Differential expression of monocyte CD163 in single- and dual-asthmatic responders during allergen-induced bronchoconstriction

Clinical utility of circulating TWEAK and CD163 as biomarkers of iron-induced cardiac decompensation in transfusion dependent thalassemia major

BACKGROUND AND AIM

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) affects most of the cells involved in cardiac fibrosis like inflammatory cells, cardiomyocytes and fibroblasts. CD163, the receptor of TWEAK on the surface of type 2 macrophages, is shed into plasma upon macrophages activation. This work aimed to evaluate serum TWEAK and its decoy receptor CD163 as probable biomarkers to monitor myocardial iron overload (MIO) in transfusion dependent thalassemia major (TDTM) patients and to predict iron-induced cardiac decompensation (IICD).

METHODS

A total of 140 TDTM patients were enrolled. Patients were categorized into two groups; group I (n = 70) diagnosed with IICD while group II (n = 70) had no evidence of IICD. sTWEAK and sCD163 were quantitated utilizing Enzyme-linked-immunosorbent- assay.

RESULTS

sTWEAK was evidently lower in group I than group II (medians, 412 and 1052 pg/mL respectively). sCD163 was higher in group I than group II (medians, 615.5 and 323.5 ng/mL respectively). sTWEAK positively correlated with cardiac MRI-T2 mapping and ventricular ejection fractions and negatively correlated with B-Natriuretic peptide and cardiac troponin. An inverse relationship between TWEAK and CD163 was documented throughout the study. sTWEAK, sCD163 and TWEAK/CD163 ratio proved to be significant predictors of IICD in TDTM patients. TWEAK/CD163 ratio < 1.04 discriminated IICD in TDTM patients with 100 % clinical sensitivity and specificity.

CONCLUSION

Circulating TWEAK and CD163 appears to be promising biomarkers for monitoring MIO and predicting IICD in TDTM patients.

Systemic corticosteroid therapy augments ex vivo release of sCD163 by peripheral blood monocytes of asthmatic patients

Introduction

The CD163 is exclusively expressed by mononuclear phagocytes as a transmembrane protein, which synthesis is regulated by anti- and pro-inflammatory signals. After shedding from the cell surface it exists in body fluids as a soluble protein (sCD163) which exerts anti-inflammatory effects.

Aim

To evaluate serum concentration and ex vivo production of sCD163 by peripheral blood mononuclear cells (PBMC) in asthmatic patients treated with inhaled (ICS) or oral corticosteroids (OCS).

Material and methods

The study was performed on 35 allergic asthma patients (AAs) including 15 treated with ICS (ICS-AAs), 10 with OCS (OCS-AAs), 10 during asthma exacerbation (EX-AAs) before OCS had been started and 13 non-atopic healthy subjects (HCs) as a control group. PBMC were cultured in vitro for up to 144 h. The concentration of sCD163 in serum and the culture supernatants was evaluated with ELISA.

Results

The greatest serum sCD163 concentration was demonstrated in EX-AAs, which was significantly greater than that in other studied subgroups. The concentration of sCD163 in PBMC culture supernatants was greater in AAs than in HCs (p = 0.006). Among individual asthma subgroups the greatest concentration of sCD163 was demonstrated in PBMC culture supernatants of OCS-AAs, which was significantly greater than in ICS-AAs (p < 0.001) and EX-AAs (p < 0.001), both being significantly greater than in HCs (p < 0.001).

Conclusions

In AAs, enhanced capability of PBMCs to release sCD163 may be at least partially responsible for the anti-inflammatory effects of systemic corticosteroid therapy.

Differential expression of CCR2 and CX3CR1 on CD16+ monocyte subsets is associated with asthma severity

Background

Monocytes play an important role in immune and inflammatory diseases and monocyte subsets are predictors of disease in certain conditions. Expression of the chemokine receptors, CCR2 and CX₃CR1 on monocyte subsets relates to their function and can be used in their characterization. Our objective was to determine whether CD14, CD16, CCR2 and CX₃CR1 on monocyte subsets are potential indicators of asthma severity.

