Elevated Antibody Research Articles

Elevated herpesvirus antibody levels linked to schizophrenia and bipolar disorder

IntroductionPrevious research has implicated herpes simplex virus 1 (HSV1) and cytomegalovirus (CMV) in severe mental illness (SMI) with conflicting results. Both pathogens have high universal seroprevalence, are neurotropic and after the primary infection typically establish a persistent latent infection with periodic reactivations. Increased immunoglobin G (IgG) concentrations are considered to be attributable to an increased infection severity with more frequent reactivations or host immune system alterations.ObjectivesWe assessed the HSV1 and CMV IgG concentrations in previously infected (seropositive) patients with SMI and healthy controls (HC). We hypothesized that seropositive patients would show higher IgG concentrations than seropositive HC.MethodsWe included 765 patients, 515 with schizophrenia (SZ) and 250 with bipolar disorder (BP), and 541 HC. HSV1 and CMV IgG seropositivity and concentrations were measured with immunoassays. 355 patients, mean age 33 years, 45% females, and 238 HC, mean age 35 years, 44% females, were HSV1 seropositive (HSV1+) while 447 patients, mean age 33 years, 50% females, and 296 HC, mean age 34 years, 47% females, were CMV seropositive (CMV+). In our main analysis among seropositive participants, we investigated the main effect of patient/control status on HSV1 and CMV IgG concentrations.ResultsThere were no significant differences in CMV or HSV1 seropositivity frequencies between patients with SZ, patients with BP and HC. Among seropositive participants, patients had higher HSV1 (p<0.001) and CMV (p=0.018) IgG concentrations than HC; stratifying by diagnosis, both patients with SZ (p=0.001) and patients with BP (p=0.001) had higher HSV1 IgG concentrations than HC, while patients with SZ, but not BP, had higher CMV (p=0.045) IgG concentrations than HC (Image). For HSV1, higher IgG concentrations were associated with higher general (p=0.017), negative (p=0.041) and positive (p=0.028) psychotic symptom scores.Image:ConclusionsSeropositive patients with SMI showed higher HSV1 and CMV IgG concentrations than seropositive HC suggesting that patients suffer a more severe infection or exhibit an altered immune response when contracting the pathogens. For HSV1, higher IgG concentrations were linked to more psychotic symptoms.Disclosure of InterestD. Andreou: None Declared, N. E. Steen: None Declared, K. N. Jørgensen: None Declared, T. Ueland: None Declared, L. Wortinger: None Declared, L. Mørch-Johnsen: None Declared, R. Yolken: None Declared, O. Andreassen Consultant of: Consultant to HealthLytix, Speakers bureau of: Received speaker’s honorarium from Lundbeck and Sunovion, I. Agartz Speakers bureau of: Received speaker’s honorarium from Lundbeck

(1254) - Characterization of Post-Transplant Clinical Outcomes in Patients with Elevated AT1R Antibodies Bridged to Heart Transplantation with Ventricular Assist Device

(1254) - Characterization of Post-Transplant Clinical Outcomes in Patients with Elevated AT1R Antibodies Bridged to Heart Transplantation with Ventricular Assist Device

Susceptibility, Immunity, and Persistent Infection Drive Endemic Cycles of Coxiellosis on Dairy Farms.

