Increase In IgG Titers Research Articles

Oral Chagas disease outbreak by bacaba juice ingestion: A century after Carlos Chagas' discovery, the disease is still hard to manage.

Orally transmitted acute Chagas disease (ACD) primarily affects low-visibility and low-income individuals in tropical and subtropical zones. Managing ACD remains challenging even after more than 100 years of its discovery. Its spread to non-endemic areas has made it a global health issue. The aim of this work is to demonstrate the difficulties encountered in handling a real-life situation. This report examines an outbreak of 39 cases of ACD due to oral transmission by bacaba juice ingestion that occurred in Pedro do Rosário, Maranhão, Brazil. A clinical and epidemiological investigation, including an entomological search, was conducted. Diagnosis criteria included positive peripheral blood smear (PBS), seroconversion of IgG, and a two-fold increase in IgG titer (laboratory criteria); and clinical findings, epidemiological exposure, and at least one positive IgG test (clinical-epidemiological criteria). In-house conventional polymerase chain reaction (PCR) was performed on 33 samples. All patients were treated with benznidazole. After 4.5 years, IgG levels were reassessed in 26 individuals. The mean age was 33.6 years, with no gender difference. The mean incubation period was 13.8 days, and the mean between symptom onset and treatment was 16.6 days. The most common symptoms were fever and lymphadenopathy (90%). Diagnostic success rates were 66.6% (laboratory criteria), 23% (clinical-epidemiological criteria), and 10.2% (high clinical suspicion despite negative tests). Test positivity rates were 69.7% (PBS), 91.4% (serology), and 100% (PCR). There were no deaths. Serological cure was achieved in 34.6% of cases, and IgG titers decreased in 15.3%. We encountered several barriers in managing ACD, including population vulnerability, reliance on outdated diagnostic techniques, lack of standardized molecular biology methods, and limited therapeutic options. This report underscores the importance of rapid surveillance and early treatment to prevent fatalities. We recommend the standardization of conventional PCR in diagnostic routines.

Ala-Cys-Cys-Ala dipeptide dimer alleviates problematic cysteine and cystine levels in media formulations and enhances CHO cell growth and metabolism

Cysteine and cystine are essential amino acids present in mammalian cell cultures. While contributing to biomass synthesis, recombinant protein production, and antioxidant defense mechanisms, cysteine poses a major challenge in media formulations owing to its poor stability and oxidation to cystine, a cysteine dimer. Due to its poor solubility, cystine can cause precipitation of feed media, formation of undesired products, and consequently, reduce cysteine bioavailability. In this study, a highly soluble cysteine containing dipeptide dimer, Ala-Cys-Cys-Ala (ACCA), was evaluated as a suitable alternative to cysteine and cystine in CHO cell cultures. Replacing cysteine and cystine in basal medium with ACCA did not sustain cell growth. However, addition of ACCA at 4 mM and 8 mM to basal medium containing cysteine and cystine boosted cell growth up to 15% and 27% in CHO-GS and CHO–K1 batch cell cultures respectively and led to a proportionate increase in IgG titer. 13C-Metabolic flux analysis revealed that supplementation of ACCA reduced glycolytic fluxes by 20% leading to more efficient glucose metabolism in CHO–K1 cells. In fed-batch cultures, ACCA was able to replace cysteine and cystine in feed medium. Furthermore, supplementation of ACCA at high concentrations in basal medium eliminated the need for any cysteine equivalents in feed medium and increased cell densities and viabilities in fed-batch cultures without any significant impact on IgG charge variants. Taken together, this study demonstrates the potential of ACCA to improve CHO cell growth, productivity, and metabolism while also facilitating the formulation of cysteine- and cystine-free feed media. Such alternatives to cysteine and cystine will pave the way for enhanced biomanufacturing by increasing cell densities in culture and extending the storage of highly concentrated feed media as part of achieving intensified bioproduction processes.

Reduction of adverse reactions and correlation between post-vaccination fever and specific antibody response across successive SARS-CoV-2 mRNA vaccinations

BackgroundSARS-CoV-2 mRNA vaccination, recognized for high immunogenicity, frequently induces adverse reactions, especially fever. We previously reported a correlation between post-vaccination fever and specific antibody responses to the primary series and first booster. We herein report changes in adverse reactions and the correlation between post-vaccination fever and antibody responses across successive vaccinations, from monovalent to bivalent mRNA vaccines. MethodsThis cohort study was conducted at a Japanese hospital to investigate adverse reactions to the monovalent primary, first booster, and BA.4/5 bivalent BNT162b2 vaccinations. Local and systemic reactions were reported through a self-reporting diary after each dose. The spike-specific IgG titers were measured following each vaccination. ResultsAcross 727 vaccinations in the vaccine series, the bivalent booster induced fewer adverse reactions than earlier doses. Fever ≥ 38.0 °C was significantly less frequent in the bivalent booster (12.3 %) compared to the primary series and monovalent booster (22.0 %, 26.2 %, p < 0.001). Reaction severity was also reduced in the bivalent booster. In the analysis of 70 participants with complete data for all doses, post-vaccination fever ≥ 38.0 °C exhibited the highest relative risk (RR) among all solicited reactions throughout the vaccine series (RR: 5.24 [95 % CI: 2.40–11.42] for monovalent and 6.24 [95 % CI: 2.14–18.15] for bivalent). The frequency of fever ≥ 38.0 °C after all doses was 8.6 % (6/70), with no fever ≥ 39.0 °C across all vaccinations. A high-grade post-vaccination fever was correlated with higher IgG titers, with multivariate analyses confirming this correlation as independent for each dose and unaffected by previous post-vaccination fever. ConclusionsThe bivalent mRNA vaccine booster showed fewer and milder adverse reactions than the monovalent doses. Although vaccinees with a history of post-vaccination fever were more likely to experience fever after a subsequent dose, such recurrences were infrequent. A correlation between post-vaccination fever and increased IgG titers was identified for each vaccination, irrespective of post-vaccination fever history.

