Tofacitinib inhibits the development of experimental autoimmune uveitis and reduces the proportions of Th1 but not of Th17 cells.

Purpose: Tofacitinib is a pan-Janus kinase (JAK) inhibitor that suppresses cytokine signaling and in turn, the cells that participate in inflammatory immunopathogenic processes. We examined the capacity of tofacitinib to inhibit the induction of experimental autoimmune uveitis (EAU) and related immune responses. Methods: EAU was induced in B10.A mice with immunization with bovine interphotoreceptor retinoid-binding protein (IRBP), emulsified in complete Freund's adjuvant (CFA), and a simultaneous injection of pertussis toxin. Tofacitinib, 25 mg/kg, was administered daily, and the vehicle was used for control. EAU development was assessed by histological analysis of the mouse eyes, and related immune responses were assessed by (i) the levels of interferon (IFN)-γ and interleukin (IL)-17, secreted by spleen cells cultured with IRBP; (ii) flow cytometric analysis of intracellular expression by spleen, or eye-infiltrating CD4 or CD8 cells of IFN-γ, IL-17, and their transcription factors, T-bet and RORγt. In addition, the inflammation-related cell markers CD44 and CD62L and Ki67, a proliferation marker, were tested. The proportions of T-regulatory cells expressing FoxP3 were determined by flow cytometric intracellular staining, while levels of antibody to IRBP were measured with enzyme-linked immunosorbent assay (ELISA). Results: Treatment with tofacitinib significantly suppressed the development of EAU and reduced the levels of secreted IFN-γ, but not of IL-17. Further, treatment with tofacitinib reduced in the spleen and eye-infiltrating cells the intracellular expression of IFN-γ and its transcription factor T-bet. In contrast, treatment with tofacitinib had essentially no effect on the intracellular expression of IL-17 and its transcription factor, RORγt. The selective effect of tofacitinib treatment was particularly evident in the CD8 population. Treatment with tofacitinib also increased the population of CD44, but reduced the populations of cells producing CD62L and Ki67. Treatment with tofacitinib had no effect on the proportion of FoxP3 producing regulatory cells and on the antibody production to IRBP. Conclusions: Treatment with tofacitinib inhibited the development of EAU, reduced the production of IFN-γ, but had essentially no effect on the production of IL-17.

L-Selectin P213S and Integrin Alpha 2 C807T Genetic Polymorphisms in Pediatric Sickle Cell Disease Patients.

Sickle cell disease (SCD) is an autosomal recessive hemoglobinopathy characterized by increased cellular adhesiveness. Vaso-occlusion (VOC) is the most prevalent disease complication of SCD that could be altered by genetic factors. L-Selectin and integrin alpha 2 (ITGA2) are 2 adhesion molecules linked to vasculopathy and inflammation. The current study aimed at detecting the prevalence of genetic variants of L-selectin and ITGA2 as possible molecular modulators and novel therapeutic targets in a cohort of pediatric SCD patients. Genotyping was performed by polymerase chain reaction restriction fragment length polymorphism technique for 100 SCD patients and 100 age and gender-matched unrelated healthy controls. The homomutant genotype of ITGA2 C807T was significantly higher in SCD patients compared with controls (P=0.001) and confirmed almost a 3-fold increased risk of moderate and severe attacks of VOC. There are significant adverse effects caused by the polymorphisms of ITGA2, and hence Egyptian SCD patients could benefit from the targeted therapies specifically against ITGA2 to ameliorate the severe course of the disease and improve the quality of life. However, further studies of genotypes and expression levels of these adhesion molecules during the attacks of VOC are recommended.

Inflammatory responses to acute exercise during pulmonary rehabilitation in patients with COPD.