Coxiella (C.) burnetii, a zoonotic bacterium, is prevalent in dairy farms. Some cows develop a persistent infection and shed C. burnetii into milk and occasionally by amniotic fluid at calving. Serological diagnosis of Q fever in humans is performed by phase (Ph)-specific antibody tests; PhII antibodies usually indicate an acute infection, while the development of a chronic infection is characterised by elevated PhI antibody titres. Phase-specific tests have now been established for diagnosis of coxiellosis in cattle. Additionally, an interferon-γ (IFN-γ) recall assay has been implemented to assess cellular immunity to C. burnetii in cattle. Milk samples from all lactating cows (n = 2718) of 49 Bavarian dairy farms were collected through a convenience sample and analysed for phase-specific antibodies. Antibody profiles were evaluated by age. Based on the seropositivity of first-lactation cows, three distinct herd profiles were observed: an 'acute' state of herd infection was characterised by a PhI-/PhII+ pattern. The detection of PhI antibodies (PhI+/PhII+) characterised the 'chronic' state, and seronegative results defined the 'silent' state of herd infection. If antibodies had not been detected in multiparous cows, the herd was considered as probably free of coxiellosis. The analysed cattle herds were noted to have an 'acute' (n = 12, 24.5%), 'chronic' (n = 18, 36.8%), or 'silent' state of herd infection (n = 16, 32.6%). Only three farms (6.1%) were classified as 'free' of C. burnetii. The detection of these herd states over a time period of 4 years in one farm indicated that the described states occur in a cyclical manner. Frequently, a wave-like profile was seen, i.e., a circumscribed seronegative age group was flanked by seropositive age groups. In seronegative animals, IFN-γ reactivity was demonstrated. Seroconversion after vaccination was observed by day 7 post-vaccination in chronically infected herds, whereas in the case of silent infection, it started by day 14. These data indicated a pre-existing immunity in seronegative animals in chronically infected herds. Additionally, IFN-γ reactivity was detected in seronegative calves (>3 months) and heifers from chronically infected farms compared to a negative farm. An infection prior to 3 months of age resulted in cellular immunity in the absence of detectable antibodies. An infection around calving would explain this. The aforementioned circumscribed seronegative age groups are, therefore, explained by an infection early in life during active shedding at calving. Based on these results, an endemic cycle of coxiellosis is proposed: Susceptible young heifers get infected by persistently infected cows. Subsequently, shedding of C. burnetii at calving results in infection and then in cellular immunity in offspring. When these calves enter the cow herd two years later, a maximum of herd immunity is achieved, shedding ceases, and new susceptible animals are raised. In an acutely infected dairy farm, the PhI+/PhII+ serological pattern prevailed in second-lactation cows. In this study, stored sera collected since birth were analysed retrospectively. From the earliest seroconversion, the peak of seroconversion took about 33 months. These data suggested a slow spread of infection within herds. The classification of dairy cow herds is a promising basis for further analysis of the clinical impact of coxiellosis.

Field testing of recombinant subunit vaccines against Teladorsagia circumcincta in lambing ewes demonstrates a lack of efficacy in the face of a multi-species parasite challenge

IntroductionWe previously demonstrated efficacy of an 8-antigen recombinant subunit vaccine against a single species homologous Teladorsagia circumcincta challenge in lambs and in lambing ewes in pen trials. We subsequently demonstrated efficacy of a simplified, 2-antigen, version of this vaccine in lambs in pen trials. Here, we test both vaccines in lambing ewes in a field setting.MethodsIn the work presented here, 12 adjacent plots were seeded with a mixed infection of several common species of parasitic nematodes of sheep in temperate regions, including T. circumcincta. Ewes (n = 144), in groups of 12, grazed for 2 years on these plots and, in the first year, six of these groups of ewes were vaccinated with a 2-antigen prototype vaccine against T. circumcincta prior to mating and then again prior to lambing. In the following year these ewes were immunised again, this time with the 8-antigen prototype vaccine against T. circumcincta prior to mating and then prior to lambing. Throughout both seasons antigen-specific serum antibody levels in ewes and faecal worm egg counts (FEC) in ewes and their lambs were monitored, along with nematode species diversity at lambing.ResultsImmunised ewes produced elevated serum antibody levels to each of the vaccine antigens following immunisation but their FEC levels were not statistically significantly impacted by vaccination with either vaccine. FEC levels were also not impacted in lambs co-grazing the pastures with these immunised ewes. Nematode species diversity was not significantly impacted by vaccination in either year.DiscussionThe immunosuppressive effects of co-infecting gastrointestinal nematodes, the absence of vaccine cross-protection against co-infecting species and the influence of the periparturient relaxation in immunity probably all contributed to the inability of either vaccine to protect against T. circumcincta infection in field trials in the work presented here.

Amikacin Liposome Inhalation Suspension in the Real-World Management of Refractory Mycobacterium avium Complex Pulmonary Disease.

The increasing prevalence of Mycobacterium avium complex (MAC) pulmonary disease poses a significant therapeutic challenge, particularly due to the limited efficacy and systemic toxicity associated with conventional guideline-based therapy. Amikacin liposome inhalation suspension (ALIS) has been developed, yet its real-world application remains underreported. This retrospective analysis, conducted from March 2021 to February 2024, examined ALIS's clinical use in patients aged 20 years or older with refractory MAC pulmonary disease at our institution. The primary objective of this study is to describe the patient characteristics and clinical trajectories associated with the initiation of ALIS therapy in real-world settings for individuals diagnosed with MAC pulmonary disease. Of 11 patients initiated on ALIS, one was excluded due to financial constraints impacting continuation. The analysis proceeded with the remaining 10 subjects. The mean age of participants was 70.2 years, with a predominance of female patients (n = 7, 70%) and a higher incidence of M. avium infections (n = 6, 60%). Forty percent of the cohort (n = 4) had a history of ethambutol-induced optic neuritis leading to the cessation of the drug. The average interval from the initiation of guideline-based therapy to the start of ALIS was 8.5 ± 6.9 years (mean ± standard deviation). The majority (80%) presented with positive Gaffky scores at ALIS initiation, and a significant proportion exhibited resistance to clarithromycin and ethambutol. Comorbid conditions, including diabetes and previous cancer, were noted. The study also observed elevated anti-MAC antibody levels. Treatment duration varied, with fatigue leading to discontinuation in two cases. Treatment-emergent adverse events were documented in individual patients, each presenting with grade 1 severity: hemoptysis (n = 1, 10%), elevated creatinine levels (n = 1, 10%), and dysphonia (n = 2, 20%) were observed, respectively. Correlation analysis revealed a significant inverse relationship between body mass index (BMI) and ALIS discontinuation due to fatigue, and a positive correlation between Gaffky scores and C-reactive protein (CRP) levels. These results underscore the potential benefits and limitations of ALIS, suggesting that timely intervention and comprehensive healthcare support are crucial for optimal outcomes in the treatment of advanced MAC pulmonary disease.

