over 12 months were not significantly different between the two groups. There were three episodes of mild/moderate lupus flares (33% musculoskeletal, 33% dermatological) in the raloxifene group, compared to nine episodes of mild/moderate flares (27% musculoskeletal, 45% dermatological) in the placebo group (p = 0.11). The low density lipoprotein (LDL) cholesterol level increased significantly in the placebo but not raloxifene treated patients. No significant changes in homocysteine, hsCRP and sTM levels were observed in either group of patients.

CONCLUSIONS

Raloxifene significantly improves lumbar spine BMD in SLE patients but does not cause an increase in lupus activity or flares.

Tamoxifen alleviates hepatitis C virus-induced inhibition of both toll-like receptor 7 and JAK-STAT signalling pathways in PBMCs of infected Egyptian females

Summary.  Hepatitis C virus (HCV) is a major health concern in Egypt being highly prevalent among Egyptians. The two genders experience different responses to HCV infection and show variations in response to interferon (IFN)-based therapy that may be attributed to sex hormones. We previously demonstrated the suppressive effect of 17β-estradiol (E2) on the expression of the IFN-stimulated gene MxA in HCV-infected peripheral blood mononuclear cells (PBMCs). The selective oestrogen receptor (ER) modulator Tamoxifen has been shown to have an antiviral effect against HCV, but its effect on the host immune response is unknown. We investigated the effect of Tamoxifen on the IFN signalling pathways in PBMCs of HCV-infected Egyptian females. We pooled PBMCs and treated then with exogenous interferon alpha (IFNα) or the TLR7 ligand, Imiquimod, and quantified the relative expressions of MxA using RTqPCR. Studies were performed with and without Tamoxifen pretreatment. Pretreatment with Tamoxifen reversed the suppressive effect of E2 on the JAK-STAT pathway in IFNα-treated PBMCs as indicated by a significant increase in MxA expression (P = 0.05*). Tamoxifen pretreatment also significantly upregulated MxA expression in Imiquimod-treated PBMCs (P = 0.0011**), an effect not ascribed to ER blocking nor to an upregulation in TLR7 expression because Tamoxifen showed no potentiating effect on the expression of the receptor. In conclusion, our findings reveal that Tamoxifen has immunomodulatory effects whereby it enhances the host IFN signalling pathways during HCV infection.

17β-Estradiol (E-2) administration to male (NZB × SWR)F1 mice results in increased IdLNF1-reactive memory T-lymphocytes and accelerated glomerulonephritis

While it has been shown that estradiol treatment accelerates the onset of lupus nephritis with autoantibody production and kidney damage in both male and female lupus-prone mice, the specific mechanism(s) involved are unknown. Our previous work has shown that alterations in IdLNF1-reactive T cells and IdLNF1+ antibodies correlated closely with the onset of autoimmune nephritis in female F1 progeny of SWR and NZB (SNF1) mice, supporting a critical role for the IdLNF1 idiotype in the development of disease. Since male SNF1 mice normally do not develop nephritis, we tested whether administration of 17β-estradiol (E-2) to male SNF1 mice would increase IdLNF1 IgG levels and autoreactive T cells, and further, induce nephritis. We found that E-2-treated male SNF1 mice developed nephritis with the same time course and mean survival as normal female SNF1 mice. Moreover, it appeared that the mechanism involved increased serum IdLNF1+IgG and its deposition in kidney glomeruli, preceded by astriking twofold increase in T-lymphocytes expressing the memory phenotype (CD44+CD45RBlo) predominantly in the IdLNF1-reactive T-cell population. In addition, we noted that cells with this phenotype were increased in the nephritic kidneys of treated mice, suggesting a direct involvement of those cells in the renal pathology. E-2 treatment also induced increased numbers of pathogenic IdLNF1+ antibody-producing B cells and elevated presentation of pathogenic IdLNF1+ peptide. Taken together, these results suggest a mechanism of E-2-induced acceleration of autoimmune disease in lupus-prone mice may involve expansion of autoreactive idiotypic T and B-cell populations.

Raloxifene modulates estrogen-mediated B cell autoreactivity in NZB/W F1 mice

OBJECTIVE

Estrogen has been found to exacerbate disease activity in murine lupus and to induce a lupus-like syndrome in nonspontaneously autoimmune mice. This has led to the consideration that estrogen may be a risk factor for the development of systemic lupus erythematosus (SLE), and selective estrogen receptor modulators (SERM) may serve to ameliorate lupus activity. We evaluated the effects and mechanism of action of the SERM raloxifene in murine lupus.

METHODS

Effects of raloxifene on the development of lupus in NZB/W F1 mice were evaluated in the presence and absence of estrogen by assessing the serum DNA reactivity, glomerular IgG deposition and kidney damage, B cell maturation and selection, and activation status of marginal zone and follicular B cells.

RESULTS

Compared to estradiol-treated mice, mice treated with estradiol and raloxifene had significantly lower serum anti-DNA antibody levels and less kidney damage. These effects of raloxifene were due, at least in part, to antagonism of the influence of estrogen on DNA-reactive B cells. Raloxifene was found to prevent estrogen-mediated suppression of autoreactive B cell elimination at the T1/T2 selection checkpoint, to reduce estrogen-induced CD40 overexpression on follicular B cells, making them less responsive to T cell costimulation, and to ameliorate estrogen-mediated CD22 downregulation on marginal zone B cells, thereby decreasing their responsiveness to B cell antigen receptor-mediated stimuli.

CONCLUSION

Raloxifene suppressed estrogen-mediated effects on the survival, maturation, and activation of autoreactive B cells in NZB/W F1 mice.

Estrogen receptor signaling and its relationship to cytokines in systemic lupus erythematosus

Dysregulation of cytokines is among the main abnormalities in Systemic Lupus Erythematosus (SLE). However, although, estrogens, which are known to be involved in lupus disease, influence cytokine production, the underlying molecular mechanisms remain poorly defined. Recent evidence demonstrates the presence of estrogen receptor in various cell types of the immune system, while divergent effects of estrogens on the cytokine regulation are thought to be implicated. In this paper, we provide an overview of the current knowledge as to how estrogen-induced modulation of cytokine production in SLE is mediated by the estrogen receptor while simultaneously clarifying various aspects of estrogen receptor signaling in this disease. The estrogen receptor subtypes, their structure, and the mode of action of estrogens by gene activation and via extranuclear effects are briefly presented. Results regarding the possible correlation between estrogen receptor gene polymorphisms and quantitative changes in the receptor protein to SLE pathology and cytokine production are reviewed.

