Aging-associated changes in CD47 arrangement and interaction with thrombospondin-1 on red blood cells visualized by super-resolution imaging.

CD47 serves as a ligand for signaling regulatory protein α (SIRPα) and as a receptor for thrombospondin-1 (TSP-1). Although CD47, TSP-1, and SIRPα are thought to be involved in the clearance of aged red blood cells (RBCs), aging-associated changes in the expression and interaction of these molecules on RBCs have been elusive. Using direct stochastic optical reconstruction microscopy (dSTORM)-based imaging and quantitative analysis, we can report that CD47 molecules on young RBCs reside as nanoclusters with little binding to TSP-1, suggesting a minimal role for TSP-1/CD47 signaling in normal RBCs. On aged RBCs, CD47 molecules decreased in number but formed bigger and denser clusters, with increased ability to bind TSP-1. Exposure of aged RBCs to TSP-1 resulted in a further increase in the size of CD47 clusters via a lipid raft-dependent mechanism. Furthermore, CD47 cluster formation was dramatically inhibited on thbs1-/- mouse RBCs and associated with a significantly prolonged RBC lifespan. These results indicate that the strength of CD47 binding to its ligand TSP-1 is predominantly determined by the distribution pattern and not the amount of CD47 molecules on RBCs, and offer direct evidence for the role of TSP-1 in phagocytosis of aged RBCs. This study provides clear nanoscale pictures of aging-associated changes in CD47 distribution and TSP-1/CD47 interaction on the cell surface, and insights into the molecular basis for how these molecules coordinate to remove aged RBCs.

A close relationship between Helicobacter pylori infection and the serum level of CD47 in adults.

Objectives: Although Helicobacter pylori (H. pylori) infection is one of the most important risk factors for gastric cancer, the molecular mechanisms underlying the progression of H. pylori-induced gastric cancer remain unclear. Previous studies have demonstrated that Integrin-associated protein (CD47) plays an important role in the development of gastric cancer. Hence, the aim of this study was to preliminarily explore the relationship between CD47 and H. pylori infection.Methods: A total of 417 adults who underwent health checkups at a hospital were recruited in 2018. Serum levels of CD47 and tumor necrosis factor-α (TNF-α) were determined using an enzyme-linked immunosorbent assay. 13C urea breath test (13C-UBT) was carried out to diagnose H. pylori infection in all participants.Results: Compared with H. pylori-negative participants, H. pylori-positive participants have higher levels of serum CD47 and TNF-α. H. pylori infection, the levels of serum TNF-α and low density lipoprotein (LDL) are the independent predictors of serum level of CD47 in adults. In addition, a potential diagnostic value of serum CD47 level for H. pylori infection has been demonstrated in our study.Conclusion: H. pylori infection is closely associated with the serum level of CD47 in adults, suggesting that H. pylori may promote gastric cancer progression by activating CD47-mediated oncogenic pathways.

Extensive clinical, serologic and molecular studies lead to the first reported Rhmod phenotype in Argentina.

BACKGROUND: A highly reduced expression of Rh antigens in the erythrocyte membrane is the main feature of Rhmod , an extremely rare phenotype. Mutations within RHAG gene, which encodes RhAG glycoprotein and modulates Rh antigen expression and Rh complex formation, are the molecular events responsible for the Rhmod phenotype. Here we report a clinical, serologic, and molecular study of an Argentinean proband with Rh-deficiency syndrome. MATERIALS AND METHODS: Rh antigens, RhAG and CD47 glycoproteins were studied by serologic methods in the proband, her parents and sister. Osmotic fragility and viscoelastic parameters were also examined. RHD zygosity was analyzed by RFLP-PCR. RHD, RHCE, and RHAG genes were studied by Sanger sequencing. RESULTS: No Rh antigens were detected in the proband by standard techniques. However, adsorption-elution and anti-RhAG tests showed that the proposita was Rhmod . Reduced expression of CD47, enhanced osmotic fragility, and surface viscosity alterations giving rise to spherocytes were observed in the patient. Sequencing analysis showed that a c.920C>T mutation in RHAG Exon 6 was present in a homozygous state in the proband and in a heterozygous state in the rest of the family. This novel missense mutation caused the p.Ser307Phe amino acid substitution in Transmembrane Segment 10 of the RhAG glycoprotein. CONCLUSION: This comprehensive study determined the causes of the proband's anemia allowing the diagnosis of Rh-deficiency syndrome.

