Humoral Response to Hepatitis B and COVID-19 Vaccine among Maintenance Hemodialysis Patients.

Maintenance hemodialysis (MHD) patients have impaired immunological responses to pathogens and vaccines. In this study, we compared the humoral response to HBV and COVID-19 vaccines in a cohort of MHD patients. Demographic and clinical characteristics of vaccine responders and non-responders were also compared, and the association between the humoral responses to both vaccines was evaluated. The cohort included 94 MHD patients who were vaccinated at least once for HBV and twice for COVID-19. Among the 94 patients, 28 (29.8%) did not develop protective titers to HBV. Hypertension, coronary heart disease, and heart failure were more common in non-responders. Among MHD patients, 85% had positive IgG anti-spike SARS-CoV-2 levels 6 months after two doses of BNT162b2 (Pfizer/Biotech) vaccine. Age and immunosuppressive therapy were the main predictors of humoral response to COVID-19 vaccine. We did not find any association between non-responders to HBV and non-responders to COVID-19 vaccine. There was no difference in IgG anti-spike titers between HBV responders and non-responders (505 ± 644 vs. 504 ± 781, p = 0.9) Our results suggest that reduced humoral response to hepatitis B is not associated with reduced response to COVID-19 vaccine. Different risk-factors were associated with poor immune response to HBV and to COVID-19 vaccines.

Elevated Serum Levels of IgG4 in Patients with Heart Failure with Reduced Ejection Fraction: A Prospective Controlled Study.

(1) Background: Immunoglobulin gamma subclass 4 (IgG4) is a serum protein belonging to the immunoglobulin superfamily. It has a central role in certain immune-mediated conditions defined as IgG4-related disease. There is a paucity of data regarding the potential association of IgG4 and cardiovascular diseases. Our aim is to study the serum levels of IgG4 in patients with ischemic and non-ischemic dilated cardiomyopathy (DCM). (2) Methods: patients with ischemic and non-ischemic DCM were included in this study. Non-ischemic DCM was defined as a left ventricular ejection fraction (LVEF) < 40% without coronary artery disease (CAD). Ischemic DCM was defined as a LVEF < 40% and proven CAD. The serum concentrations of IgG4 were measured by turbidimetry. (3) Results: Overall 98 patients with cardiomyopathy had significantly higher levels of IgG4 compared with the control group (77.4 ± 64.0 vs. 50.3 ± 28.8 mg/dL, p < 0.01). Although there was no difference in the total IgG levels in patients with ischemic DCM, the serum concentrations of IgG4 were significantly higher than the corresponding values in the control group (89.8 ± 67.3 vs. 50.3 ± 28.8 mg/dL; interquartile ranges: 40.4−126.5 vs. 31.8−66.8 mg/dL, p < 0.01). This was altered by gender and smoking. (4) Conclusions: The patients with ischemic DCM had increased serum concentrations of IgG4. Future studies are warranted to explore the potential role of an IgG4-mediated process in patients with heart failure with reduced LVEF.

A prospective study of C-reactive protein in patients with obesity during IVF.

This prospective cohort pilot study investigated the physiology of C-reactive protein (CRP) during in vitro fertilization (IVF) cycles and its effect on outcomes in women with and without obesity. The study was conducted from April to August 2014, in the IVF Unit of a university-affiliated hospital. Women aged 18-42 years were enrolled. Those with chronic inflammatory diseases or acute illness were excluded. A total of 31 patients were included: 17 with BMI < 30 kg/m2 and 14 with BMI ≥ 30 kg/m2. Serum CRP levels were measured: (i) before starting ovarian stimulation; (ii) on the day of ß-HCG administration; and (iii) on day of ovum pick-up (OPU), in both serum and follicular fluid. Serum CRP levels were significantly higher in women with obesity at all time points. For the entire cohort, a positive correlation was found between basal oestradiol (E2) and basal CRP (r = 0.71, p < 0.05). A specific pattern of CRP levels was not detected during the IVF cycle. High serum CRP levels on OPU day had a negative effect on embryo quality (p = 0.056). CRP ≥ 0.5 mg/dL was associated with lower quality embryos (2.6 ± 0.3 vs. 3.3 ± 0.3; p = 0.04). High serum CRP level on OPU day negatively affects embryo quality.