Methods

Blood samples were collected from Saudi Arabian patients with asthma and normal healthy individuals. Six-color flow-cytometry phenotypic analysis was used to identify human blood monocyte subsets, based on their expression of CD14 and CD16 following CD45 gating. Expression of CCR2 and CX₃CR1 was analysed on classical (CD14⁺⁺CD16⁻), intermediate (CD14⁺⁺CD16⁺) and non-classical (CD14⁺CD16⁺⁺) subsets and correlated with disease severity.

Results

We demonstrated a significant increase in percentage of total CD45-positive monocytes in the blood of patients with severe asthma, but the proportion of the individual monocyte subsets was not significantly changed when patients with mild, moderate and severe asthma were compared with healthy individuals. CD16 expression (mean fluorescence intensity, MFI) was decreased on intermediate and non-classical subsets in patients with severe asthma compared to healthy controls. CX₃CR1 expression was also lower, with a lower percentage of cells expressing CX₃CR1 in the non-classical CD14⁺CD16⁺⁺ subset in all patients with asthma and this was inversely related to the percentage of cells expressing CCR2.

Conclusions

CCR2 expression on monocytes indicated a tendency toward more phagocytic monocytes in patients with asthma. The differential expression of CD16, CX₃CR1 and CCR2 on monocyte subsets in peripheral blood indicates modulation of the inflammatory response and suggests a role for monocytes in asthma pathogenesis.

Therapeutic Potential of Hematopoietic Prostaglandin D2 Synthase in Allergic Inflammation

Worldwide, there is a rise in the prevalence of allergic diseases, and novel efficient therapeutic approaches are still needed to alleviate disease burden. Prostaglandin D₂ (PGD₂) has emerged as a central inflammatory lipid mediator associated with increased migration, activation and survival of leukocytes in various allergy-associated disorders. In the periphery, the hematopoietic PGD synthase (hPGDS) acts downstream of the arachidonic acid/COX pathway catalysing the isomerisation of PGH₂ to PGD₂, which makes it an interesting target to treat allergic inflammation. Although much effort has been put into developing efficient hPGDS inhibitors, no compound has made it to the market yet, which indicates that more light needs to be shed on potential PGD₂ sources and targets to determine which particular condition and patient will benefit most and thereby improve therapeutic efficacy. In this review, we want to revisit current knowledge about hPGDS function, expression in allergy-associated cell types and their contribution to PGD₂ levels as well as beneficial effects of hPGDS inhibition in allergic asthma, rhinitis, atopic dermatitis, food allergy, gastrointestinal allergic disorders and anaphylaxis.

Synergistic effect of Dermatophagoides pteronyssinus allergens and dexamethasone on the expression of CD163 by peripheral blood mononuclear cells

BACKGROUND

The CD163 is a marker of monocyte/macrophage anti-inflammatory function. Its soluble form (sCD163) also exert anti-inflammatory activities including inhibition of T cell proliferation.

OBJECTIVE

To evaluate the effect of dexamethasone (Dx) and Dermatophagoides pteronyssinus (Dp) on ex vivo production of sCD163 by peripheral blood mononuclear cells (PBMCs).

METHODS

PBMCs from 26 allergic asthma patients (AAs) and 12 non-atopic healthy controls (HCs) were cultured with Dp, Dx, Dp + Dx or without any stimulation for up to 144 h (T₁₄₄). Concentration of sCD163, interleukin (IL) -6 and IL-10 in PMBC culture supernatants was evaluated using ELISA. The mRNA expression of CD163 by PBMCs was estimated using quantitative PCR (qPCR).

