胸膜抗可溶性终末补体复合物的单克隆抗体对结核性、恶性和其他渗出液的鉴别诊断

根据以往对胸膜渗出液的免疫学研究,发现恶性胸液中IgG 低于非恶性胸液,结核性胸液中补体消耗增加;但此发现对常规诊断无特异性。抗可溶性终末补体复合物的单克隆抗体(SC5b-9)试用于区别结核、恶性和其他胸膜渗出液。SC5b-9可能是在补体激活中C5b-7期新生的C5b-9与S 蛋白粘接而产生。SC5b-9在结核引起的胸膜渗出液中的浓度显著高于血浆,提示胸膜腔补体激活。所有26例结核性渗出液患者胸水SC5b-9浓度均超过2.0mg/L;而20例恶性渗出的患者胸水SC5b-9浓度低于2.0mg/L。但类风湿、某些类肺炎、和经治疗的恶性渗出液SC5b-9     

末端补体SC5b-9抗C1q抗体及补体C3 C4在狼疮疾病活动性判定中的价值

目的 探讨末端补体SC5b-9、抗C1q抗体及补体C3和C4在狼疮疾病活动性判定中的价值.方法 采用酶联免疫吸附试验(ELISA)检测系统性红斑狼疮(SLE)组62例、疾病对照组35例和健康对照组35名血清中的末端补体SC5b-9和抗C1q抗体水平,并检测血清中补体C3和C4的水平,并与SLE患者临床表现、病情活动度及狼疮肾炎(LN)的病理分型进行相关性分析.结果 在SLE活动组中末端补体SC5b-9和抗C1q抗体水平均显著高于各对照组(均P<0.05).末端补体SC5b-9和抗C1q抗体与补体C3、C4呈负相关(P<0.05),与SLE疾病活动指数(SLEDAI)呈正相关(P<0.05).联合检测对疾病活动的判断的敏感性和特异性分别为95%和98%.末端补体SC5b-9及抗C1q抗体在狼疮增殖件肾炎中表达明显高于膜性肾炎(均P<0.05).结论 联合检测可提高疾病诊断和活动性判断的特异性和敏感性;末端补体SC5b-9和抗C1q抗体参与了狼疮增殖性肾炎的免疫发病机制.     

末端补体SC5b-9抗C1q抗体及补体C3 C4在狼疮疾病活动性判定中的价值

目的 探讨末端补体SC5b-9、抗C1q抗体及补体C3和C4在狼疮疾病活动性判定中的价值.方法 采用酶联免疫吸附试验(ELISA)检测系统性红斑狼疮(SLE)组62例、疾病对照组35例和健康对照组35名血清中的末端补体SC5b-9和抗C1q抗体水平,并检测血清中补体C3和C4的水平,并与SLE患者临床表现、病情活动度及狼疮肾炎(LN)的病理分型进行相关性分析.结果 在SLE活动组中末端补体SC5b-9和抗C1q抗体水平均显著高于各对照组(均P<0.05).末端补体SC5b-9和抗C1q抗体与补体C3、C4呈负相关(P<0.05),与SLE疾病活动指数(SLEDAI)呈正相关(P<0.05).联合检测对疾病活动的判断的敏感性和特异性分别为95%和98%.末端补体SC5b-9及抗C1q抗体在狼疮增殖件肾炎中表达明显高于膜性肾炎(均P<0.05).结论 联合检测可提高疾病诊断和活动性判断的特异性和敏感性;末端补体SC5b-9和抗C1q抗体参与了狼疮增殖性肾炎的免疫发病机制.     