A new model of induced experimental systemic lupus erythematosus (SLE) in pigs and its amelioration by treatment with a tolerogenic peptide

INTRODUCTION

Systemic lupus erythematosus (SLE) is characterized by a variety of autoantibodies and systemic clinical manifestations. A tolerogenic peptide, hCDR1, ameliorated lupus manifestations in mice models. The objectives of this study were to induce experimental SLE in pigs and to determine the ability of hCDR1 to immunomodulate the disease manifestations.

RESULTS AND DISCUSSION

We report here the successful induction, by a monoclonal anti-DNA antibody, of an SLE-like disease in pigs, manifested by autoantibody production and glomerular immune complex deposits. Treatment of pigs with hCDR1 ameliorated the lupus-related manifestations. Furthermore, the treatment downregulated the gene expression of the pathogenic cytokines, interleukin (IL)-1beta, tumor necrosis factor alpha, interferon gamma, and IL-10, and upregulated the expression of the immunosuppressive cytokine transforming growth factor beta, the antiapoptotic molecule Bcl-xL, and the suppressive master gene, Foxp3, hence restoring the expression of the latter to normal levels. Thus, hCDR1 is capable of ameliorating lupus in large animals and is a potential candidate for the treatment of SLE patients.

Soy isoflavones supplementation alleviates disease severity in autoimmune-prone MRL-lpr/lpr mice

Soy isoflavones supplements, which are phyto-oestrogens widely used as alternatives to alleviate menopausal syndromes or prevent chronic diseases, may exert oestrogenic and anti-oestrogenic activities. This study aimed to investigate the effects of soy isoflavones supplement on oestrogen-related autoimmune disease, such as systemic lupus erythematosus, using autoimmune-prone female MRL- lpr/lpr mice. Eighty mice of 8 weeks were divided into five groups: 0 (Control), 2 (Isf 2), 10 (Isf 10) and 20 (Isf 20) mg/kg BW/day Phyto SoyaTM isoflavones or 0.375 mg/kg BW/day tamoxifen (TAM) as the positive control, by tube-feeding. Some mice were killed at age 15 weeks for cellular cytokine secretion. The data suggested that the Isf 20 and TAM groups had higher weight gain and survival compared with the control group. At age 22 weeks, the Isf 20 group still had 75% survival comparable to mice treated with TAM. At age 14 weeks, the TAM group showed significantly lower serum anti-double-stranded (ds) DNA IgG and anti-cardiolipin IgG. The mice in the Isf 10 and Isf 20 groups also had lower anti-dsDNA IgG and anti-cardiolipin IgG. The interferon (IFN)-γ secretion from mitogen-stimulated T cells in the Isf 20 and TAM groups were significantly lower than those of control mice. Furthermore, the oestrogenic activity of the methanol extracts of soy isoflavones for oestrogen receptor (ER)β, but not ERα, significantly increased, suggesting that soy isoflavones have a selective modulation of ER activation. Thus, soy isoflavone supplementation did not aggravate murine lupus, but apparently ameliorated the disease.

Prevalence and associated factors of allergic rhinitis and atopic dermatitis in children

Allergic disorders are the chronic diseases of greatest pediatric morbidity, affecting over 25 % of the pediatric population. Indeed, this situation has been referred to as an "allergic epidemic". In comparison with asthma, atopic dermatitis and allergic rhinitis have been less extensively investigated, although this does not mean that they should be regarded as minor disorders but rather as alterations that affect the quality of life of the patients and their families, which generate considerable direct and indirect costs. Despite an important research effort, the reason for this allergic epidemic is not well known. These are multifactor disorders without a single causal agent, in which the most important component is the genetic predisposition of the patient (atopy), modulated by environmental factors, exposure to allergens, infections and irritants, among others. A confounding element is the fact that the concept of allergic diseases encompasses phenotypes of rhinitis, atopic dermatitis or asthma in which no IgE-mediated atopic mechanism is demonstrated, and which can manifest in a way similar to true allergic phenotypes. Differentiation between the two is difficult to establish on the basis of self-administered questionnaires alone, in the absence of a precise etiological diagnosis. The present article reviews the numerous factors suggested to be responsible for the increase in allergic diseases recorded in the last few decades, and for the differences in prevalence observed among centres. For most of these factors the results published in the literature are contradictory, in some cases due to a lack of control of the associated interacting or confounding factors. Consensus exists for only some of these causal factors, such as the established parallelism between the increase in allergic diseases and the reduction in infectious processes on one hand, and the increase in particles generated by diesel fuel combustion on the other. In addition, the implicated factors could act differently (and in some cases even antagonically) upon atopy and on the different disease phenotypes, thereby complicating the study of these interactions even further.

Understanding sex biases in immunity: effects of estrogen on the differentiation and function of antigen-presenting cells

The initiation and perpetuation of innate and adaptive immunity is dependent on the ability of professional antigen-presenting cells (APCs) to sense inflammatory stimuli; produce cytokines; and internalize, degrade, and present antigens via surface major histocompatibility complex (MHC) molecules. Dendritic cells (DCs), macrophages, and B lymphocytes express estrogen receptors, indicating that the steroid sex hormone estrogen might directly modulate the function of these cells during immune responses. Sex-specific parameters of immune function have been identified during autoimmunity and the pathogenesis of infectious disease, which show sex biases in their incidence and manifestation; female immunity also varies as estrogen levels change. In this article, we summarize studies that demonstrate effects of estrogen on the differentiation or function of APCs in model in vitro systems, or under circumstances of natural or imposed variation in estrogen levels in vivo.