RESULTS

At T₁₄₄ the median concentration of CD163 in unstimulated PBMC cultures of AAs was greater than that in HCs (p = 0.008). Concomitant application of Dp and Dx resulted in a synergistic effect reflected by a dramatic increase of sCD163 concentration both in HCs (p = 0.0002) and AAs (p < 0.0001). Also a synergistic effect of Dp and Dx on CD163 mRNA expression was seen at T₂₄ and T₄₈ but not at T₆ or T₁₂. Among asthmatic patients the effect of Dx on sCD163 production was attenuated in severe in comparison to mild-to-moderate AAs (p = 0.0007). Moreover, Dp-induced production of IL-6 but not IL-10 was inhibited by Dx (p < 0.0001). Inhibition of IL-10 decreased sCD163 concentration by more than 50%.

CONCLUSIONS

Dx-triggered upregulation of anti-inflammatory CD163 expression by monocytes is synergistic with endogenous mechanisms involved in the resolution of Dp-induced inflammation. This effect is impaired in severe asthma patients.

Altered Sphingolipid Metabolism Is Associated With Asthma Phenotype in House Dust Mite-Allergic Patients

Purpose

Sphingolipids play an important role in cell growth, survival, inflammation and tissue remodeling. House dust mite (HDM) allergy is a major risk factor for asthma. The aim of the study was to evaluate if allergic asthma phenotype is associated with altered sphingolipid metabolism.

Methods

Twenty-two HDM-allergic asthmatic patients and 11 HDM-allergic rhinitis patients were challenged intrabronchially with biologically standardized Dermatophagoides pteronyssinus extract. Whole blood and platelet-poor plasma samples were collected before, during early asthmatic response (EAR), late asthmatic response (LAR) and 24 hours after the challenge. Concentrations of sphinganine (SFA), sphinganine-1-phosphate (SFA1P), ceramide, sphingosine (SFO) and sphingosine-1-phosphate (S1P) were measured using high performance liquid chromatography.

Results

In all house dust mite-allergic patients (HDM-APs), baseline lung function and severity of airway hyperreactivity (AHR) correlated significantly with plasma S1P and SFA1P concentrations. Exhaled nitric oxide concentration, however, correlated with SFA and ceramide, but not with S1P or SFA1P concentration. Allergen challenge increased plasma S1P concentration during EAR, but only in patients who developed both EAR and LAR. The magnitude of the increase determined during EAR correlated with the severity of subsequently developed LAR. Platelet and eosinophil counts were independent predictors of plasma S1P concentration. A significant increase in plasma SFA concentration in response to allergen challenge was seen only in patients who did not develop asthmatic response.

Conclusions

Altered sphingolipid metabolism, with augmented synthesis of S1P and impaired de novo sphingolipid synthesis in response to allergen challenge, may participate in the development of asthma phenotype in HDM-APs.

The effect of allergen-induced bronchoconstriction on concentration of 5-oxo-ETE in exhaled breath condensate of house dust mite-allergic patients

BACKGROUND

Arachidonic acid metabolites regulate several aspects of airway function including inflammation, muscle contraction and mucous secretion.

OBJECTIVE

The aim of this study was to evaluate concentration of selected 5-lipoxygenase- and cyclooxygenase-derived eicosanoids in exhaled breath condensate (EBC) during allergen-induced bronchoconstriction.

METHODS

The study was performed on 24 allergic rhinitis/asthma patients sensitized to a house dust mite (HDM) Dermatophagoides pteronyssinus (Dp) and 13 healthy controls (HCs). Bronchial challenge with Dp extract was performed only in the allergic patients. EBC samples were collected before (T₀ ) and during Dp-induced bronchoconstriction (T_EAR ). Eicosanoid concentration was measured using HPLC-tandem mass spectrometry.

