Immunity In Recipients Research Articles

Cytomegalovirus immunity in high-risk liver transplant recipients following preemptive antiviral therapy versus prophylaxis.

CMV-specific T cells, NK cells, and neutralizing antibodies (nAbs) were assessed in a randomized trial of CMV prevention with preemptive antiviral therapy (PET) versus prophylactic antiviral therapy (PRO) in donor-seropositive/recipient-seronegative (D+R-) liver transplant recipients (LTxR) at 100 days (end of intervention) and at 6 and 12 months after transplant. The PET group had significantly increased numbers of circulating polyfunctional T cells, NK cells, and nAbs compared with the PRO group at day 100, and several CMV immune parameters remained significantly higher by 12 months after transplant. Among PET recipients, preceding CMV viremia (vs. no preceding viremia) was associated with significantly higher levels of most CMV immune parameters at day 100. Higher numbers of CMV-specific polyfunctional T cells and NKG2C+ NK cells at day 100 were associated with a decreased incidence of CMV disease in multivariable Cox regression. The strongest associations with protection against CMV disease were with increased numbers of CMV-specific polyfunctional CD4+ T cells, CD3negCD56dimCD57negNKG2Cpos cells, and CD3negCD56dimCD57posNKG2Cpos NK cells. Our results suggest that PET is superior to PRO for CMV disease prevention by allowing low-level CMV replication and associated antigen exposure that is promptly controlled by antiviral therapy and facilitates enhanced CMV protective immunity in D+R- LTxR.

410.6: Perioperative immunoabsorption in immunized kidney transplant recipients leads to higher graft survival rates.

410.6: Perioperative immunoabsorption in immunized kidney transplant recipients leads to higher graft survival rates.

The Aryl Hydrocarbon Receptor Controls IFNγ-Induced Immune Checkpoints PD-L1 and IDO via the JAK/STAT Pathway in Lung Adenocarcinoma.

While immunotherapy has shown efficacy in lung adenocarcinoma (LUAD) patients, many respond only partially or not at all. One limitation in improving outcomes is the lack of a complete understanding of immune checkpoint regulation. Here, we investigated a possible link between an environmental chemical receptor implicated in lung cancer and immune regulation, (the aryl hydrocarbon receptor/AhR), a known but counterintuitive mediator of immunosuppression (IFNγ), and regulation of two immune checkpoints (PD-L1 and IDO). AhR gene-edited LUAD cell lines, a syngeneic LUAD mouse model, bulk- and scRNA sequencing of LUADs and tumor-infiltrating leukocytes were used to map out a signaling pathway leading from IFNγ through the AhR to JAK/STAT, PD-L1, IDO, and tumor-mediated immunosuppression. The data demonstrate that: 1) IFNγ activation of the JAK/STAT pathway leading to PD-L1 and IDO1 upregulation is mediated by the AhR in murine and human LUAD cells, 2) AhR-driven IDO1 induction results in the production of Kynurenine (Kyn), an AhR ligand, which likely mediates an AhR→IDO1→Kyn→AhR amplification loop, 3) transplantation of AhR-knockout LUAD cells results in long-term tumor immunity in most recipients. 4) The 23% of AhR-knockout tumors that do grow do so at a much slower pace than controls and exhibit higher densities of CD8+ T cells expressing markers of immunocompetence, increased activity, and increased cell-cell communication. The data definitively link the AhR to IFNγ-induced JAK/STAT pathway and immune checkpoint-mediated immunosuppression and support the targeting of the AhR in the context of LUAD.

Persistent defect in SARS-CoV-2 humoral and cellular immunity in lung transplant recipients

Lung transplant recipients (LTRs) are susceptible to severe Coronavirus Disease 2019 (COVID-19) and had lower immune responses to primary severe acute respiratory syndrome-related to coronavirus 2 (SARS-CoV-2) vaccination as compared to the general population and to other solid organ transplant recipients. As immunity induced by booster vaccination and natural infection has increased since the beginning of the pandemic in the general population, immunity acquired by LTRs is not well documented. Humoral and cellular immunity to SARS-CoV-2 was monitored in February and May 2023 in 30 LTRs and compared to that of health care workers (HCWs) and nursing home residents (NHRs). LTRs had significantly lower levels of SARS-CoV-2 binding and neutralizing antibodies and lower interferon-gamma responses to Wuhan, Delta, and XBB1.5 variants as compared to HCWs and NHRs. Humoral immunity decreased between the 2 visits,whereas cellular immunity remained more stable. The persistent defect in SARS-CoV-2 immunity in LTRs should encourage continued monitoring and preventive measures for this vulnerable population.