The expression of CD47 and its association with 2,3-DPG levels in stored leuco-reduced blood units.

BACKGROUND: Red blood cell (RBC) aging in transfusion medicine is characterized by alteration of many biochemical and morphological integrity of the cell referred to as red cell storage lesion (RCSL), CD47 is a protective marker expressed on RBCs that salvage the cell from phagocytosis. 2,3-diphosphoglycerate (2,3-DPG) tends to have a greater affinity towards deoxygenated hemoglobin. Any oxygen unloading at tissue capillaries are facilitated by 2,3-DPG, and any alterations in its levels can significantly interfere with oxygen release. Alteration of both CD47 expression and 2,3-DPG levels during red cell storage may serve as markers in the development of RCSL. The aim of this study was to validate the impact of storage time and leuco-depletion on CD47 expression on the RBCs, which could be a prospective marker for detection of RBCs viability and to clarify if the changes in CD47 expression and 2,3-DPG levels are correlated during storage of Packed RBCs. SUBJECTS AND METHODS: One hundred samples from Packed RBCs units were divided into two groups [Group 1 comprised unfiltered packed red cell units (n=50), whereas Group 2 included filtered "leuco-reduced" red cell units (n=50)]. Collection of samples was executed on days 0, 1 and 21. Each sample was measured for 2,3-DPG and alteration of CD47 expression on RBC using flow cytometry. RESULTS: Decreased CD47 expression along the storage period was statistically significant in both groups (P<0.05). Interestingly, the expression of CD47 was significantly higher in group 2 than group 1 on day zero, 1st and 21st days (P<0.05). Additionally, a statistically significant decrease in 2,3-DPG level was detected at day 21 of storage in group 1 compared to group 2 with a P-value of <0.001. There was a significant positive correlation (r=0.570, P<0.001) between CD47 MFI on RBC during storage and the level of 2,3-DPG at day 21 from packed RBCs storage. CONCLUSION: Older unfiltered RBC possesses lower expression of CD47 and low levels of 2,3-DPG, however filtration (leucoreduction) of RBCs units may help to retain considerable levels of 2,3-DPG and CD47 and hence sustains preservation of RBCs through reduction of phagocytosis.

Critical Features for Mesoporous Silica Nanoparticles Encapsulated into Erythrocytes.

Mesoporous silica nanoparticles (MSNs) hold great potential as a versatile platform for biomedical applications, especially drug delivery. However, evidence shows that MSNs even when PEGylated are rapidly cleared from the bloodstream by the monocyte phagocytic system. Erythrocytes, also called red blood cells (RBCs), can serve as biocompatible carriers of various bioactive substances, including drugs, enzymes, and peptides. In this work, we synthesize a series of fluorescent PEGylated MSNs with different synthetic diameters ranging from 10 to 200 nm and investigate the size effect on their encapsulation in human RBCs (hRBCs) by a hypotonic dialysis-based method. According to fluorescence images and flow cytometry analyses, we demonstrated that a hydrodynamic diameter below 30 nm is critical for efficient MSN encapsulation. Confocal microscopy and scanning electron microscopy images further confirmed that PEGylated MSNs were successfully embedded inside RBC. PEGylation serves an important role not only for stabilizing MSNs in biological milieu but also for reducing significant hemolysis caused by bare MSNs and thus for successful encapsulation. In addition to PEGylation, we further introduce positively charged functional groups onto the MSNs to show that nanoparticle-encapsulated hRBCs could serve as depots for delivering biological molecules through electrostatic attraction or chemical conjugation with MSNs. Also, we verify the existence of CD47 membrane protein, a marker of self, on the nanoparticle-encapsulated hRBCs and assess its ability of circulation in the blood, which could act as a circulation reservoir for delivering pharmacological substances through an osmosis-based method with MSNs.