末端补体SC5b-9抗C1q抗体及补体C3 C4在狼疮疾病活动性判定中的价值

目的 探讨末端补体SC5b-9、抗C1q抗体及补体C3和C4在狼疮疾病活动性判定中的价值.方法 采用酶联免疫吸附试验(ELISA)检测系统性红斑狼疮(SLE)组62例、疾病对照组35例和健康对照组35名血清中的末端补体SC5b-9和抗C1q抗体水平,并检测血清中补体C3和C4的水平,并与SLE患者临床表现、病情活动度及狼疮肾炎(LN)的病理分型进行相关性分析.结果 在SLE活动组中末端补体SC5b-9和抗C1q抗体水平均显著高于各对照组(均P<0.05).末端补体SC5b-9和抗C1q抗体与补体C3、C4呈负相关(P<0.05),与SLE疾病活动指数(SLEDAI)呈正相关(P<0.05).联合检测对疾病活动的判断的敏感性和特异性分别为95%和98%.末端补体SC5b-9及抗C1q抗体在狼疮增殖件肾炎中表达明显高于膜性肾炎(均P<0.05).结论 联合检测可提高疾病诊断和活动性判断的特异性和敏感性;末端补体SC5b-9和抗C1q抗体参与了狼疮增殖性肾炎的免疫发病机制.     

末端补体SC5b-9抗C1q抗体及补体C3 C4在狼疮疾病活动性判定中的价值

目的 探讨末端补体SC5b-9、抗C1q抗体及补体C3和C4在狼疮疾病活动性判定中的价值.方法 采用酶联免疫吸附试验(ELISA)检测系统性红斑狼疮(SLE)组62例、疾病对照组35例和健康对照组35名血清中的末端补体SC5b-9和抗C1q抗体水平,并检测血清中补体C3和C4的水平,并与SLE患者临床表现、病情活动度及狼疮肾炎(LN)的病理分型进行相关性分析.结果 在SLE活动组中末端补体SC5b-9和抗C1q抗体水平均显著高于各对照组(均P<0.05).末端补体SC5b-9和抗C1q抗体与补体C3、C4呈负相关(P<0.05),与SLE疾病活动指数(SLEDAI)呈正相关(P<0.05).联合检测对疾病活动的判断的敏感性和特异性分别为95%和98%.末端补体SC5b-9及抗C1q抗体在狼疮增殖件肾炎中表达明显高于膜性肾炎(均P<0.05).结论 联合检测可提高疾病诊断和活动性判断的特异性和敏感性;末端补体SC5b-9和抗C1q抗体参与了狼疮增殖性肾炎的免疫发病机制.     

末端补体SC5b-9抗C1q抗体及补体C3 C4在狼疮疾病活动性判定中的价值

目的 探讨末端补体SC5b-9、抗C1q抗体及补体C3和C4在狼疮疾病活动性判定中的价值.方法 采用酶联免疫吸附试验(ELISA)检测系统性红斑狼疮(SLE)组62例、疾病对照组35例和健康对照组35名血清中的末端补体SC5b-9和抗C1q抗体水平,并检测血清中补体C3和C4的水平,并与SLE患者临床表现、病情活动度及狼疮肾炎(LN)的病理分型进行相关性分析.结果 在SLE活动组中末端补体SC5b-9和抗C1q抗体水平均显著高于各对照组(均P<0.05).末端补体SC5b-9和抗C1q抗体与补体C3、C4呈负相关(P<0.05),与SLE疾病活动指数(SLEDAI)呈正相关(P<0.05).联合检测对疾病活动的判断的敏感性和特异性分别为95%和98%.末端补体SC5b-9及抗C1q抗体在狼疮增殖件肾炎中表达明显高于膜性肾炎(均P<0.05).结论 联合检测可提高疾病诊断和活动性判断的特异性和敏感性;末端补体SC5b-9和抗C1q抗体参与了狼疮增殖性肾炎的免疫发病机制.     

末端补体SC5b-9抗C1q抗体及补体C3 C4在狼疮疾病活动性判定中的价值

目的 探讨末端补体SC5b-9、抗C1q抗体及补体C3和C4在狼疮疾病活动性判定中的价值.方法 采用酶联免疫吸附试验(ELISA)检测系统性红斑狼疮(SLE)组62例、疾病对照组35例和健康对照组35名血清中的末端补体SC5b-9和抗C1q抗体水平,并检测血清中补体C3和C4的水平,并与SLE患者临床表现、病情活动度及狼疮肾炎(LN)的病理分型进行相关性分析.结果 在SLE活动组中末端补体SC5b-9和抗C1q抗体水平均显著高于各对照组(均P<0.05).末端补体SC5b-9和抗C1q抗体与补体C3、C4呈负相关(P<0.05),与SLE疾病活动指数(SLEDAI)呈正相关(P<0.05).联合检测对疾病活动的判断的敏感性和特异性分别为95%和98%.末端补体SC5b-9及抗C1q抗体在狼疮增殖件肾炎中表达明显高于膜性肾炎(均P<0.05).结论 联合检测可提高疾病诊断和活动性判断的特异性和敏感性;末端补体SC5b-9和抗C1q抗体参与了狼疮增殖性肾炎的免疫发病机制.     

