Cerivastatin and atorvastatin inhibit IL-3-dependent differentiation and IgE-mediated histamine release in human basophils and downmodulate expression of the basophil-activation antigen CD203c/E-NPP3

Basophil activation test: Assay precision and BI 1002494 SYK inhibition in healthy and mild asthmatics

BACKGROUND

Application of basophil activation test (BAT) in clinical trials requires assay validity. Whether assay variability differs between healthy and asthmatic subjects is mostly unknown. This study compares basophil stimulation using blood from healthy and asthmatic subjects with or without inhibition of spleen tyrosine kinase (SYK).

METHODS

Whole blood of healthy and mild asthmatic subjects was stimulated with anti-dinitrophenyl (DNP) IgE/DNP bovine serum albumin and anti-IgE. Basophil activation was detected by CD63 and CD203c expression. CD63 expression levels were compared with serum IgE levels. Three operators repeated experiments with three subjects each from both groups at 3 days to observe assay precision. The effect of the SYK inhibitor BI 1002494 was assessed in BAT for both healthy and asthmatic subjects.

RESULTS

BAT was reproducible in both groups. Acceptance criteria of <25% CV were mostly fulfilled. Stimulation with anti-DNP (p < 0.001, r = -0.80) but not anti-IgE (p = 0.74, r = 0.05) was related to serum IgE with levels > 200 IU/ml limiting anti-DNP stimulation. BI 1002494 IC₅₀ values were 497 nM and 1080 nM in healthy and 287 nM and 683 nM in asthmatics for anti-DNP and anti-IgE stimulation, respectively.

CONCLUSION

BAT, performed with blood from healthy or asthmatic subjects, is a robust test for the measurement of a physiological response in clinical trials. Blood from asthmatic donors with serum IgE > 200 IU/ml is less feasible when using anti-DNP stimulation. SYK inhibition was not affected by disease status.

Effect of atorvastatin on humoral immune response to 23-valent pneumococcal polysaccharide vaccination in healthy volunteers: The StatVax randomized clinical trial

BACKGROUND

The immunomodulatory effects of statins on vaccine response remain uncertain. Therefore, the objective of this study was to determine if atorvastatin enhances pneumococcal-specific antibody titer following 23-valent pneumococcal polysaccharide vaccination.

METHODS

Double-blind, placebo-controlled, single-center randomized clinical trial entitled StatVax. Subjects were enrolled between June and July 2014 and followed up through September 2014. 33 healthy volunteers signed informed consent after volunteer sampling. 11 participants were excluded; 22 healthy volunteers without prior pneumococcal vaccination were enrolled and completed the study. Participants were randomized to receive a 28-day course of 40 mg atorvastatin (n = 12) or matching lactose placebo (n = 10). On day 7 of treatment, Pneumovax 23 was administered intramuscularly. The primary outcome was fold change in total pneumococcal-specific antibody titer determined by a ratio of post-vaccination titer over baseline titer. Secondary outcomes included serotype-specific pneumococcal antibody titer, seroconversion, complete blood counts (CBC), erythrocyte sedimentation rate (ESR), and serum cytokine analysis.

RESULTS

Of the 22 randomized patients (mean age, 23.86; SD, 4.121; 11 women [50%]), 22 completed the trial. Total anti-pneumococcal antibody titer in the atorvastatin group went from a baseline mean of 32.58 (SD, 15.96) to 147.7 (SD, 71.52) μg/mL at 21 days post-vaccination while titer in the placebo group went from a mean of 30.81 (SD, 13.04) to 104.4 (SD, 45) μg/mL. When comparing fold change between treatment groups, there was a significant increase in fold change of total anti-pneumococcal antibody titer in the atorvastatin group compared to the placebo group (2-way ANOVA, p = .0177).

CONCLUSIONS

Atorvastatin enhances antigen-specific primary humoral immune response to a T cell-independent pneumonia vaccination. Pending confirmation by larger cohort studies of target populations, peri-vaccination conventional doses of statins can become a novel adjuvant for poorly-immunogenic polysaccharide-based vaccines.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02097589.

