Prominent involvement of activated Th1-subset of T-cells and increased expression of receptor for IFN-gamma on keratinocytes in atopic dermatitis acute skin lesions

BACKGROUND: Atopic dermatitis (AD) is an allergic skin disease mediated by antigen-specific IgE and an important role has been ascribed to CD4+ cells (Th cells). The objective of the study was to evaluate humoral and cellular immunological factors in the blood and the skin lesions of AD patients, and to analyze the presence of inflammatory cell-surface markers in blood and skin biopsies. METHODS: The parameters for monitoring of 40 AD patients included results of prick test to inhalant allergens and epicutaneous (patch) test to contact allergens; values of total IgE, serum immunoglobulins (IgG, IgA, IgM) and different cell markers in the sera (CD3, CD4, CD8, CD20, CD21, CD23, HLA-DR). We also analyzed the presence of inflammatory cell-surface markers (CD3, CD4, CD8, CD20, CD20, CD1a, CD23, CD29, CD45Ro, IFNgamma+ markers) in the biopsies of skin lesions from 10 AD patients and 5 healthy controls (HCs) by immunohistochemical analysis (method of avidin-biotin immunoperoxidase). RESULTS: Beside increased total serum IgE and positive skin tests, a significantly higher percentage of CD23+ cells with lower percentage of CD21+ cells was revealed in peripheral blood of AD patients in comparison to HCs. A positive epidermal expression of the majority of markers of T cells (CD3+, CD4+, CD8+, CD29+, CD45Ro+, IFNgamma+) and those of Langerhans' cells (LCs) (CD1a, CD23+), without those of B cells (CD20+) were noted in AD patients, but no in the skin of HCs. Furthermore, significant difference was also found between the two groups for increased expression of CD3, CD4, CD8, CD29, CD45Ro, IFNgamma+ markers (markers for IFNgamma receptor) and higher intraepidermal CD23+ LCs and intradermal CD1a+ LCs in AD skin lesions. CONCLUSIONS:The obtained results suggest involvement of various humoral factors with increased production of IgE and cooperation between Th subsets and LCs, with higher production of related cytokines, and disturbed cellular immunity, including epidermal LCs with IgE receptors of high and low affinity in AD. The annotation of activated Th1 cells with increased producing of IFNgamma in acute AD skin lesions is notable, and might lead to IFNgamma binding to keratinocytes and consequently inflammatory skin changes in the disease.     

In vivo transmigrated monocytes from patients with stable coronary artery disease have a reduced expression of CD11b

Coronary artery disease (CAD) is characterized by infiltration of monocyte derived cells in the intima of the vessel wall. We hypothesized that accumulation of these cells is caused partly by an altered monocyte transmigration process in CAD. To gain insight into this issue we applied the skin blister method that allows collection of in vivo transmigrated cells at sites of local inflammation. Nineteen patients with stable CAD and 19 matched controls were enrolled. Markers of inflammation and gradients of chemokines, as well as adhesion molecule expression and up-regulation capacity, were studied. The expression of inflammatory markers, such as C-reactive protein, interleukin (IL)-6, tumour necrosis factor-alpha and IL-10, was similar in patients and controls, indicating that patients were in a stable phase of the disease. Expression of adhesion molecules, CD11b and very late activation antigen-4, on peripheral monocytes did not differ between patients and controls. However, following in vivo transmigration, monocytes in patients with CAD had a significantly reduced expression and mobilization of CD11b. The effect on CD11b could not be reproduced by in vitro stimulation with blister fluid, representing a local inflammatory milieu, or in an in vitro system of transmigration. These findings point towards differences in monocyte CD11b expression and availability at an inflammatory site between patients with CAD and healthy controls.     

Spontaneous and induced chromosome damage in somatic cells of sporadic and familial Alzheimer's disease patients.