OBJECTIVE: Pulmonary rehabilitation is a cornerstone treatment in the management of chronic obstructive pulmonary disease (COPD). Acute bouts of exercise can lead to short bursts of inflammation in healthy individuals. However, it is unclear how COPD patients respond to acute bouts of exercise. This study assessed inflammatory responses to exercise in COPD patients at the start (phase 1) and end (phase 2) of pulmonary rehabilitation. METHODS: Blood samples were collected before and after an acute exercise bout at the start (phase 1, n = 40) and end (phase 2, n = 27) of pulmonary rehabilitation. The primary outcome was change in fibrinogen concentrations. Secondary outcomes were changes in CRP concentrations, total/differential leukocyte counts, markers of neutrophil activation (CD11b, CD62L and CD66b), and neutrophil subsets (mature, suppressive, immature, progenitor). RESULTS: Acute exercise (phase 1) did not induce significant changes in fibrinogen (p = 0.242) or CRP (p = 0.476). Total leukocyte count [mean difference (MD), 0.5 ± 1.1 (109 L-1); p = 0.004], neutrophil count [MD, 0.4 ± 0.8 (109 L-1); p < 0.001], and immature neutrophils (MD, 0.6 ± 0.8%; p < 0.001) increased post-exercise. Neutrophil activation markers, CD11b (p = 0.470), CD66b (p = 0.334), and CD62L (p = 0.352) were not significantly altered post-exercise. In comparison to the start of pulmonary rehabilitation (phase 2), acute exercise at the end of pulmonary rehabilitation led to a greater fibrinogen response (MD, 84 mg/dL (95% CI - 14, 182); p = 0.045). CONCLUSION: An acute bout of exercise does not appear to induce significant alterations in the concentrations of inflammatory mediators but can increase white blood cell subsets post-exercise. A greater fibrinogen response to acute exercise is seen at the end of pulmonary rehabilitation when compared to the start. Further research is required to understand the clinical context of these acute inflammatory responses to exercise.

Intestinal injury and gut permeability in sickle cell disease.

BACKGROUND: Due to recurrent hypoxia-reperfusion injury induced by vaso-occlusive crises (VOC), patients with sickle cell disease (SCD) may have intestinal injury and increased permeability. These may explain the qualitative and quantitative neutrophil abnormalities observed in these patients. METHODS: Serum intestinal fatty-acid binding protein (iFABP), lipopolysaccharides (LPS), and CD62L were measured by ELISA. Multicolor flow cytometry was used to measure circulating aged neutrophils. RESULTS: Compared to controls, SCD individuals had higher iFABP (median: 1.38 ng/ml vs 0.81 ng/ml; p = 0.04) and LPS (median: 2.15 µg/ml vs 0.69 µg/ml; p = 0.03), indicating intestinal injury and increased intestinal bacterial translocation into the systemic circulation. They also had higher soluble CD62L (median: 1.38 µg/ml vs 1.11 µg/ml; p = 0.04). Among SCD individuals, soluble CD62L correlated positively with circulating aged neutrophils (R = 0.7, p = 0.03) and LPS (R = 0.66, p = 0.027). Surprisingly, serum iFABP in SCD correlated negatively with both LPS (R = - 0.7, p = 0.02) and soluble CD62L (R = - 0.56, p = 0.08). CONCLUSIONS: Since LPS translocation across the intestinal barrier may be due to increases in the intestinal bacterial density, gut permeability, or both, the negative correlations between iFABP and LPS, and CD62L raise the possibility that any damage-associated molecular patterns induced by intestinal injury may modulate the degree of bacterial translocation. Our results provide the first evidence of the presence of intestinal injury and increased gut permeability in SCD.

Erythrocyte sialoglycoproteins engage Siglec-9 on neutrophils to suppress activation.

Healthy blood neutrophils are functionally quiescent in the bloodstream, have a short lifespan, and exit the circulation to carry out innate immune functions, or undergo rapid apoptosis and macrophage-mediated clearance to mitigate host tissue damage. Limitation of unnecessary intravascular neutrophil activation is also important to prevent serious inflammatory pathologies. Because neutrophils become easily activated after purification, we carried out ex vivo comparisons with neutrophils maintained in whole blood. We found a difference in activation state, with purified neutrophils showing signs of increased reactivity: shedding of l-selectin, CD11b upregulation, increased oxidative burst, and faster progression to apoptosis. We discovered that erythrocytes suppressed neutrophil activation ex vivo and in vitro, including reduced l-selectin shedding, oxidative burst, chemotaxis, neutrophil extracellular trap formation, bacterial killing, and induction of apoptosis. Selective and specific modification of sialic acid side chains on erythrocyte surfaces with mild sodium metaperiodate oxidation followed by aldehyde quenching with 4-methyl-3-thiosemicarbazide reduced neutrophil binding to erythrocytes and restored neutrophil activation. By enzyme-linked immunosorbent assay and immunofluorescence, we found that glycophorin A, the most abundant sialoglycoprotein on erythrocytes, engaged neutrophil Siglec-9, a sialic acid-recognizing receptor known to dampen innate immune cell activation. These studies demonstrate a previously unsuspected role for erythrocytes in suppressing neutrophils ex vivo and in vitro and help explain why neutrophils become easily activated after separation from whole blood. We propose that a sialic acid-based "self-associated molecular pattern" on erythrocytes also helps maintain neutrophil quiescence in the bloodstream. Our findings may be relevant to some prior experimental and clinical studies of neutrophils.

