Total Serum IgM Research Articles

First-in-human clinical trial to assess pharmacokinetics, pharmacodynamics, safety, and tolerability of iscalimab, an anti-CD40 monoclonal antibody.

Iscalimab is a fully human, CD40 pathway blocking, nondepleting monoclonal antibody being developed as an immunosuppressive agent. We describe a first-in-human, randomized, double-blind, placebo-controlled study investigating the safety, tolerability, pharmacokinetics, and pharmacodynamics of iscalimab in healthy subjects and rheumatoid arthritis patients. Healthy subjects (n=56) received single doses of intravenous iscalimab (0.03, 0.1, 0.3, 1, or 3mg/kg), or subcutaneous iscalimab (3mg/kg), or placebo. Rheumatoid arthritis patients (n=20) received single doses of intravenous iscalimab (10 or 30mg/kg) or placebo. Iscalimab exhibited target-mediated drug disposition resulting in dose-dependent and nonlinear pharmacokinetics. Complete (≥90%) CD40 receptor occupancy on whole blood B cells was observed at plasma concentrations >0.3-0.4µg/mL. In subjects receiving 3mg/kg iscalimab, antibody responses to keyhole limpet hemocyanin were transiently suppressed. CD40 occupancy by iscalimab prevented ex vivo human rCD154-induced expression of CD69 on B cells in whole blood. All doses were generally safe and well tolerated, with no clinically relevant changes in any safety parameters, including no evidence of thromboembolic events. Iscalimab appears to be a promising blocker of the CD40-CD154 costimulatory pathway with potential use in transplantation and other autoimmune diseases.

Rheumatoid arthritis patients display B-cell dysregulation already in the na\xefve repertoire consistent with defects in B-cell tolerance

B cells are postulated to be central in seropositive rheumatoid arthritis (RA). Here, we use exploratory mass cytometry (n = 23) and next-generation sequencing (n = 19) to study B-cell repertoire shifts in RA patients. Expression of several B-cell markers were significantly different in ACPA+ RA compared to healthy controls, including an increase in HLA-DR across subsets, CD22 in clusters of IgM+ B cells and CD11c in IgA+ memory. Moreover, both IgA+ and IgG+ double negative (IgD− CD27−) CD11c+ B cells were increased in ACPA+ RA, and there was a trend for elevation in a CXCR5/CCR6high transitional B-cell cluster. In the RA BCR repertoire, there were significant differences in subclass distribution and, notably, the frequency of VH with low somatic hypermutation (SHM) was strikingly higher, especially in IgG1 (p < 0.0001). Furthermore, both ACPA+ and ACPA− RA patients had significantly higher total serum IgA and IgM compared to controls, based on serology of larger cohorts (n = 3494 IgA; n = 397 IgM). The observed elevated Ig-levels, distortion in IgM+ B cells, increase in double negative B cells, change in B-cell markers, and elevation of unmutated IgG+ B cells suggests defects in B-cell tolerance in RA. This may represent an underlying cause of increased polyreactivity and autoimmunity in RA.

Green Coffee Extract Improves Cardiometabolic Parameters and Modulates Gut Microbiota in High-Fat-Diet-Fed ApoE-/- Mice.

Chlorogenic acids (CGA) are the most abundant phenolic compounds in green coffee beans and in the human diet and have been suggested to mitigate several cardiometabolic risk factors. Here, we aimed to evaluate the effect of a water-based standardized green coffee extract (GCE) on cardiometabolic parameters in ApoE-/- mice and to explore the potential underlying mechanisms. Mice were fed an atherogenic diet without (vehicle) or with GCE by gavage (equivalent to 220 mg/kg of CGA) for 14 weeks. We assessed several metabolic, pathological, and inflammatory parameters and inferred gut microbiota composition, diversity, and functional potential. Although GCE did not reduce atherosclerotic lesion progression or plasma lipid levels, it induced important favorable changes. Specifically, improved metabolic parameters, including fasting glucose, insulin resistance, serum leptin, urinary catecholamines, and liver triglycerides, were observed. These changes were accompanied by reduced weight gain, decreased adiposity, lower inflammatory infiltrate in adipose tissue, and protection against liver damage. Interestingly, GCE also modulated hepatic IL-6 and total serum IgM and induced shifts in gut microbiota. Altogether, our results reveal the cooccurrence of these beneficial cardiometabolic effects in response to GCE in the same experimental model and suggest potential mediators and pathways involved.

