Serum sCD40L Research Articles

Developmental Changes in Soluble CD40 Ligand

To determine if soluble CD40 ligand (sCD40L; formally CD154) levels vary with age and to identify age-dependent ranges in healthy pediatric and adult populations. sCD40L was measured in 25 neonates, 74 children (3 months-15 years of age) and 20 adults using an enzyme-linked immunosorbent assay. For age group comparisons, Mann-Whitney tests were performed. Correlation coefficients assessed relationships between plasma and serum sCD40L. Plasma sCD40L levels were higher in neonates than in all other age groups, (P <.001). All grouped pediatric plasma levels were significantly higher than in adults (P < .0001). There were no significant differences in plasma sCD40L between pediatric age groups. Serum levels were significantly higher in neonates than in any other age group (P < .0001). Pediatric and adult serum sCD40L levels were not significantly different. Plasma sCD40L levels are highest at birth and remain higher than those in adults throughout childhood. Reasons for such developmental changes remain to be investigated. Age-appropriate reference ranges should be used when sCD40L is being evaluated in pediatric disorders.

The alteration of serum soluble CD40 ligand levels in overt and subclinical hypothyroidism

There is controversy as to whether hypothyroidism increases cardiovascular risk. The effect of levothyroxine on the cardiovascular risk profile is also unclear. Recent studies suggest that there is evidence of inflammation and endothelial dysfunction in hypothyroidism. Soluble CD40 ligand (sCD40L) is a protein expressed mainly by activated platelets which have been found to be associated with cardiovascular events. The aim of our study was to investigate serum sCD40L levels and the effect of levothyroxine replacement on sCD40L levels in overt and subclinical hypothyroidism. We assessed lipid profile, serum sCD40L and hsCRP levels in 21 overt and 22 subclinical hypothyroid age-matched female patients with chronic autoimmune thyroiditis at baseline and one month after achieving euthyroidism by levothyroxine replacement, and compared them with the data from 22, age-matched, healthy controls. Overt and subclinical hypothyroid patients had decreased sCD40L levels compared to age-matched controls. The patients with subclinical hypothyroidism had slightly increased hsCRP levels, but the result was not statistically significant. In multiple regression analysis, FT3 and FT4 were found to be independent predictors of sCD40L levels. After levothyroxine replacement, serum sCD40L levels increased significantly in the patients with overt hypothyroidism. Although an increase was also observed in the subclinical hypothyroid group, it was not statistically significant. Levothyroxine replacement had no significant effect on hsCRP levels in the patients with overt hypothyroidism. However, the subjects with subclinical hypothyroidism showed a significant reduction in hsCRP levels after levothyroxine. The values of sCD40L and hsCRP in our study suggest that inflammatory pathways are complex and may be affected by different factors in hypothyroidism.

Perioperative changes of serum heart - type fatty acid binding protein in patients undergoing off - pump coronary artery by pass grafting

Objective To appraise the sensitivity of heart -type fatty acid binding protein （hFABP） for detection of myocardial ischernia in patients undergoing off - pump coronary artery bypass grafting （OPCABG） among cardiac markers. Methods 38 consecutive patients undergoing OPCABG were included in the study using standardized operative procedures and myocardial protection. Blood samples were taken preoperatively, during anastomoses, in the end of operation, at postoperative 6 h, 18 h and 36 h, respectively, and the serial serum levels of hFABP, cTnI, sCD40L, and CK - MB were assayed. Results Myocardial injury was detected with ECG or PCWP in six cases （ 16.7% ） during OPCABG, and the serial serum levels of hFABP, cTnl, sCD40L, and CK - MB were all higher in these patients than those without myocardial injury. Peak level of scrim hFABP appeared earlier and with higher amplitude than those of serum cTnI, sCD40L, and CK - MB. Conclusion The above results suggest that serum hFABP is a faster responding and more sensitive biochemical marker for the diagnosis of myocardial injury in patients undergoing OPCABG. Key words: heart- type fatty acid binding protein; myocardial ischernia; coronary artery bypass grafting

