Involvement of levels of Toll like receptor-4 in monocytes,CD4 + T-lymphocyte subsets,and cytokines in patients with immune thrombocytopenic purpura

Introduction

Toll-like receptors have been found to be associated with immune-mediated diseases but it is still not clear whether they play a role in immune thrombocytopenic purpura (ITP), especially TLR4. CD4 + T-lymphocyte abnormalities, including Th17, Th1, Th2, and regulator T cell (Treg), are considered important in ITP. There have been few studies regarding the expression of TLR4 and the relationships between TLR4 and Th17 levels in ITP.

Materials and Methods

In this study, we evaluated the expression of TLR4 in monocytes, the plasma concentrations of IL-23, IL-17 and the profiles of Th17, Th1, Th2 cells in 70 patients with ITP and 31 healthy controls. In addition, we evaluated IL-2 and Treg cells in 46 cases of 70 patients with ITP and the same 31 controls.

Results

Higher levels of TLR4 expression, higher relative numbers of Th17 and Th1 cells and lower levels of Treg cells were observed in patients when compared with controls (p = 0.001 for TLR4; p < 0.001 for Th17; p = 0.014 for Th1; p = 0.001 for Treg). The levels of IL-23 and IL-2 were increased (p = 0.022 for IL-23; p = 0.025 for IL-2), the relative levels of Th2 and concentrations of IL-17 were similar across both groups (p = 0.446 for Th2; p = 0.316 for IL-17). A significant negative correlation was observed between levels of TLR4 and Treg(r = -0.544, p < 0.001), but a significantly positive correlation was observed between IL-2 and IL-23 concentration in patients (r = 0.441, p = 0.004). Neither the correlation between TLR4 and the other CD4⁺ T cells and cytokines nor the correlation between the three cytokines and CD4+ T cells was found to be statistically significant.

Conclusions

Our data showed that TLR4, CD4 + T cells (Th1, Th17 and Treg cells) and related cytokines (IL-23, IL-2) may take part in the pathogenesis of ITP. TLR4 may play a role through the TLR4-cytokine-CD4+ T lymphocyte cell pathway.     

Regulatory T cells increased while IL-1β decreased during antidepressant therapy

Background

Regulatory T cells (Tregs, CD4⁺CD25^hi) are specialized in steering the immune response and cytokine release to maintain tolerance to self-antigens. As cytokines such as interleukin (IL)-1β, IL-6 and interferon (IFN)-α have been shown to be involved in the pathophysiology of depression and cytokine levels have been shown to change during successful antidepressant treatment, we tested the involvement CD4⁺CD25^hi Tregs in these immunological processes during antidepressant therapy.

Methods

16 patients suffering from a depressive episode were included into the study and treated with antidepressants according to their doctor’s choice. Blood samples were collected during the first week after admission and after 6 weeks of treatment. Therein, we determined plasma levels of IL-1β, and measured IL-1β, IL-6 and IFN-α levels in the stimulated blood by performing a whole blood assay. We distinguished lymphocytes and identified CD4⁺CD25^hi Tregs by multiparameter flow cytometry. The psychopathological status was assessed using the Hamilton Depression Rating Scale (HAMD-21).

Results

HAMD-21 score, IL-1β serum levels as well as LPS-stimulated IL-1β and IL-6 production had decreased significantly at the end of treatment. In contrast, the amount of CD4⁺CD25^hi cells increased significantly from 2.74% ± 0.88 (mean value ± standard deviation) to 3.54% ± 1.21; p = 0.007. No significant changes in virus-induced IFN-α production was observed.

Conclusions

The increase in CD4⁺CD25^hi Tregs during antidepressant therapy may be the reason for the decrease in cytokine production and the recovery from depression.     

Interictal alterations of cytokines and leukocytes in patients with active epilepsy

Background

Involvement of the innate immune system in the pathogenesis of epilepsies has been suggested but possible interactions between the immune system and human epilepsy remain unclear. We analyzed the interictal immuno-phenotype of leukocyte subsets and proinflammatory cytokine profiles in epileptic patients and correlated them with the epilepsy syndrome.

