SARS-CoV-2 mRNA vaccination elicits a robust and persistent T follicular helper cell response in humans.

SARS-CoV-2 mRNA vaccines induce robust anti-spike (S) antibody and CD4+ T cell responses. It is not yet clear whether vaccine-induced follicular helper CD4+ T (TFH) cell responses contribute to this outstanding immunogenicity. Using fine-needle aspiration of draining axillary lymph nodes from individuals who received the BNT162b2 mRNA vaccine, we evaluated the T cell receptor sequences and phenotype of lymph node TFH. Mining of the responding TFH T cell receptor repertoire revealed a strikingly immunodominant HLA-DPB1∗04-restricted response to S167-180 in individuals with this allele, which is among the most common HLA alleles in humans. Paired blood and lymph node specimens show that while circulating S-specific TFH cells peak one week after the second immunization, S-specific TFH persist at nearly constant frequencies for at least six months. Collectively, our results underscore the key role that robust TFH cell responses play in establishing long-term immunity by this efficacious human vaccine.

Influenza vaccination stimulates maturation of the human T follicular helper cell response.

The differentiation and specificity of human CD4+ T follicular helper cells (TFH cells) after influenza vaccination have been poorly defined. Here we profiled blood and draining lymph node (LN) samples from human volunteers for over 2 years after two influenza vaccines were administered 1 year apart to define the evolution of the CD4+ TFH cell response. The first vaccination induced an increase in the frequency of circulating TFH (cTFH) and LN TFH cells at week 1 postvaccination. This increase was transient for cTFH cells, whereas the LN TFH cells further expanded during week 2 and remained elevated in frequency for at least 3 months. We observed several distinct subsets of TFH cells in the LN, including pre-TFH cells, memory TFH cells, germinal center (GC) TFH cells and interleukin-10+ TFH cell subsets beginning at baseline and at all time points postvaccination. The shift toward a GC TFH cell phenotype occurred with faster kinetics after the second vaccine compared to the first vaccine. We identified several influenza-specific TFH cell clonal lineages, including multiple responses targeting internal influenza virus proteins, and found that each TFH cell state was attainable within a clonal lineage. Thus, human TFH cells form a durable and dynamic multitissue network.

CD4+ T cells exhibit distinct transcriptional phenotypes in the lymph nodes and blood following mRNA vaccination in humans.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and mRNA vaccination induce robust CD4+ T cell responses. Using single-cell transcriptomics, here, we evaluated CD4+ T cells specific for the SARS-CoV-2 spike protein in the blood and draining lymph nodes (dLNs) of individuals 3 months and 6 months after vaccination with the BNT162b2 mRNA vaccine. We analyzed 1,277 spike-specific CD4+ T cells, including 238 defined using Trex, a deep learning-based reverse epitope mapping method to predict antigen specificity. Human dLN spike-specific CD4+ follicular helper T (TFH) cells exhibited heterogeneous phenotypes, including germinal center CD4+ TFH cells and CD4+IL-10+ TFH cells. Analysis of an independent cohort of SARS-CoV-2-infected individuals 3 months and 6 months after infection found spike-specific CD4+ T cell profiles in blood that were distinct from those detected in blood 3 months and 6 months after BNT162b2 vaccination. Our findings provide an atlas of human spike-specific CD4+ T cell transcriptional phenotypes in the dLNs and blood following SARS-CoV-2 vaccination or infection.

SARS-CoV-2 Omicron boosting induces de novo B cell response in humans.

The primary two-dose SARS-CoV-2 mRNA vaccine series are strongly immunogenic in humans, but the emergence of highly infectious variants necessitated additional doses and the development of vaccines aimed at the new variants1-4. SARS-CoV-2 booster immunizations in humans primarily recruit pre-existing memory B cells5-9. However, it remains unclear whether the additional doses induce germinal centre reactions whereby re-engaged B cells can further mature, and whether variant-derived vaccines can elicit responses to variant-specific epitopes. Here we show that boosting with an mRNA vaccine against the original monovalent SARS-CoV-2 mRNA vaccine or the bivalent B.1.351 and B.1.617.2 (Beta/Delta) mRNA vaccine induced robust spike-specific germinal centre B cell responses in humans. The germinal centre response persisted for at least eight weeks, leading to significantly more mutated antigen-specific bone marrow plasma cell and memory B cell compartments. Spike-binding monoclonal antibodies derived from memory B cells isolated from individuals boosted with either the original SARS-CoV-2 spike protein, bivalent Beta/Delta vaccine or a monovalent Omicron BA.1-based vaccine predominantly recognized the original SARS-CoV-2 spike protein. Nonetheless, using a more targeted sorting approach, we isolated monoclonal antibodies that recognized the BA.1 spike protein but not the original SARS-CoV-2 spike protein from individuals who received the mRNA-1273.529 booster; these antibodies were less mutated and recognized novel epitopes within the spike protein, suggesting that they originated from naive B cells. Thus, SARS-CoV-2 booster immunizations in humans induce robust germinal centre B cell responses and can generate de novo B cell responses targeting variant-specific epitopes.

