Levels Of Complement Regulatory Proteins Research Articles

Low-dose atorvastatin calcium combined with evolocumab: effect on regulatory proteins, lipid profiles, and cardiac function in coronary heart disease patients.

To assess the effects of combining low-dose atorvastatin calcium with evolocumab on complement regulatory protein levels, lipid profiles, and cardiac function in patients with coronary heart disease (CHD). A prospective randomized controlled study was conducted, with 180 CHD patients enrolled from Guang'anmen Hospital, China Academy of Chinese Medical Sciences, and the Second Hospital of Shanxi Medical University between February 2022 and April 2023. These patients were randomly assigned to either the control group (n = 90), receiving low-dose atorvastatin calcium, or the research group (n = 90), receiving a combination of low-dose atorvastatin calcium and evolocumab. The changes in cardiac function indices, levels of blood lipids and complement proteins, incidence of side effects, and cardiovascular events were compared between the two groups. After treatment, both groups exhibited reductions in blood lipid levels. However, the research group demonstrated significantly lower levels of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) compared to the control group (all P < 0.001). Additionally, improvements in cardiac function indices were observed in both groups, with the research group displaying greater enhancements in cardiac output (CO), stroke volume (SV), and left ventricular ejection fraction (LVEF). Furthermore, the levels of complement regulatory proteins, including CD45, CD46, CD55, and CD59, increased in both groups after treatment, with the research group exhibiting significantly higher levels (all P < 0.001). Notably, the research group also exhibited a lower incidence of cardiovascular events. The combined use of low-dose atorvastatin calcium and evolocumab effectively modulates complement regulatory protein levels, optimizes blood lipid profiles, and enhances cardiac function in patients with CHD. This combination therapy represents a promising approach for management of CHD.

Aspects of the Complement System in New Era of Xenotransplantation.

After producing triple (Gal, H-D and Sda)-KO pigs, hyperacute rejection appeared to no longer be a problem. However, the origin of xeno-rejection continues to be a controversial topic, including small amounts of antibodies and subsequent activation of the graft endothelium, the complement recognition system and the coagulation systems. The complement is activated via the classical pathway by non-Gal/H-D/Sda antigens and by ischemia-reperfusion injury (IRI), via the alternative pathway, especially on islets, and via the lectin pathway. The complement system therefore is still an important recognition and effector mechanism in xeno-rejection. All complement regulatory proteins (CRPs) regulate complement activation in different manners. Therefore, to effectively protect xenografts against xeno-rejection, it would appear reasonable to employ not only one but several CRPs including anti-complement drugs. The further assessment of antigens continues to be an important issue in the area of clinical xenotransplantation. The above conclusions suggest that the expression of sufficient levels of human CRPs on Triple-KO grafts is necessary. Moreover, multilateral inhibition on local complement activation in the graft, together with the control of signals between macrophages and lymphocytes is required.

Preclinical Anti-Tumor Activity of Hexabody-CD38 in Patient-Derived B Cell Lymphoma and Acute Myeloid Leukemia Xenograft Models