Methods

101 patients with active focal or generalized epilepsy were prospectively included and compared to 36 healthy controls. Immuno-phenotype of leukocyte subsets and cytokines IL-1β, IL-6 and tnfα were measured in peripheral blood. Multivariate analyses were performed to test group differences.

Results

As compared to controls, the patients showed an elevated percentage of monocytes (18.06 ± 7.08% vs. 12.68 ± 4.55%, p < 0.001), NK cells (14.88 ± 7.08% vs. 11.43 ± 5.41%, p = 0.019) and IL-6 concentration (3.33 ± 3.11 pg/ml vs. 1.5 ± 1.36 pg/ml, p = 0.002). This remained true when focal epilepsies or generalized epilepsies were compared separately to controls but only focal epilepsies showed additionally a decrease in B lymphocyts (8.16 ± 3.76% vs. 11.54 ± 4.2%, p < 0.001). Treatment with lamotrigine was associated with a higher percentage of B lymphocytes and valproate with an increased percentage of CD4⁺ T lymphocytes. Therapy with levetiracetam showed a trend towards decreased CD8⁺ T cell counts. No significant differences were seen between focal and generalized epilepsies and between temporal and extratemporal lobe epilepsies.

Conclusion

Patients with active epilepsy revealed interictal alterations of the immune system which varied among specific syndromes and were influenced by antiepileptic drug treatment.     

Peripheral leukocyte profile in people with temporal lobe epilepsy reflects the associated proinflammatory state

IntroductionMarkers of low-grade peripheral inflammation have been reported amongst people with epilepsy. The mechanisms underlying this phenomenon are unknown. We attempted to characterize peripheral immune cells and their activation status in people with temporal lobe epilepsy (TLE) and healthy controls.Methods and resultsTwenty people with TLE and 19 controls were recruited, and peripheral blood lymphocyte and monocyte subsets evaluated ex vivo by multi-color flow cytometry. People with TLE had higher expression of HLA-DR, CD69, CTLA-4, CD25, IL-23R, IFN-γ, TNF and IL-17 in CD4⁺ lymphocytes than controls. Granzyme A, CTLA-4, IL-23R and IL-17 expression was also elevated in CD8⁺ T cells from people with TLE. Frequency of HLA-DR in CD19⁺ B cells and regulatory T cells CD4⁺CD25⁺Foxp3⁺ producing IL-10 was higher in TLE when compared with controls. A negative correlation between CD4⁺ expressing co-stimulatory molecules (CD69, CD25 and CTLA-4) with age at onset of seizures was found. The frequency of CD4⁺CD25⁺Foxp3⁺ cells was also positively correlated with age at onset of seizures.ConclusionImmune cells of people with TLE show an activation profile, mainly in effector T cells, in line with the low-grade peripheral inflammation.     

Direct demonstration of the infiltration of murine central nervous system by Pgp-1/CD44 CD45RB CD4 T cells that induce experimental allergic encephalomyelitis

In experimental allergic encephalomyelitis (EAE), autoimmune T cells infiltrate the central nervous system (CNS) and initiate demyelinating pathology. We have used flow cytometry to directly analyse the migration to the CNS of MBP-reactive CD4⁺ T cells labelled with a lipophilic fluorescent dye (PKH2), in SJL/J mice with passively transferred EAE. Labelled cells constituted about 45% of the CNS CD4⁺ population at the time of EAE onset. Almost all (>90%) of the PKH2-labelled CD4⁺ T cells from EAE CNS were blasts and were α/β T cell receptor (TCR)⁺, CD44(Pgp-1)^high, and the majority were CD45RB^low. By contrast, most PKH2-labelled CD4⁺ T cells in lymph nodes, although CD44^high, were CD45RB^high cells. The cells that were transferred to induce EAE were essentially similar to antigen-primed lymph node cell populations, containing less than 15% CD44^high cells, and most of them were CD45RB^high. The CD44^high CD45RB^low phenotype is characteristic of memory/effector T cells that have been activated by antigen recognition. The difference in CD45RB expression between CNS and LN could therefore reflect differential exposure and/or response to antigen. Consistent with this, PKH2-labelled CD4⁺ cells isolated from the CNS were responsive to MBP in vitro, whereas PKH2⁺ CD4⁺ cells from lymph nodes showed almost undetectable responses. In control experiments in which ovalbumin (OVA)-reactive T cells were transferred, a small number of fluorescent-labelled CD4⁺ T cells were also detected in CNS, but there were very few blasts, and these remained CD45RB^high. These results argue for induction of the memory/effector phenotype of CD4⁺ cells, their selective retention in the CNS, as a consequence of antigen recognition.     

