Age-dependent distribution of IgA and IgG antibody-secreting cells in the pharyngeal tonsil of the Bactrian camel.

The pharyngeal tonsil, located in the nasopharynx, can effectively defend against pathogens invading the body from the upper respiratory tract and play a crucial role in mucosal immunity of the respiratory tract. Immunoglobulin A (IgA) and Immunoglobulin G (IgG) serve as key effector molecules in mucosal immunity, exhibiting multiple immune functions. This study aimed to investigate the distribution patterns and age-related alterations of IgA and IgG antibody-secreting cells (ASCs) in the pharyngeal tonsils of Bactrian camels. Twelve Alashan Bactrian camels were categorized into four age groups: young (1-2 years, n=3), pubertal (3-5 years, n=3), middle-aged (6-16 years, n=3) and old (17-20 years, n=3). The distribution patterns of IgA and IgG ASCs in the pharyngeal tonsils of Bactrian camels of different ages were meticulously observed, analyzed and compared using immunohistochemical and statistical methods. The results revealed that IgA ASCs in the pharyngeal tonsils of all age groups were primarily clustered or diffusely distributed in the reticular epithelium and its subepithelial regions (region A) and around the glands (region C), scattered in the subepithelial regions of non-reticular epithelium (region B), and sporadically distributed in the interfollicular regions (region D). Interestingly, the distribution pattern of IgG ASCs in the pharyngeal tonsils closely mirrored that of IgA ASCs. The distribution densities of IgA and IgG ASCs in these four regions were significantly decreased in turn (P<0.05). However, IgA ASCs exhibited significantly higher densities than IgG ASCs in the same region (P<0.05). Age-related alterations indicated that the distribution densities of IgA and IgG ASCs in each region of the pharyngeal tonsils exhibited a trend of initially increasing and subsequently decreasing from young to old camels, reaching a peak in the pubertal group. As camels age, there was a significant decrease in the densities of IgA and IgG ASCs in all regions of the pharyngeal tonsils (P<0.05). The results demonstrate that the reticular epithelium and its subepithelial regions in the pharyngeal tonsils of Bactrian camels are the primary regions where IgA and IgG ASCs colonize and exert their immune functions. These regions play a pivotal role in inducing immune responses and defending against pathogen invasions in the pharyngeal tonsils. IgA ASCs may be the principal effector cells of the mucosal immune response in the pharyngeal tonsils of Bactrian camels. Aging significantly reduces the densities of IgA and IgG ASCs, while leaving their distribution patterns unaffected. These findings will provide valuable insights for further investigations into the immunomorphology, immunosenescence, and response mechanisms of the pharyngeal tonsils in Bactrian camels.

Development and evaluation of a Lateral flow immunoassay (LFIA) prototype for the detection of IgG anti-SARS-CoV-2 antibodies.

Lateral flow immunoassays (LFIA) for antibody detection represent cost-effective and user-friendly tools for serology assessment. This study evaluated a new LFIA prototype developed with a recombinant chimeric antigen from the spike/S and nucleocapsid/N proteins to detect anti-SARS-CoV-2 IgG antibodies. The evaluation of LFIA sensitivity and specificity used 811 serum samples from 349 hospitalized, SARS-CoV-2 RT-qPCR positive COVID-19 patients, collected at different time points and 193 serum samples from healthy controls. The agreement between ELISA results with the S/N chimeric antigen and LFIA results was calculated. The LFIA prototype for SARS-CoV-2 using the chimeric S/N protein demonstrated 85 % sensitivity on the first week post symptoms onset, reaching 94 % in samples collected at the fourth week of disease. The agreement between LFIA and ELISA with the same antigen was 92.7 %, 0.827 kappa Cohen value (95 % CI [0.765-0.889]). Further improvements are needed to standardize the prototype for whole blood use. The inclusion of the novel chimeric S + N antigen in the COVID-19 IgG antibody LFIA demonstrated optimal agreement with results from a comparable ELISA, highlighting the prototype's potential for accurate large-scale serologic assessments in the field in a rapid and user-friendly format.

Persistence of IgG and neutralizing antibodies in Crimean-Congo hemorrhagic fever survivors.