Association between the lung microbiome and perioperative prognosis in lung transplant recipients.

Studies have confirmed that the lung microbiome of lung transplant recipients is altered and serves as a prognostic indicator for long-term mortality. Other studies reported that the lung microbiome affects host immunity and the transcriptome. However, the lung microbiome composition at the early post-transplant period following lung transplantation is unclear, and the relationship of the lung microbiome with pulmonary immunity and the host transcriptome is also not well understood. We hypothesize that changes in the lung microbiome composition in the early post-transplant period may have a predictive value for perioperative outcomes following lung transplantation and that the lung microbiome is correlated with pulmonary immunity and the host transcriptome. Thus, this prospective study aimed at observing the lung microbiome composition in the early post-transplant period and the impact of the lung microbiome on pulmonary cytokines and the host transcriptome. Our findings will help us gain a comprehensive understanding of the distribution and significance of the lung microbiome in the early post-transplant period. An observational study was conducted to identify the lung microbiome and the host transcriptome characteristics using next-generation sequencing. Luminex was employed for quantifying alveolar cytokines. Spearman's correlation analysis was utilized to assess the impact of the lung microbiome on pulmonary immunity and differentially expressed genes in patients who died perioperatively after lung transplantation. Patients with poor perioperative outcomes showed an increase in Mycoplasma and Arcobacter, a decrease of Gemella, and increased interleukin (IL)-10, IL-1β, and tumor necrosis factor (TNF)-α concentration. The lung microbiome correlates with lung immunity in lung transplant recipients. In the death group, the function of differentially expressed genes is associated with cell apoptosis, and promoting TNF production is upregulated. The lung microbiome is related to differentially expressed genes between the two groups. The lung microbiome and cytokines can be considered as potential biomarkers for early prognosis in lung transplant recipients. The lung microbiome is associated with both lung immunity and differentially expressed genes in lung transplant recipients.

SARS-CoV-2 Omicron infection augments the magnitude and durability of systemic and mucosal immunity in triple-dose CoronaVac recipients.

There is a paucity of data indicating the durability of the immune response and the impact of immune imprinting induced by CoronaVac upon Omicron breakthrough infection. In this prospective cohort study, the anti-severe acute respiratory syndrome coronavirus 2 adaptive responses were analyzed before and after the Omicron BA.5 infection. Our data provide detailed insight into the protective role of the inactivated COVID-19 vaccine in shaping humoral and cellular immune responses to heterologous Omicron infection. This study is registered with ClinicalTrials.gov as NCT05680896.

Diminished measles immunity after paediatric liver transplantation-A retrospective, single-centre, cross-sectional analysis.

Liver transplantation in childhood has an excellent long-term outcome, but is associated with a long-term risk of infection. Measles is a vaccine-preventable infection, with case series describing severe courses with graft rejection, mechanical ventilation and even death in liver transplant recipients. Since about 30% of liver transplanted children receive liver transplants in their first year of life, not all have reached the recommended age for live vaccinations. On the contrary, live vaccines are contraindicated after transplantation. In addition, vaccination response is poorer in individuals with liver disease compared to healthy children. This retrospective, single-centre, cross-sectional study examines measles immunity in paediatric liver transplant recipients before and after transplantation. Vaccination records of 239 patients, followed up at Hannover Medical School between January 2021 and December 2022 were analysed. Twenty eight children were excluded due to stem cell transplantation, regular immunoglobulin substitution or measles vaccination after transplantation. More than 55% of all 211 children analysed and 75% of all those vaccinated at least once are measles seropositive after transplantation-48% after one and 84% after two vaccinations-which is less than in healthy individuals. Interestingly, 26% of unvaccinated children also showed measles antibodies and about 5-15% of vaccinated patients who were seronegative at the time of transplantation were seropositive afterwards, both possibly through infection. In multivariable Cox proportional hazards regression, the number of vaccinations (HR 4.30 [95% CI 2.09-8.83], p<0.001), seropositivity before transplantation (HR 2.38 [95% CI 1.07-5.30], p = 0.034) and higher age at time of first vaccination (HR 11.5 [95% CI 6.92-19.1], p<0.001) are independently associated with measles immunity after transplantation. In contrast, older age at testing is inversely associated (HR 0.09 [95% CI 0.06-0.15], p<0.001), indicating a loss of immunity. Vaccination in the first year of life does not pose a risk of non-immunity. The underlying liver disease influences the level of measles titres of twice-vaccinated patients; those with acute liver failure being the lowest compared to children with metabolic disease. In summary, vaccine response is poorer in children with liver disease. Liver transplant candidates should be vaccinated before transplantation even if this is earlier in the first year of life. Checking measles IgG and re-vaccinating seronegative patients may help to achieve immunity after transplantation.