Immunological Risk Factors in Recurrent Pregnancy Loss in Patients With Hereditary Thrombophilia.

Recurrent pregnancy loss (RPL) is a complicated reproductive disorder with underlying genetic and immunological causes. RPL may be influenced by hereditary thrombophilia, a class of blood clotting-related genetic abnormalities, via the vascular and immune systems. This study examines the immunological characteristics that hereditary thrombophilia patients have in common with RPL. A prospective cohort study included 300 patients split into two groups: a control group without hereditary thrombophilia and a group with the condition. Interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-γ)levels were measured, along with demographic specifics, antiphospholipid antibodies, natural killer (NK) cell counts, and other cytokines. Group differences were found using statistical analysis. Antiphospholipid antibodies were significantly more common in the thrombophilia group (42% testing positive, p=0.001) compared to the control group (12% testing positive), despite demographic factors being similar between groups (p=0.372 and p=0.093).When body mass index (BMI) was taken into account, the studyfound a statistically significant difference (p=0.046), with the thrombophilia group having a higher mean BMI (26.3 kg/m2, standard deviation (SD): 2.8) than the control group (24.7 kg/m2, SD: 3.1). IL-6(14.8 pg/mL, SD: 3.2, p=0.029) were higher than the control group (12.4 pg/mL,SD: 2.1), and TNF-α levels were higher in the thrombophilia group (10.5 pg/mL, SD: 2.0, p=0.012) compared to the control group (8.9 pg/mL,SD: 1.5), but NK cell counts did not differ significantly (p=0.213). This study emphasizes the role of elevated pro-inflammatory cytokines (IL-6 and TNF-α) and antiphospholipid antibodies in RPL among people with hereditary thrombophilia. In this population, early detection and immunomodulatory interventions may improve pregnancy outcomes. To fully comprehend these mechanisms and create customized treatments, collaborative research is required.

Antibody level comparison after porcine epidemic diarrhea vaccination via different immunization routes.

Porcine epidemic diarrhea (PED) is a disease extremely harmful to pig health. Intramuscular and Houhai acupoint injections are the main immunization routes to prevent and control PED. This study aimed to evaluate the efficacy of these two routes in pregnant sows based on serum IgG, IgA, and neutralizing antibody levels. PED virus (PEDV) immunoprophylaxis with live-attenuated and inactivated vaccines was administered. The vaccinations for the intramuscular injections elevated IgG and neutralizing antibody levels more than Houhai acupoint injections at most timepoints after immunization. However, the anti-PEDV IgA antibodies induced by vaccination with the two immunization routes did not differ significantly. In conclusion, intramuscular injections are better than Houhai acupoint injections for PEDV vaccination of pregnant sows.

Application of Recombinant Lactic Acid Bacteria (LAB) Live Vector Oral Vaccine in the Prevention of F4+ Enterotoxigenic Escherichia coli.

Enterotoxigenic Escherichia coli (ETEC) causes severe diarrhea in piglets. The current primary approach for ETEC prevention and control relies on antibiotics, as few effective vaccines are available. Consequently, an urgent clinical demand exists for developing an effective vaccine to combat this disease. Here, we utilized food-grade Lactococcus lactis NZ3900 and expression plasmid pNZ8149 as live vectors, together with the secreted expression peptide Usp45 and the cell wall non-covalent linking motif LysM, to effectively present the mutant LTA subunit, the LTB subunit of heat-labile enterotoxin, and the FaeG of F4 pilus on the surface of recombinant lactic acid bacteria (LAB). Combining three recombinant LAB as a live vector oral vaccine, we assessed its efficacy in preventing F4+ ETEC infection. The results demonstrate that oral immunization conferred effective protection against F4+ ETEC infection in mice and piglets lacking maternal antibodies during weaning. Sow immunization during late pregnancy generated significantly elevated antibodies in colostrum, which protected piglets against F4+ ETEC infection during lactation. Moreover, booster immunization on piglets during lactation significantly enhanced their resistance to F4+ ETEC infection during the weaning stage. This study highlights the efficacy of an oral LAB vaccine in preventing F4+ ETEC infection in piglets by combining the sow immunization and booster immunization of piglets, providing a promising vaccination strategy for future prevention and control of ETEC-induced diarrhea in piglets.