The World Health Organization classified Crimean-Congo hemorrhagic fever (CCHF) as a high-priority infectious disease and emphasized the performance of research studies and product development against it. Little information is available about the immune response due to natural CCHF virus (CCHFV) infection in humans. Here, we investigated the persistence of IgG and neutralizing antibodies in serum samples collected from 61 Iranian CCHF survivors with various time points after recovery (<12, 12-60, and >60 months after disease). The ELISA results showed IgG seropositivity in all samples while a pseudotyped based neutralization assay findings revealed the presence of neutralizing antibody in 29 samples (46.77%). For both IgG and neutralizing antibodies, a decreasing trend of titer was observed with the increase in the time after recovery. Not only the mean titer of IgG (772.80 U/mL) was higher than mean neutralizing antibody (25.64) but also the IgG persistence was longer. In conclusion, our findings provide valuable information about the long-term persistence of humoral immune response in CCHF survivors indicating that IgG antibody can be detected at least 8 years after recovery and low titers of neutralizing antibody can be detected in CCHF survivors.

Clinicomycological Study of the Spectrum of Pulmonary Aspergillosis at a Tertiary Care Hospital in Central India.

Knowing the spectrum, prevalence, and modes of diagnosis of pulmonary aspergillosis (PA) will be beneficial to clinicians for its early diagnosis and management. This study aims to estimate the prevalence, spectrum, and role of serological tests and radiological findings in the diagnosis of PA. A total of 150 patients were suspected of having PA after obtaining relevant clinical history and radiological imaging. The patients were grouped into each spectrum of PA as invasive PA (IPA), chronic necrotizing PA (CNPA), aspergilloma, allergic bronchopulmonary aspergillosis (ABPA) based on predisposing factors, clinical and radiological findings, and the guidelines of the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG). Samples (bronchoalveolar lavage (BAL), sputum, blood) were collected from these patients and processed in a microbiology lab. BAL and sputum were subjected to microscopy by potassium hydroxide mount, calcofluor white mount, and culture. The serum was separated from blood by centrifugation and subjected to specific serological tests based on the spectrum of PA that the patient was suspected to have. For IPA, serum and BAL galactomannan antigen enzyme-linked immunosorbent assay (ELISA) was performed. For CNPA and aspergilloma, the anti-Aspergillus IgG antibody ELISA was performed. For ABPA, the tests performed were total immunoglobulin E (IgE) ELISA, Aspergillus fumigatus-specific IgE ELISA, and anti-Aspergillus immunoglobulin G (IgG) antibody ELISA. After compiling the clinical, radiological, culture, and serological findings, patients were diagnosed to have a particular spectrum of PA. The prevalence of IPA was 1.4%, CNPA was 4%, ABPA was 3.2%, and aspergilloma was 2.9%. CNPA was the predominant spectrum of PA in our study. Culture positivity for Aspergillus species was seen the highest in aspergilloma patients, followed by IPA, ABPA, and CNPA patients. A. fumigatus was the most common causative agent of PA, except for IPA for which Aspergillus flavus was the most common causative. Aspergillus niger and Aspergillus terreus were less the frequent causes of PA. A combination of radiological, microbiological, and serological tests along with clinical correlation is needed to confirm the diagnosis of PA.

Durability of COVID-19 humoral immunity post infection and different SARS-COV-2 vaccines.

BACKGROUND: The global challenge posed by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been a major concern for the healthcare sector in recent years. Healthcare workers have a relatively high risk of encountering COVID-19 patients, making protective immunity against SARS-CoV-2 is a priority for them. This study aims to evaluate the longitudinal measurement of SARS-CoV-2 IgG spike protein antibodies in healthcare workers (HCWs) after COVID-19 infection and after receiving the first and second doses of SARS-CoV-2 vaccines, including Pfizer-BioNTech (BNT162b2) and Oxford-AstraZeneca (AZD1222). METHODS: This longitudinal cohort study involved 311 healthcare workers working in two tertiary hospitals in Saudi Arabia. All participants were followed between July 2020 and July 2022 after completing the study questionnaire. A total of 3 ml of the blood samples were collected at four intervals: before/after vaccination. RESULTS: HCWs post-infection had lower mean SARS-CoV-2 IgG levels three months post-infection than post-vaccination. 92.2% had positive IgG levels two weeks after the first dose and reached 100% after the second dose. Over 98% had positive antibodies nine months after the second dose, regardless of vaccine type. The number of neutralizing antibodies decreased and was around 50% at nine months after the second dose. CONCLUSION: The results show different antibody patterns between infected and vaccinated HCWs. A high proportion of participants had positive antibodies after vaccination, with high levels persisting nine months after the second dose. Neutralizing antibodies decreased over time, with only about 50% of participants having positive antibodies nine months after the second dose. These results contribute to our understanding of immunity in healthcare workers and highlight the need for the continuous monitoring and possible booster strategies.