A novel immunofluorescent test system for SARS-CoV-2 detection in infected cells.

Highly variable pandemic coronavirus SARS-CoV-2, which causes the hazardous COVID-19 infection, has been persistent in the human population since late 2019. A prompt assessment of individual and herd immunity against the infection can be accomplished by using rapid tests to determine antiviral antibody levels. The microneutralization assay (MN) is one of the most widely used diagnostic methods that has been proposed to assess the qualitative and quantitative characteristics of virus-specific humoral immunity in COVID-19 convalescents or vaccine recipients. However, some aspects of the assay, such as sensitivity and time cost, need improvement. Here, we developed an express test, which may be potentially used in clinical practice for the assessment of serum-caused SARS-CoV-2 inhibition in infected cell cultures. It implies the detection and counting of coronaviral fluorescent-forming units (FFU) and includes two sequentially used developing components: biotinylated mouse monoclonal antibodies against the recombinant N protein of SARS-CoV-2 (B.1) and the recombinant EGFP-streptavidin fusion protein. Due to the universal specificity of the antibodies, our analytical tool is suitable for the detection of various strains of SARS-CoV-2 when determining both the infectious titer of viruses and the titer of serum virus-neutralizing antibodies. The developed two-component test system is characterized by high sensitivity, a reduced number of analytic stages and low assay cost, as well as by flexibility, since it may be modified for detection of other pathogens using the appropriate antibodies.

A strategy to reconstitute immunity without GVHD via adoptive allogeneic Tscm therapy.

Adoption of allogeneic T cells directly supplements the number of T cells and rapidly induces T-cell immunity, which has good efficacy for treating some tumors and immunodeficiency diseases. However, poor adoptive T-cell engraftment and graft-versus-host disease (GVHD) limit the application of these methods. Alloreactive T-cell clones were eliminated from the donor T-cell repertoire, and the remaining T-cell clones were prepared as Tscm for T-cell adoptive treatment to reconstruct recipient T-cell immunity without GVHD. The subjects in this study included three different strains of mice. Lymphocytes from mice (C57BL/6) were used as the donor T-cell repertoire, from which the Tscm allo-reactive T cell clone was depleted (ATD-Tscm). This was confirmed by showing that the Tscm was not responsive to the alloantigen of the recipient (BALB/c). To prepare ATD-Tscm cells, we used recipient lymphocytes as a simulator, and coculture of mouse and recipient lymphocytes was carried out for 7 days. Sorting of non-proliferative cells ensured that the prepared Tscm cells were nonresponsive. The sorted lymphocytes underwent further expansion by treatment with TWS119 and cytokines for an additional 10 days, after which the number of ATD-Tscm cells increased. The prepared Tscm cells were transferred into recipient mice to observe immune reconstitution and GVHD incidence. Our protocol began with the use of 1×107 donor lymphocytes and resulted in 1 ×107 ATD-Tscm cells after 17 days of preparation. The prepared ATD-Tscm cells exhibited a nonresponse upon restimulation of the recipient lymphocytes. Importantly, the prepared ATD-Tscm cells were able to bind long and reconstitute other T-cell subsets in vivo, effectively recognizing and answering the "foreign" antigen without causing GVHD after they were transferred into the recipients. Our strategy was succeeded to prepare ATD-Tscm cells from the donor T-cell repertoire. The prepared ATD-Tscm cells were able to reconstitute the immune system and prevent GVHD after transferred to the recipients. This study provides a good reference for generating ATD-Tscm for T-cell adoptive immunotherapy.