Induction of labor, and physiological and psychological stress responses as expressed by salivary cortisol: a prospective study.

PURPOSE: To describe patterns of physiological and psychological stress during induced labor and their correlation to obstetrical and neonatal outcomes. METHODS: This prospective, observational study included 167 women, with low-risk, singleton pregnancies, who delivered at term, at a tertiary academic center from 2015 through 2018. Among them, 72 (43%) underwent induction and 95 (57%) had spontaneous labor onset. Physiological stress was evaluated by salivary cortisol measurements and emotional stress by questionnaires (visual analogue stress scale 0-10) during latent phase, active phase and full dilation stages of labor, as well as 2 min and 2 h postpartum. Cord blood cortisol and pH were obtained. Stress patterns were compared between parturients who did or did not undergo induction. Modes of delivery, labor and delivery complications, and early neonatal outcomes were compared. Mothers completed the Hospital Anxiety and Depression Scale. RESULTS: Induced women had lower cortisol concentrations during the latent phase compared to spontaneous onset of labor (p = 0.003), with no differences during active (p = 0.237), full dilation (0.668), 2 min and 2 h after delivery (p = 0.666). Stress scale and Hospital Anxiety and Depression Scale scores were similar between groups. Cord cortisol (p = 0.294), 1-min Apgar score ≤ 7 (p = 0.502) and 5-min Apgar score ≤ 7 (p = 0.37) were similar. All had cord pH > 7. CONCLUSIONS: Induction does not increase stress during labor. Moreover, it might have a positive effect on reducing cortisol during the latent phase. These findings might reassure women who are concerned about induction of labor.

Physiological and psychological stress responses to labor and delivery as expressed by salivary cortisol: a prospective study.

BACKGROUND: Labor is considered a stressful event, yet no study has described the course of stress measured by cortisol during labor and postpartum. OBJECTIVE: The objective of the study was to describe the patterns of physiological and psychological stress during labor as measured by salivary cortisol concentrations and stress questionnaires and their correlation to obstetric and neonatal outcomes. STUDY DESIGN: This prospective, observational study included 167 women with low-risk, singleton, term deliveries at a tertiary academic center. Physiological stress was evaluated by salivary cortisol measurements and emotional stress by questionnaire (stress scale ranging from 0 to 10) during the latent phase, active phase, and full dilation stages of labor as well as 2 minutes, 2 hours, and 24 hours after delivery. Cord blood cortisol and pH were also obtained. Modes of delivery, complications during labor and delivery, and early neonatal outcomes were evaluated. RESULTS: Salivary cortisol concentrations increased gradually from latent phase to active phase. The maximum increase was observed within 2 minutes of the delivery (from an average of 1.06 µg/dL to 1.67 µg/dL; 57% increase). Within 2 hours after delivery, cortisol decreased and reached a nongravid concentration after 24 hours (0.16 µg/dL). Cortisol concentrations during labor and up to 2 hours postpartum were above the average concentration of nongravid women (0.5 µg/dL). Women with epidural anesthesia had lower cortisol concentrations at complete dilation (P = .026) and 2 hours postpartum (P = .016) compared with women without epidural. Psychological stress peaked during latent and full dilation phases (mean 4.56 and 4.29, respectively). Maximum decrease from 4.29 to 2.04 (52%) occurred immediately postpartum. Cord cortisol was higher among women delivered by vacuum extraction compared with spontaneous vaginal delivery (17 ± 2 vs 11 ± 3.8, P = .03). CONCLUSION: This study reveals the course of cortisol concentrations during labor for low-risk pregnancies, with maximum increase immediately postpartum. Subjective stress levels decreased over the course of labor. Salivary cortisol portrays stress during labor and may be used as a reference to evaluate complicated pregnancies and to evaluate the role of cortisol during these deliveries.