HexaBody®-CD38 (GEN3014) is a next-generation CD38-specific IgG1 molecule with a hexamerization-enhancing mutation that leads to highly efficient induction of complement-dependent cytotoxicity (CDC) upon binding to CD38 positive tumor cells. HexaBody-CD38 is designed to induce strong anti-tumor activity in patients with CD38-expressing hematological malignancies through CDC and other Fc-mediated effector functions. Previously we have shown that HexaBody-CD38 induces highly potent CDC-mediated cell death in multiple myeloma (MM), acute myeloid leukemia (AML), and B-cell non-hodgkin lymphoma (B-NHL) cells, including tumor cells in bone marrow samples from MM patients. In addition, HexaBody-CD38 demonstrated efficient ADCC and ADCP and induction of direct cell kill after Fc-crosslinking. Moreover HexaBody-CD38 induced strong inhibition of CD38 cyclase activity, which may contribute to reduction of immune suppression in the tumor microenvironment. In this study, we show that in a panel of 23 MM, AML and B-NHL cell lines HexaBody-CD38 induced CDC, with EC50 values on average 7-fold lower than those of the CD38-targeting mAb daratumumab, which is part of the standard of care for MM. Cytotoxic activity of HexaBody-CD38 showed a positive correlation with CD38 expression levels. HexaBody-CD38 was especially more potent than daratumumab in cell lines with lower CD38 expression. Sensitivity to HexaBody-CD38-induced CDC was correlated with lower expression levels of complement regulatory proteins, including CD46, CD55 and CD59. To exclude that the enhanced potency of HexaBody-CD38 resulted in lysis of healthy cell subsets known to express low levels of CD38, CDC in healthy donor leukocytes was assessed in vitro. HexaBody-CD38 (20 μg/mL) did not induce lysis of monocytes, B cells, T cells, granulocytes or erythrocytes, and only minor cytotoxicity of NK cells (median 13% lysis, range 9.5-55.1%). NK-cell lysis by daratumumab, assessed in parallel, was in the same range (median 8%, range 4.5-21.2%). Thus, HexaBody-CD38 shows superior potency in CD38-positive tumor cells while sparing healthy donor leukocytes and erythrocytes in vitro. The anti-tumor activity of HexaBody-CD38 in vivo was evaluated in patient-derived AML and B-NHL xenograft (PDX) models in nude mice. In a screen using 9 B-NHL PDX models in a 1-3 mice-per-treatment-group design, administration of two weekly doses of 5 mg/kg HexaBody-CD38 induced a strong anti-tumor response (relative tumor growth ≤10%, i.e. tumor stasis or tumor regression) in 2 models. Two models were classified as non-responder (relative tumor growth &amp;gt;70%) and 5 models could not be classified as either responder or non-responder (intermediates, relative tumor growth between 10 and 70%). A dose-response experiment in one of the responding models (Ly12638, 9 mice per group), confirmed potent anti-tumor activity of HexaBody-CD38, inducing complete tumor regression at a dose of 10 mg/kg (Figure 1A). In a screen using 5 AML PDX models in a 1-3 mouse-per-treatment-group design, HexaBody-CD38 (5 mg/kg) induced a strong anti-tumor response in one model. One model was classified as non-responder and the remaining 3 models could not be classified as either responder or non-responder (intermediates). A dose-response experiment in one of the intermediate models (AML11810), demonstrated statistically significant and dose-dependent anti-tumor activity of HexaBody-CD38 in an in vivo study using a classical 9 mice per treatment group design (Figure 1B). In summary, HexaBody-CD38 induced potent CDC in MM, B-NHL and AML cell lines, with superior potency compared to benchmark antibody daratumumab. HexaBody-CD38 was able to induce CDC in tumor cell lines with lower levels of CD38 expression, while sparing healthy leukocyte subsets. HexaBody-CD38 showed potent anti-tumor activity in vivo both in B-NHL and AML PDX models in nude mice. In these models, the contribution of mouse complement to the anti-tumor activity is limited and therapeutic activity is thought to be driven mainly through FcγR-mediated effector functions. This indicates that besides highly potent CDC, FcɣR-mediated effector mechanisms contribute to the preclinical activity of HexaBody-CD38 in hematological tumor models. These preclinical data support clinical investigation of HexaBody-CD38 in CD38 positive hematologic malignancies, including MM, AML, and B cell lymphomas. Figure Disclosures Hiemstra: Genmab: Current Employment, Current equity holder in publicly-traded company. Janmaat:Genmab: Current Employment, Current equity holder in publicly-traded company. Boross:Genmab: Current Employment, Current equity holder in publicly-traded company. van den Brakel:Genmab: Current Employment, Current equity holder in publicly-traded company. ten Hagen:Genmab: Current Employment, Current equity holder in publicly-traded company. van Dooremalen:Genmab: Current Employment, Current equity holder in publicly-traded company. Bosgra:Genmab: Current Employment, Current equity holder in publicly-traded company. De Goeij:Genmab: Current Employment, Current equity holder in publicly-traded company. Andringa:Genmab: Current Employment, Current equity holder in publicly-traded company. Kil:Genmab: Current Employment, Current equity holder in publicly-traded company. Sasser:Genmab: Current Employment, Current equity holder in publicly-traded company. Ahmadi:Genmab: Current Employment, Current equity holder in publicly-traded company. Satijn:Genmab: Current Employment, Current equity holder in publicly-traded company. Breij:Genmab: Current Employment, Current equity holder in publicly-traded company.