Differential phenotype of immune cells in blood and milk following pegylated granulocyte colony-stimulating factor therapy during a chronic Staphylococcus aureus infection in lactating Holsteins.

Neutrophils are principal host innate immune cell responders to mastitis infections. Thus, therapies have been developed that target neutrophil expansion. This includes the neutrophil-stimulating cytokine granulocyte colony-stimulating factor (gCSF). Pegylated gCSF (PEG-gCSF; Imrestor, Elanco Animal Health, Greenfield, IN) has been shown to reduce the natural incidence of mastitis in periparturient cows in commercial settings and reduce severity of disease against experimental mastitis challenge. Pegylated gCSF stimulates neutrophil expansion but also induces changes in monocyte and lymphocyte circulating numbers, surface protein expression changes, or both. We hypothesized that PEG-gCSF modulates surface expression of monocytes and neutrophils and facilitates their migration to the mammary gland. We challenged 8 mid-lactation Holsteins with approximately 150 cfu of Staphylococcus aureus (Newbould 305) in a single quarter via intramammary infusion. All animals developed chronic infections as assessed by bacteria counts and somatic cell counts (SCC). Ten to 16 wk postchallenge, 4 of the animals were treated with 2 subcutaneous injections of PEG-gCSF 7 d apart. Complete blood counts, SCC, bacterial counts, milk yield, feed intake, neutrophils extracellular trap analysis, and flow cytometric analyses of milk and blood samples were performed at indicated time points for 14 d after the first PEG-gCSF injection. The PEG-gCSF-treated cows had significantly increased numbers of blood neutrophils and lymphocytes compared with control cows. Flow cytometric analyses revealed increased surface expression of myeloperoxidase (MPO) on neutrophils and macrophages in milk but not in blood of treated cows. Neutrophils isolated from blood of PEG-gCSF-treated cows had decreased surface expression of CD62L (L-selectin) in blood, consistent with cell activation. Surprisingly, CD62L cell surface expression was increased on neutrophils and macrophages sourced from milk from treated animals compared with cells isolated from controls. The PEG-gCSF-treated cows did not clear the S. aureus infection, nor did they significantly differ in SCC from controls. These findings provide evidence that PEG-gCSF therapy modifies cell surface expression of neutrophils and monocytes. However, although surface MPO+ cells accumulate in the mammary gland, the lack of bacterial control from these milk-derived cells suggests an incomplete role for PEG-gCSF treatment against chronic S. aureus infection and possibly chronic mammary infections in general.

Natural killer cells are pivotal for in vivo protection following systemic infection by Sporothrix schenckii.

Natural killer (NK) cells are one of the first cell types to enter inflammation sites and have been historically known as key effector cells against tumours and viruses; now, accumulating evidence shows that NK cells are also capable of direct in vitro activity and play a protective role against clinically important fungi in vivo. However, our understanding of NK cell development, maturation and activation in the setting of fungal infections is preliminary at best. Sporotrichosis is an emerging worldwide-distributed subcutaneous mycosis endemic in many countries, affecting humans and other animals and caused by various related thermodimorphic Sporothrix species, whose prototypical member is Sporothrix schenckii. We show that following systemic infection of BALB/c mice with S. schenckii sensu stricto, NK cells displayed a more mature phenotype as early as 5 days post-infection as judged by CD11b/CD27 expression. At 10 days post-infection, NK cells had increased expression of CD62 ligand (CD62L) and killer cell lectin-like receptor subfamily G member 1 (KLRG1), but not of CD25 or CD69. Depletion of NK cells with anti-asialo GM1 drastically impaired fungal clearance, leading to a more than eightfold increase in splenic fungal load accompanied by heightened systemic inflammation, as shown by augmented production of the pro-inflammatory cytokines tumour necrosis factor-α, interferon-γ and interleukin-6, but not interleukin-17A, in the spleen and serum. Our study is, to the best of our knowledge, the first to demonstrate that a fungal infection can drive NK cell maturation in vivo and that such cells are pivotal for in vivo protection against S. schenckii.

