IgG Class Research Articles

Immunoglobulin Class Profiles of ABO Antibodies in Saliva and Serum of Healthy Individuals

Introduction: The coronavirus disease (COVID-19) pandemic gave rise to studies investigating the association of ABO blood group with COVID-19 susceptibility. It is hypothesized that ABO antibodies might play a role in neutralizing SARS-CoV-2. However, ABO antibodies were exclusively analyzed in blood samples. Investigation of ABO antibodies in saliva, an easy-to-obtain surrogate for respiratory secretions, may provide novel insights into mucosal immunity crucial in early defense against respiratory pathogens. Methods: In this study, saliva and serum samples from healthy individuals with known blood groups were investigated using a flow cytometric method for separate anti-A/anti-B IgA, IgM, and IgG class antibody detection. Saliva samples were additionally tested using hemagglutination-based neutral and indirect anti-human globulin test gel cards. This method comparison was complemented by dilution experiments with a high-titer anti-A/anti-B WHO standard. Results: In saliva, IgA was the most abundant ABO antibody class, followed by IgM; IgG was detected only in low levels in all non-AB blood types. In serum, IgM was the predominant ABO antibody class in all non-AB blood types, followed by IgA and IgG, the latter mainly detected in group O individuals. Saliva and serum samples of group O individuals yielded the highest variability of ABO-specific antibody levels. Regardless of sample material and blood type, major interindividual differences in ABO antibody reactivities were recorded. Antibody levels correlated moderately between these two body fluids. There were no significant sex and age-group differences in ABO antibody levels in both serum and saliva. WHO standard dilution experiments yielded technique-specific limits of detection, illustrating the inherent differences of immunofluorescence versus agglutination. Conclusion: For the first time, salivary ABO antibodies were investigated by separate detection of the three most relevant antibody classes IgA, IgM, and IgG in a healthy cohort. This study opens new perspectives regarding mucosal ABO antibody class profiles and their potential influence on respiratory infections.

Recipient-Specific Antibodies (RSA) in Mismatched Related Transplants May Induce Transplant-Associated Thrombotic Microangiopathy (TA-TMA)