Gonadal androgens are associated with decreased type I interferon production by plasmacytoid dendritic cells and increased IgG titres to BNT162b2 following co-vaccination with live attenuated influenza vaccine in adolescents.

mRNA vaccine technologies introduced following the SARS-CoV-2 pandemic have highlighted the need to better understand the interaction of adjuvants and the early innate immune response. Type I interferon (IFN-I) is an integral part of this early innate response that primes several components of the adaptive immune response. Women are widely reported to respond better than men to tri- and quadrivalent influenza vaccines. Plasmacytoid dendritic cells (pDCs) are the primary cell type responsible for IFN-I production, and female pDCs produce more IFN-I than male pDCs since the upstream pattern recognition receptor Toll-like receptor 7 (TLR7) is encoded by X chromosome and is biallelically expressed by up to 30% of female immune cells. Additionally, the TLR7 promoter contains several putative androgen response elements, and androgens have been reported to suppress pDC IFN-I in vitro. Unexpectedly, therefore, we recently observed that male adolescents mount stronger antibody responses to the Pfizer BNT162b2 mRNA vaccine than female adolescents after controlling for natural SARS-CoV-2 infection. We here examined pDC behaviour in this same cohort to determine the impact of IFN-I on anti-spike and anti-receptor-binding domain IgG titres to BNT162b2. Through flow cytometry and least absolute shrinkage and selection operator (LASSO) modelling, we determined that serum-free testosterone was associated with reduced pDC IFN-I, but contrary to the well-described immunosuppressive role for androgens, the most bioactive androgen dihydrotestosterone was associated with increased IgG titres to BNT162b2. Also unexpectedly, we observed that co-vaccination with live attenuated influenza vaccine boosted the magnitude of IgG responses to BNT162b2. Together, these data support a model where systemic IFN-I increases vaccine-mediated immune responses, yet for vaccines with intracellular stages, modulation of the local IFN-I response may alter antigen longevity and consequently improve vaccine-driven immunity.

Risedronate-functionalized manganese-hydroxyapatite amorphous particles: A potent adjuvant for subunit vaccines and cancer immunotherapy

The cGAS-STING pathway and the Mevalonate Pathway are druggable targets for vaccine adjuvant discovery. Manganese (Mn) and bisphosphonates are known to exert adjuvant effects by targeting these two pathways, respectively. This study found the synergistic potential of the two pathways in enhancing immune response. Risedronate (Ris) significantly amplified the Mn adjuvant early antibody response by 166-fold and fortified its cellular immunity. However, direct combination of Mn2+ and Ris resulted in increased adjuvant toxicity (40% mouse mortality). By the combination of doping property of hydroxyapatite (HA) and its high affinity for Ris, we designed Ris-functionalized Mn-HA micro-nanoparticles as an organic-inorganic hybrid adjuvant, named MnHARis. MnHARis alleviated adjuvant toxicity (100% vs. 60% survival rate) and exhibited good long-term stability. When formulated with the varicella-zoster virus glycoprotein E (gE) antigen, MnHARis triggered a 274.3-fold increase in IgG titers and a 61.3-fold surge in neutralization titers while maintaining a better long-term humoral immunity compared to the aluminum adjuvant. Its efficacy spanned other antigens, including ovalbumin, HPV18 VLP, and SARS-CoV-2 spike protein. Notably, the cellular immunity elicited by the group of gE + MnHARis was comparable to the renowned Shingrix®. Moreover, intratumoral co-administration with an anti-trophoblast cell surface antigen 2 nanobody revealed synergistic antitumor capabilities. These findings underscore the potential of MnHARis as a potent adjuvant for augmenting vaccine immune responses and improving cancer immunotherapy outcomes.

Evaluation of Biodegradable Microparticles for Mucosal Vaccination Against Diphtheria Toxoid: Nasal Efficacy Studies in Guinea Pigs.

In this study, poly-(ɛ-caprolactone) (PCL) and poly-(lactic-co-glycolic acid) (PLGA) microparticles encapsulating diphtheria toxoid (DT) were investigated for their potential as a mucosal vaccine delivery system. Antigen-containing microparticles were prepared using the double emulsion (w/o/w) solvent evaporation method. The average geometric diameter of the particles was found to be between 7 and 24 µm, which is suitable for uptake by the antigen-presenting cells in the nasal mucosa. Although the differences were insignificant, the PLGA polymer-containing formulations exhibited the highest encapsulation efficiency. Microparticle formulations, prepared with both PLGA and PCL polymers, were successfully produced at high production yields. The in vitro release profile was presented as a biexponential process with an initial burst effect due to the release of the protein adsorbed on the microsphere surface, and the subsequent sustained release profile is the result of protein diffusion through the channels or pores formed in the polymer matrix. DT-loaded microparticles, DT solution in phosphate-buffered saline (PBS), and empty microparticles (control) were administered via nasal route and subcutaneously to guinea pigs. The antibody content of each serum sample was determined using an enzyme-linked immunosorbent assay (ELISA). Absorbance values of the ELISA test showed that PLGA- and PCL-bearing microparticles could stimulate an adequate systemic immune response with intranasal vaccination. In addition, PLGA and PCL microparticles resulted in significantly increased IgG titers with intranasal administration as a booster dose following subcutaneous administration. PCL polymer elicited a high immune response compared with PLGA polymer (p <0.05).