Expression levels of complement regulatory proteins (CD35, CD55 and CD59) on peripheral blood cells of patients with chronic kidney disease.

BackgroundAltered regulation of the complement system is associated with multiple kidney diseases. CD35, CD55 and CD59 regulate the complement system, and changes in their expression have previously been linked with kidney disease. This study assessed whether changes in the expression levels of these proteins are associated specifically with chronic kidney disease (CKD) to understand its pathogenesis.Materials and methodsSixty CKD patients and 60 age-matched controls were enrolled and divided into two groups: Group I (n=30 pediatric patients and n=30 controls) and Group II (n=30 adult patients and n=30 controls). The expression of CD35, CD55 and CD59 on peripheral blood cells was evaluated by flow cytometry as the proportion of positive cells expressing the marker and mean fluorescence intensity (MFI), also the relation of these markers to the stage of CKD was also evaluated.ResultsPediatric and adult CKD patients had significantly lower proportion of erythrocytes expressing CD35, CD55 and CD59 than healthy controls (P<0.001). In pediatric CKD patients, there was no significant difference in the three studied markers on neutrophils, lymphocytes and monocytes. The changes in expression of CD35, CD55 and CD59 on leukocytes were more pronounced in adult patients, who had lower proportion of CD59-positive neutrophils, CD35- and CD59-positive lymphocytes, and CD59-positive monocytes, as well as lower expression of CD59 on neutrophils and monocytes than adult controls (P<0.001, P=0.019, P<0.001, P=0.026, P<0.001 and P=0.003, respectively). The eGFR directly correlated with the proportion of positivity of some of those markers on peripheral leukocytes while there was inverse correlation between the disease stage and the same markers.ConclusionThere are alterations in the patterns of expression of complement regulatory proteins CD35, CD55 and CD59 on peripheral blood cells of patients with CKD compared with healthy controls.

Altered Expression of Complement Regulatory Proteins CD35, CD46, CD55, and CD59 on Leukocyte Subsets in Individuals Suffering From Coronary Artery Disease.

Studies conducted in animal models have suggested that membrane complement regulatory proteins play an important role in the pathophysiology of coronary artery disease (CAD). In this study, a total of 100 individuals, with stable CAD and 100 healthy controls, both groups predominantly male, were recruited. We evaluated the plasma levels of complement regulatory proteins (Cregs) CD35, CD46, CD55, and CD59 and their surface expression on granulocytes, lymphocytes, and monocytes by flow cytometry. The mRNA expression of these Cregs in total leukocytes was determined by quantitative PCR. The soluble forms of Cregs, C3c, Mannose binding protein-associated serine protease 2 (MASP-2), Platelet activating factor-acetyl hydrolase (PAF-AH), and inflammatory cytokines were quantified by ELISA. High plasma levels of C3c, indicative of complement activation, in addition to significantly low levels of Cregs, were observed in CAD patients. A significantly lower expression of CD46 and CD55 on the surface of lymphocytes, monocytes, and granulocytes and higher surface expression of CD35 and CD59 on granulocytes (p < 0.0001) was seen in CAD patients as compared to healthy donors. The high expression of CD59 on granulocytes positively correlated with the severity of disease and may serve as a potential marker of disease progression in CAD.

Loss of complement regulatory proteins on uninfected erythrocytes in vivax and falciparum malaria anemia.

Anemia is a major complication of malaria, driven largely by loss of uninfected RBCs during infection. RBC clearance through loss of complement regulatory proteins (CRPs) is a significant contributor to anemia in Plasmodium falciparum infection, but its role in Plasmodium vivax infection is unknown. CRP loss increases RBC susceptibility to macrophage clearance, a process that is also regulated by CD47. We compared CRPs and CD47 expression on infected and uninfected RBCs in adult patients with vivax and falciparum malaria and different anemia severities from Papua, Indonesia. Complement activation and parasite-specific complement-fixing antibodies were measured by ELISA. Levels of CR1 and CD55 were reduced in severe anemia in both falciparum and vivax malaria. Loss of CRPs and CD47 was restricted to uninfected RBCs, with infected RBCs having higher expression. There was no association among complement-fixing antibodies, complement activation, and CRP loss. Our findings demonstrate that CRP loss is a pan-species, age-independent mechanism of malarial anemia. Higher levels of CRP and CD47 expression on infected RBCs suggest that parasites are protected from complement-mediated destruction and macrophage clearance. Lack of associations between protective antibodies and CRP loss highlight that complement pathogenic and protective pathways are distinct mechanisms during infection.