HLA incompatibility increases the risk of transplant-related complications. Specifically, donor-specific antibodies (DSA) in mismatched related transplants (mm-HCT) increase the risk of graft failure. Less is known about the role of recipient-specific antibodies (RSA) detected in donors, as the immune status of the donor is not routinely examined before transplant with regard to anti-HLA antibodies. These antibodies may be transferred together with transplanted cells or produced by memory donor cells. We hypothesize that donor-derived RSA may induce immune-mediated complement activation in the classical pathway (CH50), leading to overproduction of membrane attack complex (MAC) and exacerbation of endothelial damage. Here we present preliminary epidemiological data regarding the presence of DSA and RSA, and the impact of RSA antibodies on transplant-related complications, especially transplant-associated thrombotic microangiopathy (TA-TMA) and acute graft-versus-host disease (aGvHD). Methods We prospectively analyzed the presence of anti-HLA antibodies in 20 pairs of donors and recipients qualified for mm-HCT. All recipients suffered from hematological malignancies and received a myeloablative conditioning regimen and immunosuppression consisting of post-transplant cyclophosphamide, tacrolimus, and mycophenolate mofetil. Patients’ and donors’ immunization status were tested with the solid phase method. Tests were carried out using a flow fluorometer across the screening range (Luminex Screen, One Lambda, USA). In the group of positive samples for anti-HLA class I and/or II antibodies, identification of the specificity of the HLA antibodies was performed (Luminex Single Antigen Beads, One Lambda, USA). Reagents enabling the determination of anti-HLA antibodies in the IgG class were used. All results were presented as mean fluorescence intensity (MFI) values. Monitoring of complement activation on days 30, 60, and 100 post-transplant was started after completing epidemiological data in the first 10 pairs. All patients were checked for TA-TMA and GvHD development during routine post-transplant visits. TA-TMA screening included TA-TMA triad: hypertension or kidney injury, LDH increase and decrease in number of platelets or refractoriness to transfusions, and additionally decrease in hemoglobin concentration, proteinuria, and clinical presentation with TA-TMA involved organ damage. Schistocytes as non-objective and nonrepeatable markers were excluded from diagnostic criteria. Results Anti-HLA antibodies were detected in 9/20 (45%) of recipients, and in 9/20 (45%) of the donors despite the lack of any transfusion history in donor group. Neither the presence of DSA nor RSA was affected by gender. RSAs were present more often in donors (7/9; 77%) than DSAs in recipients (2/9; 22%); p=0.052. Data summarizing MFI values and type of antibodies are presented in table 1. Laboratory diagnosis of TA-TMA met 12/20 (60%) patients, with a significant clinical presentation including severe hypertension (3) pericarditis (1), gastrointestinal (5), or neurological (6) impairment in 8/12 (66%). All patients with RSA (7/7; 100%) developed TA-TMA compared to no-RSA group (5/13; 38%) (p<0.01). TA-TMA-mediated organ damage was noticed more often in the RSA population (5/7; 71%) compared to the no-RSA group (3/13, 23%) (p<0.01); (Table 2). A trend for higher activation of CH50 and MAC in RSA compared to a no-RSA group was noted with a mean CH50 93 vs. 82 (p=0,16), and MAC 1428 vs. 1007 (p=0,24) respectively. A trend for higher maximum concentrations of tacrolimus 14 vs 10.7 (p=0.07) was observed in patients with TA-TMA. There was no impact of ABO incompatibility on TA-TMA development. During the time of observation 6 patients (30%) developed aGvHD - grades I, II, and III were diagnosed in 3, 1, and 2 patients respectively. Only 1 patient with RSA developed aGvHD. There was no correlation between RSA and GvHD occurrence (RSA 1/7, no-RSA 5/13, p=0.26) and between aGvHD and TA-TMA. CMV reactivation was documented in 13/20 (65%) patients, with no differences between the RSA and no-RSA groups (p=0.65). Conclusions RSAs occur surprisingly often in the donor population, irrespectively to the donor`s gender and the lack of transfusions history. The exact role of these antibodies is not fully understood; however, our data may suggest their impact on complement activation and TA-TMA induction. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Effects of dupilumab on hair in patients with atopic dermatitis - a review of the literature

Dupilumab is a recombinant human monoclonal antibody of the IgG4 class. Its mechanism of action can most broadly be described as inhibition of interleukin 4 and 13-mediated signal transduction. These cytokines are the main drivers of inflammatory diseases such as atopic dermatitis (AD) and asthma. Currently, dupilumab is the subject of many studies and scientific articles. More and more papers are being written about the efficacy of this drug and the side effects. Based on publications from the PubMed database, we present selected cases of atopic dermatitis patients who experienced uncharacteristic and unclear hair-related changes, such as hair loss, growth and change in hair colour, after dupilumab administration.&#x0D;

West Nile virus IgG antibodies among blood donors in Sudan: a cross-sectional study

Backgroundwhile the world is concentrated on fighting SARS-CoV-2, other viruses such as West Nile virus (WNV) attack the communities silently. West Nile Virus (WNV) is established as one of the infectious agents that transmissible blood transfusion. The present study is cross-sectional, conducted in the central blood bank, Khartoum state, Sudan, and aimed to determine WNV IgG antibodies among blood donors. Methods: the antibodies of the IgG class against West Nile virus in the serum were determined using the ELISA technique. Ninety blood donors participated in this study. Results: the results showed that 67(74.4%) of participants had positive IgG for WNV. The majority of positive participants 28/67(41.8%) had an age between 28-37 years followed by an age group 18-27 years 24/67(35.8), the dominant blood group of the positive WNV IgG participants was A+ 26/67 (38.8%) followed by O+ 19/67(28.4%). The result displayed that 40(59.7%) of the positive IgG had donated blood several times and 58 (86.6%) had a blood transfusion. Statistical analysis showed an insignificant association between age group, blood group, blood donation, blood transfusion, and West Nile Virus. Conclusions: the high IgG seroprevalence (which indicated previous infection) in the present study suggests high virus circulation in Sudan. This situation proposed that WNF screening test should be part of blood transfusion screening tests in Sudan.

