The expression of cytokines and chemokines in the blood of patients with severe weight loss from anorexia nervosa: an exploratory study.

Anorexia nervosa (AN) is a serious, potentially life-threatening disorder characterized by severe weight loss, dysregulated eating, and often excessive exercise. While psychiatric illnesses such as depression are associated with increased levels of pro-inflammatory mediators, evidence for such disturbances in patients with AN has been less clear. In an exploratory study of possible disturbances in immune responses in AN, we assayed a panel of cytokines and chemokines in the blood of patients undergoing inpatient treatment, testing the hypothesis that metabolic disturbances in this disease would lead to a pattern of immune disturbances distinct from that of other psychiatric diseases. For this purpose, we evaluated patients by the Beck Depression Inventory-II (BDI-II) and the Eating Disorders Examination-Questionnaire and assessed cytokines and chemokines by enzyme-linked immunosorbent assays. Patients reported a moderate level of depression (mean BDI-II = 22.6) but exhibited few immunologic abnormalities of the kind associated with major depressive disorder [e.g., increased interleukin (IL)-6]; RANTES showed the most frequent elevations and was increased in 4 of the patients studied. Together, these findings suggest that features of AN such as loss of adipose tissue and excessive exercise may attenuate cytokine production and thus modulate the experience of illness that impacts on core features of disease.

Vaccination of patients with auto-immune inflammatory rheumatic diseases requires careful benefit-risk assessment.

Will vaccination raise the incidence of autoimmune diseases, what is the impact of increasingly crowded vaccination schedules, the vaccination in age groups and the risk of coincidental temporal association? All these issues are still under debate. However, for the time being, to avoid confusion in the medical community and the media, we have to adhere to guidelines established consensually by experts while ensuring a strict surveillance and reporting possible side effects. Recommendation for vaccination in patients with autoimmune inflammatory rheumatic diseases (AIIRD) based on the currently available evidence and expert opinion were recently formulated by an EULAR task force. Major recommendations for AIIRD include: i) vaccination should ideally be administered during stable disease; ii) influenza vaccination and pneumococcal vaccination should be strongly considered; iii) vaccination can be administered during the use of DMARDs and TNF-inhibitors, but before starting rituximab; iv) live attenuated vaccines should be avoided whenever possible in immunosuppressed patients; v) BCG vaccination is not recommended.

Molecular pathways involved in synovial cell inflammation and tumoral proliferation in diffuse pigmented villonodular synovitis.

Diffuse-type tenosynovial giant cell tumors, also known as pigmented villonodular synovitis, are unique mesenchymal lesions that arise from the synovial tissue of the joints. They are predominantly intraarticular, aggressive, infiltrative processes, characterized by both inflammatory or neoplastic properties and local destructive progression. The pattern of synovial gene and protein expressions in pigmented villonodular synovitis, similar to those in activated macrophages in rheumatoid arthritis, and the phenotype of multinucleated giant cells, characteristic of osteoclasts, suggest that there is a common autocrine mechanism in osteoclast differentiation in both diseases and indicate the potential utility of tumor necrosis factor (TNF)-alpha blockade. High synovial colony stimulating factor 1 (CSF1) messenger RNA (m RNA) expression in pigmented villonodular synovitis, unrelated to a chromosomal translocation involving CSF1 locus, may indicate that there is a synergic paracrine loop mediated by TNF-alpha and CSF1, as shown in both inflammatory and neoplastic conditions. The effects of a new therapeutic approach consisting in intraarticular TNF-alpha blockade were studied in four pigmented villonodular synovitis knees. Knee injections produced a rapid reduction in clinical and sonographic indexes and immunohistological alterations, confirmed by arthroscopic synovectomy. A delayed relapse in one of the four knees and unaltered synovial CSF1 expression were other important findings. In the light of these observations, CSF1/CSF1R interaction probably represents a more sensible therapeutic target than TNF-alpha blockade in the diffuse form of pigmented villonodular synovitis.

[HDL inhibit cytokine production in a mouse model of urate crystal-induced inflammation]. / Le HDL inibiscono la produzione di citochine nel modello murino di infiammazione da microcristalli di urato monosodico.

