Beyond the Role of CD55 as a Complement Component

The complement is a part of the immune system that plays several roles in removing pathogens. Despite the importance of the complement system, the exact role of each component has been overlooked because the complement system was thought to be a nonspecific humoral immune mechanism that worked against pathogens. Decay-accelerating factor (DAF or CD55) is a known inhibitor of the complement system and has recently attracted substantial attention due to its role in various diseases, such as cancer, protein-losing enteropathy, and malaria. Some protein-losing enteropathy cases are caused by CD55 deficiency, which leads to complement hyperactivation, malabsorption, and angiopathic thrombosis. In addition, CD55 has been reported to be an essential host receptor for infection by the malaria parasite. Moreover, CD55 is a ligand of the seven-span transmembrane receptor CD97. Since CD55 is present in various cells, the functional role of CD55 has been expanded by showing that CD55 is associated with a variety of diseases, including cancer, malaria, protein-losing enteropathy, paroxysmal nocturnal hemoglobinuria, and autoimmune diseases. This review summarizes the current understanding of CD55 and the role of CD55 in these diseases. It also provides insight into the development of novel drugs for the diagnosis and treatment of diseases associated with CD55.

Production of α1,3-galactosyltransferase targeted pigs using transcription activator-like effector nuclease-mediated genome editing technology

Recent developments in genome editing technology using meganucleases demonstrate an efficient method of producing gene edited pigs. In this study, we examined the effectiveness of the transcription activator-like effector nuclease (TALEN) system in generating specific mutations on the pig genome. Specific TALEN was designed to induce a double-strand break on exon 9 of the porcine α1,3-galactosyltransferase (GGTA1) gene as it is the main cause of hyperacute rejection after xenotransplantation. Human decay-accelerating factor (hDAF) gene, which can produce a complement inhibitor to protect cells from complement attack after xenotransplantation, was also integrated into the genome simultaneously. Plasmids coding for the TALEN pair and hDAF gene were transfected into porcine cells by electroporation to disrupt the porcine GGTA1 gene and express hDAF. The transfected cells were then sorted using a biotin-labeled IB4 lectin attached to magnetic beads to obtain GGTA1 deficient cells. As a result, we established GGTA1 knockout (KO) cell lines with biallelic modification (35.0%) and GGTA1 KO cell lines expressing hDAF (13.0%). When these cells were used for somatic cell nuclear transfer, we successfully obtained live GGTA1 KO pigs expressing hDAF. Our results demonstrate that TALEN-mediated genome editing is efficient and can be successfully used to generate gene edited pigs.

A Novel Marker for Screening Paroxysmal Nocturnal Hemoglobinuria Using Routine Complete Blood Count and Cell Population Data

BACKGROUND: Final diagnosis of paroxysmal nocturnal hemoglobinuria (PNH) may take years demanding a quick diagnosis measure. We used the facts that PNH cells are damaged in acid, and reagents for measuring reticulocytes in Coulter DxH800 (Beckman Coulter, USA) are weakly acidic and hypotonic, to create a new PNH screening marker. METHODS: We analyzed 979 complete blood counts (CBC) data from 963 patients including 57 data from 44 PNH patients. Standard criteria for PNH assay for population selection were followed: flow cytometry for CD55 and CD59 on red blood cells (RBCs) to a detection level of 1%; and fluorescent aerolysin, CD24 and CD15 in granulocytes to 0.1%. Twenty-four PNH minor clone-positive samples (minor-PNH+) were taken, in which the clone population was <5% of RBCs and/or granulocytes. Excluding PNH and minor-PNH+ patients, the population was divided into anemia, malignancy, infection, and normal groups. Parameters exhibiting a distinct demarcation between PNH and non-PNH groups were identified, and each parameter cutoff value was sought that includes the maximum [minimum] number of PNH [non-PNH] patients. RESULTS: Cutoff values for 5 selected CBC parameters (MRV, RDWR, MSCV, MN-AL2-NRET, and IRF) were determined. Positive rates were: PNH (86.0%), minor-PNH+ (33.3%), others (5.0%), anemia (13.4%), malignancy (5.3%), infection (3.7%), normal (0.0%); within anemia group, aplastic anemia (40.0%), immune hemolytic anemia (11.1%), iron deficiency anemia (1.6%). Sensitivity (86.0%), specificity (95.0%), PPV (52.1%), and NPV (99.1%) were achieved in PNH screening. CONCLUSION: A new PNH screening marker is proposed with 95% specificity and 86% sensitivity. The flag identifies PNH patients, reducing time to final diagnosis by flow cytometry.