Interleukin-17-secreting T cells in neuromyelitis optica and multiple sclerosis during relapse

Growing evidence suggests that interleukin (IL)-17 and IL-17-secreting CD4⁺T (Th17) cells are involved in the pathogenic mechanisms of multiple sclerosis (MS). IL-17-secreting CD8⁺T cells were recently identified as a novel subset of CD8⁺T cells. We aimed to analyze the role of Th17 and IL-17 secreting CD8⁺T cells in the pathogenesis of neuromyelitis optica (NMO) as well as MS. Fourteen patients with NMO, 20 with MS and 16 control participants (CTL) were enrolled between November 2008 and December 2009. The proportion of Th17 cells and IL-17 secreting CD8⁺T cells were counted using flow cytometry, and serum levels of IL-6, IL-17, IL-21, IL-23, and transforming growth factor-beta (TGF-β) were measured by enzyme-linked immunosorbent assay. Patients with NMO had a larger proportion of Th17 cells than patients with MS (3.72% versus [vs.] 2.58%, p = 0.02) and CTL (3.72% vs. 1.36%, p < 0.001). The proportion of Th17 cells in patients with MS was also markedly higher than in the CTL (2.58% vs. 1.36%, p < 0.001). IL-17-secreting CD8⁺T cell counts in NMO patients were markedly higher than in MS patients (1.61% vs. 1.09%, p = 0.036) and CTLs (1.61% vs. 0.58%, p < 0.001). The proportion of IL-17-secreting CD8⁺T cells in MS patients was also higher than in CTLs (1.09% vs. 0.58%, p = 0.002). Serum IL-17 and IL-23 levels were increased in patients with NMO and MS, while serum IL-21 concentration was higher only in NMO patients compared to CTL. We concluded that Th17 cells were highly activated in patients with NMO. IL-17-secreting CD8⁺T cells were increased in patients with NMO and MS during relapse and have an important role in the pathological mechanism of NMO and MS.     

Infiltration of Th1 and Th17 cells and activation of microglia in the CNS during the course of experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is a mouse model for multiple sclerosis, where disease is mediated by autoantigen-specific T cells. Although there is evidence linking CD4⁺ T cells that secrete IL-17, termed Th17 cells, and IFN-γ-secreting Th1 cells with the pathogenesis of EAE, the precise contribution of these T cell subtypes or their associated cytokines is still unclear. We have investigated the infiltration of CD4⁺ T cells that secrete IFN-γ, IL-17 or both cytokines into CNS during development of EAE and have examined the role of T cells in microglial activation. Our findings demonstrate that Th17 cells and CD4⁺ T cells that produce both IFN-γ and IL-17, which we have called Th1/Th17 cells, infiltrate the brain prior to the development of clinical symptoms of EAE and that this coincides with activation of CD11b⁺ microglia and local production of IL-1β, TNF-α and IL-6 in the CNS. In contrast, significant infiltration of Th1 cells was only detected after the development of clinical disease. Co-culture experiments, using mixed glia and MOG-specific T cells, revealed that T cells that secreted IFN-γ and IL-17 were potent activators of pro-inflammatory cytokines but T cells that secrete IFN-γ, but not IL-17, were less effective. In contrast both Th1 and Th1/Th17 cells enhanced MHC-class II and co-stimulatory molecule expression on microglia. Our findings suggest that T cells which secrete IL-17 or IL-17 and IFN-γ infiltrate the CNS prior to the onset of clinical symptoms of EAE, where they may mediate CNS inflammation, in part, through microglial activation.     

Soluble urokinase plasminogen activator receptor in patients with abdominal aortic aneurysm

Introduction

In the present study we investigated the impact of soluble urokinase plasminogen activator receptor (suPAR) as a biomarker in patients with abdominal aortic aneurysm (AAA) in relation to conventional inflammatory markers, aneurysm size, and rupture.