Associations between chronic caregiving stress and T cell markers implicated in immunosenescence.

Chronic psychological stress is associated with accelerated biological aging, immune dysfunction, and premature morbidity and mortality. Changes in the relative proportions of T cell subpopulations are thought to be a characteristic of immunological aging; however, understanding of whether these changes are associated with chronic psychological stress is incomplete. This study investigated associations between chronic caregiving stress and distributions of T cell phenotypes in a sample of high stress mothers of children with Autism Spectrum Disorder (caregivers; n = 91) and low stress mothers of neurotypical children (controls; n = 88). Immune markers assessed were naïve (CD45RA + CD62L+), central memory (CD45RA-CD62L+), and effector memory (CD45RA-CD62L-) CD4+ and CD8+ T cells. We also examined the ratio of effector to naïve (E:N) CD4+ and CD8+ T cells. In models adjusted for age, body mass index, race/ethnicity, and antidepressant use, caregivers displayed higher percentages of effector memory CD8+ and CD4+ T cells as well as lower percentages of naïve CD8+ T cells and central memory CD8+ and CD4+ T cells compared to controls. Caregivers also displayed significantly higher E:N ratios for both CD4+ and CD8+ T cells. These findings were also independent of cytomegalovirus infection status. Furthermore, higher parental stress, across both groups, was related to several immune parameters. These findings provide preliminary evidence that chronic parental caregiving stress is associated with changes in relative proportions of T cell subpopulations that are consistent with accelerated immunological aging.

A novel and accurate microfluidic assay of CD62L in bladder cancer serum samples.

We report a low-cost, sensitive, bead-based electrochemical immunoarray for soluble L-selectin (or CD62L protein), a potential biomarker for staging bladder cancer. We used a semi-automated modular microfluidic array with online antigen capture on superparamagnetic beads, which were subsequently delivered to a detection chamber housing multiple sensors. The assay was designed to accurately detect CD62L in diluted serum with a limit of detection (LOD) of 0.25 ng mL-1 and a dynamic range of 0.25-100 ng mL-1. The microfluidic array gave significantly better accuracy and higher sensitivity than a standard ELISA kit, which was shown to be subject to significant systematic error at high and low concentration ranges. 31 serum samples from patients with varying grades of bladder cancer and cancer-free controls were analyzed by the immunoarray and ELISA, and the CD62L levels correlated. This work establishes a new accurate assay for determining CD62L levels and highlights the potential of this protein as a biomarker for detecting locoregional progression of bladder cancer.

Neutrophil activation during acute human anaphylaxis: analysis of MPO and sCD62L.

BACKGROUND: The mechanisms involved in the amplification of the mast cell response during anaphylaxis are unclear. Mouse models of anaphylaxis demonstrate the critical involvement of neutrophils. These innate immune cells are highly abundant in peripheral blood and can be rapidly activated to trigger both local and systemic inflammation. OBJECTIVE: To investigate neutrophil activation in peripheral blood during acute human anaphylaxis. METHODS: Patients presenting to the emergency department with anaphylaxis underwent blood sampling upon enrolment and at up to three subsequent time-points. Traditional anaphylaxis biomarkers, histamine and mast cell tryptase, were measured by ELISA and ImmunoCAP, respectively. Plasma myeloperoxidase concentrations were measured by ELISA, serum soluble CD62L concentrations by cytometric bead array, and both compared to healthy controls. RESULTS: In 72 patients, 37 (51%) had severe anaphylaxis, 33 (60%) were histamine positive, and 47 (70%) were mast cell tryptase positive. At enrolment, myeloperoxidase concentrations were 2.9- (95% CI: 1.3, 6.5) and 5.0- (95% CI: 2.4, 10.5) fold higher in moderate and severe patients, respectively, compared with healthy controls, and remained stable over the first 5 h following symptom onset. At enrolment, soluble CD62L was 29% (95% CI: 19, 38) and 31% (95% CI: 22, 40) lower in moderate and severe patients, respectively, than healthy controls, and was stable over the first 5 h. There were no associations between myeloperoxidase or soluble CD62L concentrations and either histamine or mast cell tryptase concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: These results provide compelling evidence for the involvement of neutrophils during acute human anaphylaxis, suggesting they are activated early in the reaction, regardless of mast cell activation. This important finding increases our understanding of the basic mechanisms of anaphylaxis, a necessary precursor to improving treatment and prevention.

