Specific IgG Antibodies Research Articles

Serological evidence of possible Borrelia afzelii lyme disease in Greece

Suggestions that Lyme disease exists in Greece remain controversial and no study to date has definitively identified the presence of a Borrelia species that infects humans. We examined patients throughout Greece suspected for Lyme disease by enzyme-linked immunosorbent assay (ELISA) and by western blotting for Borrelia burgdorferi sensu lato species. We found one patient positive for Borrelia burgdorferi and two patients positive for Borrelia afzelii specific IgG antibodies. Both B. afzelii patients were suffering by neurological manifestations and had never traveled abroad. We provide serological evidence of two autochthonous Lyme disease cases in Greece, possibly caused by B. afzelii.

Immunoregulatory effects of Lactococcus lactis-derived extracellular vesicles in allergic asthma.

BackgroundProbiotics have been shown to prevent various allergic diseases by producing extracellular vesicles (EVs). However, the role of EVs in allergic asthma has not yet been completely determined.MethodsGut microbial composition, mainly genera related to probiotics, was investigated in allergic asthmatic mice. Moreover, EVs were isolated from Lactococcus lactis (L. lactis, a selected bacterium) and EV proteins were identified by peptide mass fingerprinting. EV functions in immune responses were evaluated in vivo or ex vivo. Furthermore, the levels of specific IgG antibodies (an alternative marker for EV quantification) to L. lactis‐EVs were measured by ELISA in the sera of 27 asthmatic patients and 26 healthy controls.ResultsAllergic asthmatic mice showed a lower proportion of Lactococcus compared to healthy mice. L. lactis was cultured and its EVs abundantly contained pyruvate kinase. When allergic asthmatic mice were intranasally treated with EVs, airway hyperresponsiveness, eosinophil number, cytokine secretion, and mucus production were significantly decreased. Moreover, L. lactis‐EV treatment shifted immune responses from Th2 to Th1 by stimulating dendritic cells to produce IL‐12. In addition, significantly lower levels of serum specific IgG4 (but not IgG1) to L. lactis‐EVs were noted in asthmatic patients than in healthy controls. A positive correlation between the levels of EV‐specific IgG4 and FEV1 (%), but a negative correlation between the levels of EV‐specific IgG4 and IL‐13 were observed.ConclusionThese findings suggest that L. lactis‐EVs may have immune‐regulating effects on airway inflammation mediated by dendritic cell activation, providing a potential benefit for allergic asthma.

Therapeutic effects of dracocephalum heterophyllum in collagen-induced arthritis

Rheumatoid arthritis (RA) is an autoimmune and inflammatory disease characterized by synovial inflammation, joint swelling, and cartilage and bone destruction. Dracocephalum heterophyllum (DH) is a compound in traditional Chinese herbal medicine well known for its anti-inflammatory, antiviral and antioxidant activities. In the present work, the therapeutic effects of DH were investigated in collagen-induced arthritis. Arthritis severity was assessed by clinical score, X-ray, and histopathological features. Expression of inflammatory cytokines was detected by qPCR and ELISA whereas anti-type II collagen antibodies were determined by ELISA. DH treatment significantly alleviated clinical scores, synovial inflammation, joint swelling, and cartilage and bone destruction. DH also reduced the production of inflammatory cytokines, including tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and interleukin-1β (IL-1β), and decreased the serum levels of anti-type II collagen specific IgG antibodies in collagen-induced arthritis. The therapeutic effects of DH in collagen-induced arthritis provide evidence that DH might be a potential therapeutic drug for rheumatoid arthritis.

Potential mechanisms involved on how systemic IgG antibodies specific to vascular endothelial growth factor (VEGF) and induced by active immunotherapy decrease platelet derived free-VEGF