High diagnostic accuracy of quantitative SARS-CoV-2 spike-binding-IgG assay and correlation with in vitro viral neutralizing activity.

Background: Antibody testing can easily evaluate the clinical status of patients, aid in the diagnosis of multisystem inflammatory syndrome, and monitor the immunity level in the population. However, the applicability of serological tests in detecting antibodies against the severe acute respiratory syndrome 2 (SARS-CoV-2) spike-binding protein remains limited. This study aimed to quantify both serum-derived neutralizing immunoglobulin-G (IgG) antibody activity and the amount of anti-SARS-CoV-2 Spike-IgG (S-IgG) in convalescent sera/plasmas and evaluate the direct correlation between the in vitro IgG-EC50 values and S-IgG values. Methods: We evaluated the neutralizing activity of purified IgG (IgG-EC50), quantified S-IgG in the serum/plasma of consecutive COVID-19 convalescent individuals using a cell-based virus-neutralizing assay, and determined the correlation between IgG-EC50 and S-IgG. In addition, we evaluated rational cut-off values using the receiver operating characteristic (ROC) curve and calculated the sensitivity and specificity of the quantitative S-IgG assay for moderate and high IgG-EC50. Results: A high correlation was observed between S-IgG and IgG-EC50 with a Spearman's ρ value of -0.748 (95 % confidence interval [CI]: -0.804-0.678). Using an IgG-EC50 of 50 µg/mL and 20 µg/mL as the cut-off values for moderate and high in vitro neutralizing activity, respectively, the Youden's index values of 287.5 binding antibody units (BAU)/mL and 454.1 BAU/mL determined from the ROC curve showed the highest diagnostic accuracy, with Kappa values of 0.884 (95 % CI: 0.823-0.946) and 0.920 (95 % CI: 0.681-0.979), respectively. Conclusions: Quantitative S-IgG tests are a useful and convenient tool for estimating in vitro virus-neutralizing activity, with a high correlation with IgG-EC50 when the rational cut-off value is carefully determined.

Optimal timing of SARS-CoV-2 vaccination prior to cardiovascular surgery under cardiopulmonary bypass.

BACKGROUND: mRNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became common. We investigated the optimal timing for inoculation against SARS-COV-2 in the candidates for cardiac surgery under cardiopulmonary bypass (CPB). METHODS: In 100 patients with preoperative vaccination, who underwent CPB surgery between July 2021 and February 2022, the IgG against the receptor binding domain (RBD-IgG), with a threshold of >100 binding antibody unit (BAU)/mL for adequate immunity, was measured. RESULTS: The vaccines, including 87 BNT162b2 (Pfizer/BioNTech) and 13 mRNA-1273 (Moderna), were inoculated at 98.8 ± 59.4 days before surgery. The median RBD-IgG titers before surgery, 1 day after surgery, and 1 month after surgery were 166.8, 100.0, and 84.0 BAU/mL, respectively. The standby interval (SBI) from the vaccination to the surgery showed a significantly negative correlations with the RBD-IgG titer before the surgery (p < 0.001). A cut-off SBI for RBD-IgG >100 BAU/mL before surgery was <81 days with a sensitivity of 76%, specificity of 62%, and area under ROC value of 0.73 (p = 0.03). The patients with SBI <81 days (n = 48) had significantly higher RBD-IgG (>100 BAU/mL) than those with SBI ⩾81 days (n = 52) at all perioperative periods. CONCLUSIONS: Although 40% of the RBD-IgG titers reduce 1 day after CPB surgery, the patients who received the SARS-COV-2 vaccination within an 81-day window prior to the surgery maintained a desirable RBD-IgG level, even up to 1 month after surgery. It may be important to schedule the surgery no later than 81 days after the vaccination.

