Adhesion molecules and atherogenesis

Atherosclerosis is an inflammatory disease of the vessel wall characterized by monocyte infiltration in response to pro‐atherogenic factors such as oxidized lipids. Recently, the role of specific adhesion molecules in this process has been explored. The endothelium overlying atherosclerotic lesions expresses P‐selectin and the shoulder regions express vascular cell adhesion molecule‐1 (VCAM‐1) and intercellular adhesion molecule‐1 (ICAM‐1), which is also expressed on endothelium in regions not prone to plaque development. Serum levels of soluble P‐selectin, ICAM‐1 and VCAM‐1 are elevated in patients with angina pectoris or peripheral atherosclerotic disease. Reconstituted in vitro systems using monocytes on cytokine‐activated endothelial cells under shear flow suggested the involvement of P‐selectin, L‐selectin, VCAM‐1, its ligand, VLA‐4 integrin and CD18 integrins. Studies of monocyte adhesion in isolated perfused carotid arteries harvested from atherosclerotic (apoE?/?) mice show a predominant involvement of P‐selectin and its ligand P‐selectin glycoprotein‐1 (PSGL‐1) in rolling and of VLA‐4 and VCAM‐1 in firm adhesion. Consistent with these findings, apoE?/? mice that are also deficient for P‐selectin show significantly reduced atherosclerotic lesion sizes and are almost completely protected from neointimal growth after vascular injury. Milder effects are also seen in the low‐density lipoprotein (LDL) receptor deficient (LDLR?/?) mouse. In a high cholesterol/cholate model, a role of ICAM‐1 and CD18 integrins was also shown, but this awaits confirmation in more physiologic models. Transient blockade of the VLA‐4/VCAM‐1 adhesion pathway by antibodies or peptides in apoE?/? or LDLR?/? mice reduced monocyte and lipid accumulation in lesions. These data suggest that P‐selectin, PSGL‐1, VLA‐4 and VCAM‐1 are the most important adhesion molecules involved in monocyte recruitment to atherosclerotic lesions.     

Monocyte and lymphocyte surface molecules in severe sepsis and non‐septic critically ill Patients

The aim of the present study was to investigate whether expression of monocyte and lymphocyte surface molecules differs between patients with severe sepsis and non‐septic patients treated in the intensive care unit (ICU). The expression of monocyte CD14, CD40, CD80 and HLA‐DR, and lymphocyte CD69 were analyzed using quantitative flow cytometry on three consecutive days in 27 patients with severe sepsis and in 15 non‐septic patients. Receiver operating characteristic analyses were performed and each corresponding area under the curve (AUC) was determined. The results showed that the expression levels of CD40 on monocytes and CD69 on CD4+ T cells and on natural killer (NK) cells were highest in patients with severe sepsis (p < 0.05). Monocyte CD40 and NK cell CD69 expression levels were higher in patients with severe sepsis and positive blood culture compared with those with negative blood culture (p < 0.05). The highest values of AUC for severe sepsis detection were 0.836 for CD40, 0.872 for CD69 on NK cells, and 0.795 for CD69 on CD4+ T cells. These findings suggest that monocyte CD40 and CD69 on NK cells and CD4+ T cells could prove useful for new approaches in the identification of severe sepsis in the ICU.     

Circulating ICAM‐1, VCAM‐1, E‐Selectin,P‐Selectin,and TNFαRII in Patients with Coronary Artery Disease

Objective: To evaluate the relationship between the serum concentration of TNFαRII and some adhesion molecules (including ICAM‐1, VCAM‐1, P‐selectin and E‐selectin) and coronary artery stenosis. Design and setting: Observational (cross‐sectional) study in a university heart hospital in Tehran, Iran. Patients: 81 patients with angiographically proven coronary artery disease were compared with 75 individuals who had undergone coronary angiography with no significant evidence of stenosis (control subjects). Methods: Soluble adhesion molecules and TNFαRII were determined by enzyme‐linked immunosorbent assay technique. sICAM‐1 and sP‐selectin values were significantly higher in patients with coronary artery disease than in control subjects (146 ± 38 vs. 132 ± 48 p < 0.04 and 275 ± 107 vs. 241 ± 104 ng/ml p < 0.04 respectively). Multiple logistic regression analysis showed sICAM‐1 as an independent discriminating risk factor for coronary artery disease (p < 0.03). Prediction models that incorporated sICAM‐1 in addition to other established coronary risk factors were significantly better at predicting risk than the models based on the other risk factors alone. Multiple regression analysis indicated that sP‐selectin levels were greater in patients with single‐vessel disease than in the respective normal (p < 0.01). Conclusions: Our findings suggest that sICAM‐1 has an association with stable coronary artery disease and the evaluation of this marker may improve the coronary risk assessment in Iranian patients.     