CIGB-247 is a vascular endothelial growth factor (VEGF)-based active immunotherapy and it is currently under investigation for cancer treatment. This specific active immunotherapy encompasses two vaccine candidates that use a human VEGF variant molecule as antigen, in combination with two clinically tested adjuvants: VSSP or aluminum phosphate. CIGB-247 has been evaluated in patients with advanced solid tumors, recruited in two phase I clinical trials, and it has been shown to be safe and immunogenic by activating both cellular and humoral immune responses against human VEGF. The immunization induces specific IgG antibodies, and also shows as effect, the reduction of free-VEGF levels within platelets (platelet-derived free VEGF). The production of systemic IgG antibodies and the presence of VEGF in another compartment, almost exclusively within platelets, have arisen some questions about this effect detected in the vaccinated-cancer patients. Based on some relevant published works about platelet endocytosis and VEGF pharmacodynamics during bevacizumab treatment as well as the phase I clinical data of CIGB-247, this investigation aims to hypothesize and analyze the potential mechanisms involved in the reduction of platelet-derived free VEGF as a result of vaccination with CIGB-247. Abbreviations: FcγR: Fc gamma receptors; IC: immune complexes; VEGF: vascular endothelial growth factor; VEGFR1: vascular endothelial growth factor receptor 1; VEGFR2: vascular endothelial growth factor receptor 2.

Blunted Post-COVID-19 Humoral Immunity in Patients With CNS Demyelinating Disorders on Anti-CD20 Treatments.

With unclear characteristics of post-infection and post-vaccination immunity, the multiple sclerosis community lacks evidence to guide patients on their continued coronavirus disease 2019 (COVID-19) infection risk. As disease modifying treatments all modulate the immune system, we expect their use to alter acquired immunity to COVID-19, but the specific impact of individual treatments is unclear. To address this, we analyzed the patient and COVID-19 specific characteristics associated with post-infection humoral immunity in 58 patients with central nervous system (CNS) demyelinating disorders in the Boston metropolitan area. Univariate analysis of variance was performed using Mann Whitney U test for continuous variables, and Chi Square or Fisher Exact test for nominal variables. Univariate and stepwise multivariate nominal logistic regression identified clinical characteristics associated with COVID-19 specific nucleocapsid IgG antibody formation post-infection. Our cohort demonstrated a 42% post-infection seropositive rate with a significantly higher rate observed with shorter duration between infection and antibody collection and use of natalizumab over no/other treatment. Use of anti-CD20 treatments compared to no/other treatment was associated with a significantly lower rate of seropositivity. However, only shorter duration between infection and antibody collection as well as use of no/other treatment compared to anti-CD20 treatment were found to be independently associated with increased likelihood of post-infection seropositivity. Additionally, we demonstrate durability of antibody response up to 9 months in a small subset of patients. Thus, our data supports that patients with CNS demyelinating disorders regardless of DMT are able to form a measurable antibody response after COVID-19 infection, and that patients on anti-CD20 treatments form less robust immunity after COVID-19 infection.

Epidemiology of Toxoplasmosis in SERBIA: A Cross-Sectional Study on Blood Donors.

Toxoplasmosis is a globally distributed parasitic zoonosis, affecting approximately one third of the human population. Epidemiological studies on toxoplasmosis conducted in Serbia so far have been focused on women of childbearing age, without a clear insight into the prevalence in the general population. We conducted a cross-sectional study in a representative sample of the healthy adult population consisting of 1095 blood donors of both genders to establish the prevalence and risk factors for Toxoplasma gondii infection. Data on the demographic and clinical characteristics of all study participants, as well as on their lifestyle habits, were collected by means of a questionnaire. The overall prevalence of infection was 20.5% (224/1095) and the avidity of the specific IgG antibodies detected was high in a vast majority of the seropositive donors (98.2%). Interestingly, the remaining 1.8% of the specific IgG positive samples were of borderline avidity (4/224), in complete absence of specific IgM. The multivariate logistic regression analysis showed that independent risk factors included age (from OR (95% CI) 1.9 (1.13–3.28) in the 30–39 age group, to 6.8 (3.27–14.24) in the age group of >60 years), suburban living (OR (95% CI) 2.2 (1.43–3.34)) and contact with soil (OR (95% CI) 1.4 (1.01–1.94)). This first large-scale study on toxoplasmosis in the general population in Serbia shows the lowest prevalence ever reported in this country. Moreover, the novel perspective on risk factors provides an updated basis for future prevention programs.