Safety and immunogenicity of homologous prime-boost CoronaVac vaccine in people living with HIV in China: A multicenter prospective cohort study.

People living with HIV (PLWH) are particularly vulnerable to SARS-CoV-2. This multicentre prospective cohort study evaluated the long-term immunogenicity and safety of a third homologous dose of Sinovac CoronaVac in PLWH in China. A total of 228 PLWH and 127 HIV-negative controls were finally included and followed up for 6 months. Fewer participants reported mild or moderate adverse reactions, and no serious adverse events were observed. The median levels of neutralizing antibodies (nAbs) and immunoglobulin G against the receptor-binding domain of the spike protein (S-IgG) in PLWH (655.92 IU/mL, IQR: 175.76-1663.55; 206.83 IU/mL, IQR: 85.20-397.82) were comparable to those in control group (1067.16 IU/mL, IQR: 239.85-1670.83; 261.70 IU/mL, IQR: 77.13-400.75), and reached their peak at 4 weeks, exhibiting a delayed peak pattern compared to the 2-week peak in control group. After then, the immune titres gradually decreased over time, but most participants still maintained positive seroconversion at the 6-month mark. Multivariable generalized estimating equation analysis indicated that CD4+T cell count, HIV viral load, and antiretroviral therapy (ART) were independent factors strongly associated with immune response (each p < 0.05). We suggested that PLWH should maintain well-controlled HIV status through ART and receive timely administration of the second booster dose for optimal protection.

A Survey on Handling and Administration of Therapeutic Protein Products in German and Swiss Hospitals.

Protein products in hospitals often have to be compounded before administration to the patient. This may comprise reconstitution of lyophilizates, dilution, storage, and transport. However, the operations for compounding and administration in the hospital may lead to changes in product quality and possibly even impact patient safety. We surveyed healthcare practitioners from three clinical units using a questionnaire and open dialogue to document common procedures and their justification and to document differences in handling procedures. The survey covered dose compounding, transportation, storage and administration. One key observation was that drug vial optimization procedures were used for some products, e.g., use of one single-use vial for several patients. This included the use of spikes and needles or closed system transfer devices (CSTDs). Filters or light protection aids were used only when specified by the manufacturer. A further observation was a different handling of the overfill in pre-filled infusion containers, possibly impacting total dose. Lastly, we documented the complexity of infusion administration setups for administration of multiple drugs. In this case, flushing procedures or the placement and use of filters in the setup vary. Our study has revealed important differences in handling and administration practice. We propose that drug developers and hospitals should collaborate to establish unified handling procedures.

Immunogenicity evaluation of prototype and variant inactivated SARS-CoV-2 vaccines in rats / 中国生物制品学杂志

@#Objective To evaluate the immunogenicity of prototype strain,Beta strain,Gamma strain and Delta strain of SARS-CoV-2 inactivated vaccines in rats.Methods Five female Wistar rats were immunized with SARS-CoV-2 inactivated vaccines of prototype,Beta,Gamma and Delta strains through thigh muscle twice at an interval of 14 d,with an immunization dose of 3 μg virus protein/(0.5 mL per rat).Serum samples were collected and isolated by vein 14,28 and 42 d after the first immunization.The serum IgG antibody levels were detected by indirect ELISA,the titers of serum neutralizing antibody were measured by microneutralization,and the antigenic ratios of the serum neutralizing antibody titers were calculated to evaluate the antigenicity difference between different strains.Results at 14 d after the first immunization,IgG antibodies against four strains of virus were detected in all immunized serum samples.The levels of IgG antibodies increased by more than 10 times at 28 d compared with those at 14 d,and decreased slightly at 42 d.At 14 d after the first immunization,all the neutralizing antibodies against the four strains were positive in the serum of rats immunized with prototype strain or Delta strain vaccine;In the serum samples of rats immunized with Beta and Gamma strains,all the neutralizing antibodies against Beta and Gamma strains were positive,while some neutralizing antibodies against prototype or Delta strains were positive.At 28 d after the first immunization,the neutralizing antibodies in the immune serum of the four strains were positive,and the titers of neutralizing antibodies were significantly higher than those at 14 d;The neutralizing antibody titers were slightly lower at 42 d after the first immunization than 28 d.There was small difference in the antigenicity between Beta and Gamma,prototype and Gamma,but significant difference in the antigenicity between prototype and Beta strains.Conclusion The prototype strain,Beta strain,Gamma strain and Delta strain of SARS-CoV-2 inactivated vaccines can stimulate rats to produce neutralizing antibodies with high titer,while the immunogenicity has difference.