Modulation of digestive enzyme activity, blood health, oxidative responses and growth-related gene expression in GIFT by heat-killed Lactobacillus plantarum (L-137)

The current study was performed to investigate the effects of dietary heat-killed Lactobacillus plantarum (HK L-137) on growth, digestive enzyme activity, intestinal morphology and oxidative status in genetically improved farmed tilapia (GIFT). For 12 weeks, fish were fed a control diet (HKL0) or a diet supplemented with HK L-137 at a concentration of 50 (HKL50), 100 (HKL100) or 1000 (HKL1000) mg kg−1 feed. At the final sampling, the HKL100 group had significantly (P < 0.05) increased performance parameters (FBW, WG, SGR and FER) compared to the control group, while the HKL50 and HKL1000 groups showed weaker improvements. Mucosal thickness and villus length were significantly (P < 0.05) increased in the HKL50 and HKL100 groups in the anterior, middle and posterior intestine, but muscle thickness was significantly (P < 0.05) improved only in the anterior and middle intestine. Amylase, lipase and protease activity was significantly (P < 0.05) increased in fish fed 50 or 100 mg HK L-137 per kg diet compared to control fish. Significant modulation of blood haematocrit, haemoglobin levels, and RBC and WBC counts (P < 0.05) occurred in fish fed HK L-137, while total cholesterol and GPT were decreased by HK L-137. Furthermore, antioxidative enzyme (SOD and CAT) activity were significantly (P < 0.05) higher in the HKL100 group than in the control group, while MDA levels were lower. Furthermore, fish fed HK L-137 showed enhanced total serum protein and IgM levels. Interestingly, qRT-PCR revealed significant (P < 0.05) upregulation of the growth-related gene IGF-I and the glucose regulation gene G6PD but downregulation of the fatty acid synthase (FAS) gene in all HKL groups compared to the control group. Thus, we conclude that the use of HK L-137 is an efficient strategy to achieve economically feasible and sustainable tilapia production.

Abnormal T-cell phenotype in episodic angioedema with hypereosinophilia (Gleich syndrome): Frequency, clinical implication, and prognosis

Episodic angioedema with eosinophilia (EAE) (Gleich syndrome) is a raredisorder consisting of recurrentepisodes of angioedema, hypereosinophilia, and frequent elevated serum IgM level. We conducted a retrospective multicenter nationwide study regarding the clinical spectrum and therapeutic management of patients with EAE in France. A total of 30 patients with a median age at diagnosis of 41years (range, 5-84) were included. The median duration of each crisis was 5.5days (range, 1-90), with swelling affecting mainly the face and the upper limbs. Total serum IgM levels were increased in 20 patients (67%). Abnormal T-cell immunophenotypes were detected in 12 patients (40%), of whom 5 (17%) showed evidence of clonal T-cell receptor gamma locus gene (TRG) rearrangement. The median duration of follow-up was 53months (range, 31-99). The presence of an abnormal T-cell population was the sole factor associated with a shorter time to flare (hazard ratio, 4.15; 95% confidence interval, 1.18-14.66; P=.02). At last follow-up, 3 patients (10%) were able to have all treatments withdrawn and 11 (37%) were in clinical and biologic remission with less than 10mg of prednisone daily. EAE is a heterogeneous condition that encompasses several disease forms. Although patients usually respond well to glucocorticoids, those with evidence of abnormal T-cell phenotype have a shorter time to flare.

Current status of the acquired immune system of Iranian patients with long-term complications of sulfur mustard poisoning.