Abstract P3-11-02: Evaluation of the effects of anticancer treatments in cancer patients undergoing SARS-COV2 vaccination (VAX-on study: Breast cancer subgroup analysis)

Abstract Background: Since the beginning of the covid19 pandemic, clinical and demographic data showed that cancer patients are at high risk of developing severe consequences of Sars-Cov2 disease. For this reason, vaccination is strongly recommended, especially for patients on active treatment. Nevertheless, the efficacy of the Sars-Cov2 vaccine in cancer patients is not fully investigated. Our trial aim to explore the seroconversion in a large series of vaccinated cancer patients undergoing active treatment. Here we present a subgroup analysis concerning patients affected by breast cancer. Methods: The “VAX-on” is a single-center study that enrolled 366 cancer patients who underwent oncological treatment within the last six months. The study was approved by the ethics committee and all patients had to sign specific informed consent to be enrolled. Subjects were vaccinated against Sars-Cov2 with mRNA vaccine BNT162b2 (Comirnaty) - Pfizer BioNTech. Blood samples were obtained to quantify the production of specific anti-Spike IgG antibodies at day 21 from the first dose and at 6-8 weeks after the second dose. The antibody laboratory title cut-off of 50 U.A./mL defined the seroconversion. Results are shown as Mean and Standard Deviation for continuous variable, percentage (%) for categorical ones. The Mann-Whitney test or Chi-Square test were used to compare continuous or categorical groups, respectively. Results: A total of 100 patients with breast cancer were enrolled. Clinical and demographic data are summarized in Table 1. The median age was 60.5 years and the majority had an ECOG PS of 0 (75%). Almost all were women (97%), with advanced cancer in 60% of cases. In early or advanced setting 46% patients were treated with chemotherapy while 54% were on target therapy (also including monoclonal antibody and CDK4/6 inhibitors). The mean antibody title after the first dose of mRNA Comirnaty vaccine was 2185.03±9303.26 U.A./mL (M±SD), while after the second dose the mean antibody title rise to 6492.10±10425.95 (M±SD). After the first dose 61% of patients were considered as immunized, meanwhile after the second dose 86% of patients resulted immunized (defined as an antibody title >50 U.A./mL). In the 9 patients in treatment with steroids (prednisone > 10mg/die or equivalent), there was a trend to a decreased antibody development compared to patients without chronic use of steroids (p 0.06 and 0.05 after the first and second dose, respectively). Of interest, patients using G-CSF (12%) had a significant reduction in the production of Sars-Cov2 antibody after vaccination compared to patients who did not use them (p 0.02 and <0.001 after the first and second dose, respectively), with only 75% resulted positively immunized after the second dose (p=0.04). No differences were seen when comparing patients in advanced with non-advanced stage. Conclusions: Our study demonstrated 86% seroconversion in cancer patients after the second dose of mRNA vaccine regardless of disease stage or type of cancer treatment received. Further evaluations are needed to define whether the use of corticosteroids and G-CSF have an impact on seroconversion. Table 1.Parameters *Gender (F) (%)97 (97.00)Age (yrs)60.55±11.94Advanced Stage (Yes) (%)60 (60.00)ECOGPS (%)075 (75.00)121 (21.00)24 (4.00)Setting (%)Other Therapy60 (60.00)Adjuvant & Neoadjuvant40 (40.00)Therapy (%)Other46 (46.00)Target54 (54.00)Last cycle <28 days (Yes) (%)81 (81.00)Timing CHT 1st Dose17.75±28.66Timing CHT 2nd Dose15.80±28.44Steroids (>10 mg)/> 7 days9 (9.00)FANS last 7 days (Yes) (%)15 (15.00)G-CSF last 21 days (Yes) (%)12 (12.00)Previous Allergies (Yes) (%)19 (19.00)Antibody Title 1st Dose2185.03±9303.26Antibody Level 1st Dose (>50) (%)61 (62.89)Antibody Title 2nd Dose6492.10±10425.95Antibody Level 2nd Dose (>50) (%)86 (92.47) Citation Format: Agnese Fabbri, Eleonora Marrucci, Fabrizio Nelli, Marco Mazzotta, Angelo Onorato, Primi Francesca, Mario Giovanni Chilelli, Antonella Virtuoso, Carlo Signorelli, Julio R Giron Berrios, Marta Schirripa, Rossella Donghia, Enzo Maria Ruggeri. Evaluation of the effects of anticancer treatments in cancer patients undergoing SARS-COV2 vaccination (VAX-on study: Breast cancer subgroup analysis) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-11-02.