Baseline Pneumococcal IgG Levels and Response to 23-Valent Pneumococcal Polysaccharide Vaccine among Adults from Beijing, China.

PURPOSE: To investigate the baseline levels of serotype-specific IgG antibodies to Streptococcus pneumoniae (S. pneumoniae) and assess their impact on the assessment of vaccine immunogenicity. METHODS: We used a subset of serum samples from a randomized controlled trial. The blood of 584 healthy participants was collected on day 0 before and day 28 after the 23-valent pneumococcal polysaccharide vaccine (PPSV23) vaccination. Serotype-specific IgG against PPSV23-covered serotypes were measured by the World Health Organization (WHO) reference enzyme-linked immunosorbent assay (ELISA). Vaccine immunogenicity was compared using conversion rates (proportion of participants with IgG levels following immunization that are 2-fold greater than the baseline) and geometric mean fold rises (GMFRs) between the two groups, which were grouped according to pre-vaccination (baseline) IgG antibody levels. RESULTS: Our data showed that over half of individuals have baseline IgG levels for 15 out of 23 serotypes above 1.3 µg/mL, and geometric mean concentrations (GMCs) were generally higher in the elderly group and the female group; significant differences were found in 15 serotypes for vaccine immunogenicity based on the seroconversion rate or GMFRs between individuals with baseline IgG ≥ 1.3 µg/mL and individuals with baseline IgG < 1.3 µg/mL. The seroconversion rate decreased with the increase of baseline IgG levels according to a linear regression model. CONCLUSIONS: The assessment of vaccine immunogenicity could be impacted by the fact that many adults had high baseline antibody levels. This study is registered in the Chinese Clinical Trial Registry, number NCT05298800.

Association between toxoplasmosis and autoimmune rheumatic diseases in Egyptian patients.

PURPOSE: To explore the association between T. gondii and autoimmune rheumatic diseases (ARDs). METHODS: This study involved 82 patients with ARDs: 44 rheumatoid arthritis (RA), 28 systemic lupus erythematosus (SLE), and 10 systemic sclerosis (SSc) and 61 age- and sex-matched controls. Sociodemographic, clinical, and laboratory data were collected, and disease activity was assessed. Exposure to toxoplasmosis risk factors was investigated. Serological tests for anti-Toxoplasma IgM and IgG antibodies were assessed using ELISA. RESULTS: In SLE patients, a significant difference of T. gondii IgM versus controls was detected (P=.03). In RA and SLE patients, T. gondii IgG showed a significant difference versus controls (34 (77.3%) P=.001 and 18 (64.3%) P=.03, respectively). There was no significant difference in SSc versus controls. Fetal congenital anomalies displayed a significant difference in IgM seropositive compared to seronegative patients (P=.04). Cat exposure showed a significant difference between IgM and IgG seropositive versus seronegative patients (12 (80.0%) P=.02 and 34 (59.6) P=.04, respectively). There was no significant difference in seropositive patients regarding history of abortion, neuro-psychiatric manifestations, disease activity parameters (ESR, CRP), or different regimens of medications. CONCLUSION: Toxoplasma IgM seropositivity is associated with SLE patients. T. gondii IgG seropositivity is associated with both RA and SLE patients. However, Toxoplasma seropositivity had no association with SSc patients. An association between fetal congenital anomalies and IgM seropositivity was demonstrated. A linkage between cat exposure as a risk factor and toxoplasmosis was suggested among ARD patiants. Exploration of impact of toxoplasmosis on ARDs is a necessity through randomized controlled trials.

