Hiding Lipid Presentation: Viral Interference with CD1d-Restricted Invariant Natural Killer T (iNKT) Cell Activation

The immune system plays a major role in protecting the host against viral infection. Rapid initial protection is conveyed by innate immune cells, while adaptive immunity (including T lymphocytes) requires several days to develop, yet provides high specificity and long-lasting memory. Invariant natural killer T (iNKT) cells are an unusual subset of T lymphocytes, expressing a semi-invariant T cell receptor together with markers of the innate NK cell lineage. Activated iNKT cells can exert direct cytolysis and can rapidly release a variety of immune-polarizing cytokines, thereby regulating the ensuing adaptive immune response. iNKT cells recognize lipids in the context of the antigen-presenting molecule CD1d. Intriguingly, CD1d-restricted iNKT cells appear to play a critical role in anti-viral defense: increased susceptibility to disseminated viral infections is observed both in patients with iNKT cell deficiency as well as in CD1d- and iNKT cell-deficient mice. Moreover, viruses have recently been found to use sophisticated strategies to withstand iNKT cell-mediated elimination. This review focuses on CD1d-restricted lipid presentation and the strategies viruses deploy to subvert this pathway.     

Selectivity in the potentiation of antibacterial activity of α-peptide/β-peptoid peptidomimetics and antimicrobial peptides by human blood plasma

Antimicrobial peptides (AMPs) are promising leads for novel antibiotics; however, their activity is often compromised under physiological conditions. The purpose of this study was to determine the activity of α-peptide/β-peptoid peptidomimetics and AMPs against Escherichia coli and Staphylococcus aureus in the presence of human blood-derived matrices and immune effectors. The minimum inhibitory concentration (MIC) of two peptidomimetics against E. coli decreased by up to one order of magnitude when determined in 50% blood plasma as compared to MHB media. The MIC of a membrane-active AMP, LL-I/3, also decreased, whereas two intracellularly acting AMPs were not potentiated by plasma. Blood serum had no effect on activity against E. coli and neither matrix had an effect on activity against S. aureus. Unexpectedly, physiological concentrations of human serum albumin did not influence activity. Plasma potentiation was not mediated by an LL-37 analogue, lysozyme or hydrogen peroxide; however, plasma potentiation of activity was abolished when the complement system was heat-inactivated. Time-course experiments indicated that potentiation was due to plasma-mediated effects on bacterial cells prior to activities of peptidomimetics. The unexpected enhancement of antibacterial activity of peptidomimetics and AMPs under physiological conditions significantly increases the therapeutic potential of these compounds.     

Repair of erosions in rheumatoid arthritis does occur. Results from 2 studies by the OMERACT Subcommittee on Healing of Erosions

The committee was charged with determining whether healing of erosions in rheumatoid arthritis (RA) occurs. Two exercises were performed: The first asked the committee members, as a panel of experts, to express agreement or disagreement with the presence of improvement and features of bone reaction to injury in images submitted by members as examples of healing. The second presented panel members with 28 pairs of serial images, 14 chosen to illustrate progression and 14 chosen to illustrate repair. Agreement was tested on 8 items: global judgment on which image in the pair was better, relative size of the erosion in the 2 images, judgment on which image was first, presence and extent of sclerosis, cortication, filling-in, remodeling, and reconstituting normal structure. Our results showed good agreement, among the 15 respondents, on global assessment of which image was better and which image showed the smaller erosion. Correct assignment of sequence was only slightly better than expected by chance (in 65% of the cases). Agreement was poor regarding the presence of morphologic features of bone repair. A majority of a panel of experts agreed on which 2nd images in a set of paired, serial images represented improvement and which showed progression based on global assessment of which was better and on size of erosion. Features of bone repair were not distinctive and did not enable the panel to deduce the correct sequence of the serial images. This study provides evidence that repair of bone damage in RA does occur, resulting in some degree of improvement, which was recognized by a majority of a panel of experts.     

The Diagnoses and Outcomes of Emergency Patients With an Elevated D-Dimer Over the Next 90 Days

BackgroundIt is not known what diagnoses are associated with an elevated D-dimer in unselected patients attending emergency departments (ED), nor have their associated outcomes been determined.MethodsThis was a prospective observational study of 1612 unselected patients attending a Danish ED, with 100% follow-up for 90 days after presentation.ResultsThe 765 (47%) ED patients with an elevated D-dimer level (ie, ≥ 0.5 mg/L) were more likely to be admitted to hospital (P <.0001), re-present to health services (P = .02), and die within 90 days (8.1% of patients, P <.0001). Only 10 patients with a normal D-dimer level (1.2%) died within 90 days. Five had chronic obstructive pulmonary disease and infection, and 5 had cancer (4 of whom also had infection). Venous thromboembolism, infection, neoplasia, anemia, heart failure, and unspecified soft tissue disorders were significantly associated with an elevated D-dimer level. Of the 72 patients with venous thromboembolism, 20 also had infection, 8 had cancer, and 4 had anemia. None of the patients with heart failure, stroke, or acute myocardial infarction with a normal D-dimer level died within 90 days.ConclusionsIn this study, nearly half of all patients attending the ED had an elevated D-dimer level, and these patients were more likely to be admitted to hospital and to re-present to health services or die within 90 days. In this unselected ED patient population, elevated D-dimer levels were found to not only be significantly associated with venous thromboembolism, but to also be associated with infection, cancer, heart failure, and anemia.     

Long-term risk of adverse cardiovascular outcomes associated with cutaneous lupus erythematosus: a nationwide cohort study

Clinical Rheumatology - Autoimmune diseases, including systemic lupus erythematosus, have been associated with a substantial risk of cardiovascular morbidity and mortality. However, data on the...     

Which ultrasound lesions contribute to dactylitis in psoriatic arthritis and their reliability in a clinical setting

Clinical Rheumatology - To explore the frequency of ultrasound elementary lesions in dactylitis in psoriatic arthritis (PsA), and the reliability of scoring these lesions in a clinical setting. In...