OBJECTIVES: To evaluate whether high density lipoproteins (HDL) affect monosodium urate (MSU) crystal-induced inflammation in the murine air pouch model. METHODS: MSU crystals were prepared by Denko's method and sterilized by heating at 180°C for 2 h before each experiment. Human HDL were isolated from peripheral blood of healthy volunteers. MSU crystals (2 mg in 1 ml of PBS) were injected into subcutaneous air pouches in mice in the presence or absence of HDL (0.1 mg). Negative control pouches received 1 ml of PBS. To recover pouch fluid, the pouches were washed with 2 ml of PBS after the animals were sacrificed. The leukocyte count in the lavage fluids was obtained using a hemocytometer and differential leukocyte count was determined by May-Grunwald-Giemsa staining. IL-6, KC, CCL2 and TNF-α levels were measured in exudates by ELISA. RESULTS: MSU crystals increased the number of leukocytes and the neutrophil migration, as well as the concentrations of IL-6, KC and CCL2 in pouch fluids, while the TNF-α levels were not detectable. The treatment with HDL led to a reduction in all inflammatory parameters: the leukocyte count decreased by 73%; the neutrophil density decreased by 35%; the IL-6, KC and CCL2 concentration decreased by 4-, 6- and 5-fold respectively. CONCLUSIONS: This study shows that HDL may limit the inflammatory process by inhibiting leukocyte recruitment and cytokine release. HDL are likely to represent a mechanism of control of crystal-induced inflammation.

Apolipoprotein A-I and cholesterol in synovial fluid of patients with rheumatoid arthritis, psoriatic arthritis and osteoarthritis.

OBJECTIVE: To investigate lipid and apolipoprotein (Apo) levels in synovial fluid (SF) and serum of patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and osteoarthritis (OA). METHODS: SF of 44 patients (14 RA, 14 PsA, 16 OA) was tested for Apo A-I, HDL-C, total cholesterol (TC), IL-1Beta, TNF-alpha, white blood cell count (WBC) and polymorphonucleate (PMN) percentage. Blood samples, collected simultaneously to the SF, were examined for Apo A-I, HDL-C, TC, TNF-alpha, serum amyloid A (SAA) and C-reactive protein (CRP). Thirty-three healthy donors served as a control group. RESULTS: Serum levels of Apo A-I, HDL-C and TC were higher in OA as compared with RA, PsA and the control group. The patients with inflammatory arthritis had lower serum levels of Apo A-I and HDL-C than did the controls. Apo A-I concentrations were higher in SF of RA patients, while PsA showed the highest concentration of TC, though not reaching statistical significance. A negative correlation was found between serum Apo A-I and synovial WBC (r=-0.48 p=0.002) and IL-1Beta (r=-0.42 p=0.016). There was a strong positive correlation between the Apo A-I SF/serum ratio and synovial WBC (r=0.73 p<0.001), IL-1Beta (r=0.68 p<0.001) and a weak, yet significant, correlation with serum CRP (r=0.49 p=0.002) and SAA (r=0.41 p=0.008). CONCLUSION: Our study confirms that in RA Apo A-I and TC levels are decreased in plasma and increased in SF, thus suggesting infiltration of HDL particles in the inflamed joint with inhibition of the local production of proinflammatory cytokines. On the other hand, it can be hypothesized that the sequestration of Apo A-I in the inflamed tissue may, in part, account for the reduction of circulating HDL and the excess cardiovascular risk in RA and PsA patients.

Gender-based dimorphic pattern for interleukin-1 receptor antagonist in type 2 diabetes mellitus.

UNLABELLED: Adipose tissue secretes a variety of cytokines, some of which are increased in the serum of obese patients. The anti-inflammatory interleukin-1 receptor antagonist (IL-1Ra) is the most highly elevated known cytokine in human obesity, and its serum levels are strongly associated with the degree of insulin resistance in non-diabetic patients. AIM: The present study examined serum levels of IL-1Ra in type 2 diabetic patients (T2DM) and their relationships with three other adipokines (leptin, interleukin-6 [IL-6], adiponectin). Their correlation with anthropometric and biochemical variables was examined, as well as their intraindividual fluctuations. METHODS: Fifty T2DM patients, aged 58+/-13 years, were consecutively recruited among those electively hospitalized for a one-week intensive training course with our Diabetes Education Service. Anthropometric measurements and blood samples were taken after an overnight fast on admission (baseline) and after four days. RESULTS: Mean serum levels of IL-1Ra and leptin, but not of IL-6 and adiponectin, were significantly higher in women than in men (P<0.0006), and this difference persisted after correction for body mass index (BMI) (P<0.0004). In addition, IL-1Ra and leptin were strongly correlated with the BMI (P<0.0004). By contrast, no significant correlations were observed between IL-1Ra and glucose-control parameters. Finally, all four adipokines exhibited wide interindividual variability, but with limited intraindividual fluctuations over the short time period. CONCLUSION: IL-1Ra, leptin and adiponectin serum levels exhibit marked interindividual variation with high intraindividual consistency. A gender-based dimorphic pattern for IL-1Ra, independent of the degree of adiposity and glucose control, was also found.