Integrated Immunization Information System in Indonesia: Prototype Design Using Quantitative and Qualitative Data.

As the volume of immunization records increases, problems with fragmented records arise, especially since the majority of records in developing countries, including Indonesia, remain paper based. Implementing an immunization information system (IIS) offers a solution to this problem. In this study, we designed an integrated IIS prototype in Indonesia using the design science research (DSR) methodology. The stages of the DSR methodology followed in this study included identifying problems and motivating and defining objectives for a solution, design and development, demonstration, evaluation, communication, and drawing conclusions and suggestions. Specifically, this study began with problem formulation and a literature review. We then applied quantitative (questionnaire with 305 members of the public) and qualitative (interviews with 15 health workers including nurses, midwives, and doctors) data collection approaches. The resulting high-fidelity prototype follows the 8 golden rules. There are 2 IIS designs, one for the public as immunization recipients and another for health workers. The functionalities include immunization history, schedule, recommendations, verification, certificates, reminders and recalls, coverage, monitoring, news, and reports of adverse events. Evaluation of the prototype was carried out through interviews and a questionnaire designed according to the System Usability Scale (SUS) and Post-Study System Usability Questionnaire (PSSUQ). The SUS value was 72.5 or "Good (Acceptable)," while the system usefulness, information quality, interface quality, and overall value on the PSSUQ were 2.65, 2.94, 2.48, and 2.71, respectively, which indicate it has an effective design. This provides a guide for health facilities, health regulators, and health application developers on how to implement an integrated IIS in Indonesia.

Assessing vaccine-induced immunity against pneumococcus, hepatitis A and B over a 9-year follow-up in pediatric liver transplant recipients: A nationwide retrospective study

Pediatric liver transplant recipients are particularly at risk of infections. The most cost-effective way to prevent infectious complications is through vaccination, which can potentially prevent infections due to hepatitis B (HBV) virus, hepatitis A virus (HAV), and invasive pneumococcal diseases. Here, we performed a retrospective analysis of HBV, HAV, and pneumococcal immunity in pediatric liver transplant recipients between January 1, 2009, and December 31, 2020, to collect data on immunization and vaccine serology. A total of 94% (58/62) patients had available vaccination records. At transplant, 90% (45/50) were seroprotected against HBV, 63% (19/30) against HAV, and 78% (18/23) had pneumococcal immunity, but immunity against these 3 pathogens remained suboptimal during the 9-year follow-up. A booster vaccine was administered to only 20% to 40% of patients. Children who had received >4 doses of HBV vaccine and > 2 doses of HAV vaccine pretransplant displayed a higher overall seroprotection over time post-solid organ transplant. Our findings suggest that a serology-based approach should be accompanied by a more systematic follow-up of vaccination, with special attention paid to patients with an incomplete vaccination status at time of transplant.

Respiratory torque teno virus load at emergency department visit predicts intensive care unit admission of SARS-CoV-2 infected patients.

Accurate prediction of COVID-19 severity remains a challenge. Torque teno virus (TTV), recognized as a surrogate marker of functional immunity in solid organ transplant recipients, holds the potential for assessing infection outcomes. We investigated whether quantifying TTV in nasopharyngeal samples upon emergency department(ED) admission could serve as an early predictor of COVID-19 severity. Retrospective single-center study in the ED of Saint-Louis Hospital in Paris, France. TTV DNA was quantified in nasopharyngeal swab samples collected for SARS-CoV-2 testing. Among 295 SARS-CoV-2 infected patients, 92 returned home, 160 were admitted to medical wards, and 43 to the intensive care unit (ICU). Elevated TTV loads were observed in ICU patients (median: 3.02 log copies/mL, interquartile range [IQR]: 2.215-3.825), exceeding those in discharged (2.215, [0; 2.962]) or hospitalized patients (2.24, [0; 3.29]) (p = 0.006). Multivariate analysis identified diabetes, obesity, hepatitis, fever, dyspnea, oxygen requirement, and TTV load as predictors of ICU admission. A 2.91 log10 copies/mL TTV threshold independently predicted ICU admission. Nasopharyngeal TTV quantification in SARS-CoV-2 infected patients is linked to the likelihood of ICU admission and might reflect respiratory immunosuppression.