Alzheimer's disease (AD) is a neurodegenerative disorder of the elderly with a complex etiology due to the interaction between genetic and environmental factors. At least 15% of cases are inherited as an autosomal dominant mutation, but the majority are sporadic. We evaluated cytogenetic alterations, both spontaneous and chemical-induced [aluminium (Al) and griseofulvin (GF)], by means of the micronucleus (MN) test in lymphocytes or skin fibroblasts of 14 patients with sporadic and eight with familial Alzheimer's disease (FAD), respectively. The spontaneous MN frequencies of sporadic (20.8 +/- 9.2) and familial (20.7 +/- 4.6) AD patients are significantly higher than those of the respective control groups (9.0 +/- 6.8 and 6.7 +/- 3.4). In all AD patients, GF significantly increased the spontaneous MN frequency of somatic cells to a lesser extent (P < 0.05) as compared with the control group. Al treatment did not induce MN in AD patients. The results of the present study indicate that different types of somatic cells from sporadic and familial AD patients show comparable levels of spontaneous cytogenetic anomalies, and MN induction is partially reduced or lacking according to the type of chemical treatments.     

Study of eosinophil-endothelial adhesion, production of oxygen radicals and release of eosinophil cationic protein by peripheral blood eosinophils of patients with rheumatoid arthritis

Beside lymphocytes and neutrophils, eosinophils are also involved in the inflammatory reaction in rheumatoid arthritis (RA). In this study, adhesion characteristics of peripheral blood eosinophils were studied in 43 RA patients and 19 controls, together with the expression of the beta2-integrin Mac-1 (CD11b/CD18). In addition, the production of oxygen radicals of isolated peripheral blood eosinophils and serum levels of eosinophil cationic protein (ECP) were measured in order to evaluate eosinophil activation. Adhesion of eosinophils to unstimulated human vascular endothelium was significantly higher in RA patients with active disease (n = 4) compared with controls (n = 14) (P < 0.005) and compared with patients with less active RA (n = 16) (P < 0.05). Nevertheless, the expression of the adhesion molecule Mac-1 (CD11b/CD18) was not increased in RA patients. ECP levels were higher in RA patients with active disease (P < 0.01). Release of oxygen radicals in response to phorbol stimulation was significantly elevated in active RA compared with controls (P < 0.05) and to less active RA (P < 0.05). We conclude that eosinophils of RA patients, especially those with active disease, are activated or at least primed and are involved in the inflammatory process in RA, analogous to the inflammation in asthma. The higher adhesion to inflamed endothelium is indicative of a higher infiltration in the joints, where tissue damage can be caused by toxic oxygen radicals and by granular proteins, such as ECP.     

Expressions of selected adhesion molecules on peripheral blood leukocytes in patients with aggressive periodontitis

INTRODUCTION: Aggressive forms of periodontitis lead to rapid bone destruction resulting in extensive losses in children's and young adults' dentition. Adhesion molecule deficiency syndrome and abnormalities in the expression of various adhesion molecules on peripheral blood leukocytes can be observed in prepubertal and aggressive periodontitis (AP) patients. The aim of the study was thus to assess the expression of selected cell adhesion molecules (CAMs; CD11a, CD11b, CD11c, CD54, and CD62L) on monocytes, neutrophils, and lymphocytes of the peripheral blood in patients with AP. MATERIAL/METHODS: The study involved 16 patients with AP and a control group of 13 generally healthy subjects with healthy periodontium. CAM expressions were determined by flow cytometry and presented as mean fluorescence intensity (MFI) and percentage of cells showing expression of the assessed adhesion molecules. RESULTS: Neutrophil CAM expressions in AP patients were comparable with those of the control group. MFI of CD62L on monocytes in AP patients was significantly lower than that of the controls. Lymphocytes showed increased CD11b expression compared with the control group. The percentage of leukocytes showing CAM expression in both groups was similar. Only the percentage of lymphocytes with CD11b in AP patients was significantly higher than in healthy controls. CONCLUSIONS: Because of the evident lack of differences between patients and controls and the great amount of individual dispersion of the results, the above CAMs on peripheral blood leukocytes in generally healthy patients with AP do not seem to be characteristic markers of this disease.     

