IgG Class Research Articles

Ocena potencjalnego wpływu wdrożenia badań serologicznych w kierunku kleszczowego zapalenia mózgu na wykrywalność tej choroby na obszarach uważanych za nieendemiczne w Polsce – doniesienie wstępne

In Poland, the number of reported cases of tick-borne encephalitis, and thus the designation of the regions of TBE occurrence, seems to be underestimated. The aim of the study was to evaluate the impact of the implementation of TBE virus infection tests in the routine diagnostics of patients with neuroinfections of undetermined viral etiology on the identification of TBE virus infections in areas considered non-endemic and finding new areas of TBE occurrence. Twenty-nine departments in which patients with suspected neuroinfections are hospitalized participated in the study. The criterion for selecting the center was the location in an area considered non-endemic for TBE, where reporting is low or absent, and intermediate data indicate the possibility of undiagnosed disease (TBE). Diagnostics were performed in the Immunoserology Laboratory at the Department of Infectious Diseases and Neuroinfections of the Medical University of Bialystok using the ELISA method. The cooperation was undertaken with infectious wards or patients with suspected neuroinfection who are hospitalized and diagnosed (e.g., neurology ward). The supervising unit is the Department of Infectious Diseases and Neuroinfections of the Medical University of Bialystok, ul. Żurawia 14, 15-540 Białystok. For testing the submitted serum and CSF samples by ELISA method were used commercial kits from Virotech (Germany). A total of 577 samples from 417 patients were tested, including 290 serum samples and 287 CSF samples. Serum antibodies against TBE were detected: IgM class in 27 samples, IgG class in 22 samples; in CSF: IgM class in 39 samples, IgG in 21 samples. The etiology of TBE was confirmed in 55 cases, i.e. in 13.19% of all tested people. 1. Detection of the presence of antibodies against TBE in samples of patients with meningitis reported as other neuroinfections indicates the etiology of TBE. 2. The number of TBE cases may be undiagnosed, and thus underestimated due to the failure to perform serological tests for TBE in areas considered non-endemic. 3. The diagnosis and reporting of neuroinfections caused by the TBE virus is essential for a proper risk assessment and in promoting prophylaxis in the form of vaccinations. 4. Preliminary results of the research indicate the need for their continuation in all voivodeships.

Immunity after HPV Vaccination in Patients after Sexual Initiation.

Vaccinations against human papillomavirus (HPV) are included in the primary prevention of precancerous intraepithelial lesions and HPV-related cancers. Despite the undeniable effectiveness of vaccination in the juvenile population, there is still little research on the effect in patients after sexual initiation. Our study aims to assess anti-HPV (L1 HPV) antibodies in healthy patients and diagnosed cervical pathology after 9-valent vaccination. We provide a prospective, ongoing 12-month, non-randomised pilot study in which 89 subjects were enrolled. We used an enzyme-linked immunosorbent assay to determine IgG class antibodies to HPV. We noted significantly higher levels of antibodies in vaccinated individuals than in the unvaccinated control group. The above work shows that vaccination against HPV might be beneficial in patients after sexual initiation as well as in those already diagnosed with HPV or SIL infection.