末端补体SC5b-9抗C1q抗体及补体C3 C4在狼疮疾病活动性判定中的价值

目的 探讨末端补体SC5b-9、抗C1q抗体及补体C3和C4在狼疮疾病活动性判定中的价值.方法 采用酶联免疫吸附试验(ELISA)检测系统性红斑狼疮(SLE)组62例、疾病对照组35例和健康对照组35名血清中的末端补体SC5b-9和抗C1q抗体水平,并检测血清中补体C3和C4的水平,并与SLE患者临床表现、病情活动度及狼疮肾炎(LN)的病理分型进行相关性分析.结果 在SLE活动组中末端补体SC5b-9和抗C1q抗体水平均显著高于各对照组(均P<0.05).末端补体SC5b-9和抗C1q抗体与补体C3、C4呈负相关(P<0.05),与SLE疾病活动指数(SLEDAI)呈正相关(P<0.05).联合检测对疾病活动的判断的敏感性和特异性分别为95%和98%.末端补体SC5b-9及抗C1q抗体在狼疮增殖件肾炎中表达明显高于膜性肾炎(均P<0.05).结论 联合检测可提高疾病诊断和活动性判断的特异性和敏感性;末端补体SC5b-9和抗C1q抗体参与了狼疮增殖性肾炎的免疫发病机制.     

末端补体SC5b-9抗C1q抗体及补体C3 C4在狼疮疾病活动性判定中的价值

目的 探讨末端补体SC5b-9、抗C1q抗体及补体C3和C4在狼疮疾病活动性判定中的价值.方法 采用酶联免疫吸附试验(ELISA)检测系统性红斑狼疮(SLE)组62例、疾病对照组35例和健康对照组35名血清中的末端补体SC5b-9和抗C1q抗体水平,并检测血清中补体C3和C4的水平,并与SLE患者临床表现、病情活动度及狼疮肾炎(LN)的病理分型进行相关性分析.结果 在SLE活动组中末端补体SC5b-9和抗C1q抗体水平均显著高于各对照组(均P<0.05).末端补体SC5b-9和抗C1q抗体与补体C3、C4呈负相关(P<0.05),与SLE疾病活动指数(SLEDAI)呈正相关(P<0.05).联合检测对疾病活动的判断的敏感性和特异性分别为95%和98%.末端补体SC5b-9及抗C1q抗体在狼疮增殖件肾炎中表达明显高于膜性肾炎(均P<0.05).结论 联合检测可提高疾病诊断和活动性判断的特异性和敏感性;末端补体SC5b-9和抗C1q抗体参与了狼疮增殖性肾炎的免疫发病机制.     

末端补体SC5b-9抗C1q抗体及补体C3 C4在狼疮疾病活动性判定中的价值

目的 探讨末端补体SC5b-9、抗C1q抗体及补体C3和C4在狼疮疾病活动性判定中的价值.方法 采用酶联免疫吸附试验(ELISA)检测系统性红斑狼疮(SLE)组62例、疾病对照组35例和健康对照组35名血清中的末端补体SC5b-9和抗C1q抗体水平,并检测血清中补体C3和C4的水平,并与SLE患者临床表现、病情活动度及狼疮肾炎(LN)的病理分型进行相关性分析.结果 在SLE活动组中末端补体SC5b-9和抗C1q抗体水平均显著高于各对照组(均P<0.05).末端补体SC5b-9和抗C1q抗体与补体C3、C4呈负相关(P<0.05),与SLE疾病活动指数(SLEDAI)呈正相关(P<0.05).联合检测对疾病活动的判断的敏感性和特异性分别为95%和98%.末端补体SC5b-9及抗C1q抗体在狼疮增殖件肾炎中表达明显高于膜性肾炎(均P<0.05).结论 联合检测可提高疾病诊断和活动性判断的特异性和敏感性;末端补体SC5b-9和抗C1q抗体参与了狼疮增殖性肾炎的免疫发病机制.     