Exploratory analysis of CD63 and CD203c expression in basophils from hazelnut sensitized and allergic individuals

Background

Sensitization to hazelnut (HN) is frequent and requires clarification to determine whether this sensitization is clinically relevant. The aim of this study was to investigate basophil activation profiles in HN-sensitized and allergic subjects.

Methods

Basophil activation was determined by flow cytometric analyses of CD63 and CD203c expression using several HN allergen concentrations. Depending on their clinical reaction pattern, an oral allergy symptom group (OAS, n = 20), a systemic reaction group (n = 12) and a sensitized group without clinical symptoms (n = 20) were identified. Additionally, 10 non-allergic and non-sensitized individuals served as controls.

Results

CD63 and CD203c expression differed between allergic (OAS and systemic group) and sensitized subjects. The HN concentration required to activate 30% of CD203c⁺ basophils [effective concentration (EC)30] was significantly higher in sensitized versus the allergic group (p = 0.0089). This was more pronounced when the basophil allergen threshold sensitivity (CD-sens) was calculated (CD63: p = 0.018; CD203c: p = 0.009).

Conclusion

Our data indicate that the basophil activation test may provide information to better distinguish between sensitized and allergic subjects if several allergen concentrations are considered. CD203c expression displayed a better discrimination compared to CD63; therefore, its diagnostic value might be superior compared with CD63.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-016-0134-7) contains supplementary material, which is available to authorized users.

Fluvastatin Suppresses Mast Cell and Basophil IgE Responses: Genotype-Dependent Effects

Mast cell (MC)- and basophil-associated inflammatory diseases are a considerable burden to society. A significant portion of patients have symptoms despite standard-of-care therapy. Statins, used to lower serum cholesterol, have immune-modulating activities. We tested the in vitro and in vivo effects of statins on IgE-mediated MC and basophil activation. Fluvastatin showed the most significant inhibitory effects of the six statins tested, suppressing IgE-induced cytokine secretion among mouse MCs and basophils. The effects of fluvastatin were reversed by mevalonic acid or geranylgeranyl pyrophosphatase, and mimicked by geranylgeranyl transferase inhibition. Fluvastatin selectively suppressed key FcεRI signaling pathways, including Akt and ERK. Although MCs and basophils from the C57BL/6J mouse strain were responsive to fluvastatin, those from 129/SvImJ mice were completely resistant. Resistance correlated with fluvastatin-induced upregulation of the statin target HMG-CoA reductase. Human MC cultures from eight donors showed a wide range of fluvastatin responsiveness. These data demonstrate that fluvastatin is a potent suppressor of IgE-mediated MC activation, acting at least partly via blockade of geranyl lipid production downstream of HMG-CoA reductase. Importantly, consideration of statin use for treating MC-associated disease needs to incorporate genetic background effects, which can yield drug resistance.

In vitro diagnosis of immediate IgE-mediated drug hypersensitivity: warnings and (unmet) needs

Immediate drug hypersensitivity reactions (DHR) constitute an important health condition, with serious consequences of inadequate diagnosis. In this article, some of the most important issues related to in vitro diagnosis of IgE-mediated allergies are discussed. In vitro diagnostics will benefit from expanded and novel insights and understandings in drug chemical reactivity, protein binding, biotransformation, degradation, identification of (cross-reactive) drug antigenic determinants, and deeper understanding of sensitization routes. Collective efforts should be undertaken to activate fundamental and clinical investigations.

Mechanisms regulating airway nucleotides

In the respiratory system, extracellular nucleotides and nucleosides serve as signaling molecules for a wide spectrum of biological functions regulating airway defenses against infection and toxic material. Their concentrations are controlled by a complex network of cell surface enzymes named ectonucleotidases. This highly integrated metabolic network combines the activities of three dephosphorylating ectonucleotidases, namely nucleoside triphosphate diphosphohydrolases (NTPDases), nucleotide pyrophosphatase/phosphodiesterases (NPPs) and alkaline phosphatases (APs). Extracellular nucleotides are also inter-converted by the transphosphorylating activities of ecto adenylate kinase (ectoAK) and nucleoside diphosphokinase (NDPK). Different cell types use specific combinations of ectonucleotidases to regulate local concentrations of P2 receptor agonists (ATP, UTP, ADP and UDP). In addition, they provide AMP for the activity of ecto 5'-nucleotidase (ecto 5'-NT; CD73), which produces the P1 receptor agonist: adenosine (ADO). Finally, mechanisms are in place to prevent the accumulation of airway ADO, namely adenosine deaminases and nucleoside transporters. This chapter reviews the properties of each enzyme and transporter, and the current knowledge on their distribution and regulation in the airways.