RETROSPECTIVE ASSESSMENT OF THE COVID-19 INCIDENCE AND VACCINATION OF THE STAFF MEMBERS OF THE NAMS OF UKRAINE RESEARCH INSTITUTIONS

Introduction. In the conditions of the COVID-19 pandemic, there is an obvious need to achieve the appropriate level of collective immunity of personnel in medical institutions to ensure the possibility of full functioning and providing medical assistance to patients. Aim: to analyze information about the incidence of COVID-19 and SARS-CoV-2 vaccination of the staff of the Research Institutions of the National Academy of Sciences of Ukraine. Material and methods. Depersonalized information on COVID-19 disease and vaccination and levels of SARS-CoV-2 antibodies among the staff of the Research Institutions of the National Academy of Sciences of Ukraine as of November 22, 2021, statistical methods. Results. In the Research Institutions of the National Academy of Medical Sciences, the appropriate level of collective immunity was formed among the staff due to vaccinated persons and convalescents. At the pre-morbid stage, the levels of anti-SARS-CoV-2 antibodies of the IgG class were low in most of the examinees, after the disease they increased, however, in 8.5% - 10.3% of workers recovery after the disease was not accompanied by an increase in the level of anti-SARS-CoV-2 antibodies, which may carry the risk of recurrent disease. Almost a third of the examined had protective levels (&gt;4.0) of anti-SARS-CoV-2 antibodies even before the start of vaccination, having neither a documented fact nor an anamnestic data on the disease of COVID-19, which may indicate the transferred asymptomatic forms of the infection or the course of it have been under the guise of a banal acute respiratory viral disease. Adverse reactions to vaccination were mostly mild, in the form of fever, pain in the area of vaccine injection, muscle pain, rarely - dizziness, ranging from 10.2% to 33.15% depending on the type of vaccine. Conclusion. Given the continuation of the pandemic and conflicting data on the duration of immunity after vaccination or the transferred disease, it is advisable to continue monitoring the incidence of COVID 19 and assessing the levels of anti-SARS-CoV-2 antibodies in order to maintain collective immunity in each Research Institution of the National Academy of Medical Sciences of Ukraine. Key words: SARS-CoV-2, COVID-19, morbidity, vaccination

The relationship between the intensity of Gasterophilus intestinalis larvae infection and the serum and salivary humoral immune response in horses

Infection with Gasterophilus intestinalis (botfly) larvae often occurs in horses. The aim of the study was to isolate the larvae of G. intestinalis and evaluate the serum and salivary humoral immune response using self-developed ELISA in G. intestinalis infected horses. Blood serum or saliva samples were taken from 125 infected horses and 54 uninfected slaughtered horses. The antigens from G. intestinalis larvae were used for development of ELISA in order to evaluate the intensity of G. intestinalis IgG, IgM, and IgA antibody reactivity in the serum or saliva of naturally infected horses and horses without larvae in the gastrointestinal tract (control group). Serum antibodies against second and third larvae’s stadium antigens reacted significantly more intensively in infected than in healthy horses in IgG (p ≤ 0.001; p ≤ 0.05, respectively) and IgA (p ≤ 0.05;p ≤ 0.001, respectively) classes. Salivary IgG and IgA specific’s antibody reactivity was significantly higher in horses with moderate (p ≤ 0.01) and severe infection (p ≤ 0.001) compared to the healthy horses. The determination of the G. intestinalis IgG and IgA antibody activity in saliva and serum may be used for detecting horses moderately and severely infested with larvae.

Seroprevalence of Toxoplasma gondii in people at an increased risk of HIV infection – a pilot study