Interferon-beta and adhesion molecules (E-selectin and s-intracellular adhesion molecule-1) are detected in sera from patients with retinal vasculitis and are induced in retinal vascular endothelial cells by Toll-like receptor 3 signalling

Retinal vasculitis is a major component of ocular inflammation that plays a role in retinal tissue damage in patients with idiopathic uveitis and Behçet's disease. Here we show that type 1 interferons (IFN α/β) were not detected in sera from normal individuals but were identified in up to 46% of the sera from retinal vasculitis patients. The predominant form of IFN observed was IFN‐β, which was detected in 39% of Behçet's disease patients and 47% of idiopathic uveitis patients. Seven patients whose sera contained IFN‐β were monitored prospectively. IFN‐β was shown to be present for 6–12 months in all seven of the sera samples tested. Furthermore, the adhesion molecule profile identified in this study was strikingly different when Behçet's and uveitis patient sera were compared to sera from normal controls. Sera from Behçet's disease patients contained significantly elevated levels of the soluble adhesion molecules, sE‐selectin and s‐intracellular adhesion molecule‐1 (sICAM‐1), whereas sera from patients with idiopathic uveitis contained significantly increased sE‐selectin. In vitro studies evaluating the cell source of these cytokines revealed that polyriboinosinic polyribocytidylic acid (poly I:C) activated retinal vascular endothelial cells produce sE‐selectin, sICAM‐1 and IFN‐β. Production of these molecules was inhibited by pretreatment with anti‐Toll‐like receptor 3 (TLR‐3) antibody. In conclusion, IFN‐β, sE‐selectin and sICAM‐1 are elevated in patients with retinal vasculitis and are induced in retinal vascular endothelial cells in vitro by activating the innate immune system through TLR‐3. Further analysis of innate immune signalling may prove to be a novel target for future studies on pathogenic mechanisms and therapeutic approaches in retinal vasculitis.     

Circulating ICAM‐1, VCAM‐1, E‐Selectin,P‐Selectin,and TNFRII in Patients with Coronary Artery Disease

Objective: To evaluate the relationship between the serum concentration of tumor necrosis factor receptor 2 (TNFRII) and some adhesion molecules [including intercellular adhesion molecule‐1 (ICAM‐1), vascular cell adhesion molecule‐1 (VCAM‐1), P‐Selectin, and E‐Selectin] and coronary artery stenosis. Design and setting: Observational (cross‐sectional) study in a University Heart Hospital in Tehran, Iran. Patients: 75 patients with angiographically proven coronary artery disease were compared with 81 individuals who had undergone coronary angiography with no significant evidence of stenosis (control subjects). Methods: Soluble adhesion molecules and TNFRII were determined by enzyme‐linked immunosorbent assay technique. sICAM‐1 and sP‐selectin values were significantly higher in patients with coronary artery disease than in control subjects [146(38) vs. 132(48) p < 0.04 and 275(107) vs. 241(104) ng/ml p < 0.04 respectively]. Multiple logistic regression analysis showed sICAM‐1 an independent discriminating risk factor for coronary artery disease (p < 0.03). Prediction models that incorporated sICAM‐1 in addition to other established coronary risk factors were significantly better at predicting risk than the models based on the other risk factors alone. Multiple regression analysis indicated that sP‐selectin levels were greater in patients with single‐vessel disease than in the respective normal (p < 0.01). Conclusions: Our findings suggest that sICAM‐1 has an association with s1 coronary artery disease as such; the evaluation of this marker may improve the coronary risk assessment in Iranian patients.     