Expression of CD55 and CD59 in chronic rhinosinusitis and its significance / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To understand the expression of complement regulatory proteins CD55 and CD59, which secreted by epithelial cells of normal and chronic sinusitis patients.</p><p><b>METHODS</b>Cell culture and flow cytometry were used to detect the expression of complement regulatory proteins CD55 and CD59.SPSS 18.0 software was used to analyze the data.</p><p><b>RESULTS</b>CD55 was expressed both in normal nasal mucosa and mucosa of chronic sinusitis. The expression in normal group was 0.001 ± 0.001, significantly lower than that in CRS group which was 0.067 ± 0.028 (t = -10.535, P < 0.01). CD59 was also expressed in the two groups . In normal group, the expression of CD59 was 0.879 ± 0.005, significantly higher than that in CRS group which was 0.238 ± 0.034 (t = 83.416, P < 0.01).</p><p><b>CONCLUSIONS</b>The nasal mucosa in CRS patients showed low expression of CD55 and high expression of CD59. This mechanism may be involved in the occurrence of CRS.</p>

Detection of paroxysmal nocturnal hemoglobinuria-phenotype in patients with chronic lymphocytic leukemia and multiple myeloma.

Background : Paroxysmal nocturnal hemoglobinuria (PNH) results due to decrease or absence of glycosylphosphatidylinositol-anchored (GPI) molecules, such as CD55 and CD59, from the surface of the affected cells. PNH-phenotype has been described in various hematological disorders, mainly aplastic anemia and myelodysplastic syndromes; recently it has been reported in patients with lymphoproliferative syndromes and multiple myeloma (MM). Materials and Methods : We evaluated the presence of CD55 negative and/or CD59 negative red blood cell (RBC) populations in newly diagnosed treatment naive-54 chronic lymphocytic leukemia (CLL) and 29 MM patients by flow cytometry. Results : PNH-phenotype was not reported in any patient; however, RBC populations deficient in CD55 were detected in 16.66% (9/54) CLL and 6.89% (2/29) MM patients. Clinical presentation or the hematological parameters did not show any relationship with the presence of CD55 deficient RBC population. Conclusion : Our study showed absence of PNH-phenotype in patients with CLL and MM; however, isolated CD55 deficient RBC were identified in both CLL and MM. Larger prospective studies by other centers, including simultaneous analysis of granulocytes for the presence of PNH-phenotype, are needed to corroborate these findings and to work out the mechanisms and the significance of the existence of this phenotype in these patients.

Anaemia & expression levels of CD35, CD55 & CD59 on red blood cells in Plasmodium falciparum malaria patients from India.

Background & objectives: Severe anaemia in Plasmodium falciparum (Pf) associated malaria is a leading cause of death despite low levels of parasitaemia. In an effort to understand the pathogenesis of anaemia we studied expression level of RBC complement regulatory proteins, CR1 (CD35), CD55 and CD59 with haemoglobin status in a group of malaria cases from Assam, Goa and Chennai, and in healthy controls. Methods: Flowcytometry was used to study expression of CR1, CD55 and CD59 in 50 Pf cases and 30 normal healthy volunteers. Giemsa stained thick and thin blood films were used for microscopic detection and identification of malarial parasites and parasite count. Results: No correlation was found between degree of expression of RBC surface receptors CR1, CD55 and CD59 with haemoglobin level. However, expression of CD55 was less in malaria cases than in healthy controls. Interpretation & conclusions: The present findings indicate that malaria infection changes the expression profile of complement regulatory protein CD55 irrespective of severity status of anaemia. Further studies are needed to explore the pathophysiology of anaemia in malaria cases in Assam where expression of RBC complement receptors appears to be low even in normal healthy population.