863. ELISpot-BK virus assay for the assesment of BK virus cell-mediated immunity in kidney recipients

Abstract Background The pre and post-transplant monitoring of BKV-specific T cells could be a useful marker to identify renal receptors at risk of BKV reactivation and consequently develop BKV nephropathy. Methods We performed a prospective multicenter study between October 2020 and December 2021. BKV-ELISPOT was performed before and two months after kidney transplantation in included patients. Other variables such as demographic, immunosuppressive therapy, presence of biopsy-proven rejection, lymphopenia, CD4 count levels and development of BK infection and nephropathy were prospectively recorded. Results We included 66 patients during the study period of whom median age was 56 (SD 16) and 60% were men. Twenty-nine percent of them received a prior transplantation, 17% was a living donor and 74% needed haemodialysis prior transplantation. Ninety-two percent received induction therapy and 86% maintenance therapy was with 3 drugs. Fifty-one percent of patients presented lymphopenia at 2 months post transplantation with a median CD4 count levels of 298 (IQR 176-899). Prior transplantation 30% of patients presented a reactive ELISPOT-BKV test, whereas at 2 months post transplantation only 21% of them tested positive. Five patients presented a BK infection and 2 of them a BK nephropathy, all of them presenting with impaired graft function at one year post transplantation.Twenty-eight percent of them presented a biopsy-proven acute rejection. All patients that presented a BKV infection presented a non-reactive ELISPOT-BKV test prior transplantation and at 2 months post transplantation. After performing multivariate analysis, neither lymphopenia, acute allograft rejection nor ELISPOT-BKV test were related to BKV infection, probably due to low incidence of BKV infection in this subgroup of kidney recipients. Conclusion BKV-ELISPOT test could be a valuable tool to predict BKV infection or nephropathy and could be useful to implement preventive measures such pre-emptive reduction of immunosuppressive therapy in kidney recipients. Disclosures All Authors: No reported disclosures

Impact of a booster dose on SARS-CoV2 mRNA vaccine-specific humoral-, B- and T cell immunity in pediatric stem cell transplant recipients

Stem cell transplant recipients (SCTR) are imperiled to increased risks after SARS-CoV2 infection, supporting the need for effective vaccination strategies for this vulnerable group. With respect to pediatric patients, data on immunogenicity of SARS-CoV2 mRNA-based vaccination is limited. We therefore comprehensively examined specific humoral, B- and T cell responses in a cohort of 2-19 year old SCTR after the second and third vaccine dose. Only after booster vaccination, transplant recipients reached similar levels of vaccine-specific IgG, IgA and neutralizing antibodies against omicron variant as age-matched controls. Although frequencies of SARS-CoV2 specific B cells increased after the third dose, they were still fourfold reduced in patients compared to controls. Overall, the majority of individuals enrolled mounted SARS-CoV2 Spike protein-specific CD4+ T helper cell responses with patients showing significantly higher portions than controls after the third dose. With respect to functionality, however, SCTR were characterized by reduced frequencies of specific interferon gamma producing CD4+ T cells, along with an increase in IL-2 producers. In summary, our data identify distinct quantitative and qualitative impairments within the SARS-CoV2 vaccination specific B- and CD4+ T cell compartments. More importantly, humoral analyses highlight the need for a booster vaccination of SCTR particularly for development of neutralizing antibodies.