Systemic lupus erythematosus and breast cancer

There is evidence that certain connective tissue diseases such as scleroderma are associated with an increased risk of malignancy. Although it has been claimed that systemic lupus erythematosus (SLE) carries an increased risk of breast cancer, review of the available literature suggests that this is not the case, or, any increase is very small. Women with SLE do not need to be under close surveillance for breast cancer. In patients suffering from both SLE and breast cancer, radiotherapy has been regarded as relatively contraindicated because of fears concerning early and late complications. This view is not supported by the available literature and the majority of such cases can be treated by standard breast-conserving therapy, including breast irradiation.

Common adjuvant breast cancer therapies do not inhibit cancer vaccine induced T cell immunity

Cancer vaccines may have the most potential for clinical impact when used in the adjuvant setting when tumor burden is at its lowest. Application of cancer vaccines in the adjuvant setting, however, requires integration of immunization with more standard cytotoxic or cytostatic therapies. Common adjuvant therapies for breast cancer patients, i.e. trastuzumab, bisphosphonates and hormonal agents are often administered over several years requiring concurrent administration of these drugs with active immunization. We questioned whether these common adjuvant therapies would impact a patient's ability to develop tumor specific immunity with vaccination. Immune parameters from 36 subjects were evaluated. We determined these adjuvant therapies have no impact on the ability to develop an immune response specific for HER-2/neu peptides (P>0.1) nor do they have an impact on the magnitude of T cell immunity developed with concurrent vaccination (P>0.1). This is the first report to show that the use of trastuzumab, bisphosphonates and hormonal therapy concurrent with cancer vaccine administration have no impact on either the generation or the magnitude of vaccine induced immunity.

Estrogen distinctively modulates spleen DC from (NZB x NZW) F1 female mice in various disease development stages

Estrogen is important in the pathogenesis of systemic lupus erythematosus (SLE). The modulation of estrogen on dendritic cells (DCs) may involve in SLE development. Our purpose was to find out whether in vitro the effect of estrogen on DCs is correlated with the disease progression in vivo. We compared the effects of 17beta-estradiol (E2) on spleen DCs from SLE murine model-(NZB x NZW) F1 female mice before and after the disease onset. Results showed that E2 changed the surface molecule CD40, cytokines IL-6, IL-10, IL-12 and TNFalpha and stimulatory ability of spleen DCs from the mice. Selective estrogen receptor modulator-tamoxifen (TAM) could antagonize E2 effects and E2 could influence estrogen receptor (ER alpha) level in DCs. The changes of DCs from various age old mice were different even contrast. So E2 participates in SLE through modulating DCs by binding ER alpha. The effects of E2 on DCs from mice in various disease progression stages were different.

Raloxifene for postmenopausal women with systemic lupus erythematosus: a pilot randomized controlled study

OBJECTIVE

To study the effects of raloxifene on disease activity and bone mineral density (BMD) in postmenopausal women with systemic lupus erythematosus (SLE).

METHODS

Postmenopausal women with osteopenia and inactive SLE were randomly assigned to receive either raloxifene (60 mg/day) plus elemental calcium (1,200 mg/day) or elemental calcium alone (control). Patients with a history of thromboembolism or antiphospholipid antibody positivity were excluded. BMD at various sites was serially measured, and lupus activity was serially assessed using the Safety of Estrogens in Lupus Erythematosus: National Assessment-Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI).

RESULTS

The study group comprised 33 patients (16 assigned to receive raloxifene and 17 controls, mean +/- SD age 53.8 +/- 5.3 years). Age, body mass index, and baseline BMD values did not differ significantly between the 2 groups of patients. All patients were receiving low-dose prednisolone. After 12 months, femoral neck BMD (mean +/- SD -2.6 +/- 1.0%; P = 0.02) and lumbar spine BMD (-3.3 +/- 0.8%; P = 0.001) decreased significantly in the controls but not in the raloxifene group. No patient had a major flare of lupus, but mild/moderate flares occurred in 4 raloxifene-treated and 6 control patients (P = 0.79). The total area under the curve of SELENA-SLEDAI scores was not significantly different between the 2 groups. A significant increase in the high-density lipoprotein cholesterol level and a reduction in the low-density lipoprotein cholesterol level were observed in the raloxifene group but not in controls. One patient in the raloxifene group (6%) withdrew from the study because of hot flushes. No thromboembolic events were reported.

CONCLUSION

Raloxifene was well tolerated in Chinese patients with SLE who had inactive disease and in whom hypercoagulability was not identified. Raloxifene maintained femoral neck and spinal BMD in patients receiving corticosteroids.

The Selective Estrogen Receptor Modulators, Tamoxifen and Raloxifene, Impair Dendritic Cell Differentiation and Activation

Most immune cells, including myeloid progenitors and terminally differentiated dendritic cells (DC), express estrogen receptors (ER) making these cells sensitive to estrogens. Our laboratory recently demonstrated that 17-beta-estradiol (E2) promotes the GM-CSF-mediated development of CD11c+ CD11b(int) DC from murine bone marrow precursors. We tested whether the therapeutic selective estrogen receptor modulators (SERM), raloxifene and tamoxifen, can perturb DC development and activation. SERM, used in treatment of breast cancer and osteoporosis, bind to ER and mediate tissue-specific agonistic or antagonistic effects. Raloxifene and tamoxifen inhibited the differentiation of estrogen-dependent DC from bone marrow precursors ex vivo in competition experiments with physiological levels of E2. DC differentiated in the presence of SERM were assessed for their capacity to internalize fluoresceinated Ags as well as respond to inflammatory stimuli by increasing surface expression of molecules important for APC function. Although SERM-exposed DC exhibited increased ability to internalize Ags, they were hyporesponsive to bacterial LPS: relative to control DC, they less efficiently up-regulated the expression of MHC class II, CD86, and to a lesser extent, CD80 and CD40. This phenotype indicates that these SERM act to maintain DC in an immature state by inhibiting DC responsiveness to inflammatory stimuli. Thus, raloxifene and tamoxifen impair E2-promoted DC differentiation and reduce the immunostimulatory capacity of DC. These observations suggest that SERM may depress immunity when given to healthy individuals for the prevention of osteoporosis and breast cancer and may interfere with immunotherapeutic strategies to improve antitumor immunity in breast cancer patients.

