Akkermansia muciniphila phospholipid induces homeostatic immune responses.

Multiple studies have established associations between human gut bacteria and host physiology, but determining the molecular mechanisms underlying these associations has been challenging1-3. Akkermansia muciniphila has been robustly associated with positive systemic effects on host metabolism, favourable outcomes to checkpoint blockade in cancer immunotherapy and homeostatic immunity4-7. Here we report the identification of a lipid from A. muciniphila's cell membrane that recapitulates the immunomodulatory activity of A. muciniphila in cell-based assays8. The isolated immunogen, a diacyl phosphatidylethanolamine with two branched chains (a15:0-i15:0 PE), was characterized through both spectroscopic analysis and chemical synthesis. The immunogenic activity of a15:0-i15:0 PE has a highly restricted structure-activity relationship, and its immune signalling requires an unexpected toll-like receptor TLR2-TLR1 heterodimer9,10. Certain features of the phospholipid's activity are worth noting: it is significantly less potent than known natural and synthetic TLR2 agonists; it preferentially induces some inflammatory cytokines but not others; and, at low doses (1% of EC50) it resets activation thresholds and responses for immune signalling. Identifying both the molecule and an equipotent synthetic analogue, its non-canonical TLR2-TLR1 signalling pathway, its immunomodulatory selectivity and its low-dose immunoregulatory effects provide a molecular mechanism for a model of A. muciniphila's ability to set immunological tone and its varied roles in health and disease.

PEBP1 acts as a rheostat between prosurvival autophagy and ferroptotic death in asthmatic epithelial cells.

Temporally harmonized elimination of damaged or unnecessary organelles and cells is a prerequisite of health. Under Type 2 inflammatory conditions, human airway epithelial cells (HAECs) generate proferroptotic hydroperoxy-arachidonoyl-phosphatidylethanolamines (HpETE-PEs) as proximate death signals. Production of 15-HpETE-PE depends on activation of 15-lipoxygenase-1 (15LO1) in complex with PE-binding protein-1 (PEBP1). We hypothesized that cellular membrane damage induced by these proferroptotic phospholipids triggers compensatory prosurvival pathways, and in particular autophagic pathways, to prevent cell elimination through programmed death. We discovered that PEBP1 is pivotal to driving dynamic interactions with both proferroptotic 15LO1 and the autophagic protein microtubule-associated light chain-3 (LC3). Further, the 15LO1-PEBP1-generated ferroptotic phospholipid, 15-HpETE-PE, promoted LC3-I lipidation to stimulate autophagy. This concurrent activation of autophagy protects cells from ferroptotic death and release of mitochondrial DNA. Similar findings are observed in Type 2 Hi asthma, where high levels of both 15LO1-PEBP1 and LC3-II are seen in HAECs, in association with low bronchoalveolar lavage fluid mitochondrial DNA and more severe disease. The concomitant activation of ferroptosis and autophagy by 15LO1-PEBP1 complexes and their hydroperoxy-phospholipids reveals a pathobiologic pathway relevant to asthma and amenable to therapeutic targeting.

Significance of Anti-Phosphatidylethanolamine Antibodies in the Pathogenesis of Recurrent Pregnancy Loss.