Hybrid and SARS-CoV-2-vaccine immunity in kidney transplant recipients

Kidney transplant recipients (KTR) are at high risk for severe COVID-19 and have demonstrated poor response to vaccination, making it unclear whether successive vaccinations offer immunity and protection. We conducted a serologically guided interventional study where KTR patients that failed to seroconvert were revaccinated and also monitored seroconversion of KTR following the Norwegian vaccination program. We analysed IgG anti-RBD Spike responses from dose 2 (n=432) up to after the 6th (n=37) mRNA vaccine dose. The frequency and phenotype of Spike-specific T and B cell responses were assessed in the interventional cohort after 3-4 vaccine doses (n=30). Additionally, we evaluated the Specific T and B cell response to breakthrough infection (n=32), measured inflammatory cytokines and broadly cross-neutralizing antibodies, and defined the incidence of COVID-19-related hospitalizations and deaths. The Norwegian KTR cohort has a male dominance (2323 males, 1297 females), PBMC were collected from 114 male and 78 female donors. After vaccine dose 3, most KTR developed Spike-specific T cell responses but had significantly reduced Spike-binding B cells and few memory cells. The B cell response included a cross-reactive subset that could bind Omicron VOC, which expanded after breakthrough infection (BTI) and gave rise to a memory IgG+B cell response. After BTI, KTR had increased Spike-specific T cells, emergent non-Spike T and B cell responses, and a systemic inflammatory signature. Late seroconversion occurred after doses 5-6, but 38% (14/37) of KTR had no detectable immunity even after multiple vaccine doses. Boosting vaccination can induce Spike-specific immunity that may expand in breakthrough infections highlighting the benefit of vaccination to protect this vulnerable population. CEPI and internal funds.

Human herpesvirus 6-specific T-cell immunity in allogeneic hematopoietic stem cell transplant recipients.

Human herpesvirus 6 (HHV-6) can reactivate after allogeneic hematopoietic stem cell transplant (allo-HSCT) and may lead to severe symptoms. HHV-6-specific immune responses after HSCT are largely unexplored. We conducted a prospective observational study on 208 consecutive adult patients who received allo-HSCT to investigate HHV-6 reactivations and specific immune responses. Interferon gamma-producing HHV-6-specific T cells were quantified using enzyme-linked immunospot assay (ELISpot). HHV-6 reactivation occurred in 63% of patients, at a median of 25 days from allo-HSCT. Only 40% of these presented a clinically relevant infection, defined by the presence of classical HHV-6 end-organ diseases (EODs), based on European Conference on Infections in Leukaemia (ECIL) guidelines, and other possible HHV6-related EODs. Using multivariate analysis, we identified risk factors for HHV-6 reactivation: previous allo-HSCT, posttransplant cyclophosphamide (PT-Cy), and time-dependent steroids introduction. The use of PT-Cy and steroids were associated with clinically relevant infections, whereas higher CD3+ cell counts seemed to be protective. Interestingly, circulating HHV-6-specific T cells were significantly higher in patients with reactivated virus. Moreover, HHV-6-specific T-cell responses, quantified at >4 days after the first viremia detection, predicted clinically relevant infections (P< .0001), with higher specificity (93%) and sensitivity (79%) than polyclonal CD3+ cells per μL. Overall survival and transplant-related mortality were not affected by time-dependent HHV-6 reactivation, whereas a significant association was observed between clinically relevant infections and acute graft-versus-host disease. These results shed light on the role of HHV-6 in allo-HSCT and may affect HHV-6 monitoring and treatment.

Platelet extracellular vesicles and their mitochondrial content improve the mitochondrial bioenergetics of cellular immune recipients.

Mitochondria play a critical role in the production of cell energy and the regulation of cell death. Therefore, mitochondria orchestrate numerous cell effector functions, including fine-tuning the immune system. While mitochondria are mainly found intracellularly, they can escape the confine of the cell during the process of extracellular vesicle release. Platelets patrol blood vessels to ensure vasculature integrity and to support the immune system. In blood, platelets are the primary source of circulating mitochondria. Activated platelets produce extracellular vesicles, including a subset of mitochondria-containing vesicles. We characterized mitochondrial functions in platelet-derived extracellular vesicles, and examined whether they could impact the bioenergetics of cellular immune recipients using an extracellular flux analyzer to measure real-time bioenergetics. We validated that extracellular vesicles derived from activated platelets contain the necessary mitochondrial machinery to respirate and generate energy. Moreover, neutrophils and monocytes efficiently captured platelet-derived extracellular vesicles, enhancing their mitochondrial fitness. This process required functional mitochondria from donor platelets, as it was abolished by the inactivation of extracellular mitochondria using mitochondrial poison. Together, the data suggest that extracellular mitochondria produced by platelets may support other metabolic functions through transcellular bioenergetics.