Tamoxifen Blocks Estrogen-Induced B Cell Maturation but Not Survival

Estrogen treatment has been shown not only to exacerbate disease activity and accelerate death in spontaneous murine models of lupus but also to induce a lupus-like phenotype in non-spontaneously autoimmune mice. In mice transgenic for the H chain of an anti-DNA Ab, estrogen rescues naive autoreactive B cells that normally are deleted and causes them to mature to a marginal zone phenotype. Estrogen further leads to the activation of this population causing an elevation of serum anti-DNA Ab titers and renal disease. This study was designed to evaluate the therapeutic potential of tamoxifen, a selective estrogen receptor modulator, on estrogen-induced lupus. Mice treated with both estradiol and tamoxifen showed no elevation in anti-DNA Ab titers and consequently no glomerular IgG. The DNA-reactive B cell population that is rescued by estrogen was present in an anergic state in mice treated with both estradiol and tamoxifen. Estradiol enhances transitional B cell resistance to apoptosis and expands the population of marginal zone B cells; tamoxifen did not impede the enhanced resistance to apoptosis, but prevented the development of autoreactive cells as marginal zone B cells. Thus, estrogen-induced autoimmunity proceeds through two distinct molecular pathways, one affecting survival and the other maturation. Activation, but not survival, of autoreactive B cells can be abrogated by tamoxifen. Drugs that modulate even some of the effects of estrogen may be beneficial in patients with lupus. Eventually, understanding the pathways involved in survival and activation of autoreactive B cells will permit the development of therapeutics that target all relevant pathways.

Quantitative appraisal of murine filariasis confirms host strain differences but reveals that BALB/c females are more susceptible than males to Litomosoides sigmodontis

Litomosoides sigmodontis, a rodent filarial nematode, can infect inbred laboratory mice, with full development to patency in the BALB/c strain. Strains such as C57BL/6 are considered resistant, because although filarial development can occur, circulating microfilariae are never detected. This model system has, for the first time, allowed the power of murine immunology to be applied to fundamental questions regarding susceptibility to filarial nematode infection. As this is a relatively new model, many aspects of the biology remain to be discovered or more clearly defined. We undertook a major analysis of 85 experiments, to quantitatively assess differences in filarial survival and reproduction in male versus female and BALB/c versus C57BL/6 mice over the full course of infection. This large dataset provided hard statistical support for previous qualitative reviews, including observations that the resistant phenotype of C57BL/6 mice is detectable as early as 10 days postinfection (dpi). An unexpected finding, however, was that filarial survival was reduced in male BALB/c mice compared to their female counterparts. Worm recovery as well as the prevalence and density of microfilariae were higher in female compared with male BALB/c mice. Therefore, L. sigmodontis bucks the filarial trend of increased susceptibility in males. This could be partially explained by the different anatomical locations of adult L. sigmodontis versus lymphatic filariae. Interestingly, the effects of BALB/c sex upon microfilaremia were independent of worm number. In summary, this study has significantly refined our understanding of the host-L. sigmodontis relationship and, critically, has challenged the dogma that males are more susceptible to filarial infection.

Genetic polymorphisms in tumor necrosis factor (TNF)-alpha and TNF-beta in a population-based study of systemic lupus erythematosus: associations and interaction with the interleukin-1alpha-889 C/T polymorphism

Tumor necrosis factor (TNF) is involved in the pathogenesis of systemic lupus erythematosus (SLE), but the role of TNF polymorphisms in SLE susceptibility remains unclear. Previous studies in different populations report an inconsistent association of the TNF-alpha -308A allele with SLE, sometimes depending on the presence of HLA-DR3. We examined the association of polymorphisms in TNF-alpha (-308G/A, -238G/A) and TNFbeta (+252A/G) in a population-based study of SLE in the southeastern United States and considered TNF-SLE associations with respect to HLA-DR3 and DR2 and the interleukin (IL)-1alpha -889C/T polymorphism, previously linked to SLE in this population. Genotypes were analyzed for 230 recently diagnosed SLE patients who met American College of Rheumatology classification criteria and 276 age- and sex-matched controls, randomly selected from driver's license registries. Carriage of the TNF-alpha -308A allele was significantly associated with SLE in Caucasians (OR = 2.3; 95% CI 1.4, 3.9), but not African Americans. Analyses stratified by IL-1alpha -889 genotypes (C/C vs C/T or T/T) revealed independent associations of SLE with TNF-alpha -308A or HLA-DR2 and DR3. This reflected a significant interaction of TNF and IL-1 genotypes in Caucasians, and yielded a strong association (OR = 8.0, p < 0.00001) for the combined "HLA-DR3, TNF-alpha -308A, IL-1alpha -889C/C" genotype. These findings provide evidence of cytokine gene epistasis in SLE susceptibility.

Intraocular injection of tamoxifen-loaded nanoparticles: a new treatment of experimental autoimmune uveoretinitis

In this study, we tested the efficiency of an intravitreal injection of tamoxifen, a non-steroidal estrogen receptor modulator, in retinal soluble antigen (S-Ag)-induced experimental autoimmune uveoretinitis (EAU). To increase the bioavailability of tamoxifen, we incorporated tamoxifen into polyethylene glycol (PEG)-coated nanoparticles (NP-PEG-TAM). The localization of the nanoparticles within the eye was investigated using fluorescent-labeled PEG-coated nanoparticles after injection into the vitreous cavity of rats with EAU. Some nanoparticles were distributed extracellularly throughout the ocular tissues, others were concentrated in resident ocular cells and in infiltrating macrophages. Whereas the injection of free tamoxifen did not alter the course of EAU, injection of NP-PEG-TAM performed 1-2 days before the expected onset of the disease in controls resulted in significant inhibition of EAU. NP-PEG-TAM injection significantly reduced EAU compared to injection of NP-PEG-TAM with 17beta-estradiol (E2), suggesting that tamoxifen is acting as a partial antagonist to E2. Diminished infiltration by MHC class II(+) inflammatory cells and low expression of TNF-alpha, IL-1beta, and RANTES mRNA were noted in eyes of NP-PEG-TAM-treated rats. Intravitreal injection of NP-PEG-TAM decreased S-Ag lymphocyte proliferation, IFN-gamma production by inguinal lymph node cells, and specific delayed-type hypersensitivity indicative of a reduced Th1-type response. It increased the anti-S-Ag IgG1 isotype indicating an antibody class switch to Th2 response. These data suggest that NP-PEG-TAM inhibition of EAU could result from a form of immune deviation. Tamoxifen-loaded nanoparticles may represent a new option for the treatment of experimental uveitis.