Research of Rickettsia spp. and Borrelia spp. in dogs in Southeast Brazil

Dogs are important in the epidemiology of tick-borne diseases, playing a significant role mainly in endemic areas of rickettsiosis and borreliosis, and serving as sentinels in epidemiological surveys. We analyzed the distribution of Rickettsia and Borrelia spp. in dogs and their ticks in the municipalities of Guaxupé, Minas Gerais, and Tapiratiba, São Paulo, Brazil, two areas non-endemic for Baggio-Yoshinari Syndrome (BYS) and rickettsiosis. Serum from 242 dogs of different ages (>12months) and breeds were tested by the Indirect Immunofluorescence Assay (IFA) using specific antigens for Rickettsia rickettsii, Rickettsia parkeri, Rickettsia amblyommatis, Rickettsia rhipicephali, and Rickettsia bellii, and by an indirect Enzyme Linked Immunosorbent Assay (ELISA) for the detection of homologous IgG antibodies against Borrelia burgdorferi American strain G39/40. Ticks were collected from the animals and subjected to PCR and nested PCR for detection of Rickettsia spp. (synthase citrate gene) and Borrelia spp. (flagellin gene). Serological data showed that 7.85% (19/242) of the analyzed dogs were seropositive for at least one of the five Rickettsia antigens tested; one (0.41%) was considered seropositive for R. parkeri (1:64) and one (0.41%) for R. rickettsii (1:256). Nine (3.72%) were considered seropositive for R. bellii and one (0.41%) for R. amblyommatis; a seroprevalence of 13.64% (33/242) for IgG class immunoreactive antibodies against B. burgdorferi was observed. A total of 148 ticks were collected from the dogs; among these 3.40% were identified as larvae of the genus Rhipicephalus and 0.70% of the genus Amblyomma; 89.8% were identified as Rhipicephalus sanguineus, 4.70% Amblyomma sculptum and 1.40% Amblyomma ovale; all negative for PCR of Rickettsia spp. and nested PCR for Borrelia spp.. The serological findings of this study suggest the circulation of Rickettsiae associated with the spotted fever group and vector ticks, just like Borrelia spp. in a non-endemic Brazilian area, drawing attention to the possibility of a zoonotic cycle in the region.

Augmenting oxidation of branched-chain amino acids (BCAAs) treats murine chronic Graft-Versus-Host Disease (cGVHD)

Abstract Aberrant immune responses, such as high Tfollicular helper (Tfh) and germinal center B cells (GCB) in cGVHD inducing antibody (Ab) secretion with tissue deposition and fibrosis, require distinct metabolic reprogramming to sustain pathogenesis. Leucine, isoleucine, and valine are essential BCAAs that signal via mTORC1 to support glycolysis and protein synthesis. Alternatively, BCAAs can be oxidized to metabolites that directly enter the tricarboxylic acid cycle or become substrates for gluconeogenesis and ketogenesis. Branched chain ketoacid dehydrogenase kinase (BDK) is a negative regulator of BCAA metabolism, decreasing downstream oxidation and increasing mTORC1 and glycolysis. We sought to determine whether increasing BCAA oxidation could be exploited to inhibit cGVHD. BDK is inhibitable by 3,6-Dichlorobenzo[β] thiophene-2-carboxylic acid (BT2), increasing BCAA oxidation and decreasing T effector (Teff) activation. In a multiorgan cGVHD model with bronchiolitis obliterans, mice that received BDK knockout vs wildtype donor T cells had improved survival and pulmonary function with decreased GCB frequencies (p-value 0.005) and a trend toward decreased Tfh/Tfollicular regulatory ratios. An in vitro assay measuring Tfh-mediated B cell Ab production showed that BT2 downregulates IgG class switching, which is key for cGVHD pathogenesis. BT2-treated T effectors but not T regulatory cells (Treg) exhibited increased oxidative phosphorylation (OXPHOS). Therefore, limiting BCAAs inhibits Teff switch from a highly glycolytic state to OXPHOS. In contrast, BCAAs are not required for Treg energy production or survival. These data suggest that augmenting BCAA oxidation could be a new therapeutic approach for treating cGVHD. Supported by NIH P01 AI056299

Вирусный гепатит как возможный триггер аутоиммунных заболеваний печени

In recent years, there has been an increase in the incidence of autoimmune liver diseases (AILD) among women and men in all age groups, their etiology remains unknown. The purpose of the study. To confirm the possible role of hepatitis viruses in the development of AILD. Material and methods. During the period 2019–2021, 141 patients with AILD were examined in the department of chronic liver Diseases of Moscow Clinical Scientific and Practical center named after A.S. Loginov of the Moscow Department of Health. The examination included the determination of anti-HAV IgG, anti-HEV IgG, HBsAg, anti-HBcorе IgG, anti-HBs, anti-HCV, DNA HBV, RNA HCV, ANA-НЕр-2, liver fibroelastometry (FE), magnetic resonance cholangiopancreatography (MRCP), liver biopsy (LB). The risk of developing AILD in people who have had hepatitis A, B, and E virus infections was assessed by calculating the odds ratio. Statistical processing was carried out by standard methods. Results. The main group consisted of patients with AILD (n = 139) of them with AIH (n = 46), PBC (n = 74), PSC (n = 19), the control group (KG) (n = 125) – without chronic liver diseases. The high prevalence of IgG class antibodies to hepatitis viruses (HV) A, B, E was reliably demonstrated among patients with AILD (n = 104; 74.8%) compared with KG (n = 68; 54.4%), P < 0.001, and anti-HCV was most often detected (n = 87; 63%), p < 0.002 and anti-HBcore (n = 36;25%), p < 0.031. The highest prevalence of anti-HAV and anti-HBcore was determined – 70% (p < 0.001) and 29% (p < 0.016), respectively, in the PBC group. No significant differences were obtained for PSC and AIH. HBV DNA was detected in the blood of two patients n = 2 (2.5%), that the presence of DNA latent viral hepatitis B. Conclusion. As a result of the study, the epidemiological relationship of transferred viral hepatitis A and B with AILD (in particular, PBС) was revealed. The data obtained confirm the role of hepatitis viruses as possible triggers of AILD and the probable involvement of HBV infection in the pathogenesis of PBC.