Frequency of paroxysmal nocturnal hemoglobinuria in patients attended in Belém, Pará, Brazil

BACKGROUND: Paroxysmal nocturnal hemoglobinuria is a hematological disease with complex physiopathology. It is genetically characterized by a somatic mutation in the PIG-A gene (phosphatidylinositol glycan anchor biosynthesis, class A), in which the best known antigens are DAF (decay accelerating factor or CD55) and MIRL (membrane inhibitor of reactive lysis or CD59). OBJECTIVE: To determine the frequency of paroxysmal nocturnal hemoglobinuria in patients attended at the HEMOPA foundation from November 2008 to July 2009. METHOD: Thirty patients, with ages ranging from two to 79 years old and suspected of having paroxysmal nocturnal hemoglobinuria were examined. All patients were immunophenotyped by flow cytometry for the CD5, CD59, CD16 and CD45 antigens. RESULTS: Paroxysmal nocturnal hemoglobinuria was identified in nine of the thirty patients investigated. Another 3 cases had inconclusive results with CD59-negative labeling only for neutrophils. The highest frequency of paroxysmal nocturnal hemoglobinuria patients (7/9) and inconclusive cases (2/3) were between 19 years old and 48 years old, with a median of 28 years. CONCLUSION: These results show the importance of flow cytometry to identify cases in which patients are deficient in only one antigen (CD59).

The Stromal Overexpression of Decay Accelerating Factor (DAF/CD55) Correlates with Poor Clinical Outcome in Colorectal Cancer Patients

BACKGROUND: Decay accelerating factor (DAF/CD55), regulates the complement system by accelerating decay of the C3 convertase, has been described in several malignancies, however, the clinicopathologic significance of CD55 and its receptor CD97 has not been fully investigated. We examined the expression patterns of both CD55 and CD97 and their association with clinicopathologic parameters in colorectal cancers (CRCs). METHODS: Expression patterns of CD55 and CD97 in the stroma and tumor cells at tumor center and invasive front were examined in 130 CRCs, and their significance was statistically evaluated. RESULTS: CD55-high stroma was correlated with tumor border (p=0.006) and invasion depth (p=0.013). CD55-high tumor cells at tumor center and invasive front were correlated with histologic grade, and CD55-high tumor cells at invasive front with tumor, node and metastasis (TNM) stage (p<0.05). CD97-high stroma was correlated with lymph node metastasis (p=0.016) and TNM stage (p=0.030). CD97-high tumor cells at tumor center and invasive front were correlated with tumor size and CD97-high tumor cells at tumor center with tumor border (p<0.05). Patients with CD55-high stroma showed poor overall and recurrence-free survival (p<0.05) in univariate analysis, and were independently associated with short recurrence-free survival (p=0.025) in multivariate analysis. CONCLUSIONS: Stromal CD55 overexpression would be an indicator of adverse clinical outcome and a useful prognostic factor.

PNH revisited: Clinical profile, laboratory diagnosis and follow-up.

BACKGROUND: Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by intravascular hemolysis, marrow failure, nocturnal hemoglobinuria and thrombophila. This acquired disease caused by a deficiency of glycosylphosphatidylinositol (GPI) anchored proteins on the hematopoietic cells is uncommon in the Indian population. MATERIALS AND METHODS: Data of patients diagnosed with PNH in the past 1 year were collected. Clinical data (age, gender, various presenting symptoms), treatment information and follow-up data were collected from medical records. Results of relevant diagnostic tests were documented i.e., urine analysis, Ham's test, sucrose lysis test and sephacryl gel card test (GCT) for CD55 and CD59. RESULTS: A total of 5 patients were diagnosed with PNH in the past 1 year. Presenting symptoms were hemolytic anemia (n=4) and bone marrow failure (n=1). A GCT detected CD59 deficiency in all erythrocytes in 4 patients and CD55 deficiency in 2 patients. A weak positive PNH test for CD59 was seen in 1 patient and a weak positive PNH test for CD55 was seen in 3 patients. All patients were negative by sucrose lysis test. Ham's test was positive in two cases. Patients were treated with prednisolone and/or androgen and 1 patient with aplastic anemia was also given antithymocyte globulin. A total of 4 patients responded with a partial recovery of hematopoiesis and 1 patient showed no recovery. None of the patients received a bone marrow transplant. CONCLUSION: The study highlights the diagnostic methods and treatment protocols undertaken to evaluate the PNH clone in a developing country where advanced methods like flowcytometry immunophenotyping (FCMI) and bone marrow transplants are not routinely available.