Correlation between specific antibody response to wild-type BNT162b2 booster and the risk of breakthrough infection with omicron variants: Impact of household exposure in hospital healthcare workers

BackgroundThe emergence of omicron variants exhibiting antigenic changes has led to an increase in breakthrough infection among individuals with a wild-type SARS-CoV-2 vaccine booster. The correlation between post-booster spike-specific antibodies and omicron infection risk remains unclear. MethodsThis prospective cohort study included SARS-CoV-2-naive healthcare workers with three-dose BNT162b2. Post-booster spike-specific IgG and interferon-γ levels were measured. Breakthrough infection was documented during a 10-month omicron-predominant period. Household and healthcare contacts were followed to identify subsequent infections. The IgG titers were additionally measured at the end of follow-up, and the titers at exposure were estimated from the two-point titers. ResultsOf 333 participants, 89 developed infection, of whom 37 (41.6 %) were household contacts. Kaplan-Meier curves indicated that higher IgG titers were significantly correlated with lower cumulative infection incidence (p = 0.029), whereas the interferon-γ levels were not (p = 0.926). Multivariate Cox analysis showed that increasing IgG titers were associated with a reduced hazard ratio (HR) of 0.26 (95% CI, 0.12–0.55). Household exposure posed a greater infection risk than healthcare exposure (HRs, 11.24 [6.88–18.40] vs. 2.82 [1.37–5.44]). The difference in geometric mean IgG titers of infected and uninfected participants was significant among household contacts (20,244 AU/mL vs. 13,842 AU/mL, p = 0.031). Estimation of IgG titers at exposure showed a significantly higher infection incidence in those exposed with titers of <3,000 AU/mL than in those with higher titers (79.2 % vs. 32.3 %, p < 0.001). ConclusionsSpike-specific antibodies induced by a wild-type SARS-CoV-2 vaccine booster are suggested to be effective in protecting against omicron infection. Household exposure would be a significant source of infection for hospital healthcare workers.

COVID-19 induced remission of biliary and renal cell carcinomas.

e14598 Background: Clear cell renal carcinoma and cholangiocarcinoma are resistant to standard therapy. Complete remissions are rare. SARS-CoV-2 (COVID-19) boosts anti-viral immune responses but effects on cancers are unknown. Case reports of hematologic cancer remissions after COVID infection are emerging. Anti PD1/PD-L1 antibody therapy have prolonged remission in 20% of solid tumor patients. mRNA COVID-19 vaccines and COVID-19 active infections create anti-viral immune responses - increased IgG titers, SARS-CoV-2-specific antibodies, and boost T-cell response. Anti PD-1/PD-L1 antibodies immune responses, are presumed independent of the immune response to COVID vaccination/infection. Two previous case reports of hematologic remission were seen after COVID infection. (Hodgkins, multiple myeloma). There are no cases of solid cancer remission after COVID-19 exposure. Methods: Three patients with solid cancers and complete/near complete radiographic remissions after COVID-19 exposure. Two on low carbohydrate diets. History, dietary course and clinical outcomes are presented. Results: Case 1: 58 year old male diagnosed with stage IV clear cell renal carcinoma (lung nodules, mediastinal nodes). After 5 years he progressed on Sunitinib and began Nivolumab. His cancer stabilized but hypophysitis, diarrhea, severe jaw pain ended his treatment. After COVID-19 booster vaccine, he became anorexic, lost 50 lbs over 8 weeks (267 to 211 lb). Relapse was suspected but PET CT showed complete resolution of his lung nodules and adenopathy. Asymptomatic and in remission over 9 months post vaccine. Case 2: 51 year old male heavily pretreated stage 4 renal cell cancer, bone, liver, nodal metastases. On Nivolumab with stable disease but after COVID booster vaccine had high fever, fatigue, myalgia. PET CT scans later showed near complete resolution of his bony, hepatic and nodal metastatic sites. Case 3: 75 year old male with unresectable cholangiocarcinoma on second line Atezolizumab. COVID-19 infection was followed by complete radiographic remission. Conclusions: Effects of SARS-CoV-2 (COVID-19) on cancers remain unknown. Few case reports of cancer remissions after infections are emerging. These are two cases of renal cell cancers in complete remission after COVID-19 vaccination while on immunotherapy. Both followed low glycemic diets. Third case was a complete remission of biliary cancer after an acute COVID-19 infection. Proposed anti-cancer mechanisms - pathogen specific T cell action, anti-inflammatory effects against COVID-19 infection, cross-reactivity against tumor antigens, natural killer cell activation. COVID-19 proteins have oncolytic properties - HIV related B cell apoptosis and Coxsackievirus A21 oncolytic effects on myeloma and CD138+ plasma cells via intercellular adhesion molecule interaction. COVID-19’s effects plus the anti PD-1/PD-L1 antibodies immune response may be synergistic and merits further research.