Diagnostics of the Epstein-Barr Virus Before and After Lung Transplantation in a Patient With Developing Posttransplant Lymphoproliferative Disease: A Case Report

The most important risk factor for the development of posttransplant lymphoproliferative disorders (PTLD) is Epstein-Barr virus (EBV) infection after transplant. It increases in seronegative EBV recipients from 23% to 50%. The aim of the study was to assess the serologic status of EBV infections (before lung transplant) and the expression of the virus itself after lung transplant in a 25-year-old patient with cystic fibrosis. In a 25-year-old patient with cystic fibrosis, immediately before lung transplant, all diagnostically significant antibodies related to EBV infection were determined in blood serum using enzyme-linked immunosorbent assay methods, using tests by Euroimmun and PerkinElmer Company. Additionally, the organ donor's serologic profile was assessed with the same tests. After lung transplant, the risk of EBV infection was monitored in whole blood and virus expression was determined by reverse transcriptase–polymerase chain reaction with Biomerieux Argene tests. Before lung transplant, the patient was shown to have no antibodies against EBV in both IgM and IgG classes. The constellation of organ donor antibodies clearly indicated a past infection. The presence of EBV virus copies in whole blood was demonstrated in the patient 9 months after transplant. Constant monitoring of the patient and modification of the treatment did not, unfortunately, protect him from the development of PTLD. The obtained results clearly confirm the purposefulness of both serologic and molecular determinations in lung recipients related to EBV. The likelihood of developing PTLD increases both in people who have not had EBV infection and patients with reactivation of the infection.

Assessment of the Serologic Status in Epstein-Barr Virus in Patients Qualified for Lung Transplantation in the First Half of 2021

The aim of the study was to assessment serologic status of Epstein-Barr virus (EBV) infections in patients qualificated for lung transplantation in the first half of 2021. The study included 72 patients qualified for lung transplantation from January to June 2021. The youngest patient was aged 14 years and the oldest was aged 65 years. The study group consisted of 36 women and 36 men. In the serum of patients, a multi-parameter, comprehensive diagnosis of EBV infections was performed using the IIFT BIOCHIP EBV sequence tests. This test is based on a combination of several substrates, enabling the simultaneous evaluation of antibodies against capsid antigens (anti-CA antibodies), both in the IgG and IgM class, early antigens (anti-EA), nuclear antigens and the assessment of the avidity of anti-CA antibodies. The analysis of all diagnostically significant antibodies specific for EBV infections, including the avidity of anti-CA antibodies, increases the diagnostic accuracy in differentiating active and past infection with EBV. In the studied group it was shown that 58 had past EBV infection (80.6%). Twelve patients (16.6%) have anti-EA antibodies, which indicate that the virus is reactivated. Only 2 patients (2.8%) had no antibodies to EBV. Comprehensive assessment of antibodies against various EBV antigens in patients qualified for lung transplantation is important in the management and further diagnosis of this infection, especially after transplantation, due to the risk of developing post-transplant lymphoproliferative disease.