Methods

suPAR and conventional inflammatory markers were measured in 119 patients with AAA and 36 controls without aneurysm matched by age, gender and smoking habit.

Results

The results support earlier studies suggesting a state of activated inflammatory response in patients with nonruptured AAA as expressed by elevated CRP and IL-6 compared with the controls. In contrast, suPAR showed similar levels in patients with nonruptured AAA compared with the controls. Unexpectedly, all follow-up patients (n = 16) have significant (p < 0.001) elevated suPAR levels three years postoperatively compared preoperatively.

Conclusions

suPAR does not seem to be a useful biomarker in the AAA disease. The role of the postoperative elevation of suPAR needs to be further elucidated.     

Glucocorticoids increase CD4CD25 cell percentage and Foxp3 expression in patients with multiple sclerosis

Objectives – To determine whether percentages of CD4⁺CD25^high T cells (a group of regulatory T cells, Treg) differ in patients with multiple sclerosis (MS) in relapse vs remission after glucocorticoid treatment and whether treatment for relapses changes Treg population and the expression of Foxp3, a key Treg‐associated molecule. Materials and methods – Peripheral blood mononuclear cells (PBMC) were obtained from 20 patients with MS during relapse, just before and 2 days after starting steroid treatment (i.v. methylprednisolone 1 g/day for 3 days) and then 6 weeks after treatment. CD4⁺CD25^hi cells were analysed by using flow cytometry. Cytokines were measured by using an ELISA and Foxp3, CD3 and CD25 expression by using quantitative real‐time PCR. Results – The percentage of CD4⁺CD25^hi cells, plasma IL‐10 and Foxp3/CD3 ratio increased 48 h after methylprednisolone initiation and returned to baseline values by 6 weeks post‐treatment. Conclusions – Results suggest that glucocorticoids increase Treg cell functional molecules and percentages. This may be a mechanism whereby steroids expedite recovery from MS relapses.     

Mechanism of action of glatiramer acetate in treatment of multiple sclerosis

Glatiramer acetate (GA) (Copolymer-1, Copaxone, Teva, Israel, YEAK) is a polypeptide-based therapy approved for the treatment of relapsing-remitting multiple sclerosis. Most investigations have attributed the immunomodulatory effect of GAs to its capability to alter T-cell differentiation. Specifically, GA treatment is believed to promote development of Th2-polarized GA-reactive CD4⁺ T-cells, which may dampen neighboring inflammation within the central nervous system. Recent reports indicate that the deficiency in CD4⁺CD25⁺FoxP3⁺ regulatory T-cells in multiple sclerosis is restored by GA treatment. GA also exerts immunomodulatory activity on antigen presenting cells, which participate in innate immune responses. These new findings represent a plausible explanation for GA-mediated T-cell immune modulation and may provide useful insight for the development of new and more effective treatment options for multiple sclerosis.     

Sex-specific cortisol levels in bipolar disorder and schizophrenia during mental challenge--relationship to clinical characteristics and medication

Objective

Our objective was to examine the cortisol release during a mental challenge in severe mental disorders versus healthy controls (HC), analyzing effects of sex, clinical characteristics and medication, and comparing Bipolar Disorder (BD) to Schizophrenia (SCZ).

Methods

Patients with BD and SCZ (n = 151) were recruited from a catchment area. HC (n = 98) were randomly selected from the same area. Salivary samples were collected before and after a mental challenge and cortisol levels determined.

Results

During the challenge there was an interaction between group and sex (P = 0.015) with male patients having a blunted cortisol release compared to male HC (P = 0.037). Cortisol change did not differ significantly between BD and SCZ. In all patients, the cortisol change correlated with number of psychotic episodes (r = − 0.23, P = 0.025), and in females patients, with number of depressive episodes (r = − 0.33, P = 0.015). Patients using antidepressants had a greater cortisol release during challenge than those not using antidepressants (P = 0.043).

Conclusions

Male patients with severe mental disorders seem to have a uniform abnormal cortisol release during mental challenges which associates with clinical course, and with beneficial effects of antidepressants.     