Design, synthesis, and evaluation of peptides with estrogen-like activity

Currently used antiestrogenic drugs against hormone-dependent breast cancer, and estrogenic drugs used in treatment of osteoporosis, are associated with risk factors. Therefore, there is a strong need to develop selective estrogen receptor modulators with better tissue selectivity. In a recent study (Peptides, 2002, Vol. 3, 573-580), we used a monoclonal antibody to estradiol (mAb-E2) to screen a phage-display peptide library. We identified a 15-mer peptide (peptide H5) that recognizes mAb-E2 (IC(50) 1 microM) and estrogen receptor (ER)alpha (IC(50) 500 microM) but not ERbeta, and displays estrogen-like activity in vitro and in vivo. In this study, we designed and prepared peptides based on peptide H5, which possess improved estrogenic activity, by evaluating their binding to mAb-E2 and to ERs. Initially, we determined the minimal binding sequence of peptide H5 capable of binding mAb-E2 and ER. Subsequently, systematic single-residue replacements of the minimal sequence, followed by multiple-residue replacements, yielded hexa- and heptapeptides with increased affinities to mAb-E2 and to ER. The most promising peptides, VSWFFE (EMP-1) and VSWFFED (EMP-2) (EMP: estrogen-mimetic peptide), bind mAb-E2 with high affinity (IC(50) of 6 and 30 nM, respectively), recognize ERs with increased affinity (IC(50) of 100 microM for ERalpha, and 100-250 microM for ERbeta), and possess estrogenic activity in vivo. The short peptides described in this study may be used as potential lead compounds for developing new ER ligands.

Possible mechanisms of gender bias in SLE: a new hypothesis involving a comparison of SLE with atopy

The prevalence of systemic lupus erythematosus (SLE) is far higher in females than in males, and numerous investigations of this gender bias have been performed from several perspectives. Sex hormones, particularly estrogens, may be significant in causing the gender discrepancy. This article discusses the possible importance of estrogens in regulating the expression of and responsivity to autoantigens in SLE and in atopic disorders, which are associated with hyperreactivity to exogenous antigens. Estrogens seem to play an important role in the overexpression of endogenous autoantigens, such as human endogenous retroviruses (HERV), and this may be related to the existence of a gender bias in the incidence of SLE but not atopy.

Estrogen disrupts chemokine-mediated chemokine release from mammary cells: implications for the interplay between estrogen and IP-10 in the regulation of mammary tumor formation

Chemokines are pro-inflammatory cytokines that function to attract immune cells to the sites of tissue inflammation, injury or infection. We have formulated the hypothesis that release of one chemokine can serve, in a local paracrine or endocrine fashion, to induce the release of other chemokines from neighboring mammary cells. We set out to investigate whether specific chemokines could promote the release of other chemokine members from mammary cells, and whether estrogen could serve to disrupt the release of these chemokines from mammary cells. We found that treatment with the chemokine IP-10 resulted in significant increases in the amount of MIP-1alpha and MCP-1/JE released from murine mammary cells. Estrogen co-treatment significantly blocked the ability of IP-10 to trigger the release of MIP-1alpha and MCP-1/JE. Suppressive effects of estrogen were reversed upon co-treatment with 4-hydroxytamoxifen. Estrogen treatment significantly decreased expression of proteins corresponding to the chemokine receptors CXCR3 and CCR5 on mammary cells. Exposure of female mice to IP-10 in vivo significantly decreased the ability of estrogen to support the growth of CCL-51-based tumors in mammary tissue. Our results suggest that exposure of mammary tissue to estrogen may decrease the release of local chemokines from mammary cells, potentially increasing the risk of tumor growth through decreased immune surveillance. Ongoing studies are investigating the possible mechanisms through which IP-10 stimulates the release of chemokines from mammary cells, and how the action of IP-10 may serve to decrease mammary tumor formation.

Estrogen decreases chemokine levels in murine mammary tissue: implications for the regulatory role of MIP-1 alpha and MCP-1/JE in mammary tumor formation

Estrogen contributes to the development of breast cancer through mechanisms that are not completely understood. Estrogen influences the function of immune effector cells, primarily through alterations in cytokine expression. Chemokines are proinflammatory cytokines that attract various immune cells to the site of tissue injury or inflammation, and activate many cell types, including T lymphocytes and monocytes. As an initial step toward ultimately determining whether regulation of chemokine expression and/or biological activity by estrogen could potentially be a contributing factor to the development and progression of mammary tumors, we evaluated the effect of estrogen on the expression of specific chemokines in murine mammary tissue. We also evaluated whether exposure of female mice to various chemokines could alter the growth of mammary tumors in the presence of estrogen. We report here that estrogen significantly decreases levels of the chemokines MIP-1alpha and MCP-1/JE in murine mammary tissue. Co-treatment with 4-hydroxytamoxifen partially reverses the suppressive effect of estrogen on MIP-1alpha levels. Estrogen increases the growth of CCL- 51 cell-based tumors in the mammary glands of female mice. Co-treatment with the chemokine MIP-1alpha or MCP- 1/JE substantially decreases the ability of estrogen to stimulate the formation of CCL-51 cell-based tumors. Our results show that estrogen might influence the bioactivity of specific chemokines through alteration of chemokine expression in mammary tissue, and further suggest that decreases in murine chemokines evoked by estrogen exposure could contribute to the promotion of mammary tumor growth.