Altered basophil function in patients with chronic kidney disease on hemodialysis
.

AIMS: Chronic kidney disease (CKD) leads to impairment of immune cell function. Given the potential role of basophils in the pathogenesis of CKD, we aimed to study the basophil responsiveness towards microbial antigen exposure, judged as adhesion molecule expression and degranulation, in CKD patients on hemodialysis. MATERIALS AND METHODS: We selected markers linked to two crucial biological phases: the transmigration and degranulation processes, respectively. For the transmigration process, we selected the adhesion molecules CD11b, active CD11b epitope, and CD62L and for the degranulation process CD203c (piecemeal degranulation marker), CD63 (degranulation marker), and CD300a (inhibitory marker of degranulation). We measured basophil responsiveness after stimulation of different activation pathways in basophils using lipopolysaccharide (LPS), peptidoglycan (PGN), formyl-methyinoyl-leucyl-phenylalanine (fMLP), and anti-FcεRI-ab. RESULTS: The expression of CD63 in basophils following activation by fMLP was significantly higher in the patient group compared to matched healthy controls, but no differences were observed after activation by anti-FcɛI. CD300a expression was significantly higher in patients following activation by fMLP and anti-FcɛI, and the active epitope CD11b expression was significantly higher in patients after LPS activation. In addition, we found that CD62L was not shed from the cell surface after activation with LPS and fMLP. A slight downregulation was noted after activation with anti-FcɛI in healthy controls. CONCLUSION: Together, these data demonstrate that basophil functions related to adhesion and degranulation are altered in CKD patients on hemodialysis, which indicates a potential role for the basophil in the pathogenesis of complications related to infections.

[THE LEVEL OF EXPRESSION OF MOLECULES OF ADHESION ON LYMPHOCYTES DEPENDING ON AMOUNT OF THEIR CYTOPLASM].

The lymphocytes are true immunocytes specialized in discerning antigen in organism. Their behavior in blood is regulated by several classes of adhesion proteins, including selectin, integrin, immunoglobulin. In healthy humans there is no data concerning level of expression of adhesion molecules on lymphocytes depending on size of their cytoplasm. The study was carried out to determine level of expression of adhesion molecules of lymphocytes depending on size of their cytoplasm. The flow cytometer was applied to determine in venous blood level of expression of adhesion molecules in 50 individuals (22 males and 28 females) aged from 20 to 60 years and having no chronic pathology in anamnesis. The analysis of lymphocytogram permitted to differentiate lymphocytes according volume of cell considering size of cytoplasm: small lymphocytes- up to 8 mkm; medium - from 8 to 12 mkm; large - more than 12 mkm. In males a tendency was established concerning decreasing of concentration of lymphocytes with expressed molecule of L-selectin. The absence was detected concerning gender differences in level of lymphocytes with receptor LFA-1 and also lymphocytes with molecule ICAM-1. In males concentration of lymphocytes with receptor LFA-3 was higher than in females but only as a tendency. The lower level of expression of molecule PECAM-1 in males was observed. The correlation analysis between level of expresion of adhesion molecules and concentration of lymphocytes differing in size of cytoplasm, demonstrated that at increasing of size of cytoplasm of lymphocytes increases number of statistically reliable correlations. The shedding of molecules of L-selectin in lymphocytes proceeds significantly more active than in monocytes. At that, medium plasma lymphocytes and large granular lymphocytes identified as natural killers are more predisposed to migration. However, lymphocytes entering condition of lympho-proliferation have less ability to adhesion.

Selective subepicardial localization of monocyte subsets in response to progressive coronary artery constriction.