Lymphokine mRNA expression in the spinal cords of Lewis rats with experimental autoimmune encephalomyelitis is associated with a host recruited CD45R hi/CD4 population during recovery

To evaluate CD4⁺ T cell subpopulations involved in the induction and recovery from experimental autoimmune encephalomyelitis (EAE), the CD45R phenotype and lymphokine mRNA profile was evaluated for encephalitogenic CD4⁺ T cell lines in vitro and compared to CD4^* T cells islated from the spinal cord of Lewis rats with EAE were > 90% of the myelin basic protein (MBP)-specific T cell lines and clones that adoptively transferred EAE were > 90% CD4⁺ and > 90% CD45R lo. A time course of EAE disease progression was monitored as a function of the percentage of CD45R hi/CD4⁺ T cells isolated from the spinal cords of diseased animals. The majority of CD4⁺ T cells found in the central nervous system during the early phase of passive EAE were CD45R lo (the same as the encephalitogenic lines/clones). A large increase of the CD45R hi/CD4⁺ T cells (up to 45%) was observed during the peak and recovery phases of EAE. Lymphokine mRNA production was analyzed from antigen-stimulated MBP-specific lines, and from spinal cord lymphocytes isolated from rats with EAE. The BP-specific lines produced Th1 lymphokines (IL-2, IFN-γ, and TNF-α), while the spinal cord lymphocytes produced the same Th1 lymphokines as well as IL-4 and IL-10. The CD45R hi/CD4⁺ T cells isolated from the spinal cords were larger and expressed more lymphokine RNA per cell than the CD45R lo/CD4⁺ T cells. The encephalitogenic cells (CD45R hi/CD4⁺ T detected in the spinal cords of rats with a fluorescent dye and by allelic transfers and all of the CD45R hi/CD4⁺ lymphocytes found in the spinal cells were found to be host recruited. Thus it appears that the CD45R hi/CD4⁺ lymphocytes found in the spinal cord represent a host-recruited, activated cellular infiltrate that increased in number in the recovery phase of EAE and synthesized both Th1 and Th2 lymphokines.     

Effect of IFN-ß therapy on the frequency and function of CD4+CD25+ regulatory T cells and Foxp3 gene expression in relapsing–remitting multiple sclerosis (RRMS): A preliminary study

Interferon-ß (IFN-ß) is an immunomodulatory drug of choice to control relapsing–remitting multiple sclerosis (RR-MS), although its function is still unclear. A reduced suppressive function of CD4⁺CD25⁺ regulatory T cells (T_reg) has been shown in RR-MS patients. In this study, to understand the effect of IFN-ß on CD4⁺CD25⁺ regulatory T cells, we analyzed the frequency and function of these cells and Foxp3 gene expression before and after treatment.We evaluated the frequency and function of CD4⁺CD25⁺Foxp3⁺ regulatory T cells by flow cytometry and co-culture inhibition test respectively and gene expression of Foxp3 by real-time PCR in a longitudinal follow-up study in 18 relapsing–remitting MS patients. Our data revealed that IFN-ß significantly improved frequency and suppressive function of T_reg cells (P < 0.05) without any significant effect on gene expression of Foxp3 after 6 months. The results of the present study indicate that IFN-ß therapy in some of patients with RR-MS may restore function of regulatory T cells and control the unchecked immune cascade activity. Larger longitudinal studies on more MS patients are required to confirm our findings.     

Gonadectomy of male BALB/c mice increases Tim-3+ alternatively activated M2 macrophages,Tim-3+ T cells,Th2 cells and Treg in the heart during acute coxsackievirus-induced myocarditis