Expression of NK Cell and Monocyte Receptors in Critically Ill Patients – Potential Biomarkers of Sepsis

Sepsis is characterized by activation of both the innate and adaptive immune systems as a response to infection. During sepsis, the expression of surface receptors expressed on immune competent cells, such as NKG2D and NKp30 on NK cells and TLR4 and CD14 on monocytes, is partly regulated by pro‐ and anti‐inflammatory mediators. In this observational study, we aimed to explore whether the expression of these receptors could be used as diagnostic and/or prognostic biomarkers in sepsis. Patients with severe sepsis or septic shock (n = 21) were compared with critically ill non‐septic patients (n = 15). Healthy volunteers (n = 15) served as controls. To elucidate variations over time, all patients were followed for 4 days. Cell surface expression of NKG2D, NKp30, TLR4 and CD14 and serum levels of IL‐1β, IL‐6, IFN‐γ, TNF‐α, IL‐4 and IL‐10 was estimated by flow cytometry. We found that NK cell expression of NKG2D and monocyte expression of CD14 were lower in the septic patients compared with the non‐septic patients, both at ICU admission and during the observation period (P < 0.01 for all comparisons). Both at ICU admission, and during the observation period, levels of IL‐6 and IL‐10 were higher in the septic patients compared with the non‐septic patients (P < 0.001 for all comparisons). Conclusion: As both NKG2D and CD14 levels appear to distinguish between septic and non‐septic patients, both NKG2D and CD14 may be considered potential diagnostic biomarkers of severe sepsis and septic shock.     

Maternal Levels of Prostacyclin,Thromboxane, ICAM,and VCAM in Normal and Preeclamptic Pregnancies

Citation Lewis DF., Canzoneri BJ., Gu Y, Zhao S, Wang Y. Maternal Levels of Prostacyclin, Thromboxane, ICAM, and VCAM in normal and preeclamptic pregnancies. Am J Reprod Immunol 2010; 64: 376–383 Problem To evaluate whether impaired endothelial function and endothelial inflammatory response occur in parallel in the women with preeclampsia. Method of Study Venous blood was drawn from normal (n = 40) and severe preeclamptic (sPE) (n = 40) pregnant women when they were admitted to the L&D Unit and 24 hrs after delivery. Plasma and serum samples were extracted and measured for 6‐keto PGF1α and TXB₂ (stable metabolites of PGI2 and TXA2), and intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) by ELISA. Data are analyzed by Mann–Whitney test and paired t‐test. The statistical significance is set as P < 0.05. Results Plasma 6‐keto PGF1α levels were significantly reduced at admission and 24 hr after delivery in sPE compared to normal pregnant controls, P < 0.01. The ratio of 6‐keto PGF1α and TXB₂ was significant less in sPE than that in normal pregnant controls before delivery. There was no significant difference for ICAM and VCAM levels between normal and patients with sPE before and after delivery. Conclusion Maternal 6‐keto PGF1α levels and the ratio of 6‐keto PGF1α and TXB₂ were decreased in patients with sPE compared to normal pregnant controls. In contrast, maternal ICAM and VCAM levels were not different between the two groups. These data suggest that serum ICAM and VCAM levels may not be sensitive inflammatory biomarkers for preeclampsia.     

Glatiramer acetate attenuates the pro‐migratory profile of adhesion molecules on various immune cell subsets in multiple sclerosis

