Grill, Diane E.

Older adults experience declining influenza vaccine-induced immunity and are at higher risk of influenza and its complications. For this reason, high dose (e.g., Fluzone) and adjuvanted (e.g., Fluad) vaccines are preferentially recommended for people age 65 years and older. However, T cell transcriptional activity shaping the humoral immune responses to Fluzone and Fluad vaccines in older adults is still poorly understood. We designed a study of 234 older adults (≥65 years old) who were randomly allocated to receive Fluzone or Fluad vaccine and provided blood samples at baseline and at Day 28 after immunization. We measured the humoral immune responses (hemagglutination inhibition/HAI antibody titer) to influenza A/H3N2 and performed mRNA-Seq transcriptional profiling in purified CD4+ T cells, in order to identify T cell signatures that might explain differences in humoral immune response by vaccine type. Given the large differences in formulation (higher antigen dose vs adjuvant), our hypothesis was that each vaccine elicited a distinct transcriptomic response after vaccination. Thus, the main focus of our study was to identify the differential gene expression influencing the antibody titer in the two vaccine groups. Our analyses identified three differentially expressed, functionally linked genes/proteins in CD4+ T cells: the calcium/calmodulin dependent serine/threonine kinase IV (CaMKIV); its regulator the TMEM38B/transmembrane protein 38B, involved in maintenance of intracellular Ca2+ release; and the transcriptional coactivator CBP/CREB binding protein, as regulators of transcriptional activity/function in CD4+ T cells that impact differences in immune response by vaccine type. Significantly enriched T cell-specific pathways/biological processes were also identified that point to the importance of genes/proteins involved in Th1/Th2 cell differentiation, IL-17 signaling, calcium signaling, Notch signaling, MAPK signaling, and regulation of TRP cation Ca2+ channels in humoral immunity after influenza vaccination. In summary, we identified the genes/proteins and pathways essential for cell activation and function in CD4+ T cells that are associated with differences in influenza vaccine-induced humoral immunity by vaccine type. These findings provide an additional mechanistic perspective for achieving protective immunity in older adults.

As an extremely contagious pathogen, a high rate of vaccine coverage and the durability of vaccine-induced immunity are key factors to control and eliminate measles. Herein, we assessed the seroprevalence of antibodies specific to measles in a cohort of 1393 adults (20–44 years old). ELISA results showed a nontrivial proportion of 37.6% study subjects being negative for measles immunoglobulin G (IgG). We also found significant influences of sex and age of the study cohort on the IgG level. Our findings suggest that even within a highly vaccinated population, a subset of individuals may still have sub-optimal immunity against measles and potentially be susceptible during any future measles outbreaks.

AbstractBackgroundA third dose of measles-mumps-rubella vaccine (MMR3) is recommended in mumps outbreak scenarios, but the immune response and the need for widespread use of MMR3 remain uncertain. Herein, we characterized measles-specific immune responses to MMR3 in a cohort of 232 healthy subjects.MethodsSerum and peripheral blood mononuclear cells (PBMCs) were sampled at day 0 and day 28 after MMR3. Measles-specific binding and neutralizing antibodies were quantified in sera by enzyme-linked immunosorbent assay and a microneutralization assay, respectively. PBMCs were stimulated with inactivated measles virus, and the release of cytokines/chemokines was assessed by a multiplex assay. Demographic variables of subjects were examined for potential correlations with immune outcomes.ResultsOf the study participants, 95.69% and 100% were seropositive at day 0 and day 28, respectively. Antibody avidity significantly increased from 38.08% at day 0 to 42.8% at day 28 (P = .00026). Neutralizing antibodies were significantly enhanced, from 928.7 at day 0 to 1289.64 mIU/mL at day 28 (P = .0001). Meanwhile, cytokine/chemokine responses remained largely unchanged. Body mass index was significantly correlated with the levels of inflammatory cytokines/chemokines.ConclusionsMeasles-specific humoral immune responses, but not cellular responses, were enhanced after MMR3 receipt, extending current understanding of immune responses to MMR3 and supporting MMR3 administration to seronegative or high-risk individuals.