The incidence of cardiovascular disease, including inflammatory heart diseases like myocarditis, is increased in men. Similarly, male BALB/c mice infected with coxsackievirus B3 (CVB3) develop more severe acute inflammation in the heart compared to females. To better understand the effect of male sex hormones on cardiac inflammation, we gonadectomized (Gdx) male BALB/c mice and examined acute CVB3-induced myocarditis compared to sham controls. Viral replication in the heart was not significantly altered between Gdx and sham mice. However, gonadectomy significantly reduced testosterone levels and inflammation in the heart. FACS analysis of cell populations isolated from the heart revealed that CD11b⁺ cells were significantly reduced in Gdx males. However, a GR1⁺F4/80⁺ subset of CD11b⁺ cells was significantly increased. Because this subset also expressed the interleukin (IL)-4R and IL-10, we refer to these cells as “alternatively activated” or M2 macrophages. A greater percentage of M2 macrophages in Gdx males expressed the inhibitory receptor Tim-3, while fewer expressed IL-1β and IL-10. Only M2 macrophages upregulated TLR4 and Tim-3, whereas GR1^?IL-4R^lo macrophages did not. Additionally, IL-4⁺CD4⁺ Th2 cells, Foxp3⁺ regulatory T (Treg) cells and Tim-3⁺CD4⁺ T cells were significantly increased in the heart following Gdx. Thus, we report for the first time that the inhibitory receptor Tim-3 is expressed on M2 macrophages. Our findings show that sex hormones and/or other mediators released from the testes inhibit anti-inflammatory populations in the heart including Tim-3⁺ M2, Tim-3⁺CD4⁺ T cells, Th2 and Treg resulting in more severe acute cardiac inflammation in males following CVB3 infection.     

Dopamine favors expansion of glucocorticoid-resistant IL-17-producing T cells in multiple sclerosis

Dopamine (DA) is a neurotransmitter produced mainly in the central nervous system (CNS) that has immunomodulatory actions on T cells. As the multiple sclerosis (MS) has long been regarded as an autoimmune disease of CNS mediated by T cells, the objective of this study was to evaluate the impact of DA on in vitro functional status of T cells from relapsing–remitting (RR)–MS patients. Peripheral T-cells from RR–MS patients were activated by mitogens and cell proliferation and cytokine production were assayed by [³H]-thymidine uptake and ELISA, respectively. Our results demonstrated that DA enhanced in vitro T cell proliferation and Th17-related cytokines in MS-derived cell cultures. In addition, this catecholamine reduced Treg-related cytokines (IL-10 and TGF-β) release by activated CD4⁺ T cells. These DA-induced effects on T cells were mainly dependent on IL-6 production by both polyclonally-activated CD4⁺ T cells and LPS-stimulated monocytes. Furthermore, the production of IL-17 and IL-6 by MS-derived T cells was directly related with neurological disability (EDSS score), and the release of these cytokines was less sensitive to glucocorticoid inhibition in MS patients than in control group, mainly after DA addition. In conclusion, our data suggest that DA amplifies glucocorticoid-resistant Th17 phenotype in MS patients, and this phenomenon could be, at least in part, due to its ability to induce IL-6 production by monocytes and CD4⁺ T cells.     

Relationship between a hopeful attitude and cellular immunity in patients with breast cancer

Objectives

To evaluate the relationship between hopefulness and immune function in patients with breast cancer.

Methods

A total of 196 patients with breast cancer were enrolled. The subjects were divided into two groups using the abbreviated version of the seven-item Beck Hopelessness Scale (BHS-7). Subsets of circulating lymphocytes were assessed using flow cytometry: CD3⁺, CD4⁺, CD8⁺, CD19⁺ and CD56⁺. The Beck Depression Inventory (BDI), Montgomery-Asberg Depression Rating Scale (MADRS) and EORTC QLQ-C30 were administered.

Results

A total of 104 patients (53.6%) showed a hopeful attitude, with a score of 0 on the BHS-7. Scores on the MADRS and BDI were significantly higher in the nonhopeful group, whereas global and total functioning scores on the EORTC QLQ-C-30 were significantly higher in the hopeful group. The hopeful group showed significantly higher CD8⁺ T-cell percentage and counts and significantly lower CD4⁺ T-cell percentage and CD19⁺ B-cell percentage and counts compared with the nonhopeful group. All statistically significant differences between the two groups were maintained after adjusting for age and scores on the BDI and EORTC QLQ-C-30 as covariates, except for CD 19⁺ cell counts.

Conclusion

The results suggest that hopefulness may be associated with immunity in patients with breast cancer, independent of depression and quality of life.     