An altered expression pattern of adhesion molecules (AM) on the surface of immune cells is a premise for their extravasation into the central nervous system (CNS) and the formation of acute brain lesions in multiple sclerosis (MS). We evaluated the impact of glatiramer acetate (GA) on cell‐bound and soluble AM in the peripheral blood of patients with relapsing–remitting MS (RRMS). Fifteen patients treated de novo with GA were studied on four occasions over a period of 12 months. Surface levels of intracellular cell adhesion molecule (ICAM)‐1, ICAM‐3, lymphocyte function‐associated antigen (LFA)‐1 and very late activation antigen (VLA)‐4 were assessed in T cells (CD3⁺CD8⁺, CD3⁺CD4⁺), B cells, natural killer (NK) cells, natural killer T cells (NK T) and monocytes by five‐colour flow cytometry. Soluble E‐selectin, ICAM‐1, ICAM‐3, platelet endothelial cell adhesion molecule (PECAM)‐1, P‐selectin and vascular cell adhesion molecule (VCAM)‐1 were determined with a fluorescent bead‐based immunoassay. The pro‐migratory pattern in RRMS was verified by comparison with healthy controls and was characterized by up‐regulation of LFA‐1 (CD3⁺CD4⁺ T cells, B cells), VLA‐4 (CD3⁺CD8⁺ T cells, NK cells), ICAM‐1 (B cells) and ICAM‐3 (NK cells). Effects of GA treatment were most pronounced after 6 months and included attenuated levels of LFA‐1 (CD3⁺CD4⁺) and VLA‐4 (CD3⁺CD4⁺, CD3⁺CD8⁺, NK, NK T, monocytes). Further effects included lowering of ICAM‐1 and ICAM‐3 levels in almost all immune cell subsets. Soluble AM levels in RRMS did not differ from healthy controls and remained unaltered after GA treatment. The deregulated pro‐migratory expression profile of cell‐bound AM is altered by GA treatment. While this alteration may contribute to the beneficial action of the drug, the protracted development and unselective changes indicate more secondary immune regulatory phenomena related to these effects.     

Plasma PTX3, MCP1 and Ang2 are early biomarkers to evaluate the severity of sepsis and septic shock

Sepsis is associated with significant mortality. Early diagnosis and prognosis of patients with sepsis is still a difficult clinical challenge. In this study, the ability of plasma PTX3 (pentraxin 3), MCP1 (monocyte chemoattractant protein 1) and Ang (angiopoietin)1/2 was investigated to evaluate the severity of sepsis. Blood samples were obtained from 43 patients with sepsis. A total of 33 post‐surgery patients with infections and 25 healthy individuals served as controls. The results showed that plasma PTX3, MCP1 and Ang2 significantly increased in patients on the first day of septic shock onset, while sepsis patients had significantly higher Ang2 level, compared with controls. Furthermore, PTX3, MCP1 and Ang2 had high AUROC values in patients with septic shock on the first day of sepsis onset. The findings suggest that PTX3, MCP1 and Ang2 maybe early predictors to evaluate the severity of sepsis and septic shock with the latest Sepsis 3.0 definitions.     

Altered levels of soluble CD18 may associate immune mechanisms with outcome in sepsis

The pathogenesis of sepsis involves a dual inflammatory response, with a hyperinflammatory phase followed by, or in combination with, a hypoinflammatory phase. The adhesion molecules lymphocyte function‐associated antigen (LFA‐1) (CD11a/CD18) and macrophage‐1 (Mac‐1) (CD11b/CD18) support leucocyte adhesion to intercellular adhesion molecules and phagocytosis through complement opsonization, both processes relevant to the immune response during sepsis. Here, we investigate the role of soluble (s)CD18 in sepsis with emphasis on sCD18 as a mechanistic biomarker of immune reactions and outcome of sepsis. sCD18 levels were measured in 15 septic and 15 critically ill non‐septic patients. Fifteen healthy volunteers served as controls. CD18 shedding from human mononuclear cells was increased in vitro by several proinflammatory mediators relevant in sepsis. sCD18 inhibited cell adhesion to the complement fragment iC3b, which is a ligand for CD11b/CD18, also known as Mac‐1 or complement receptor 3. Serum sCD18 levels in sepsis non‐survivors displayed two distinct peaks permitting a partitioning into two groups, namely sCD18 ‘high’ and sCD18 ‘low’, with median levels of sCD18 at 2158 mU/ml [interquartile range (IQR) 2093–2811 mU/ml] and 488 mU/ml (IQR 360–617 mU/ml), respectively, at the day of intensive care unit admission. Serum sCD18 levels partitioned sepsis non‐survivors into one group of ‘high’ sCD18 and low CRP and another group with ‘low’ sCD18 and high C‐reactive protein. Together with the mechanistic data generated in vitro, we suggest the partitioning in sCD18 to reflect a compensatory anti‐inflammatory response syndrome and hyperinflammation, respectively, manifested as part of sepsis.     