Toxoplasma Gondii Enhances Oxidative Stress in Pregnant Women: A Case-Control Study

Toxoplasma gondii (T. gondii) is an intracellular protozoan parasite that causes the disease Toxoplasmosis. Acute infection of T. gondii in pregnant women is dangerous because the parasite can transmit into developing foetus and can cause congenital toxoplasmosis. To assess the prevalence of T. gondii infection, its association with pregnancy and the impact of this parasite on generating oxidative stress, ninety-two pregnant women and sixty-five age matched non-pregnant control subjects were enrolled in this study. Using an immunological assay with a rapid test cassette, T. gondii specific IgG antibody was detected in 25% pregnant women while it was found only 9.2% in non-pregnant healthy control subjects, suggesting that a higher percentage of pregnant women carried chronic T. gondii infection compared to control subjects. Anti-T. gondii IgM was also tested and found to be positive in only 3.3 % pregnant women as compared to control. Polymerase Chain Reaction analysis was carried out with the DNA isolated from blood of both anti-T. gondii IgM and IgG positive pregnant women and was found to be negative for T. gondii REP-529 gene, suggesting a chronic infection. Our data suggest that pregnant women who were in contact with cat in their third trimester of pregnancy demonstrated a significantly higher association with acquiring infection. Furthermore, to determine any association of T. gondii infection with oxidative stress in pregnant women, oxidative stress markers were assessed in plasma samples. The total oxidative stress was found to be higher in T. gondii positive subjects compared to T. gondii negative samples whereas total antioxidant defence was observed to be slightly decreased in T. gondii positive pregnant women. It can primarily be said that chronic T. gondii infection in pregnant women may increase oxidative stress and this, therefore, may act as a risk factor for congenital toxoplasmosis. Dhaka Univ. J. Biol. Sci. 31(1): 79-91, 2022 (January)

Protective Immunity against Listeria monocytogenes in Rats, Provided by HCl- and NaOH-Induced Listeria monocytogenes Bacterial Ghosts (LMGs) as Vaccine Candidates.

Listeria monocytogenes (Lm) bacterial ghosts (LMGs) were produced by the minimum inhibitory concentration (MIC) of HCl, H2SO4, and NaOH. Acid and alkali effects on the LMGs were compared by in vitro and in vivo analyses. Scanning electron microscope showed that all chemicals form lysis pores on the Lm cell envelopes. Real-time qPCR revealed a complete absence of genomic DNA in HCl- and H2SO4-induced LMGs but not in NaOH-induced LMGs. HCl-, H2SO4- and NaOH-induced LMGs showed weaker or missing protein bands on SDS-PAGE gel when compared to wild-type Lm. Murine macrophages exposed to the HCl-induced LMGs showed higher cell viability than those exposed to NaOH-induced LMGs or wild-type Lm. The maximum level of cytokine expression (TNF-α, iNOS, IFN-γ, and IL-10 mRNA) was observed in the macrophages exposed to NaOH-induced LMGs, while that of IL-1β mRNA was observed in the macrophages exposed to HCl-induced LMGs. To investigate LMGs as a vaccine candidate, mice were divided into PBS buffer-injected, HCl- and NaOH-induced LMGs immunized groups. Mice vaccinated with HCl- and NOH-induced LMGs, respectively, significantly increased in specific IgG antibodies, bactericidal activities of serum, and CD4+ and CD8+ T-cell population. Antigenic Lm proteins reacted with antisera against HCl- and NOH-induced LMGs, respectively. Bacterial loads in HCl- and NaOH-induced LMGs immunized mice were significantly lower than PBS-injected mice after virulent Lm challenges. It suggested that vaccination with LMGs induces both humoral and cell-mediated immune responses and protects against virulent challenges.