Increased Serum Levels of Circulating CD40 Ligand in Patients with Bullous Pemphigoid: Preliminary Results

Background: Autoimmune bullous diseases are characterized by autoantibodies against specific adhesion molecules of the skin and/or mucous membrane. While these autoantibodies are known to play a primary role in the disease manifestation, it remains unknown how disease-specific autoreactive B cells and autoantibodies are induced. Recent studies have indicated the importance of the CD40 and CD40 ligand (CD40L) receptor-ligand pair in the immunopathogenesis of autoimmune diseases. CD40L circulates in soluble form, and some reports suggest that serum soluble CD40L (sCD40L) levels are increased in various autoimmune diseases. Objectives: To determine serum sCD40L levels in patients with pemphigus vulgaris (PV) and bullous pemphigoid (BP), and to determine their correlation with clinical findings and laboratory findings. Patients and Methods: Sera from 10 PV patients, 35 BP patients and 12 normal controls were subjected to ELISA assays to measure serum levels of sCD40L, anti-desmoglein-3 antibody and anti-BP180 antibody. Results and Conclusions: Circulating sCD40L levels were significantly elevated in BP patients, but not in PV patients. Serum sCD40L levels increased in the early stage of disease onset and recurrence in BP patients. In conclusion, circulating sCD40L levels may be a useful marker for early activation of autoimmune diathesis and, furthermore, an effective therapeutic target in patients with BP.

Soluble CD40 Ligand as a Predictor of Coronary Artery Disease and Long-Term Clinical Outcomes in Stable Patients Undergoing Coronary Angiography

Background: In patients with acute coronary syndrome (ACS), elevated levels of soluble CD40 ligand (sCD40L) are associated with increased risk of cardiovascular events. We evaluated sCD40L levels and future cardiovascular events in patients not experiencing ACS. Methods: Serum sCD40L levels were measured in 909 patients undergoing angiography. A three-way matching scheme (age, gender and catheterization time period) identified 303 patients with coronary artery disease (CAD) who experienced a cardiac event within 1 year (CAD/event), 303 patients with CAD free of events (CAD/no event) and 303 patients without CAD and free of events (no CAD). Results: Average age was 64 ± 11 years; 74% were males. Median (± SE) sCD40L levels were higher for no CAD patients (335 ± 60 pg/ml) compared to CAD (248 ± 65 pg/ml, p = 0.01) and to CAD/event (233 ± 63 pg/ml, p < 0.001). There was no significant difference in median sCD40L levels between CAD/no event and CAD/event patients. Higher sCD40L quartiles were associated with a significant decrease in the risk of CAD/event versus no CAD (quartile 4 versus quartile 1: odds ratio = 0.59, p = 0.03). There was a nonsignificant trend towards a decreased risk of CAD as compared to no CAD, and for CAD/event versus CAD. Conclusions: In non-ACS patients, higher sCD40L levels were associated with a decreased risk of CAD. This novel interaction of sCD40L raises interesting questions for CAD pathogenesis.