Sulfur mustard (SM) is a powerful blistering chemical warfare agent that has genotoxic effects. Cells with excessive proliferation such as lymphocytes may inherit this cellular toxicity which can lead to their malfunctions in the long-term. This study was designed to evaluate the status of acquired immunity among SM poisoned veterans around three decades after exposure. Thirty five male Iranian veterans having at least 25% disability due to SM poisoning with long-term complications in the respiratory system, skin or eyes were investigated. Non-functional/functional tests including hematological parameters, immunostaining analysis, lymphocyte proliferation assay, cytokine profile, and levels of total serum IgM, IgG and IgA were performed. The results showed that most of the parameters of adaptive immune system of the veterans were currently within the normal ranges. However, changes in the proliferation index (PI) of lymphocytes showed problems with the lymphocytes which cannot be proliferated appropriately. PI values for PBMCs (peripheral blood mononuclear cells) in presence of PHA (Phytohemagglutinin-A) and LPS (lipopolysaccharide) mitogens were 1.16 ± 0.14 and 1.13 ± 0.07, respectively which are less than expected. Based on the results gathered in this study, most of the parameters of acquired immunity were normal. However, the observed failure of lymphocyte functions may disrupt physiological activity of whole immune system leading to long-term complications; including recurrent respiratory tract infections. Indeed, further cellular and molecular studies with regard to lymphocytes function are required to better understand the status of adaptive immunity in these patients. Graphical abstract ᅟ.

Dietary propionic acid enhances antibacterial and immunomodulatory effects of oxytetracycline on Nile tilapia, Oreochromis niloticus.

This study was carried out to evaluate the potential antibacterial and immunomodulatory effects of the dietary acidifier propionic acid (PA) when given alone or in combination with oxytetracycline (OTC) on Nile tilapia (Oreochromis niloticus). Apparently healthy O. niloticus (n =240; 52 ± 3.75g) were randomly allocated into four equal groups (n =60/group): control group fed a basal diet alone and the other three groups fed basal diets supplemented with either PA (200mg /kg of diet, PA group) or OTC (500mg/kg of diet, OTC group) alone or in combination (PA + OTC group). Each group was subdivided into two subgroups (n =30/subgroup, each subgroup had triplicate of 10 fish); subgroup (A) was used to evaluate the antibacterial effects with the aforementioned 2weeks feeding regime, and subgroup (B) was used to evaluate the immunomodulatory effects against Aeromonas hydrophila infection with similar 2weeks feeding regime. Among the four groups, PA + OTC group showed the highest significant (p< 0.0001) antibacterial activity as indicated by widest inhibition zones against A. hydrophila and lowest total gastrointestinal bacterial counts. Additionally, this group had the best immunomodulatory effect as noticed by a significant (p< 0.05) increase in total serum protein, globulin, IgM, phagocytic activity and index, lysosome activity, and significant (p< 0.05) upregulation in the expression levels of immunity-related genes (MHC I, MHC IIA, MHC IIB, Tlr7, IgM heavy chain, TNFα, and IL1β) in head-kidney. Notably, the combined dietary PA and OTC improved the hematological parameters and reduced the oxidative damage of hepatopancreas and head-kidney induced by OTC. This data suggests dietary PA as potential adjuvant to OTC in O. niloticus diets to get maximal antibacterial and immunomodulatory effects.

Dietary vitamin D3 supplementation protects laying hens against lipopolysaccharide-induced immunological stress

BackgroundThe effects of vitamin D on the immune function of laying hens are not well understood. This study investigated the effects of vitamin D3 (VD3) on laying performance and immunological functions in laying hens under Escherichia coli lipopolysaccharide (LPS) challenge.MethodsIn experiment one, 360 Jinghong-1 strain layers (32 weeks) were randomly divided into four groups with six replicates per group and 15 hens per replicate. Hens were fed a basal diet supplemented with different levels of VD3 (0; 500; 1500; or 3000 IU VD3/kg of diet) for 10 weeks to determine laying performance, egg quality, and other parameters. In experiment two, 24 Jinghong laying hens (32 weeks) were fed basal diets with either 0 or 3000 IU VD3/kg of diet. After 10 weeks of feeding, six hens from each treatment were injected intravenously with 8 mg/kg of body weight of either LPS or saline. Blood and spleen samples were obtained for immune parameter analysis 4 h after injection.ResultsVD3 deficiency reduced egg production and egg quality; in addition, feed intake and feed-to-egg ratio increased. No significant differences were observed in these parameters except eggshell strength between dietary VD3 supplemental levels at 500; 1500; and 3000 IU VD3/kg of diet. VD3 deficiency increased serum hormone (calcitonin, parathyroid hormone, estradiol, and progesterone) and cytokine (IL-6, IL-10) levels, the ratio of IFN-γ to IL-4, myeloperoxidase activity and total IgG content in the serum, and upregulated the blood CD3+ T cell population. Splenic retinoid X receptor (RXR), nuclear factor-κB (NF-κB), inducible nitric oxide synthase (iNOS), and polymeric immunoglobulin receptor (pIgR) gene mRNA levels were upregulated in VD3-deficienct hens. VD3 deficiency significantly reduced serum Follicle stimulating hormone (FSH) and Luteinizing hormone (LH) concentrations and the number of CD4+CD25+ T cells in the blood. These changes were completely normalized by VD3 sufficiency. LPS reduced serum LH concentration, splenic lysozyme, and pIgR gene mRNA levels. LPS induced an increase in total serum IgM levels and the percentage of CD8+ T cells in the blood. The changes were completely reversed by VD3 addition.ConclusionVD3 supplementation could protect laying hens not only from VD3 deficiency but also from immunological stress.