Anti-phosphatidylethanolamine antibody (aPE), an anti-phospholipid autoantibody (aPL), has been proposed as a factor in recurrent pregnancy loss (RPL). However, conflicting views exist on the pathogenicity of RPL, and aPE has not yet been included in the classification criteria for antiphospholipid syndrome (APS). Here, we aimed to determine the clinical importance of examining aPE. aPE (IgG, IgM) was measured in 1705 patients with a history of RPL and re-examined after a 12-week interval in patients who tested positive. Persistent positive patients were administered low-dose aspirin during the subsequent pregnancy and clinical outcomes depending on the presence, type, and persistence of aPE were evaluated. Among the patients positive for aPE IgG and aPE IgM in the first examination (n = 117; 6.87%, and n = 235; 13.6%, respectively), 31.5% and 37.6% were negative upon re-examination, respectively. Moreover, among the cases with known pregnancy outcome, the miscarriage rate in the cumulative positive aPE group was 32.6% (29/89), which did not differ significantly from that of the aPE negative group (27.7%; 80/209; P = 0.178). Alternatively, the miscarriage rate in the persistently positive group was 40.7% (22/54), which was significantly higher than that in the transient positive group, 20.0% (7/35) (P = 0.041). Particularly, this difference become more significant when focusing on aPE IgM, 46.9% (15/32) in the persistent, compared with 16.7% (4/24) in the transient positive group (P = 0.024). aPE IgM is suggested to serve as a pathogenic aPL together with anti-cardiolipin antibodies and lupus anticoagulants, particularly if these factors persist over an extended period of time.

[Which place of antiphosphatidylethanolamine antibodies research in seronegative antiphospholipid syndrome suspicion?] / Quelle place pour la recherche des anticorps antiphosphatidyléthanolamine dans la suspicion du syndrome des antiphospholipides séronégatif ?

PURPOSE: Antiphospholipid syndrome (APS) is a clinico-biological syndrome, which associates vascular injury and persisting antiphospholipid antibodies (aPL). Patients with clinical symptoms of APS but without aPL are defined as "seronegative APS" (SNAPS). The aim of this study was to evaluate antiphosphatidylethanolamine antibody (aPE) investigation in patients with SNAPS suspicion. METHODS: This retrospective study was conducted in patients with SNAPS suspicion. A homemade enzyme-linked immunosorbent assay (ELISA) was used to search for aPE. The results of this homemade method were compared with those from a global screening ELISA. RESULTS: Two hundred twenty-eight patients with SNAPS suspicion were included. Among them, 58.3% had a thrombotic event. The homemade ELISA found positive persisting aPE in 23 patients (10%): 15 with a thrombotic event, 6 with obstetrical morbidity and 2 with a combined event. The global screening ELISA was positive in only 11 of these 23 patients (47.8%). CONCLUSION: These results suggest the implication of aPE in SNAPS.

Early endosome as a pathogenic target for antiphosphatidylethanolamine antibodies.

Phosphatidylethanolamine (PE) is a major phospholipid species with important roles in membrane trafficking and reorganization. Accumulating clinical data indicate that the presence of circulating antibodies against PE is positively correlated with the symptoms of antiphospholipid syndromes (APS), including thrombosis and repeated pregnancy loss. However, PE is generally sequestered inside a normal resting cell, and the mechanism by which circulating anti-PE antibodies access cellular PE remains unknown. The studies presented here were conducted with synthetic PE-binding agents, plasma samples from patients with anti-PE autoimmunity, and purified anti-PE antibodies. The results suggest that the cellular vulnerability to anti-PE antibodies may be mediated by the binding of PE molecules in the membrane of the early endosome. Endosomal PE binding led to functional changes in endothelial cells, including declines in proliferation and increases in the production of reactive oxygen species, as well as the expression of inflammatory molecules. Collectively, our findings provide insight into the etiology of anti-PE autoimmunity and, because endosomes are of central importance in almost all types of cells, could have important implications for a wide range of biological processes.

A molecular basis of human T cell receptor autoreactivity toward self-phospholipids.

Human T cell autoreactivity toward lipid antigens presented by CD1 proteins can manifest in numerous diseases, including psoriasis, contact hypersensitivities, and allergies. However, the molecular mechanisms for regulating T cell autoreactivity toward lipid antigens remain unclear. We determined the basis for T cell receptor (TCR) autoreactivity toward CD1b bound to self-phospholipids. The spectrum of self-antigens captured by CD1b skews toward abundant membrane phospholipids such as phosphatidylcholine and phosphatidylethanolamine. However, TCRs can specifically recognize rare phospholipids, including phosphatidylglycerol (PG). The structure of an autoreactive TCR bound to CD1b-PG shows that discrimination occurs through a marked induced fit movement of PG so that its polar head group fits snugly into the cationic cup of the TCR. Conversely, TCR binding toward ubiquitous self-phospholipids was sterically or electrostatically repelled. Accordingly, we describe a mechanism of TCR autoreactivity toward rare phospholipids and avoidance of autoreactivity to the most abundant self-phospholipids.