&lt;br&gt;&lt;b&gt;Introduction:&lt;/b&gt; The observation of the epidemiology of toxoplasmosis may prevent the development of a severe form of the disease in HIV patients.&lt;/br&gt; &lt;br&gt;&lt;b&gt;Aim:&lt;/b&gt; The aim of the study was to evaluate the seroprevalence of &lt;i&gt;Toxoplasma gondii&lt;/i&gt; in the population of the Kuyavian-Pomeranian Voivodeship at high risk of contracting HIV.&lt;/br&gt; &lt;br&gt;&lt;b&gt;Material and methods:&lt;/b&gt; Blood serum samples of 43 patients of the Consulting and Diagnostic AIDS Center were tested for the presence of anti-HIV-1/HIV-2 antibodies and p24 antigen, and for the presence of anti-toxoplasma IgM and IgG antibodies.&lt;/br&gt; &lt;br&gt;&lt;b&gt;Results:&lt;/b&gt; Anti-toxoplasma IgG antibody prevalence of 53.5% (23/43) was found in the study population, while the examination of specific IgM antibodies was negative. A high IgG antibody avidity index was obtained in 18 (94.7%) seropositive samples. Thirty (69.77%) of the samples were female, and 13 (30.23%) were male. Among men, HIV was detected in 1 (7.69%), and IgG antibodies against &lt;i&gt;T. gondii&lt;/i&gt; in 7 (53.85%) samples. IgG antibodies against &lt;i&gt;T. gondii&lt;/i&gt; were found in 16 (53.33%) women. The HIV-positive individual was 24 years old. The presence of antibodies against &lt;i&gt;T. gondii&lt;/i&gt; in the IgG class was found in people of different ages (in women aged 38.44 ±13.00 years old and in men aged 29.29 ±10.86 years old). The risky situation that could cause HIV infection is in most cases sexual contacts (79.07%).&lt;/br&gt; &lt;br&gt;&lt;b&gt;Conclusions:&lt;/b&gt; High seroprevalence of &lt;i&gt;T. gondii&lt;/i&gt; was found among the studied subjects at a high risk of HIV infection. Further research is required on a larger study group.&lt;/br&gt;

A novel platform for the production of autologous human antibodies.

At Research Genetic Cancer Centre, we have developed a novel method for the production of human monoclonal antibodies against a specific antigen of our choice (c-met) using isolated human blood cells. By mimicking nature, dendritic, CD4 and CD19 cells from healthy volunteers were driven towards Th2 immunity. Cell activation was succeeded by a cytokine cocktail, and IgG production was promoted by IgG class switching factors. IgG secretion was determined using both enzyme linked immunosorbent assay (ELISA) and Western blot as well as immunoglobulin heavy chain gamma polypeptide gene expression. Secreted antibody was further purified by affinity column chromatography against c-met peptide. Anti-c-met activity was determined using the purified antibody as primary antibody for c-met detection by ELISA, Western blot and flow cytometry. Finally, anti-c-met antibody efficiency was determined by MCF-7 viability assay. Plasma cell formation and IgG secretion took place after 6 days of culture. Plasma cells produced anti-c-met IgG antibody that significantly decreased MCF-7 breast cancer cell proliferation. To our knowledge, this is the first platform of its kind, generating fully human antibodies-on-demand using patient's own cells, bringing personalized, targeted therapy for cancer one step closer.

Anti–glomerular basement membrane disease with rapidly progressive glomerulonephritis and hemorrhagic alveolitis in pediatric patients (reviev of literature)

The article is devoted to controversial issues of autoimmune small vessel vasculitis with kidney and lung damage. Modern data on the features of pathogenesis, clinical manifestation, treatment, outcome, and prognosis of the disease with AT to GBM have presented: an idiopathic disease with AT of class IgG (IgG1 and IgG3) against non-collagen domain-1 (NC1) α3-chain ofcollagen type IV GBM (Goodpasture autoantigen); with the simultaneous increase in AT to GBM and ANCA; "de novo" diseases with AT to the α5(IV) and α3(IV) chains of GBM type IV collagen in renal graft with Alport syndrome in pediatric patients.