Recombinant phosphoglucomutase and CAMP factor as potential subunit vaccine antigens induced high protection against Streptococcus iniae infection in flounder (Paralichthys olivaceus).

The aim of this study was to screen vaccine candidates from virulence factors of Streptococcus iniae in flounder model. The immunogenicity of recombinant phosphoglucomutase (rPGM) and rCAMP factor was confirmed by Western blot. The percentage of surface membrane immunoglobulin-positive (sIg+ ) lymphocytes in peripheral blood leucocytes, the specific and total serum IgM and the activity of acid phosphatase (ACP) and peroxidase (POD) in flounder were determined with flow cytometry, ELISA and commercial enzyme activity kits, respectively, after intraperitoneal immunization with rPGM and rCAMP factor. The results showed that rPGM and rCAMP factor could induce significant rise in sIg+ lymphocytes, specific serum IgM and activities of ACP and POD. Additionally, the relative percent survival rate of the vaccinated flounder was 64 and 54% in challenge experiment using S. iniae, respectively. These results indicated that rPGM and rCAMP factor could evoke humoural and innate immune response in flounder and provide high-efficiency immunoprotection against S. iniae infection. Phosphoglucomutase (PGM) and CAMP factor were promising vaccine candidates against S. iniae in flounder. Phosphoglucomutase and CAMP factor have the potential to be vaccine candidates, which provide important information for us to develop the effective subunit vaccines, especially the multivaccine, against S .iniae in aquaculture.

In vitro phagocytosis of opsonized latex beads by HD11 cells as a method to assess the general opsonization potential of chicken serum

ABSTRACTOpsonins, an important arm of the innate immune system, are various soluble proteins, which play a critical role in destruction of invading pathogens directly or via engulfment of pathogens through the intermediate of phagocytosis. The diversity of opsonin profiles is under genetic influence and may be associated with variation in disease resistance. The aim of this study was to set up an assay to determine serum opsonophagocytic potential (OPp) for chicken sera by flow cytometry and to evaluate the assay using samples from different chicken lines. Two chicken lines selected for high and low concentrations of mannose-binding lectin, a known opsonin, in serum were used to establish the method. Furthermore, the presumed “robust” Hellevad chickens and two other commercial chicken lines (Hisex and Bovans) were tested to evaluate OPp as a parameter reflecting general immune competence. The results showed that Hellevad and Bovans chickens had higher OPp than Hisex chickens. There were no correlations between concentrations of total IgY or mannose-binding lectin and OPp. However, a strong positive correlation was observed between vaccine-induced infectious bronchitis virus titres and OPp. Moreover, inverse relationships were observed between concentrations of total serum IgM as well as natural antibody levels, and OPp. In conclusion, in vitro opsonophagocytosis assessment and determination of OPp may be of relevance when addressing general innate immunocompetence.RESEARCH HIGHLIGHTSA flow cytometry method was developed to assess poultry serum opsonophagocytosis potential.This method is based on serum-opsonin-coated polystyrene beads and HD11 cell phagocytosis.Serum samples from different commercial chicken lines were compared.Opsonophagocytic potential may be included in assay panels for general immune competence of poultry.