Dendritic cells under investigation in autoimmune disease

Autoimmune disorders play an increasing role in public health, especially in light of the fact of the growing aged population, which primarily develop such diseases. A clear understanding of the mechanisms leading to the development of autoimmune responses and finally to autoimmune disease does not exist. Autoimmunity is characterized by the presence of autoantibodies and/or autoreactive T cells and the corresponding organ manifestation. Following the discovery of autoreactive T cells found in the periphery of mice and humans, the old immunological concept that autoreactive T cells are completely deleted in the thymus during evolution has been revised in recent years. Although antigen-presenting cells and particularly dendritic cells are known to play an important role in the regulation of immune responses and the activation of T cells, recent evidence suggests that the role of dendritic cells in the development of autoimmunity has been underestimated previously. This article aims to give a general overview on the basic immunological principles involved and gives a short review of the current literature on the functional relevance of dendritic cells in various human and murine autoimmune disorders.

Oestrogen receptor alpha gene polymorphism associates with occurrence of graft-versus-host disease and reduced survival in HLA-matched sib-allo BMT

Oestrogen receptors mediate the cellular response to oestrogens and related compounds and promote a wide range of effects on haemopoiesis. Polymorphisms of the oestrogen receptor genes have previously been associated with variation in bone mineral density, likelihood of fractures, risk of developing Alzheimer's disease, endometrial cancer and response to hormone replacement therapy. We examined the polymorphisms in both ERalpha and ERbeta genes in 108 patients receiving a bone marrow transplant from an HLA-matched sibling donor, and compared ER genotype with outcomes of occurrence of graft-versus-host disease (GVHD) and survival using logistic regression analysis. Polymorphism of ERalpha (presence of the PX haplotype (PvuII-XbaI RFLP) of intron 1), but not ERbeta, in the patient genotype associates with occurrence of acute GVHD and with lower overall survival, following correction for known clinical and genotypic risk features. Analysis of ER genotype prior to transplant might therefore inform on a patient's likelihood of developing post-transplant complications. Variation in transplant performance because of ER genotype suggests an underlying role for oestrogens in the pathophysiology of transplant-related complications, and suggests that oestrogen-related therapy may offer a new modality of post-transplant support.

Therapeutic implications of sex differences in asthma and atopy

Clear sex differences exist in asthma and atopy with a preponderance of boys before puberty. There is a reversal of this sex ratio during puberty with girls having more asthma and atopy throughout the reproductive years. Elucidating the reasons for the switch in the sex ratio should provide fresh insights into asthma and atopy with a real prospect of novel therapies for these troublesome diseases. The challenge is to match the epidemiology and physiology with the accumulating scientific knowledge on gender differences in immune responses. Hormonal changes have been implicated in the reversal of the sex ratio. Testosterone is an immunosuppressant and is likely to be protective, while female sex steroids are proinflammatory and will increase the susceptibility to atopy. Modified so as to be non-virilising/feminising, sex steroids could therefore play a useful part in modulating the immunological and inflammatory processes that underlie asthma and other allergic disorders, complementing the currently used glucocorticoid derived steroids.

Beneficial effects of the anti-oestrogen tamoxifen on systemic lupus erythematosus of (NZBxNZW)F1 female mice are associated with specific reduction of IgG3 autoantibodies

BACKGROUND

Sex hormones have been shown to influence the immune system and to modify the course of autoimmune disorders.

OBJECTIVE

To examine the effects of the oestrogen antagonist tamoxifen on the course of systemic lupus erythematosus (SLE) in (NZBxNZW)F1 mice.

METHODS

Groups of 8 week old (NZBxNZW)F1 female mice were treated with tamoxifen (800 micro g/mouse; twice a week) or with double distilled water for four months. Mice were evaluated monthly for the presence of autoantibodies directed against DNA and nuclear extract (NE) by enzyme linked immunosorbent assay (ELISA). White blood cells and thrombocytes were quantified by a cell counter and proteinuria by combistix kit. At 6 months of age, all mice that did not die spontaneously were killed and evaluated for the presence of glomerular immune deposits by indirect immunofluorescence assay. IgG isotypes of autoantibodies in the mouse sera and glomeruli were determined by gamma chain specific antibodies.

RESULTS

Tamoxifen treatment significantly reduced autoantibody production directed against either NE or DNA. The latter reduction was mainly in autoantibodies of the IgG3 isotype. Furthermore, tamoxifen had significant beneficial effects on the course of SLE in (NZBxNZW)F1 mice. At 6 months of age, 40% of the untreated mice died spontaneously, whereas all the tamoxifen treated mice were still alive. All untreated mice showed severe thrombocytopenia and persistent proteinuria, with diffuse glomerular immune deposits of IgG2a and IgG3 isotypes in their kidneys. In contrast, the tamoxifen treated mice had a normal number of thrombocytes and only minimal proteinuria. Moreover, glomerular immune deposits were detected in <40% of the tamoxifen treated mice. The latter were mainly of the IgG2a but not of the IgG3 isotype.

CONCLUSION

The results clearly show the remarkable therapeutic effects of tamoxifen on SLE of (NZBxNZW)F1 female mice and suggest that these beneficial effects are related to the specific reduction of IgG3 autoantibodies.

Regulation of the vasculature: clues from lupus

Blood vessel homeostasis involves a complex interplay between inflammatory signals, hormones, and other mediators. Recent research suggests that although atherosclerosis is primarily a problem of impaired lipid regulation, the very processes of cholesterol and triglyceride metabolism are intrinsically tied to inflammatory and hormonal regulatory signals. Similarities between inflammatory and endocrine disturbances in systemic lupus and the predicted consequences for vascular regulation help explain the high incidence of premature atherosclerosis in lupus. Atherosclerosis in systemic lupus, then, may be a consequence of imbalances in what are intrinsic homeostatic mechanisms, rather than a result of externally superimposed pathologic changes.

A synthetic peptide with estrogen-like activity derived from a phage-display peptide library

We describe a novel approach to develop peptides with estrogen like activity using a monoclonal antibody specific to estradiol (mAb E2-15) for the affinity selection of phage displayed peptides from a combinatorial peptide library. Based on the sequences of the selected phage, we synthesized a 15-mer linear peptide LPALDPTKRWFFETK which was derivatized to a 23 mer cyclic peptide CAELPALDPTKRWFFETKPPPPC. Both peptides displayed estrogen-like activity according to the following criteria:(i) in inhibiting the binding of [3H]estradiol to mAb E2-15 and to estrogen receptor (ER)alpha; (ii) in inducing transcriptional activity in MCF7 human breast cancer cells transfected with an estrogen receptor element luciferase construct and (iii) in causing an increase in creatine kinase specific activity in rat tissues in vivo. This approach can be employed to design peptide mimetic for other hormones as well.