The frequency of positive results of serological tests against SARS-CoV-2 in healthcare workers in Upper Silesia Metropolitan Area, Poland

Silesia is one of the regions in Poland most affected by the COVID-19 epidemic. The high number of infections among the inhabitants of the region increases the already high risk of infection of SARS-CoV-2 virus of medical workers who, due to their work, are more likely to be exposed to people with SARS-CoV-2 than people from the general population. The aim of this study is to assess the prevalence of SARS-CoV-2 infection among healthcare workers in the Upper Silesia Metropolitan Area based on the results of a seroepidemiological study. The seroepidemiological study was carried out in October- November 2020 among the inhabitants of the Upper Silesia Metropolitan Area (including medical professionals who were selected, creating a research group of healthcare workers). Apart from the questionnaire examination necessary to determine the declared symptoms, circumstances and risk factors conducive to infection, the level of specific antibodies against the SARS-CoV-2 virus in the IgG and IgM class was assessed. In the study participated 575 people declaring their medical profession. A positive test for the presence of IgG antibodies was confirmed in 19.1% of the respondents, while a positive test for IgM concerned 4.3% of the subjects. The most common positive results indicating infection with the SARS-CoV-2 virus concerned people declaring prior contact with an infected person (p = 0.001) and those undergoing quarantine (p < 0.0001). The frequency of SARS-CoV-2 virus infections in medical personnel in the Upper Silesia Metropolitan Area, assessed on the basis of a positive IgG antibody test result, was 16.1-22.5%. Med Pr. 2022;73(2):125-33.

Comparison of Bacterial Expression Systems Based on Potato Virus Y-like Particles for Vaccine Generation.

Plant-based virus-like particle (VLP) vaccines have been studied for years, demonstrating their potential as antigen-presenting platforms. In this paper, we describe the development of, and compare between, simple Escherichia coli-based antigen display platforms for the generation of potato virus Y (PVY) VLP-derived vaccines, thus allowing the production of vaccines from a single bacterial cell culture. We constructed four systems with the major cat allergen Fel d 1; namely, direct fusion with plant virus PVY coat protein (CP), mosaic PVY VLPs, and two coexpression variants of conjugates (SpyTag/SpyCatcher) allowing coexpression and conjugation directly in E. coli cells. For control experiments, we included PVY VLPs chemically coupled with Fel d 1. All constructed PVY–Fel d 1 variants were well expressed and soluble, formed PVY-like filamentous particles, and were recognized by monoclonal Fel d 1 antibodies. Our results indicate that all vaccine variants induced high titers of anti-Fel d 1 antibodies in murine models. Mice that were immunized with the chemically coupled Fel d 1 antigen exhibited the highest antibody titers and antibody–antigen interaction specificity, as detected by binding avidity and recognition of native Fel d 1. IgG1 subclass antibodies were found to be the dominant IgG class against PVY–Fel d 1. PVY CP-derived VLPs represent an efficient platform for the comparison of various antigen presentation systems to help evaluate different vaccine designs.

Could the Optiplex Borrelia assay replace the traditional, two-step method of diagnosing Lyme disease?

Serological assays for Lyme disease (LD) routinely performed in laboratories often give inconclusive results, thereby making correct diagnosis difficult and delaying treatment. The aim of the study was to assess the usefulness of a commercial Optiplex Borrelia (OB) assay in the serological diagnostics of LD. Based on the results obtained in a previous study on the seroreactivity of the sera of patients with LD to Borrelia spp. antigens using enzyme immunoassays (ELISA) and immunoblotting (IB), the same sera were re-analyzed using the OB assay. The assays carried out with the use of OB method showed a statistically significant lower number of positive/borderline results for the presence of IgM antibodies, compared to the ELISA assay. Moreover, statistically lower positive/borderline results were obtained for antibodies in the IgG class with use of the OB method, compared to the IB assay and a two-stage diagnostic protocol (ELISA with IB). The specificity analysis showed that in both the IB and OB assays, anti-OspC IgM and anti-p41 antibodies were detected. Additionally, high positive/borderline values were found in the OB assay for native antigens derived from B. afzelii lysate. The IB assay most frequently detected antibodies against OspC, p39 (BmpA) and VlsE proteins in the IgG class. There were fewer positives/borderlines for anti-p41-I B. afzelii antibodies in the OB assay and a higher number for antigens: VlsE-C6, p18 B. afzelii (DbpA), and p39 B. afzelii (BmpA). Answering the question whether the OB assay could replace the traditional, two-step method of LD diagnostics, it can be concluded that it could not. It can be used to diagnose LD only as a complementary assay and not as an optimal and dedicated method of Borrelia spp. infection detection.