RESULTS

Significant bronchoconstriction after Dp challenge was demonstrated in 15 patients (Rs), while in 9 patients (NRs) no asthmatic response could be detected. At T₀ the most abundant eicosanoids in EBC of HDM-allergic patients were LTB₄ and 5-oxo-ETE, while in HCs EBC concentration of LTB₄ was significantly greater than that of 5-oxo-ETE. Allergen challenge resulted in significant increase in EBC concentration of 5-oxo-ETE, LTD₄ and 8-iso-PGE₂ only in Rs. At T_EAR , the relative change of 5-oxo-ETE concentration in EBC correlated with decrease of peripheral blood eosinophilia (R = -0.774; P = .0012). Moreover, the relative increase of 5-oxo-ETE in EBC at T_EAR significantly correlated with the severity of the subsequent late asthmatic response (R = 0.683, P = .007).

CONCLUSION

Our study demonstrates significant up-regulation of 5-oxo-ETE synthesis in HDM-allergic patients and indicates possible involvement of that mediator in the pathogenesis of allergic asthma.

Soluble CD163 modulates cytokine production by peripheral blood mononuclear cells stimulated by Dermatophagoides pteronyssinus allergens in vitro

PURPOSE

The CD163 is a scavenger receptor expressed exclusively on monocytes/macrophages which has been shown to exert anti-inflammatory effects. The aim of this study was to evaluate the effect of exogenous sCD163 on production of selected cytokines by peripheral blood mononuclear cells (PBMC) of house dust mite allergic patients (AAPs) stimulated in vitro with Dermatophagoides pteronyssinus (Dp) allergens.

PATIENTS AND METHODS

The study was performed in 24 AAPs and 12 healthy control subjects (HCs). Peripheral blood mononuclear cells were cultured for up to 144h (T₁₄₄) in the presence of Dp extract with or without sCD163. Concentration of interleukin (IL) - 10, IL-13 and transforming growth factor beta (TGF-β) was evaluated in the cell culture supernatants using ELISA. Expression of the selected cytokines was evaluated in cell culture lysates using Taqman-based real time polymerase chain reaction (RT-PCR).

RESULTS

Dp-stimulated PBMC from AAPs released more IL-10 and IL-13 than those from HCs. The greatest up-regulation of IL-10 expression was seen at T₆, while that of IL-13 was delayed. Soluble CD163 augmented production of IL-10 in response to Dp stimulation. No significant effect of sCD163 on production of IL-13 and IL-10 by PBMC of HCs could be demonstrated.

CONCLUSIONS

In AAPs sCD163 modulates the immune response to Dp allergens potentiating anti-inflammatory, homeostatic mechanisms.

The role of dendritic cells and monocytes in the maintenance and loss of respiratory tolerance

Promoting tolerance to inhaled antigens is an active area of study with the potential to benefit the millions of Americans currently suffering from respiratory allergies and asthma. Interestingly, not all individuals with atopy are symptomatic, arguing that sensitization alone does not lead to an allergic clinical phenotype. Respiratory dendritic cells (rDCs), classically associated with inducing inflammatory responses, can actively promote tolerance. Tolerance can be broken when inflammatory stimuli, including viral infections and other environmental exposures, inhibit rDC-mediated tolerance by allowing innocuous antigen to be presented to initiate type-2 immunity. Importantly, rDCs are composed of multiple subsets, each with a unique response to an inhaled antigen that can lead to either tolerance or inflammation. In this review, we will discuss how rDC subsets actively maintain tolerance or, alternatively, break tolerance in response to environmental cues.

High serum sCD163/sTWEAK ratio is associated with lower risk of digital ulcers but more severe skin disease in patients with systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is an autoimmune disease characterized by chronic inflammation, vascular injury and excessive fibrosis. CD163 is a scavenger receptor which affects inflammatory response and may contribute to connective tissue remodelling. It has recently been demonstrated that CD163 can bind and neutralize the TNF-like weak inducer of apoptosis (TWEAK), a multifunctional cytokine which regulates inflammation, angiogenesis and tissue remodelling. We aimed to investigate the relationships between serum levels of soluble CD163 (sCD163) and soluble TWEAK (sTWEAK) in relation to disease manifestations in SSc patients.