Decreased expression of complement regulatory proteins, CD55 and CD59, on peripheral blood leucocytes in patients with type 2 diabetes and macrovascular diseases / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Macro- and microvascular diseases are the leading cause of morbidity and mortality in diabetic patients, but their mechanisms remain unclear. Recent reports provide evidence that the levels of CD55 and CD59 are decreased in diabetic microvascular diseases. However, very little is known about the levels of CD55 and CD59, the relationship between them and carotid artery intima-media thickness, and the effects of statins on CD55 and CD59 in diabetic macrovascular diseases.</p><p><b>METHODS</b>The mean fluorescence intensity (MFI) of CD55 and CD59 expression on peripheral blood leucocyte subsets (lymphocytes, monocytes and neutrophils) was studied using flow cytometry, and carotid artery intima-media thickness was measured using B-mode ultrasonography in 23 healthy subjects (controls), 19 patients with type 2 diabetes (T2DM), and 43 patients with type 2 diabetes and macrovascular diseases (T2DM-M). The patients with T2DM-M were assigned to two subgroups based on whether statins were used: group with statins (n = 23) and group without statins (n = 20).</p><p><b>RESULTS</b>Compared with the controls and T2DM, the MFI of CD55 positive neutrophils was significantly lower in T2DM-M (P = 0.049 vs controls and P = 0.033 vs T2DM); similarly, the MFI of CD59 positive monocytes was also lower in T2DM-M (P = 0.038 vs controls and P = 0.043 vs T2DM). The MFI of CD59 positive neutrophils in T2DM-M was lower than in T2DM (P = 0.032). The levels of CD55 and CD59 were negatively associated with age and blood pressure (r = -0.245 - -0.352, P = 0.041 - 0.003), but not acute-phase reactants and carotid artery intima-media thickness. The levels of CD55 and CD59 increased after treatment with statins, but the results were not significantly different (P > 0.05).</p><p><b>CONCLUSIONS</b>CD55 and CD59 expressions on peripheral blood leucocytes are decreased in T2DM patients with macrovascular diseases. The results suggest that the decreased levels of complement regulatory proteins might play an important role in diabetic macrovascular diseases.</p>

Co-expression and synergic effect of human complement regulatory proteins DAF and MCP / 生物工程学报

Recombinant expression vector pcDNA3-DAFMCP-DP containing human membrane complement regulatory proteins (hCRPs) decay accelerating factor (DAF) and membrane cofactor protein (MCP) cDNA was constructed by using two independent promoters. After transfected into NIH3T3 cells by calcium phosphate-DNA precipitate method, NIH3T3 pcDNA3-DAFMCP-DP transfectants were obtained by G418 selection. Extraneous genes integration was identified by PCR. The co-expression of human DAF and MCP at both mRNA and protein levels was confirmed by using RT-PCR and Western blot analysis. Human DAF and MCP cDNA were integrated into NIH3T3 pcDNA3-DAFMCP-DP genomic DNA after continuous 30 times passages, indicating that NIH3T3 pcDNA3-DAFMCP-DP were stable cell lines. Human C-mediated cytolysis assays showed that NIH3T3 cells transfected stably with pcDNA3-DAF, pcDNA3-MCP, and pcDNA3-DAFMCP-DP were protected from C-mediated damage and co-expressed human DAF and MCP provided more excellent protection against C-mediated attack, which was compared with either DAF or MCP alone. These results suggest that the dicistronic vector could improve the efficiency of multi-gene delivery and benefit the synergic effect of human membrane complement regulatory proteins DAF and MCP.