Prokaryotic expression and polyclonal antibody preparation of human adenovirus type 7 DNA binding protein

Objective: To express DNA-binding protein (DBP) of human adenovirus (HAdV) type 7 using the prokaryotic expression system, and product anti-HAdV-7 DBP rabbit polyclonal antibody. Methods: The HAdV-7 DBP gene was synthesized and cloned into prokaryotic expressing vector pET30a, and the recombinant plasmid was transformed into E. coli BL21 (DE3) competent cell. The recombinant protein DBP was expressed by induced Isopropyl-beta-D-thiogalactopyranoside (IPTG) and purified with Ni-NTA affinity column. The titer of anti-DBP polyclonal antibody produced in immunized rabbit was measured by indirect ELISA, and the specificity of the antibody was identified by Western blotting and indirect immunofluorescence assay (IFA). In addition, purified rDBP was used as coating antigen for indirect ELISA assay to detect specific IgM and IgG antibodies against DBP in the serum of children infected with HAdV. Results: The HAdV-7 DBP plasmid was constructed successfully. The purified recombinant DBP was more than 95% after purification. The titer of polyclonal antibody was 1∶1 024 000. The polyclonal antibody showed high specificity in vitro using Western blotting and IFA. The positive rate of specific anti-DBP IgM and IgG antibody in acute-phase serum samples collected from children infected with HAdV were 50.0% (19/38) and 63.2% (24/38), respectively, using indirect ELISA. Conclusion: In summary, the HAdV-7 rDBP is expressed using prokaryotic expression system, and the recombinant HAdV-7 DBP protein and the anti-DBP rabbit polyclonal antibody with high titer are prepared.

Hidden fraction of Polish population immune to SARS-CoV-2 in May 2021.

Population immunity (herd immunity) to SARS-CoV-2 derives from two sources: vaccinations or cases of infection with the virus. Infections can be diagnosed as COVID-19 and registered, or they can be asymptomatic, oligosymptomatic, or even full-blown but undiagnosed and unregistered when patients recovered at home. Estimation of population immunity to SARS-CoV-2 is difficult and remains a subject of speculations. Here we present a population screening for SARS-CoV-2 specific IgG and IgA antibodies in Polish citizens (N = 501) who had never been positively diagnosed with or vaccinated against SARS-CoV-2. Serum samples were collected in Wrocław (Lower Silesia) on 15th and 22nd May 2021. Sera from hospitalized COVID-19 patients (N = 22) or from vaccinated citizens (N = 14) served as positive controls. Sera were tested with Microblot-Array COVID-19 IgG and IgA (quantitative) that contain specific SARS-CoV-2 antigens: NCP, RBD, Spike S2, E, ACE2, PLPro protein, and antigens for exclusion cross-reactivity with other coronaviruses: MERS-CoV, SARS-CoV, HCoV 229E Np, HCoV NL63 Np. Within the investigated population of healthy individuals who had never been positively diagnosed with or vaccinated against SARS-CoV-2, we found that 35.5% (178 out of 501) were positive for SARS-CoV-2-specific IgG and 52.3% (262 out of 501) were positive for SARS-CoV-2-specific IgA; 21.2% of the investigated population developed virus-specific IgG or IgA while being asymptomatic. Anti-RBD IgG, which represents virus-neutralizing potential, was found in 25.6% of individuals (128 out of 501). These patients, though positive for anti-SARS-CoV-2 antibodies, cannot be identified in the public health system as convalescents due to undiagnosed infections, and they are considered unaffected by SARS-CoV-2. Their contribution to population immunity against COVID-19 should however be considered in predictions and modeling of the COVID-19 pandemic. Of note, the majority of the investigated population still lacked anti-RBD IgG protection (74.4%); thus vaccination against COVID-19 is still of the most importance for controlling the pandemic.

Respiratory syncytial virus specific immunoglobulin G4 antibodies and atopic diseases in children.

It has been proposed that RSV infection stimulates RSV specific IgE and IgG4 production as a hallmark of Th2 immune response, which can contribute to the development of allergic sensitization and atopic diseases. This study intends to examine the occurrence of atopic diseases in children (wheezing bronchitis, food allergy, atopic dermatitis) and their connection with RSV specific IgE and IgG4 during the first two years of life. Prospective follow-up from the moment of birth was performed in 127 children with positive RSV specific IgG antibodies at age 1 and 92 children were followed-up until two years of age. The assessment included a structured interview, clinical examination, total blood eosinophils, serum total IgE and allergen specific IgE antibodies, RSV specific IgG, IgG3, IgG4 and IgE antibodies. Significant correlation was found between positive RSV IgG4 antibodies at year one and atopic dermatitis (Tau_b=0.201, P=0.025), as well as food allergy development (Tau_b=0.205, P=0.023). RSV specific IgG4 antibodies to RSV at year one showed significant prediction of increased total and/or allergen specific IgE (odds ratio 2.73 and 95% confidence interval 1.07 - 7.00, P=0.036). In our regression model, the children who had positive RSV IgG4 antibodies had a 2.73 times higher likelihood of having increased positive total and/or allergen specific IgE during the first two years of life. RSV specific IgG4 antibodies could be a marker of risk for the development of atopic sensitization to inhaled and food allergens, development of food allergy and atopic dermatitis in atopic children.