Development and characterization of mouse monoclonal antibodies to canine morbillivirus

Canine morbillivirus is a highly contagious multi-host pathogen with high morbidity and mortality. Timely diagnosis is of utmost importance to effectively control such a dreadful disease. Monoclonal antibodies (mAbs) serve as a high throughput diagnostics and applied tools for research and development (R&D). In the present study, a total of six mouse monoclonal antibodies were developed. All the mAbs generated belonged to IgG class. Of the six mAbs, two of them, namely CD-2F8 and CD-3D8 were directed against the nucleocapsid protein of CDV as determined in western blotting. The reactivity of all the mAbs was checked in indirect-ELISA and cell-ELISA using different morbilliviruses. The mAbs could broadly be categorized as; CDV specific (CD-3D8 and CD-2F8), cross-reactive to PPR virus (CD-AB3 and CD-4D6) and cross-reactive to both PPR virus and measles virus (CD-5D10 and CD-6E5). The characterized mAbs were used for antigenic profiling of CDV, PPR virus and measles virus. Based on the reactivity pattern; a close antigenic relationship was found among CDV and PPR virus as compared to measles virus. A pair of CDV specific mAbs namely CD-2F8 and CD-3D8 were identified which did not cross-react with measles and PPR viruses and thus could be used for diagnostic applications.

BENIGN PARTIAL ROLANDIC EPILEPSY FOLLOWING SARS-COV-2 INFECTION AND NEUROCOVID-19 EXPERIENCE: A CASE STUDY

Early evidence described by a number of scholars worldwide suggests that neuroCOVID-19 has both mild [e.g. loss of smell (anosmia), loss of taste (ageusia), neurological tics (heterophilia), visual disturbances, headaches, dizziness, disorientation] and more severe sequelae (e.g. cognitive impairment, seizures, delirium, psychosis, strokes). Long-term neurological problems or neurological deficits may also occur. The aim of this study was to describe the examination and neurotherapy of a boy following SARS-CoV-2 infection and NeuroCOVID-19 in whom neurological tics and motor automatisms as well as cognitive impairment, particularly attention deficit disorder, developed as a consequence. We present a boy K.S., 7 years old, without any neurodevelopmental disorders, following a SARS-CoV-2 infection in May 2021 and the contraction of neuroCOVID-19 confirmed by a genetic test for the quantitative detection of neutralising antibodies (responsible for immunity) in the IgG class against SARS-CoV-2. The boy had relatively mild pseudomonal symptoms of the illness: temperature 38.5, runny nose, cough, muscle aches, headaches and general weakness. He was treated symptomatically and recovered after 2 weeks. Two months later, at the beginning of July 2021, neurological tics consisting of an upward turning of the eyeballs to the left appeared. These tics intensified in August 2021 and were accompanied by motor automatisms consisting of the left hand stiffening in a salute-like position, while at the same time there was an inclination of the head to the left. In September 2021, after exertion in the swimming pool, an epileptic seizure occurred which caused the boy to start drowning. In the days that followed the above described tics and motor automatisms increased. He also developed sleep disorders, which consisted of him waking up several times during the night, during which time neurological tics and motor automatisms also appeared. Gradually, cognitive dysfunctions, especially attention deficits and behavioural changes, joined in, making it impossible for the boy to function independently at school and in many situations of daily life. Neurophysiological examination: qEEG, ERPs and sLORETA tomography performed on 11.09. 2021 using automatic seizure activity detection software showed the presence of the neuromarker benign partial rolandic epilepsy (BPERS) and neurocognitive disturbances resembling the symptoms of attention deficit hyperactivity disorder (ADHD), compared with the neuromarkers of children with this condition (n=100) from the normative database of the Human Brain Index (HBI) in Switzerland. Detection of the neuromarkerBPERS was helpful in selecting an individualised neurostimulation protocol. The patient participated in 20 neurofeedback sessions using (1) SMR reinforcement, theta inhibition; (2) theta inhibition, B1 reinforcement (15-18 Hz); (3) qEEG-guided neurofeedback. Neurostimulation with neurofeedback was conducted twice a week, for 15-20 minutes gradually increasing to 30-40 minutes per session. The patient also received individual goal-directed psychotherapy After successive sessions of neurofeedback, a gradual reduction neurological symptoms was observed. By the end of neurotherapy, neurological tics, motor automatisms, neurocognitive disorders and behavioural disturbances had completely disappeared. The patient functions well in school and achieves very good results. HBI methodology was helpful in finding functional neuromarkers of benign partial Rolandic epilepsy and disturbed cognitive control. Therefore, it was possible to offer more effective neurorehabilitation of the disorders, which contribute to a better quality of life for the patient.

Autoimmune Encephalitis: A Physician's Guide to the Clinical Spectrum Diagnosis and Management.