Increased levels of anti-phosphatidylcholine and anti-phosphatidylethanolamine antibodies in pediatric patients with cerebral infarction.

Cerebral infarction in children is rare and often occurs secondary to moyamoya disease, hereditary coagulopathies, vasculitis, antiphospholipid antibody syndrome, heart disease, mitochondrial disease. However, in some cases, the causes of cerebral infarction is unknown. In this study, we detected increased levels of serum anti-phosphatidylcholine and anti-phosphatidylethanolamine IgG antibodies in three pediatric patients with cerebral infarction whose primary disorders are unknown by routine examination. For the five disease control patients of cerebral infarction due to other primary disorders, there was no such increase in these antibodies levels. Phosphatidylcholine and phosphatidylethanolamine are major components of the phospholipids of vascular endothelial cells, while cardiolipin is a minor component. Anti-phosphatidylcholine and anti-phosphatidylethanolamine antibodies, as well as anti-cardiolipin antibody, might also be risk factors with cerebral infarction.

The outcome of ELISA for antiphosphatidylethanolamine antibodies is dependent on the composition of phosphatidylethanolamine.

OBJECTIVE: The presence of circulating autoantibodies against phosphatidylethanolamine (PE) has been shown to be positively associated with symptoms of antiphospholipid syndromes (APS). However, the current ELISA-based tests for antiphosphatidylethanolamine (aPE) antibodies remain inconsistent and controversial. The term PE refers to a collection of phospholipids that have phosphorylethanolamine head group as a common structural feature, but can vary in fatty acids with diverse physicochemical properties. The present study was to investigate, using synthetic positionally symmetrical PE species as a model system, the impact of PE structural variations on aPE ELISA. METHODS: Single and combinations of synthetic PE species, including 16:0 (fatty acid length:degree of unsaturation), 18:0, 18:1, 20:4 and 22:6, were screened with ELISA using serum samples from aPE patients and compared with chicken egg PE. There were a total of 37 aPE patient serum samples, including 11 cofactor-independent IgM, 14 ABP-independent IgG and 12 ABP-dependent aPE serum samples (3 IgM, 8 IgG and 1 IgA). The ELISA conditions were investigated for different isotypes and cofactor dependence. Based on the initial screening, adjustments in phospholipid compositions were made for achieving optimal OD readings. Finally, we isolated total IgG from aPE sera to validate different antigenic preferences. RESULTS: The antigenic preference was different among immunoglobulin isotypes and between cofactor-dependent versus cofactor-independent aPE antibodies. More specifically, 18:1 PE was a preferred antigen for cofactor-dependent aPE, whereas 20:4 PE was the preferred antigen for cofactor-independent IgG aPE. In contrast, cofactor-independent IgM aPE appeared to have a general preference for a more complex PE combination with longer fatty acids and a higher degree of unsaturation. CONCLUSION: The present data indicated that the outcome of aPE ELISA was dependent on the composition and physicochemical properties of PE antigens. The discovery that aPE antibodies may have different antigenic preferences could shed light on the nature of their binding interactions.

[Association between the presence of antiphospholipid antibodies and the occurrence of autism spectrum disorder in childhood]. / Lien entre trouble du spectre autistique de l'enfant et anticorps antiphospholipides : une étude cas-témoin.