Following myocardial infarction and atherosclerotic lesion development, monocytes contribute to myocardial protection and repair, while also partaking in myocardial ischemic injury. The balance of proinflammatory and reparative monocyte subsets is crucial in governing these therapeutic and pathological outcomes. Myocardial ischemic damage displays heterogeneity across the myocardium, whereby the subendocardium shows greatest vulnerability to ischemic damage. In this study we examined the transmural distribution of monocyte subsets in response to gradual coronary artery occlusion. CD14(+) monocytes were isolated from peripheral blood of New Zealand White rabbits and divided into two subgroups based on the expression of CD62L. We employed a rabbit model of progressive coronary artery obstruction to induce chronic myocardial ischemia and reinfused fluorescently labeled autologous monocytes. The distribution of fluorescently labeled autologous monocytes was examined with a high-resolution three-dimensional imaging cryomicrotome. The subepicardial layer contained the largest infiltration of both monocyte subgroups, with a significantly greater proportion of CD14(+)CD62L(+) monocytes at the time when the ischemic area was at a maximum. By targeting CD13(+) angiogenic vessels, we confirmed the presence of angiogenesis in epicardial and midmyocardial regions. These myocardial regions demonstrated the highest level of infiltration of both monocyte subsets. Furthermore, CD14(+)CD62L(+) monocytes showed significantly greater migration towards monocyte chemoattractant protein-1, greater adhesive capacity, and higher expression of C-C chemokine receptor type-2 relative to CD14(+)CD62L(-) monocytes. In conclusion, we note selective subepicardial distribution of monocyte subpopulations, with changes in proportion depending on the time after onset of coronary narrowing. Selective homing is supported by divergent migratory properties of each respective monocyte subgroup.

Early Changes in Monocyte Adhesion Molecule Expression and Tumor Necrosis Factor-α Levels in Chronic Kidney Disease - A 5-Year Prospective Study.

BACKGROUND: Despite the absence of clinical symptoms, patients with chronic kidney disease (CKD) exhibit elevated levels of pro-inflammatory markers. To investigate whether it is possible to detect inflammatory activity and altered monocyte function at an early stage of renal disease, we studied patients with CKD stages 2-3 over 5 years. METHODS: The expression of adhesion molecules on monocytes at resting state and after stimulation with formyl-methionyl-leucyl-phenylalanine (fMLP), as well as oxidative metabolism capacity was measured with flow cytometry in 108 CKD patients and healthy controls. Soluble markers of inflammation, such as cytokines, were analyzed using the Milliplex technique. RESULTS: Patients showed significantly lower CD11b expression after stimulation during the 3rd (p = 0.002) and the 5th year (p < 0.001), together with a lower oxidative burst in response to fMLP over time (p = 0.02). The expression of CD62L on resting monocytes was lower during the 3rd (p = 0.001) and the 5th (p = 0.001) year in patients. Levels of tumor necrosis factor-α and RANTES were significantly increased (p = 0.001, p = 0.006) and interleukin-12 levels were also higher in CKD patients during the 5th year (p = 0.007). CONCLUSION: Monocytes in CKD stages 2-3 show emerging functional abrasions, with altered adhesion molecule expression and impaired fMLP response. These findings suggest that a transformation of monocyte function occurs at an early phase of renal impairment and may together with increased plasma levels of pro-inflammatory cytokines contribute to the higher vulnerability of CKD patients to comorbidities, such as infections and cardiovascular disease.

Circulating cellular adhesion molecules and risk of diabetes: the Multi-Ethnic Study of Atherosclerosis (MESA).

AIMS: To test the hypothesis that soluble cellular adhesion molecules would be positively and independently associated with risk of diabetes. METHODS: Soluble levels of six cellular adhesion molecules (ICAM-1, E-selectin, VCAM-1, E-cadherin, L-selectin and P-selectin) were measured in participants in the Multi-Ethnic Study of Atherosclerosis, a prospective cohort study. Participants were then followed for up to 10 years to ascertain incident diabetes. RESULTS: Sample sizes ranged from 826 to 2185. After adjusting for age, sex, race/ethnicity, BMI and fasting glucose or HbA1c , four cellular adhesion molecules (ICAM-1, E-selectin, VCAM-1 and E-cadherin) were positively associated with incident diabetes and there was a statistically significant trend across quartiles. Comparing the incidence of diabetes in the highest and lowest quartiles of each cellular adhesion molecule, the magnitude of association was largest for E-selectin (hazard ratio 2.49; 95% CI 1.26-4.93) and ICAM-1 (hazard ratio 1.76; 95% CI 1.22-2.55) in fully adjusted models. Tests of effect modification by racial/ethnic group and sex were not statistically significant for any of the cellular adhesion molecules (P > 0.05). CONCLUSIONS: The finding of significant associations between multiple cellular adhesion molecules and incident diabetes may lend further support to the hypothesis that microvascular endothelial dysfunction contributes to risk of diabetes.

PML risk stratification using anti-JCV antibody index and L-selectin.