Complement activation in patients with diabetic nephropathy

AimEmerging evidence has indicated a role of the complement system in the pathogenesis of diabetic nephropathy (DN), although the pathways of complement activation and their clinicopathological relevance in DN are as yet unclear. The present study aimed to investigate levels of various complement components in plasma and urine of DN patients, and their correlation with clinicopathological parameters.MethodsA total of 68 biopsy-proven DN patients with plasma samples were recruited, including 50 patients who also had urine samples available. Seven complement components (C1q, MBL, Bb, C4d, C3a, C5a, soluble C5b-9) were measured by enzyme-linked immunosorbent assay (Elisa), and any associations between their levels and clinicopathological parameters were then investigated.ResultsIn DN patients, plasma levels of C1q, MBL, Bb, C4d, C3a, C5a and sC5b-9 were significantly higher than in diabetes patients without renal involvement, as were also urinary levels except for C1q, which showed no significant differences between the two groups. Also, urinary levels of C3a and C5a were significantly correlated with serum creatinine, urinary protein and estimated glomerular filtration rate, whereas urinary sC5b-9 was significantly correlated with the latter two (and not serum creatinine). In addition, urinary levels of MBL, Bb and C4d were significantly correlated with urinary protein, while C3a, C4d and Bb significantly correlated with the classification of glomerular lesions in DN.ConclusionIn DN patients, the complement system is activated and, of the three possible complement pathways, activation of the lectin and alternative pathways is associated with renal damage.     

Complement activation in hypercholesterolemia

BACKGROUND AND AIM: Inflammatory and lipid factors share an important role in atherosclerosis. This study evaluates their relations in dyslipidemic subjects. METHODS AND RESULTS: We compared the complement system (serum hemolytic activity CH50, C3 and C4 fractions and terminal complex sC5b-9) in 30 hypercholesterolemic patients with elevated cholesterol and decreased HDL-cholesterol levels, 30 normolipemic patients with clinical atherosclerosis and 30 matched normal subjects. In addition we evaluated the circulating immune complexes containing cholesterol (chol-CIC) on the assumption that they might be important in complement activation, and the circulating levels of the adhesion molecule ICAM-1 (sICAM-1) as a sign of endhotelial dysfunction. We found a significant increase of sC5b-9 (but not of CH50 and C3, C4) in the hypercholesterolemics compared with the other groups. The plasma sC5b-9 level was inversely and significantly related to HDL-chol (regression analysis), whereas no direct significant relation was found between sC5b-9 and cholesterol. Chol-CIC were also significantly increased in this group. The atherosclerosis patients also presented a significant increase of sC5b-9. Lastly, both patient groups displayed a significant increase of sICAM-1. CONCLUSIONS: We suggest that complement activation in dyslipidemics may be induced by their increased immune complexes. However, the decrease of complement regulatory proteins carried by HDL is another important factor, while complement changes may be related to variations of other humoral and cell systems (endothelium, coagulative/fibrinolytic system), whose involvement is suggested in our study by the changes of sICAM-1.     

The complement system in ischemic heart disease

The mechanisms by which tissue injury after acute myocardial infarction (AMI) occurs has not been fully elucidated. Recent evidence in experimental models has suggested involvement of the complement system in microvascular and macrovascular injury subsequent to AMI. With respect to angina pectoris, whether or not the complement system is activated is not clear. The present study assessed the role of complement as a mediator of myocardial inflammation by quantifying products of complement activation, including C3d, C4d, Bb, and SC5b-9 complexes, in 31 patients with AMI, 17 patients with unstable angina pectoris, 19 patients with stable angina pectoris, and 20 normal volunteers. The plasma C3d levels increased in patients with AMI and in those with unstable angina pectoris (p less than 0.01). The plasma levels of C4d, Bb, and SC5b-9 increased only in patients with AMI (p less than 0.01). The plasma SC5b-9 level was related to peak creatine phosphokinase (r = 0.71) and inversely related to the ejection fraction (r = -0.71). The plasma SC5b-9 level of patients with congestive heart failure was higher than that of patients without congestive heart failure in AMI. These results show that activation of complement system occurs after AMI and show an association of myocardial damage with complement activation. With respect to angina pectoris, the complement system is mildly activated in patients with unstable angina pectoris; however, the cardiac function of patients with unstable angina pectoris is not damaged. The complement system of patients with stable angina pectoris is not activated.     