Atherosclerosis risk factors in children of parents with the metabolic syndrome

Background Metabolic syndrome is a constellation of disorders that produces a high risk of atherosclerosis. Endothelial dysfunction is the key event in atherosclerosis and already present even in the childhood. The aim of the present study is to investigate inflammatory and radiological signs of atherosclerosis in children who have parents with the metabolic syndrome. Design and methods Fifty children of parents with the metabolic syndrome and 38 age- and sex-matched controls were studied. Anthropometric measurements, blood pressure assessment, echocardiography, flow-mediated vasodilatation (FMD) which is a non-invasive test for the evaluation of endothelial function and fasting blood measurements including blood glucose, insulin, total cholesterol, HDL cholesterol, triglyceride, hsCRP and soluble CD40 ligand were performed. Results Serum sCD40L and hsCRP levels were significantly higher in the study group compared to the controls. FMD values did not differ between the study and control groups. Increased serum sCD40L levels were positively correlated with body mass index, waist hip ratio, LDL/HDL cholesterol ratio, and the number of metabolic syndrome components in parents, whereas showed negative correlation with the serum HDL cholesterol levels. High hsCRP levels were positively correlated with body mass index and the number of metabolic syndrome components. Multiple regression analysis demonstrated that the number of metabolic syndrome components in parents presented as being a significant predictor of the serum sCD40L and hsCRP levels of their children. Conclusion Our results suggest that children of patients with metabolic syndrome have higher values of the serum markers of inflammation, which may be associated with increased risk for development of cardiovascular disease.

SCD40 Ligand Determined in Maternal and Umbilical Cord Blood in Pregnancies Complicated by Pre-Eclampsia with and without Intrauterine Growth Retardation

Objective: The aim of this study was determination and comparative analysis of the maternal and umbilical cord sCD40L serum levels in pregnancies complicated by pre-eclampsia with and without intrauterine growth retardation (IUGR) and in normotensive pregnancies. Patients and Methods: The study was carried out on 16 patients with singleton pregnancies complicated by severe pre-eclampsia with appropriate-for-gestational-age weight infants and 14 pregnant patients with severe pre-eclampsia complicated by IUGR. The control group consisted of 13 healthy normotensive delivering patients. Five milliliters of blood were taken by venipuncture from each pre-eclamptic patient and from each woman from the control group before active phase of labor and 5 ml of umbilical vein blood were taken immediately after delivery and collected in sterile tubes. Maternal and umbilical serum sCD40L concentrations were estimated using a sandwich ELISA assay. Results and Conclusions: Our results reveal the higher levels of maternal and umbilical sCD40L serum levels in pregnancy complicated by pre-eclampsia with and without IUGR. The mean maternal values were 4.022 ± 2.399 ng/ml in group P, 3.914 ± 2.824 ng/ml in group PI and 0.885 ± 0.064 ng/ml in healthy controls. The mean umbilical values were 2.633 ± 1.984 ng/ml in group P, 2.703 ± 1.996 ng/ml in group PI and 1.112 ± 0.436 ng/ml in the control group. It seems that these higher concentrations of sCD40L protect maternal immune cells bearing CD40 receptor from Fas-mediated apoptosis. Our findings may suggest also enhanced platelet activation in pre-eclamptic patients. It may be one of the factors responsible for the enhanced procoagulatory and proinflammatory properties, and increased cytokine production, and endothelial cell dysfunction in pregnancies complicated by pre-eclampsia.

Influence of pre-analytical and analytical factors on soluble CD40L measurements

The soluble form of CD40L (CD40 ligand), a pro-atherogenic mediator, has emerged as a diagnostic and prognostic marker for cardiovascular events. However, as platelets can shed CD40L upon activation, accurate measurement has proved challenging. The present study addresses the controversy regarding the appropriate specimen and preparation for laboratory evaluation of blood sCD40L (soluble CD40L). Serum and plasma (collected in EDTA, citrate or heparin) were collected from healthy volunteers (n=20), and sCD40L was analysed by ELISA immediately or after one to three freeze-thaw cycles and at different centrifugation speeds. Urine sCD40L levels were measured in subjects with low- and high-plasma sCD40L levels. Serum sCD40L levels (5.45+/-4.55 ng/ml; P<0.001) were higher than in citrate, EDTA or heparin plasma (1.03+/-1.07, 1.43+/-1.03 or 1.80+/-1.25 ng/ml respectively), with no significant differences between plasma preparations. Increasing g values (200-13000 g), which gradually deplete plasma of platelets, yielded lower sCD40L levels. Repeated freeze-thaw cycles significantly (P<0.05) increased sCD40L concentrations in platelet-rich, but not platelet-depleted, plasma (up to 2.4-fold). Bilirubin and haemoglobin interfered positively, and triacylglycerols (triglycerides) and cholesterol quenched CD40L signalling. No sCD40L was detected in urine samples. In conclusion, serum yields higher sCD40L concentrations than plasma; accurate measurements of sCD40L require exclusion of platelets and avoiding their post-hoc activation. Samples with high concentrations of bilirubin, haemoglobin and/or triacylglycerols should be excluded, as these substances interfere with the assay.