Increased expression of surface activation markers on neutrophils following migration into the nasal lumen

BACKGROUND : The sequence of events following the recruitment of a free-flowing neutrophil in the peripheral circulation, via adhesion, migration and release of mediators, to a neutrophil on the surface of the nasal epithelium is a co-ordinated process. Little is known about the state of neutrophil activation following this course of events. OBJECTIVES : To investigate the expression of surface activation markers on neutrophils, reflecting activation during their recruitment to the nose, and to see whether the inflammatory process during allergic rhinitis influences this process. METHOD : Nine healthy controls and 12 patients with grass pollen-induced intermittent allergic rhinitis were investigated during the peak of the pollen season. The expression of CD11b, CD66b and CD63 on the neutrophil cell surface, as a reflection of activation, was analysed using flow cytometry. Neutrophils were derived from peripheral blood and nasal lavage fluid. In addition, eosinophil cationic protein (ECP) and myeloperoxidase (MPO) as well as L-, P- and E-selectins in the nasal lavage fluid were analysed using RIA and ELISA, respectively. RESULTS : A marked increase in the expression of all three CD markers on the neutrophil cell surface was noticed following migration from the bloodstream to the surface of the nasal mucosa. At the peak of the grass pollen season, the MPO levels increased, reflecting an increase in the total number of nasal fluid neutrophils. In parallel, the expression of CD11b was further augmented. The expression of the CDb11b was reduced on neutrophils remaining in the circulation. In addition, the level of L-selectin was reduced on neutrophils derived from the blood during allergic inflammation. CONCLUSION : Neutrophils might become activated during their transfer from the blood to the surface of the nasal mucosa, but these changes may also be due to depletion of activated neutrophils in the blood via activated endothelial/epithelial adhesion and chemoattractant measures. The increased expression of surface activation markers during allergic rhinitis suggests roles for neutrophils in the inflammatory process.     

Effect of cardiopulmonary bypass on neutrophil activity in pediatric open-heart surgery

INTRODUCTION: The nature of the participation of neutrophils in the post-cardiopulmonary bypass (CPB) inflammatory response is not very clear. The aim of our study was to investigate alterations in neutrophil phagocytic activity and adhesion molecule expression on these cells in children during and after CPB. MATERIAL/METHODS: Twenty-one children aged 6-33 months with congenital heart disease, scheduled for pri mary corrective surgery, were enrolled. The expressions of CD11b adhesion molecules and Fc? receptor on neutrophils and their phagocytic activity were evaluated. The studied markers were sequentially measured before, at the initiation of, and after CPB. RESULTS: During the course of the operation, CD11b molecule expression on neutrophils showed a slight elevation at the start of CPB (876.5+/-104.8 mean fluorescence intensity, MFI, vs. 768.1+/-178.2; p = 0.0047), followed by a significant decrease to 689.01+/-166.7 MFI after completion of the procedure. The expression of CD11b molecule on neutrophils measured at the end of CPB inversely correlated with the duration of CPB (r = -0.68, p = 0.00059). The expression of CD16 antigen dropped significantly at the start of CPB (1164.6+/-307.3 MFI vs. 1327.4+/-345.3 MFI; p = 0.0007) and remained decreased until the end of CPB (814.0+/-198.1 MFI). CONCLUSIONS: These findings suggest that the characteristics of the neutrophil response to cardiac surgery appear to depend on many factors. We demonstrated a link between the duration of CPB and adhesion molecule expression on neutrophils.     

Neutrophil CD64 Expression in Inflammatory Autoimmune Diseases: Its Value in Distinguishing Infection from Disease Flare

The purpose of this research was to clarify the significance of neutrophil CD64 expression in discrimination between infection and disease flare in patients with inflammatory autoimmune diseases. The study included 63 subjects, 20 healthy controls and 43 patients with inflammatory autoimmune diseases (24 with rheumatoid arthritis & 19 with systemic lupus erythematosus). The FC gamma receptor I (CD64 expression) on neutrophils was measured using flow cytometry. The intensity of CD64 expression on neutrophils was significantly elevated in patients with infections; 49.0 (13–205), and active autoimmune disease; 36.15 (12–133) compared to healthy controls; 5.35 (2.6–14) or patients with inactive disease; 7.5 (3.3–18). In the infectious disease group, expression of CD64 was significantly higher than in the active inflammatory disease group, while there was no significant difference between the group of patients with inactive inflammatory disease and healthy controls (P > 0.05). The sensitivity of CD64 bearing neutrophil intensity for detection of infection (using a cut off value of ≥43.5) was 94.4% and specificity was 88.9%. Neutrophil CD64 expression has a good sensitivity and specificity in differentiating infection from disease flare in patients with inflammatory autoimmune diseases. This assay could facilitate early and accurate diagnosis and greatly aid timely institution of appropriate treatment.     