CD47 overexpression is associated with decreased neutrophil apoptosis/phagocytosis and poor prognosis in non-small-cell lung cancer patients.

BACKGROUND: Non-small-cell lung cancer (NSCLC) patients often exhibit neutrophilia, which has been associated with poor clinical outcomes. However, the mechanisms that lead to neutrophilia have not been fully established. CD47 is an antiphagocytic molecule that promotes neutrophil recruitment. METHODS: Blood was collected from 50 treatment-naive patients with advanced NSCLC and from 25 healthy subjects. The frequency of CD66b+ cells and the expression of CD47 were determined by flow cytometry. Neutrophil apoptosis was determined by 7-amino-actinomycin D/Annexin V-APC staining. Phagocytosis was assessed by flow cytometry. Reactive oxygen species production after phorbol 12-myristate 13-acetate treatment was quantified by 2',7'-dichlorofluorescein fluorescence. Pro-inflammatory plasma cytokines were quantified using a cytometric bead array assay. RESULTS: The percentage of circulating neutrophils was significantly higher in patients than in controls (P<0.001). Patient-derived neutrophils had a higher oxidative potential than those of controls (P=0.0286). The number of neutrophils in late apoptosis/necrosis was lower in patients than in controls (P=0.0317). Caspase 3/7 activation was also lower in patients than in controls (P=0.0079). CD47 expression in whole-blood samples and in the neutrophil fraction was higher in NSCLC patients than in controls (P=0.0408 and P<0.001). Patient-derived neutrophils were phagocytosed at a lower rate than those of controls (P=0.0445). CD47 expression in neutrophils negatively correlated with their ingestion by macrophages (P=0.0039). High CD47 expression was associated with a lower overall survival. CONCLUSIONS: Increased CD47 expression on the surface of neutrophils was associated with a delay in neutrophil apoptosis and with an impairment in their phagocytic clearance by macrophages, suggesting that CD47 overexpression may be one of the underlying mechanisms leading to neutrophilia in NSCLC patients.

Pathophysiological aspects of red blood cells in end-stage renal disease patients resistant to recombinant human erythropoietin therapy.

OBJECTIVE: Modified, bioreactive red blood cells (RBCs) and RBC-derived microvesicles (MVs) likely contribute to the hematological and cardiovascular complications in end-stage renal disease (ESRD). This study assesses the physiological profile of RBCs in patients with ESRD receiving standard or high doses of recombinant human erythropoietin (rhEPO). METHOD: Blood samples from twenty-eight patients under sustained hemodialysis, responsive, or not to standard rhEPO administration were examined for RBC morphology, fragility, hemolysis, redox status, removal signaling, membrane protein composition, and microvesiculation before and after dialysis. Acute effects of uremic plasma on RBC features were examined in vitro through reconstitution experiments. RESULTS: Overall, the ESRD RBCs were characterized by pathological levels of shape distortions, surface removal signaling, and membrane exovesiculation, but reduced fragility compared to healthy RBCs. Irreversible transformation of RBCs was found to be a function of baseline Hb concentration. The more toxic uremic context in non-responsive patients compared to rhEPO responders was blunted in part by the antioxidant, antihemolytic, and anti-apoptotic effects of high rhEPO doses, and probably, of serum uric acid. A selective lower expression of RBC membrane in complement regulators (CD59, clusterin) and of CD47 "marker-of-self" was detected in non-responders and responders, respectively. Evidence for different short-term dialysis effects and probably for a different erythrocyte vesiculation mechanism in rhEPO responsive compared to non-responsive patients was also revealed. CONCLUSION: Deregulation of RBC homeostasis might involve diverse molecular pathways driving erythrocyte signaling and removal in rhEPO non-responders compared to responsive patients.