OBJECTIVES: To evaluate the association between the presence of antiphospholipid (APL) antibodies and the occurrence of autism spectrum disorder (ASD) in childhood. METHODS: A prospective, monocentric case-control study from February 2012 to August 2014 comparing the APL antibodies of children with ASD (group 1) and children without ASD (group 2). RESULTS: Group 1 consisted of 44 children with ASD defined by clinical, genetic, metabolic, and morphological criteria. Group 2 consisted of 26 control children without ASD. One of children with ASD (2.3 %) had persistent anticardiolipin (ACL) antibodies, five of them (11.4 %) had persistent APL antibodies, one of them (2.3 %) had antiannexin V (AAV) antibodies, and two of them (4.5 %) had antiphosphatidylethanolamine (APE) antibodies. Two of the control children (7.7 %) had persistent APL antibodies. None of them had persistent ACL, AAV, or APE antibodies. Comparing group 1 and 2 children, no significant difference was found between the presence and the titers of conventional and non conventional antibodies (P<0.05). Furthermore, one mother of an autistic child (3 %) had persistent APL antibodies. CONCLUSION: ASD had no significant relation with the presence of APL antibodies.

Association of anti phosphatidyl ethanolamine antibodies and low complement levels in systemic sclerosis patients--results of a cross-sectional study.

Some systemic sclerosis (Ssc) patients express antiphospholipid antibodies and their percentage varies within studies in the literature. The particular role of these antibodies in clinical manifestations of Ssc is still unknown. The aim of the study was to examine an extended panel of antiphospholipid antibodies in Ssc patients who did not have any clinical features of antiphospholipid antibody syndrome. A cross-sectional study was designed and 36 consecutive patients with Ssc were recruited. A relatively high proportion of patients (14 patients - 38.9%) had antiphospholipid antibody presence. Most Ssc patients (11 patients - 30.6%) had IgM anti phosphatidyl ethanolamine antibodies. Serum IgM anti phosphatidyl ethanolamine antibodies, IgM anti prothrombin and IgG anti ß2 glycoprotein 1 antibodies were associated with low complement levels in Ssc patients. In multivariate analysis, only serum IgM anti phosphatidyl ethanolamine antibodies concentration and serum IgG anti ß2 glycoprotein 1 antibodies concentration were independently associated with hypocomplementemia after adjusting for age and gender. No other correlations with Ssc clinical characteristics were found. In conclusion, antiphospholipid antibodies are present in a large proportion of Ssc patients who do not have clinical features or a history of antiphospholipid antibodies. IgM anti phosphatidyl ethanolamine antibodies seem to be more frequent and the dominant antiphospholipid antibody type in the group recruited from the Romanian Ssc population.

Seronegative Antiphospholipid Syndrome with Anti-phosphatidylethanolamine Antibody in a Boy.

Antiphospholipid syndrome (APS) is an autoimmune disease caused by antiphospholipid antibodies. At our institution, APS is diagnosed on the basis of the Sapporo criteria, which consist of thrombosis and recurrent pregnancy-related complications and the following laboratory findings: the presence of lupus anticoagulant, anticardiolipin antibody, or anti-ß2 glycoprotein 1 antibody. However, we sometimes treat patients we strongly suspect of having APS but who do not satisfy the laboratory criteria. To accommodate such suspected cases, a subtype of APS termed seronegative APS has been proposed. Here, we report on a man with chronic thromobocytopenic purpura since the age of 3 years and multiple cerebral infarctions since the age of 14 years who finally received a diagnosis of seronegative APS with positive antiphosphatidylethanolamine antibodies.

Autoantibodies to Factor XII and Kininogen-Dependent Antiphosphatidylethanolamine Antibodies in Patients with Recurrent Pregnancy Loss Augment Platelet Aggregation.