Germinal centre-driven maturation of B cell response to mRNA vaccination.

Germinal centres (GC) are lymphoid structures in which B cells acquire affinity-enhancing somatic hypermutations (SHM), with surviving clones differentiating into memory B cells (MBCs) and long-lived bone marrow plasma cells1-5 (BMPCs). SARS-CoV-2 mRNA vaccination induces a persistent GC response that lasts for at least six months in humans6-8. The fate of responding GC B cells as well as the functional consequences of such persistence remain unknown. Here, we detected SARS-CoV-2 spike protein-specific MBCs in 42 individuals who had received two doses of the SARS-CoV-2 mRNA vaccine BNT162b2 six month earlier. Spike-specific IgG-secreting BMPCs were detected in 9 out of 11 participants. Using a combined approach of sequencing the B cell receptors of responding blood plasmablasts and MBCs, lymph node GC B cells and plasma cells and BMPCs from eight individuals and expression of the corresponding monoclonal antibodies, we tracked the evolution of 1,540 spike-specific B cell clones. On average, early blood spike-specific plasmablasts exhibited the lowest SHM frequencies. By contrast, SHM frequencies of spike-specific GC B cells increased by 3.5-fold within six months after vaccination. Spike-specific MBCs and BMPCs accumulated high levels of SHM, which corresponded with enhanced anti-spike antibody avidity in blood and enhanced affinity as well as neutralization capacity of BMPC-derived monoclonal antibodies. We report how the notable persistence of the GC reaction induced by SARS-CoV-2 mRNA vaccination in humans culminates in affinity-matured long-term antibody responses that potently neutralize the virus.

SARS-CoV-2 mRNA vaccines induce persistent human germinal centre responses.

SARS-CoV-2 mRNA-based vaccines are about 95% effective in preventing COVID-191-5. The dynamics of antibody-secreting plasmablasts and germinal centre B cells induced by these vaccines in humans remain unclear. Here we examined antigen-specific B cell responses in peripheral blood (n = 41) and draining lymph nodes in 14 individuals who had received 2 doses of BNT162b2, an mRNA-based vaccine that encodes the full-length SARS-CoV-2 spike (S) gene1. Circulating IgG- and IgA-secreting plasmablasts that target the S protein peaked one week after the second immunization and then declined, becoming undetectable three weeks later. These plasmablast responses preceded maximal levels of serum anti-S binding and neutralizing antibodies to an early circulating SARS-CoV-2 strain as well as emerging variants, especially in individuals who had previously been infected with SARS-CoV-2 (who produced the most robust serological responses). By examining fine needle aspirates of draining axillary lymph nodes, we identified germinal centre B cells that bound S protein in all participants who were sampled after primary immunization. High frequencies of S-binding germinal centre B cells and plasmablasts were sustained in these draining lymph nodes for at least 12 weeks after the booster immunization. S-binding monoclonal antibodies derived from germinal centre B cells predominantly targeted the receptor-binding domain of the S protein, and fewer clones bound to the N-terminal domain or to epitopes shared with the S proteins of the human betacoronaviruses OC43 and HKU1. These latter cross-reactive B cell clones had higher levels of somatic hypermutation as compared to those that recognized only the SARS-CoV-2 S protein, which suggests a memory B cell origin. Our studies demonstrate that SARS-CoV-2 mRNA-based vaccination of humans induces a persistent germinal centre B cell response, which enables the generation of robust humoral immunity.

Persons with HIV Develop Spike-Specific Lymph Node Germinal Center Responses following SARS-CoV-2 Vaccination.