Identification of immunogenic proteins and evaluation of recombinant PDHA1 and GAPDH as potential vaccine candidates against Streptococcus iniae infection in flounder (Paralichthys olivaceus).

Streptococcus iniae is a major Gram-positive pathogen that causes invasive disease in fish worldwide. In this study, in order to identify immunogenic proteins for developing highly effective vaccine against S. iniae, whole-cell lysate proteins of S. iniae were analyzed by western blotting using flounder anti-S. iniae antibodies, and two positive protein bands of molecular weight 37 kDa and 40 kDa were screened, which were identified as pyruvate dehydrogenase E1 subunit alpha (PDHA1), BMP family ABC transporter substrate-binding protein (BMP) and L-lactate dehydrogenase (LDH), as well as ornithine carbamoyltransferase (OCT), lactate oxidas (LOx) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by mass spectrometry. Subsequently, the six recombinant proteins were produced and used to immunize healthy flounder, and the relative percent survival (RPS) value was 72.73%, 27.27%, 36.36%, 9.09%, 36.36% and 63.64% respectively after intraperitoneal challenge with live S. iniae, revealing that rPDHA1 and rGAPDH produced higher relative percent survival than formalin-killed S. iniae (36.36%). To further investigate the protective efficacy of rPDHA1 and rGAPDH, the proliferation of surface membrane immunoglobulin-positive (sIg+) lymphocytes in peripheral blood leucocytes, the total serum IgM, specific IgM against S. iniae and RPS were detected. The results showed that rPDHA1, rGAPDH and formalin-killed S. iniae significantly induced the proliferation of sIg+ lymphocytes, the production of total serum IgM and specific IgM as compared with the control group, and rGAPDH and rPDHA1 provide higher RPS (62.5% and 75%, respectively) again. These results demonstrated that rPDHA1 and rGAPDH are promising vaccine candidates against S. iniae infection in flounder.

The skin immune response of rainbow trout, Oncorhynchus mykiss (Walbaum), associated with puffy skin disease (PSD)

Puffy skin disease (PSD) is an emerging skin condition which affects rainbow trout, Oncorhynchus mykiss (Walbaum). The transmission pattern of PSD suggests an infectious aetiology, however, the actual causative infectious agent(s) remain(s) unknown. In the present study, the rainbow trout epidermal immune response to PSD was characterised. Skin samples from infected fish were analysed and classified as mild, moderate or severe PSD by gross pathology and histological assessment. The level of expression of 26 immune-associated genes including cytokines, immunoglobulins and cell markers were examined by TaqMan qPCR assays. A significant up-regulation of the gene expression of C3, lysozyme, IL-1β and T-bet and down-regulation of TGFβ and TLR3 was observed in PSD fish compared to control fish. MHCI gene expression was up-regulated only in severe PSD lesions. Histological examinations of the epidermis showed a significant increase in the number of eosinophil cells and dendritic melanocytes in PSD fish. In severe lesions, mild diffuse lymphocyte infiltration was observed. IgT and CD8 positive cells were detected locally in the skin of PSD fish by in situ hybridisation (ISH), however, the gene expression of those genes was not different from control fish. Total IgM in serum of diseased animals was not different from control fish, measured by a sandwich ELISA, nor was significant up regulation of IgM gene expression in PSD lesions observed. Taken together, these results show activation of the complement pathway, up-regulation of a Th17 type response and eosinophilia during PSD. This is typical of a response to extracellular pathogens (i.e. bacteria and parasites) and allergens, commonly associated with acute dermatitis.