Suppression of experimental systemic lupus erythematosus (SLE) in mice via TNF inhibition by an anti-TNFalpha monoclonal antibody and by pentoxiphylline

We have previously shown that the clinical manifestations of experimental systemic lupus erythematosus (SLE) correlate with an early increased secretion of TNFalpha and IL-1. In the present study, we examined the efficacy of two therapeutic modalities which lower TNFalpha production or activity, on the clinical manifestations of the disease. Experimental SLE was induced in naive C3H.SW mice by injection of the human anti-DNA monoclonal antibody (mAb) bearing the common idiotype, 16/6 Id. Two weeks after booster injections, treatment with either an anti-TNFalpha mAb, or pentoxiphylline (PTX) was started, for a period of 6 weeks. Production of TNFalpha (by splenocytes) and IL-1 (by peritoneal macrophages) was determined 3 and 7 months after disease induction. The experimental mice were also followed for disease manifestations. Both treatment protocols, with anti-TNFalpha mAb and with PTX, reduced the production of the two pro-inflammatory cytokines. TNFalpha and IL-1, in mice with experimental SLE. Anti-DNA antibodies were significantly lower in the mice treated with either protocol. In addition, a significantly lower rate of leukopenia, proteinuria and immune complex deposition was observed in treated mice. Abrogation of TNFalpha and IL-1 production in the early stages of experimental SLE by an anti-TNFalpha mAb or by PTX improves the clinical status of mice afflicted with this autoimmune disease.

Sex hormones as immunomodulators in health and disease

In addition to their effects on sexual differentiation and reproduction, sex hormones influence the immune system. This results in a gender dimorphism in the immune function with females having higher immunoglobulin levels and mounting stronger immune responses following immunization or infection than males. The greater immune responsiveness in females is also evident in their increased susceptibility to autoimmune diseases. However, a clear understanding of the myriad of effects that sex hormones have on the immune system is lacking. Studies in normal mice show that estrogen treatment induces polyclonal B cell activation with increased expression of autoantibodies characteristic of autoimmune diseases. Several mechanisms appear to contribute to the break in tolerance and the increase in plasma cell activity including a reduction of the mass of the bone marrow and the thymus, the emergence of sites of extramedullary hematopoiesis and altered susceptibility of B cells to cell death. In addition, sex hormone levels in both humans and experimental models correlated with the activity of their cytokine-secreting cells indicating that sex hormones influence the cytokine milieu and suggesting that altered sex hormonal levels in autoimmune patients contribute to the skewed cytokine milieu characteristic of systemic lupus erythematosus (SLE). While sex hormones alone do not cause autoimmune disease, abnormal hormone levels may provide the stage for other factors (genetic, infectious) to trigger disease. Understanding the physiology of the interaction between sex hormones and immune function and its potential pathological consequences may provide insight into the autoimmune diseases and new directions for their treatment.

Use of exogenous estrogens in systemic lupus erythematosus

OBJECTIVE

To review the current literature on the safety of using exogenous estrogens in patients with systemic lupus erythematosus (SLE).

METHOD

A MEDLINE search for articles published between 1970 and 2000 regarding the relationship between estrogens and SLE was performed. Emphasis was put on human studies, treatment trials, and epidemiologic surveys.

RESULTS

The use of exogenous estrogens in healthy women increases the risk of SLE development. For patients with established SLE, a hypoestrogenemic state appears to be protective against severe flares, whereas exogenous estrogen administration or hyperestrogenemia induced by hormonal manipulation may exacerbate the disease in certain individuals. Both the use of oral contraceptives and the use of hormonal replacement therapy (HRT) increase the chance of venous thromboembolism. The presence of antiphospholipid antibodies may aggravate the risk of thrombosis in SLE. In retrospective studies, HRT appears to be well tolerated in postmenopausal SLE patients.

CONCLUSIONS

There are no prospective data that show a deleterious effect of exogenous estrogens on disease activity in human SLE. Oral contraceptives may be considered for patients with SLE in the absence of active nephritis or antiphospholipid antibodies. The slight increase in venous thromboembolic risk should not be the chief deterrent to the use of HRT in postmenopausal SLE patients, considering its various health benefits.

Non-steroidal anti-oestrogens inhibit the differentiation of synovial macrophages into dendritic cells

BACKGROUND

Dendritic cells (DC) have been suggested to play an important role in the pathogenesis of rheumatoid arthritis (RA). Agents that inhibit DC differentiation and function may have a therapeutic value in the treatment of RA.

OBJECTIVE

To examine the effect of the non-steroidal anti-oestrogens toremifene and tamoxifen on the differentiation of synovial fluid (SF) macrophages into DC.

METHODS

SF macrophages from patients with RA were cultured with interleukin (IL)-4 and granulocyte/macrophage colony-stimulating factor (GM-CSF) in the presence or absence of anti-oestrogens. The expression of cell surface markers on SF antigen-presenting cells (APC) was studied by flow cytometry. The capacity of SF APC to stimulate allogeneic T cells was studied using the mixed lymphocyte reaction. The production of tumour necrosis factor-alpha, IL-10 and transforming growth factor-beta1 was studied using ELISA.

RESULTS

Anti-oestrogens inhibited the differentiation of SF macrophages into DC and the capacity of SF macrophage-derived DC to stimulate allogeneic T cells.

CONCLUSIONS

By inhibiting the differentiation of SF macrophages into DC, non-steroidal anti-oestrogens may have beneficial effects in RA.