Epidemiological traits of measles in infectious hospital staff

The maximum incidence rates of measles were recorded on the eve of the development of the COVID-19 pandemic in 2019 in many countries of the world, including Russia. One of the features of the epidemic process of this infection in the period from 2011 to 2019 was the involvement of employees of medical organizations (MO) with the formation of large foci. Current features for the development of the measles epidemic situation can be assessed using serological studies. Aim: to assess the epidemiological features of measles in medical workers in Moscow, including by assessing the prevalence of specific IgG antibodies to the measles virus using the example of an infectious disease’s hospital in Moscow. Materials and methods. Using data from state reports on the sanitary and epidemiological well-being of the population in Moscow and form No. 2 of the Federal State Statistical Observation «Information on Infectious and Parasitic Diseases». To study the strength of immunity against measles by the method of enzyme-linked immunosorbent assay (ELISA) using test systems «Vecto-measles IgG» (CJSC «Vector-Best», Russia), 191 blood serum samples from the collection of the Department of Epidemiology of the National Research Center for Epidemiology were examined and Microbiology named after Honorary Academician N. F. Gamaleya (Moscow), taken from the employees of the infectious hospital of the city of Moscow (aged 22 to 65 years) with a different vaccination history. Positive (seropositive) was considered the result of a study of the level of IgG antibodies to measles virus more than 0.18 IU / ml. Results. A feature of the epidemic process of measles in Moscow (for the period from 2014 to 2020) was the annual (except for 2016) registration of measles cases among medical workers and hospital patients of various profiles (in 2019–2020, only among patients). Reasonable doubts about the reliability of the vaccination coverage of the population according to official statistics (exceeds the level of 95 % since 2013), including medical workers, arise due to the availability of data on the previous vaccination in some cases of measles. Measles vaccination data were recorded in 28 people (4.7 %) out of 191 surveyed. In two of them, antibodies to the measles virus could not be detected, and the median of their level in seropositive individuals was 1.75 IU / ml (0.5; 3.0). 10 health workers had a history of measles in the past, which was confirmed by serological examination (the level of IgG antibodies was higher than 3.3 IU / ml). 152 people (79.6 %) had no information about vaccination and measles in the past. Among them, eight people were seronegative (5.3 %), and the level of antibodies in the seropositive was higher than in the vaccinated, and amounted to 2.4 IU / ml [0.74; 3.68]. Conclusion. It was found that the proportion of seronegative among the surveyed individuals did not exceed 7 %. However, the predominance of individuals with a low level of immunity, both among vaccinated and unvaccinated individuals, indicates the need for periodic serological studies for the timely detection of seronegative individuals.

Detection of serum antibodies to tick-borne and other infections in patients with lymphadenopathy

The aim was to determine the prevalence of serum antibodies to tick-borne pathogens and other infectious agents in patients with lymphadenopathy. Materials and methods. 68 patients with lymphadenopathy aged 20 to 63 years who received outpatient or inpatient treatment were followed up at Ternopil University Hospital and Ternopil Regional Clinical Dermatological and Venereological Dispensary. There were 41 women (60.3 %) and 27 men (39.7 %). Two-stage serological detection (ELISA and immunoblot) was used for diagnosis of Lyme borreliosis (LB). Indirect immunofluorescence, including the BIOCHIP multiplex indirect immunofluorescence technique, was used for serological identification of human granulocytic anaplasmosis (HGA) and other infectious diseases, which could be associated with lymphadenopathy. Results. In total, 45.6 % of 68 enrolled patients were positive for the presence of specific antibodies IgM and/or IgG against B. burgdorferi s. l. Further examination demonstrated the presence of specific serum anti-A. phagocytophilum antibodies IgM and/or IgG in 33 patients with lymphadenopathy. It was found that 24.2 % of involved patients were positive for the presence of at least one type of anti-A. phagocytophilum antibodies; 12.1 % had positive or intermediate results only for B. burgdorferi s. l.; 60.6 % of patients were positive for the presence of antibodies against both pathogens. 46.9 % of patients were seropositive for EBV-CA, 40.6 % – for Parainfluenza virus type 1, 37.5 % – for HHV-6, 34.4 % – for HSV-1, 31.3 % – for EBV-EA and Toxoplasma gondii, 6.3 % – for Coxsackievirus type A9 and HIV-2. Conclusions. One-third of all involved patients with lymphadenopathy were positive for antibodies to B. burgdorferi s. l., causa tive agent of Lyme borreliosis. Co-infection of Lyme borreliosis and human granulocytic anaplasmosis was established in more than half of the patients. Besides, specific antibodies to 18 causative agents of other infectious diseases were detected with varying rate. Almost half of positive results detected were the antibodies to parainfluenza virus type 1 and Epstein–Barr virus.