The clinical investigation of testing seven cycling markers in patients with coronary heart disease by flow cytometry

目的 探讨7种外周血循环标志物在不同类型冠心病患者中的临床应用价值.方法 对190例可疑冠心病患者,行选择性冠状动脉造影术,确定只少一支冠状动脉直径狭窄≥50%为冠状动脉造影阳性,其中冠状动脉造影阳性组144例,包括稳定性心绞痛(SAP)患者62例,ACS患者82例;冠状动脉造影阴性组46例.应用流式细胞术进行患者血清白细胞介素-6(IL-6)、白细胞介素-8(IL-8)、sCD40L、单核细胞趋化蛋白-1(MCP-1)、可溶性P-选择素(P-selectin)、组织纤溶酶原激活剂(t-PA)、可溶性血管细胞黏附分子(sVCAM-1)的测定.结果 急性冠状动脉综合征组血清sCD40L水平(8.6±5.1)ng/L较稳定性心绞痛组(5.7±4.4)ng/L和冠状动脉造影阴性组(4.1±3.3)ng/L明显升高(P＜0.01),其余标志物在各组间均有统计学意义(P＜0.01).Logistic回归分析显示,冠脉造影阳性组和阴性组,OR值最大的是sCD40L(OR=1.41,95%CI 1.08～1.85);而在稳定性心绞痛组和急性冠脉综合征组间,OR值最大的是sP-selectin(OR=1.06,95%CI 1.02～1.10),而IL-6在两种分组中,也有统计学意义.结论 IL-6、sCD40L和sP-selectin作为冠心病严重程度的估计和监测可能优于其他几种标志物,同时也为进一步解释急性冠状动脉综合征患者斑块不稳定性的病理生理学机制提供有用的佐证。

Randomized comparison of the effects of ASA plus clopidogrel versus ASA alone on early platelet activation in acute coronary syndromes with elevated high-sensitivity C-reactive protein and soluble CD40 ligand levels

High-sensitivity C-reactive protein (hsCRP) and soluble cluster of differentiation 40 ligand (sCD40L) have been established as effective markers of inflammation in predicting the risk for adverse outcomes in patients with acute coronary syndromes (ACSs). Activated platelets secrete certain inflammatory mediators such as P-selectin and sCD40L, which play a role in the pathogenesis of ACSs. Although acetylsalicylic acid (ASA) has been found to be an effective treatment of ACSs, the addition of clopidogrel bisulfate has been found tofurther improve clinical outcomes as a result of additional antiplatelet and anti-inflammatory action. Few data exist concerning the effects of dual antiplatelet therapy on these markers in patients with ACSs. The aim of this study was to assess the effectiveness and clinical significance of clopidogrel administration in patients with ACSs without ST segment elevation treated with ASA. This randomized, single-blind, controlled trial was conducted at the First Department of Cardiology, Hippokration Hospital, Athens, Greece. Inpatients aged>or=21 years with ACSs without ST segment elevation were randomly assigned to 1 of 2 groups: ASA 325 mg/d for 1 week, followed by ASA (100 mg/d) plus clopidogrel (300-mg loading dose followed by 100 mg/d) for 36 weeks (ASA+Clop group) or ASA alone (325 mg/d for 1 week, followed by 75 mg/d for 36 weeks) (ASA group). Levels of serum sCD40L, hsCRP, and P-selectin were determined on admission and at 8 hours, 48 hours, and 6 days of treatment. By means of clinical follow-up, Kaplan-Meier free-of-major adverse cardiovascular events (MACES) plots were used to assess the prevalence of MACES, including cardiovascular-related death, in patients with and without high levels of hsCRP (>or=3 mg/L) and sCD40L (>or=5 microg/L) for 52 weeks. A total of 86 patients were enrolled (71 men, 15 women; mean [SD] age, 68 [3] years; mean [SD] weight, 86 [18] kg; white race, 86 [100%]; 43 patients per group). Both groups had similar initial clinical characteristics and P-selectin levels. Baseline hsCRP and sCD40L levels were correlated with baseline P-selectin levels (hsCRP, r2=0.099 The results of this small study suggest that early activation of platelets, as measured using P-selectin levels, was effectively inhibited by the addition of clopidogrel to a regimen of ASA in the subgroup of patients with ACSs and intense activation of platelets (defined as high hsCRP and sCD40L levels). In patients without high hsCRP and sCD40L levels, the addition of clopidogrel did not have a significant effect on P-selectin levels.