Anti-fibroblast antibodies detected by cell-based ELISA in systemic sclerosis enhance the collagenolytic activity and matrix metalloproteinase-1 production in dermal fibroblasts.

OBJECTIVES: Antibodies binding to the surface of fibroblasts (anti-fibroblast antibodies: AFA) have been described in systemic sclerosis (SSc). We aimed to assess the effect of AFA on extracellular matrix (ECM) turnover and whether AFA were associated with anti-topoisomerase-I antibody. METHODS: IgG were purified from AFA-positive and AFA-negative sera selected within 20 SSc and 20 healthy individuals, and tested on normal dermal fibroblasts, at protein and mRNA level, for their capacity to induce collagen deposition or degradation. RESULTS: Fibroblasts stimulated with AFA-positive but not with AFA-negative and control IgG showed an increased capacity to digest collagen matrix and produce metalloproteinase-1 (MMP-1) while their production of total collagen, type I collagen and tissue inhibitor of metalloproteinase-1 (TIMP-1) was unaffected. The steady-state mRNA levels of MMP-1, COL1A1 and TIMP-1 paralleled the protein levels. AFA-positive IgG did not induce Smad 2/3 phosphorylation, indicating that this transforming growth factor-beta signalling pathway was not involved. IL-1 and tumour necrosis factor (TNF) neutralization did not reverse the enhanced production of MMP-1, suggesting a direct effect of AFA on fibroblasts. Finally, anti-topoisomerase-I antibodies were present in 11 of 12 AFA-negative IgG, and an anti-topoisomerase-I monoclonal antibody failed to enhance MMP-1 production, thus indicating a lack of correlation between AFA and anti-topoisomerase-I antibody. CONCLUSIONS: These results indicate that SSc antibodies binding to fibroblasts enhance matrix degradation and MMP production events that may favour inflammation but do not directly impact on fibrosis development.

Interleukin-1 receptor antagonist is upregulated during diet-induced obesity and regulates insulin sensitivity in rodents.

AIMS/HYPOTHESIS: The IL-1 receptor antagonist (IL-1Ra) is an anti-inflammatory cytokine known to antagonise the actions of IL-1. We have previously shown that IL-1Ra is markedly upregulated in the serum of obese patients, is correlated with BMI and insulin resistance, and is overexpressed in the white adipose tissue (WAT) of obese humans. The aim of this study was to examine the role of IL-1Ra in the regulation of glucose homeostasis in rodents. METHODS: We assessed the expression of genes related to IL-1 signalling in the WAT of mice fed a high-fat diet, as well as the effect of Il1rn (the gene for IL-1Ra) deletion and treatment with IL-1Ra on glucose homeostasis in rodents. RESULTS: We show that the expression of Il1rn and the gene encoding the inhibitory type II IL-1 receptor was upregulated in diet-induced obesity. The blood insulin:glucose ratio was significantly lower in Il1rn ( -/- )animals, which is compatible with an increased sensitivity to insulin, reinforced by the fact that the insulin content and pancreatic islet morphology of Il1rn ( -/- ) animals were normal. In contrast, the administration of IL-1Ra to normal rats for 5 days led to a decrease in the whole-body glucose disposal due to a selective decrease in muscle-specific glucose uptake. CONCLUSIONS/INTERPRETATION: The expression of genes encoding inhibitors of IL-1 signalling is upregulated in the WAT of mice with diet-induced obesity, and IL-1Ra reduces insulin sensitivity in rats through a muscle-specific decrease in glucose uptake. These results suggest that the markedly increased levels of IL-1Ra in human obesity might contribute to the development of insulin resistance.