COVID-19 Vaccines in Pancreatic Transplant Recipients: A Single-Center Observative Study

The SARS-CoV-2 pandemic was a real test of doctors’ abilities to adapt and respond to patients’ needs. The course of infection varied from influenza-like symptoms to severe infections with multi-organ failure and death. Therefore, the possibility of vaccination against the COVID-19 virus brought great hope.Since 2004, 240 pancreas and pancreas with kidney (simultaneous pancreas and kidney transplantation, pancreas after kidney, pancreas transplants alone) transplants were performed in our center. Currently, 130 transplant patients are under the care of the transplant clinic. All patients were informed about the possibility of vaccination against SARS-CoV-2 with the mRNA vaccine.The aim of the study was to evaluate the development of antibodies to SARS-CoV-2 in patients who had previously undergone transplantation. Fifty-three patients were vaccinated with the full double dose and 37 patients received an additional third dose.The level of antibodies in the IgM and IgG classes was assessed in patients’ serum. The level of antibodies was assessed before administration of the vaccine and then after administration of the first and second doses.Most patients had no response to vaccination after 1 dose of the vaccine and 21 patients achieved therapeutic antibody levels after the full dose of vaccination. However, the highest titer of immunoglobulins was found in recipients who received the third dose.The use of vaccinations is safe and can protect the group of patients after pancreas transplantation from serious complications of SARS-CoV-2 infection despite the use of immunosuppressive drugs.

Analysis of predictors of response to anti-IgE therapy in patients with severe atopic bronchial asthma in real clinical practice

Guidelines on Biological Therapy for Bronchial Asthma of the European Academy of Allergy and Clinical Immunology (EAACI) identified a number of controversial issues for additional outcome analysis using randomized clinical trials and data from routine clinical practice. In particular, there is unmet need to clarify algorithms for prescribing biologicals using predictors of response and its timing, taking into account risk factors and multimorbidity. Omalizumab is a recombinant humanized monoclonal anti-IgE antibody of IgG1 class used for the treatment of severe refractory atopic bronchial asthma (BA) and a variety of IgE-mediated diseases. Among biological agents, this "pioneer molecule" has the greatest experience in the "allergology and immunology" profile. Detailed description of the "nonresponders" portraits will allow to perform the therapy response assessment on time and facilitate rational planning of individual therapy, which is a prerequisite for biologicals era. Using only routine methods, it is possible to perform initial and dynamic screening to phenotype a heterogeneous cohort of patients with severe asthma and chose the optimal strategy. To identify predictors of nonresponse to omalizumab anti-IgE therapy in patients with severe atopic BA and to establish optimal timing of efficacy assessment using retrospective analysis of data from the Biologic Therapy Registry of Allergology and Immunology in routine clinical practice. A retrospective single-center registry study was conducted at the Allergy and Immunology Reference Center from June 2017 to August 2021. 135 patients with severe BA, with confirmed perennial sensitization, who received omalizumab according to the recommendations of the current version of GINA, were selected from the clinical and dynamic observational system (registry). Dosing regimen and administration frequency of omalizumab were determined in accordance with the instructions for the drug. Assessment of therapy efficacy was performed at the time point 4, 6 and 12 months. Patients were subgrouped into "responders" and "non-responders" according to the following criteria: ACT score less than 19 and/or difference between initial ACT score in dynamics less than 3 points; forced expiratory volume in the first second less than 80%; combination of these two criteria. Nonparametric methods of descriptive statistics were used in data processing: median, interquartile range. Differences were considered significant at p0.05. MannWhitney U-test, KruskalWallis one-way analysis of variance, and Fisher's 2 test were used to compare quantitative characteristics. Heterogeneous subgroups of patients differing in reaching the criteria of "non-responders" to treatment were identified; the informativity of modifiable and unmodifiable factors differed at time-points of dynamic observation. In the differential analysis, two profiles of "nonresponders" were defined in combination with the most significant predictors of "nonrsponse" to omalizumab. According to the data obtained, one of the clinical phenotypes, namely the combination of severe asthma with the Samters triad, corresponded to the characteristics of the patient "nonresponders": age of onset is about 30 years, females, severe exacerbations of BA while taking non-steroidal anti-inflammatory drugs, accompanied with high levels of eosinophilia. The data obtained illustrates the hypothesis of pathogenetic heterogeneity of severe BA with the phenomenon of overlapping phenotypes and can serve as an additional orienteer for creating the individual plan of anti-IgE therapy in real clinical practice.