Association of soluble CD40 ligand with carotid atherosclerosis in Japanese type 1 diabetic patients

It has recently been shown that the soluble form of CD40 ligand (sCD40L) interacts with CD40 on vascular cells, leading to a variety of proinflammatory responses, and that serum sCD40L levels can be a predictive marker of cardiovascular events. The aim of this study was to estimate sCD40L levels in type 1 diabetic patients to examine a possible association with carotid atherosclerosis. Human sCD40L levels in serum and intima-media thickness (IMT) of carotid artery were examined in 80 Japanese type 1 diabetic patients (27 men and 53 women, age 22.8+/-3.4 years (mean+/-SD), duration of diabetes 13.2+/-6.1 years) and 20 healthy age-matched non-diabetic individuals. Serum sCD40L levels were significantly (p=0.0185) higher in subjects with type 1 diabetes (2.10+/-1.33 ng/ml) compared with non-diabetic subjects (1.35+/-0.88 ng/ml). The greatest IMT (Max-IMT) and averaged IMT (Mean-IMT) were also significantly greater in patients with type 1 diabetes than in control subjects (0.73+/-0.14 vs 0.64+/-0.07 mm, p=0.0041, 0.63+/-0.09 vs 0.57+/-0.06 mm, p=0.0066, respectively). Levels of sCD40L were statistically significantly associated with Max-IMT (r=0.383, p<0.001) and Mean-IMT (r=0.275, p=0.0058). Furthermore, stepwise multivariate regression analyses demonstrated that sCD40L is a determinant of both Max- and Mean-IMT, independently of conventional risk factors. It is suggested that increased levels of serum sCD40L are associated with accelerated atherosclerotic change observed in young patients with type 1 diabetes.

The levels of circulating markers of atherosclerosis and inflammation in subjects with different degrees of body mass index: Soluble CD40 ligand and high-sensitivity C-reactive protein

Background It is well demonstrated that obesity is an independent risk factor for cardiovascular diseases. Recent studies have shown that obesity, insulin resistance and atherosclerosis are closely related phenomena in which low-grade inflammatory state and prothrombotic condition has pivotal roles. It has been shown that CD40-soluble CD40 ligand (sCD40L) interactions might constitute an important mediator for vascular inflammation. The aim of the present study was to assess sCD40L in relation to hs-CRP and cardiovascular risk factors in relation to body mass index (BMI). Materials and methods Serum sCD40L and hs-CRP concentrations were measured in 52 obese patients and 28 non-obese subjects by ELISA. Insulin resistance was calculated by homeostasis model assessment-insulin resistance (HOMA-IR). We divided the participants into three groups depending in their BMI levels (Group 1: BMI < 25 kg/m 2, Group 2: BMI 30–34.9 kg/m 2, Group 3: BMI ≥ 35 kg/m 2). Results We determined that the mean sCD40L of group 3 was significantly higher than group 1 and group 2 ( p < 0.05, p < 0.05, respectively). However, there was no significant correlation between plasma sCD40L levels and BMI. Plasma levels of hs-CRP were higher in obese group than the non-obese group ( p < 0.001). The levels of sCD40L were not significantly different between the two groups. The mean hs-CRP levels increased gradually in accordance with groups of BMI, there was a strong correlation between hs-CRP levels and BMI (r = 0.724, p < 0.001). There was no significant correlation between sCD40L and hs-CRP levels in all participants. Conclusions It is still a subject for debate whether sCD40L levels are increased or not in obesity. However, the results of this study showed that sCD40L is substantially increased in patients with severe obesity. In terms of causality, the relatively small sample size and cross-sectional design of this study are considered to be the limitation factors.