Many individuals travel to high altitude each year. Acclimatization to altitude occurs over the course of several days as the body adequately adapts to function in an environment with reduced partial pressure of oxygen. However, with a faster accent to attitude, comes an increased potential for maladaptations to occur, leading to the development of acute mountain sickness (AMS). Each year scientists and support workers are transported by plane from McMurdo Station in Antarctica (sea level) to the Amundsen‐Scott South Pole Station (2835m). This uniform and rapid deployment to altitude provides a unique opportunity to study the effects of hypobaric hypoxia on gene expression, which may help to illustrate the body’s ability to acclimatize to these environmental conditions. Purpose To detect pathway specific gene expression changes associated with the development of AMS and help identify potential targets that may aid in the prediction of risk in the development of AMS symptoms due to rapid exposure to high altitude. Methods Venous blood samples were collected from 53 (height 176.65±8.91cm, weight: 80.49±14.36kg) healthy subjects (38 (27 males; 11 females) that did not develop AMS and 15 (10 males; 5 females) that did develop AMS, as defined by the Lake Louis symptom questionnaire, collected at 2 different time points, with the first being at sea level and the second being after 48hr of altitude exposure). Microarray analysis was performed on the peripheral blood mononuclear cells (PBMCs) from the collected samples, and a logistic regression was performed to determine probe set association with AMS. Results There was a total of 178 significant (p<0.05) probe sets, with 156 of the probe sets being associated with AMS and 22 of the probe sets being associated with no AMS. The probe sets were entered into the Reactome Pathway Database (reactome.org). Pathways identified in association with AMS involved immune system pathways (interleukin signaling) and cellular responses to stimuli pathways (oxidative stress induced senescence signaling), and gene transcription pathways (mitochondrial biogenesis signaling, differentiation of hematopoietic stem cells). Interestingly, pathways identified in association with no development of AMS involved cell cycling pathways (mitotic signaling), chromatin organization pathways (chromatin modifying enzymes), metabolism pathways (utilization of ketone bodies) and the circadian clock pathway (circadian gene expression signaling). Conclusion These findings indicate potential maladaptive responses within the immune system and mitochondrial function, may play a key role in why some individuals develop AMS symptoms. An individual’s ability to sufficiently utilize different metabolic fuel sources and adapt their circadian rhythm may also prevent the development of AMS symptoms.

BACKGROUND. Nearly half of strokes in non-valvular atrial fibrillation (NVAF) are due to non-cardioembolic mechanisms including carotid disease, lacune, watershed, venous sinus thrombosis, or hemorrhage. Tools capable of identifying those AF patients most likely to suffer a cardioembolic complication of AF would be very helpful for deciding which patients to treat with anticoagulants compared to aspirin. CHA 2 DS 2 -VASc has been advocated as an improved stroke risk assessment tool for NVAF patients. METHODS. CHA 2 DS 2 -VASc was compared to CHADS 2 for the prediction of left atrial appendage thrombus (LAAT), and association (Spearman correlation) with spontaneous echo contrast (SEC), left atrium appendage emptying velocity (LAAEV), left atrium volume index (LAVI) in consecutive NVAF patients undergoing echocardiographic study (10/1/2007 - 9/30/2009). RESULTS. 525 NVAF patients (age 62±13 years; 25% women; 28% persistent AF and 17% permanent AF) were parsed by extent of atrial blood stasis/LAAT ( Table ). CHA 2 DS 2 -VASc and CHADS 2 were similar for the prediction of LAAT (Figure). Measures of SEC intensity (0.416 vs 0.414;), LAAEV (-0.393 vs -0.344), and LAVI (0.322 vs 0.303) carried similarly associations with CHA 2 DS 2 -VASc and CHADS 2 scores. CONCLUSION. The challenge of stroke prevention in NVAF is balancing the risk and benefit of anticoagulant therapy. CHA 2 DS 2 -VASc does not improve the identification of patients with LAAT or low atrial mechanical function compared to CHADS 2 . Moreover CHA 2 DS 2 -VASc appears to overestimate the score of low risk patients for whom antiplatelet therapy would be sufficient and is more cumbersome compared to the original CHADS 2 .

AbstractRare cases of COVID‐19 vaccinated individuals develop anti‐platelet factor 4 (PF4) antibodies that cause thrombocytopenia and thrombotic complications, a syndrome referred to as vaccine‐induced immune thrombotic thrombocytopenia (VITT). Currently, information on the characteristics and persistence of anti‐PF4 antibodies that cause VITT after Ad26.COV2.S vaccination is limited, and available diagnostic assays fail to differentiate Ad26.COV2.S and ChAdOx1 nCoV‐19‐associated VITT from similar clinical disorders, namely heparin‐induced thrombocytopenia (HIT) and spontaneous HIT. Here we demonstrate that while Ad26.COV2.S‐associated VITT patients are uniformly strongly positive in PF4‐polyanion enzyme‐linked immunosorbent assays (ELISAs); they are frequently negative in the serotonin release assay (SRA). The PF4‐dependent p‐selectin expression assay (PEA) that uses platelets treated with PF4 rather than heparin consistently diagnosed Ad26.COV2.S‐associated VITT. Most Ad26.COV2.S‐associated VITT antibodies persisted for >5 months in PF4‐polyanion ELISAs, while the PEA became negative earlier. Two patients had otherwise unexplained mild persistent thrombocytopenia (140‐150 x 103/µL) 6 months after acute presentation. From an epidemiological perspective, differentiating VITT from spontaneous HIT, another entity that develops in the absence of proximate heparin exposure, and HIT is important, but currently available PF4‐polyanion ELISAs and functional assay are non‐specific and detect all three conditions. Here, we report that a novel un‐complexed PF4 ELISA specifically differentiates VITT, secondary to both Ad26.COV2.S and ChAdOx1 nCoV‐19, from both spontaneous HIT, HIT and commonly‐encountered HIT‐suspected patients who are PF4/polyanion ELISA‐positive but negative in functional assays. In summary, Ad26.COV2.S‐associated VITT antibodies are persistent, and the un‐complexed PF4 ELISA appears to be both sensitive and specific for VITT diagnosis.