Engineering Antigen-Specific Tolerance to an Artificial Protein Hydrogel.

Artificial protein hydrogels are an emerging class of biomaterials with numerous prospective applications in tissue engineering and regenerative medicine. These materials are likely to be immunogenic due to their frequent incorporation of novel amino acid sequence domains, which often serve a functional role within the material itself. We engineered injectable "self" and "nonself" artificial protein hydrogels, which were predicted to have divergent immune outcomes in vivo on the basis of their primary amino acid sequence. Following implantation in mouse, the nonself gels raised significantly higher antigel antibody titers than the corresponding self gels. Prophylactic administration of a fusion antibody targeting the nonself hydrogel epitopes to DEC-205, an endocytic receptor involved in Treg induction, fully suppressed the elevated antibody titer against the nonself gels. These results suggest that the clinical immune response to artificial protein biomaterials, including those that contain highly antigenic sequence domains, can be tuned through the induction of antigen-specific tolerance.

Evaluation of different types of adjuvants in a malaria transmission-blocking vaccine

Adjuvants are critical components for vaccines, which enhance the strength and longevity of the antibody response and influence the types of immune response. Limited research has been conducted on the immunogenicity and protective efficacy of various adjuvants in malaria transmission-blocking vaccines (TBVs). In this study, we formulated a promising TBV candidate antigen, the P. berghei ookinete surface antigen PSOP25, with different types of adjuvants, including the TLR4 agonist monophosphoryl lipid A (MPLA), the TLR9 agonist cytosine phosphoguanosine oligodeoxynucleotides (CpG ODN 1826) (CpG), a saponin adjuvant QS-21, aluminum hydroxide (Alum), and two combination adjuvants MPLA + QS-21 and QS-21 + CpG. We demonstrated that adjuvanted vaccines results in elevated elicited antibody levels, increased proliferation of plasma cells, and efficient formation of germinal centers (GCs), leading to enhanced long-term protective immune responses. Furthermore, CpG group exhibited the most potent inhibition of ookinete formation and transmission-blocking activity. We found that the rPSOP25 with CpG adjuvant was more effective than MPLA, QS-21, MPLA + QS-21, QS-21 + CpG adjuvants in dendritic cells (DCs) activation and differentiation. Additionally, the CpG adjuvant elicited more rubust immune memory response than Alum adjuvant. CpG and QS-21 adjuvants could activate the Th1 response and promote the secretion of IFN-γ and TNF-α. PSOP25 induced a higher number of Tfh cells in splenocytes when combined with MPLA, CpG, and QS-21 + CpG; and there was no increase in these cell populations when PSOP25 was administered with Alum. In conclusion, CpG may confer enhanced efficacy for the rPSOP25 vaccine, as evidenced by the ability of the elicited antisera to induce protective immune responses and improved transmission-blocking activity.

Clinical Spectrum, Treatment and Outcome of Children with Autoimmune Encephalitis.

To assess the clinical spectrum, treatment, and outcome of children with autoimmune encephalitis (AE). Descriptive study. Place and Duration of the Study: Department of Paediatrics, The Aga Khan University Hospital, Karachi, Pakistan, from January 2017 to December 2021. Medical records of children with a diagnosis of AE were reviewed for clinical features, treatment details, and outcomes. Outcome was defined as good (0-2) or poor (3-6) based on a modified Rankin Scale (mRS) score at 3-month follow-up. Descriptive statistics were reported and logistic regression was used to assess the prognostic factors associated with outcome. Thirty-three patients were identified with AE. Thirteen (39.3%) were antibody positive. Anti-N-methyl-D-aspartate receptor (NMDAR) antibody was seen in 92% of positive cases. Behavioural abnormalities (87.8%), seizures (81.8%), movement disorders (66.6%), psychiatric symptoms (63.6%), and mutism (33.3%) were the prominent symptoms. Thirty (91%) patients received first-line immunotherapy. Good outcome was seen in 14 (48.2%) patients. Univariable analysis showed that the odds of having poor outcome were 2.5 (95% confidence interval [CI] 0.37-16.88, p=0.34) in patients with chorea. In addition, an elevated cerebrospinal fluid (CSF) protein had an odds ratio (OR) of 8.6 (CI 0.88-84.83, p=0.064) and positive CSF antibodies had an OR of 3.7 (CI 0.79-17.72, p=0.095) for a poor outcome. Mortality was seen in 4 (12.1%) patients. A very low threshold is needed for the diagnosis of AE in children presenting with behavioural symptoms and chorea. Although the odds for poor prognosis were higher in patients with chorea, elevated CSF protein and positive CSF antibodies, the p-value did not come out significant. Autoimmune encephalitis, Antibodies, NMDAR, Immunotherapies, mRS score, Outcome.