The effects of obesity on CD47 expression in erythrocytes.

BACKGROUND: To investigate the effects of obesity on CD47, phosphatidylserine (PS) exposure, and Caspase-8 and Caspase-3 activities in erythrocytes. METHODS: The study included 25 morbidly obese patients and 20 healthy people as the control group. We evaluated CD47 expression on the red blood cell (RBC) membrane surface and eryptosis markers such as PS externalization and caspase activity using flow cytometric analyses. RESULTS: CD47 expression on the RBC surface was significantly lower in obese patients than in the control group (P = 0.000001). We did not find significant differences in the Caspase-3 and Caspase-8 activities between the obese and nonobese control groups. Additionally, we did not find differences in PS exposure on erythrocyte membranes. The fibrinogen levels were higher in the obese group than they were in the control group (P = 0.00002). Correlations between CD47 expression and body mass index (r = -0.65; P = 0.0004), waist circumference (r = -0.54; P = 0.0052), and fibrinogen (r = 0.57; P = 0.0024) were found. Univariate analyses revealed that body mass index, waist circumference, hip circumference, and fibrinogen levels were potential predictors of CD47 expression. Multivariate analyses found that fibrinogen levels (ß = 0.4708; P = 0.045) independently predicted CD47 expression. CONCLUSIONS: The study demonstrated that CD47 expression is decreased on the surface of RBCs in obese subjects. These changes in CD47 expression on the RBC surface may be an adaptive response to hyperfibrinogenemia associated with obesity. © 2015 International Clinical Cytometry Society.

Loss of CD47 Makes Dendritic Cells See Red.

Whereas dendritic cells (DCs) can be activated in many ways to trigger immunity, hardly anything is known about the mechanisms that counterbalance DC activation. Cyster and colleagues now demonstrate that the "self" molecule CD47 on erythrocytes critically restricts splenic DC activation.

Splenic Dendritic Cells Survey Red Blood Cells for Missing Self-CD47 to Trigger Adaptive Immune Responses.

Sheep red blood cells (SRBCs) have long been used as a model antigen for eliciting systemic immune responses, yet the basis for their adjuvant activity has been unknown. Here, we show that SRBCs failed to engage the inhibitory mouse SIRPα receptor on splenic CD4(+) dendritic cells (DCs), and this failure led to DC activation. Removal of the SIRPα ligand, CD47, from self-RBCs was sufficient to convert them into an adjuvant for adaptive immune responses. DC capture of Cd47(-/-) RBCs and DC activation occurred within minutes in a Src-family-kinase- and CD18-integrin-dependent manner. These findings provide an explanation for the adjuvant mechanism of SRBCs and reveal that splenic DCs survey blood cells for missing self-CD47, a process that might contribute to detecting and mounting immune responses against pathogen-infected RBCs.

Storage of red blood cells affects membrane composition, microvesiculation, and in vitro quality.

BACKGROUND: During storage detrimental biochemical and biomechanical changes occur within a red blood cell (RBC). RBC microparticles (RMPs) produced during storage have been identified as biomarkers of RBC quality, being potentially immunogenic and inhibitory to nitric oxide regulation. STUDY DESIGN AND METHODS: In this study, microvesiculation and changes in the composition of the RBC membrane were investigated throughout 49 days of storage and were correlated with in vitro assays examining membrane quality. Leukoreduced RBC units produced using the buffy coat method were collected and stored at 1 to 6°C and were tested weekly for hemolysis, osmotic fragility, deformability, ATP, hematologic indices, and morphology. Microvesiculation was assessed using multicolor flow cytometry. High-performance liquid chromatography and mass spectrometry were used to determine the composition and quantity of phospholipids (PLs) and cholesterol (C) on Days 2 and 43. RESULTS: The assessment of RBCs throughout storage revealed significant increases in percent hemolysis, while significant decreases in ATP concentrations, and the mean corpuscular hemoglobin concentration were observed. Flow cytometry analysis revealed a significant increase in the mean number of microparticles per microliter during storage. Throughout storage, significant decreases were identified in the amount of PLs and total lipids within the RBC membrane. No significant change in the amount of C in the RBC membrane was identified. CONCLUSION: Significant changes to the RBC membrane occur during storage. The length of storage will influence RMP generation, osmotic fragility, hemolysis, and changes in deformability. These changes in RBC in vitro quality may contribute to transfusion reactions and negative posttransfusion outcomes.