Transcript levels of complement regulatory proteins (CD35 and CD59) in rheumatoid arthritis patients and their relationship with disease activity and prognosis

Event Abstract Back to Event Transcript levels of complement regulatory proteins (CD35 and CD59) in rheumatoid arthritis patients and their relationship with disease activity and prognosis Devyani Anand1, Maumita Kanjilal2, Satbir Kaur2, Uma Kumar2 and Nibhriti Das1* 1 All India Institute of Medical Sciences (AIIMS), Biochemistry, India 2 All India Institute of Medical Sciences (AIIMS), Medicine, India Objectives: Complement regulatory proteins (CRPs) protect the host from tissue injury mediated by activated complement system. In rheumatoid arthritis (RA) exaggerated complement activation is the key event, due to which CRPs CD35 and CD59 may influence the disease pathology and prognosis. Therefore, we aimed at elucidating the leukocyte-CD35 (L-CD35) and L-CD59 transcript levels and the relationship of these two CRPs with the disease activity of RA patients. Methods: 66 controls and 45 RA patients were recruited for this study. Out of 45 RA patients, 11 patients volunteered for the longitudinal study. L-CD35 and L-CD59 transcript levels were determined by real-time PCR and correlated with Circulating immune complexes (CIC) levels and Disease Activity Score-28 (DAS28). Results: Transcript levels of L-CR1 (p < 0.05) and L-CD59 (p < 0.01) were lowered in patients as compared to controls. In longitudinal study, L-CR1 transcript levels (p < 0.05) increased in patients which responded to treatment which correlated with lowered CIC levels (p < 0.05) and DAS28 scores (p < 0.05) at W24 as compared to W0. No significant difference was observed for L-CR1 transcript levels in non-responder group and for L-CD59 transcript levels in responder and non-responder group at W24 as compared to W0. Conclusions: This is the first study to assess the L-CR1 and L-CD59 transcript levels in RA patients. The findings indicate an intimate relation of L-CD35 transcript levels with the disease activity and prognosis in RA patients, and thus suggest L-CD35 transcript as a potential disease marker in RA. Keywords: Rheumatoid arthritis, complement regulatory proteins, Circulating immune complexes, prognosis, disease marker Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Immune-mediated disease pathogenesis Citation: Anand D, Kanjilal M, Kaur S, Kumar U and Das N (2013). Transcript levels of complement regulatory proteins (CD35 and CD59) in rheumatoid arthritis patients and their relationship with disease activity and prognosis. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00379 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Mar 2013; Published Online: 22 Aug 2013. * Correspondence: Prof. Nibhriti Das, All India Institute of Medical Sciences (AIIMS), Biochemistry, New Delhi, Delhi, 110029, India, nibhriti@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Devyani Anand Maumita Kanjilal Satbir Kaur Uma Kumar Nibhriti Das Google Devyani Anand Maumita Kanjilal Satbir Kaur Uma Kumar Nibhriti Das Google Scholar Devyani Anand Maumita Kanjilal Satbir Kaur Uma Kumar Nibhriti Das PubMed Devyani Anand Maumita Kanjilal Satbir Kaur Uma Kumar Nibhriti Das Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Early and extensive CD55 loss from red blood cells supports a causal role in malarial anaemia

BackgroundLevels of complement regulatory proteins (CrP) on the surface of red blood cells (RBC) decrease during severe malarial anaemia and as part of cell ageing process. It remains unclear whether CrP changes seen during malaria contribute to the development of anaemia, or result from an altered RBC age distribution due to suppressive effects of malaria on erythropoiesis.MethodsA cross sectional study was conducted in the north-east coast of Tanzania to investigate whether the changes in glycosylphosphatidylinositol (GPI)-anchored complement regulatory proteins (CD55 and CD59) contributes to malaria anaemia. Blood samples were collected from a cohort of children under intensive surveillance for Plasmodium falciparum parasitaemia and illness. Levels of CD55 and CD59 were measured by flow cytometer and compared between anaemic (8.08 g/dl) and non- anaemic children (11.42 g/dl).ResultsLevels of CD55 and CD59 decreased with increased RBC age. CD55 levels were lower in anaemic children and the difference was seen in RBC of all ages. Levels of CD59 were lower in anaemic children, but these differences were not significant. CD55, but not CD59, levels correlated positively with the level of haemoglobin in anaemic children.ConclusionThe extent of CD55 loss from RBC of all ages early in the course of malarial anaemia and the correlation of CD55 with haemoglobin levels support the hypothesis that CD55 may play a causal role in this disorder.