METHODS

This study included 89 patients with SSc who had not received immunosuppressive drugs or steroids for at least 6 months and 48 age- and sex-matched healthy controls (HC) from four European centres. Serum concentrations of sTWEAK and sCD163 were measured using commercially available ELISA kits.

RESULTS

The mean serum concentrations of sTWEAK were comparable between SSc patients (mean +/- SD: 270 +/- 171 pg/mL) and HC (294 +/- 147pg/mL, P >0.05). Concentration of sCD163 and sCD163/sTWEAK ratio were significantly greater in SSc patients (984 +/- 420 ng/mL and 4837 +/- 3103, respectively) as compared to HC (823 +/- 331 ng/mL and 3115 +/- 1346 respectively, P <0.05 for both). High sCD163 levels and a high sCD163/sTWEAK ratio (defined as > mean +2SD of HC) were both associated with a lower risk of digital ulcers in SSc patients (OR, 95%CI: 0.09; 0.01, 0.71, and 0.17; 0.06, 0.51, respectively). Accordingly, patients without digital ulcers had a significantly higher sCD163 concentration and sCD163/sTWEAK ratio as compared to SSc patients with digital ulcers (P <0.01 for both) and HC (P <0.05 for both). A high sCD163/sTWEAK ratio, but not high sCD163 levels, was associated with greater skin involvement.

CONCLUSIONS

The results of our study indicate that CD163-TWEAK interactions might play a role in the pathogenesis of SSc and that CD163 may protect against the development of digital ulcers in SSc. Further studies are required to reveal whether targeting of the CD163-TWEAK pathway might be a potential strategy for treating vascular disease and/or skin fibrosis in SSc.

Concentrations of plasminogen activator inhibitor-1 (PAI-1) and urokinase plasminogen activator (uPA) in induced sputum of asthma patients after allergen challenge

Urokinase plasminogen activator (uPA) and its inhibitor (PAI-1) are involved in tiisue remodeling and repair processes associated with acute and chronic inflammation. The aim of the study was to evaluate the effect of allergen challenge on concentration of uPA and PAI-1 in induced sputum of house dust mite allergic asthmatics (HDM-AAs). Thirty HDM-AAs and ten healthy persons (HCs)were recruited for the study. In 24 HDM-AAs bronchial challenge with Dermatophagoides pteronyssinus (Dp) and in 6 HDM-AAs sham challenege with saline were performed. In HDM-AAs sputum was induced 24 hours before (T0) and 24 hours (T24) after the challenge. Concentration of uPA and PAI-1 in induced sputum were determined using immunoenzymatic assays. At T0 in HDM-AAs mean sputum uPA (151 ± 96 pg/ml) and PAI-1 (4341 ± 1262 pg/ml) concentrations were higher than in HC (18.8 ± 6.7 pg/ml; p=0.0002 and 596 ± 180 pg/ml; p<0.0001; for uPA and PAI-1 respectively). After allergen challenge further increase in sputum uPA (187 ± 144 pg/ml; p=0.03) and PAI-1 (6252 ± 2323 pg/ml; p<0.0001) concentrations were observed. Moreover, in Dp challenged, but not in saline challenged HDM-AAs the mean uPA/PAI-1 ratio decreased significantly at T24. No significant increase in the studied parameters were found in sham challenged patients. In HDM-AAs allergen exposure leads to activation of the plasmin system in the airways. Greater increase of the PAI-1 concentration than uPA concentration after allergen challenge may promote airway remodeling and play an important role in the development of bronchial hyperreactivity.

Exhaled nitric oxide in evaluation of young adults with chronic cough

BACKGROUND

Bronchial asthma (A) is frequently diagnosed in patients with chronic cough. The study was conducted to determine whether an evaluation of fractional exhaled nitric oxide (FeNO) concentration can be used as a screening test for asthma in young adults with chronic cough (CCP).