Is there a rationale to using leflunomide in early rheumatoid arthritis?

The efficacy of leflunomide in the treatment of early rheumatoid arthritis (RA) patients might be attributed to the fact that it acts at several levels, including the anti-inflammatory and anti-destructive pathways. This is in addition to its inhibition of the L-dihydro-orotate dehydrogenase (DHOH) enzyme and pyrimidine de novo synthesis which decreases cell proliferation and more specifically early activated CD4+ T cells, as well as monocyte interaction with T cells leading to cytokine and anticytokine production. Recent studies clearly indicate the rationale of an early administration of leflunomide in RA patients, particularly in the light of the results of previously reported clinical studies showing its rapid onset of action when compared to other DMARDs. The early efficacy and safety of leflunomide in patients with early RA is sustained over a long period, and the long-term safety profile of leflunomide does not seem to be different from that observed in phase III trials.

[Sport and immuno-allergology]. / Sport et immuno-allergologie.

In the past years, the importance of sports in everyday life has been increasing rapidly. Rhinitis and asthma account for the most common problems encountered by sport physicians. These pathologies are often linked to atopy and will require an investigation by an allergist. Less frequent, cholinergic urticaria and exercice-induced anaphylaxis require special attention as to therapeutics. Infections of the upper respiratory tract constitute a well-known problem in athletes. In numerous studies attempts were made to correlate susceptibility to infections to the immunological modifications occurring during exercise. Recently, the use of objective methods has made it possible to analyse these aspects and to demonstrate that other factors also affect immunological changes triggered by exercise.

Synovial tissue interleukin-18 expression and the response to treatment in patients with inflammatory arthritis.

OBJECTIVE: To measure synovial tissue interleukin-18 (IL-18) expression in patients with inflammatory arthritis, and to identify associations with serum levels, disease activity, and response to treatment. METHODS: Synovial tissue biopsies and serum samples were obtained from patients with early, active, rheumatoid arthritis (RA) (n = 12), undifferentiated seronegative arthritis (SnA) (n = 9), psoriatic arthritis (PsA) (n = 5), and reactive arthritis (ReA) (n = 2) before and one year after introduction of disease modifying antirheumatic drug (DMARD) treatment. Osteoarthritis (OA) tissues were compared. Tissue IL-18 expression was determined after immunohistochemical staining using a semiquantitative scale. Serum IL-18 was measured by enzyme linked immunosorbent assay. RESULTS: Before treatment was started, tissue IL-18 expression was increased in each diagnostic group compared with OA (p<0.05). Tissue IL-18 expression was correlated with serum C reactive protein levels (r = 0.53, p = 0.003) but not with serum IL-18. After DMARD treatment, 12 patients (five RA, four SnA, three PsA) were re-evaluated. Decreases in tissue IL-18 expression were observed in eight, although the trend did not reach significance (p = 0.068). Changes in tissue IL-18 expression were correlated with changes in serum IL-18 (r = 0.62, p = 0.041) and C reactive protein (r = 0.72, p = 0.009). CONCLUSIONS: Synovial tissue IL-18 expression was correlated with disease activity in inflammatory arthritis. After treatment, tissue levels changed in parallel with changes in serum IL-18 and with changes in the acute phase response. These observations support a role for IL-18 in the pathophysiology of inflammatory arthritis.

[Biological modulation of IL-1 activity: role and development of its natural inhibitor IL-1Ra]. / Modulazione biologica dell'attività di IL-1: ruolo dell'inibitore naturale IL-1Ra e suo sviluppo.

IL-1 and TNF-alpha are potent inducers of matrix metalloproteinases (MMP), eicosanoids, nitric oxide oxydase (iNOS), receptor activator of NF-kB ligand (RANKL), products involved in the destruction of the extracellular matrix, the cartilage and in bone resorption. IL-1, particularly important at the local level, is more potent than TNF-alpha in stimulating MMP and specifically in impeding cartilage repair. However, IL-1 and TNF-alpha strongly synergize in multiple biological functions. Blockade of IL-1 by IL-1 receptor antagonist (IL-1Ra, sIL-1RII) in combination with the soluble IL-1 accessory protein (IL-1R AcP) result in a long-term beneficial effect in chronic inflammatory diseases. The association with anti-TNF-alpha therapy may also represent a logical approach, considering the number of patients that do not respond to either compound alone.