Serum Levels of Platelet Released CD40 Ligand Are Increased in Early Onset Occlusive Carotid Artery Disease

Objective: Soluble CD40 ligand (sCD40L) has been suggested as a key mediator between inflammation and atherosclerosis, and the CD40-CD40L interaction has a role in atherosclerotic lesion progression. We evaluated if platelet released serum sCD40L and sCD40 levels differ between patients with early onset occlusive carotid artery disease and age-matched controls. Methods: sCD40L and sCD40 levels were measured in serum samples of 60 patients with occlusive carotid artery disease and 30 age-matched controls using ELISA. Degree of stenosis of the internal carotid artery (ICA), and intima-media thickness (IMT) in the common carotid artery were measured by high resolution ultrasound. Values are given as mean ± SD. Results: Mean age was 50.9 ± 3.5 and 50.1 ± 3.5 years in the patient and control groups. IMT was significantly thicker in patients than in controls (0.89 ± 0.14 vs. 0.78 ±0.12 mm, p = 0.0003). Serum levels of sCD40L were significantly higher (6.9 ± 5 vs. 4.5 ± 3.0 ng/mL, p = 0.038) in patients, whereas sCD40 did not differ significantly between patients and controls (85 ± 56.9 vs. 79.3 ± 18.7 pg/mL, p = 0.34). IMT did not correlate with sCD40L or sCD40 levels (R = −0.03, p = 0.77; and R = 0.109, p = 0.308, respectively). Conclusions: sCD40L but not sCD40 levels are significantly higher in patients with occlusive carotid artery disease. Platelet derived sCD40L may be a key mediator among inflammation, thrombosis and atherosclerosis.

Plasma, Serum, and Platelet Expression of CD40 Ligand in Adults With Cardiovascular Disease

The application of soluble CD40 ligand (sCD40L) as a biomarker has garnered great scientific and clinical interest. However, there are many uncertainties with regard to the biology of sCD40L. Although presumed to be a marker of platelet activation, relative levels in plasma, serum, and platelet expression are unknown, as is the optimal method for its measurement. We measured CD40L from serum, platelet-poor plasma, and platelet surface in adults who had stable cardiovascular disease (CVD) and those who had unstable CVD (n = 40). Plasma sCD40L did not differ significantly between groups. Serum sCD40L was significantly lower (1.4 +/- 1.3 vs 5.2 +/- 3.7 ng/ml, p <0.001) and platelet membrane CD40L expression was higher (1.4 +/- 0.7% vs 0.9 +/- 0.6%, p = 0.03) in unstable compared with stable CVD. When the 2 groups were considered together, there was a significant correlation between plasma and serum sCD40L levels (rho = 0.4, p = 0.02) and negative correlations between plasma (rho = -0.3, p = 0.04) and serum (rho = -0.4, p = 0.01) sCD40L levels with platelet membrane CD40L expression. In unstable CVD, the correlation between sCD40L measurements was poor. Consistent with enhanced platelet activation, there was a positive correlation between platelet aggregation and surface CD40L expression (rho = 0.5, p = 0.02) and between platelet expression of CD40L and P-selectin (rho = 0.4, p = 0.05) in unstable CVD. There was no correlation between CD40L and platelet count or C-reactive protein. Only surface expression of CD40L compared with platelet-derived (plasma) or total (serum) CD40L level proved a reliable marker of platelet function in patients who had stable CVD and those who had unstable CVD. In conclusion, our data demonstrate the complex nature of CD40L and highlight the distinct processes of expression, shedding, and clearance of this ligand in patient populations.