Neutrophil activation in sickle cell disease.

Vascular occlusion is the main cause of the morbidity and mortality observed in patients with sickle cell disease (SCD). Increasing evidence indicates that (activated) neutrophils could play an important role in the initiation and propagation of vaso-occlusive processes in SCD. In this study, the activation state of neutrophils in sickle cell patients was analyzed by determining the level of expression of neutrophil antigens such as CD62L, CD11b, CD66b, CD63, and Fcgamma receptors. We also analyzed plasma levels of lactoferrin, elastase, soluble (s)CD16 (sFcgammaRIII), and serum levels of soluble (s)CD62L (sL-selectin) as neutrophil activation markers in these patients. Significant differences were observed in the activation state of neutrophils in non-symptomatic sickle cell patients compared to healthy HbAA controls as exemplified by significant decrease in L-selectin expression, enhanced expression of CD64, and increased levels of soluble markers like sL-selectin, elastase, and sCD16. During vaso-occlusive crisis the differences were even more pronounced. These results show neutrophils to be activated in sickle cell patients, suggesting a role of importance in the pathophysiology of sickle cell disease.     

Synovial PMN show a coordinated up-regulation of CD66 molecules.

Changes in the expression of various activation-dependent surface markers have been reported for polymorphonuclear neutrophils (PMN) isolated from synovial fluid of patients with inflammatory joint diseases. We extend these findings to the expression of CD66 molecules and several other surface markers. Three members of the CD66 family, namely CD66a, CD66b, and CD66c, showed an up to fourfold up-regulation on synovial fluid PMN compared with peripheral blood PMN (PBG) of the same patients; CD59 was increased twofold, the expression of CD16 did not change, whereas CD62L was reduced by more than 50% on synovial fluid PMN. It is interesting that CD66a, CD66b, and CD66c showed a coordinated expression on PBG of patients and controls and a coordinated up-regulation on synovial neutrophils. In contrast, after in vitro stimulation of peripheral blood PMN with phorbol myristate acetate, CD66c was much less up-regulated compared with CD66a and CD66b. All samples of synovial fluid PMN exhibited an additional increase in the expression of CD66a, CD66b, and CD66c when stimulated with phorbol myristate acetate in vitro. Prostaglandins are known to inhibit various responses of neutrophils to inflammatory stimuli. We could show that prostaglandins inhibit N-formyl-methionyl-leucyl-phenylalanine-induced up-regulation of CD66 on peripheral blood PMN in a concentration-dependent manner.     

IL-8 from local subcutaneous wounds regulates CD11b activation

The cellular and soluble mediators of a dermal inflammation can be studied by the skin chamber technique. The aim of this study was to address the physiological effect of soluble mediators, released into the skin chamber, with special focus on neutrophil CD11b activation. Mediators released at the inflammatory site were studied by Milliplex and enzyme-linked immunosorbent assay (ELISA) and correlated with transmigration and CD11b activation in vivo and in vitro. Transmigration was studied by the skin chamber technique and by the transwell method, and expression of the CBRM1/5 epitope on activated CD11b was analysed by flow cytometry following in vivo and in vitro incubation with chamber fluid or recombinant interleukin-8 (IL-8). Leucocyte in vivo and in vitro transmigration both correlated with the concentrations of IL-1β, tumour necrosis factor alpha (TNFα) and IL-8 at P < 0.05 (R > 0.7). Furthermore, CD11b was activated, in terms of exposure of the activation epitope, on neutrophils after 30 min of in vitro incubation with chamber fluid and correlated solely with the concentration of IL-8, P < 0.05 (R = 0.72). In vitro incubation with recombinant IL-8 confirmed a concentration-dependent expression of the activation epitope; however, induction of CBRM1/5 by recombinant IL-8 required a concentration that was significantly higher compared with that in chamber fluid. In addition, the CBRM1/5 epitope was analysed on in vivo extravasated neutrophils that displayed a significantly higher expression compared with circulating neutrophils, P = 0.04. We conclude that IL-8 is the major factor regulating the expression of CD11b activation epitope in neutrophils.     