The pivotal role of interleukin-1 in the clinical manifestations of rheumatoid arthritis.

The role of the cytokine network in mediating inflammation and joint destruction in rheumatoid arthritis (RA) has been investigated extensively in recent years. Interleukin-1 (IL-1) and tumour necrosis factor alpha (TNFalpha) are two pivotal proinflammatory cytokines that have been shown to contribute to the clinical manifestations of RA. The ability of IL-1 to drive inflammation and joint erosion and to inhibit tissue repair processes has been clearly established in in vitro systems and animal models. Under physiological conditions, the activity of IL-1 is balanced by IL-1 receptor antagonist (IL-1R alpha). Understanding of the respective roles of IL-1 and IL-1R alpha in conditions of health and disease has led to the development of a recombinant IL-1ra, anakinra (Kineret; Amgen Inc., Thousand Oaks, CA), which offers a new therapeutic modality for RA.

The active metabolite of leflunomide, A77 1726, inhibits the production of prostaglandin E(2), matrix metalloproteinase 1 and interleukin 6 in human fibroblast-like synoviocytes.

OBJECTIVES: To investigate the effects of the active metabolite of leflunomide, A77 1726, on fibroblast-like synoviocytes. In rheumatoid arthritis (RA) synoviocytes participate in tissue destruction by producing metalloproteinases (MMP), prostaglandin E(2) (PGE(2)) and interleukin (IL) 6, which are involved in extracellular matrix degradation, resorption of the mineral phase and osteoclast-mediated bone resorption. METHODS: Human synoviocytes were stimulated with IL-1alpha or tumour necrosis factor alpha (TNF-alpha) in the presence of A77 1726. Culture supernatants were analysed for production of interstitial collagenase (MMP-1), tissue-inhibitor of metalloproteinases 1 (TIMP-1), PGE(2) and IL-6. Total RNA was isolated and analysed for steady-state levels of MMP-1, cyclooxygenase-2 (COX-2) and IL-6 mRNA. RESULTS: A77 1726 inhibited the production of PGE(2) in synoviocytes activated by TNF-alpha and IL-1alpha with median inhibitory concentrations (IC(50)) of 7 and 3 microM respectively. In contrast, MMP-1 and IL-6 production was inhibited at high A77 1726 concentrations (> 10 microM), whereas TIMP-1 was not affected. The inhibition of MMP-1 and IL-6 production was due to the known inhibitory effect of A77 1726 on pyrimidine synthesis, as it was reversed by the addition of uridine. This did not apply to PGE(2) production, which was inhibited via direct action of A77 1726 on COX-2, as shown by the increasing amount of substrate (arachidonic acid) in the culture medium. CONCLUSION: This study shows that some of the beneficial effect of leflunomide in RA patients may be due to the inhibition of PGE(2), IL-6 and MMP-1 production in synoviocytes. This effect, coupled with its multiple inhibitory effects on T lymphocyte functions, might account for the significant reduction in the rate of disease progression in RA patients treated with leflunomide.

Serum interleukin 18 and interleukin 18 binding protein in rheumatoid arthritis.

OBJECTIVE: To measure serum interleukin 18 (IL18) and IL18 binding protein (IL18BP) levels in patients with inflammatory arthropathies, and to identify associations with disease status and the response to treatment. METHODS: Serum samples were obtained before and after methotrexate treatment from patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA) attending an early arthritis clinic. IL18 and IL18BP were measured by enzyme linked immunosorbent assay (ELISA). RESULTS: Sixty patients with RA and 13 with PsA were evaluated. Serum IL18 levels were significantly higher in RA than in PsA (p<0.001). After six months' treatment with methotrexate, IL18 levels were reduced, but the differences were not significant (p=0.052). In cross sectional analyses, no correlations between IL18 levels and measures of disease activity or structural damage in RA were found. In longitudinal analyses, no correlations between IL18 levels and the response to treatment or the degree of progressive joint damage were found. Similarly, IL18BP levels were raised in RA, and were not associated with measures of the clinical status or the response to treatment. CONCLUSION: Raised serum levels of IL18 are consistent with a pathophysiological role in RA. However, in this study measurement of circulating IL18 and IL18BP did not correlate significantly with clinical measures of disease activity or the response to treatment in patients with early RA.