Does stress affect IVF outcomes? A prospective study of physiological and psychological stress in women undergoing IVF.

RESEARCH QUESTION: What are the effects of physiological and psychological stress on fertility outcomes for women undergoing IVF? DESIGN: A prospective cohort study of 72 patients undergoing IVF in 2017 and 2018. Physiological stress was assessed by salivary cortisol measurements: (i) pretreatment, when the patient received the IVF protocol; (ii) before oocyte retrieval (follicular cortisol was also measured); and (iii) before embryo transfer. Emotional stress was evaluated at each assessment with the State-Trait Anxiety Inventory and a 1-10 Visual Analogue Scale (VAS, referred to as the 'Stress Scale'. Correlations between cortisol concentrations, psychological stress and IVF outcome were assessed. RESULTS: Salivary cortisol concentrations increased by 28% from pretreatment phase (0.46 ± 0.28 µg/dl) to maximum concentration on oocyte retrieval day (0.59 ± 0.29 µg/dl, P = 0.029) and then decreased by 29% on embryo transfer day (0.42 ± 0.23 µg/dl, P = 0.0162). On embryo transfer day, cortisol among women in their first cycle was higher than women who underwent more than one treatment (P = 0.024). Stress Scale score increased by 39% from pretreatment to a maximum score on oocyte retrieval day and then decreased by 12% on embryo transfer day. Salivary cortisol and Stress Scale were not related to subsequent embryo transfer, fertilization rate, embryo quality or clinical pregnancy rate. Follicular cortisol concentration was positively correlated with fertilization rate (r = 0.4, P = 0.004). CONCLUSION: It can be cautiously concluded that physiological and psychological stress do not negatively affect IVF outcomes. Moreover, high follicular cortisol concentrations might have positive effects on pregnancy rates.

Vitamin D diminishes the high platelet aggregation of type 2 diabetes mellitus patients.

Platelet activation is found in inflammatory conditions and implicated in the pathogenesis of chronic medical conditions, such as atherosclerosis, coronary vascular disease, cerebrovascular disease, and diabetes mellitus (DM). HbA1c is inversely related to vitamin D25 levels in individuals with and without DM. This study aimed to determine the relation between platelet aggregation, vitamin D and HbA1c among healthy individuals and those with Type 2 DM (T2DM). The direct effect of vitamin D1, 25 (calcitriol) on platelet aggregation was also investigated. The study included four groups: A. normoglycemic Control group: HbA1c<5.7%; B. Pre-diabetes (DM): 5.7% ≥ HbA1c ≤ 6.4%; C. DM on aspirin therapy: HbA1c>6.4%(+)Asp.; and D. DM not on aspirin therapy: HbA1c > 6.4%(-)Asp. Platelet aggregation was tested with and without calcitriol or saline pre-treatment, using collagen or adenosine diphosphate (ADP) as agonists. Platelet aggregation was higher in DM(-)Asp group compared to normoglycemic and DM(+)Asp, and higher, but not significant compared to pre-DM. The entire study population exhibited negative correlation between HbA1c and serum concentration of vitamin D25. Excluding DM(+)Asp, aggregation induced by collagen was significantly higher in patients with insufficient (<76 nmol/L) vitamin D25 compared to sufficient (≥76 nmol/L) vitamin D25. In this cohort, a negative correlation was found between serum concentrations of vitamin D25 and collagen-induced percent maximum (%max) aggregation and area under curve (AUC) aggregation. In the DM(-)Asp group, collagen-induced aggregation was reduced by approximately 25% after calcitriol treatment. Calcitriol decreased ADP-induced aggregation of control and DM(+)Asp groups to approximately 85% of saline treatment. We conclude that glycemic control is inversely associated with high platelet aggregation and low vitamin D25 levels. This elevated aggregation could be regulated by a novel, direct effect of calcitriol, indicating a beneficial effect of vitamin D on vascular complications related to diabetes. We offer a possible non-genomic mechanism for the vitamin D/Vitamin D receptor (VDR) pathway.