Increased deposition of C3b on red cells with low CR1 and CD55 in a malaria-endemic region of western Kenya: Implications for the development of severe anemia

Background Severe anemia due to Plasmodium falciparum malaria is a major cause of mortality among young children in western Kenya. The factors that lead to the age-specific incidence of this anemia are unknown. Previous studies have shown an age-related expression of red cell complement regulatory proteins, which protect erythrocytes from autologous complement attack and destruction. Our primary objective was to determine whether in a malaria-endemic area red cells with low levels of complement regulatory proteins are at increased risk for complement (C3b) deposition in vivo. Secondarily, we studied the relationship between red cell complement regulatory protein levels and hemoglobin levels.

Increased deposition of C3b on red cells with low CR1 and CD55 in a malaria-endemic region of western Kenya: Implications for the development of severe anemia

BackgroundSevere anemia due to Plasmodium falciparum malaria is a major cause of mortality among young children in western Kenya. The factors that lead to the age-specific incidence of this anemia are unknown. Previous studies have shown an age-related expression of red cell complement regulatory proteins, which protect erythrocytes from autologous complement attack and destruction. Our primary objective was to determine whether in a malaria-endemic area red cells with low levels of complement regulatory proteins are at increased risk for complement (C3b) deposition in vivo. Secondarily, we studied the relationship between red cell complement regulatory protein levels and hemoglobin levels.MethodsThree hundred and forty-two life-long residents of a malaria-holoendemic region of western Kenya were enrolled in a cross-sectional study and stratified by age. We measured red cell C3b, CR1, CD55, and immune complex binding capacity by flow cytometry. Individuals who were positive for malaria were treated and blood was collected when they were free of parasitemia. Analysis of variance was used to identify independent variables associated with the %C3b-positive red cells and the hemoglobin level.ResultsIndividuals between the ages of 6 and 36 months had the lowest red cell CR1, highest %C3b-positive red cells, and highest parasite density. Malaria prevalence also reached its peak within this age group. Among children ≤ 24 months of age the %C3b-positive red cells was usually higher in individuals who were treated for malaria than in uninfected individuals with similarly low red cell CR1 and CD55. The variables that most strongly influenced the %C3b-positive red cells were age, malaria status, and red cell CD55 level. Although it did not reach statistical significance, red cell CR1 was more important than red cell CD55 among individuals treated for malaria. The variables that most strongly influenced the hemoglobin level were age, the %C3b-positive red cells, red cell CR1, and red cell CD55.ConclusionIncreasing malaria prevalence among children >6 to ≤ 36 months of age in western Kenya, together with low red cell CR1 and CD55 levels, results in increased C3b deposition on red cells and low hemoglobin. The strong contribution of age to C3b deposition suggests that there are still additional unidentified age-related factors that increase the susceptibility of red cells to C3b deposition and destruction.