Evaluation of allogenic complement-regulating proteins in the peripheral blood cells of chimeric rat models harboring human cord blood stem cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the mechanisms of surrogate tolerogenesis induced by chimeric donors.</p><p><b>METHODS</b>Hematopoietic stem cells (HSCs) from human cord blood were transplanted into fetal rats via intrauterine injection and infused into the liver of the neonatal rats to establish chimeric rat models with human HSCs. Four weeks after birth, flow cytometry was performed to analyze the percentages of human CD45 (hCD45), CD55 (hCD55) and CD59 (hCD59)-positive cells in the peripheral blood cells of the chimeric rats. The distributions of hCD55- and hCD59-positive cells in different hCD45/SSC gating regions were observed. The resistance of the peripheral blood lymphocytes to complements-mediated cytolysis was assessed by complement-dependent cytotoxicity (CDC) test in the chimeric rats and compared with that in control rats. The correlation between CDC and the human complement-regulating proteins in the chimeric rats were analyzed statistically.</p><p><b>RESULTS</b>On hCD45/SSC gating, the percentages of hCD55- and hCD59-positive cells in hCD45-positives region were (53.69-/+18.23)% and (31.8-/+27.5)%, accounting for (2.0-/+1.32)% and (0.76-/+0.56)% of the total cell population, respectively, which were significantly lower than the cell percentages in the extensive region (t=2.71, P=0.043 and t=3.64, P=0.015). The cytolytic rate of PBLs incubated with normal human serum was (22.32-/+15.10)% in the chimeric rats, significantly lower than that in the non-chimeric rats [(60.7-/+22.65)%, t=4.16, P<0.001). In the chimeric rats, hCD55-positive cell percentage was inversely correlated in the peripheral blood karyocytes the cytolysis rate in CDC (r=-0.679, P=0.031), and positively correlated to hCD45-positive cell percentage (r=0.658, P=0.038).</p><p><b>CONCLUSION</b>The hCD45-positives region is the cluster of chimeric human cells expressing human complement-regulating proteins. The peripheral blood lymphocytes from chimeric donor can resist the cytolysis mediated by human complement. The presence of allogenic CD55 and CD59 antigens in chimeric donors may be the basis of surrogate tolerogenesis for xenotransplantation.</p>

Activation of Intrarenal Complement System in Mouse Model for Chronic Cyclosporine Nephrotoxicity

PURPOSE: Local activation of the complement system plays a role in target organ damage. The aim of our study was to investigate the influence of cyclosporine (CsA)- induced renal injury on the complement system in the kidney. MATERIALS AND METHODS: Mice fed a low salt (0.01%) diet were treated with vehicle (VH, olive oil, 1mL/kg/day) or CsA (30mg/kg/day) for one or four weeks. Induction of chronic CsA nephrotoxicity was evaluated with renal function and histomorphology. Activation of the complement system was assessed through analysis of the expression of C3, C4d, and membrane attack complex (MAC), and the regulatory proteins, CD46 and CD55. CsA treatment induced renal dysfunction and typical morphology (tubulointerstitial inflammation and fibrosis) at four weeks. RESULTS: CsA-induced renal injury was associated with increased the expression of C3, C4d, and MAC (C9 and upregulation of complement regulatory proteins (CD 46 and CD55). Immunohistochemistry revealed that the activated complement components were mainly confined to the injured tubulointerstitium. CONCLUSION: CsA-induced renal injury is associated with activation of the intrarenal complement system.

Role of CD97(stalk) and CD55 as molecular markers for prognosis and therapy of gastric carcinoma patients / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

<p><b>OBJECTIVES</b>To explore the mechanism of development and aggressiveness in gastric carcinomas by investigating the expression and role of CD97 and its cellular ligand CD55 in gastric carcinomas.</p><p><b>METHODS</b>Tumor and corresponding normal mucosal tissue, collected from 39 gastric carcinoma patients, were examined by immunohistochemistry and RT-PCR for the expression of CD97 and CD55.</p><p><b>RESULTS</b>CD97(stalk) was strongly stained on scattered tumor cells or small tumor cell clusters at the invasion front of gastric carcinomas. The expression of CD97(stalk) was frequently observed in tumors of stage I and T1 gastric carcinoma patients. The expression of CD97(stalk) between Stage I and Stage II, III, IV specimens showed significant difference (P<0.05), between T1 and T2, T3, T4 specimens also showed significant difference (P<0.05). Specimens with tumor invasion depth limited in mucosa of T1 specimens showed higher positive CD55 expression than specimens with the same tumor invasion depth in T2, T3, T4 specimens, the expression of CD55 between T1 and T2, T3, T4 specimens was significantly different (P<0.05). There was strong correlation between the distribution patterns of CD97(stalk) and CD55 on tumor tissues (r=0.73, P<0.05). Signet ring cell carcinomas frequently contained strong CD97(stalk) and CD55-staining.</p><p><b>CONCLUSIONS</b>Our results suggest that CD97(stalk) is probably involved in the growth, invasion and aggressiveness of gastric carcinomas by binding its cellular ligand CD55. CD97(stalk) and CD55 could be useful as molecular markers for prognosis and therapy of gastric carcinoma patients.</p>