Increased CD11b expression on polymorphonuclear leucocytes and cytokine profiles in patients with Kawasaki disease

Clinical evidence implicates polymorphonuclear leucocytes in the pathogenesis of vasculitis in Kawasaki disease. We examined modulation of expression of adhesion molecules (CD11b and CD62L) on polymorphonuclear leucocytes and how this expression is related to serum cytokine concentrations. In 18 patients with Kawasaki disease and 15 control subjects, adhesion molecule expression was determined by two-colour immunofluorescence staining of blood leucocytes and flow cytometry. Eight cytokines and chemokines were also measured. In patients with Kawasaki disease, mean fluorescence intensity for CD11b before giving intravenous immunoglobulin was significantly higher than in normal subjects (P<0 x 005). After intravenous immunoglobulin, mean fluorescence intensity for CD11b decreased significantly. With coronary artery lesions present, mean CD11b fluorescence intensity was significantly higher than without coronary artery lesions (P=0 x 005 before intravenous immunoglobulin; P=0 x 024 after intravenous immunoglobulin). No differences were seen in CD62L expression on polymorphonuclear leucocytes between patients with Kawasaki disease and normal subjects. CD11b expression on polymorphonuclear leucocytes correlated positively with serum interleukin (IL)-6, IL-10, granulocyte colony-stimulating factor, percentage of neutrophils among white cells and C-reactive protein. Polymorphonuclear leucocytes from patients with Kawasaki disease showed increased CD11b expression, which was associated with increased serum cytokines and appeared to be related to coronary artery lesions.     

Systemic eosinophil response induced by respiratory syncytial virus

Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract disease (LRTD) in infants. Eosinophils have been suggested to play a role in the disease pathogenesis of LRTD. Inflammation can induce functional and morphological alterations of peripheral blood granulocytes. In patients with RSV LRTD, we aimed to investigate the eosinophil activation status by analysing surface markers. In vitro stimulation of eosinophils with cytokines leads to up-regulation of CD11b and priming markers recognized by the recently developed priming markers A17 and A27, whereas interleukin (IL)-5Ralpha is being down-regulated. In 51 patients and 10 controls we examined the expression of these surface markers on eosinophils in moderate to severe RSV-induced LRTD patients at the time of admission and 6 weeks later during the convalescence phase. RSV-patients were characterized by a higher eosinophil CD11b expression compared to controls. Although basal A17 and A27 expression was not increased, we observed a significantly higher expression of these priming epitopes on N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated cells of RSV patients compared with cells of controls, indicative of prior in vivo priming. Furthermore, IL-5Ralpha expression was down-regulated on peripheral blood eosinophils of these patients. Follow-up blood samples showed normalization of all markers but CD11b, which was persistently increased. Utilizing cellular markers, we observed that peripheral blood eosinophils from infants with RSV LRTD are in a more activated state compared to eosinophils of controls, which normalizes only partially during convalescence.     

The study of immunological markers in patients with "intrinsic" type atopic dermatitis]

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by several clinical, immunological and biochemical alterations. Comparing the patients with the 'extrinsic' and 'intrinsic' types of AD, we investigated the role of immunological mechanisms in the pathogenesis of AD. To confirm it, we calculated serum markers of T lymphocyte activation: soluble interleukin-2 receptor (sIL-2R), interleukin-4 (IL-4), interleukin-10 (IL-10) and interferon-gamma (IFN-gamma). The soluble CD14 (sCD14) and tumor necrosis factor-alpha (TNF-alpha) in serum were measured as monocyte/macrophage activation markers. We examined 29 patients with the 'extrinsic' type AD (serum IgE > 10000 IU/ml: High-AD), 23 patients with the 'intrinsic' type AD (serum IgE < 37 IU/ml: Low-AD) and 11 healthy controls. Serum sIL-2R levels were increased in High-AD and Low-AD compared with the controls. They were also significantly increased in High-AD compared with Low-AD. Serum sCD14 levels were increased in High-AD compared with Low-AD and the controls. Severity index of AD were correlated with serum sIL-2R levels but not with sCD14 levels in sera. In conclusion, IgE may not relate with the pathogenesis of atopic dermatitis. Serum sIL-2R levels may be increased according to inflammatory skin lesions and it may be exaggerated with the immunological activation in the patients with the 'extrinsic' type AD.     