COVID-19 disproportionately affects persons with HIV (PWH) in worldwide locations with limited access to SARS-CoV-2 vaccines. PWH exhibit impaired immune responses to some, but not all, vaccines. Lymph node (LN) biopsies from PWH demonstrate abnormal LN structure, including dysregulated germinal center (GC) architecture. It is not clear whether LN dysregulation prevents PWH from mounting Ag-specific GC responses in the draining LN following vaccination. To address this issue, we longitudinally collected blood and draining LN fine needle aspiration samples before and after SARS-CoV-2 vaccination from a prospective, observational cohort of 11 PWH on antiretroviral therapy: 2 who received a two-dose mRNA vaccine series and 9 who received a single dose of the Ad26.COV2.S vaccine. Following vaccination, we observed spike-specific Abs, spike-specific B and T cells in the blood, and spike-specific GC B cell and T follicular helper cell responses in the LN of both mRNA vaccine recipients. We detected spike-specific Abs in the blood of all Ad26.COV2.S recipients, and one of six sampled Ad26.COV2.S recipients developed a detectable spike-specific GC B and T follicular helper cell response in the draining LN. Our data show that PWH can mount Ag-specific GC immune responses in the draining LN following SARS-CoV-2 vaccination. Due to the small and diverse nature of this cohort and the limited number of available controls, we are unable to elucidate all potential factors contributing to the infrequent vaccine-induced GC response observed in the Ad26.COV2.S recipients. Our preliminary findings suggest this is a necessary area of future research.

Predictors of pain development for contralateral asymptomatic degenerative rotator cuff tears based on features of an ipsilateral painful cuff tear: a prospective longitudinal cohort study.

BACKGROUND: Prior rotator cuff disease natural history studies have focused on tear-related factors that predict disease progression within a given shoulder. The purpose of this study was to examine both patient- and tear-related characteristics of a painful rotator cuff tear that predict future pain development and functional impairment in a shoulder with a contralateral asymptomatic cuff tear. METHODS: This was a prospective longitudinal cohort study of patients aged ≤65 years who underwent surgery for a painful degenerative rotator cuff tear and possessed an asymptomatic contralateral tear. Patients were followed up prospectively by shoulder ultrasound, physical examination, and functional score assessment. The primary outcome was change in the American Shoulder and Elbow Surgeons (ASES) score at 2 years. Secondary outcomes included the Western Ontario Rotator Cuff Index (WORC) score, Patient-Reported Outcomes Measurement Information System (PROMIS) score, Hospital Anxiety Depression Scale (HADS) depression and anxiety scores, and Veterans RAND-12 (VR-12) mental component score (MCS). RESULTS: Sixty-five patients were included, with a mean follow-up period of 37 months (range, 24-42 months). In 17 patients (26%), contralateral shoulder pain developed at a median of 15.2 months (interquartile range [IQR], 10.5 months). No difference in age, sex, Charlson Comorbidity Index, or occupational demand was noted between patients in whom pain developed and those in whom pain did not develop. In the presenting painful shoulder, there was no difference in baseline tear size, muscle degeneration, or biceps pathology between groups. The mean baseline tear length (8.6 mm vs. 3.8 mm, P = .0008) and width (8.4 mm vs. 3.2 mm, P = .0004) were larger in asymptomatic shoulders in which pain subsequently developed compared with those in which pain did not develop. However, there was no difference in mean tear enlargement (P = .51 for length and P = .90 for width). There were no differences in baseline ASES, WORC, Patient-Reported Outcomes Measurement Information System (PROMIS), or HADS depression and anxiety scores between shoulders in which pain developed and those in which pain did not develop; however, patients in whom pain developed reported a lower baseline VR-12 MCS (53.3 vs. 57.6, P = .04). Shoulders in which pain developed had higher visual analog scale pain scores (2.9 [standard deviation (SD), 2.5] vs. 0.6 [SD, 1.0]; P = .016), lower ASES scores 75 [SD, 33] vs. 100 [SD, 11.6]; P = .001), and significant changes in all WORC scales with pain onset compared with those that remained asymptomatic. The study showed no significant difference in changes in the HADS anxiety and depression scores but found a significant increase in the VR-12 MCS in patients in whom pain developed (7.1 [interquartile range, 12.6] vs. -1.9 [interquartile range, 8.7]; P = .036). CONCLUSION: In one-quarter of patients with painful cuff tears, pain developed in a contralateral asymptomatic cuff tear that resulted in a measurable decline in function within 3 years. Our analysis showed that only the baseline tear size of the asymptomatic shoulder was predictive of pain development. There were no tear-related features of the presenting painful rotator cuff tear or indices of mental health and physical function or occupational demand that were predictive of future pain development at short-term follow-up.