COVID-19 Antibody Seroconversion in Cancer Patients: Impact of Therapy Cessation-A Single-Center Study.

BACKGROUND: The effective development of COVID-19 vaccination has mitigated its harm. Using two laboratory methods, we investigated the efficacy of the BNT162b2 mRNA and BBIBP-CorV COVID-19 vaccines on seroconversion rates in cancer patients undergoing active cancer treatment. METHODS: SARS-CoV-2 vaccines were scheduled for 134 individuals. The consenting participants submitted three venous blood samples. Three samples: T0, T1, and T2. The ABBOTT-SARS-CoV-2 IgG II Quant and Elecsys® Anti-SARS-CoV-2 assays were used to evaluate the samples and convert the antibody titers to WHO (BAU)/mL units. RESULTS: Cancer patients exhibited a higher seroconversion rate at T2, regardless of vaccination type, and the mean antibody titers at T1 and T2 were higher than those at T0. BBIBP-CorV patients required a booster because BNT162b2 showed a higher seroconversion rate between T0 and T1. Statistics indicate that comparing Abbott and Roche quantitative antibody results without considering the sample collection time is inaccurate. CONCLUSIONS: COVID-19 vaccines can still induce a humoral immune response in patients undergoing cancer-targeted therapy. The strength of this study is the long-term monitoring of antibody levels after vaccination in cancer patients on active therapy using two different immunoassays. Further multicenter studies with a larger number of patients are required to validate these findings.

Association between toxoplasmosis and autoimmune rheumatic diseases in Egyptian patients / Asociación entre toxoplasmosis y enfermedades reumáticas autoinmunes en pacientes egipcios

Purpose: To explore the association between T. gondii and autoimmune rheumatic diseases (ARDs). Methods: This study involved 82 patients with ARDs: 44 rheumatoid arthritis (RA), 28 systemic lupus erythematosus (SLE), and 10 systemic sclerosis (SSc) and 61 age- and sex-matched controls. Sociodemographic, clinical, and laboratory data were collected, and disease activity was assessed. Exposure to toxoplasmosis risk factors was investigated. Serological tests for anti-Toxoplasma IgM and IgG antibodies were assessed using ELISA. Results: In SLE patients, a significant difference of T. gondii IgM versus controls was detected (P=.03). In RA and SLE patients, T. gondii IgG showed a significant difference versus controls (34 (77.3%) P=.001 and 18 (64.3%) P=.03, respectively). There was no significant difference in SSc versus controls. Fetal congenital anomalies displayed a significant difference in IgM seropositive compared to seronegative patients (P=.04). Cat exposure showed a significant difference between IgM and IgG seropositive versus seronegative patients (12 (80.0%) P=.02 and 34 (59.6) P=.04, respectively). There was no significant difference in seropositive patients regarding history of abortion, neuro-psychiatric manifestations, disease activity parameters (ESR, CRP), or different regimens of medications. Conclusion: Toxoplasma IgM seropositivity is associated with SLE patients. T. gondii IgG seropositivity is associated with both RA and SLE patients. However, Toxoplasma seropositivity had no association with SSc patients. An association between fetal congenital anomalies and IgM seropositivity was demonstrated. A linkage between cat exposure as a risk factor and toxoplasmosis was suggested among ARD patiants. Exploration of impact of toxoplasmosis on ARDs is a necessity through randomized controlled trials.(AU)

