Developmental changes in soluble CD40 ligand

Biomarkers detected in cord blood predict vaccine responses in young infants

Introduction

Factors influencing vaccine immune priming in the first year of life involve both innate and adaptive immunity but there are gaps in understanding how these factors sustain vaccine antibody levels in healthy infants. The hypothesis was that bioprofiles associated with B cell survival best predict sustained vaccine IgG levels at one year.

Methods

Longitudinal study of plasma bioprofiles in 82 term, healthy infants, who received standard recommended immunizations in the United States, with changes in 15 plasma biomarker concentrations and B cell subsets associated with germinal center development monitored at birth, soon after completion of the initial vaccine series at 6 months, and prior to the 12-month vaccinations. Post vaccination antibody IgG levels to Bordetella pertussis, tetanus toxoid, and conjugated Haemophilus influenzae type B (HiB) were outcome measures.

Results

Using a least absolute shrinkage and selection operator (lasso) regression model, cord blood (CB) plasma IL-2, IL-17A, IL-31, and soluble CD14 (sCD14) were positively associated with pertussis IgG levels at 12 months, while CB plasma concentrations of APRIL and IL-33 were negatively associated. In contrast, CB concentrations of sCD14 and APRIL were positively associated with sustained tetanus IgG levels. A separate cross-sectional analysis of 18 mother/newborn pairs indicated that CB biomarkers were not due to transplacental transfer, but rather due to immune activation at the fetal/maternal interface. Elevated percentages of cord blood switched memory B cells were positively associated with 12-month HiB IgG levels. BAFF concentrations at 6 and 12 months were positively associated with pertussis and HiB IgG levels respectively.

Discussion

Sustained B cell immunity is highly influenced by early life immune dynamics beginning prior to birth. The findings provide important insights into how germinal center development shapes vaccine responses in healthy infants and provide a foundation for studies of conditions that impair infant immune development.

Soluble CD40 Ligand Levels in Children with Newly Diagnosed Graves’ Disease

OBJECTIVE

Soluble CD40 ligand (sCD40L) is elevated in various autoimmune disorders, which may have diagnostic and therapeutic implications. The aims of the current study were to evaluate serum sCD40L concentrations in children with newly diagnosed Graves’ disease (GD) and to correlate its levels with patients’ clinical and laboratory parameters.

METHODS

This study included 48 children with newly diagnosed GD and 48 healthy children. Serum thyroid-stimulating hormone (TSH) (TSH, fT4 and fT3), TSH receptor antibodies (TRAbs), high sensitivity C-reactive protein (hsCRP) and sCD40L levels and thyroid volume were measured.

RESULTS

Compared to control subjects, children with GD had higher thyroid volume standard deviation scores (SDS) (p=0.001), and higher levels of hsCRP (p=0.001), TRAbs (p=0.001) and sCD40L (p=0.001). Significant correlations were found between sCD40L and age (p=0.01), thyroid volume SDS (p=0.001), hsCRP (p=0.01) and TRAbs (p=0.001). In multivariate analysis, sCD40L concentrations were correlated with TRAbs [odds ratio (OR)=3.1, 95% confidence intervals (CI): 2.2-2.7, p=0.001] and thyroid volume SDS (OR=2.1, 95% CI: 1.2-2.7, p=0.001).

CONCLUSION

This preliminary study has evidence of high concentrations of sCD40L in children with newly diagnosed GD and a correlation between sCD40L and both TRAbs and thyroid volume, which may indicate a biologically active role for sCD40L in the pathogenesis of GD.

Serum and cerebrospinal fluid immune mediators in children with autistic disorder: a longitudinal study

BACKGROUND

The causes of autism likely involve genetic and environmental factors that influence neurobiological changes and the neurological and behavioral features of the disorder. Immune factors and inflammation are hypothesized pathogenic influences, but have not been examined longitudinally.

METHODS

In a cohort of 104 participants with autism, we performed an assessment of immune mediators such as cytokines, chemokines, or growth factors in serum and cerebrospinal fluid (n = 67) to determine potential influences of such mediators in autism.

RESULTS

As compared with 54 typically developing controls, we found no evidence of differences in the blood profile of immune mediators supportive of active systemic inflammation mechanisms in participants with autism. Some modulators of immune function (e.g., EGF and soluble CD40 ligand) were increased in the autism group; however, no evidence of group differences in traditional markers of active inflammation (e.g., IL-6, TNFα, IL-1β) were observed in the serum. Further, within-subject stability (measured by estimated intraclass correlations) of most analytes was low, indicating that a single measurement is not a reliable prospective indicator of concentration for most analytes. Additionally, in participants with autism, there was little correspondence between the blood and CSF profiles of cytokines, chemokines, and growth factors, suggesting that peripheral markers may not optimally reflect the immune status of the central nervous system. Although the relatively high fraction of intrathecal production of selected chemokines involved in monocyte/microglia function may suggest a possible relationship with the homeostatic role of microglia, control data are needed for further interpretation of its relevance in autism.