Does surgical intervention alter the natural history of degenerative rotator cuff tears? Comparative analysis from a prospective longitudinal study.

BACKGROUND: The natural history of rotator cuff tears often involves progressive pain development, tear enlargement, and advancing muscle fatty degeneration. Both surgery and conservative management have proven to be effective treatments. Our study purpose was to compare the short- to mid-term effects of rotator cuff repair on shoulder function, progression of tear size, and muscle degeneration compared to controls with asymptomatic tears that developed pain and were managed nonoperatively. METHODS: This comparative study consists of 2 separate longitudinal study arms. The control group consisted of asymptomatic degenerative cuff tears followed until pain development and then managed nonoperatively with continued surveillance. The surgical group consisted of subjects with degenerative tears that failed nonoperative treatment and underwent surgical intervention with a minimum of 2 years follow-up. Outcomes included visual analog scale pain, American Shoulder and Elbow Surgeons, active range of motion, strength, and ultrasonography. RESULTS: There were 83 controls and 65 surgical shoulders. The surgical group was younger at enrollment (58.9 ± 5.3 yr vs. 61.2 ± 7.8 yr, P = .04). The median follow-up for control subjects after pain development was 5.1 years (interquartile range [IQR] 3.6) and the median postoperative follow-up for the surgical group was 3.0 years (IQR 0.2). Baseline tear widths (median 14 mm, IQR 9 vs. 13 mm, IQR 8; P = .45) and tear lengths (median 14 mm, IQR 13 vs. median 11 mm, IQR 8; P = .06) were similar between the surgical group and controls. There were no differences in the baseline prevalence of fatty degeneration of the supraspinatus or infraspinatus muscles between groups (P = .43 and P = .58, respectively). At final follow-up, the surgical group demonstrated significantly lower visual analog scale pain (0 [IQR 2] vs. 3.5 [IQR 4], P = .0002), higher composite American Shoulder and Elbow Surgeons (95 [IQR 13] vs. 65.8 [IQR 32], P = .0002), and activities of daily living scores (29 [IQR 4] vs. 22 [IQR 8], P = .0002), greater abduction strength (69.6 N [standard deviation {SD} 29] vs. 35.9 N [SD 29], P = .0002), greater active forward elevation (155° [SD 8] vs. 142° [SD 28], P = .002), greater active external rotation in abduction (mean 98.5°, SD 12 vs. mean 78.2°, SD 20; P = .0002) compared to controls. Additionally, the prevalence of fatty muscle degeneration was lower in the surgical group for the supraspinatus and infraspinatus (25% vs. 41%, P = .05; 17% vs. 34%, P = .03; respectively). CONCLUSION: This prospective longitudinal study comparing a surgical cohort undergoing rotator cuff repair with a control group treated nonoperatively supports the notion that surgical intervention has the potential to alter the early natural history of degenerative rotator cuff disease. Patients in the surgical group demonstrated clinically relevant differences in pain and functional outcomes. Surgical intervention was protective against progressive muscle degeneration compared to nonoperative treatment.

International Expert Consensus on US Lexicon for Thyroid Nodules.

Multiple US-based systems for risk stratification of thyroid nodules are in use worldwide. Unfortunately, the malignancy probability assigned to a nodule varies, and terms and definitions are not consistent, leading to confusion and making it challenging to compare study results and craft revisions. Consistent application of these systems is further hampered by interobserver variability in identifying the sonographic features on which they are founded. In 2018, an international multidisciplinary group of 19 physicians with expertise in thyroid sonography (termed the International Thyroid Nodule Ultrasound Working Group) was convened with the goal of developing an international system, tentatively called the International Thyroid Imaging Reporting and Data System, or I-TIRADS, in two phases: (phase I) creation of a lexicon and atlas of US descriptors of thyroid nodules and (phase II) development of a system that estimates the malignancy risk of a thyroid nodule. This article presents the methods and results of phase I. The purpose herein is to show what has been accomplished thus far, as well as generate interest in and support for this effort in the global thyroid community.