Propósito: Explorar la asociación entre Toxoplasma gondii y enfermedades reumáticas autoinmunes (ERA).Métodos: Este estudio involucró a 82 pacientes con ERA: 44 con artritis reumatoide (AR), 28 con lupus eritematoso sistémico (LES) y 10 con esclerosis sistémica (SSc); y 61 controles emparejados por edad y sexo. Se recopilaron datos sociodemográficos, clínicos y de laboratorio, y se evaluó la actividad de la enfermedad. Se indagó exposición a factores de riesgo de toxoplasmosis. Las pruebas serológicas de anticuerpos IgM e IgG antitoxoplasma se evaluaron mediante ELISA.Resultados: En pacientes con LES se detectó una diferencia significativa de T. gondii IgM vs. controles (p = 0,03). En pacientes con AR y LES, T. gondii IgG mostró una diferencia significativa frente a los controles (34 [77,3%] p = 0,001 y 18 [64,3%] p = 0,03, respectivamente). No hay diferencia significativa en SSc vs. controles. Las anomalías congénitas fetales mostraron una diferencia significativa en los pacientes seropositivos para IgM en comparación con los pacientes seronegativos (p = 0,04). La exposición a los gatos mostró una diferencia significativa entre los pacientes seropositivos para IgM e IgG frente a los seronegativos (12 [80%] p = 0,02 y 34 [59,6] p = 0,04, respectivamente). No hubo diferencias significativas en pacientes seropositivos con respecto a antecedentes de aborto, manifestaciones neuropsiquiátricas, parámetros de actividad de la enfermedad (ESR, CRP) o diferentes regímenes de medicamentos.(AU)

HSP60 mimetic peptides from Mycobacterium leprae as new antigens for immunodiagnosis of Leprosy.

The early diagnosis of leprosy serves as an important tool to reduce the incidence of this disease in the world. Phage display (PD) technology can be used for mapping new antigens to the development of immunodiagnostic platforms. Our objective was to identify peptides that mimic Mycobacterium leprae proteins as serological markers using phage display technology. The phages were obtained in the biopanning using negative and positive serum from household contacts and leprosy patients, respectively. Then, the peptides were synthesized and validated in silico and in vitro for detection of IgG from patients and contacts. To characterize the native protein of M. leprae, scFv antibodies were selected against the synthetic peptides by PD. The scFv binding protein was obtained by immunocapture and confirmed using mass spectrometry. We selected two phase-fused peptides, MPML12 and MPML14, which mimic the HSP60 protein from M. leprae. The peptides MPML12 and MPML14 obtained 100% and 92.85% positivity in lepromatous patients. MPML12 and MPM14 detect IgG, especially in the multibacillary forms. The MPML12 and MPML14 peptides had positivity of 11.1% and 16.6% in household contacts, respectively. There was no cross-reaction in patient's samples with visceral leishmaniasis, tuberculosis and other mycobacteriosis for both peptides. Given these results and the easy obtainment of mimetic antigens, our peptides are promising markers for application in the diagnosis of leprosy, especially in endemic and hyperendemic regions.

Containing anti-PLA2R IgG antibody induces podocyte injury in idiopathic membranous nephropathy.

Background: Idiopathic membranous nephropathy is widely recognized as an autoimmune kidney disease that is accompanied by the discovery of several autoantibodies, and the antibody subclass in the circulation of patients with iMN is mainly IgG. However, the direct pathogenic effect of the containing anti-PLA2R IgG antibody on podocytes is not clear.Method: A protein G affinity chromatography column was used to purify serum IgG antibodies. Containing anti-PLA2R IgG antibodies from iMN patients and IgG from healthy controls were also obtained. Based on the established in vitro podocyte culture system, purified IgG antibodies from the two groups were used to stimulate podocytes, and the expression of essential podocyte proteins (podocin), the levels of inflammatory cytokines in the cell supernatant, cytoskeletal disorders, and podocyte apoptosis were analyzed.Results: Compared with that in the normal IgG group, the expression of podocin and podocin mRNA was reduced (p = 0.016 and p = 0.005, respectively), the fluorescence intensity of podocin on the surface of podocytes was reduced, the cytoskeleton of podocytes was disordered and reorganized, and the ratio of podocyte apoptosis was increased in the iMN group (p = 0.008).Conclusion: The containing anti-PLA2R IgG antibody might have a direct damaging effect on podocytes in idiopathic membranous nephropathy.

Evaluation of Covid-19 anti-spike IgG antibody five months after the second Covid-19 vaccination.