Specificity of mouse and human Fcgamma receptors and their polymorphic variants for IgG subclasses of different species.

IgG is the predominant antibody class generated during infections and used for the generation of therapeutic antibodies. Antibodies are mainly characterized in or generated from animal models that support particular infections, respond to particular antigens or allow the generation of hybridomas. Due to the availability of numerous transgenic mouse models and the ease of performing bioassays with human blood cells in vitro, most antibodies from species other than mice and humans are tested in vitro using human cells and/or in vivo using mice. In this process, it is expected, but not yet systematically documented, that IgG from these species interact with human or mouse IgG receptors (FcγRs). In this study, we undertook a systematic assessment of binding specificities of IgG from various species to the families of mouse and human FcγRs including their polymorphic variants. Our results document the specific binding patterns for each of these IgG (sub)classes, reveal possible caveats of antibody-based immunoassays, and will be a useful reference for the transition from one animal model to preclinical mouse models or human cell-based bioassays.

Cross-Reactive Results in Serological Tests for Borreliosis in Patients with Active Viral Infections.

Currently, serological tests for Lyme disease (LD), routinely performed in laboratories following the European Concerted Action on Lyme Borreliosis recommendations as part of two-stage diagnostics, are often difficult to interpret. This concerns both the generation of false positive and negative results, which frequently delay the correct diagnosis and implementation of appropriate treatment. The above problems result from both morphological and antigenic variability characteristics for the life strategy of the spirochete Borrelia burgdorferi sensu lato, a complicated immune response, and imperfections in diagnostic methods. The study aimed to check the reactivity of sera from 69 patients with confirmed infection with Epstein–Barr virus (EBV), cytomegalovirus (CMV) and BK virus (BKV) with Borrelia antigens used in serological tests: indirect immunofluorescence (IIFT), enzyme-linked immunosorbent (ELISA) and immunoblot (IB). In the group of patients infected with EBV, the highest percentage of positive/borderline anti-Borrelia IgM and IgG results was obtained in the following tests: IIFT (51.9% for IgM, 63.0% for IgG), ELISA (22.2% for IgM, 29.6% for IgG) and IB (11.1% for IgM, 7.4% for IgG). In the group of CMV-infected patients, the highest percentage of positive/borderline anti-Borrelia IgM results were obtained in the following tests: IB (23.1%), IIFT (15.4%) and ELISA (7.7%), while in the IgG class in the IIFT (15.4%), IB (11.5%) and ELISA (3.9%) tests. In the group of patients infected with BKV, the highest percentage of positive/borderline anti-Borrelia IgM results was obtained in the following tests: IIFT (25.0%), IB (25.0%) and ELISA (3.9%), and in the IgG class in the tests: IB (50.0%), IIFT (6.2%) and ELISA (6.2%). The native flagellin (p41) and OspC proteins were the most frequently detected Borrelia antigens in all studied groups of patients in both classes of antibodies. Similar to other authors, the study confirmed the fact that serological tests used in the diagnosis of LD have a high potential to generate false positive results in patients with active viral infections, which may be related to cross-reacting antibodies appearing during the most common polyclonal activation of T/B lymphocytes, activated by viral superantigens.

Effects of storage and processing conditions on IgG1 monoclonal antibodies

Unfolding and aggregation of monoclonal antibodies (mAbs) can cause pathologic immunogenicity and significant loss of material during production and processing. Destabilizing conditions were used to accelerate degradation and probe environment effects relevant to pharmaceutical formulations. Currently approved mAb therapeutics harness the immunological capability of the major IgG class of immunoglobulin in blood serum; the IgG1 subclass was selected for our studies. High hydrostatic pressure (HP) was used for in-situ measurements of subzero °C temperatures in the absence of ice.