Reliability of basophil activation test using CD203c expression in diagnosis of pollen allergy

BACKGROUND

CD203c is a basophil surface marker and its expression is rapidly up-regulated after cross-linking of high-affinity immunoglobulin E (IgE) receptor (FcepsilonR1) by an allergen. CD203c basophil activation tests have been studied for the in vitro diagnosis of several allergic conditions. However, there is limited data about its diagnostic usefulness. The optimum allergen concentrations for stimulation and allergen specific cutoff values remain unknown for a number of allergens. This study was designed to investigate the efficacy of basophil activation test via CD203c in the diagnosis of pollen allergy.

METHODS

The CD203c basophil activation was determined in 31 allergic rhinitis patients with pollen allergy and 9 healthy nonatopic controls during the off-season. CD203c expression was evaluated using three-color staining protocol by flow cytometry.

RESULTS

After an in vitro stimulation with grass pollen extract, the CD203c assay clearly discriminated pollen-allergic patients from controls (p < 0.001). A dose-dependent increase in the percentages of CD203c-activated basophils was shown in rhinitis patients with pollen allergy (p < 0.001). The sensitivity and specificity was 100% and optimal cutoff values were 14.05 and 10.05% with 45.1 and 4.5 μg/mL Phl p 5 stimulation, respectively. Although the specificity was also 100%, the sensitivity was 93 and 87% and the cutoff values were 5.40 and 5.35% with 4.5 × 10(-4) and 4.5 × 10(-5) micrograms/mL Phl p 5 stimulation, respectively.

CONCLUSION

The CD203c basophil activation test seems to be a reliable tool in the diagnosis of grass pollen allergy. It could be used when conventional diagnostic tests fail or can not be performed.

Differentially expressed genes in human peripheral blood as potential markers for statin response

There is a considerable inter-individual variation in response to statin therapy and one third of patients do not meet their treatment goals. We aimed to identify differentially expressed genes that might be involved in the effects of statin treatment and to suggest potential markers to guide statin therapy. Forty-six healthy Korean subjects received atorvastatin; their whole-genome expression profiles in peripheral blood were analyzed before and after atorvastatin administration in relation with changes in lipid profiles. The expression patterns of the differentially expressed genes were also compared with the data of familial hypercholesterolemia (FH) patients and controls. Pairwise comparison analyses revealed differentially expressed genes involved in diverse biological processes and molecular functions related with immune responses. Atorvastain mainly affected antigen binding, immune or inflammatory response including interleukin pathways. Similar expression patterns of the genes were observed in patients with FH and controls. The Charcol-Leyden crystal (CLC), CCR2, CX3CR1, LRRN3, FOS, LDLR, HLA-DRB1, ERMN, and TCN1 genes were significantly associated with cholesterol levels or statin response. Interestingly, the CLC gene, which was significantly altered by atorvastatin administration and differentially expressed between FH patients and controls, showed much bigger change in high-responsive group than in low-responsive group. We identified differentially expressed genes that might be involved in mechanisms underlying the known pleiotropic effects of atorvastatin, baseline cholesterol levels, and drug response. Our findings suggest CLC as a new candidate marker for statin response, and further validation is needed.

Flow-assisted allergy diagnosis: current applications and future perspectives

Physicians predominantly rely upon quantification of serum-specific immunoglobulin E (IgE) and/or skin test to confirm clinically suspected IgE-mediated allergy. However, for various reasons, identification of the offending allergen(s) and potentially cross-reactive structures is not always straightforward. Flow-assisted allergy diagnosis relies upon quantification of alterations in the expression of particular basophilic activation markers. Actually, upon challenge with a specific allergen, basophils not only secrete quantifiable bioactive mediators but also upregulate the expression of different markers which can be detected efficiently by flow cytometry using specific monoclonal antibodies. Currently, the technique has been applied in the investigation of IgE-mediated allergy caused by classical inhalant allergens, food, Hevea latex, hymenoptera venoms and drugs. It is also appreciated; the technique proves valuable in the diagnosis of non-IgE-mediated (anaphylactoid) reactions such drug hypersensitivity and the detection of autoantibodies in certain forms of chronic urticaria. This review will not address immunologic features, characteristics and general pitfalls of flow-assisted analysis of in vitro-activated basophils as summarized elsewhere. After a recapitulation of the principles and some specific technical issues of flow-assisted analysis of in vitro-activated basophils, we principally focus on the current clinical and research applications of the basophil activation tests. Personal experience of both research groups is provided, where appropriate. Finally, a viewpoint on how the field might evolve in the following years is provided.