Impact of vaccine hesitancy on antibody response after SARS-CoV-2 vaccination in patients with cancer.

e18719 Background: An influence of various psychological factors (e.g., stress or vaccine hesitancy) on antibody response following vaccinations (vac; e.g. influenza, diphteria) has previously been reported. However, these are the first data on vaccine hesitancy’s impact on SARS-CoV-2 vac in a cohort of cancer patients (pts). Methods: Cancer pts at our university oncology center were prospectively enrolled between 01/2021-02/2022. Medical data and blood samples were collected at time of enrollment and before and after every SARS-CoV-2 vac, at 3 and 6 months. Anti-SARS-CoV-2 IgG levels and neutralizing antibodies (nAb) were determined. Pts also completed a questionnaire containing eleven-level Likert items ranging from 1 (“totally disagree”) to 11 (“totally agree”) regarding their attitude towards COVID-19 and vac in general. Results: Samples and questionnaires from 148 pts (41% female) were collected. Mean age was 64 (24-87) years. Most patients suffered from solid tumors (85%), mainly gastrointestinal (GI) cancer (59%), and were on active therapy (92%), mainly chemotherapy (80%). Agreement with “I am against vac in general” was significantly correlated with decreased SARS-CoV-2 IgG titers following first vac (ρ = -0.411, p = 0.018), second vac (ρ = -0.399, p = 0.044) and at 3 months follow-up (ρ = -0.293, p = 0.007) as well as reduced nAb after second vac (ρ = -0.533, p = 0.005) and 3 months (ρ = -0.221, p = 0.043). In contrast, stating “I will definitely get vaccinated against COVID-19” was strongly correlated with increased IgG titers following second vac (ρ = 0.44, p = 0.025). Also, “everyday stress will keep me from getting vaccinated” was significantly associated with decreased IgG and nAb following second vac (ρ = -0.433, p = 0.027; ρ = -0.391, p = 0.048). Multivariate linear regression (MLR) revealed being “against vac in general” as an independent negative predictor of IgG levels after first SARS-CoV-2 vac (β = -0.437, p = 0.022) and at 3 months follow-up (β = -0.292, p = 0.007). Among pts with GI cancer, agreement with “being afraid of vac side effects (SE)” demonstrated significantly decreased IgG (ρ = -0.334, p = 0.025) and nAb titers (ρ = -0.424, p = 0.004) after 3 months. MLR indicated fear of vac SE as an independent negative predictor of nAb after 3 months in this subgroup (β = -0.355, p = 0.025). Additionally, fear of SE was negatively correlated with anti-SARS-CoV-2 antibodies after second vac (ρ = -0.515, p = 0.029) and 3 months in male (ρ = -0.368, p = 0.011), but not in female pts. However, agreement with “I am completely confident that the vac are safe” was only correlated with increased IgG titers at 3 months follow-up in women (ρ = -0.361, p = 0.031). Conclusions: The current study revealed vaccine hesitancy’s significant negative impact on immune response following SARS-CoV-2 vac in cancer pts. Increased efforts to fight vaccine hesitancy are necessary to not only enhance vac coverage but also immune response among cancer pts.

Generation of polystyrene-specific antibodies for developing immunoassays to analyze microplastics and nanoplastics

Micro- and nano-plastics (MNPs) are emerging pollutants that have drawn worldwide attention due to their negative impacts on the health and sustainability of our ecosystem. Quantitative analysis of MNPs, especially those at nano-scale, is still challenging due to lack of efficient analytical methods. Different antibody-based immunoassay platforms have been well established and readily available for rapid, specific, and quantitative analysis of targets with a broad size range. The key to developing immunoassays for MNP analysis is to generate plastic-specific antibodies, which is still lacking. In this study, we conjugated the nanoparticles of polystyrene (PS), a widely studied representative MNPs, to different carrier proteins for rabbit immunizations. The PS-specific antibodies were significantly induced upon immunization (up to 128-fold increase in IgG titer), which was validated by multi-tier immunoassays using different PS products. Notably, the PS-specific antibodies did not react with polypropylene, a different plastic. Using PS antibody-based enzyme-linked immunoassay, we further demonstrated suitability of the antibody-based immunoassay for quantitative analysis of the PS particles that have been exposed to diverse matrices. Together, this study, for the first time, demonstrates the feasibility of producing plastic-specific antibodies, and lays the groundwork to develop innovative antibody-based immunoassays for future risk assessment and management of MNPs, particularly those at nano-scale.

An Integrated In Vivo/In Vitro Protein Production Platform for Site-Specific Antibody Drug Conjugates