The complement system in atherosclerosis

Complement is a term referring to a collection of plasma proteins, specific cellular receptors and cell surface regulatory molecules. Activation of the complement system to completion results in the formation of C5b-9 terminal complexes. These complexes have been observed in human atherosclerotic lesions by immunohistochemistry. Although the structure(s) which activate complement in lesions have not been defined, cholesterol and oxysterols exhibit this property in vitro. Endothelial cell damage leads to complement activation and endothelial cells overlying atherosclerotic lesions have been observed to contain C3 and C5b-9 antigens. Cardiac myocytes stain for complement proteins (C3, C4 and C5b-9) following myocardial infarction. Infarct size and extent of inflammatory cell infiltrates are diminished by decomplementation prior to experimentally-induced myocardial ischemia. Following myocardial infarction and ulceration of atherosclerotic lesions in human patients there is an increase in circulating complement activation products and a decrease in the level of native C1 through C4 proteins. Thus, it appears that complement plays a role in atherogenesis and its sequelae. Little is known however, about the pathophysiological effects complement activation products exert on lesion development, for example through modulation of macrophage functions, or how complement activation is regulated in lesions. Implications for complement in atherogenesis are discussed.     

Effects of complement activation in the isolated heart. Role of the terminal complement components.

The mechanisms of the complement-mediated myocardial injury associated with ischemia and reperfusion have not been elucidated fully. Complement activation may directly mediate injury through actions of the anaphylatoxins C3a and C5a or generation of the membrane attack complex C5b-9. A model was developed to examine the direct effects of complement activation on heart function, assess myocardial tissue damage, and determine which complement components mediate tissue injury. Isolated rabbit hearts were perfused with Krebs-Henseleit buffer by using a modified Langendorff apparatus. Human plasma was added to the perfusate as a source of complement. Rabbit tissue activates human complement. Treatment with 6% normal plasma resulted in complement activation as assessed by the generation of Bb, C3a, C5a, and SC5b-9. Functional changes in cardiac performance became apparent 7-15 minutes after plasma addition and developed fully over the next 20-30 minutes. The effects were dependent on the complement titer and included 1) an increase in the end-diastolic pressure, 2) a decrease in the developed pressure, 3) an increase in the coronary perfusion pressure, and 4) an increase in lymphatic fluid formation. These effects were not elicited when an inhibitor of complement activation (FUT-175) was present or when heat-inactivated plasma was used. The effects of complement activation on myocardial function could not be reproduced by treatment with recombinant human C5a, zymosan-activated plasma, or plasma selectively depleted of C8. Myocardial tissue accumulated sodium and calcium and lost potassium as a result of complement activation. Activation caused the release of creatine kinase from myocytes and an increase in the radiolabeled albumin space of the hearts. The data demonstrate that complement activation caused decrements in myocardial function and increased the coronary perfusion pressure and lymphatic fluid flow rate. The effects were not mediated by the anaphylatoxins but were dependent on the distal complement component C8, suggesting that C5b-9 was responsible for the physiological changes. Complement activation directly mediated tissue injury in a manner consistent with plasmalemmal disruption as a result of C5b-9 formation. The data suggest that the C5b-9 complex, which is known to form under conditions of ischemia, may contribute directly to myocardial cell injury.     