Heterogeneity among septic shock patients in a set of immunoregulatory markers

Immune activation is a regular feature of sepsis, but the incidence and nature of the ensuing inflammation-resolving and immunosuppressive component is less well understood. In this study, we compared immunoregulatory markers on blood leukocytes from patients with Gram-negative or Gram-positive sepsis or septic shock, and compared this to blood from patients with severe virosis or healthy controls. To this end, blood from 32 patients with sepsis, including ten cases with shock, and 12 patients with severe virosis were analysed by flow cytometry for the expression levels of monocyte HLA-DR, CD11c, CD14 and CD40, and for frequencies of CD163⁺-suppressive monocytes, HLA-DR⁺ or CD40⁺-activated T cells and Tregs. Plasma cytokine levels were analysed as a functional measurement. Signs of immunosuppression dominated in the septic shock and Gram-positive sepsis groups, whereas monocyte activation was common in Gram-negative sepsis patients without shock. However, the main finding was the large inter-individual variation of immune activation and immunosuppression, with no correlation to prognosis among the shock patients. The pronounced inter-individual variation in the analysed monocyte and lymphocyte markers forms a strong argument that, when immunomodulatory treatment is considered in a sepsis patient, it should be personalised and guided by a detailed immune status assessment.     

Graves病患者外周血细胞间粘附分子-1水平检测的临床价值

目的 :探讨外周血细胞间粘附分子 1(ICAM 1)水平检测在Graves病患者中的价值。方法 :用流式细胞术测定 37例Graves病 (GD)患者治疗前外周血淋巴细胞膜上细胞间粘附分子 1(CD5 4 )、CD4 、CD3 、CD8 、CD19 、CD2 5 (可溶性白介素 2受体 )的表达水平 ,用ELISA方法测定其血清中可溶性细胞间粘附分子 1(sICAM 1)的浓度 ,并测定其它体液免疫指标(TsAb、TGAb、TpoAb) ,同时和 2 2例正常对照人群进行各指标间的比较 ;Graves病患者TsAb阳性率与sICAM 1阳性率进行比较 ;此外 ,在细胞间粘附分子 1水平与机体其它免疫指标间做相关分析。结果 :Graves病患者血清可溶性细胞间粘附分子 1水平明显高于对照人群 (P <0 0 0 1) ,但与体液免疫指标间无相关关系 ,与细胞免疫指标中的CD4 水平呈负相关 (n =37,rs =- 0 4 91,P<0 0 0 5 ) ;GD病患者sICAM 1的阳性率 (89 19% )显著高于TsAb的阳性率 (6 7 5 7% ,P <0 0 5 )。结论 :sICAM 1在未治疗的GD病患中升高 ,其阳性率显著高于TsAb的阳性率 ,其升高与体液免疫指标不相关 ,与细胞免疫指标有一定关系     

Increased Expression of Programmed Cell Death‐1 in Regulatory T Cells of Patients with Severe Sepsis and Septic Shock: An Observational Clinical Study

While regulatory T cells (Tregs) constitutively express programmed cell death‐1 (PD‐1), the role of PD‐1 expression in Tregs of patients with sepsis remains unclear. Thus, we determined PD‐1 expression in Tregs from the peripheral blood of patients with severe sepsis and septic shock. Seventy‐eight patients with severe sepsis and 40 with septic shock, as well as 21 healthy subjects, were enrolled in this study. The percentage of peripheral blood PD‐1⁺ Tregs, as well as absolute Treg counts, were compared between these three groups. PD‐1 expression in Tregs and absolute Treg counts were also compared between survivors and non‐survivors in patients with sepsis. PD‐1 expression in Tregs increased in patients with sepsis compared to healthy controls. Conversely, absolute Treg counts were significantly decreased in patients with sepsis compared to healthy controls; patients with septic shock had the lowest absolute Treg counts. Among patients with sepsis, survivors had lower levels of PD‐1 expression in Tregs, as well as higher absolute Treg counts, than non‐survivors. Additionally, the percentage of PD‐1⁺ Tregs correlated positively with lactate levels as well as the Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores in patients with sepsis. PD‐1 was upregulated in Tregs of patients with sepsis and may indicate a state of immune dysfunction. Overexpression of PD‐1 in Tregs was associated with more severe sepsis as well as poor outcomes.     