PROBLEM: Numerous studies have suggested that factor XII (FXII) deficiency, autoantibodies to FXII (anti-FXII), and antiphosphatidylethanolamine antibodies (aPE) are associated with recurrent pregnancy loss (RPL). aPE in RPL patients recognize the LDC27 peptide of kininogen domain 3. Anti-FXII in RPL patients recognizes the heavy chain of FXII, especially the amino-terminal sequences IPP30 peptide. Previous studies suggested that LDC27 and IPP30 are the responsible sites competing for the same binding site on platelets and inhibiting augmentation of thrombin-induced platelet aggregation. Our aim was to study the influence of antibodies to LDC27 and IPP30 on platelet aggregation. METHODS OF STUDY: In fifteen healthy volunteers, platelet aggregation induced by γ-thrombin in the presence or absence of antibodies to LDC27 and IPP30 was measured. Sixteen RPL patients who were positive for anti-FXII were measured for spontaneous small platelet aggregate (SSPA) formation. RESULTS AND CONCLUSIONS: Antibodies to LDC27 and IPP30 markedly increased aggregation of normal platelets stimulated by γ-thrombin. Augmentation of SSPA formation was more frequent in the patients with RPL who were positive for anti-FXII than in the control group (P = 0.003). This study strongly supports the hypothesis that aPE and anti-FXII may cause RPL due to disruption of the normal antithrombotic effects of kininogens and FXII.

Chicken CD300a homolog is found on B lymphocytes, various leukocytes populations and binds to phospholipids.

The chicken CD300 cluster contains three genes that encode inhibitory, activating and soluble forms. In the present study, we have generated a monoclonal antibody against the inhibitory CD300L-B1 molecule. The mab 1D4 was specific for the CD300L-B1 form and showed no crossreactivity with the related CD300L-X1. Virtually all bursal cells expressed CD300L-B1, whereas only a small positive subset was found in thymus that was identified as thymic B cell subpopulation. In peripheral tissues, CD300L-B1 was found to be expressed on lymphocyte subpopulations in blood and spleen. Double immunofluorescence analysis with B- and T-cell specific markers identified these subsets as B lymphocytes. In addition, analysis of PBMC revealed that CD300L-B1 was also present on monocytes, heterophils, blood NK cells and in vitro differentiated macrophages. We utilized a reporter cell line in order to identify potential ligands of CD300L-B1. When several phospholipids were tested, only phosphatidylserine and phosphatidylethanolamine were found to trigger strong reaction of the reporter cells. The two phospholipids elicited a response only in CD300L-B1 reporter cells, but not in CD300L-X1 reporter cells. Moreover the interaction could be blocked with the specific mab. In conclusion, we provide evidence for the expression of chicken CD300L-B1 on immature and mature B cells, monocytes, heterophils, macrophages and NK cells and identify phosphatidylserine and phosphatidylethanolamine as CD300L-B1 ligands.

[Antiphosphatidylethanolamine antibody as a marker of antiphospholipid syndrome?]. / Anticorps antiphosphatidyléthanolamine, un marqueur du syndrome des antiphospholipides ?

Antibody to phosphatidylethanolamine (aPE) are observed in thrombotic or obstetric manifestations suggestive of antiphospholipid syndrome (APS). aPE seem to be markers of thrombotic risk independent of conventional antiphospholipid antibodies (aPL). aPE assays are not standardized. There is no therapeutic recommendation for isolated aPE patients with thrombotic or obstetric events. Prospective studies have to be carried to better define the therapeutic management of these patients. Value of aPE in APS criteria is still not established.

Central retinal vein occlusion in a pediatric patient with SLE and antiphospholipid antibodies without anti-cardiolipin or anti-ß2 glycoprotein I antibodies.

BACKGROUND: Antiphospholipid antibody syndrome is characterized by venous and/or arterial thrombosis, and is found in patients with systemic lupus erythematosus. Its diagnosis requires the presence of both clinical and laboratory findings, such as positive anti-cardiolipin and anti-ß2 glycoprotein I antibodies and lupus anticoagulant. However, cardiolipin is a minor component of the vascular endothelial cells in human, and phosphatidylcholine and phosphatidylethanolamine are major components. CASE PRESENTATION: A 15-year-old female suddenly developed massive left intraretinal hemorrhaging due to central retinal vein occlusion. She also had a butterfly rash, and her laboratory findings revealed positive serum anti-nuclear antibodies and decreased serum complement. During this episode, she was diagnosed with systemic lupus erythematosus. Although she was negative for serum anti-cardiolipin IgG and anti-ß2 glycoprotein I antibodies as well as lupus anticoagulant, her serum anti-phosphatidylcholine, anti-phosphatidylethanolamine, anti-phosphatidylinositol and phosphatidylserine IgG antibodies levels were increased. CONCLUSION: Pediatric cases of central retinal vein occlusion are rare. Even in patients without anti-cardiolipin or anti-ß2 glycoprotein I antibodies and lupus anticoagulant, there is the potential for the development of antiphospholipid antibody-related thrombosis.