BACKGROUND: Natalizumab treatment is associated with progressive multifocal leukoencephalopathy (PML) development. Treatment duration, prior immunosuppressant use, and JCV serostatus are currently used for risk stratification, but PML incidence stays high. Anti-JCV antibody index and L-selectin (CD62L) have been proposed as additional risk stratification parameters. OBJECTIVE: This study aimed at verifying and integrating both parameters into one algorithm for risk stratification. METHODS: Multicentric, international cohorts of natalizumab-treated MS patients were assessed for JCV index (1921 control patients and nine pre-PML patients) and CD62L (1410 control patients and 17 pre-PML patients). RESULTS: CD62L values correlate with JCV serostatus, as well as JCV index values. Low CD62L in natalizumab-treated patients was confirmed and validated as a biomarker for PML risk with the risk factor "CD62L low" increasing a patient's relative risk 55-fold (p < 0.0001). Validation efforts established 86% sensitivity/91% specificity for CD62L and 100% sensitivity/59% specificity for JCV index as predictors of PML. Using both parameters identified 1.9% of natalizumab-treated patients in the reference center as the risk group. CONCLUSIONS: Both JCV index and CD62L have merit for risk stratification and share a potential biological relationship with implications for general PML etiology. A risk algorithm incorporating both biomarkers could strongly reduce PML incidence.

Investigational analysis reveals a potential role for neutrophils in giant-cell arteritis disease progression.

RATIONALE: Giant-cell arteritis (GCA) is a large-vessel vasculitis characterized by immune cell infiltration, yet the potential involvement of neutrophils has rarely been studied. OBJECTIVE: We investigated whether alterations in neutrophil reactivity occurred in the pathogenesis of GCA or during its clinical management with a canonical glucocorticoid dose regimen during a 6-month period. METHODS AND RESULTS: Blood samples were taken within 48 hours of therapy commencement and at weeks 1, 4, and 24 after glucocorticoid dose. Flow cytometric analysis revealed 3 distinct neutrophil populations and phenotypes. Within 48 hours of steroid treatment, neutrophils displayed an AnxA1(hi)CD62L(lo)CD11b(hi) phenotype, whereas week 1 neutrophils were AnxA1(hi)CD62L(lo)CD11b(lo) and displayed minimal adhesion to endothelial monolayers under flow, and week 24 (i.e., lowest glucocorticoid dose) neutrophils were AnxA1(hi)CD62L(hi)CD11b(hi) with increased endothelial adhesion under flow. Week 24 plasma analyses showed high levels of C-X-C motif chemokine ligand 5, interleukin (IL) 8, IL-17, and IL-6. Importantly, comparison of week 1 and week 24 samples revealed a suppressive neutrophil effect on T-cell proliferation at the former time point only. Finally, in vitro incubation of naive neutrophils with concentrations of IL-6 and IL-17 quantified in GCA plasma at weeks 1 and 24 replicated this differential modulation of lymphocyte proliferation. CONCLUSIONS: This translational study highlights a novel clinical manifestation of GCA, with evidence for a neutrophil component and an escaped proinflammatory phenotype when glucocorticoid therapy is tapered. These results indicate potential involvement of neutrophils in GCA pathogenesis.

Inhaled corticosteroids increase blood neutrophil count by decreasing the expression of neutrophil adhesion molecules Mac-1 and L-selectin.

OBJECTIVE: The objective was to investigate the effect of commonly used inhaled corticosteroids on white blood cell count (WBC) and to examine the mechanisms involved. METHODS: This randomized comparative study comprised 60 healthy adults. We measured the effects of budesonide (by face mask inhalation or aerosol inhaler), fluticasone (by inhaler), and saline inhalation (control) on WBC and the differential leukocyte count, especially the absolute neutrophil count (ANC). To elucidate the mechanisms involved, we measured the expression of the adhesion neutrophil ligands Mac-1 (CD11b) and L-selectin (CD62L), and granulocyte colony-stimulating factor serum levels. RESULTS: Six hours after a single-dose inhalation of budesonide, mean increases of 23.4% in WBC (95% confidence interval [CI], 11.3-35.4) and 30.1% in ANC (95% CI, 7.2-53.0) were noted. The percentage of neutrophils increased from 54.6% to 58.1% (P< .001). Inhaled fluticasone increased WBC and ANC by 12.6% (95% CI, 1.5-23.7) and 22.7% (95% CI, 6.2-39.2), respectively (P< .01 for both). The absolute lymphocyte and eosinophil counts did not change significantly from baseline. The expression of Mac-1 and L-selectin decreased by 51.0% (P< .01) and 30.9% (P= .02), respectively, following face mask inhalation of budesonide and by 39.8% (P= .01) and 17.4% (P= .17), respectively, following inhalation of fluticasone. No significant changes in granulocyte colony-stimulating factor levels were noted. CONCLUSIONS: Glucocorticoid inhalation increases WBC by increasing ANC. Reduced neutrophil adhesion to the endothelial surface, mediated by decreased adhesion molecule expression on neutrophils, is a plausible mechanism. Physicians should be aware of the effect of inhaled corticosteroids on WBC, as it may influence clinical decisions, especially in the emergency department.

