Search Results (100)

This study aims to characterise the B cell compartment in a cohort of Sicilian centenarians by analysing absolute CD3⁻CD19⁺ lymphocyte counts, in association with age, sex, cytomegalovirus (CMV) serostatus, related to immune ageing, and interleukin (IL)-6 levels, representative of inflamm-ageing. It also investigates age-related changes in the CD4⁺/CD19⁺ ratio as a marker of immune ageing, reflecting shifts in immune homeostasis. B cell counts were assessed by flow cytometry on 53 Sicilians aged 19–110 years: 20 Adults, 15 Older adults, 11 long-living individuals, and 7 oldest centenarians. A multiple negative binomial regression was applied to evaluate the effects of age, sex, CMV serostatus, and Il-6 levels on values of B cells. The results showed a non-significant trend toward age-related decline without sex-based differences. A significant reduction in B cell count was observed in individuals with high anti_CMV titres, while IL-6 levels showed a borderline inverse correlation. CD4⁺/CD19⁺ ratio values showed an age-related increase. Our findings suggest that the age-related decline in B cell numbers may be mostly related to CMV infection and IL-6 values, without sex contribution. The age-related increase in the CD4⁺/CD19⁺ ratio, most pronounced in oldest centenarians, may represent a compensatory adaptation promoting immune regulation and chronic inflammation control. Full article

Background: Seronegative rheumatoid arthritis (SNRA), defined by the absence of rheumatoid factor (RF) and anti-citrullinated peptide antibodies (ACPA), represents 20–30% of rheumatoid arthritis cases. Once considered a milder phenotype, SNRA is now recognised as a heterogeneous entity in which a substantial subset of patients develops structural progression comparable to seropositive RA. The binary RF/ACPA-based definition is increasingly viewed as insufficient, as the broader anti-modified protein antibody (AMPA) family—including antibodies against carbamylated, acetylated and malondialdehyde–acetaldehyde–modified proteins—indicates that many “seronegative” patients may harbour unconventional humoral autoimmunity undetected by standard assays. Objectives: To synthesise contemporary insights into the epidemiology, immunopathology, diagnostic challenges and therapeutic management of SNRA, with emphasis on erosive versus non-erosive phenotypes and the implications of the AMPA paradigm. Methods: A comprehensive literature search of PubMed, Cochrane Library and Google Scholar identified randomised trials, observational cohorts and systematic reviews, with focus on studies published within the past decade. Results: SNRA displays partially distinct immune features, including lower formation of tertiary lymphoid structures and variable activation of innate inflammatory circuits. However, the traditional adaptive–versus–innate dichotomy is overly reductionist. Growing evidence suggests that unconventional humoral responses directed against non-classical post-translational modifications may be present in a proportion of RF/ACPA-negative patients. Additional qualitative dimensions—such as IgA isotypes and fine-specificity profiles—represent further heterogeneity with potential prognostic significance. Although ACPA remains the strongest predictor of erosive progression, up to one-third of seronegative patients develop erosions within five years. The 2010 ACR/EULAR criteria may delay diagnosis in SNRA. Cytokine inhibitors and JAK inhibitors show largely serostatus-independent efficacy, whereas B-cell and T-cell–targeted therapies demonstrate attenuated responses in SNRA. Conclusions: SNRA is clinically and immunologically diverse. Integrating the AMPA framework is essential for refining classification and prognostication. Distinguishing erosive from non-erosive forms may guide treatment, while future work should prioritise biomarkers predicting progression and therapeutic response. Full article

Background: Anti-N-methyl-D-aspartate IgM and IgA antibodies (NMDAR1-abs) are associated with unfavorable stroke outcomes and may be risk factors thereof. However, to utilize NMDAR1-abs serostatus for risk assessment in acute stroke, it is crucial to understand the robustness of serostatus during this phase. Therefore, we investigated the robustness of NMDAR1-abs serostatus and titer levels up to seven days after stroke. Methods: In this exploratory analysis of the multicenter STRAWINSKI trial (identifier: NCT01264549), patients with severe ischemic stroke (NIHSS ≥ 9) in the middle cerebral artery territory were included. The first blood sample was taken within 36 h and then daily from day two to seven after stroke. NMDAR1-abs immunoglobulin (Ig)A and IgM were assessed in serum using cell-based assays. We initially measured NMDAR1-abs in the total cohort on day 1. Subsequently, in samples from seropositive and matched seronegative patients, we measured NMDAR1-abs on each following day. Titer dilutions started from 1:10 up to 1:1000. Seropositivity was defined as any titer > 0. Results: Out of 171 patients (mean age = 76 [SD = 11], median NIHSS = 15 [IQR = 12–18]), 16 (9%) individuals were seropositive. Seropositive patients remained seropositive and matched seronegative participants remained seronegative over sequential measurements. Although titer levels remained largely unchanged, some patients showed fluctuating titers. Conclusions: The status of NMDAR1-abs seropositivity is stable during acute stroke, with little to no variation in titer levels. Full article