The effects of prolonged azathioprine administration on blood cells, lymphocytes and immunoglobulins of Iranian mixed-breed dogs

Background: Azathioprine is an immunosuppressive agent that is used in a variety of dermatologic, digestive and hematologic disorders in both humans and small animals. Aims: The effects of long term Azathioprine administration on complete blood count, rate of CD4+ and CD8+ lymphocytes, serum immunoglobulins and protein concentrations of mixed-breed dogs were evaluated in this study. Methods: 24 healthy mixed-breed dogs were divided randomly into two equal control and treatment groups. Dogs in the treatment group received the therapeutic dose of Azathioprine for four months, while the dogs in the control group didn't receive this drug. Peripheral blood samples were taken from both two groups before and after the trial to check CBC, CD4+ and CD8+ lymphocytes and the concentrations of total protein, albumin, serum IgM and IgG. Results: There was significant decrease in the levels of WBC, RBC, hematocrit and CD4 lymphocyte and double positive CD4/CD8 rates (all p values< 0.001), concentrations of total protein, albumin, serum IgG and IgM (P values: 0.014, 0.001, 0.007 and 0.041 respectively) in treatment group after the trial. Conclusions: Myelotoxicity induced by Azathioprine could be the probable cause of decrements in the rate of WBC and RBC. Decrease in the rate of dpCD4/CD8 might be due to decrement in dpCD4/CD8 progenitor cells and/or decrease in the activation rate of single positive T cells as the result of pharmacological effect of Azathioprine. Disrupted synthesis processes, from genes to proteins through Azathioprine might be the cause of decreases in the level of serum gamma globulins and protein.

Utility of routine urine CMV PCR and total serum IgM testing of small for gestational age infants: a single center review.

Due to the extremely low incidence of TORCH (toxoplasmosis, rubella, CMV, herpes simplex virus) infections, diagnostic testing of all small for gestational age (SGA) infants aimed at TORCH etiologies may incur unnecessary tests and cost. To determine the frequency of urine CMV PCR and total IgM testing among infants with birth weight <10% and the rate of test positivity. To evaluate the frequency of alternative etiologies of SGA in tested infants. Retrospective chart review of SGA infants admitted to the neonatal intensive care unit (NICU) at NYU Langone Medical Center between 2007 and 2012. Subjects were classified as being SGA with or without intrauterine growth restriction (IUGR). The IUGR subjects were then further categorized as having either symmetric or asymmetric IUGR utilizing the Fenton growth chart at birth. Initial testing for TORCH infections, which included serum total IgM, CMV PCR and head ultrasound, were reviewed and analyzed. Three hundred and eighty-six (13%) infants from a total of 2953 NICU admissions had a birth weight ≤10th percentile. Of these, 44% were IUGR; 34% being symmetric IUGR and 10% asymmetric. A total of 32% of SGA infants had urine CMV PCR and total IgM tested with no positive results. As expected, significantly higher percentage of symmetric IUGR infants were tested compared to asymmetric IUGR and non-IUGR SGA infants, (64% vs. 47% vs. 19%) P≤0.01. However, 63% of infants with a known cause for IUGR had same testing done aimed at TORCH infections. We calculated additional charges of $64,065 that were incurred by such testing. The majority of infants in our study who received testing for urine CMV PCR and total IgM aimed at TORCH infections had one or more other known non-infectious etiologies for IUGR. Because the overall yield of such testing is extremely low, we suggest tests for possible TORCH infections may be limited to symmetric IUGR infants without other known etiologies. Improved guidelines testing for TORCH infections can result in reducing hospital charges and unnecessary studies.

Antibodies to Cyclic Citrullinated Peptides in Patients With Juvenile Idiopathic Arthritis and Patients With Rheumatoid Arthritis: Shared Expression of the Inherently Autoreactive 9G4 Idiotype.