Effects of 3 sequestering agents on milk aflatoxin M1 concentration and the performance and immune status of dairy cows fed diets artificially contaminated with aflatoxin B1.

This study examined whether adding 3 mycotoxin-sequestering agents to diets contaminated with aflatoxin B1 (AFB1) would reduce milk aflatoxin M1 (AFM1) concentration, and improve the performance and alter immune status of dairy cows. Fifteen lactating dairy cows were used in an experiment with an incomplete crossover design including four 28-d periods. Treatments included a control diet (C), a toxin diet (T; 1,725µg of AFB1/head per day; 75µg/kg), and diets containing the toxin and 20g/head per day of a proprietary mixture of Saccharomyces cerevisiae fermentation product containing a low (SEQ1) or high (SEQ2) dose of a chlorophyll-based additive, or a low dose of the chlorophyll-based additive and sodium bentonite clay (SEQ3). Sequestering agents were top-dressed on the total mixed ration (TMR) daily in each period, and AFB1 was dosed orally in gelatin capsules before the TMR was fed on d 21 to 25. Milk was sampled twice daily on d 20 to 28 and plasma was sampled on d 20 and 25. Sequestering agents did not affect milk AFM1 concentration during the toxin-dosing period. However, after AFB1 was withdrawn, the sequestering agents reduced the time required (24 vs. 48h) to reduce the milk AFM1 concentration below the Food and Drug Administration action level of 0.5µg/kg. Feeding T instead of C tended to reduce milk and fat-corrected milk yields, but feeding SEQ1 prevented these effects. Red blood cell count and hemoglobin concentration were reduced by feeding T instead of C, but not by feeding SEQ1, SEQ2, or SEQ3. The mean fluorescence intensity of antibody staining for 2 leukocyte adhesion molecules, L-selectin (CD62L) and ß-integrin (CD18), tended to be greatest when SEQ1 and SEQ3 were fed. Plasma acid-soluble protein concentration was decreased by feeding SEQ1, SEQ2, and SEQ3 instead of T. Sequestering agents had no effect on milk AFM1 concentration, but they reduced the time required to reduce milk AFM1 concentration to a safe level after withdrawal of AFB1 from the diet. Only SEQ1 prevented the adverse effects of AFB1 on milk and fat-corrected milk yields.

A novel splice variant of human L-selectin encodes a soluble molecule that is elevated in serum of patients with rheumatic diseases.

L-selectin, a type I membrane protein, is a leukocyte adhesion molecule that mediates both lymphocyte homing to peripheral lymph nodes and leukocyte accumulation at sites of inflammation. L-selectin is rapidly shed from the cell surface after cellular activation, and the ectodomain thus released is thought to account for high levels of soluble L-selectin in serum. In this study, we report the identification of a novel, naturally occurring isoform of the human L-selectin gene. Sequence analysis revealed that this isoform is generated by an alternative splicing event: the 7th exon of the human L-selectin gene, which encodes the region containing the transmembrane domain, is excluded, predicting a soluble protein product. The mRNA for this splice variant was expressed in lymphoid organs, where conventional L-selectin mRNA was also expressed. Activating T cells increased the variant mRNA and its ratio to the membrane form. Soluble L-selectin translated from the variant mRNA was present in human serum, albeit at a much lower level than that arising from ectodomain shedding, and was markedly elevated in patients with various rheumatic diseases, including rheumatoid arthritis and systemic lupus erythematosus. These observations indicate that some of the soluble L-selectin present in human serum arises through alternative splicing, which may be upregulated during lymphocyte activation in patients with various clinical conditions.