Previous studies have evaluated the association between different blood groups and human infection with Toxoplasma gondii. No similar studies exist in cats. The objective of this study was to evaluate the role of some risk or protective factors, including the AB blood type system phenotypes, in T. gondii infection in cats. Feline sera and surplus EDTA anticoagulated blood samples, for which AB blood group system phenotypes had been determined, were analyzed for T. gondii antibodies (ELISA, cut-off S/P% ≥ 50% and IFAT, cut-off ≥ 1:64) and DNA (nested and real-time PCR). T. gondii status and the characteristics of signalment (gender, breed, and age), lifestyle (stray, shelter, privately-owned), origin (Northern or Southern Italy), and retroviral infection serostatus of the population were evaluated using the Chi-square test, with calculation of the Odds Ratio (OR) in cases of statistically significant association (p < 0.05). A total of 199 samples were analyzed, of which 178 were phenotype A, 15 were phenotype B, and 6 were phenotype AB. Of these, 57/199 (28.6%) were positive for T. gondii: 5 were positive at PCR, 33 at ELISA, and 19 at IFAT. Of the 57 positive cats, 52/57 were phenotype A, 3/57 phenotype B, and 2/57 phenotype AB, with no significant association with T. gondii infection. FIV seropositive cats had a higher risk (OR = 3.1, p = 0.0043) of testing T. gondii positive. This study did not find an association between T. gondii infection and the feline blood types investigated; therefore, based on our results, AB blood group system phenotypes do not seem to play a role in Toxoplasma gondii infection in cats. These findings contribute to our knowledge of the role of blood types in disease susceptibility in cats. Full article

Flavivirus infections, including dengue, Zika, West Nile, and Japanese encephalitis, remain a major global health concern. Although several vaccines are licensed, the durability and qualitative features of vaccine-induced antibodies differ substantially across platforms, leading to incomplete cross-protection and the risk of antibody-dependent enhancement. Long-term durability is exemplified by YF-17D, which induces protective antibodies that have been detectable for decades, whereas the JE SA14-14-2 vaccine has achieved program-level reductions in disease in endemic regions. In contrast, CYD-TDV shows serostatus-dependent outcomes, and the investigational TAK-003 vaccine has demonstrated antibody persistence for at least four years. Recent studies have clarified how preserving quaternary envelope epitopes, minimizing prM-associated non-neutralizing specificity, and sustaining germinal center activity determine antibody affinity, breadth, and persistence. Advances in adjuvant formulations and delivery platforms have shown that engaging defined innate pathways and prolonging antigen availability enhance affinity maturation and long-lived plasma cell formation. Booster scheduling and baseline serostatus further shape the antibody quality, highlighting the importance of immune imprinting and cross-reactivity in vaccine design. Together, these findings outline the design principles for next-generation flavivirus vaccines, including stabilization of neutralization-sensitive epitopes, use of adjuvants that sustain germinal center responses, optimization of antigen persistence, and tailoring of dosing strategies to immune history to elicit durable and broadly protective humoral immunity. Full article

The emergence of drug-resistant cytomegalovirus (CMV) complicates viral response to therapy. We present two cases of solid organ transplant (SOT) recipients, highlighting the reversion of UL97 mutations associated with val(ganciclovir) resistance. Patient 1, a heart transplant recipient, initially received pre-emptive treatment with val(ganciclovir), followed by foscarnet for recurrent CMV episodes. Mutations A594V in the UL97-kinase gene and V715M in the UL54-polymerase gene were detected. He developed CMV colitis and was then treated with maribavir. After discontinuing val(ganciclovir), genotyping revealed no resistance mutations. Following CMV DNA suppression, secondary prophylaxis with letermovir and val(ganciclovir) was initiated. Patient 2, a double-lung transplant recipient, experienced several CMV episodes. Initially treated with val(ganciclovir), he developed the L595S mutation in the UL97 kinase gene, conferring resistance. Therapy was then switched to foscarnet, which was suspended due to renal failure, and then to maribavir. Subsequently, the H411Y mutation in the UL97 was detected, conferring maribavir resistance, while val(ganciclovir) mutation was no longer detectable. He was then treated with val(ganciclovir) and letermovir, achieving undetectable CMV DNA, and then continued letermovir alone as prophylaxis. Detecting gene mutations that confer drug resistance is crucial for managing antiviral therapy when virological response is lacking. In our cases, the reversion of (va)ganciclovir-resistance mutations occurred after drug withdrawal, a previously unreported finding. Full article