Expression of CD11c and EMR2 on neutrophils: potential diagnostic biomarkers for sepsis and systemic inflammation

There is a need for cellular biomarkers to differentiate patients with sepsis from those with the non‐infectious systemic inflammatory response syndrome (SIRS). In this double‐blind study we determined whether the expression of known (CD11a/b/c, CD62L) and putative adhesion molecules [CD64, CD97 and epidermal growth factor (EGF)‐like molecule containing mucin‐like hormone receptor (EMR2)] on blood neutrophils could serve as useful biomarkers of infection and of non‐infectious SIRS in critically ill patients. We studied 103 patients with SIRS, 83 of whom had sepsis, and 50 healthy normal subjects, using flow cytometry to characterize neutrophils phenotypically in whole blood samples. Patients with SIRS had an increased prevalence of neutrophils expressing CD11c, CD64 and EMR2 in comparison with healthy subjects (P < 0·001), but normal expression of CD11a, CD11b, CD62L and CD97. An increase in the percentage of neutrophils bearing CD11c was associated with sepsis, EMR2 with SIRS and CD64 with sepsis and SIRS. Neutrophils expressing CD11c had the highest sensitivity (81%) and specificity (80%) for the detection of sepsis, and there was an association between the percentage of neutrophils expressing EMR2 and the extent of organ failure (P < 0·05). Contrary to other reports, we did not observe an abnormal expression of CD11b or CD62L on neutrophils from patients with SIRS, and suggest that this discrepancy is due to differences in cell processing protocols. We propose that blood neutrophils expressing CD11c and EMR2 be considered as potential biomarkers for sepsis and SIRS, respectively.     

Farnesyltransferase inhibitor FTI‐277 inhibits PD‐L1 expression on septic spleen lymphocytes and promotes spleen lymphocyte activation

Farnesyltransferase inhibitors have been tested in clinical trials for the treatment of tumours. In sepsis, the binding of programmed death 1 (PD‐1) to programmed death ligand 1 (PD‐L1) promotes lymphocyte apoptosis and decreases cytokine expression, thus affecting survival rates. The PD‐1/PD‐L1 pathway plays an important role in chronic viral infection, bacterial infection and sepsis. However, the precise immunosuppressive and anti‐inflammatory functions of this pathway remain poorly understood. In our previous study, the induction of sepsis by caecal ligation and puncture (CLP) resulted in increased farnesyltransferase activity and farnesylated protein levels in the spleen relative to sham treatment. However, the effect of inhibition of farnesyltransferase activity on overall survival rates in patients with sepsis and the specific signalling pathway involved remain to be investigated. In this study, mice with CLP‐induced sepsis were treated with farnesyltransferase inhibitor (FTI‐277), and PD‐L1 expression on septic spleen lymphocytes was examined. Flow cytometric analysis revealed that PD‐L1 is expressed constitutively on lymphocytes and that PD‐L1 protein expression was up‐regulated strongly following CLP. FTI‐277 down‐regulated PD‐L1 mRNA and protein expression on septic spleen lymphocytes in a dose‐dependent manner. This effect was associated closely with nuclear factor kappa B (NF‐κB). In addition, the significant damping effect of FTI‐277 on the PD‐L1 signal promoted interferon (IFN)‐γ secretion, interleukin (IL)‐2 production and splenocyte proliferation in response to anti‐CD3⁺CD28⁺ antibodies in mice. Furthermore, FTI‐277 reduced spleen lymphocyte apoptosis in septic mice. Therefore, FTI‐277 regulates spleen lymphocyte activity via the PD‐L1 signalling pathway, with significant anti‐inflammatory effects attributable to suppression of the NF‐κB pathway. Farnesyltransferase represents a valuable therapeutic target for the treatment of sepsis.     