The XpressCF+® cell-free protein synthesis system is a robust platform for the production of non-natural amino acids containing antibodies, which enable the site-specific conjugation of homogeneous antibody drug conjugates (ADCs) via click chemistry. Here, we present a robust and scalable means of achieving a 50-100% increase in IgG titers by combining the high productivity of cell-based protein synthesis with the unique ability of XpressCF+® reactions to produce correctly folded and assembled IgGs containing multiple non-natural amino acids at defined positions. This hybrid technology involves the pre-expression of an IgG light-chain (LC) protein in a conventional recombinant E. coli expression system, engineered to have an oxidizing cytoplasm. The prefabricated LC subunit is then added as a reagent to the cell-free protein synthesis reaction. Prefabricated LC increases IgG titers primarily by reducing the protein synthesis burden per IgG since the cell free translation machinery is only responsible for synthesizing the HC protein. Titer increases were demonstrated in four IgG products in scales ranging from 100-µL microplate reactions to 0.25-L stirred tank bioreactors. Similar titer increases with prefabricated LC were also demonstrated for a bispecific antibody in the scFvFc-FabFc format, demonstrating the generality of this approach. Prefabricated LC also increases robustness in cell-free reactions since it eliminates the need to fine-tune the HC-to-LC plasmid ratio, a critical parameter influencing IgG assembly and quality when the two IgG subunits are co-expressed in a single reaction. ADCs produced using prefabricated LC were shown to be identical to IgGs produced in cell-free alone by comparing product quality, in vitro cell killing, and FcRn receptor binding assays. This approach represents a significant step towards improving IgG titers and the robustness of cell-free protein synthesis reactions by integrating in vivo and in vitro protein production platforms.

Diagnostics and treatment of ocular toxoplasmosis : Results of a survey

Ocular toxoplasmosis (OT) is the most common infectious cause of posterior uveitis. This survey aimed to evaluate the current diagnostic and therapeutic approach to OT in Germany. Adetailed questionnaire with specific patient examples was sent in July 2021 to the members of the Uveitis Section of the German Ophthalmological Society (DOG) and the Retinological Society (RG). The questionnaire was answered by 53 (29RG and 24DOG) ophthalmologists. Of the respondents 16 (30%) work in private practice, 18 (34%) in aclinical facility and 19 (36%) in university hospital, 9 (17%) colleagues see < 50, 28 (53%) 50-200 and 16 (30%) more than 200 uveitis patients per year. The clinical results are still the gold standard (87%) for the diagnosis of OT and in cases of first manifestation 60% are supported by serological antibody investigations, while 10out of 53 (19%) ophthalmologists rely on the clinical presentation only. An IgM test is requested by 25 (47%) respondents, 6 expected an increase in IgG titer (11%) and 1 the detection of specific IgA antibodies (2%). The majority (n = 28, 53%) of ophthalmologists would aim at confirming the diagnosis by an anterior chamber puncture, from which 20(38%) prefer PCR, 3(6%) determination of Goldmann-Witmer coefficients (GW) and 5(9%) acombination of both methods. Clindamycin was most frequently used for treatment (n = 21, 40%), followed by pyrimethamine/sulfadiazine (n = 17, 32%) and trimethoprime + sulfamethoxazole (TMP/SMX) (n = 10, 19%); the latter was also used (n = 40, 75%) for secondary prophylaxis. The results show that apart from the clinical results as the gold standard for the diagnosis, there is no uniform approach to diagnosis and treatment of OT. The high request rate for serum IgM antibodies indicates awidespread uncertainty about the importance of serological findings. This should be viewed critically, given the continued high seroprevalence in Germany.

Immunological Effects of Dimethyldioctadecylammonium Bromide and Saponin as Adjuvants for Outer Membrane Vesicles from Neisseria meningitidis.

The meningococcal disease is a global health threat, but is preventable through vaccination. Adjuvants improve meningococcal vaccines and are able to trigger different aspects of the immune response. The present work evaluated the immune response of mice against Neisseria meningitidis outer membrane vesicles (OMV) complexed with the adjuvants aluminium hydroxide (AH), via subcutaneous route; and dimethyldioctadecylammonium bromide (DDA) or Saponin (Sap), via intranasal/subcutaneous routes. ELISA demonstrated that all adjuvants increased IgG titers after the booster dose, remaining elevated for 18 months. Additionally, adjuvants increased the avidity of the antibodies and the bactericidal titer: OMVs alone were bactericidal until 1:4 dilution but, when adjuvanted by Alum, DDA or Sap, it increased to 1/32. DDA and Sap increased all IgG isotypes, while AH improved IgG1 and IgG2a levels. Thus, Sap led to the recognition of more proteins in Immunoblot, followed by DDA and AH. Sap and AH induced higher IL-4 and IL-17 release, respectively. The use of adjuvants improved both cellular and humoral immune response, however, each adjuvant contributed to particular parameters. This demonstrates the importance of studying different adjuvant options and their suitability to stimulate different immune mechanisms, modulating the immune response.

Lung Transplant Recipients Immunogenicity after Heterologous ChAdOx1 nCoV-19-BNT162b2 mRNA Vaccination.

(1) Background: High immunosuppressive regimen in lung transplant recipients (LTRs) hampers the immune response to vaccination. We prospectively investigated the immunogenicity of heterologous ChAdOx1 nCoV-19-BNT162b2 mRNA vaccination in an LTR cohort. (2) Methods: Forty-nine COVID-19 naïve LTRs received a two-dose regimen ChAdOx1 nCoV-19 vaccine. A subset of 32 patients received a booster dose of BNT162b2 mRNA vaccine 18 weeks after the second dose. (3) Results: Two-doses of ChAdOx1 nCoV-19 induced poor immunogenicity with 7.2% seropositivity at day 180 and low neutralizing capacities. The BNT162b2 mRNA vaccine induced significant increases in IgG titers with means of 197.8 binding antibody units per milliliter (BAU/mL) (95% CI 0–491.4) and neutralizing antibodies, with means of 76.6 AU/mL (95% CI 0–159.6). At day 238, 32.2% of LTRs seroconverted after the booster dose. Seroneutralization capacities against Delta and Omicron variants were found in only 13 and 9 LTRs, respectively. Mycophenolate mofetil and high-dose corticosteroids were associated with a weak serological response. (4) Conclusions: The immunogenicity of a two-dose ChAdOx1 nCoV-19 vaccine regimen was very poor in LTRs, but was significantly enhanced after the booster dose in one-third of LTRs. In immunocompromised individuals, the administration of a fourth dose may be considered to increase the immune response against SARS-CoV-2.