Background: While host immune responses to SARS-CoV-2 vaccination are routinely assessed through IgG measurements, less is known about the temporal dynamics of vaccine-induced cellular immunity, particularly in individuals who fail to develop detectable IgG antibodies after COVID-19 vaccination. Objective: To investigate the development and timing of T-cell immunity following SARS-CoV-2 vaccination in antibody-non-responders to COVID-19 vaccination. Methods: A cross-sectional analysis was conducted on COVID-19-naive individuals who had received full SARS-CoV-2 vaccination, categorized by SARS-CoV-2 IgG serostatus. T-cell response was evaluated using the IGRA methodology T-SPOT^®.COVID (Oxford Immunotec, Abingdon, Oxfordshire, UK). T-cell response rates and levels were compared between SARS-CoV-2 seropositive and seronegative groups, and a temporal cutoff analysis was applied to examine trends in T-cell response over time. Results: Within the seronegative group, IgG levels showed a strong negative correlation with time since vaccination (Spearman ρ = −0.65, p < 0.001), while T-cell response levels exhibited a weak positive time-dependent trend (ρ = 0.15, p = 0.019). Temporal cutoff analysis identified a critical time-point beginning at 80 days post-vaccination, after which both T-cell response rates and levels were significantly higher. Specifically, individuals tested after 80 days showed increased median T-cell response levels (U = 4205, p < 0.001) and higher positive T-cell response rate (67% vs. 38%, Χ² = 17.06, p < 0.001). Conclusions: Cellular immunity response against SARS-CoV-2 may emerge later than expected in antibody-non-responders to COVID-19 vaccination, with the 80-day post-vaccination mark emerging as a critical time point. Our results support the inclusion of cellular assays in post-vaccination monitoring and emphasize the need to reconsider the timing and criteria for evaluating vaccine response. Full article

Background: Cryptococcosis, a systemic mycosis, remains a neglected disease in Brazil due to the absence of systematic national surveillance. This study developed an interactive dashboard to analyze cryptococcosis-related deaths (2000–2022) and forecast trends through regional ARIMA modeling. Methodology: The Cross-Industry Standard Process for Data Mining framework was employed to extract mortality data from the Brazilian Mortality Information System, utilizing the microdatasus package in R Studio software, with R version 3.4.0. The records were then filtered using the International Classification of Diseases, Tenth Revision codes (B45 series) to identify primary and associated causes of death. After data extraction, a series of data preprocessing steps was implemented, including deduplication, variable recoding, and the management of missing values. The Shiny framework was employed to construct an interactive dashboard, incorporating Plotly and DT packages, with time-series visualizations, demographic variables, and multilingual support (Portuguese/English). Results: Among 12,308 deaths (2227 primary; 10,081 associated causes), most occurred in males aged 21–60 years. Data completeness was high for age/residence (100%) but lower for education (82%). The dashboard enables dynamic exploration of trends, demographic patterns, and open-data downloads. Regional ARIMA models revealed heterogeneous forecasts, with the Southeast projecting a decline (193 deaths in 2025; 95% CI: 146–240) and the South showing stability (141 deaths; 95% CI: 109–173). Conclusions: This tool bridges a critical gap in cryptococcosis surveillance, enabling dynamic mortality trend analysis, identification of high-risk demographics, and regional forecasting to guide public health resource allocation. While the absence of HIV serostatus data limits etiological analysis, the dashboard’s open-source framework supports adaptation for other neglected diseases. Full article