Nystagmus and Imbalance as the Presenting Symptoms of AntiGad Antibody Syndrome in A 67-Year-Old Female

Autoimmune encephalitis is a serious condition that causes brain inflammation, usually mediated by antibodies to various neuronal antigens [1]. One of the many antigens that may generate an immune response and cause this type of inflammation is the glutamic acid decarboxylase enzyme (GAD). AntiGAD (glutamic acid decarboxylase) antibodies are targeted against the GAD enzyme that converts glutamate to GABA, which is the nervous system’s primary inhibitory neurotransmitter [2]. With the body’s primary inhibitory neurotransmitter compromised, anti-GAD antibody syndrome is a rare type of autoimmune encephalitis that results in various symptoms related to prolonged excitation, such as seizures or nystagmus [3]. We present a rare case of autoimmune encephalitis caused by significantly elevated Anti-GAD antibody, with concomitant rheumatoid arthritis in the hands/wrists; symptoms of downbeat nystagmus, diplopia, headaches, and joint pain are improved with rituximab and IVIG infusion, following an unsuccessful treatment with oral prednisone.

Prevalence of viral infections in MS and ALS

Multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) are neurological diseases with complex etiologies, involving both genetic and environmental factors. Evidence suggests that viral infections may play a role in pathogenesis of these diseases. This review aims to summarize the current understanding of the prevalence of viral infections in MS and ALS. In MS, several viruses have been implicated, including Epstein-Barr virus, human herpesvirus 6, and varicella-zoster virus. Studies have reported elevated antibody titers against these viruses in MS patients compared to controls, suggesting a potential association between viral infections and MS risk. viral infections have been linked to MS relapses and disease progression, indicating a possible role in disease activation. In ALS, viral infections as enteroviruses and retroviruses have been investigated as potential triggers or contributors to disease pathogenesis. While the evidence linking viral infections to ALS is less robust than in MS, studies have reported associations between specific viral infections and ALS progression. Understanding the prevalence of viral infections in MS and ALS is crucial for unraveling the complex interplay between viruses and the immune system in these diseases. Further research is needed to elucidate the mechanisms by which viral infections may influence disease development and progression in MS and ALS, which could lead to the development of novel therapeutic strategies targeting viral pathways in these neurological disorders. This review briefly discusses the epidemiology and pathophysiology related alterations of Multiple sclerosis and Amyotrophic lateral sclerosis, and their immune responses highlighting the viral infections associated with these diseases.

Differential pulmonary toxicity and autoantibody formation in genetically distinct mouse strains following combined exposure to silica and diesel exhaust particles

BackgroundInhalation of airborne particulate matter, such as silica and diesel exhaust particles, poses serious long-term respiratory and systemic health risks. Silica exposure can lead to silicosis and systemic autoimmune diseases, while DEP exposure is linked to asthma and cancer. Combined exposure to silica and DEP, common in mining, may have more severe effects. This study investigates the separate and combined effects of occupational-level silica and ambient-level DEP on lung injury, inflammation, and autoantibody formation in two genetically distinct mouse strains, thereby aiming at understanding the interplay between genetic susceptibility, particulate exposure, and disease outcomes. Silica and diesel exhaust particles were administered to mice via oropharyngeal aspiration. Assessments of lung injury and host response included in vivo lung micro-computed tomography, lung function tests, bronchoalveolar lavage fluid analysis including inflammatory cytokines and antinuclear antibodies, and histopathology with particle colocalization.ResultsThe findings highlight the distinct effects of silica and diesel exhaust particles (DEP) on lung injury, inflammation, and autoantibody formation in C57BL/6J and NOD/ShiLtJ mice. Silica exposure elicited a well-established inflammatory response marked by inflammatory infiltrates, release of cytokines, and chemokines, alongside mild fibrosis, indicated by collagen deposition in the lungs of both C57BL/6J and NOD/ShilLtJ mice. Notably, these strains exhibited divergent responses in terms of respiratory function and lung volumes, as assessed through micro-computed tomography. Additionally, silica exposure induced airway hyperreactivity and elevated antinuclear antibody levels in bronchoalveolar lavage fluid, particularly prominent in NOD/ShiLtJ mice. Moreover, antinuclear antibodies correlated with extent of lung inflammation in NOD/ShiLTJ mice. Lung tissue analysis revealed DEP loaded macrophages and co-localization of silica and DEP particles. However, aside from contributing to airway hyperreactivity specifically in NOD/ShiLtJ mice, the ambient-level DEP did not significantly amplify the effects induced by silica. There was no evidence of synergistic or additive interaction between these specific doses of silica and DEP in inducing lung damage or inflammation in either of the mouse strains.ConclusionMouse strain variations exerted a substantial influence on the development of silica induced lung alterations. Furthermore, the additional impact of ambient-level DEP on these silica-induced effects was minimal.