Antibodies to cyclic citrullinated peptides (anti-CCP) in rheumatoid arthritis (RA) can express the inherently autoreactive gene VH 4-34, detected using the rat monoclonal antibody 9G4. Patients with the polyarticular subtype of juvenile idiopathic arthritis (JIA) share some but not all of the features of adult patients with RA. This study was undertaken to compare serologic findings for rheumatoid factor (RF), anti-CCP, and 9G4-expressing anti-CCP in a large JIA cohort with a cohort of adult RA patients. Serum from 88 patients with polyarticular JIA, 29 patients with enthesitis-related arthritis, 38 patients with extended oligoarthritis, 31 adolescent controls, 35 patients with RA, and 30 adult controls were tested for RF, for IgG, IgA, and IgM anti-CCP, and for 9G4-expressing anti-CCP by enzyme-linked immunosorbent assay. Total serum 9G4-positive IgM was also measured. Of 65 patients with RF-negative polyarticular JIA, 4 (6.2%) were IgG anti-CCP positive. Sera from 20 of 23 patients with RF-positive polyarticular JIA (87.0%), 24 of 35 patients with RA (68.6%), and 1 patient with extended oligoarthritis contained IgG anti-CCP. IgA and IgM anti-CCP levels were lower in the adolescent group (P < 0.01). Levels of 9G4-expressing anti-CCP were higher in patients with RF-positive polyarticular JIA than in those with RF-negative polyarticular JIA (P < 0.0001). Median levels of 9G4-expressing anti-CCP in patients with RF-positive polyarticular JIA and those with RA did not differ. Expression of 9G4 on serum total IgM was greater in patients with RF-positive polyarticular JIA than other adolescent groups (P < 0.01), but similar to adult RF-positive RA. In healthy individuals, 9G4-positive B cells comprise 5-10% of the peripheral blood pool but serum immunoglobulins utilizing VH 4-34 are disproportionately low. The idiotope recognized by 9G4 was detected on anti-CCP antibodies in >80% of patients with RF-positive polyarticular JIA. VH 4-34 usage by anti-CCP in both JIA and RA patients suggest elicitation of these autoantibodies through shared pathogenic B cell selection processes.

155 Higher igm anti oxidised ldl antibodies point to favourable plaque characteristics as determined by radio frequency intravascular ultrasound (rf-ivus) and near infrared spectroscopy (nirs) in the integrated imaging and biomarker study 3 (ibis-3)

BackgroundMalondialdehyde (MDA)-LDL is one of the main oxidation products involved in atherosclerosis pathogenesis. IgM antibodies against MDA-LDL have been generally regarded as protecting from atherosclerosis. In contrast, the role of...

Effect of Fc-γ Receptor Polymorphism on Rituximab-Mediated B Cell Depletion in ABO-Incompatible Adult Living Donor Liver Transplantation.

The affinity of IgG Fc receptor (FcγR) for rituximab, an anti-CD20 IgG1, differs based on single-nucleotide polymorphisms (SNPs) in FcγRs. This study aimed to explore the effect of such SNPs on clinical response to rituximab and outcomes in patients of ABO-incompatible (ABOi) living donor liver transplantation (LDLT). SNPs of FCGR2A[131H/R] and FCGR3A[158F/V], alleles encoding FcγR, were identified in 20 patients desensitized with rituximab before ABOi LDLT. The effect of these SNPs on B cell elimination and outcomes was analyzed in the patients. The isoform encoded by FCGR2A[131H/H] had a higher affinity for IgG1, and accordingly, the effects of rituximab on B cells were more profound in individuals with FCGR2A[131H/H] than in individuals with FCGR2A[131H/R or R/R]. Specifically, the time to B-cell reappearance in the peripheral blood was significantly delayed, and total serum IgM levels were significantly lower early after LDLT in individuals with FCGR2A[131H/H], even though these SNPs did not significantly affect the reduction of antiblood group A/B antibodies. The incidence of blood stream infection was also significantly higher in individuals with FCGR2A[131H/H], and this SNP was associated with poor prognosis. Despite no significant effect of FCGR3A[158F/V] on survival after ABOi liver grafts, the incidence of infection was significantly higher in individuals with FCGR3A[158F/V or F/F] than in individuals with FCGR3A[158V/V]. Our findings indicate FCGR SNPs influence the effect of rituximab on B-cell depletion and are possibly predisposing factors for infectious complications after ABOi LDLT. This study will be a good foundation for further studies on larger cohorts.

Partial protection from lupus-like disease in B-cell specific IFNAR-deficient B6.Nba2 mice