Thrombotic microangiopathy and intravenous immunoglobulin therapy

Sirs, I read with interest the article in this journal titled “Intravenous gamma globulin for thrombotic microangiopathy of unknown etiology” by Ito et al. [1], particularly the diagnosis of this patient and the effectiveness of intravenous immunoglobulin (IVIG). The reported patient exhibited hypertension, acute and chronic renal failure, normal ADAM metallopeptidase with thrombospondin type 1 motif 13 (ADAMTS13) activity, and an absence of inhibitory autoantibodies to ADAMTS13, which are clinical findings more common in atypical hemolytic uremic syndrome (HUS) than in thrombotic thrombocytopenic purpura (TTP) [2]. Complement dysregulation plays an important role in the pathogenesis of atypical HUS [2, 3]. Thirty to 50% of patients with atypical HUS exhibit gene mutations for regulators of complement activation, including complement factor H (CFH), membrane cofactor protein (MCP), or factor I (IF) [2–4]. In addition, some patients with atypical HUS without mutations in CFH, MCP, or IF may exhibit CFH autoantibodies [5]. Uncontrolled complement activation due to gene mutations or acquired antibodies to these complement regulatory proteins leads to glomerular and vascular endothelial injury and results in atypical HUS [2]. Although Ito et al. stated in the abstract that CFH deficiency was excluded in their patient, they did not provide detailed data regarding the complement system of this patient. Thus, it is possible that this patient might exhibit gene mutations for CFH, MCP, or IF or have antibodies to these complement regulatory proteins. Although IVIG has been used for TTP, the effectiveness of IVIG for TTP is still controversial [6, 7], and no report has demonstrated the efficacy of IVIG for atypical HUS [1]. Ito et al. reported an improved clinical condition and laboratory data following IVIG whereas plasma exchange (PE) was ineffective [1]. The beneficial effect of PE in atypical HUS is believed to be due to elevation of the levels of complement regulatory proteins by supplementation of deficient regulators or removal of antibodies to these regulators [4]. Therefore, PE is ineffective in patients with atypical HUS when it cannot increase the levels of complement regulatory proteins in these patients. On the other hand, IVIG has many immunoregulatory effects, including attenuation of complement activation [8]. IVIG acts as a scavenger for activated complement components such as C3b [8, 9] and may attenuate activation of alternative complement pathway regardless of CFH, MCP, or IF levels. Thus, IVIG may be effective for some patients with atypical HUS with complement dysregulation who are unresponsiveness to PE.

Serum levels of complement regulatory proteins in patients with IgA nephropathy

目的: IgA腎症はわが国の原発性糸球体腎炎のなかで最も頻度の高い腎炎である. 補体成分の糸球体沈着は知られているが, 血清中の補体成分の全体像は明らかにされていない. そこでわれわれは, 血清中の補体成分と補体制御蛋白がIgA腎症の病態に関与しているか否かについて検討した. 対象と方法: IgA腎症患者50名と健常者50名の補体価 (CH50) および血清補体成分を測定した. 血清C3とC4はlatex cohesive immunoassayで測定し, CH50はMayer法相対比濁法, Clqはnephelometry法, C5・C1 inhibitor・B・C4 binding protein・H・Iは一次元放射免疫拡散法で測定した. Mannose-binding proteinとproperdinは, ELISA法で測定した. IgA腎症患者を組織学的予後分類で4群 (予後良好群, 予後比較的良好群, 予後比較的不良群, 予後不良群) に分類し, 血清補体成分との関連性を検討した. 結果: IgA腎症患者では, 健常者と比較しCH50・C4・B・properdin・H・Iは有意に高値であった (p<0.01). IgA腎症患者では, C4とC1 inhibitor (p<0.05), C5とC4 binding protein (p<0.05) の間に有意な相関が認められた. しかし, 健常者ではそれらの相関は認められなかった. 予後分類の予後不良群は, 他の群に比べC4 binding proteinの有意な高値がみられた (p<0.05). 考察: IgA腎症患者では, 健常者と比較して血清補体成分および補体制御蛋白が高値であり, 各補体成分間で強い相関が認められた. また, C4 binding proteinが組織障害度と強い関連を認めた. これらのことより, 血清補体の変動は, 本症の病態を反映しているものと考えられた.

Suppression of Complement Regulatory Proteins (CRPs) Exacerbates Experimental Autoimmune Anterior Uveitis (EAAU)

This study was undertaken to explore the role of complement regulatory proteins (CRPs) in experimental autoimmune anterior uveitis (EAAU). We observed that the levels of CRPs, Crry and CD59, in the eyes of Lewis rats increased during EAAU and remained elevated when the disease resolved. The in vivo role of these CRPs in EAAU was explored using neutralizing mAbs, antisense oligodeoxynucleotides (AS-ODNs), and small interfering RNAs against rat Crry and CD59. Suppression of Crry in vivo at days 9, 14, or 19 by neutralizing mAb or AS-ODNs resulted in the early onset of disease, the exacerbation of intraocular inflammation, and delayed resolution. Suppression of CD59 was only effective when the Abs and ODNs were given before the onset of disease. The most profound effect on the disease was observed when a mixture of Crry and CD59 mAbs or AS-ODNs was administered. A similar effect was observed with a combination of Crry and CD59 small interfering RNA. There was no permanent histologic damage to ocular tissue after the inflammation cleared in these animals. Increased complement activation as determined by increased deposition of C3, C3 activation fragments, and membrane attack complex was observed in the eyes of Lewis rats when the function and/or expression of Crry and CD59 was suppressed. Thus, our results suggest that various ocular tissues up-regulate the expression of Crry and CD59 to avoid self-injury during autoimmune uveitis and that these CRPs play an active role in the resolution of EAAU by down-regulating complement activation in vivo.