The rapidly expanding spectrum of autoimmune encephalitis in the last fifteen years is largely due to ongoing discovery of many neuronal autoantibodies. The diagnosis of autoimmune encephalitis can be challenging due to the wide spectrum of clinical presentations, prevalence of psychiatric features that mimic primary psychiatric illnesses, frequent absence of diagnostic abnormalities on conventional brain MR-imaging, non-specific findings on EEG testing, and the lack of identified IgG class neuronal autoantibodies in blood or CSF in a subgroup of patients. Early recognition and treatment are paramount to improve outcomes and achieve complete recovery from these debilitating, occasionally life threatening, disorders. This review is aimed to provide primary care physicians and hospitalists who, together with neurologist and psychiatrists, are often the first port of call for individuals presenting with new-onset neuropsychiatric symptoms, with up-to-date data and evidence-based approach to the diagnosis and management of individuals with neuropsychiatric disorders of suspected autoimmune origin.

Transient pseudothrombocytopenia (PTCP) in the neonate due to the mother.

Thrombocytopenia with platelet count <50×109/L is common laboratory finding in a severely ill newborn in neonatal intensive care units (ICU). Neonates with severe thrombocytopenia are at risk of bleeding. Most dangerous is intracerebral hemorrhage (ICH) frequently leading to death or lifelong neurological sequels. Pseudothrombocytopenia (PTCP) is a rare in vitro phenomenon of falsely low platelet count determined on hematology analyzers due to platelet clumping in ethylenediaminetetraacetic acid (EDTA) anticoagulated blood. PTCP was also reported in pregnant women with isolated thrombocytopenia. EDTA-PTCP in the neonate due to the transplacental transmission of maternal antibodies has been reported only in a few cases. Although PTCP is rare phenomenon, it should always be excluded in newborns with isolated thrombocytopenia to avoid erroneous interpretation of platelet and leukocyte count, unnecessary laboratory investigation of false positive antiplatelet antibodies and needless platelet transfusions. We report on two cases of transient PTCP in a neonate due to transplacental transfer of maternal EDTA-dependent autoantibodies of IgG class from the same mother.

Quo Vaditis Anti-Brain Autoantibodies: Causes, Consequences, or Epiphenomena?

Autoantibodies (ABs), often deemed pathological, have received increasing attention in the last 2 decades. Nevertheless, admittedly, we still do not know much about their physiological role nor about the circumstances that may turn them into pathologically relevant agents. Nagele et al. (1) reported early on that natural ABs of the IgG class are abundant and ubiquitous in human sera, and their number is influenced by age, gender, and disease. Even earlier, Cohen (2) postulated that human ABs of all classes are organized in clusters and that cluster analyses can potentially help differentiate healthy from disease states, demanding the development of new tools to undertake large-scale AB analyses (2).

Staphylococcus aureus peptidoglycan (PGN) induces pathogenic autoantibody production via autoreactive B cell receptor clonal selection, implications in systemic lupus erythematosus

ObjectivesThere is an intricate interplay between the microbiome and the immune response impacting development of normal immunity and autoimmunity. However, we do not fully understand how the microbiome affects production of natural-like and pathogenic autoantibodies. Peptidoglycan (PGN) is a component of the bacterial cell wall which is highly antigenic. PGNs from different bacteria can differ in their immune regulatory activities. MethodsC57BL/6 and MRL/lpr mice were intraperitoneally injected with saline or PGN from Staphylococcus aureus or Bacillus subtilis. Spleen anti-double-stranded DNA (dsDNA) IgG + B cells were sorted for B-cell receptor sequencing. Serum autoantibody levels and kidney damage were analyzed. Further, the association between plasma S. aureus translocation and systemic lupus erythematosus (SLE) pathogenesis was assessed in women. ResultsAdministration of B. subtilis PGN induced natural-like anti-dsDNA autoantibodies (e.g., IgM, short lived IgG response, and no tissue damage), whereas S. aureus PGN induced pathogenic anti-dsDNA autoantibodies (e.g., prolonged IgG production, low IgM, autoantibody-mediated kidney damage) in C57BL/6 and/or MRL/lpr mice. However, serum total IgG did not differ. S. aureus PGN induced antibodies with reduced clonality and greater hypermutation of IGHV3-74 in splenic anti-dsDNA IgG + B cells from C57BL/6 mice. Further, S. aureus PGN promoted IgG class switch recombination via toll-like receptor 2. Plasma S. aureus DNA levels were increased in women with SLE versus control women and correlated with levels of lupus-related autoantibodies and renal involvement. ConclusionsS. aureus PGN induces pathogenic autoantibody production, whereas B. subtilis PGN drives production of natural nonpathogenic autoantibodies.