Expression of CD35 (CR1) and CD11b (CR3) on circulating neutrophils and eosinophils from allergic asthmatic children

Complement receptors on neutrophils and eosinophils play a role in activation and adhesion. During asthmatic reactions these receptors have been found elevated on circulating granulocytes. In the present study we compared the expression of CD35 (complement receptor type 1) and CD11b (complement receptor type 3) on neutrophils and eosinophils from asthmatic and non-asthmatic children. This was done in whole blood samples using depolarized light scattering for the discrimination of neutrophils and eosinophils. The non-stimulated expression as well as the upregulated expression of receptors by the chemotactic peptide N-formylmethionyl-leucyl-phenyl-alanine (fMLP) were studied. The results showed that without prior stimulation only the expression of CD35 on neutrophils was significantly elevated in children with asthma (P<0.05). After up-regulation with fMLP, the CD11b expression on neutrophils (P<0.005, fMLP: 0.002 microM) and eosinophils (P<0.05, fMLP: 0.02 microM) was significantly higher in asthmatic children than in the controls. These results indicate that the inducible expression of CD11b on neutrophils and eosinophils from allergic asthmatic children is primed in vivo.     

Enhanced Expression of Integrins and CD66b on Peripheral Blood Neutrophils and Eosinophils in Patients with Rheumatoid Arthritis, and the Effect of Glucocorticoids

The aim of this study was to elucidate signs of granulocyte activation by studying adhesion and phagocytosis receptors on peripheral blood granulocytes from patients with rheumatoid arthritis (RA), and to observe the effect of glucocorticoids. Analyses by flow cytometry showed elevation of the neutrophil and eosinophil expression of the alpha- and beta-chains of the beta2-integrin Mac-1 (CD11b/CD18) and of the CEA-gene family member 6 (CGM6, CD66b). Expression of the adhesion receptor antigens CD11a, CD29, CD49d, CD49f and CD44, and the Fcgamma receptors II and III, was unaffected. Treatment with low-dose prednisolone reduced the expression of CD11b on neutrophils and of CD11b, CD18 and CD66b on eosinophils to the same level as that found in healthy controls. Metyrapone treatment increased the surface expression of CD35 and CD49f on eosinophils, but did not affect surface expression on neutrophils. Activation of blood granulocytes may be important for the increased recruitment of neutrophils and eosinophils to the synovial cavity in RA. Treatment with low doses of glucocorticoids in RA normalizes the enhanced expression of the studied adhesion molecules in eosinophils but has minor impact on neutrophil activation. Endogenous glucocorticoid production seems to have minimal or no effect on the expression of adhesion and phagocytosis receptors on circulating granulocytes.     

Abnormalities in Alzheimer’s Disease Fibroblasts Bearing the APP670/671 Mutation

Abnormalities in cultured fibroblasts from familial Alzheimer’s Disease (FAD) cases uniquely enable the determination of how gene defects alter cell biology in living tissue from affected individuals. The current study focused on measures of calcium regulation and oxidative metabolism in fibroblast lines from controls and FAD individuals with the Swedish APP670/671 mutation. Bombesin-induced elevations in calcium in APP670/671 mutation-bearing lines were reduced by 40% (p < 0.05), a striking contrast to the 100% increase seen in sporadic AD and presenilin-1 (PS1) mutation-bearing cells in previously published studies. The APP670/671 mutation-bearing lines did not exhibit the exaggerated 4-bromo-A23187 releasable pool of calcium following 10 nM bradykinin, the enhanced sensitivity of calcium stores to low concentrations of bradykinin, nor the reduced activity of α-ketoglutarate dehydrogenase previously reported in cells from sporadic AD and mutant PS1 FAD. Thus, an altered regulation of internal calcium stores is common to all AD lines, but the calcium pool affected and the polarity of the alteration varies, apparently in association with particular gene mutations. Comparison of signal transduction in cell lines from multiple, genetically characterized AD families will allow testing of the hypothesis that these various pathogenic FAD abnormalities that lead to AD converge at the level of abnormal signal transduction.     