METHODS

The study was performed on 540 (mean age 26.5; range 18-45 years), nonsmoking young CCP. All patients had resting spirometry within normal limits and no abnormalities on chest radiographs. Skin prick tests with common aeroallergens, bronchial provocation challenge with histamine, and evaluation of FeNO concentration were performed in all patients. One hundred healthy, nonsmoking, nonatopic subjects were used as control subjects (HC).

RESULTS

Asthma (A) was diagnosed in 178 CCP (32.96%). Other frequent diagnoses included rhinitis/sinusitis (R) and gastroesophageal reflux (GERD). The median FeNO concentration in A (86 ppb; 95% CI 72 to 94,5 ppb) was significantly greater than in R (37 ppb; 95% CI 35,6 to 42,9 ppb; p < 0.0001), GERD (14,8 ppb; 95%CI 13.3 to 16.2 ppb; p < 0.0001), or in HC (13 ppb; 95%CI 11 to 15 ppb; p < 0.0001). Significant correlation was found between log(FeNO) and bronchial reactivity expressed as log(PC20) (r = -0.529; 95%CI -0.616 to -0.429; p < 0.0001), but even stronger correlation was demonstrated between log(FeNO) and peripheral blood eosinophilia (r = 0.757; 95%CI 0.717 to 0.792). Receiver Operator Characteristic (ROC) curve analysis revealed that CCP can be screened for A by measuring FeNO concentration. Using 40 ppb as a cut-off value for the FeNO concentration, the specificity 82.6% and sensitivity 88.3% can be achieved.

CONCLUSION

In clinical practice, assessment of FeNO concentration can be used as a screening test for asthma in young adults who have chronic cough.

Enhanced frequencies of CD14++CD16+, but not CD14+CD16+, peripheral blood monocytes in severe asthmatic patients

CD16+ monocytes are expanded in various inflammatory conditions. Recently it was reported that CD16+ monocytes can be divided into two subsets with contrasting potential of modulating inflammatory responses, namely CD14++CD16+ and CD14+CD16+ monocytes. Here, we characterized and quantified CD14++CD16+ and CD14+CD16+ monocyte subsets in asthmatic patients in the context of severity of disease and different treatment options. Subjects included seventeen severe asthmatics and eighteen moderate asthmatics treated with moderate-to-high doses of inhaled glucocorticosteroids (GCS), twenty nine steroid-naive mild asthmatics and fifteen healthy controls. First, we demonstrated that CD14++CD16+ monocytes, in contrast to CD14+CD16+ monocytes, present significantly higher expression of anti-inflammatory molecule CD163. The frequency of CD14++CD16+, but not CD14+CD16+ monocytes, was significantly higher in patients with severe asthma as compared to mild and moderate asthmatics. However, the frequency of both CD16+ monocyte subsets did not correlate directly with exhaled nitric oxide levels. Short-term administration of oral GCS in patients with exacerbations resulted in a preferential decrease of CD14+CD16+ monocytes. Our study indicates that CD14++CD16+ and CD14+CD16+ monocyte subsets in asthmatics are differentially modulated by both the inflammatory process and GCS treatment.

Plasminogen activator inhibitor-1 (PAI-1) and urokinase plasminogen activator (uPA) in sputum of allergic asthma patients