Background: Cytomegalovirus (CMV) remains a formidable complication in small bowel transplantation (SBT) due to the graft’s high immunogenicity and profound immunosuppression required, with refractory disease representing a particularly devastating challenge. Case: We report an 18-year-old male who underwent SBT, complicated by recurrent acute rejection episodes requiring intensive immunosuppression. He developed refractory CMV disease, marked by non-response to first line therapy with ganciclovir—despite the absence of genotypic resistance—necessitating sequential use of foscarnet, dual antivirals, CMV immunoglobulin, and novel agents (maribavir and letermovir). Discussion: This case illustrates the multifactorial drivers of refractory CMV disease in SBT recipients, including donor–recipient serostatus mismatch, profound immunosuppression through T-cell-depleting induction, corticosteroid exposure, and biologic therapy. It highlights the distinction between refractory and resistant CMV, and the role of combination antiviral strategies including novel agents to achieve disease control. Outcomes remain dismal despite aggressive and innovative therapies, underscoring the limited efficacy of interventions in the context of severe immunologic compromise. Conclusions: Refractory CMV enteritis in SBT exemplifies the extreme difficulty of balancing viral control with rejection management. Despite exhausting antiviral strategies, survival remains poor. Highlights: Refractory CMV enteritis is a significant challenge in small bowel transplant recipients due to intense immunosuppression. Persistent CMV disease may occur despite antiviral prophylaxis and the absence of resistant gene mutations. Combination antiviral strategies, including maribavir, demonstrated significant clinical improvement. Profound immunosuppression required to manage acute graft rejection episodes complicates antiviral management and disease clearance. Despite best efforts in CMV management in this population, outcomes may still be compromised by unrelated or compounding factors. Full article

T cell receptor (TCR) profiling using next-generation sequencing (NGS) enables high-throughput, in-depth analysis of repertoire diversity, offering numerous clinical applications. We developed a DNA-based strategy to analyse the TCRβ-chain using NGS and established reference values for T cell repertoire characteristics in 74 healthy donors, including 44 adults, 20 paediatrics, and 10 cord blood units (CBUs). Additionally, four paediatric patients with combined immunodeficiency (CID) or severe CID (SCID) due to deleterious mutations in recombination activating genes (RAG) were analysed. The developed strategy demonstrated high specificity, reproducibility, and sensitivity, and all functional variable and joining genes were detected with minimal PCR bias. All donors had a Gaussian-like distribution of complementary-determining region 3 length, with lower presence of non-templated nucleotides and higher proportion of non-functional clonotypes in CBUs. Both CBUs and paediatrics showed greater convergence and TCRβ diversity was significantly lower in adults and donors with cytomegalovirus-positive serostatus. Finally, an analysis of paediatric patients with RAG-SCID/CID showed significantly shorter CDR3 region length and lower repertoire diversity compared to healthy paediatrics. In summary, we developed a reliable and feasible TCRβ sequencing strategy for application in the clinical setting, and established reference values that could assist in the diagnosis and monitoring of pathological conditions affecting the T cell repertoire. Full article

Background: The hepatitis A virus (HAV) is a major cause of acute viral hepatitis and a significant global health concern. This study provides a pre-vaccination baseline for Oman, enabling longitudinal comparison with post-hepatitis A vaccination cohorts. This study aimed to determine the pre-vaccination seroprevalence of HAV antibodies (anti-HAV) in Oman and explore the associated demographic factors. Methods: A cross-sectional study was conducted from April 2014 to August 2015 among patients attending the medical outpatient clinic of the Medical City Hospital for Military and Security Services. Demographic data were collected via a structured questionnaire, and serum samples were tested for anti-HAV immunoglobulin IgG and IgM using enzyme-linked immunosorbent assays. Multivariate analysis was performed to identify the predictors of anti-HAV seroprevalence. Results: Among 1975 participants, 88.1% were positive for anti-HAV IgG. The mean age was 37.4 ± 16.1 years; however, those negative for anti-HAV IgG were considerably younger (mean age: 24.8 ± 15.7 years). Anti-HAV IgG seroprevalence was 37% in individuals aged ≤18 years and 91% in those >18 years (p < 0.001). The factors associated with seropositivity included older age (p < 0.001), consuming food prepared outside the home (p < 0.001), occupation (p < 0.001), and education level (p = 0.003). In the multivariable analysis, only age showed a strong independent association with serostatus: per 10-year increase, the aOR for anti-HAV IgG seropositivity was 2.87 (95% CI 2.25–3.63; p < 0.001). Conclusions: Our study estimates show high anti-HAV IgG seroprevalence and serve as a pre-vaccination baseline for evaluating the hepatitis A vaccination program in Oman over time. Given the lower natural exposure among younger cohorts, continued routine vaccination, scheduled serosurveys, and strengthened surveillance are required to identify emerging immunity gaps and prevent future HAV outbreaks. Full article

Cytomegalovirus (CMV) is the leading infectious cause of birth defects and has been linked to increased risk of preterm birth (PTB). CMV establishes lifelong latency and is more prevalent among Black and Hispanic/Latina women, populations already at higher risk for adverse pregnancy outcomes. Vitamin D deficiency, also common in these groups, has been linked to impaired immune function and increased susceptibility to infections, including CMV. In this cross–sectional study of 63 pregnant minority women (50 CMV+, 13 CMV−), we evaluated associations among serum 25(OH)D levels, CMV serostatus, and cmvIL–10, the CMV–encoded interleukin–10 homolog that modulates host immune responses. While vitamin D insufficiency and CMV seropositivity were both highly prevalent, we found no statistically significant associations between 25(OH)D levels and CMV serostatus or cmvIL–10 levels. These findings highlight the need for further investigation into how vitamin D deficiency and CMV infection may independently or synergistically contribute to maternal and neonatal health disparities. Full article