Lymphocyte Phenotype Alterations, Pro-Inflammatory Cytokines and Acute Phase Proteins Following Repeated Bouts of Mountainous Hill-Running

We have previously shown that a single bout of exercise elicits a preferential mobilisation and subsequent extravasation of blood lymphocyte subsets expressing high levels of adhesion/activation (AA) molecules and low levels of complement regulatory proteins (Simpson et al. Med. Sci. Sports Exerc. 37, S336, 2005). Repeated bouts of exercise have the potential to accumulatively alter the trafficking of lymphocyte subset populations in the blood compartment. PURPOSE: To examine the effects of repeated bouts of mountainous hill-running on: blood lymphocyte subset counts; lymphocyte cell surface expression of glycoproteins; and plasma concentrations of TNFα and the acute phase proteins CRP, α-1-ACT, fibrinogen, fibronectin and haptoglobin. METHODS: Seven trained males (Age: 28±4yrs,: VO2max: 64 ± 3 ml·kg·mn−1) completed four bouts of hill-running on four consecutive days. Each bout consisted of 1126m ascent/descent over a distance of 24.5km and took 2–2.5h to complete. Blood samples were collected before, immediately after, 1h after completion and 24h after the start of each bout. Isolated lymphocytes were assessed for cell surface expression of subset markers (CD3, CD4, CD8, CD56), AA molecules (CD18, CD53, CD54), complement regulatory proteins (CD55, CD59) and the cell surface death receptor CD95 by flow cytometry. RESULTS: No statistical differences in run time or heart rate were found among the four exercise bouts. For all bouts, total lymphocyte counts and lymphocyte subset counts did not change immediately after exercise. At 1h post-exercise, CD3+, CD4+, CD8+ and CD56+ lymphocytes and the CD3+, CD8+ and CD56+ lymphocytes expressing CD18bright, CD53bright, CD54+, CD55dim, CD59dim and CD95 fell below the pre-exercise value after the first two bouts only. Lymphocyte subset counts and phenotypes returned to the pre-exercise values 24h after all bouts. Plasma CRP concentrations increased 24h after the first bout and remained elevated throughout the subsequent bouts. No changes in plasma concentrations of TNF? or the other acute phase proteins were found. CONCLUSION: Four consecutive days of hill-running elicited marked reductions in the number of lymphocyte subset populations expressing high levels of AA molecules and low levels of complement regulatory proteins. This effect occurred only after the first two exercise bouts, suggesting that a possible “carry-over” effect on lymphocyte trafficking during the subsequent exercise bouts occurred. Basal lymphocyte counts and phenotype characteristics, however, appeared to be restored in the blood compartment after 24h of recovery despite sustained elevations in plasma CRP activity.

Age-related changes in red blood cell complement regulatory proteins and susceptibility to severe malaria.

Severe malaria-associated anemia and cerebral malaria are life-threatening complications of Plasmodium falciparum infection. Red blood cell (RBC) complement regulatory proteins (CRPs) have been implicated in the pathogenesis of both. We sought to determine whether there are age-related changes in the expression of CRPs that could explain the susceptibility to severe malaria-associated anemia in young children and the susceptibility to cerebral malaria in older children and adults. In cross-sectional surveys in malaria-endemic and -nonendemic areas of Kenya and in Reims, France, the level of RBC CRPs was lowest in young children and increased into adulthood. In case-control studies, patients with cerebral malaria and matched control subjects had higher levels of RBC CRPs than did patients with severe anemia and matched control subjects, especially during convalescence. We conclude that RBC CRP levels vary with age and that the lower levels of these proteins in young children in areas of high transmission, such as western Kenya, may place these children at greater risk of severe malaria-associated anemia than cerebral malaria.