Murine typhus complicated by sHLH mimicking adult-onset Still's disease

IntroductionAdult-onset Still's disease (AOSD) is a rare multisystemic disorder and a diagnostic challenge for physicians because of the wide range of differential diagnoses. Common features of AOSD and secondary hemophagocytic lymphohistiocytosis (sHLH) could favour diagnostic uncertainty, in particular in case of infection-related sHLH. ObservationA 61-year-old man was admitted to our internal medicine department for suspected AOSD. He reported a 2-week history of sudden onset fever, headaches, myalgia, sore throat, diarrhoea, and an erythematous macular rash of the trunk as well as petechial purpuric lesions on both legs on return from Reunion Island. Laboratory tests found cytopenia, hepatic cytolysis, hypertriglyceridaemia, and hyperferritinaemia. Hemophagocytosis was diagnosed on bone marrow aspiration in favour of the diagnosis of secondary hemophagocytic lymphohistiocytosis (sHLH). Subcutaneous anakinra (100mg) was initiated to treat sHLH with favourable course. Oral doxycycline was added 3days later because of atypical features for AOSD diagnosis such as diarrhoea, hypergammaglobulinaemia, and doubtful serologies for Rickettsia and Coxiella. Three weeks later, Rickettsia typhi serology was checked again and revealed an increase in IgG titer>4 times that confirmed the diagnosis of murine typhus. A diagnosis of murine typhus complicated by sHLH was retained, successfully treated by anakinra and doxycycline. ConclusionOur observation shows that AOSD diagnosis has to be stringent due to the many differential diagnoses, particularly infection complicated by sHLH, which may be rare. It is important to consider murine typhus in patients returning from endemic areas, such as La Reunion or other tropical areas, when they present fever of unknown origin with non-specific clinical features. Moreover, this case illustrates the effectiveness of IL-1 blockers as a treatment for symptomatic sHLH without severity criteria, regardless of the aetiology.

STATE OF CYTOKINE PROFILE IN PATIENTS WITH ADENOMYOSIS

Introduction. Adenomyosis is an important problem of modern gynecology, which causes significant fertility declines, leads to disability, dysfunction of adjacent organs, decreased quality of life of women. Objective: to study the state of cytokine profile in patients with adenomyosis.Material and methods. 35 female patients of whom 20 (57.1 %) with adenomyosis of I degree (study group) and 15 (42.9%) healthy female patients (control group) were examined. We determined the content of cathelicidin (LL-37) and β-defensin IL-1β, 4, 6, 10, 18, TFN-α, VEGF in blood serum, cervical mucus and uterine lavage by immunoenzyme method. To assess cytokine imbalance, we used a ratio between IL-1β/IL-10, IL-6/IL-10, TFN-α/IL-10, IL-4/ IFN-γ. Local immunity was studied in women depending on the presence of genital pathogens. In cervical mucus, we determined the presence of HSV-1.2, CMV by the PCR method. In peripheral blood - the presence of HSV-1.2, CMV specific IgM, IgG.Results. Determination of DNA of HSV1.2, CMV pathogens by PCR analysis of cervical mucus of patients with adenomyosis showed the presence of mono-viral contamination of HSV1.2 and CMV in 40 % of cases. Moreover, HSV1.2 was detected 1.7 times more frequently than CMV (p&lt;0.05). The proportion of mixt-viral contamination (HSV1.2+CMV) was 20 %.Six (30 %) patients with adenomyosis had an increased IgG titer against HSV1,2, five (25 %) had an increased IgG titer against CMV. No IgM against HSV1.2, CMV was detected. The study of cytokine profile in blood serum of patients with adenomyosis revealed a statistically significant increase in the level of pro-and anti-inflammatory cytokines. The increase in proinflammatory cytokines was less significant, and the concentration of anti-inflammatory cytokines was more significant, especially IL-10, indicating a cytokine imbalance with Th2-type cytokines predominating. In addition, in women with adenomyosis, an increase in the concentration of pro-and anti-inflammatory cytokines was observed in cervical mucus and uterine lavage, and the dynamics correlated with the values in blood serum; the degree of increase exceeded the values in blood serum. An increase of angiogenesis factor (VEGF) both in blood serum and locally may contribute to activation of vascular growth and ectopic endometrium. On the one hand, antimicrobial peptides decrease in blood serum and to a greater extent locally (defensin in cervical mucus: 384.5±39.1 pg/ml, in uterine lavage 252.2±24.8 pg/ml; in the control group – 447.1±45.3 pg/ml, 446.2±39.3 pg/ml, respectively; ±6.8 pg/ml, in the control group – 62.2±6.1 pg/ml. In all probability, these immune changes through the mechanism of epithelial-mesenchymal transition stimulate the migration of endometrial cells to the myometrium; endocrine imbalance may also contribute to this.Conclusions. The results of the studies showed a pronounced imbalance of the cytokine profile in patients with adenomyosis in case of genital infection. Immune disorders formed against the background of viral pathogens can contribute to the penetration of the endometrium into the myometrium and the development of the disease. The subject for further research should be the search for adequate therapeutic approaches aimed at the regulation of increased proliferation and invasion of the endometrium.