Effects of various statins on cytokine-dependent growth and IgE-dependent release of histamine in human mast cells

BACKGROUND

Statins are inhibitors of hydroxymethylglutaryl coenzyme A (HMG CoA) reductase, a key enzyme in mevalonic acid (MVA)-dependent signaling. Recent data suggest that statins exhibit profound inhibitory effects on growth and function of various immune cells. In the present study, we examined the in vitro effects of five different statins on primary human mast cells (MCs), MC progenitors, and the human MC line HMC-1.

METHODS

Histamine release experiments were conducted on isolated MCs using statins and an anti-immunoglobulin E (IgE) antibody. Culture experiments were performed with stem cell factor (SCF) and interleukin (IL)-6, and cord blood-derived progenitors.

RESULTS

Preincubation of primary lung MCs with cerivastatin or atorvastatin (1-50 microM) for 24 h resulted in inhibition of anti-IgE-induced release of histamine. The effects of both statins were dose-dependent. Moreover, both statins, and to a lesser degree lovastatin, were found to inhibit the SCF-induced differentiation of MCs from their progenitors. The other statins tested (simvastatin, pravastatin) did not affect mediator release or growth of MCs.

CONCLUSIONS

Cerivastatin and atorvastatin act as inhibitors of growth and function of human MCs.

Effects of simvastatin withdrawal on serum matrix metalloproteinases in hypercholesterolaemic patients

BACKGROUND

Serum matrix metalloproteinase (MMP) levels have been related to clinical outcomes in patients with coronary artery disease. Though statin treatment might reduce serum MMPs the change of levels after statin withdrawal remains obscure.

MATERIALS AND METHOD

Sixty-one consecutive hypercholesterolaemic patients whose lipid profiles had been well controlled by regular simvastatin (20 mg day(-1)) treatment for more than 6 months were enrolled. Statin was discontinued after their lipid profiles reached the treatment goal of the ATP-III guideline. The lipid profiles, serum MMP-2, MMP-3 and MMP-9, tissue inhibitor of MMP and highly sensitive C-reactive protein (hsCRP) levels were measured on the day of simvastatin withdrawal and 120 days later. A further 50 hyperlipidaemia patients who had never received statin treatment (positive control group) and 28 healthy patients with normal lipid profiles (negative control group) were also studied as control groups.

RESULTS

While the lipid profiles had been normalized, the levels of serum inflammatory markers were still higher in hypercholesterolaemic patients than in the healthy subjects. Up to 120 days after statin withdrawal there was no coronary event, but the lipid profiles and serum hsCRP levels had significantly rebounded in study patients. However, serum MMP-2 and MMP-9 levels remained unchanged and the MMP-3 level was even further reduced after statin withdrawal (115.04 +/- 84.54 vs. 92.71 +/- 66.71 ng mL(-1), P = 0.022). Moreover, the amplitudes of variation (%) of each parameter including MMPs, TIMP, hsCRP and lipid profiles after statin withdrawal were inversely correlated to their respective baseline levels before withdrawal (r = -0.702 to -0.284; P < 0.005).

CONCLUSIONS

The effects of short-term discontinuation of statin were different on serum hsCRP and MMPs levels in hypercholesterolaemic patients. While lipid profiles and serum hsCRP level had rebounded the serum MMPs levels were still unchanged, or even reduced, suggesting the prolonged effect of statin treatment, especially on serum MMP-3 level up to 120 days after simvastatin withdrawal. Further work is required to clarify the situation both in terms of these serum markers and clinical effects.