Analysis of serum soluble CD40 ligand in patients with influenza virus-associated encephalopathy

CD40 ligand (CD40L) is mainly expressed on activated platelets and CD4 + T cells, and it can be cleaved from the cell surface, releasing a soluble CD40L (sCD40L). Most sCD40L is derived from activated platelets. A previous paper revealed that the platelet number of patients with influenza virus-associated encephalopathy (IE) was correlated with the outcome. We determined the utility of sCD40L as a predictor for the prognosis of IE. We measured the serum concentration of sCD40L and the platelet number on the day of hospitalization in 34 patients with IE, 16 with influenza virus-associated febrile seizures (IFS), 19 with influenza virus infection without complications (Flu), and 7 with Epstein–Barr virus (EBV) infection. The serum sCD40L concentrations in IE and IFS were significantly lower than those in controls, Flu, and EBV infections. Serum sCD40L concentrations in the IE group were 0.70 ± 0.43 ng/ml for deceased patients, 1.73 ± 1.36 ng/ml for those with sequelae, and 3.85 ± 2.91 ng/ml for those without sequelae. There was no significant difference in platelet number between IE patients with and without sequelae, while the platelet number of deceased patients with IE was significantly lower than in controls, Flu, and IFS. Serum sCD40L concentration on the day of hospitalization was more correlated with the outcome of IE than platelet number. Our findings suggest that the serum sCD40L concentration during acute IE is important for predicting the prognosis at an early stage.

Enhanced soluble CD40 ligand contributes to endothelial cell dysfunction in vitro and monocyte activation in patients with diabetes mellitus: effect of improved metabolic control

Inflammation plays a pathogenic role in the development of accelerated atherosclerosis in diabetes. Soluble CD40 ligand (sCD40L) is enhanced in diabetes; however, the molecular mechanisms linking sCD40L to accelerated atherosclerosis in diabetes are still unclear. We tested the hypothesis that sCD40L may be involved in the vascular complications in diabetes and exerts its effect by triggering inflammatory reactions on mononuclear and endothelial cells (ECs). We studied 70 patients, 40 with type 2 and 30 with type 1 diabetes, with a history or physical examination negative for cardiovascular disease, and 40 non-diabetic and 30 healthy subjects, matched with the type 2 and type 1 diabetic patients, respectively. Plasma and serum sCD40L, and plasma soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, E-selectin and monocyte chemo-attractant protein-1 (MCP-1) were measured. Adhesion molecules and MCP-1 release, the ability to repair an injury in ECs, and O2- generation in monocytes were analysed in vitro after stimulation with serum from patients or controls. Type 2 and type 1 diabetic patients had significantly higher sCD40L levels than controls. Furthermore, high sCD40L was associated with in vitro adhesion molecules and MCP-1 release, impaired migration in ECs and enhanced O2- generation in monocytes. Improved metabolic control was associated with a reduction of plasma sCD40L by 37.5% in 12 type 1 diabetic patients. Furthermore, elevated sCD40L in diabetic patients was significantly correlated with HbA1c levels. Upregulation of sCD40L as a consequence of persistent hyperglycaemia in diabetic patients results in EC activation and monocyte recruitment to the arterial wall, possibly contributing to accelerated atherosclerosis development in diabetes.