CONCLUSIONS

These longitudinal observations fail to provide support for the hypothesized role of disturbances in the expression of circulating cytokines and chemokines as an indicator of systemic inflammation in autism. ClinicalTrials.gov, NCT00298246.

Plasma-mediated immune suppression: a neonatal perspective

Plasma is a rich mixture of immune regulatory factors that shape immune cell function. This immunomodulatory role of plasma is especially important in neonates. To maintain in utero feto-maternal tolerance and to allow for microbial colonization after birth, the neonatal immune system is biased against pro-inflammatory responses while favoring immune suppression. Therefore, the neonatal period provides a unique opportunity to study the physiologic mechanisms regulating the immune system. Several recent studies in neonates have identified plasma factors that play a key role in immune regulation. Insight into immune regulation by neonatal and adult plasma may have clinical implications, because plasma is easily accessible, affordable, and widely available. Herein, we review plasma-mediated immune regulation, with specific focus on neonatal plasma. We discuss how immune suppression is a key function of plasma and provide a systematic overview of the published literature regarding plasma-derived immune suppressive proteins, lipids, purines, and sugars. Finally, we outline how immune regulation by these factors, which are particularly abundant in neonatal plasma, may eventually be used to treat immune-mediated diseases, such as autoimmune, allergic, and inflammatory diseases.

The PPAR-Platelet Connection: Modulators of Inflammation and Potential Cardiovascular Effects

Historically, platelets were viewed as simple anucleate cells responsible for initiating thrombosis and maintaining hemostasis, but clearly they are also key mediators of inflammation and immune cell activation. An emerging body of evidence links platelet function and thrombosis to vascular inflammation. peroxisome proliferator-activated receptors (PPARs) play a major role in modulating inflammation and, interestingly, PPARs (PPARβ/δ and PPARγ) were recently identified in platelets. Additionally, PPAR agonists attenuate platelet activation; an important discovery for two reasons. First, activated platelets are formidable antagonists that initiate and prolong a cascade of events that contribute to cardiovascular disease (CVD) progression. Dampening platelet release of proinflammatory mediators, including CD40 ligand (CD40L, CD154), is essential to hinder this cascade. Second, understanding the biologic importance of platelet PPARs and the mechanism(s) by which PPARs regulate platelet activation will be imperative in designing therapeutic strategies lacking the deleterious or unwanted side effects of current treatment options.

Aspirin resistance following pediatric cardiac surgery

INTRODUCTION

Aspirin is often used to prevent thrombosis in pediatric cardiac surgery. The primary study aim was to assess aspirin resistance in this context. Secondary aims were to evaluate (1) the relationship between elevated inflammatory markers and thrombosis and (2) aspirin's effect on these levels.

MATERIALS AND METHODS

This was a prospective observational study of children undergoing cardiac surgery managed with and without aspirin. Aspirin response was assessed using the VerifyNow system and urinary 11-dehydrothromboxane B2 (uTxB2) measurements. Laboratory studies of inflammation were also obtained.

RESULTS

101 subjects were studied; 50 received aspirin. Six subjects (5.9%), 5 aspirin-treated, experienced symptomatic thrombosis. When measured by VerifyNow resistance was 43% after aspirin suppositories and 14% after additional days of oral aspirin. There was no correlation with thrombosis. Upper quartile post-operative day (POD) #5 uTxB2 was correlated with thrombosis in aspirin treated subjects (p<0.01). High risk aspirin-treated subjects who experienced thrombosis had higher POD#5 uTxB2. This finding did not reach statistical significance (p=0.07). Elevated pre-operative C-reactive protein (CRP) was independently associated with thrombosis (p<0.02) in all subjects and in high risk subjects (p=0.01). Inflammatory markers were not affected by aspirin.

CONCLUSIONS

Aspirin inhibited ex-vivo platelet function with a low incidence of resistance. Elevated POD#5 uTxB2 and pre-operative CRP were correlated with thrombosis in aspirin treated subjects. Further studies are needed to determine whether children with high levels of uTxB2 despite aspirin therapy and/or those with elevated preoperative CRP are at increased risk for thrombosis.