Prevalence of Toxoplasma gondii among different groups of patients in Bulgaria and algorithm for diagnosis of toxoplasmosis, applied in the National Reference Laboratory for Diagnosis of Parasitic Diseases, Bulgaria

Background: Toxoplasmosis is one of the most common parasitic infections in Bulgaria. The diagnostic algorithm includes serological and molecular tests. Objectives: Aim of this study was to establish the prevalence of toxoplasmosis in examined persons and to discuss the algorithm for diagnosis of toxoplasmosis, applied in the National Reference Laboratory for Diagnosis of Parasitic Diseases, Bulgaria. Material and Methods: Data from the annual reports of the National Reference Laboratory for Diagnosis of Parasitic Diseases were used. The classes of specific IgG, IgM and IgA antibodies, and IgG avidity were identified by ELISA. Results: For the period from 2011 to 2020 a total of 2969 individuals from different regions of the country were tested for toxoplasmosis in NRL, and it was found an average seropositivity of 27%. With evidence of recent infection were 18.74% of the pregnant women, 4.5% of the patients with fever of unknown origin, 3.3% of the patients with ocular involvement and 13.9% of the tested for prophylaxis. In the group of HIV infected persons we detected only latent form of toxoplasmosis in 29.9% of the examined patients. Conclusion: For the ten-year period of the study with data on acute toxoplasmosis were 11.2% of those studied for clinical indications, and with latent infection were 27% of examined persons. We believe that the algorithm we have adopted for diagnosis is suitable for the management of the infection and helps for timely treatment in clinically manifested cases and pregnant women with data for recent infection.

Screening among Pregnant Women for Cytomegalovirus (CMV) Infection — Recommendations in Poland and Selected Countries Worldwide (a Preliminary Study to Investigate the Incidence of Neurological Complications in CMV — Infected Children)

Cytomegalovirus (CMV) is the most common cause of congenital infections worldwide, yet it remains an underestimated public health problem. There are no international standards for the prevention of vertical transmission of the infection, and the management of pregnant women as well as fetuses with symptoms of infection. The analysis was conducted between December and February 2022. The detailed criteria of inclusion in the analysis included: a separate study group, consisting only of pregnant women regardless of their stage, and statistical analysis of obtained data with particular emphasis on the result of antibodies against CMV antigens in IgG and IgM class. The introduction of universal screening is still controversial. In most countries, routine determination of IgG and IgM antibodies to CMV antigens is not recommended among pregnant women, but these tests are often offered to them independently of nationally approved screening programmes. (JNNN 2022;11(2):83–94).

ВИРУСНЕЙТРАЛИЗУЮЩИЕ МОНОКЛОНАЛЬНЫЕ АНТИТЕЛА ПРИ COVID-19: МЕХАНИЗМ ДЕЙСТВИЯ И РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЙ

The COVID-19 vaccination has become a way of effective prevention of the decease for most people globally. However, there is a cohort of patients who are not able to form a full-fledged immune response due to primary or secondary immunodeficiency conditions caused by genetic disorders, severe course of chronic diseases, due to their age or the use of drugs that suppress the immune response. The use of monoclonal viral antibodies for immunocompromised patients is the most efficient method of pre- and post-contact and even long-term prevention, as well as the treatment of coronavirus infection. Monoclonal antibodies are obtained from B-lymphocytes of patients recovered from COVID-19. As a result of further modification aimed at increasing of the efficiency and reducing the risk of unwanted phenomena in the use, the virus-neutralizing recombinant monoclonal antibodies of the IgG1 class were designed to implement preventive and therapeutic schemes for COVID-19. Treatment of a new coronavirus infection with drugs with direct etiotropic action is most effective when prescribing in the early stages of the disease, which is especially relevant in patients at risk for a severe/critical clinical course of the disease and can be performed as outpatient clinical procedures. The article analyzes the results of clinical studies of efficacy and safety of mono- and combined drugs of monoclonal antibodies to SARS-CoV-2 in patients with the new coronavirus infection, as well as potential possibilities for their use for the treatment of COVID-19 caused by the new SARS-CoV-2 strains with multiple mutations on the example of the Omicron strain.