Immunohistochemical localization of the terminal C5b-9 complement complex in human aortic fibrous plaque

The terminal C5b-9 complex of the complement system was localized in 26 aortic, 3 iliac and 4 femoral human fibrous plaques using indirect immunofluorescence and immunoperoxidase. IgG, IgA, IgM, Clq, C3c, C4, C9 and fibrinogen were investigated simultaneously. All the fibrous plaques presented C5b-9 deposits appearing like thin threads in the fibrous cap and masses and spots in the amorphous areas. The extent and intensity were in agreement with the size of the fibrous plaques. The intimal thickenings presented less intense deposits which were absent in atherosclerosis-free samples. The C5b-9 deposits were frequently associated with immunoglobulins and complement components in the same areas. Whereas the demonstration of complement components reflected only a nonspecific trapping, the presence of assembled C5b-9 in the damaged tissues is more indicative of the involvement of complement activation in the tissue injury. The absence of C5b-9 in the atherosclerosis-free intima and its presence at lower intensity in the intimal thickenings than in the fibrous plaques suggest a pathogenic involvement in the chronic progression of the atherosclerotic lesion.     

Antiphospholipid antibodies and complement activation in patients with cerebral ischemia.

Antiphospholipid antibodies (aPL) have been linked to stroke and TIA. The mechanism for aPL-associated thrombosis is uncertain, but could be related to complement-mediated membrane damage. Indirect evidence for complement activation (low C4 levels) has been associated with aPL, with variable correlation with disease manifestations. We measured complement activation directly using an ELISA for SC5b-9 in 26 patients with stroke/TIA; 13 with and 13 without aPL. Patient plasma levels of SC5b-9 were measured along with standard positive and 5 normal control samples. Nine patients with, whereas only one without, aPL had an abnormal SC5b-9 level (p = 0.0018, Fisher's Exact Test). These data confirm a relationship between aPL and complement activation, which argues for an active autoimmune process in aPL-associated thrombosis and suggests that complement activation may play a pathogenic role.     

Synovial fluid levels of complement SC5b-9 and fragment Bb are elevated in patients with rheumatoid arthritis.

To determine whether complement turnover in synovial fluids of patients with rheumatoid arthritis (RA) reflects activation by the classical or alternative pathway, we used novel immunoassays to measure products of complement activation (the membrane attack complex SC5b-9 and the cleavage fragments Bb and C4d). Mean synovial fluid levels of SC5b-9 were more than 8 times higher in RA than in crystal-induced arthritis (gout and pseudogout) and over 16 times higher than in degenerative joint disease (DJD). Similarly, Bb levels were more than 3 times higher in RA synovial fluids than in crystal-induced arthritis and over 7 times higher than in DJD. Levels of C4d did not differ among the groups. SC5b-9 levels correlated with synovial fluid C3 anaphylatoxin (C3a), Bb, and C4d levels (r = 0.81, 0.62, and 0.51, respectively). In patients with RA, synovial fluid SC5b-9 levels correlated with C3a and Bb (r = 0.6 and 0.56, respectively) but not with C4d. Therefore, novel assays for complement activation indicate that both classical and alternative pathways are involved in complement turnover and that the alternative pathway contributes more to complement activation in RA than in DJD or crystal-induced arthritis.     

Antiphospholipid antibody-dependent C5b-9 formation

The relationship between the presence of antiphospholipid antibodies (APA) and the production of the terminal membrane attack complex (MAC) of complement (C5b-9) was studied. Serum samples from known high positive APA patients induced platelet activation and destruction which was inhibited by heat-inactivation of the sera. The response was restored if the heat-inactivated APA-positive sera were supplemented with normal sera. Adsorption of the APA-positive sera with phospholipid (PL)-coated polystyrene beads inhibited platelet destruction. Addition of monoclonal antibody (mAb) to C5b-9 (aE11) also inhibited platelet destruction, suggesting that the APA-dependent platelet destruction might be complement-mediated. Purified APA, in the presence of normal serum, induced C5b-9 formation and binding to PL-coated beads in a dose-dependent manner as detected by flow cytometry. Prospective analysis of 200 serum samples for C5b-9 production showed that all sera testing negative for the presence of APA also tested negative for C5b-9 production. All sera with high levels of IgG binding to PL (GPL) showed evidence of C5b-9 production. Sera with low or moderate GPL values showed varying levels of C5b-9 production. These data suggest that complement may play a key role in APA-dependent platelet activation, in vivo .