Condiciones trombofilicas y su riesgo en una cohorte latinoamericana de gestantes, estudio observacional descriptivo

Objective: To evaluate thrombophilias associated with venous thromboembolism during pregnancy. Methods: Descriptive observational study. Clinical and laboratory alterations were analyzed, as well as the classification of the related profile of a cohort of Latin American pregnant women with thrombotic events during gestation and up to the 120-day puerperium. Antiphospholipid syndrome antibodies, coagulation protein C, S, antithrombin III, mutations against factor V Leiden, mutations in methylenetetrahydrofolate reductase, hyperhomocysteinemia, prothrombin mutation, and elevation of factors VIII, IX, and XI were performed. Results: The mean age was 24,5 + 7,6 years, of which 9 patients (10,3%) had a history of thromboembolism, 23 patients (26,4%) had had at least one fetal loss. Elevated antiphosphatidylserine antibodies were found in 23 patients (26,4%), elevated antibodies against beta2-glycoprotein in 20 patients (22,9%), positive lupus anticoagulant in 16 patients (18,3%), elevated factor VIII in 13 patients (14,94%), elevated factor IX in 15 patients (17,2%), elevated factor XI in 12 patients (13,7%), prothrombin mutation in 7 patients (8,07%) and the others to a lesser extent. Conclusions: The results found here point to the high prevalence rate of underdiagnosed thrombophilic disorders in pregnant women. There is still a lack of strong evidence to analyze this relationship with worse results during pregnancy. Keywords: Coagulation, Thrombosis, Gynecology.

Prevalence and Clinical Associations of Anti-C1q Antibodies in Paediatric Systemic Lupus Erythematosus in Indian Children

Background: Paediatric systemic lupus erythematosus (pSLE) is a heterogeneous, chronic autoimmune disease characterised by multi-system inflammation and the production of antibodies-directed self-antigens. Anti-C1q has been associated with SLE as well as other connective tissue diseases. They have been considered as a marker for disease activity and the presence of nephritis. Objectives: To determine the prevalence of anti-C1q antibodies in the paediatric SLE and to determine clinical associations of elevated anti-C1q antibody levels, especially with lupus nephritis. Methods: All consecutive children with SLE on treatment with immunosuppressive drugs attending our clinic were recruited. After obtaining informed consent, blood samples were tested for anti-C1q antibodies by a commercially available ELISA kit. The prevalence of anti-C1q and its association with lupus nephritis were determined. Results: Out of a total 150 children with SLE, anti-C1q positivity was present in 95 children (64%), at a cut-off value of 20 U/mL. Children with proteinuria, low C3, low C4 and anti-dsDNA positivity had significantly more anti-C1q antibody positivity. Children with lupus nephritis were significantly more likely to have anti-C1q antibody positivity than children without renal involvement (74% vs. 51%, p = .02). Among the children with lupus nephritis, children with active renal disease were more likely to have anti-C1q positivity than in children with quiescent disease (88% vs. 53%, p = .002). Anti-C1q antibodies had a sensitivity of 74% and specificity of 54% at a cut-off value of 22 U/L for renal disease in pSLE. Conclusion: In our study, children with lupus nephritis were significantly associated with elevated anti-C1q antibodies, and children with active renal disease had higher anti-C1q positivity than those with quiescent disease. Anti-C1q levels showed significant associations with low C3, low C4 and anti-dsDNA positivity. Anti-C1q levels did not show significant associations with clinical features of SLE like malar rash, arthritis and CNS involvement. Anti-C1q antibody titres were found to have a positive correlation with renal disease and hence could be used as an adjunctive biomarker in monitoring the disease activity in children with lupus nephritis.

Does parity order or cow antibody level influence the humoral immunity of calves for cattle anaplasmosis?