Blockade of CD40–TRAF2,3 or CD40–TRAF6 is sufficient to inhibit pro‐inflammatory responses in non‐haematopoietic cells

Inhibition of the CD40–CD154 pathway controls inflammatory disorders. Unfortunately, administration of anti‐CD154 monoclonal antibodies causes thromboembolism. Blockade of signalling downstream of CD40 may represent an approach to treat CD40‐driven inflammatory disorders. Blocking tumour necrosis factor receptor‐associated factor 6 (TRAF6) signalling downstream of CD40 in MHC II⁺ cells diminishes inflammation. However, CD40–TRAF6 blockade may cause immunosuppression. We examined the role of CD40–TRAF2,3 and CD40–TRAF6 signalling in the development of pro‐inflammatory responses in human non‐haematopoietic and monocytic cells. Human aortic endothelial cells, aortic smooth muscle cells, renal proximal tubule epithelial cells, renal mesangial cells and monocytic cells were transduced with retroviral vectors that encode wild‐type CD40, CD40 with a mutation that prevents TRAF2,3 recruitment (ΔT2,3), TRAF6 recruitment (ΔT6) or both TRAF2,3 plus TRAF6 recruitment (ΔT2,3,6). Non‐haematopoietic cells that expressed CD40 ΔT2,3 exhibited marked inhibition in CD154‐induced up‐regulation of vascular cell adhesion molecule 1, intercellular adhesion molecule 1 (ICAM‐1), monocyte chemotactic protein 1 (MCP‐1), tissue factor and matrix metalloproteinase 9. Similar results were obtained with cells that expressed CD40 ΔT6. Although both mutations impaired ICAM‐1 up‐regulation in monocytic cells, only expression of CD40 ΔT6 reduced MCP‐1 and tissue factor up‐regulation in these cells. Treatment of endothelial and smooth muscle cells with cell‐permeable peptides that block CD40–TRAF2,3 or CD40–TRAF6 signalling impaired pro‐inflammatory responses. In contrast, while the CD40–TRAF2,3 blocking peptide did not reduce CD154‐induced dendritic cell maturation, the CD40–TRAF6 blocking peptide impaired this response. Hence, preventing CD40–TRAF2,3 or CD40–TRAF6 interaction inhibits pro‐inflammatory responses in human non‐haematopoietic cells. In contrast to inhibition of CD40–TRAF6 signalling, inhibition of CD40–TRAF2,3 signalling did not impair dendritic cell maturation. Blocking CD40–TRAF2,3 signalling may control CD40–CD154‐dependent inflammatory disorders.     

ICAM‐1 and B7‐1 provide similar but distinct costimulation for CD8+ T cells,while CD4+ T cells are poorly costimulated by ICAM‐1

The function of purified ICAM‐1 in costimulating CD4⁺ and CD8⁺ T cell responses has been directly compared to that of B7‐1 in a model system that minimizes contributions of other receptor‐ligand interactions. While B7‐1 costimulates both subsets of T cells, ICAM‐1 is much more effective in the costimulation of CD8⁺ cells. ICAM‐1 also synergizes with B7‐1 for the induction of IL‐2 production in CD8⁺ but not CD4⁺ T cells. These differences are not explained by differences in LFA‐1 receptor expression on the two subsets of T cells. The CD8⁺ T cell response to ICAM‐1 costimulation is associated with increased proliferation and IL‐2 production at levels similar to those seen with B7‐1 costimulation, but clonal expansion in response to ICAM‐1 is not as great due to decreased cell survival. ICAM‐1‐mediated costimulation is effective for both naive and memory CT8⁺ T cells, is independent of CD28 engagement, and does not appear to be due solely to effects on adhesion. These results suggest that ICAM‐1‐dependent, B7‐independent costimulation may be important in initiating a CTL response to class I antigen presented by cells that are not professional APC.     