Ultra-Low Contrast Volume for Patients with Advanced Chronic Kidney Disease Undergoing Coronary Procedures.

BACKGROUND/AIMS: Contrast induced nephropathy (CIN) is associated with adverse clinical outcomes in patients undergoing coronary interventions, particularly in patients with advanced chronic kidney. The study was aimed to assess the real-life feasibility and safety of ultra-low volume coronary procedures in patients with advanced chronic kidney disease. METHODS: A prospective study that included patients with an estimated glomerular filtration rate (eGFR) <45 mL/min/1.73 m2) was conducted. Coronary procedures were performed using an ultra-low contrast volume technique. RESULTS: The 30 patients had a mean eGFR of 31.8(±8) mL/min/1.73 m2. Indications for coronary angiography were non-ST elevation myocardial infarction (63.3%), unstable (20%), and stable angina pectoris (16.7%). Median contrast volume for diagnostic coronary angiography was 13 mL (interquartile ranges [IQR] 12-14.9), and an additional 13 mL (IQR 8.8-14.3) for percutaneous coronary intervention (PCI). In 3 patients (10%), a ≥25% increase was demonstrated in serum cystatin C levels 48 h following the procedure. None of the patients demonstrated a ≥25% increase in serum creatinine levels at 48 h. Following 6 months, no patient required renal replacement therapy or unplanned coronary intervention. CONCLUSIONS: In patients with advanced chronic kidney disease, the ultra-low contrast technique is feasible and effective and can be used safely without a significant deterioration in renal function. This technique may increase the utilization of PCI in high-risk coronary patients with chronic kidney disease.

Chemical and thyroid hormone profile of the bone marrow interstitial fluid in hematologic disorders and patients without primary hematologic disorders.

Bone marrow interstitial fluid (BMIF) has not been well characterized. BMIF was isolated from 60 patients including plasma cell dyscrasias (PCD, n = 33), other primary hematologic disorders (OHD, n = 15), and patients with secondary or nonhemtologic disorders (NHD, n = 12) and analyzed for an array of chemical constituents. These included total cholesterol, glucose, phosphate, creatinine, urea, total protein, albumin, globulins, total bilirubin, aspartate aminotransferase, lactate dehydrogenase, sodium, osmolarity, free triiodothyronine (free T3), total triiodothyronine (total T3), and free tetraiodothyronine (free T4). Levels of BMIF components were compared between patient groups and to plasma levels. Compared with plasma, total cholesterol, total protein, total bilirubin, sodium, and calculated osmolarity were lower in BMIF in all groups (P < 0.05). Calculated globulins and aspartate aminotransferase were lower in BMIF of PCD patients and patients with NHD. Albumin was lower in BMIF of patients with PCD and patients with OHD. Lastly, free T4 was significantly higher in BMIF of patients with PCD and patients with OHD. Similar results were demonstrated in a separate analysis performed in patients with multiple myeloma. To conclude, the chemical and thyroid hormone composition of BMIF differs significantly from plasma in several key constituents.

[REPORTING CRITICAL LAB RESULTS, A CHALLENGE FOR THE LAB AND THE PHYSICIAN - A SUMMARY OF FOUR YEARS OF EXPERIENCE IN MEIR MEDICAL CENTER LABORATORIES].