Patterning Large-Scale Nanostructured Microarrays on Coverslip for Sensitive Plasmonic Detection of Aqueous Gliadin Traces

User-friendly devices for detecting low gliadin content in commercial foods are of extreme importance for people with gluten diseases. With this concern, the present work proposes a rapid and sensitive optical nanostructured microarrays platform for the detection of gliadin using specific anti-gliadin IgG antibodies immobilized on annealed gold nanostructures (AuNPs) obtained after the high annealing process (550 °C) of gold thin films evaporated on commercial glass coverslips. Localized Surface Plasmon Resonance (LSPR) immunosensing of gliadin in the range of 0.1 ppm to 1000 ppm is successfully achieved. In addition, the biofunctionalization protocol was used for gluten screening in five food complex products.

Neutralizing antibody response and associated factors in Coronavirus-19 disease (COVID-19) up to one month

Abstract Background There is a knowledge gap about the characteristics of neutralizing antibody (NAb) response in patients who recovered COVID-19. In this study, it is aimed to elucidate the factors affecting the presence and titers of antibodies up to 30-days after onset. Material and methods A total of 129 laboratory-confirmed COVID-19 patients were enrolled. Clinical data were obtained retrospectively. SARS-CoV-2 specific NAb, IgM, and IgG antibody responses were analyzed. Results SARS-CoV-2 specific NAb, IgM and IgG, were detected at the time of hospital discharge in 60.5%, 30.2%, and 51.9% of the patients, respectively. The median time for obtaining serum samples for antibody tests after symptoms’ onset was 11 days. The median titer of neutralizing antibody (SN50) was significantly higher in severe patients (25 vs. 7.5, p=0.009). Of the 23 severe patients, 52.2% (n=12) had higher NAb titers (i.e., SN50≥1:25) when compared to that in non-severe patients (OR=2.89; 95%CI=1.15–7.28, p=0.021), yet, the potential effect of follow-up time on NAb status and titers could not be ruled out. Conclusions The presence of antibody response is not the only determinative factor for recovery. The presence and higher titers of NAb were detected more in severe patients than their non-severe counterparts. Survival analysis suggested that this difference could at least be partially explained by the length of follow-up through antibody testing (at discharge) after symptoms’ onset.

SARS-CoV-2 mRNA vaccine induces robust specific and cross-reactive IgG and unequal neutralizing antibodies in naive and previously infected people

Understanding vaccine-mediated protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is critical to overcoming the global coronavirus disease 2019 (COVID-19) pandemic. We investigate mRNA-vaccine-induced antibody responses against the reference strain, seven variants, and seasonal coronaviruses in 168 healthy individuals at three time points: before vaccination, after the first dose, and after the second dose. Following complete vaccination, both naive and previously infected individuals developed comparably robust SARS-CoV-2 spike antibodies and variable levels of cross-reactive antibodies to seasonal coronaviruses. However, the strength and frequency of SARS-CoV-2 neutralizing antibodies in naive individuals were lower than in previously infected individuals. After the first vaccine dose, one-third of previously infected individuals lacked neutralizing antibodies; this was improved to one-fifth after the second dose. In all individuals, neutralizing antibody responses against the Alpha and Delta variants were weaker than against the reference strain. Our findings support future tailored vaccination strategies against emerging SARS-CoV-2 variants as mRNA-vaccine-induced neutralizing antibodies are highly variable among individuals.