The effect of atorvastatin on the expression of CD55, CD59 in patients with hyperlipidemia / 中华心血管病杂志

<p><b>OBJECTIVE</b>To study the expressions of CD55 and CD59 in patients with hyperlipidemia and the effects of atorvastatin on it, and to identify the possible influential factors.</p><p><b>METHODS</b>We selected 67 patients with hyperlipidemia, and 24 healthy people matched in terms of age, sex and body weight as control. The expressions of CD55 and CD59 on white blood cells were detected by flow cytometry, and their relationships to blood lipids, complement activation indexes (C(5a), sC(5b-9)), inflammatory factors (high sensitivity C-reactive protein (hsCRP), TNF-alpha, IL-6 were analyzed. 24 patients with hyperlipidemia were treated with atorvastatin for 8-12 weeks and the expressions of CD55 and CD59 were measured before and after atorvastatin therapy.</p><p><b>RESULTS</b>The mean fluorescence intensity (MFI) of CD55 lymphocytes and monocytes were decreased in patients with hyperlipidemia compared with control (2.07 +/- 0.28 vs 2.29 +/- 0.44 and 3.45 +/- 1.02 vs 4.33 +/- 2.32, P < 0.01 and P < 0.05, respectively). CD55 positive lymphocyte MFI was negatively correlated with waist circumference, waist-hip ratio, hsCRP and C(5a). C(5a) was negatively correlated with the MFIs of CD55 positive lymphocytes, monocytes, granulocytes, and positively with TG and diastolic blood pressure. After atorvastatin therapy, the MFIs of CD59 positive lymphocytes, monocytes and granulocytes increased (4.34 +/- 1.16 vs 3.69 +/- 0.76, 4.52 +/- 1.36 vs 3.91 +/- 0.89, 5.67 +/- 1.72 vs 4.56 +/- 1.03, P < 0.05, < 0.05 and < 0.01 respectively), which were not correlated with changes of blood lipids.</p><p><b>CONCLUSIONS</b>The expression of CD55 is down-regulated in hyperlipidemia, which might be influenced by obesity, abdominal distribution of adipose tissue and inflammatory status of hyperlipidemia, but not by blood lipids. The expression of CD55 is related with complement activation; The expression of CD59 is up-regulated after atorvastatin treatment independently of blood lipids.</p>

Expression of three kinds of GPI-anchor proteins in paroxysmal nocturnal hemoglobinuria, aplastic anemia and myelodysplastic syndromes patients and their clinical implications / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the expressions of three kinds of glycosyl-phosphatidylinositol anchor proteins (GPI-AP), the CD(55), CD(59) and CD(87) on the peripheral granulocytes and the soluble u-PAR (su-PAR) level in serum from patients with paroxysmal nocturnal hemoglobinuria (PNH), aplastic anemia (AA), and myelodysplastic syndromes (MDS), and to analyse their clinical implications.</p><p><b>METHODS</b>Twenty-two PNH patients, including 4 complicated with thrombotic diseases and 5 with AA-PNH syndrome, 30 AA patients, including 9 being severe AA (SAA) and 11 chronic AA (CAA), 27 MDS-RA patients, and 20 healthy individuals were tested. The expressions of CD(55), CD(59) and CD(87) on peripheral granulocytes were analyzed with flow cytometry. Serum su-PAR was assayed by ELISA.</p><p><b>RESULTS</b>The CD(55)(+), CD(59)(+) and CD(87)(+) granulocytes in peripheral blood of 20 normal controls were all more than 90%. The expressions of three kinds of GPI-APs in 22 PNH patients were significantly decreased as compared with that in normal controls, AA patients and MDS-RA patients. The serum level of su-PAR in PNH group was higher than that of the other three groups. The expression of CD(87) was significantly decreased in thrombotic PNH patients as compared with that in non-thrombotic PNH patients. The expression of CD(87) was significantly decreased in AA patients than in normal controls. The expressions of three kinds of GPI-APs in 5 AA-PNH syndrome patients were remarkably reduced as compared with AA patients, but no significant difference was found for these indexes between AA-PNH syndrome and PNH patients and between 27 MDS-RA patients and 20 normal controls.</p><p><b>CONCLUSION</b>Measurement of CD(55), CD(59) and CD(87) expressions levels on the peripheral granulocytes and su-PAR in serum would be alternative approaches for diagnosis and differential diagnosis of PNH. Serum level of su-PAR may be helpful to monitor thrombosis in PNH patients.</p>

Rapid screening of PNH red cell populations using the gel test.