Effect of COVID-19 Vaccines on the Prevention and Severity of Omicron Strain in Liver Transplant Patient

Background: Because it is still not possible to accurately determine whether the injected vaccines affect the disease incidence and mortality or not in the newly diagnosed strains, the present study aimed to investigate the effect of injected coronavirus disease 2019 (COVID-19) vaccines on the mortality rate among liver transplant patients infected with COVID-19 in Mashhad, Iran. Methods: This prospective cross-sectional study was conducted on liver transplant patients with moderate to severe COVID-19 referred to Montaseriyeh Hospital, Mashhad, Iran, from December 2021 to March 2022. The relationship between mortality due to Omicron strain was assessed with various variables. Results: In general, 97 liver transplant recipients were entered into the present study. Vaccine failure was reported in 43.5% of liver recipients. About 30% of the patients had not received any COVID-19 vaccination, and 2.9%, 40%, and 27.1% had received one, two, and three dosages of COVID-19 vaccination, respectively. Infection with COVID-19 was the cause of mortality in 11.3% of patients. No significant relationship was reported between mortality and the consumption of immunosuppressive agents (P &gt; 0.05). Multiple linear regression showed that the number of received vaccine dosages was predictive of mortality due to infection with the Omicron variant in liver recipients (β = 0.13; P &lt; 0.005). Conclusions: It was found that mortality due to COVID-19 vaccination was higher among the patients with fewer COVID-19 vaccination dosages and, consequently, could be related to vaccine-induced immunity in liver transplant recipients. However, due to the high vaccine failure rate, it seems that neutralizing antibody activity against Omicron variants is high.

Comparison of IgG and Neutralizing Antibody Response After Pfizer BioNTech COVID-19 Vaccine Among Iraqi Individuals

SARS-C0V-2 has quickly caused a pandemic. The distribution of vaccines is presently underway in an effort to stop the viral transmission and stop fatalities, several vaccinations have been created to decrease COVID virus disease, in 2019, the development of vaccine-induced population immunity is an important global strategy. Review of the anti-spike protein receptor-binding domain (S-RBD) a person's level of immune response to antibody strategy can be used to assess SARS-CoV-2 viral infection in 2019. Their efficacy, safety, and immunogenicity in various population are not thoroughly understood. The objective of this study was to evaluate the vaccinations adverse effects as well as determine the immunogenicity of the messenger ribonucleic acid (mRNA) BNT162b2 vaccines through the production of IgG and neutralizing antibodies against the protein s subunit. A total of 41 vaccinated individuals with Pfizer-BioNTech COVID-19 vaccine, as well as (10) non vaccinated were included in the study. Measurements of Neutralizing antibody (Nab) levels and CoV-IgG levels were tested by fluorescence Immunochromatographic assay. IgG and Nab levels showed a significant difference between its level in the sera of vaccinated and controls (p&lt;0.05). This means the majority of immunization recipients between the ages of 18 -50 years can develop an immunological response to the SARS-Cov-2 vaccine.

SARS-CoV-2 Immunity in Hematopoietic Stem Cell Transplant and Cell Therapy Recipients: What Do We Know, and What Remains to Be Determined?

Hematopoietic stem cell transplantation (HSCT) results in profound immunosuppression for the first few months after the procedure, requiring patients to be revaccinated against childhood vaccine-preventable infectious diseases. Patients who undergo allo-HSCT are at high risk of bacterial, fungal, and viral infections, with infectious complications responsible for at least one third of deaths. Even before the COVID-19 pandemic, respiratory virus infections were known to be more severe in HSCT recipients. The pandemic has highlighted the vulnerability of HSCT recipients, who experience an increased risk of morbidity and mortality after COVID-19 compared with healthy populations due to their severe immunodeficiency status. However, the current pandemic has also provided an exceptional scenario to better understand the immune response to SARS-CoV-2 cases and mRNA vaccines in HSCT recipients, including those receiving CD19-directed chimeric antigen receptor T cell (CAR-T) therapy. Researchers have focused on the role of the immune system in protecting against severe SARS-CoV-2 in patients with hematologic malignancies, including HSCT recipients. Insights gained during the pandemic will likely soon be used to improve preventive strategies in this population against viral infections in the near future. This narrative review summarizes the current knowledge on SARS-CoV-2 immunity in HSCT and cell therapy recipients following SARS-CoV-2 cases or vaccination.