CD4CD25 regulatory T cell in childhood ocular myasthenia gravis

Dysfunction of CD4⁺CD25⁺ regulatory T cell (Treg) has been demonstrated to play an important role in the development of autoimmune myasthenia gravis. This T cell subset, which has potent regulatory properties against immune response, has been reported to have a numerical or functional defect in patients with myasthenia gravis. We examined various T cell subsets, including CD4⁺CD25⁺Treg in peripheral blood mononuclear cells using flow cytometry in a pediatric patient suffering from ocular myasthenia gravis. Contrary to previous reports, the percentage of CD4⁺CD25⁺Treg in peripheral blood decreased significantly after successful treatment with prednisolone. This discrepancy could result from diversity within the immunopathogenesis of myasthenia gravis and may underpin a particular subgroup of myasthenia gravis seen in the East-Asian pediatric population.     

Platelet activation in patients with peripheral vascular disease: reproducibility and comparability of platelet markers

Background

Many markers of platelet activation have been described but their reproducibility and comparability in patient populations are poorly defined.

Objectives

We sought to compare markers of platelet and monocyte activation with platelet-monocyte aggregates, a proposed gold standard of in vivo platelet activation, and assess their reproducibility in patients with peripheral arterial disease: a population with substantial platelet activation, inflammation and risk of thrombotic events.

Patients/Methods

Thirty patients with peripheral vascular disease attended on two occasions to permit within-day and between-day comparisons. In vivo platelet and monocyte activation were determined by flow-cytometric quantification of platelet-monocyte aggregation, platelet surface expression of P-selectin and CD40L, platelet-derived microparticles, and monocyte surface expression of CD40 and CD11b. Plasma concentrations of platelet-derived microparticles, soluble P-selectin and CD40L were measured by enzyme-linked immunosorbant assays.

Results

Platelet-monocyte aggregation (36.7 ± 7.86%), and platelet surface expression of P-selectin (5.8 ± 1.65%) and CD40L (3.3 ± 1.45%) demonstrated comparable within-day (mean difference ± co-efficient of reproducibility; 0.9 ± 15.4%, 0.21 ± 1.65% and 0.2 ± 2.8% respectively) and between-day reproducibility (2.0 ± 12.4%, 0.10 ± 2.25% and 0.9 ± 6.4% respectively). Platelet-monocyte aggregates correlated well with other platelet (r = 0.30-0.50, P < 0.02) and monocyte (r = 0.27-0.47, P < 0.03) activation markers. Flow cytometric and assay quantified platelet-derived microparticles showed poorer reproducibility (co-efficient of reproducibility > 40).

Conclusions

In patients with peripheral arterial disease, measurements of platelet-monocyte aggregates have good reproducibility and consistently reflect other markers of platelet and monocyte activation.     

Anti-prothrombin antibodies are associated with thrombosis in children

Introduction

This investigation aimed to evaluate thrombotic risk factors in children, with special reference to autoantibodies against prothrombin and protein S.

Materials and methods

We studied 57 consecutive Swedish children and adolescents referred with a radiologically confirmed acute thrombotic event. Clinical data were collected and a thrombophilia investigation was performed, including analysis of autoantibodies against protein S (anti-PS) and prothrombin (anti-PT). The anti-PS and anti-PT autoantibodies were also investigated in sera from 47 healthy controls. Detection of autoantibodies was performed by quantitative enzyme-linked immunosorbent assays.

Results

Results for anti-PT antibodies were positive in 21% (12/57) of the patients and 2.1% (1/47) of the controls (OR 12.0, 95% CI 1.7-534; p = 0.005). Seven percent (4/57) of the patients and 2.1% (1/47) of the controls were positive for anti-PS antibodies (OR 3.4, 95% CI 0.3-174; p > 0.30). The FV G1691A mutation was found in 25% (14/57), and 44% (25/57) had 2 or more prothrombotic risk factors. Sixty percent (34/57) of the thrombosis patients were female. Peaks in frequency of thromboembolic events were found in the neonatal and the adolescent periods. Fifty-three percent (30/57) had thrombosis in the lower venous system. Associated clinical conditions occurred in 91% (52/57): systemic illness in 31% (18/57), infections in 26% (15/57), and oral contraceptive use in 25% (14/57). Four percent (2/57) had no apparent clinical or prothrombotic risk factors.

Conclusions

This study suggests that anti-PT autoantibodies may be common risk factors for thrombosis in children, and it confirms the multifactorial nature of pediatric thrombosis.