Abstract A majority of patients presenting with systemic lupus erythematosus (SLE) have increased serum concentrations of interferon alpha (IFNα). IFNα has previously been shown to affect lymphocyte activities such as B cell differentiation and T cell maintenance, but whether IFNα signaling specifically in B cells is required for disease pathology remains unknown. In order to examine the role of IFNα stimulation on B cells, we backcrossed mice lacking the IFNα receptor on B cells, Mb1.cre IFNARflx/flx, with the B6.Nba2 lupus mouse model. B6.Nba2.BΔIFNAR mice were evaluated alongside littermate control mice for splenomegaly, abnormal spleen subset distribution, IgG immune-complex deposition in the kidney glomeruli. Serum total IgM, total IgG and anti-chromatin IgG levels were determined monthly. BΔIFNAR mice display normal IgM and IgG levels, but decreased serum antinuclear autoantibody levels (p&amp;lt;0.05), while deposition of IgG immune complexes in kidney glomeruli was similar to that of control mice. Both spleen weight and total splenocyte number were found to be significantly decreased in BΔIFNAR mice (p&amp;lt;0.05). Analyses of spleen cell subsets at 4 months of age revealed a trend towards decreased plasma cells and GC B cells in spleens of BΔIFNAR mice. Despite IFNAR being removed from B cells only, we observed a shift in the balance of effector/memory to naïve CD4 T cells in BΔIFNAR mice. In summary, we found that B6.Nba2.BΔIFNAR mice were partly protected from lupus pathology including splenomegaly, autoantibody production and B cell hyperactivation. Most surprisingly, T cell activation appeared to be diminished in B6.Nba2.BΔIFNAR mice, suggesting that B cells play a central role as both APCs and ASCs in the B6.Nba2 mouse model of lupus.

Myeloid 12/15-LOX regulates B cell numbers and innate immune antibody levels in vivo

Background. The myeloid enzyme 12/15-lipoxygenase (LOX), which generates bioactive oxidized lipids, has been implicated in numerous inflammatory diseases, with several studies demonstrating an improvement in pathology in mice lacking the enzyme. However, the ability of 12/15-LOX to directly regulate B cell function has not been studied. Methods. The influence of 12/15-LOX on B cell phenotype and function, and IgM generation, was compared using wildtype (WT) and 12/15-LOX ( Alox15 -/-) deficient mice. The proliferative and functional capacity of splenic CD19 + B cells was measured in vitro in response to various toll-like receptor agonists. Results. WT and Alox15 -/- displayed comparable responses. However in vivo, splenic B cell numbers were significantly elevated in Alox15 -/- mice with a corresponding elevation in titres of total IgM in lung, gut and serum, and lower serum IgM directed against the 12/15-LOX product, 12-hydroxyeicosatetraenoic acid-phosphatidylethanolamine (HETE-PE). Discussion. Myeloid 12/15-LOX can regulate B cell numbers and innate immune antibody levels in vivo, potentially contributing to its ability to regulate inflammatory disease. Furthermore, the alterations seen in 12/15-LOX deficiency likely result from changes in the equilibrium of the immune system that develop from birth. Further studies in disease models are warranted to elucidate the contribution of 12/15-LOX mediated alterations in B cell numbers and innate immune antibody generation to driving inflammation in vivo.

Myeloid 12/15-LOX regulates B cell numbers and innate immune antibody levels in vivo.

Background. The myeloid enzyme 12/15-lipoxygenase (LOX), which generates bioactive oxidized lipids, has been implicated in numerous inflammatory diseases, with several studies demonstrating an improvement in pathology in mice lacking the enzyme. However, the ability of 12/15-LOX to directly regulate B cell function has not been studied. Methods. The influence of 12/15-LOX on B cell phenotype and function, and IgM generation, was compared using wildtype (WT) and 12/15-LOX (Alox15-/-) deficient mice. The proliferative and functional capacity of splenic CD19+ B cells was measured in vitro in response to various toll-like receptor agonists. Results. WT and Alox15-/- displayed comparable responses. However in vivo, splenic B cell numbers were significantly elevated in Alox15-/- mice with a corresponding elevation in titres of total IgM in lung, gut and serum, and lower serum IgM directed against the 12/15-LOX product, 12-hydroxyeicosatetraenoic acid-phosphatidylethanolamine (HETE-PE). Discussion. Myeloid 12/15-LOX can regulate B cell numbers and innate immune antibody levels in vivo, potentially contributing to its ability to regulate inflammatory disease. Furthermore, the alterations seen in 12/15-LOX deficiency likely result from changes in the equilibrium of the immune system that develop from birth. Further studies in disease models are warranted to elucidate the contribution of 12/15-LOX mediated alterations in B cell numbers and innate immune antibody generation to driving inflammation in vivo.