Paroxysmal nocturnal hemoglobinuria (PNH), an acquired clonal hematopoietic stem cell defect is underdiagnosed because of its atypical symptoms in some patients and because available methods, which are time consuming and complicated, are not widely used. The purpose of this study is to compare the results of the detection of PNH red cell populations using the PNH gel test and the Ham test. Fifty-eight blood samples obtained from 35 patients and 23 healthy blood donors were tested for PNH by the PNH gel test and the Ham test. It was found that 7 (20%) of the patients were positive for PNH by both tests. Twenty-three blood samples from healthy donors were all negative for PNH by both tests. The overall sensitivity and specificity of the gel test were 100%. This study showed that the PNH gel test was simple and could replace the Ham test as a screening test for PNH. This test would be especially easy to introduce in laboratories that are already using this system for blood grouping and antibody detection.

Expression of Complement Regulator Genes in Abeta1-42 Stimulated Human Neuroblastoma Cell

BACKGROUND: Endogenous complement inhibitors in the brain may protect against the neuroinflammation in Alzheimer's disease. Human neuroblastoma cells were stimulated by Abeta1 - 4 2 to investigate whether the expression of various complement regulator genes is upregulated. METHODS: SK-N-SH cells were incubated overnight with a single dose of 20 microM of Abeta1-42 or 0.5 ng/ml - 5 ng/ml of TNFalpha or both. Actinomycin D (2.5 microM) or cycloheximide (2.5 microM) was also added to the cell suspension. Messenger RNA expression of decay accelerating factor (DAF), membrane cofactor protein (MCP), CD59, complement-receptor 1(CR1), C1 inhibitor (C1-INH), C4-binding protein, factor H, factor I, clusterin and S-protein was measured by RT-PCR. RESULTS: Abeta1-42 and TNFalpha upregulated the expression of C1- INH significantly but increased expression of mRNA for factor H was not statistically significant. The expression of mRNAs for DAF and MCP was at low a level after stimulation. Factor I, CD59 and clusterin were not changed in their mRNA level. The mRNAs for S-protein, C4-binding protein and CR1 were not detected. Actinomycin D suppressed mRNA levels of C1-INH and CD59 significantly. Cycloheximide also inhibited the expression of both C1-INH and CD59. CONCLUSIONS: Early upregulated expression of C1-INH in Abeta1-42 stimulated neuroblastoma cell may contribute to a host defense mechanism against complement-mediated neuronal cell damage.

Expression of Complement Regulator Genes in Abeta1-42 Stimulated Human Neuroblastoma Cell

BACKGROUND: Endogenous complement inhibitors in the brain may protect against the neuroinflammation in Alzheimer's disease. Human neuroblastoma cells were stimulated by Abeta1 - 4 2 to investigate whether the expression of various complement regulator genes is upregulated. METHODS: SK-N-SH cells were incubated overnight with a single dose of 20 microM of Abeta1-42 or 0.5 ng/ml - 5 ng/ml of TNFalpha or both. Actinomycin D (2.5 microM) or cycloheximide (2.5 microM) was also added to the cell suspension. Messenger RNA expression of decay accelerating factor (DAF), membrane cofactor protein (MCP), CD59, complement-receptor 1(CR1), C1 inhibitor (C1-INH), C4-binding protein, factor H, factor I, clusterin and S-protein was measured by RT-PCR. RESULTS: Abeta1-42 and TNFalpha upregulated the expression of C1- INH significantly but increased expression of mRNA for factor H was not statistically significant. The expression of mRNAs for DAF and MCP was at low a level after stimulation. Factor I, CD59 and clusterin were not changed in their mRNA level. The mRNAs for S-protein, C4-binding protein and CR1 were not detected. Actinomycin D suppressed mRNA levels of C1-INH and CD59 significantly. Cycloheximide also inhibited the expression of both C1-INH and CD59. CONCLUSIONS: Early upregulated expression of C1-INH in Abeta1-42 stimulated neuroblastoma cell may contribute to a host defense mechanism against complement-mediated neuronal cell damage.