Seroprevalence and Risk Factors of Trichinella spiralis Infection in Blood Donors from Western Romania.

Background and Objectives: Trichinellosis, a serious and sometimes fatal human disease, is a foodborne zoonotic disease with worldwide distribution caused by parasitic nematodes of the genus Trichinella. Humans are infected with Trichinella larvae through the ingestion of meat that has not been properly cooked. Romania reported most of the confirmed cases of trichinellosis among the EU countries. The aim of this cross-sectional study was to evaluate, for the first time, the seroprevalence and risk factors of Trichinella infection in blood donors from Western Romania. Materials and Methods: Serum samples of 1347 consecutive blood donors were investigated using an immunoenzymaticassay (ELISA) for the determination of specific IgG class antibodies against T.spiralis. A questionnaire interview was used to obtain information regarding the potential risk factors associated with T. spiralis infection. Mantel–Haenszel chi-squared test or the Fisher exact two-tailed test, as appropriate, were used for comparison between T. spiralis positive and T. spiralis negative blood donors. Student’s t-test was used to evaluate differences between means in studied groups and body mass index was calculated by dividing weight in kilograms by height in meters squared. Statistical analysis was performed using Epi Info Version 7.2 and Stata 16.1. Results: T. spiralis IgG antibodies were detected in 2.00% (27) of 1347 consecutive blood donors. Eating raw and/or undercooked meat, from pigs or wild boars, was found to be the main risk factor (p < 0.001). Strong alcoholic drink consumption was highly associated with T. spiralis infection (p = 0.009). Trichinella seroprevalence was higher among rural residents and males. Subjects identified as Trichinella seropositive were not previously diagnosed and have not been treated for Trichinella infection with any specific therapy. Conclusions: The demonstration of T. spiralis antibodies in healthy blood donors suggests that Trichinella infection may be detected in asymptomatic individuals that were not previously diagnosed with this zoonosis.

Autoantibodies against SUMO1-DHX35 in long-COVID

Long COVID is a collection of symptoms as a late sequelae of SARS-CoV-2 infection. It often includes mental symptoms such as cognitive symptoms, persisting loss of smell and taste, in addition to exertional dyspnea. A role of various autoantibodies (autoAbs) has been postulated in long-COVID and is being further investigated. With the goal of identifying potentially unknown autoAbs, we screened plasma of patients with long COVID on in-house post-translationally modified protein macroarrays including citrullinated, SUMOylated and acetylated membranes. SUMO1ylated isoform DEAD/H (Asp-Glu-Ala-Asp/His) box helicase 35 (SUMO1-DHX35) was identified as only candidate antigen. In adult patients with long COVID, IgG autoAbs against SUMO1-DHX35 of IgG class were found in seven of 71 (9.8%) plasma samples, of IgM and IgG class in one of 69 (1.4%) samples, not in 200 healthy adult controls, not in 442 healthy children, and 146 children after SARS-CoV-2 infection. All autoAb-positive seven patients were female. AutoAb titers ranged between 200 to up to 400 By point mutagenesis and expression of FLAG-tagged mutants of DHX35 in HEK293 cells, and subsequent SUMOylation of purified constructs, lysine 53 was identified as a unique, never yet identified, SUMOylation site. The autoAbs had no reactivity against the non-SUMO1ylated mutant (K53R) of DHX35. To summarize, autoAbs against SUMO1-DHX35 were identified in adult female patients with long-COVID. Further studies are needed to verify the frequency of occurrence. The function of DHX35 has not yet been determined and there is no available information in relation to disease implication. The molecular mechanism causing the SUMOylation, the potential functional consequences of this post-translational modification on DHX35, and a potential pathogenicity of the autoAbs against SUMO1-DHX35 in COVID-19 and other possible contexts remain to be elucidated.