Neurological Manifestations of Mycoplasma pneumoniae Infection in Hospitalized Children: A Single-Center Experience

Objective: Mycoplasma pneumoniae is one of the major causes of upper and lower respiratory tract infection in childhood. Neurological diseases are among the most common extrapulmonary manifestations.This study aimed to share our center’s experience regarding the treatment characteristics and clinical and radiological course of patients with M. pneumoniae -related neurological symptoms in light of the available evidence. Material and Methods: The study included in hospitalized patients with positive primary M. pneumoniae serology M. pneumoniae serology was examined in serum from the acute period and, if possible, convalescent serum (1-4 weeks after disease onset) using M. pneumoniae -specific immunoglobulin M (IgM) and IgG enzyme-linked immunoassay. A 4-fold or greater increase in IgG titer between acute and convalescent serum samples was considered diagnostic for M. pneumoniae infection. The clinical, laboratory, and imaging results and demographic data of patients with CNS involvement were evaluated. Results: Review of the patients’ charts showed that 13 (25%) of the 52 patients with confirmed M. pneumoniae infection had neurological symptoms and findings. When evaluated together with clinical, laboratory, and imaging results, 6 patients were diagnosed with acute cerebellar ataxia, 4 patients with encephalitis, and 1 patient each with GBS, optic neuritis, and longitudinally extensive transverse myelitis. Conclusion: Although M. pneumoniae is known as mainly a respiratory pathogen, it also causes various neurological disorders. Although all of our patients had symptoms of respiratory tract infection, it has been shown that that M. pneumoniae can also cause neurological disease without respiratory symptoms. Further studies are needed to evaluate the most appropriate methods for early diagnosis and treatment of neurological involvement, considering the long-term burden of the disease.

487 The Human Anti-Ganglioside GM1 Autoantibody Response Following Traumatic and Surgical Central Nervous System Insults

INTRODUCTION: The immune response to central nervous system (CNS) injuries has long been considered a significant contributor to secondary injury following neurotrauma however the autoimmune response to the normal immune-privileged CNS has been insufficiently considered. It has been identified as a possible pathomechanism underlying delayed dementias known to occur after TBI and SCI however the CNS-directed autoantibody response following CNS injury remains poorly understood and the autoimmune response following intra-axial brain surgery is unknown. METHODS: Nine serum samples were collected serially from 17 acute severe TBI, 22 acute SCI, and 24 intra-axial brain tumor resection patients for 30 days; 25 healthy subjects served as a control group. An ELISA assay quantitated IgG and IgM autoantibodies to ganglioside GM-1. The maximum autoantibody titers and their correlation with putative predictors such as age, gender, clinical and radiological measurements were investigated. RESULTS: Anti-GM1 IgG autoantibody titers were increased following SCI, TBI, and brain tumor resection as compared with baseline values and control patients. By contrast, anti-GM1 IgM autoantibody titers did not significantly change following insult nor show promise as a biomarker. The maximum IgG titers measured in the first 30 days were significantly increased in TBI patients (p&lt;0.01), in SCI patients (p&lt;0.01), and in brain tumor resection patients (p&lt;0.05). The highest IgG titers (or peaks) were most commonly seen at day 14 post-insult in TBI and SCI patients while brain tumor patients did not demonstrate acute increases consistent with a peak. Higher GM1 IgG autoantibodies were associated with more severe insults. The Rotterdam score strongly correlated with increased IgG titers in TBI patients (p&lt;0.05). Age and gender did not correlate with GM1 autoantibody titers in any of the types of insult we studied. CONCLUSION: These findings suggest that patients with diverse CNS insults are at risk for CNS-directed autoimmune responses and in particular those with more severe insults. These findings highlight the need to better understand the CNS-directed autoimmune response to insult, its clinical relevance and potential as a therapeutic target.

Vaccination of human participants with attenuated Necator americanus hookworm larvae and human challenge in Australia: a dose-finding study and randomised, placebo-controlled, phase 1 trial