Abstract The durability of protective humoral immunity after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and infection is largely dependent on the generation and persistence of antigen-specific isotype-switched memory B cells (MBCs) and long-lived plasma cells that reside in the bone marrow and secrete high-affinity neutralizing antibodies. The reactivity of vaccine-induced MBCs to emerging clinically significant SARS-CoV-2 variants of concern (VoCs) is largely unknown. In a longitudinal cohort study (up to 6 months following coronavirus disease 2019 messenger RNA vaccination), we measured MBCs in concert with other functional antibody measures. We found statistically significant differences between the frequencies of MBCs responding to homologous and VoC (Beta, Gamma, and Delta) receptor-binding domains after vaccination that persisted over time. In concert with a waning antibody response, the reduced MBC response to VoCs could translate to a weaker subsequent recall immune response and increased susceptibility to the emerging SARS-CoV-2 variant strains after vaccination.

The novel findings of this study demonstrate that intravascular volume profiles among the patients with chronic heart failure (HF) vary substantially even with similar clinical compensation. Importantly, a profile of blood volume (BV) expansion (compared with a normal BV) is associated with lower HF mortality/morbidity. Furthermore, RBC polycythemia is common and independently associated with improved outcomes. These observations support BV expansion with RBC polycythemia as a compensatory mechanism in chronic HF.

Objective To identify novel genes and pathways associated with acute mountain sickness (AMS). Background The uniform, rapid transfer of adults from McMurdo Station (sea level, SL) in Antarctica to the South Pole (SP, 2835m) provides a unique opportunity to study changes in gene expression related to the body's adaptation to hypobaric hypoxia. Methods Venous blood was drawn at SL and after 2 d at SP in 98 subjects (age 37±9 y, 70% male). Peripheral blood mononuclear cells (PBMCs) were isolated and microarray analysis of the mRNA isolated from these cells was performed (Affymetrix HG U133 Plus 2 microarray chip). Analysis and the computation of expression fold changes and phenotypic regression were performed using the Bioconductor package in R. Pathway analysis was performed using MetaCore™. Results ~3200 probe sets with sig. p‐values (p<0.05) and fold changes for each subject were used in a binary logistic regression with the presence or absence of AMS during the 2 d at altitude. Corresponding p‐values and z‐values were entered into MetaCore™ for pathways analysis. Identified pathways included smooth muscle contraction, calcium signaling, and acetylcholine regulation of nerve impulses. Conclusions Probe sets associated with the presence of AMS had a significant representation in pathways involving aspects of the autonomic nervous system including smooth muscle contraction and nerve signaling. NSF B‐179‐M.

Objective To identify novel genes that change expression in healthy adults exposed to hypobaric hypoxia. Background The uniform and rapid transfer of adults from McMurdo Station (sea level, SL) in Antarctica to the South Pole (2835m, SP) provides a unique opportunity to study the changes in gene expression related to the body's adaptation to high altitude. We hypothesized that a large number of genes would change expression and that many of these genes would be associated with inflammatory processes. Methods Peripheral venous blood was drawn at SL and after 2 d at SP in 98 subjects (age 37±9 y, 70% male). Peripheral blood mononuclear cells (PBMCs) were isolated and microarray analysis of the mRNA isolated from these cells was performed (Affymetrix HG U133 Plus 2 microarray chip). Analysis and the computation of expression fold changes was performed using the Bioconductor package in R. Pathway analysis was performed using MetaCore™. Results 1118 probe sets with significant p‐values (p<0.05) and fold changes were identified and entered into MetaCore™. Several pathways including oxidative phosphorylation, cytoskeletal remodeling, and platelet aggregation were identified as having significant representation in the restricted data set. Conclusion Several pathways indicating significantly increased activity in PBMCs were identified. This is indicative of an increased inflammatory response. NSF B‐179‐M.