Vaccination is highly effective in preventing human papillomavirus (HPV) infection, but traditional pseudovirion-based neutralization assays (PBNA) are technically demanding, labor-intensive, and costly, limiting their use in multivalent vaccine studies. We developed and validated an automated, high-throughput PBNA in a 384-well format that quantifies neutralizing antibodies against 15 HPV types using triple-color pseudotyped viruses. Non-interfering type triplets were defined from cross-neutralization assays of serum against pseudotyped viruses, enabling simultaneous detection of three fluorescence signals per well. The workflow integrates a cap-decapper, semi-automatic sample addition and dilution, and a microplate stacker with automated imaging to reduce hands-on time. The 384-well method showed strong concordance with the conventional 96-well PBNA while increasing daily sample throughput by approximately 6.7-fold, reducing assay duration (including ~4-fold faster imaging), and lowering reaction volume by ~5-fold. Analytical validation demonstrated acceptable specificity, accuracy, repeatability, linearity and robustness for high-throughput use. Serostatus cutoff values were established in an age-appropriate female population to support classification of positive versus negative sera. This platform provides a scalable tool for evaluating neutralizing antibodies after natural infections or vaccination and is well suited for large clinical trials and the development of next-generation and multivalent HPV vaccines. Full article

Blood transfusion remains vital in healthcare but poses risks, particularly from transfusion-transmissible viral infections (TTVIs). This study aims to determine the seroprevalence of HIV, HBV, and HCV among blood donors in Borgou (Benin) in 2023. This prospective, cross-sectional study involved voluntary, non-remunerated blood donors recruited via mobile campaigns and at a fixed site from January to December 2023. Screening for HIV, HBV, and HCV was performed using fourth-generation ELISA (Biorad^®). Data analysis used SPSS with Chi-square test of independence (p < 0.05), and multiple logistic regression identified independent risk factors. Among 9646 donors, 87.80% were male (sex ratio 7.19), mostly aged 18–24 (55.93%), with students forming the largest group (58.67%). Mobile units collected 70.80% of donations; 52.60% were repeat donors. Overall TTVI seroprevalence was 9.35%, with HBV (6.29%) most common, followed by HCV (1.78%) and HIV (1.28%). Chi-square tests revealed significant associations between serostatus and donor status, donation site, and occupation, but not sex. Logistic regression identified independent risk factors: age, donor status, and donation site were significantly associated with HIV infection; male sex, older age, occupation, and donor status predicted HBV infection; and only donor status was significantly associated with HCV infection. These findings highlight the need for targeted recruitment and awareness strategies to improve transfusion safety. Full article

Background: Annual influenza vaccine updates target viral drift, but immune responses may be biased by original antigenic sin (OAS). Few studies have explored this across closely related strains. This study examines how OAS shapes responses to sequential influenza variants in the context of seasonal vaccination. Methods: We conducted a prospective, longitudinal study to assess the humoral immune response to the 2023–2024 seasonal influenza vaccine containing the A/Victoria/4897/2022 (H1N1) strain. Bioinformatic analyses compared the hemagglutinin (HA) sequences of A/Victoria/4897/2022 and the antigenically related A/Victoria/2570/2019 strain. B-cell epitopes were mapped with BepiPred-3.0 and BepiBlast, and their physicochemical properties analyzed via accessibility, β-turns, flexibility, and hydrophilicity. Antibody responses were measured pre- and 28 days post-Vaxigrip Tetra vaccination in young (18–35) and older (>65) adults, stratified by cytomegalovirus (CMV) serostatus. HA sequences showed >97% identity, with variations mainly in the globular head. Predicted B-cell epitopes overlapped variable sites, suggesting possible immune escape. Despite having been vaccinated against the 2022 strain, serology showed higher antibody titers against the 2019 HA strain in all participants. This pattern suggests a potential antigen imprinting effect, though confirmation awaits further analysis. Age groups differed: older adults showed greater variability, while younger CMV+ individuals tended toward stronger 2019 HA responses. Conclusions: These findings suggest a complex interplay of factors shaping immune responses, though the imprinting effect and the potential role of CMV warrant further exploration in larger, more focused studies. Full article