Anaplasmosis is a widely distributed vector-borne disease of cattle caused by the bacteria Anaplasma marginale, which may lead to severe losses in beef and dairy cattle production. Anecdotal information among farmers suggested that some cows may deliver calves more resilient to anaplasmosis. To investigate this, we tested two hypotheses: (i) whether the parity order or (ii) cow antibody levels may influence the humoral immunity of pre-weaning calves against cattle anaplasmosis. For this study, we sampled 170 cattle (Bos taurus taurus, Angus breed) on a farm in Southern Brazil, comprising 85 cows (50 multiparous and 35 primiparous) and their 85 calves (50days old). Antibodies against A. marginale were investigated using iELISA. Eighty percent of the animals were considered seropositive (100% of the cows and 60% of the calves). There was no significant difference in seroprevalence between calves from primiparous and multiparous cows. However, calves from multiparous cows exhibited higher antibody levels. To address the second question, we classified cows based on their antibody levels to A. marginale (high or low). Calves from cows with high antibody levels also showed elevated antibody levels against A. marginale. Furthermore, calves from cows with high antibody levels had approximately four times greater odds of being seropositive for A. marginale at 50days old than those born to mothers with low antibody levels. In conclusion, the calf's antibody level against A. marginale appears to be related to the cow's parity order and the mother's antibody level.

DOP27 Systemic antibody responses against gut microbiota flagellins implicate shared and divergent immune reactivity in Crohn's Disease and chronic fatigue syndrome

Abstract Background Patients with Crohn’s disease (CD) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) exhibit elevated antibody responses against gut microbiota flagellins. However, flagellin-specific antibody repertoires and functional roles in the diseases remain incompletely understood. Bacterial flagellins can be categorized into three types depending on their interaction with toll-like receptor 5 (TLR5): (1) "stimulator" and (2) "silent" flagellins, binding TLR5 through a conserved N-terminal motif, with only stimulators activating TLR5 due to a specific C-terminal domain; (3) "evader" flagellins of pathogens, which circumvent TLR5 activation via mutated N-terminal TLR5 binding motifs. Here we studied the characteristics, epitope binding, and sequence (dis)similarity of anti-flagellin antibody responses in CD and ME/CFS. Methods Since conventional antibody profiling methods like enzyme-linked immunosorbent assays [ELISAs] do not allow for large-scale measurements of antibody repertoires, we leveraged phage-display immunoprecipitation sequencing (PhIP-Seq) to characterize 344,000 rationally selected peptide antigens in 256 patients with CD, 40 patients with ME/CFS and in two equally sized groups of age- and sex-matched healthy controls from population-based cohorts in the Netherlands and U.K., respectively. Different sequence alignment strategies were employed to compare flagellin peptide structures with observed antibody-bound flagellin peptide reactivity. Results Both patients with CD and ME/CFS exhibited elevated antibody responses against distinct regions of flagellin peptides compared to healthy individuals (P<0.001). N-terminal binding to Lachnospiraceae flagellins was comparable in both diseases, while C-terminal binding was more prevalent in CD. N-terminal antibody-bound flagellin sequences were similar across CD and ME/CFS, resembling ‘stimulator’ and ‘silent’ flagellins more than evaders. However, C-terminal antibody-bound flagellins showed higher resemblance to stimulator than to silent flagellins in CD, but not in ME/CFS. This group of antibody-bound flagellins was exclusively identified in a subset (10-20%) of patients with CD and characterized by its strong overrepresentation (exceeding 20-fold), underscoring its potential significance in distinguishing pathophysiologic subtypes of CD. Conclusion Antibody binding to the N-terminal domain of stimulator and silent flagellins may impact TLR5 activation in both CD and ME/CFS patients. Furthermore, elevated antibody binding to the C-terminal domain of stimulator flagellins in CD may explain pathophysiological differences between diseases. Our results highlight the diagnostic potential of these antibody responses and their impact on innate/adaptive immunity balance.

P193 Fatigued patients with Inflammatory Bowel Disease exhibit distinct systemic antibody epitope repertoires