Histamine release during adult cardiopulmonary bypass

Histamine, an inflammatory mediator in its own right, may also be a marker for a more widespread systemic inflammatory process. In this study we have examined variations in plasma histamine concentrations produced during the course of cardiac surgery involving cardiopulmonary bypass, the relationship between these variations and intra-operative events. By assays of serum tryptase and CD-63 expression we have also attempted to identify the source of histamine. Histamine concentrations that were significantly raised from baseline level were demonstrated. These were elevated from the time of aortic cross-clamping and continued to be raised for 24 h postoperatively (p < 0.00625). This was associated with an increase in CD-63 expression (p < 0.025) (but not an increase in tryptase concentration) following aortic cross-clamping and protamine administration, suggesting that basophils are the source of histamine. 41% of patients had arrhythmias in the post bypass period. The rise in histamine levels was not related to the incidence of cardiac arrhythmias.

Identification of CD13, CD107a, and CD164 as novel basophil-activation markers and dissection of two response patterns in time kinetics of IgE-dependent upregulation

Using two-colour flow cytometry >200 antibodies submitted to the 8th International Workshop of Human Leukocyte Differentiation Antigens (HLDA8) have been analyzed for their reactivity with resting and activated CD203c+ basophils. Four antibodies either non-reactive or weakly reactive with resting basophils exhibited an increased reactivity with basophils activated by anti-IgE-mediated cross-linking of the high affinity IgE receptor (FceRI). These include antibodies against CD164 (WS-80160, clone N6B6 and WS-80162, clone 67D2), as well as two reagents with previously unknown specificities that were identified as CD13 (WS-80274, clone A8) and CD107a (WS-80280, clone E63-880). The activation patterns followed either the "CD203c-like" or "CD63-like" activation profile. The CD203c profile is characterized by a rapid and significant upregulation (of CD13, CD164, and CD203c), reaching maximum levels after 5-15 min of stimulation. The Phosphoinositide-3-kinase (PI3K)-specific inhibitor Wortmannin inhibited the upregulation of these markers whereas 12-O-tetradecanoyl-phorbol-13-acetate (TPA) induced a rapid and FceRI-independent upregulation within 1-2 min. In the CD63 profile, maximum upregulation (of CD63 and CD107a) was detected only after 20-40 min, and upregulation by TPA reached maximum levels after 60 min. In summary, our data identify CD13, CD107a, and CD164 as novel basophil-activation antigens. Based on time kinetics of upregulation, we hypothesize that molecules of the "CD203c group" and the "CD63 group" are linked to two different mechanisms of basophil activation.

In vitro allergy diagnosis: should we follow the flow?

During the last 5 years, an increasing number of studies have demonstrated that flow cytometric quantification of in vitro basophil activation can be a quite performant and reliable tool to measure IgE-dependent allergen-specific responses in allergic patients. So far, most assays have used CD63 as a basophil activation marker and native allergen extracts for stimulation. However, other basophil markers and recombinant allergens have recently been introduced. The technique has been applied for the diagnosis of allergy to pollen, house dust mite, food, natural rubber latex, hymenoptera venom and drugs. In addition, the technique has proven to be useful in non-IgE-mediated reactions such as hypersensitivity to drugs as well as detection of auto-antibodies in chronic urticaria. This review will focus on some specific issues: (1) principles of flow cytometric analysis of in vitro-activated basophils, (2) general technical aspects of the technique (including passive sensitization), (3) clinical applications and (4) recommendations for further development and evaluation of the technique.

Noncholesterol-lowering effects of statins

Statins, 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, inhibit the rate-limiting enzyme in cholesterol synthesis and lead to a significant reduction of plasma lipid concentrations. As a clear correlation exists between serum cholesterol and cardiovascular risk, statins have become increasingly important in current preventive medicine. Studies prompted by the extraordinary benefits afforded by these drugs have reported minimal changes in the vasculature of hypercholesterolemic patients when compared with clinical benefits and have led to further investigations to determine the underlying reasons for these clinical benefits. The purpose of this review is to present the wide array of systems that HMG-CoA reductase inhibitors are known to influence, which range from adverse events due to coronary artery disease, stroke risk, platelet function, endothelial function, and inflammatory effects to intracellular signaling pathways that control vascular cell migration, proliferation, and differentiation.