INTRODUCTION: Critical laboratory results require prompt reporting to the attending physician, as they may indicate that a patient is in a life-threatening condition. Although this important subject has been covered in many publications, it needs more attention from our healthcare organizations, which have no official policy on the subject. Matching expectations between the doctor and the laboratory needs to be better defined. PURPOSE: The aim of this work was to inform the community of doctors and laboratories about the multiple problems concerning the reporting of critical laboratory results, to create a platform for exchanging views and ideas, and to build an extensive infrastructure for developing a unified plan to address this important issue. METHODS: We present the results of four years of experience of reporting critical laboratory values at the Meir Medical Center Laboratories. The idea leading this work was to present the relatively low rate of critical results reported by the laboratories in 2010, sharing the problems discovered while investigating the situation in depth, and presenting the solutions that enabled us to obtain the desired results within four years. RESULTS: Gradual implementation of these improvements resulted in critical value reporting increasing from 55% in 2010 to 95% currently. CONCLUSION: We suggest a model for improving critical laboratory values reporting based on our 4-year experience, which emphasizes: (1) The importance of selecting proper tests and values for critical results; (2) The significance of using technology and computerized measures to support the process; and (3) Developing quick procedures for monitoring and controlling the process.

Novel water-soluble bacteriochlorophyll derivatives for vascular-targeted photodynamic therapy: synthesis, solubility, phototoxicity and the effect of serum proteins.

New negatively charged water-soluble bacteriochlorophyll (Bchl) derivatives were developed in our laboratory for vascular-targeted photodynamic therapy (VTP). Here we focused on the synthesis, characterization and interaction of the new candidates with serum proteins and particularly on the effect of serum albumin on the photocytotoxicity of WST11, a representative compound of the new derivatives. Using several approaches, we found that aminolysis of the isocyclic ring with negatively charged residues markedly increases the hydrophilicity of the Bchl sensitizers, decreases their self-association constant and selectively increases their affinity to serum albumin, compared with other serum proteins. The photocytotoxicity of the new candidates in endothelial cell culture largely depends on the concentration of the serum albumin. Importantly, after incubation with physiological concentrations of serum albumin (500-600 microM), WST11 was found to be poorly photocytotoxic (>80% endothelial cell survival in cell cultures). However, in a recent publication (Mazor, O. et al. [2005] Photochem. Photobiol. 81, 342-351) we showed that VTP of M2R melanoma xenografts with a similar WST11 concentration resulted in approximately 100% tumor flattening and >70% cure rate. We therefore propose that the two studies collectively suggest that the antitumor activity of WST11 and probably of other similar candidates does not depend on direct photointoxication of individual endothelial cells but on the vascular tissue response to the VTP insult.

WST11, a novel water-soluble bacteriochlorophyll derivative; cellular uptake, pharmacokinetics, biodistribution and vascular-targeted photodynamic activity using melanoma tumors as a model.

WST11 is a novel negatively charged water-soluble palladium-bacteriochlorophyll derivative that was developed for vascular-targeted photodynamic therapy (VTP) in our laboratory. The in vitro results suggest that WST11 cellular uptake, clearance and phototoxicity are mediated by serum albumin trafficking. In vivo, WST11 was found to clear rapidly from the circulation (t1/2=1.65 min) after intravenous bolus injection in the mouse, whereas a longer clearance time (t1/2=7.5 min) was noted in rats after 20 min of infusion. The biodistribution of WST11 in mouse tissues indicates hepatic clearance (t1/2=20 min), with minor (kidney, lung and spleen) or no intermediary accumulation in other tissues. As soon as 1 h after injection, WST11 had nearly cleared from the body of the mouse, except for a temporal accumulation in the lungs from which it cleared within 40 min. On the basis of these results, we set the VTP protocol for a short illumination period (5 min), delivered immediately after WST11 injection. On subjecting M2R melanoma xenografts to WST11-VTP, we achieved 100% tumor flattening at all doses and a 70% cure with 9 mg/kg and a light exposure dose of 100 mW/cm2. These results provide direct evidence that WST11 is an effective agent for VTP and provide guidelines for further development of new candidates.