A Case Series of Recalcitrant Pemphigus

Pemphigus consists of a group of life threatening autoimmune bullous disorders characterised by flaccid blisters and erosions of the skin and mucosal membranes of oral, laryngeal, conjunctival, pharyngeal, anal, vaginal etc. Pemphigus vulgaris involves mucosa in 50- 70% of the patients. Pemphigus is associated with other autoimmune disorders like myasthenia gravis and thymoma. Primary subsets of pemphigus include pemphigus vulgaris, pemphigus foliaceus and paraneoplastic pemphigus. Pemphigus vulgaris constitutes nearly 70% of cases of pemphigus, with its antigens desmoglein 1 and 3, which are calcium dependent calmodulins, being the crucial targets for IgG1 and IgG4 classes of antibodies. If left untreated at an early stage, pemphigus vulgaris is associated with significant morbidity and mortality. The authors present a case series of recalcitrant pemphigus with focus on the various factors that affect the disease outcomes, morbidity and mortality

Determination of Low IgG Class Antibody Avidity Percentage by IgM Levels Specific to Toxoplasma Gondii.

Ig (Immunglobulin) M detection and low avidity index are markers of recent infection in differentiating acute and chronic stages of Toxoplasma gondii (T. gondii) infections. In this study, we aimed to evaluate whether the anti-T. gondii IgM antibody index threshold value could be a predictive factor in the estimation of low avidity and its use in improving the diagnosis of early toxoplasma infection. Anti-T. gondii IgM, IgG antibody and IgG avidity results were analyzed. Anti-T. gondii IgG and IgM antibodies in blood samples were studied with chemiluminescent microparticle immunoassay (CMIA), and IgG avidity test was performed with Enzyme Linked Fluorescent Assay (ELFA) technique. The overall seroprevalence of anti-T. gondii antibodies (IgG and/or IgM) was 19.4%. Of the 64 patients whose avidity tests were studied, 47 (73.4%) were female. Twenty seven (57.4%) of the women were pregnant. In the IgG avidity test, 7.8% low avidity was detected. Low avidity was detected in only 4 (15.4%) of 26 IgM positive cases. IgM analysis of a case (6-month-old baby) with low avidity was found to be negative. In the prediction of low avidity, the assay's IgM positivity cutoff value was ≥ 0.6, its sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 62.7%, 2.3%, and 99.7%, respectively. With Architect, 37.3% of samples were false positive. Determining the IgM index cutoff value was unsuccessful in distinguishing low avidity. The area under the ROC curve was 0.574 (p = 0.60). In our study, the positive predictive value of the IgM test kit in estimating low avidity was low and the false positivity rate was 37.3%. It is thought that the index cutoff value of the anti-T. gondii IgM antibody test kit cannot be considered as a good predictor of recent infection. Studies with larger patient groups are needed.

Antibodies Against Unusual Forms of Sialylated Glycans.

Previous studies have shown that in the blood of healthy donors (1) there are no natural antibodies against sialylated glycoproteins, which contain Neu5Acα (N-acetylneuraminic acid) as the most widespread form of human sialic acid, and (2) there is a moderate level of antibodies capable of binding unnatural oligosaccharides, where Neu5Ac is beta-linked to a typical mammalian glycan core. In the present study, we investigated antibodies against βNeu5Ac in more detail and verified the presence of Kdn (2-keto-3-deoxy- D-glycero-D-galacto-nonulosonic acid) as a possible cause behind their appearance in humans, taking into account the expected cross-reactivity to Kdn glycans, which are found in bacterial glycoconjugates in both the α- and β-forms. We observed the binding of peripheral blood immunoglobulins to sialyllactosamines (where “sialyl” is Kdn or neuraminic acid) in only a very limited number of donors, while the binding to monosaccharide Kdn occurred in all samples, regardless of the configuration of the glycosidic bond of the Kdn moiety. In some individuals, the binding level of some of the immunoglobulins was high. This means that bacterial Kdn glycoconjugates are very unlikely to induce antibodies to βNeu5Ac glycans in humans. To determine the reason for the presence of these antibodies, we focused on noninfectious pathologies, as well as on a normal state in which a significant change in the immune system occurs: namely, pregnancy. As a result, we found that 2/3 of pregnant women have IgM in the blood against Neu5Acβ2-3Galβ1-4GlcNAcβ. Moreover, IgG class antibodies against Neu5Acβ2-3Galβ1-4GlcNAcβ and Neu5Acβ2-6Galβ1-4GlcNAcβ were also detected in eluates from the placenta. Presumably, these antibodies block fetal antigens.