Different expression of adhesion molecules and tetraspanins of monocytes of patients with atopic eczema

BACKGROUND: Atopic eczema (AE) and psoriasis vulgaris (Pso) represent the most frequent chronic inflammatory skin diseases, which have a high number of characteristics in common but differ in their clinical picture and immunological background. A shared feature of both AE and Pso is a high recruitment of distinct proinflammatory cells from the blood into the skin at the initiation of the disease. A multistep adhesion cascade via different adhesion receptors consisting of 'tethering' and 'rolling' mediated by selectins, alpha-integrins and beta-integrins and the 'arrest' of the cells is initiated during this process. AIMS OF THE STUDY: To evaluate the expression of adhesion molecules and tetraspanins of monocytes of patients with AE and Pso in comparison with healthy controls. METHODS: We analysed the expression of adhesion molecules and tetraspanins on monocytes freshly isolated from the peripheral blood of patients with AE (n = 40) and Pso (n = 65) during exacerbation of their disease in comparison with healthy, non-atopic controls (n = 50). RESULTS: A high number of similarities between monocytes of patients with AE and patients with Pso, and disease-related differences in the expression of CD62L, CD62P, CD11a, CD11b, CD11c, CD49b, CD49d, CD49e and CD18 and the tetraspanins CD9, CD53, CD63 and CD151, which were elevated on monocytes of patients with AE could be observed. CONCLUSION: A distinct expression pattern of adhesion molecules and tetraspanins on monocytes of patients with AE and Pso might influence the recruitment process of inflammatory precursor cells and facilitate new approaches for therapeutic strategies aimed at interrupting the very earliest steps of the fateful recruitment process.     

Neutrophil expression of tumour necrosis factor receptors (TNF-R) and of activation markers (CD11b, CD43, CD63) in rheumatoid arthritis.

In vitro analysis of polymorphonuclear neutrophils (PMN) has allowed various stages of cell activation to be distinguished, characterized by the expression level of specific membrane markers and of functional receptors. Among those, TNF-alpha receptors (TNF-R) are modulated by various PMN activators, a mechanism which may be important to control cell responses to TNF in inflammatory reactions such as rheumatoid arthritis (RA). PMN, isolated from the blood of 36 RA patients and from the synovial fluid of 23 of them, were analysed for membrane expression of the two TNF-R (p55 and p75). Soluble p55 and p75 (sTNF-R) and TNF concentrations were measured in the plasma and synovial fluid by specific ELISA assays. Our results show that PMN from the blood of RA patients bear a normal number of TNF-R, with a normal p55/p75 ratio, compared with PMN from normal controls. Soluble TNF-R levels were similar in patients and normal plasma. In spite of high endogenous TNF concentration, patients' circulating PMN were not activated, as shown by a CD11b/CD18 expression similar to that of control resting cells. In contrast with blood neutrophils, PMN from RA patients' synovial fluids had an activated phenotype, characterized by increased expression of CD11b, decreased expression of leukosialin, CD43, and the appearance on the plasma membrane of an azurophil granule protein, CD63. High levels of soluble TNF-R were measured in RA synovial fluids. Nevertheless, membrane TNF-R levels and p55 and p75 proportions were similar to those of PMN from normal blood. These results suggest the existence of regulatory mechanisms which maintain a stable neutrophil expression of TNF-R as well as a balance between both types of receptors in inflammatory situations where neutrophils are strongly activated.     

Adrenomedullin Suppresses fMLP-Induced Upregulation of CD11b of Human Neutrophils

In this study we investigated the effect of adrenomedullin (AM) on fMLP-mediated activation of human neutrophils. AM partially, but significantly, suppressed fMLP-induced upregulation of CD11b expression. The inhibitory effects of AM upon fMLP-induced upregulation of CD11b expression were completely blocked by CGRP [8–37], a CGRP receptor antagonist. AM significantly increased cAMP content in neutrophils and SQ-22,536, an adenylate cyclase inhibitor, and KT-5720, a PKA inhibitor, significantly blocked the inhibitory effects of AM upon fMLP-induced upregulation of CD11b expression. This study indicates that binding of AM to the CGRP receptor suppresses fMLP-induced upregulation of CD11b expression of human neutrophils by increasing intracellular cAMP levels. AM may play an important role in the regulation of inflammatory processes, especially in the binding of neutrophils to vascular endothelial cells and subsequent neutrophil emigration evident in acute pulmonary inflammation.