Expression of complement regulatory proteins on erythrocytes from patients with idiopathic focal segmental glomerulosclerosis

SUMMARY:Focal segmental glomerulosclerosis (FSGS) is a heterogeneous group of disorders with respect to aetiology, morphology, clinical course and response to treatment. The present study assessed the expression of complement receptor 1 (CR1), decay accelerating factor (DAF) and membrane inhibitor of reactive lysis (CD59) on the erythrocytes of FSGS patients using flow cytometry compared with their expression on the erythrocytes of minimal change nephrotic syndrome (MCNS) patients. Significantly reduced expression of CR1, DAF and CD59 was observed on the erythrocytes of FSGS patients compared with the reduced expression of CR1 and enhanced expression of DAF on the erythrocytes of MCNS patients. A significant inverse relationship was demonstrated between CR1 expression and proteinuria levels in FSGS patients (r = 0.55, P &lt; 0.01). A follow‐up study of 12 patients with FSGS after immunosuppressive therapy showed that the levels of complement regulatory proteins are significantly increased when the disease goes into remission. However, in patients not responding to immunosuppressive therapy, levels of these proteins remained low. MCNS patients showed significant increases in CR1 and decreases in DAF expression during remission of the disease.

Red cell surface changes and erythrophagocytosis in children with severe Plasmodium falciparum anemia

Severe anemia is one of the most lethal complications in children infected with Plasmodium falciparum. The pathogenesis of this anemia is not completely understood. Experimental data from malaria-infected humans and animal models suggest that uninfected red cells have a shortened life span. This study looked for changes in the red cell surfaces of children with severe malarial anemia that could explain this accelerated destruction. A prospective case-control study was conducted of children with severe P falciparum anemia (hemoglobin of 5 g/dL or lower) admitted to a large general hospital in western Kenya. Children with severe anemia were compared with children who had symptoms of uncomplicated malaria and with asymptomatic children. Cytofluorometry was used to quantify in vitro erythrophagocytosis and to measure red cell surface immunoglobulin G (IgG) and the complement regulatory proteins CR1, CD55, and CD59. Red cells from patients with severe anemia were more susceptible to phagocytosis and also showed increased surface IgG and deficiencies in CR1 and CD55 compared with controls. Red cell surface CD59 was elevated in cases of severe anemia compared with asymptomatic controls but not as compared with symptomatic controls. The surface of red cells of children with severe P falciparum anemia is modified by the deposition of IgG and alterations in the levels of complement regulatory proteins. These changes could contribute to the accelerated destruction of red cells in these patients by mechanisms such as phagocytosis or complement-mediated lysis. (Blood. 2000;95:1481-1486)

Levels of complement regulatory proteins, CD35 (CR1), CD46 (MCP) and CD55 (DAF) in human haematological malignancies.

Levels of the membrane complement regulatory proteins, C3b/C4b receptor (CR1, CD35), membrane cofactor protein (MCP, CD46), and decay-accelerating factor (DAF, CD55), expressed on cells from patients with haematological malignancies and normal subjects were assessed by flowcytometry using the respective monoclonal antibodies (mAbs). All myeloid and most lymphoid leukaemia samples tested were CR1-negative: two of the 42 leukaemia samples expressed minute amounts of CR1. Lack of CR1 in leukaemia cells was confirmed with two mAbs raised against CR1, 31R, and 243R, which recognized different epitopes and induced different degrees of CR1-mediated fluorescent shift on flow-cytometry in granulocytes and erythrocytes. MCP was increased in most chronic myelogenous leukaemia (CML) and chronic lymphocytic leukaemia (CLL), and was also increased in majority of acute nonlymphocytic leukaemia (ANLL), acute lymphocytic leukaemia (ALL) and non-Hodgkin's lymphoma (NHL). Levels of DAF were also high in CML and CLL, and were variable in other types of leukaemia: some were DAF-negative while others expressed extremely high levels of DAF. In CML patients, the high level of MCP and the lack of CR1 were normalized after medical treatment. These results are in agreement with the data obtained with human leukaemia cell lines, and support the hypothesis that CR1 is essentially a differentiated cell antigen and that a high level of MCP reflects some malignant transformation or an immature stage in blood cells.