Background: Studies in different communities have shown significant differences in IgG antibody titers in the time period after the first and second doses of the vaccines. This study aimed to serologically evaluate the IgG anti-spike antibody titer five months after injection of the second COVID-19 vaccine in healthcare workers. Materials and method: This study was performed in healthcare personnel for whom five months had passed since their second anti-Covid-19 vaccination. The level of IgG antibody against SARS-CoV-2 spike protein was measured by ELISA. Healthcare workers in Mofid Children's hospital received three brands of vaccines: Sputnik V, Sinopharm, and AstraZeneca. Results: The mean titer of anti-spike IgG was 4.3±2.29 units. The percentage of positive cases of the antibody was estimated to be 96.4%. The titer of anti-spike IgG antibody was dependent on both the occupational area and a positive history of Covid-19 disease. Conclusion: About 96.4% of the staff vaccinated against Covid-19 had a high titer of anti-spike IgG antibody even five months after inoculation of the second dose. The field of occupational can affect the level of antibody present.

SARS-CoV-2 seroprevalence and implications for population immunity: Evidence from two Health and Demographic Surveillance System sites in Kenya, February-December 2022.

BACKGROUND: We sought to estimate SARS-CoV-2 antibody seroprevalence within representative samples of the Kenyan population during the third year of the COVID-19 pandemic and the second year of COVID-19 vaccine use. METHODS: We conducted cross-sectional serosurveys among randomly selected, age-stratified samples of Health and Demographic Surveillance System (HDSS) residents in Kilifi and Nairobi. Anti-spike (anti-S) immunoglobulin G (IgG) serostatus was measured using a validated in-house ELISA and antibody concentrations estimated with reference to the WHO International Standard for anti-SARS-CoV-2 immunoglobulin. RESULTS: HDSS residents were sampled in February-June 2022 (Kilifi HDSS N = 852; Nairobi Urban HDSS N = 851) and in August-December 2022 (N = 850 for both sites). Population-weighted coverage for ≥1 doses of COVID-19 vaccine were 11.1% (9.1-13.2%) among Kilifi HDSS residents by November 2022 and 34.2% (30.7-37.6%) among Nairobi Urban HDSS residents by December 2022. Population-weighted anti-S IgG seroprevalence among Kilifi HDSS residents increased from 69.1% (65.8-72.3%) by May 2022 to 77.4% (74.4-80.2%) by November 2022. Within the Nairobi Urban HDSS, seroprevalence by June 2022 was 88.5% (86.1-90.6%), comparable with seroprevalence by December 2022 (92.2%; 90.2-93.9%). For both surveys, seroprevalence was significantly lower among Kilifi HDSS residents than among Nairobi Urban HDSS residents, as were antibody concentrations (p < 0.001). CONCLUSION: More than 70% of Kilifi residents and 90% of Nairobi residents were seropositive for anti-S IgG by the end of 2022. There is a potential immunity gap in rural Kenya; implementation of interventions to improve COVID-19 vaccine uptake among sub-groups at increased risk of severe COVID-19 in rural settings is recommended.

Validation of the use of dried blood spots in a chikungunya virus IgG serological assay.

Dried blood spot (DBS) sampling is a simple, fast, and minimally invasive blood collection method that is particularly useful for diagnostic or epidemiological studies in hard-to-reach populations. Nevertheless, the use of DBS in assays that have been optimized with gold-standard samples (serum or plasma) must be optimized to yield reliable results. Here, we describe the validation of DBS in a commercial assay to measure IgG against chikungunya virus (CHIKV IgG ELISA; Euroimmun, Lübeck, Germany). During a health survey of people experiencing homelessness in Salvador, Brazil, between September 2021 and February 2022, a subset (75/523; 14.3%) of the study participants had paired capillary (for DBS preparation) and venous (for serum separation) blood samples collected. A pilot optimization test was initially performed with 17 paired samples to compare the CHIKV IgG ELISA absorbance values between serum and three different dilutions of DBS. Based on the preliminary results, the best DBS dilution was selected for a final evaluation comparing paired serum and DBS samples from 58 participants. The sensitivity and specificity of the CHIKV ELISA of DBS compared to sera were 100% (95% C.I.: 85.8-100%) and 100% (95% C.I.: 93-100%), respectively. In the linear regression analysis, a coefficient of determination (R2) value of 0.98 indicated the excellent performance of DBS in predicting the serum levels of IgG CHIKV antibodies. Our findings suggest that DBS at an optimized dilution is reliable for investigating the prevalence of CHIKV IgG antibodies during population surveys in the commercial assay tested here.