Urokinase plasminogen activator (uPA) and its inhibitor (PAI-1) have been associated with asthma. The aim of this study was to evaluate concentration of uPA and PAI-1 in induced sputum of house dust mite allergic asthmatics (HDM-AAs). The study was performed on 19 HDM-AAs and 8 healthy nonatopic controls (HCs). Concentration of uPA and PAI-1 was evaluated in induced sputum supernatants using ELISA method. In HDM-AAs the median sputum concentration of uPA (128 pg/ml; 95% CI 99 to 183 pg/ml) and PAI-1 (4063 pg/ml; 95%CI 3319 to 4784 pg/ml) were significantly greater than in HCs (17 pg/ml; 95%CI 12 to 32 pg/ml; p<0.001 and 626 pg/ml; 95%CI 357 to 961 pg/ml; p<0.001 for uPA and PAI-1 respectively). The sputum concentration of uPA correlated with sputum total cell count (r=0.781; p=0.0001) and with logarithmically transformed exhaled nitric oxide concentration (eNO) (r=0.486; p=0.035) but not with FEV1 or bronchial reactivity to histamine. On the contrary, the sputum PAI-1 concentration correlated with FEV1 (r=-0,718; p=0.0005) and bronchial reactivity to histamine expressed as log(PC20) (r=-0.824; p<0.0001) but did not correlate with sputum total cell count or eNO. The results of this study support previous observations linking PAI-1 with airway remodeling and uPA with cellular inflammation. Moreover, the observed effect of uPA seems to be independent of its fibrynolytic activity.

Frequencies of circulating CD4+CD25+CD127low cells in atopics are altered by bronchial allergen challenge

BACKGROUND

Recent studies in rodents revealed that regulatory T cells (T reg cells) with CD4+CD25+ phenotype can exert suppressive effects on experimentally-induced allergic airway inflammation and airway hyper-reactivity. It is unclear however, whether modulations of bronchoconstriction responses in human subjects might be related to T reg cells. We report here for the first time the changes in frequency of circulating lymphocytes with putative T reg cell phenotype (CD4+CD25+CD127low) in relation to bronchoconstriction phenotype following an intrabronchial allergen challenge.

MATERIAL AND METHODS

Thirty-one house dust mite sensitive patients were challenged with Dermatophagoides pteronyssinus extract (Dp). Eleven isolated early responders (IER) were compared with nine dual (early and late) responders (DR) and to 11 non-responders (NR). Frequencies of peripheral blood CD4+CD25+CD127low lymphocytes were assessed in all groups of patients by using three-parameter flow cytometry before, and six and 24 h, after allergen inhalation.

RESULTS

At baseline, frequencies of CD4+CD25+CD127low lymphocytes were not statistically different among NR, IER and DR. When all individuals were analyzed together, a statistically significant decrease in frequency of CD4+CD25+CD127low lymphocytes was observed 6 h after the bronchial challenge. Interestingly, such a pattern was found consistently only in NR, while IER and DR displayed varying responses resulting in a trend similar to that of NR. Twenty-four hours after the bronchial challenge, frequencies of CD4+CD25+CD127low lymphocytes in all groups tended to return to baseline values.

CONCLUSIONS

Our data indicate that bronchial allergen inhalation in sensitive patients (predominantly in those who did not develop significant bronchoconstriction) is associated with a decrease of proportion of peripheral lymphocytes with regulatory T cell phenotype.

Proteolytic shedding of the macrophage scavenger receptor CD163 in multiple sclerosis

The scavenger receptor CD163 is selectively expressed on tissue macrophages and human monocytes. CD163 has been implicated to play a role in the clearance of hemoglobin and in the regulation of cytokine production by macrophages. Membrane CD163 can be cleaved by matrix metalloproteinases (MMP) resulting in soluble CD163 (sCD163). In the present report the shedding of CD163 was investigated in multiple sclerosis (MS). An upregulation of plasma sCD163 and a down regulation of membrane CD163 in MS patients compared to healthy controls was observed. The levels of plasma sCD163 correlated with plasma MMP-9 levels in controls, but not in MS patients. Moreover, evidence was obtained for CD163-cleaving MMP activity in plasma of MS patients. Finally, the increased proteolytic shedding of CD163 correlated to reduced plasma levels of circulating inflammatory cytokines. Collectively, our results provide evidence for proteolytic shedding of CD163 in MS and suggest a possible link to cytokine production.