The expression of the chemokine receptor CXCR3 and its ligand, CXCL10, in human breast adenocarcinoma cell lines.

The acquisition of a metastatic phenotype in breast epithelial cells is a progressive process, influenced by a large variety of cellular and soluble factors. Of these, members of the chemokine superfamily, such as CCL2, CCL5, CXCL8 and CXCL12 have been recently suggested to promote breast cancer progression. A pre-requisite for elucidation of the role of other chemokines in breast cancer progression is the characterization of chemokine and chemokine receptor expression by breast tumor cells. The present study focuses on CXCL10, a CXC chemokine that was recently suggested to have anti-malignant properties, and its corresponding receptor CXCR3. CXCR3 expression was detected in three human breast adenocarcinoma cell lines, MDA-MB-231, MCF-7 and T47D. CXCR3 expression was potently up-regulated by growing the cells under stress conditions, imposed by serum starvation. Unlike many other chemokine receptors, CXCR3 expression was not down-regulated by exposure to high concentrations (500ng/ml) of its ligand, CXCL10, but rather was promoted. CXCL10-induced up-regulation of CXCR3 expression in the three cell lines was inhibited by cycloheximide, indicating that de novo protein synthesis is required for this process. In addition to CXCR3, the secretion of CXCL10 was noted in the MDA-MB-231, MCF-7 and T47D cells. CXCL10 secretion was found to be down-regulated by IL-6, a potentially pro-malignant cytokine in breast cancer. The concomitant expression of CXCR3 and CXCL10 in breast tumor cells suggests that a CXCR3-CXCL10 axis may function in these cells, and paves the way for an in depth analysis of CXCL10-CXCR3 interactions in breast tumor cells.

Progression of mouse mammary tumors: MCP-1-TNFalpha cross-regulatory pathway and clonal expression of promalignancy and antimalignancy factors.

The progression of breast cancer is affected by multiple cellular and microenvironmental components. The monocyte chemoattractant MCP-1, IL-6 and matrix metalloproteinases (MMP) were suggested to promote, each on its own, breast cancer progression. We recently demonstrated that the high-tumorigenicity phenotype of the DA3 and CSML murine mammary adenocarcinoma cells is correlated with a high expression of MCP-1, IL-6 and MMP. This raised the possibility that common intrinsic tumor-derived factors regulate the concordant expression of these 3 components. The aim of the present study was to gain insight into the mode by which the secretion of MCP-1, IL-6 and MMP from murine mammary adenocarcinoma cells is regulated. This was investigated in cellular clones established from a highly malignant variant of the DA3 tumor (DA3-high). We also determined the secretion of the antimalignancy chemokine IP-10 from these cells. The results indicate that the secretion levels of IL-6, MMP and IP-10 varied between the clones. In contrast, all the clones secreted uniformly high levels of MCP-1, suggesting that MCP-1 constitutes an important feature of the malignancy phenotype of mammary carcinoma. In most of the clones, elevated levels of 1 of the 3 promalignancy factors did not correlate with a high expression of the other 2 factors and vice versa. These findings indicate that the 3 promalignancy factors are not coregulated by a common intrinsic tumor-derived factor. Rather, these results suggest that the individual capacities of the different clones to secrete these factors are summed up in the high-malignancy DA3 parental tumor population, which secretes relatively high levels of MCP-1, IL-6 and MMP as compared to DA3 cells expressing a low-malignancy phenotype. In contrast to the lack of coordinated intrinsic regulation of MCP-1, IL-6 and MMP, it was found that recombinant TNFalpha, a product of tumor-associated macrophages contributing to breast cancer progression, upregulated the secretion of MCP-1, IL-6 and MMP from all the clones. These results suggest a key role for this microenvironmental, monocyte-derived cytokine in the coordinated regulation of these 3 molecules. Furthermore, additional results demonstrated that monocytic cell-derived TNFalpha upregulated MCP-1 secretion from the tumor cells and that MCP-1 in turn promoted the secretion of TNFalpha from monocytic cells. This may result in a positive feedback loop, whereby the tumor cells and the monocytic cells at tumor site promote each other's ability to express and secrete promalignancy factors. We next attempted to assess the contribution of the promalignancy factors MCP-1, IL-6 and MMP and of the antimalignancy factor IP-10 to mammary adenocarcinoma progression. To this end, a preliminary formula was developed in which the net balance between secretion levels of the promalignancy factors and that of the antimalignancy IP-10 chemokine from different clones was related to their in vivo tumorigenicity profile. This formula suggests that a balance between the secretion levels of these factors plays an important role in determining the malignancy phenotype of mammary carcinomas. In all, our findings demonstrate that the mammary tumor cell population is composed of a heterogeneous assortment of clones whose individual characteristics are averaged in the whole population. The malignancy potential of such tumors is thus determined, inter alia, by a combinatorial effect of several promalignancy and antimalignancy factors secreted from each of the clones comprising these tumors. Our results also suggest that the expression of such factors is determined by several nonmutually exclusive regulatory mechanisms.