Prolonged SARS-CoV-2 nucleic acid conversion time in military personnel outbreaks with presence of specific IgG antibodies.

Coronavirus disease 2019 (COVID-19) is transmitted person-to-person mainly by close contact or droplets from respiratory tract. However, the actual time of viral shedding is still uncertain as well as the different routes of transmission. We aimed to characterize RNA shedding from nasopharyngeal and rectal samples in prolonged cases of mild COVID-19 in young male soldiers. Seventy patients from three different military locations were monitored after recommending to follow more strict isolation measures to prevent the spread of the virus. Then, nasopharyngeal, rectal, and blood samples were taken. SARS-CoV-2 RNA was detected by RT-PCR and specific antibodies by chemiluminescent immunoassays. The median nucleic acid conversion time (NACT) was 60 days (IQR: 7–85 days). Rectal swabs were taken in 60 % of patients. Seven patients (10 %) were positive in nasopharyngeal and rectal swabs, and five (7.14 %) remained positive in rectal swabs, but negative in nasopharyngeal samples. Four patients (5.71 %) that had been discharged, were positive again after 15 days. No significant difference was found in nucleic acid conversion time between age groups nor clinical classification. Maintaining distancing among different positive patients is essential as a possible re-exposure to the virus could cause a longer nucleic acid conversion time in SARS-COV-2 infections.

SARS-CoV-2 seroprevalence in Portugal following the third epidemic wave: results of the second National Serological Survey (ISN2COVID-19)

Background Integrated approaches to surveillance of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection are important for public health actions. The 2nd National Serological Survey (ISN2COVID-19) aimed to characterize the extent of SARS-CoV-2 infection and vaccine-induced response in the Portuguese population following the third epidemic wave and the launch of the vaccination campaign. Methods A cross-sectional study was performed using data on 8463 Portuguese 1–79 years of age, collected in February and March, 2021. SARS-CoV-2 IgM and IgG (anti-nucleoprotein and anti-spike) antibodies were determined in serum samples using Abbott Architect chemiluminescent microparticle assays. Post-infection and vaccine-induced seroprevalence with 95% confidence intervals (95%CI) were estimated in the overall sample and stratified by population characteristics. Results The estimated seroprevalence was 15.5% (95%CI:14.6–16.5%), of which 13.5% (95%CI: 12.6–14.4%) was attributable to natural infection and 2.0% (95%CI:1.7–2.4%) to vaccination. The lowest seroprevelence was observed in persons aged 70–79 years (8.9% 95%CI:6.8–11.6), while seroprevalence in children (14.3%; 95%CI:11.5–17.6%) and adolescents (12.9%; 95%CI:10.5–15.7%) was similar to that of persons aged between 20 and 69 years. Of seropositive individuals, 22.6% (95%CI:19.7–25.9%) did not report any symptoms in 6 months prior to interview. Of persons with completed vaccination (2-doses), 98.6% (95%CI: 93.0–99.7%) had specific IgG (anti-S) antibodies. Conclusions After the third epidemic wave, the post-infection SARS-CoV-2 seroprevalence was 1.7 times higher than the cumulative incidence based on PCR-testing, but was higher (2.7 times) in children may be due to the high proportion of asymptomatic and mild infections.

Impact of the COVID-19 infection on the “benign” nature of the illness of Schönlein-Henoch

The incidence of COVID-19 in children has been variable. Although now the number of infected children worldwide, and in particular nationally, is small, they are not protected from the infection. Moreover, in the most severe cases septic shock, metabolic acidosis, irreversible bleeding, and coagulation dysfunction have been registered. In February 2021 a 17-year-old boy showed for examination with complaints of pain in the upper part of the abdomen, accompanied by involvement of the ankle joints, the appearance of a rash on the lower extremities with the characteristic of hemorrhagic vasculitis, and a positive test for COVID-19. The characteristics of the skin purpura, the abdominal pain, and the arthralgia led us to the diagnosis of Schönlein-Henoch purpura. The verification of past COVID-19 infection was done by the established high titer of specific IgG antibodies. The clinical evolution of the disease went beyond its generally accepted benign nature - the first manifestation of the illness had been followed by four more relapses, which necessitated new hospitalizations and a change in the therapeutic approach. COVID-19 infection is the cause of a more aggressive course of vasculitis.