Fibrinogen interaction with the red blood cell membrane.

A brief review of the fibrinogen molecule composition and structure is presented like as an introduction to the effects of this plasma protein on the red blood cell hemorheoplogical properties namely erythrocyte aggregation tendency and deformability ability. The protein membrane RBC target for fibrinogen is also highlight as well as the erythrocyte signal transduction pathway associated with nitric oxide mobilization resulting from its binding.

Study of the D-- phenotype reveals erythrocyte membrane alterations in the absence of RHCE.

Red cells with the D-- phenotype do not express the RHCE protein because of mutations in both alleles of the RHCE gene. At present, little is known of the effect this has on the normal function of erythrocytes. In this study a group of five families belonging to a nomadic tribe in Malaysia were identified as carriers of the D-- haplotype. Analysis of homozygous individuals' genomic DNA showed two separate novel mutations. In four of the families, RHCE exons 1, 9 and 10 were present, while the 5th family possessed RHCE exons 1-3 and 10. Analysis of cDNA revealed hybrid transcripts, suggesting a gene conversion event with RHD, consistent with previously reported D-- mutations. Immunoblotting analysis of D-- erythrocyte membrane proteins found that Rh-associated glycoprotein (RHAG) migrates with altered electrophoretic mobility on sodium dodecyl sulphate polyacrylamide gel electrophoresis, consistent with increased glycosylation. Total amounts of Rh polypeptide in D-- membranes were comparable with controls, indicating that the exalted D antigen displayed by D-- red cells may be associated with altered surface epitope presentation. The adhesion molecules CD44 and CD47 are significantly reduced in D--. Together these results suggest that absence of RHCE polypeptide alters the structure and packing of the band 3/Rh macrocomplex.

Lack of evidence for increased level of circulating urothelial cells in the peripheral blood after transurethral resection of bladder tumors.

PURPOSE: Aggressive intervention against the bladder wall during transurethral resection of bladder tumors (TURBT) causes damage and leakage from blood vessels to the bladder lumen. The aim of this study was to determine whether TURBT could increase the level of circulating urothelial cells. METHODS: Expression of tumor markers, discriminative for nucleated blood cells and urothelium, was evaluated by quantitative (q) RT-PCR on RNA isolated from peripheral blood samples of 51 patients who underwent TURBT for ≥cT1c bladder tumors. RESULTS: Four of 14 studied genes, epidermal growth factor receptor (EGFR), Collagen α-1(I) chain, Mast/stem cell growth factor receptor (KIT) and CD47, exhibited significant differences in gene expression between controls and cancer patients. While TURBT did not significantly increase the number of PCR-positive results of any transcripts, positive RT-PCR detection for EGFR was significantly less frequent on day 30 compared to results obtained before surgery. CONCLUSIONS: Although the results of our study do not provide evidence for increased tumor cell release into the peripheral blood after TURBT, they seem to indicate that EGFR mRNA measurement in the blood may provide useful information for urologists.

Cofactor regulation of C5a chemotactic activity in physiological fluids. Requirement for the vitamin D binding protein, thrombospondin-1 and its receptors.