Use of thermodynamic coupling between antibody-antigen binding and phospholipid acyl chain phase transition energetics to predict immunoliposome targeting affinity.

Thermodynamic analysis of ligand-target binding has been a useful tool for dissecting the nature of the binding mechanism and, therefore, potentially can provide valuable information regarding the utility of targeted formulations. Based on a consistent coupling of antibody-antigen binding and gel-liquid crystal transition energetics observed for antibody-phosphatidylethanolamine (Ab-PE) conjugates, we hypothesized that the thermodynamic parameters and the affinity for antigen of the Ab-PE conjugates could be effectively predicted once the corresponding information for the unconjugated antibody is determined. This hypothesis has now been tested in nine different antibody-targeted echogenic liposome (ELIP) preparations, where antibody is conjugated to dipalmitoylphosphatidylethanolamine (DPPE) head groups through a thioether linkage. Predictions were satisfactory (affinity not significantly different from the population of values found) in five cases (55.6%), but the affinity of the unconjugated antibody was not significantly different from the population of values found in six cases (66.7%), indicating that the affinities of the conjugated antibody tended not to deviate appreciably from those of the free antibody. While knowledge of the affinities of free antibodies may be sufficient to judge their suitability as targeting agents, thermodynamic analysis may still provide valuable information regarding their usefulness for specific applications.

Modified phosphatidylethanolamines induce different levels of cytokine expression in monocytes and dendritic cells.

Glycation of phosphatidylethanolamine (PE) is a reaction that is known to occur under the chronic hyperglycemic conditions found in diabetes. Glycated phosphatidylethanolamines were found in plasma and atherosclerotic plaques of diabetic patients, and its presence was correlated with increased oxidative stress. Moreover, upregulation of cytokines and other inflammatory mediators can be observed not only in diabetes, but also under oxidized phosphatidylcholine stimulation. In this study, we evaluate the effect of dipalmitoyl-phosphatidylethanolamine (DPPE) and linoleoyl-palmitoyl-phosphatidylethanolamine (PLPE) structural oxidation, glycation and glycoxidation, on monocyte and myeloid dendritic cell stimulation. Expression of cytokines, IL-1ß, IL-6, IL-8, MIP-1ß and TNF-α, were determined using flow cytometry after cell stimulations with native PEs, oxidized, glycated and glycoxidized PEs. Native PE, PLPE and DPPE, and all modified PEs were able to increase the stimulation levels of monocytes and mDCs. Generally, in monocytes and mDCs stimulation, GluOxPLPE and GluDPPE were the PLPE/DPPE modifications that induced the most pronounced rise in cytokine production. However, GluOxDPPE was the DPPE modification that produced the lowest stimulation levels of mDCs and monocytes. Our results indicate that glycated PE and glycoxidized PE may have an important contribution to the low-grade systemic inflammation associated with diabetes and to the development of diabetic complications.

Lymphoid tissue phospholipase A2 group IID resolves contact hypersensitivity by driving antiinflammatory lipid mediators.