Abstract Background Patients with inflammatory bowel diseases (IBD) frequently experience fatigue, affecting up to 80% of those with active disease and approximately 50% with quiescent disease. The exact cause of IBD-associated fatigue is often unknown, making clinical management very challenging. In this study we aimed to explore whether patients with quiescent IBD reporting fatigue exhibit specific systemic antibody responses, which could provide insight into immune reactivities underlying fatigue. Methods Systemic antibody epitope repertoires were profiled in 327 patients with IBD (156 Crohn’s disease [CD]; 171 ulcerative colitis [UC]) leveraging phage-display immunoprecipitation sequencing (PhIP-Seq) against 344,000 rationally selected peptide antigens. Fatigue severity was assessed on a 10-point Likert scale, ranging from 1 (no fatigue) to 10 (highest fatigue severity). Quiescent IBD was defined as clinical (Harvey-Bradshaw Index [HBI] <5 or Simple Clinical Colitis Activity Index [SCCAI] <2.5) and biochemical remission (C-reactive protein [CRP] <5 mg/L) at time of sampling. Multivariable logistic regression analyses, allowing adjustment for potential confounding factors e.g. age, sex, and smoking, were performed to identify associations between fatigue and systemic antibody responses. Results A total of 105 different antibody-bound peptides were associated with fatigue (nominal P-value<0.05), albeit none passed adjustment for multiple comparisons. Among these antibodies, 50 (47.6%) were found to be less frequent in highly fatigued patients (fourth quartile, Q4), while 55 (52.4%) were identified as more frequent in highly fatigued patients compared to those with low fatigue scores (first quartile, Q1). Among highly fatigued patients, antibody responses were primarily directed towards viral antigens, notably several antigens from Epstein-Barr virus (EBV), as well as bacterial antigens, including functional proteins from Streptococcus and Staphylococcus species. Fatigued patients with CD exhibited elevated systemic antibody responses against allergens, Staphylococcus, Pseudomonas aeruginosa, and Shigella spp. Fatigued patients with UC showed higher frequencies of antibody responses against herpes simplex virus (HSV), influenza viruses, and few responses against allergens and Streptococcus bacteria. These results remained materially unchanged when repeating analyses in patients with quiescent IBD. Conclusion This study may suggest a potential role of viral antigens, particularly EBV, in the pathophysiology of fatigue in patients with IBD. However, larger confirmatory studies are needed to validate these findings. PhIP-Seq may represent a valuable strategy to approach the investigation of immune responses underlying complex symptoms such as fatigue.

DOP20 Changes in systemic antibody epitope repertoires from preclinical to established Inflammatory Bowel Disease

Abstract Background Inflammatory bowel diseases (IBD), encompassing Crohn's disease (CD) and ulcerative colitis (UC), exhibit unique immunological changes early in development. Although >300 IBD-specific antibody responses have been identified1, systemic antibody epitope repertoires of preclinical IBD remain elusive. This study aimed to profile systemic antibody responses at unprecedented depth in individuals before and after the onset of IBD, aiming to identify preclinical disease biomarkers. Methods This study included individuals participating in the Lifelines Cohort Study, a large prospective population-based cohort study in the Netherlands including 167,000 individuals with longitudinal follow-up. Participants without IBD at baseline were screened for any reported IBD diagnosis during follow-up (2006-2021). Individuals who reported IBD during follow-up and with available serum samples were included. Samples at baseline (pre-diagnosis) and during follow-up (post-diagnosis) were used to profile antibody repertoires against 344,000 rationally selected microbial-, food-, and immune antigens using phage-display immunoprecipitation sequencing (PhIP-Seq). Results A total of 178 individuals with new-onset IBD were identified (Fig. 1). Median follow-up time until diagnosis was 3.9 (IQR: 3.4-4.3) years. Most individuals reported newly developed UC (n=123, 69.1%), followed by CD (n=44, 24.7%), and undetermined IBD (IBD-U, n=11, 6.2%). A total of 5,174 antibody responses were observed in 5-95% of participants. Fifty-nine antibodies were differentially abundant (FDR<0.05) pre-diagnosis vs. post-diagnosis (Fig. 2), 14 of which (24%) were previously reported as IBD-specific1. Thirteen were more (22%) and 46 less (78%) frequently observed post-diagnosis. Those developing UC exhibited 33 differentially abundant antibody responses, while those with CD exhibiting only four (FDR<0.05). Individuals developing IBD exhibited lower frequencies of antibody responses against EBV-associated peptides post-diagnosis, e.g. Epstein-Barr nuclear antigen-1 (EBNA-1) and capsid protein V26, and varicella-zoster virus, alongside higher antibody responses against bacterial flagellins. Individuals developing UC showed elevated antibody responses mainly against viruses (e.g. human adenovirus C, enteroviruses B/C) and particular pathogenic bacterial species (e.g. pneumococcal histidine triad proteins) post-diagnosis compared to pre-diagnosis. Conclusion Distinct antibody responses appear years before IBD diagnosis, indicating potential involvement in pre-clinical disease development. Furthermore, post-diagnosis, lower frequencies of antibody responses against EBV may suggest reduced immunogenicity against this virus in early disease pathogenesis. 1. Bourgonje et al. Immunity. 2023.