Factors in physiological fluids that regulate the chemotactic activity of complement activation peptides C5a and C5a des Arg are not well understood. The vitamin D binding protein (DBP) has been shown to significantly enhance chemotaxis to C5a/C5a des Arg. More recently, platelet-derived thrombospondin-1 (TSP-1) has been shown to facilitate the augmentation of C5a-induced chemotaxis by DBP. The objective of this study was to better characterize these chemotactic cofactors and investigate the role that cell surface TSP-1 receptors CD36 and CD47 may play in this process. The chemotactic activity in C-activated normal serum, citrated plasma, DBP-depleted serum or C5 depleted serum was determined for both normal human neutrophils and U937 cell line transfected with the C5a receptor (U937-C5aR). In addition, levels of C5a des Arg, DBP and TSP-1 in these fluids were measured by RIA or ELISA. Results show that there is a clear hierarchy with C5a being the essential primary signal (DBP or TSP-1 will not function in the absence of C5a), DBP the necessary cofactor and TSP-1 a dependent tertiary factor, since it cannot function to enhance chemotaxis to C5a without DBP. Measurement of the C5a-induced intracellular calcium flux confirmed the same hierarchy observed with chemotaxis. Moreover, analysis of bronchoalveolar lavage fluid (BALF) from patients with the adult respiratory distress syndrome (ARDS) demonstrated that C5a-dependent chemotactic activity is significantly decreased after anti-DBP treatment. Finally, results show that TSP-1 utilizes cell surface receptors CD36 and CD47 to augment chemotaxis, but DBP does not bind to TSP-1, CD36 or CD47. The results clearly demonstrate that C5a/C5a des Arg needs both DBP and TSP-1 for maximal chemotactic activity and suggest that the regulation of C5a chemotactic activity in physiological fluids is more complex than previously thought.

A cytometric study of the red blood cells in Gaucher disease reveals their abnormal shape that may be involved in increased erythrophagocytosis.

BACKGROUND: Gaucher disease is a sphingolipidosis caused by a deficiency of the enzyme glucocerebrosidase. Macrophages transform into pathogenic Gaucher cells following the phagocytosis of red blood cells (RBCs) and subsequent accumulation of glucosylceramide. Enhanced erythrophagocytosis is one feature of the disease indicating abnormal macrophage-RBC interactions. We hypothesized that the erythrophagocytosis observed in Gaucher disease may be at least partly due to abnormalities in the RBCs themselves. METHODS: To investigate this hypothesis, we used flow cytometry FSC/SSC to study RBCs sampled from seven patients with Gaucher disease in terms of their shape and the expression of markers of senescence and phagocytosis. Cells from two of the seven patients were evaluated before and 9 months after the start of enzyme-replacement therapy. RESULTS: Untreated patients were found to have abnormal flow-cytometry profiles suggesting an alteration of Gaucher RBC morphology. Scanning electron microscopy confirmed this finding by revealing many abnormally shaped RBCs. Whereas there was no evidence of desialylation of membrane glycoconjugates or phosphatidylserine exposure, RBC viability (calcein-AM test) and CD47 expression were reduced. These anomalies found in RBCs sampled from two patients before treatment, were no longer present after a 9 month-long enzyme-replacement therapy. CONCLUSIONS: We report on previously overlooked alterations of Gaucher RBCs that may facilitate erythrophagocytosis in untreated patients. Their potential role in the anemia, the excess of aggregation and rheological anomalies associated with Gaucher disease must now be addressed. RBC anomalies may take part in the abnormal crosstalk between RBCs and macrophages leading to the accumulation of Gaucher cells.

T-cell expression of CD91 - a marker of unresponsiveness to anti-TNF therapy in rheumatoid arthritis.

The aim of this study was to investigate the expression of thrombospondin-1 (TSP-1) and its receptors, lipoprotein receptor-related protein/cluster of differentiation (CD)91, calreticulin (CRT), and CD47, on T cells and monocytes from patients with rheumatoid arthritis (RA) treated with anti-tumor necrosis factor (TNF) therapy. The surface expression of CD91 and associated components on CD3- and CD14-positive cells was examined using flow cytometry in 12 patients with established RA before and after beginning therapy and compared with that of 9 healthy controls and 12 patients with early RA treated with conventional therapies. CD3-positive cells from anti-TNF non-responders showed significantly greater expression of CD91 expression than those from responders (p<0.05) after 6 weeks and when all measurements were pooled (p<0.001). CD91 expression on CD3-positive cells from non-responders to other therapies was at the same level as in healthy controls. In contrast, CD14-positive cells showed no differences in CD91 expression between patients and controls or between responders and non-responders to anti-TNF therapy. The expression of TSP-1, CRT, and CD47 showed no differences between responders and non-responders. The results suggest T-lymphocyte expression of CD91 to be a biomarker that signifies unresponsiveness to anti-TNF therapy in patients with RA and may be used to identify potential responders and non-responders.