Abstract 1390: Immunotherapy boosts B cell responses in lung adenocarcinoma

Abstract Introduction: B cells constitute a major part of the lung tumour microenvironment where they are organised in tertiary lymphoid structures (TLS) that resemble antibody-producing germinal centres. The presence of TLS has been associated with improved patient outcome and response to immunotherapy, though the mechanisms remain unclear. Similarly, the contribution of B cells and TLS to anti-tumour immunity in non-small cell lung cancer (NSCLC) remains largely unexplored. Methods: We evaluated TRACERx and TCGA NSCLC cohorts to compare B cell and TLS signatures as well as BCR sequences from human adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC). Using a novel immunogenic mouse model of LUAD, we applied lineage tracing, 3D IF, and single-cell sequencing to characterise the evolution of lung germinal centre and antibody responses over tumour progression and immunotherapy treatment. We validated immunotherapy observations in a cohort of melanoma patients with pre- and post-treatment samples. Results: We found that B cell and TLS gene set scores were significantly higher in LUAD compared to LUSC. We examined B cell signals in specific mutational backgrounds, and observed an increase in BCR CDR3 diversity and IgG class switch in the context of clonal TP53 mutation. We therefore investigated the mechanistic basis of B cells in LUAD using an immunogenic mouse model on a KRAS/TP53 background. We found that TLS organisation was triggered by CXCL13 and that exogenous CXCL13 treatment increased B cell infiltration and overall survival. Using serum transfer experiments, we demonstrated that tumour-binding class-switched antibodies played an anti-tumour role and increased survival. We found that immunotherapy increased germinal centre B cell responses and antibody quantity and quality. Using single-cell BCR sequencing of immunotherapy-treated mice, we showed clonal expansion of B cells reactive to re-expressed endogenous retroviral antigens. Furthermore, we found that KRAS G12C but not MEK inhibition boosted B cell and antibody responses. Finally, combined treatment with CXCL13 and checkpoint blockade improved survival, suggesting that boosting local B cell responses can improve immunotherapy outcome. In checkpoint blockade-treated melanoma patients, we found that BCR diversity and the number of unique antigen specificities was elevated in responders post-therapy. Non-responders showed a loss of expanded clones, suggesting that both maintenance of expanded clones and recruitment of new clones associate with successful response. Conclusions: Our work describes a novel role for B cells in the lung tumour microenvironment and establish that TLS directly contribute to anti-tumour immunity by producing class-switched protective antibodies. We demonstrate that selective boosting of anti-tumour B cells shows therapeutic potential in combination with targeted and immunotherapy. Citation Format: Katey Enfield, Kevin Ng, Jesse Boumelha, Kevin Litchfield, Oriol Pich, TRACERx Consortium, Charles Swanton, George Kassiotis, Julian Downward. Immunotherapy boosts B cell responses in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1390.

Potent neutralization by monoclonal human IgM against SARS‐CoV‐2 is impaired by class switch

To investigate the class‐dependent properties of anti‐viral IgM antibodies, we use membrane antigen capture activated cell sorting to isolate spike‐protein‐specific B cells from donors recently infected with SARS‐CoV‐2, allowing production of recombinant antibodies. We isolate 20, spike‐protein‐specific antibodies of classes IgM, IgG, and IgA, none of which shows any antigen‐independent binding to human cells. Two antibodies of class IgM mediate virus neutralization at picomolar concentrations, but this potency is lost following artificial switch to IgG. Although, as expected, the IgG versions of the antibodies appear to have lower avidity than their IgM parents, this is not sufficient to explain the loss of potency.