Differential regulation of MMP-1/9 and TIMP-1 secretion in human monocytic cells in response to Mycobacterium tuberculosis.

In tuberculosis, matrix metalloproteinase (MMP) secretion is involved in leukocyte migration to sites of infection but in excess may contribute to tissue destruction. We demonstrate that human monocytic THP-1 cells and primary monocytes secrete MMP-1 (52 kD collagenase) when phagocytosing live, virulent M. tuberculosis but not inert latex. The magnitude of MMP-1 secretion was approximately 10-fold less when compared to MMP-9 (92 kD gelatinase) secretion. MMP-1 secretion was also relatively delayed (detected at 24 h vs. 4 h). M. tuberculosis, zymosan or latex stimulate similar TIMP-1 secretion within 8 h and increasing over 24 h. MMP-1/9 secretion was decreased by inhibitors of protein kinase (PK) C, PKA or tyrosine kinases (PTK) in a concentration-dependent manner. In contrast, TIMP-1 secretion was not affected by PKC or PTK blockade and only somewhat reduced by high level PKA inhibition. In summary, M. tuberculosis-infected monocytes secrete MMP-1 at lower concentrations than MMP-9 and such MMP secretion is regulated by multiple upstream signalling pathways which do not control TIMP-1 secretion. Divergent effects of i on MMP and TIMP secretion from monocytes may be important in influencing matrix degradation in vivo.

Evidence for the biological modulation of IL-1 activity: the role of IL-1Ra.

Interleukin-1 (IL-1) and tumor necrosis factor (TNFalpha) are key mediators of inflammation and are produced by monocyte-macrophages (Mphi) following the activation of soluble factors and contact with stimulated Th1 lymphocytes. The contact between lymphocytes and Mphi is regulated by ligand and counterligands (i.e. beta2-integrins, CD40-CD40L, CD69) and plasma lipoproteins (i.e. HDL-associated Apo-AI). IL-1 and TNFalpha are potent inducers of matrix metalloproteinases (MMPs), eicosanoids, nitric oxide oxydase (iNOS), receptor activator of NF-kappaB ligand (RANKL), products involved in the destruction of the extracellular matrix, the cartilage and in bone resorption. IL-1--particularly important at the local level--is more potent than TNF in stimulating MMPs and specifically in impeding cartilage repair. However, IL-1 and TNFalpha strongly synergize in multiple biological functions. Blockade of IL-1 by IL-1 receptor antagonist (IL-1Ra, sIL-1RII) in combination with the soluble IL-1 accessory protein (IL-1R AcP) result in a long-term beneficial effect in chronic inflammatory diseases. The association with anti-TNF therapy may also represent a logical approach, considering the number of patients that do not respond to either compound alone. An altogether new challenge would be to accomplish the blockade at a more proximal level (i.e. lymphocyte/Mphi interaction).

Phorbol diester 12-O-tetradecanoylphorbol 13-acetate (TPA) up-regulates the expression of estrogen receptors in human THP-1 leukemia cells.

In the present work, we have inspected expression of estrogen receptors (ER) and their regulation by the phorbol diester 12-O-tetradecanoylphorbol 13-acetate (TPA) in a leukemic cell line, the THP-1 cells, using multiple experimental approaches. Firstly, ligand binding assay (LBA) revealed that control (unstimulated) THP-1 cells express type I (high affinity, limited capacity) ER in the nuclear fraction only, whilst treatment of cells with TPA resulted in the appearance of type I ER in the soluble fraction as well, with the 50 ng/ml dose and the 48 h incubation time being the most effective experimental condition. A concomitant increase of type II ER was also seen in both soluble and nuclear cell fractions. Unstimulated THP-1 cells were found to be ER negative by immunocytochemistry; conversely, cells exposed to 50 ng/ml TPA for 48 h stained positively for ER, with the majority of cells having a strong nuclear staining. Scrutiny of ER mRNA expression using reverse transcriptase-polymerase chain reaction showed the presence of a wild type ER transcript in both control and TPA-treated THP-1 cells, though levels of ER mRNA were found to be comparatively higher in the latter. This combined evidence would imply that the TPA-induced differentiation of THP-1 cells is accompanied by the rise of high affinity (type I) ER, suggesting that estrogens may play a role in the regulation of macrophage activity during the inflammatory and/or the immune response.