Control of human hookworm infection would be greatly aided by the development of an effective vaccine. We aimed to develop a live attenuated human hookworm vaccine. This was a two-part clinical trial done at Q-Pharm in Brisbane (QLD, Australia) using a live ultraviolet C (UVC)-attenuated Necator americanus larvae vaccine. Part one was an open-label, dose-finding study using 50 L3 larvae suspended in water to a volume of 200 μL, attenuated with UVC exposure of 700 μJ (L3-700) or 1000 μJ (L3-1000). Part two was a randomised, double-blind, placebo-controlled, challenge study, in which participants were randomly assigned 2:1 to the vaccine group or placebo group. Healthy hookworm-naive adults aged 18-65 years with body-mass index 18-35 kg/m2 received two doses of either placebo (Tabasco sauce) or vaccine (50 L3-700) on day 1 and day 42, followed by challenge with 30 unattenuated L3 larvae to both groups. All participants received a single oral dose of 400 mg albendazole 4 weeks after each inoculation and a 3-day course (400 mg orally daily) initiated on day 161 after the challenge phase, to eliminate any remaining infection. The primary outcome of part 1 was the level of larval attenuation the resulted in a grade 2 or 3 dermal adverse event. The primary outcome of part 2 was safety and tolerability, assessed by frequency and severity of adverse events in all randomly assigned participants. Prespecified exploratory outcomes in the challenge study were faecal N americanus DNA concentration, the number of N americanus larvae recovered per g of faeces cultured, hookworm antigen-specific serum IgG antibody responses, and hookworm antigen-specific peripheral blood cytokine responses. The trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12617001007325). Between Sept 19, 2017, and Oct 24, 2018, seven participants were enrolled into three cohorts in part one (two participants in cohort 1, who received L3-700; two participants in cohort 2, who received L3-700; and three participants in cohort 3, who received L3-1000) and a further 15 were enrolled into part two. There were no serious adverse events in part one or part two. In part one, a greater number of skin penetration sites were observed after administration of L3-700 than L3-1000 (mean 15·75 [95% CI 11·18 to 20·32] with L3-700 vs 4·33 [-1·40 to 10·07] with L3-1000). Similarly, greater erythema (median 225 mm2 [IQR 150 to 325] vs 25 mm2 [12·5 to 80]) and a longer duration of the dermal reaction (median 8·0 days [IQR 3·5 to 11·5] vs 2·0 days [2·0 to 4·5]) were observed after L3-700 than L3-1000. The mean number of adverse events per participant did not differ between the groups (3·25 [95% CI 1·48 to 5·02] vs 3·00 [1·04 to 4·96]). Thus, L3-700 was used for vaccination in part two. In part two, ten participants were randomly assigned to receive L3-700 and five to placebo. Significantly more adverse events occurred after vaccination with attenuated larvae than with placebo (incident rate ratio [IRR] 2·13 [95% CI 2·09 to 5·51]; p=0·0030). There was no difference between groups in the frequency of adverse events after challenge (IRR 1·25 [0·78 to 2·01]; p=0·36). Most adverse events were mild in severity, with only one severe adverse event reported (erythematous and indurated pruritic rash >100 mm in a vaccine group participant after challenge). The eosinophil count increased in all participants after challenge, with a significantly greater increase among vaccinated participants than placebo participants (1·55 × 109 cells per L [IQR 0·92 to 1·81] in the vaccine group vs 0·49 × 109 cells per L [0·43 to 0·63] in the placebo group; p=0·014). Vaccinated participants had an IgG response to larval extract after challenge that was higher than that in placebo participants (increase in IgG titre 0·22 [IQR 0·10 to 0·41] vs 0·03 [-0·40 to 0·06]; p=0·020). Significantly fewer larvae per g of faeces were recovered in the vaccine group than in the placebo group after challenge (median larvae per g 0·8 [IQR 0·00 to 3·91] vs 10·2 [5·1 to 18·1]; p=0·014). The concentration of N americanus DNA in faeces was not significantly different between the vaccinated group and the placebo group (log10 DNA intensity 4·28 [95% CI 3·92 to 4·63] vs 4·88 [4·31 to 5·46]; p=0·14). Peripheral blood mononuclear cells from vaccinated participants exhibited significantly greater cytokine production at day 112 than placebo participants for IFNγ, TNFα, IL-2, IL-4, and IL-5 (p<0·05), but not IL-10. Vaccination with UVC-attenuated N americanus larvae is well tolerated, induces humoral and cellular responses to hookworm antigens, and reduces larval output after challenge with unattenuated larvae. Larger studies are required to confirm protective efficacy. National Health and Medical Research Council of Australia.

Malaria Infection and Risk for Endemic Burkitt Lymphoma: A Systematic Review and Meta-Analysis.

Background: Malaria infection is reportedly linked to endemic Burkitt lymphoma (eBL) in malaria-endemic areas. This study aimed to pool the overall risk (or odds) of eBL among children with previous or concurrent malaria infection. Methods: We searched PubMed, Web of Science, Scopus, and reference lists of publications for potentially relevant studies on malaria infection and eBL. The quality of the included studies was assessed using the Joanna Briggs Institute for case-control studies. Random-effects meta-analysis was used to summarize whether the odds of eBL can be increased by (1) malaria infection or (2) elevated titer of IgGs to malaria antigen. The level of heterogeneity was evaluated using Cochran’s Q statistic and I2. The individual study data, pooled odds, and confidence interval (CI) were illustrated using the forest plot. Publication bias was assessed using funnel plots and Egger’s test. Results: Ten studies were included, reporting the number of malaria cases in eBL and non-eBL (5 studied malaria infection and the odds of eBL; five studied the burden of IgGs to malarial antigens and the odds of eBL). According to the meta-analysis results, the odds of eBL was not increased by malaria infection (p = 0.562, OR: 0.87, 95% CI: 0.54–1.39, I2: 93.5%, malaria in eBL: 604/1506 cases, malaria in non-eBL: 2117/4549 cases) and the elevated titer of IgGs to malaria antigen (p = 0.051, OR: 1.50, 95% CI: 1.00–2.25, I2: 89%, increased IgG titer in eBL: 1059/1736 cases, increased IgG titer in non-eBL: 847/1722 cases). In meta-regression analysis, sex was not a confounding factor for the effect size of malaria infection and eBL (p = 0.10) and that of increased IgGs and eBL (p = 0.80). Conclusions: Malaria infection and IgG titer elevation did not increase the risk for eBL among children. However, the included studies, which are only few, do not generally agree on this point. Therefore, the risk for eBL in children diagnosed with malaria should be investigated further by longitudinal studies to confirm our evidence-based approach.