The mechanism by which a peptide based on complementarity-determining region-1 of a pathogenic anti-DNA auto-Ab ameliorates experimental systemic lupus erythematosus

A peptide based on complementarity-determining region (CDR)-1 of a monoclonal murine anti-DNA Ab that bears the common idiotype, 16/6Id, was synthesized and characterized. The peptide, designated pCDR1, was found to be an immunodominant T-cell epitope in BALB/c mice. The CDR1-based peptide was shown to be capable of inhibiting the in vivo priming of BALB/c mice immunized with the peptide or with the whole anti-DNA 16/6Id(+) mAbs of either mouse or human origin. We show here that administration of pCDR1 (weekly, i.v., 100 microgram/mouse) in aqueous solution for 5 weeks starting at the time of disease induction with the human 16/6Id prevented the development of clinical manifestations of experimental systemic lupus erythematosus (SLE). Further, 10 weekly injections of pCDR1 to BALB/c mice with an established experimental SLE down-regulated clinical manifestations of SLE (e.g., anti-DNA auto-Abs, leukopenia, proteinuria, immune complex deposits in the kidneys) in the treated mice. Prevention of SLE induction was shown to be associated mainly with a decrease in the levels of IL-2, INFgamma, and the proinflammatory cytokine TNFalpha. On the other hand, the secretion of the immunosuppressive cytokine TGFbeta was elevated. Amelioration of the clinical manifestations of an already established experimental SLE correlated with a dramatic decrease in TNFalpha secretion, elevated levels of TGFbeta, and immunomodulation of the Th1 and Th2 type cytokines to levels close to those observed in healthy mice.

Molecular analysis of estrogen receptor alpha and beta in lupus patients

BACKGROUND

In female patients with systemic lupus erythematosus (SLE), we identified estrogen receptor ERa, ERb and ERa variant transcripts in peripheral blood mononuclear cells (PBMC). Exon 1 and 2 of ERa gene was subjected to mutation analysis to assess whether possible nucleotide alterations are linked to the disease.

METHODS

The whole coding sequence of ERa was analysed by reverse transcription polymerase chain reaction (RT-PCR) and cDNA sequencing in PBMC prepared from 19 SLE patients and 12 healthy females. ERa exon 1 and exon 2 were subjected to mutation analysis using DNA isolated from whole blood of 21 SLE patients and 29 healthy females. The aminoterminal coding sequence of ERb was also analysed by RT-PCR.

RESULTS

Wild type ERa and ERa splicing variants with deletions in exons 2, 5 and 7 were detected both in healthy individuals and in SLE patients, with no qualitative difference in their expression among the two populations. In ERa exon 1, the polymorphisms identified codon 10 and codon 87, both in patients and in healthy individuals who were not associated with the disease. No other mutations were present in ERa exon 1 or ERa exon 2 in all subjects studied. ERb was expressed in both populations.

CONCLUSION

PBMC of SLE patients express wild type ERa, ERb and the same ERa variants as do healthy individuals. Genetic alterations in exon 1 and exon 2 of the ERa gene are not linked with SLE disease.

Sex hormones and systemic lupus erythematosus

Lupus is one disease in which sex hormones and gender are quite important. Studies of autoimmune diseases like lupus have made the hormone connection more important and increased our overall understanding of the sexual dimorphism of the immune system. It is clear that some fundamental biologic mechanism is at work here and that only knowledge of the molecular mechanisms behind the action of the hormones can help us to understand the gender preference in this illness. Hormones may be potent regulators of cytokine levels and, consequently, disease activity.

The immune system as a potential target for environmental estrogens (endocrine disrupters): a new emerging field

It is now well known that natural (17beta-estradiol) and synthetic (e.g. diethylstilbestrol) estrogens not only affect the reproductive system, but also markedly influence the immune system. Recently, a new class of estrogens that is abundant in the environment (in industrial chemicals, pesticides, and surfactants) has been recognized. Some of these estrogenic chemicals (which are a large subgroup of endocrine disrupters) have also been shown to influence the immune system. This review assimilates growing evidence in wildlife, laboratory animals and to a limited extent in humans, which suggests that environmental chemicals may also affect the immune system. Further studies are needed to ascertain the immunological consequences of exposure to environmental estrogens, especially in humans. At the present time, it is not known whether the human immune system responds to a low dose of environmental estrogens or if environmental estrogens influence certain subsets of human populations, rather than the general population. Conceivably, an alteration of the immune system by environmental estrogens could affect the individuals' ability to mount well-regulated immune responses to microbial and vaccine antigens, allergens, self and tumor antigens. Possible changes in the immune system must be investigated routinely in toxicity studies. A comprehensive mechanistic understanding of potential immunomodulatory chemicals is needed. In this regard, relevant laboratory animals may be especially useful in identifying susceptible periods of life, whether both genders are equally affected, in analysis of changes in target lymphoid organs, and to determine the immunological effects of mixtures of chemicals.

Altered bone marrow cell sensitivity in the lupus-prone NZB/W mouse: regulation of CFU-GM colony formation by estrogen, tamoxifen and thrombopoietin

Estrogen is thought to contribute to the onset of systemic lupus erythematosus (SLE) in women through mechanisms that are not completely understood. Although estrogen serves as a negative regulator in normal hematopoietic development, little research has been conducted examining alteration in hematopoietic development triggered by estrogen in lupus-susceptible individuals. We examined whether estrogen and other factors could influence colony formation of bone marrow cells obtained from normal and lupus-susceptible mice. Bone marrow cells isolated from New Zealand Black (NZB) and lupus-prone New Zealand Black and New Zealand White cross (NZB/W) mice were cultured in the presence of granulocyte-macrophage colony stimulating factor (GM-CSF) alone or in combination with estrogen, thrombopoietin (TPO), tamoxifen, estrogen and TPO. or estrogen and tamoxifen, and plated in methylcellulose culture medium. Plates were scored for the number of CFU-GM (colony forming unit granulocyte-macrophage) colonies after 6d in culture. For females of both mouse strains, estrogen significantly decreased (P < 0.05) the number of GM colonies. Co-treatment of NZB/W cells, but not NZB cells, with TPO or tamoxifen reversed the suppressive action of estrogen (P < 0.05). In contrast, while estrogen did suppress colony formation from cells of NZB/W males (P < 0.05), neither TPO nor tamoxifen reversed this effect. Our results indicate that the sensitivity of bone marrow cells isolated from both female and male NZB/W lupus-prone mice to hormones/growth factors is qualitatively different from cells of NZB mice, and suggest that hematopoietic alterations at the level of the bone marrow may be related to the pathogenesis of SLE.