Inflammasome gene profile is modulated in septic patients,with a greater magnitude in non‐survivors

Inflammasome signalling induces the processing and secretion of interleukin (IL)‐1β and IL‐18 which, coupled with pyroptosis, activate further the inflammatory response. In the present study we evaluated the expression of genes involved in inflammasome signalling pathways in septic patients, their interaction networks and the predicted functions modulated in survivors and non‐survivors. Twenty‐seven patients with sepsis secondary to community‐acquired pneumonia admitted to intensive care units from three general hospitals in São Paulo were included into the study. We performed a polymerase chain reaction (PCR) array encompassing 35 genes related to the nucleotide‐binding oligomerization domain and leucine‐rich repeat‐containing (NLR)‐inflammasome in peripheral blood mononuclear cells obtained at admission and after 7 days of follow‐up. Eleven healthy volunteers were used as the reference group. Increased NLRC4 and NLRP3 and decreased nucleotide‐binding oligomerization domain (NOD1), and NLRP1 expression was observed in septic patients compared to healthy individuals; the IL‐1β and IL‐18 expression levels were also high in the patients. The gene expression changes followed the same patterns in surviving and non‐surviving patients, with higher magnitudes observed in non‐survivors. Functional analyses revealed, however, that activation and inhibition intensity for representing functions were different in survivors and non‐survivors, as for production of reactive oxygen species, synthesis of nitric oxide and for the control of bacterial infections. Our results showed that the genes involved in the activation of the NLR‐inflammasome cascades were altered substantially in septic patients, with a higher number of altered genes and a higher intensity in the disturbance of gene expression found among patients dying of sepsis.     

Systemic endothelial activation occurs in both mild and severe malaria. Correlating dermal microvascular endothelial cell phenotype and soluble cell adhesion molecules with disease severity.

Fatal Plasmodium falciparum malaria is accompanied by systemic endothelial activation. To study endothelial activation directly during malaria and sepsis in vivo, the expression of cell adhesion molecules on dermal microvascular endothelium was examined in skin biopsies and correlated with plasma levels of soluble (circulating) ICAM-1, E-selectin, and VCAM-1 and the cytokine tumor necrosis factor (TNF)-alpha. Skin biopsies were obtained from 61 cases of severe malaria, 42 cases of uncomplicated malaria, 10 cases of severe systemic sepsis, and 17 uninfected controls. Systemic endothelial activation, represented by the up-regulation of inducible cell adhesion molecules (CAMs) on endothelium and increased levels of soluble CAMs (sCAMs), were seen in both severe and uncomplicated malaria and sepsis when compared with uninfected controls. Plasma levels of sICAM-1, sVCAM-1, and sE-selectin correlated positively with the severity of malaria whereas TNF-alpha was raised nonspecifically in malaria and sepsis. Immunohistochemical evidence of endothelial activation in skin biopsies did not correlate with sCAM levels or disease severity. This indicates a background of systemic endothelial activation, which occurs in both mild and severe malaria and sepsis. The levels of sCAMs in malaria are thus not an accurate reflection of endothelial cell expression of CAMs in a particular vascular bed, and other factors must influence their levels during disease.     

Downregulation of CD40 ligand response in monocytes from sepsis patients

It has been suggested that a defective adaptive immune response contributes to septic immunosuppression. Here, the response of monocytes to CD40 ligand (CD40L) for patients with sepsis due to infection with gram-negative organisms has been analyzed. Compared to cells from controls, monocytes from septic patients showed significantly reduced production of tumor necrosis factor alpha, interleukin-1β (IL-1β), and IL-12 and were unable to acquire high levels of CD80 and CD86 molecules. These alterations were observed at the onset of sepsis and persisted at day 7. However, the ability of monocytes to respond to CD40L stimulation was partially but significantly restored in cells from patients who recovered from sepsis. In addition, costimulation of autologous CD4⁺ T lymphocytes by CD40L-activated monocytes from septic patients failed to induce cell proliferation and gamma interferon production. Finally, the ability of CD40L to rescue monocytes from apoptosis was severely impaired. We conclude that downregulation of the CD40L response may be an appropriate model for the monocyte alteration observed during septic immunosuppression and may help in the development of novel therapeutic strategies.