Analysis of serum soluble CD40 ligand (sCD40L) in the patients undergoing allogeneic stem cell transplantation: platelet is a major source of serum sCD40L

CD40 ligand (CD40L) is expressed not only on activated T cells but also on activated platelets. A soluble CD40 ligand (sCD40L) is released from the activated T cells and platelets by ill-defined proteolytic process in vitro. It has been reported that sCD40L is elevated in the serum of patients with systemic lupus erythematosus, unstable angina, essential thrombocythemia, and autoimmune thrombocytopenic purupura. However, source of sCD40L in vivo remains to be elucidated. We investigated the serial sCD40L in the serum in patients undergoing allogeneic stem cell transplantation and compared with the platelets number and soluble IL2R, which is a marker of activated T cells. The value of sCD40L was well correlated with platelet number or thrombopoiesis. In cases of severe graft vs. host disease with markedly increased sIL2R, sCD40L was not increased in vivo. These results indicate that sCD40L in vivo is released mainly from the platelets or in the process of platelet production but not from the activated T cells.

Increased CD40 ligand and platelet–monocyte aggregates in patients with type 1 diabetes mellitus

Background: Diabetes mellitus is a major risk factor for cardiovascular disease and is associated with a proinflammatory and prothrombotic state. We investigated whether CD40 ligand (L) expression and platelet–monocyte aggregation are increased in patients with type 1 diabetes. Methods: Serum C-reactive protein (CRP) and soluble (s) CD40L concentrations, platelet surface CD40L expression and platelet–monocyte aggregates were measured in 22 patients with uncomplicated type 1 diabetes and 22 age- and sex-matched non-diabetic control subjects. Results: In comparison to controls, patients with type 1 diabetes had higher serum CRP concentrations (3.29 ± 0.9 mg/L versus 0.99 ± 0.2 mg/L, P = 0.01), serum sCD40L concentrations (10.0 ± 1.4 ng/mL versus 4.6 ± 0.6 ng/mL, P = 0.006), and platelet surface expression of CD40L (13.8 ± 0.9% versus 8.5 ± 1.1%, P < 0.001). Platelet–monocyte aggregates were also significantly elevated in type 1 diabetes (35.9 ± 3.3% versus 26.4 ± 2.9%, P = 0.005; n = 10). We also observed a significant correlation between plasma glucose and serum CRP ( r = 0.53, P = 0.01) as well as platelet–monocyte aggregates ( r = 0.69, P = 0.03). Conclusions: Type 1 diabetes is associated with increased CD40L expression and platelet–monocyte aggregation, which may contribute to the proinflammatory and prothrombotic state as well as the accelerated atherogenesis associated with this disorder.

Characterization and application of two novel monoclonal antibodies against CD40L: epitope and functional studies on cell membrane CD40L and studies on the origin of soluble serum CD40L.

CD40 ligand, a 33-kDa cell membrane molecule, a member of the tumor necrosis factor superfamily, is an important costimulatory molecule during immune response. Here, we report on two functional mouse anti-human CD40L monoclonal antibodies 1B1 and 4F1 characterized by flow cytometry, Western blotting, and competition assay. The antibodies bound to distinct CD40L epitopes and therefore resulted in different bioactivity. Both antibodies could induce CD4+ T-cell alloantigenic hyporesponsiveness ex vivo. The antibodies were matched to develop a two-site enzyme-linked immunosorbent assay (ELISA) for soluble CD40L (sCD40L). Using this ELISA assay, we found major differences between plasma and serum sCD40L levels. Because the count of platelet sharply decreased in aplastic anemia (AA) and idiopathic thrombocytopenic purpura (ITP), we further analyzed the sCD40L concentration in the plasma of AA and ITP patients. The results showed that the sCD40L in serum was much lower than that of healthy subjects. These data demonstrate that platelets seem to be a major contributor to sCD40L, though not the only source of sCD40L in serum.

Fetal bradycardia following intrauterine platelet transfusion: might elevated levels of donor soluble CD40 ligand play a role?

Fetal bradycardia following intrauterine platelet transfusion: might elevated levels of donor soluble CD40 ligand play a role?