Resolution of inflammation is an active process that is mediated in part by antiinflammatory lipid mediators. Although phospholipase A2 (PLA2) enzymes have been implicated in the promotion of inflammation through mobilizing lipid mediators, the molecular entity of PLA2 subtypes acting upstream of antiinflammatory lipid mediators remains unknown. Herein, we show that secreted PLA2 group IID (PLA2G2D) is preferentially expressed in CD11c(+) dendritic cells (DCs) and macrophages and displays a pro-resolving function. In hapten-induced contact dermatitis, resolution, not propagation, of inflammation was compromised in skin and LNs of PLA2G2D-deficient mice (Pla2g2d(-/-)), in which the immune balance was shifted toward a proinflammatory state over an antiinflammatory state. Bone marrow-derived DCs from Pla2g2d(-/-) mice were hyperactivated and elicited skin inflammation after intravenous transfer into mice. Lipidomics analysis revealed that PLA2G2D in the LNs contributed to mobilization of a pool of polyunsaturated fatty acids that could serve as precursors for antiinflammatory/pro-resolving lipid mediators such as resolvin D1 and 15-deoxy-Δ(12,14)-prostaglandin J2, which reduced Th1 cytokine production and surface MHC class II expression in LN cells or DCs. Altogether, our results highlight PLA2G2D as a "resolving sPLA2" that ameliorates inflammation through mobilizing pro-resolving lipid mediators and points to a potential use of this enzyme for treatment of inflammatory disorders.

Vaxfectin adjuvant improves antibody responses of juvenile rhesus macaques to a DNA vaccine encoding the measles virus hemagglutinin and fusion proteins.

DNA vaccines formulated with the cationic lipid-based adjuvant Vaxfectin induce protective immunity in macaques after intradermal (i.d.) or intramuscular (i.m.) delivery of 0.5 to 1 mg of codon-optimized DNA encoding the hemagglutinin (H) and fusion (F) proteins of measles virus (MeV). To characterize the effect of Vaxfectin at lower doses of H+F DNA, rhesus macaques were vaccinated twice with 20 µg of DNA plus Vaxfectin i.d., 100 µg of DNA plus Vaxfectin i.d., 100 µg of DNA plus Vaxfectin i.m. or 100 µg of DNA plus phosphate-buffered saline (PBS) i.m. using a needleless Biojector device. The levels of neutralizing (P = 0.036) and binding (P = 0.0001) antibodies were higher after 20 or 100 µg of DNA plus Vaxfectin than after 100 µg of DNA plus PBS. Gamma interferon (IFN-γ)-producing T cells were induced more rapidly than antibody, but were not improved with Vaxfectin. At 18 months after vaccination, monkeys were challenged with wild-type MeV. None developed rash or viremia, but all showed evidence of infection. Antibody levels increased, and IFN-γ- and interleukin-17-producing T cells, including cells specific for the nucleoprotein absent from the vaccine, were induced. At 3 months after challenge, MeV RNA was detected in the leukocytes of two monkeys. The levels of antibody peaked 2 to 4 weeks after challenge and then declined in vaccinated animals reflecting low numbers of bone marrow-resident plasma cells. Therefore, Vaxfectin was dose sparing and substantially improved the antibody response to the H+F DNA vaccine. This immune response led to protection from disease (rash/viremia) but not from infection. Antibody responses after challenge were more transient in vaccinated animals than in an unvaccinated animal.

Seronegative antiphospholipid syndrome.

APS is an autoimmune disease that leads to arterial and/or venous thrombosis, recurrent pregnancy loss and persistently positive aPLs. Patients with clinical manifestations highly suggestive of APS but persistently negative conventional aPLs are classified as having seronegative APS. Ongoing research has revealed the existence of non-criteria antibodies proposed to be relevant to APS and that can be potentially included in the disease's classification criteria. We present a literature review on the most promising antibodies of this heterogeneous aPL family, which includes antibodies to a zwitterionic phospholipid, namely phosphatidylethanolamine, phospholipid-binding plasma proteins, phospholipid-protein complexes and anionic phospholipids other than cardiolipin. Although these molecules can increase the diagnostic yield of APS, their clinical relevance is still debatable and needs to be confirmed by interlaboratory efforts toward standardizing diagnostic tools, in addition to experimental data and larger longitudinal studies.