Correlated expression of CD47 and SIRPA in bone marrow and in peripheral blood predicts recurrence in breast cancer patients.

PURPOSE: CD47 plays a variety of roles in intercellular signaling. Herein, we focused on the clinicopathologic significance of CD47 expression in human breast cancer. Our data suggest that the correlation between CD47 and signal regulatory protein α (SIRPA) expression may play a key role in the progression of breast cancer. EXPERIMENTAL DESIGN: Quantitative real-time PCR was used to evaluate CD47 mRNA and SIRPA mRNA expression in bone marrow and in peripheral blood from 738 cases of breast cancer. RESULTS: In patients with high levels of CD47 expression in the bone marrow, survival was significantly poorer compared with patients with low levels of CD47 expression [disease-free survival (DFS), P = 0.0035; overall survival (OS), P = 0.015]. Furthermore, high CD47 expression group in a multivariate analysis showed significance as an independent variable for poorer prognosis in DFS (P = 0.024). In the peripheral blood, however, high CD47 expression in patients was not an independent and significant prognostic factor for DFS and OS in a multivariate analysis. CD47 expression was strongly correlated with SIRPA expression in both the bone marrow (P < 0.0001) and peripheral blood (P < 0.0001) of breast cancer patients. CONCLUSIONS: This is one of the first studies to show that a host factor in bone marrow confers prognostic importance. CD47 is an important biomarker in breast cancer, and functions as a prognostic factor for DFS. Moreover, we suggest that the poor prognosis of breast cancer patients with high expression of CD47 is due to an active CD47/SIRPA signaling pathway in circulating cells.

[Integrin-associated proteins in blood plasma of patients with acute exacerbation of chronic obstructive pulmonary disease].

OBJECTIVE: To explore the role of CD(47) and P-selectin in patients with COPD. METHODS: The blood plasma levels of CD(47) and P-selectin in 20 healthy volunteers (control group) and 35 patients with COPD in acute exacerbation and at stable stage were measured by flow cytometry. Platelet count was measured by hematology analyzer. SNK-q test and Pearson correlation analysis of the regression equation were used for statistics. RESULTS: The level of CD(47) in the COPD acute exacerbation group [(93 +/- 4)%] was significantly higher than that of the COPD stable group [(72 +/- 11)%] and that of the control group [(67 +/- 10)%], q = 11.26, 13.32, all P < 0.01, but the difference in CD(47) between the stable group and the control group was not significant (q = 1.73, P > 0.05). The level of P-selectin in the acute exacerbation group [(35 +/- 11)%] was significantly higher than those of the stable group [(12 +/- 8)%] and the control group [(10 +/- 4)%] (q = 9.93, 12.19, all P < 0.05), and the level of stable group was also higher than that of the control group (q = 1.90, P < 0.05). The difference in platelet counts among the acute exacerbation group [(188 +/- 56) x 10(9)/L], the stable group [(213 +/- 57) x 10(9)/L] and the control group [(204 +/- 51) x 10(9)/L] was not significant (F = 1.74, P > 0.05). A significant positive correlation between CD(47) and P-selectin was observed in the acute exacerbation group(r = 0.77, P < 0.01), but not in the stable group and the control group (r = -0.04, -0.15, all P > 0.05). CONCLUSIONS: The levels of CD(47) and P-selectin as markers of platelet activation increase significantly during AECOPD, which suggests that platelet activation exists in AECOPD and platelets as a type of inflammatory cells participate in the disease.