Receptors involved in microenvironment-driven molecular evolution of cancer cells.

Cells, including cancer cells, communicate with their microenvironment via various types of membrane receptors. An important down-stream effect of such interactions is a change in the molecular phenotype of the cells. The microenvironment-driven molecular evolution of cancer cells may induce either growth arrest or death of the cells or alternatively, boost their malignancy phenotype. In this paper we summarize studies from our own laboratory on interactions of cancer cells with microenvironmental ligands via two types of receptors that are not commonly associated with tumour progression i.e. the receptor for the Fc portion of IgG, and Ly-6 proteins of mouse and human origin. We also review information on interactions of tumour-associated chemokines and chemokine receptors with the corresponding microenvironmental factors. We demonstrate how these interactions may drive the molecular evolution of tumour cells and discuss the possible impact of this evolution on tumour progression.

The CC chemokine RANTES in breast carcinoma progression: regulation of expression and potential mechanisms of promalignant activity.

Breast cancer progression may be affected by various cellular components expressed by the tumor cells and/or by microenvironmental factors. Many studies report the correlation between breast cancer progression and monocyte infiltration into the tumor site. We have identified recently the CC chemokine regulated on activation, normal T cell expressed and secreted (RANTES), a major monocyte chemoattractant expressed by breast tumor cells, as a potential contributor to breast cancer progression. In the present study, analysis of the regulation of RANTES expression demonstrates that the expression of RANTES in breast tumor cells is elevated significantly and in a synergistic manner by IFN-gamma and tumor necrosis factor-alpha. Identification of the mechanisms by which RANTES may contribute to breast cancer progression included the analysis of the potential ability of RANTES to act in paracrine and indirect mechanisms, as well as directly on the tumor cells, to promote disease progression. Our results suggest that breast tumor cell-derived RANTES may promote breast cancer progression by its partial contribution to monocyte migration into breast tumor sites. Moreover, RANTES promotes the expression of matrix metalloproteinase (MMP) 9 by THP-1 monocytic cells and elevates vascularity in chick chorioallantoic membrane assays. Tumor necrosis factor-alpha, a major monocyte-derived cytokine, was found to promote the expression of MMP9 and MMP2 by MCF-7 and T47D breast adenocarcinoma cells, respectively, and to induce the de novo expression of an additional proteolytic enzyme by T47D cells, presumably MMP9. The possibility that RANTES may act directly on breast tumor cells was supported by detection of the expression of the CCR5 RANTES receptor in biopsy sections of breast cancer patients and by the ability of RANTES to promote the expression of MMP9 by MCF-7 cells. In all, our study suggests that the expression of RANTES by breast tumor cells results not only in monocyte migration to the tumor site but also in protumorigenic activities of RANTES and of proinflammatory cytokines that may facilitate metastasis formation and contribute to disease progression.