Extrafollicular B cell responses correlate with neutralizing antibodies and morbidity in COVID-19.

A wide spectrum of clinical manifestations has become a hallmark of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) COVID-19 pandemic, although the immunological underpinnings of diverse disease outcomes remain to be defined. We performed detailed characterization of B cell responses through high-dimensional flow cytometry to reveal substantial heterogeneity in both effector and immature populations. More notably, critically ill patients displayed hallmarks of extrafollicular B cell activation and shared B cell repertoire features previously described in autoimmune settings. Extrafollicular activation correlated strongly with large antibody-secreting cell expansion and early production of high concentrations of SARS-CoV-2-specific neutralizing antibodies. Yet, these patients had severe disease with elevated inflammatory biomarkers, multiorgan failure and death. Overall, these findings strongly suggest a pathogenic role for immune activation in subsets of patients with COVID-19. Our study provides further evidence that targeted immunomodulatory therapy may be beneficial in specific patient subpopulations and can be informed by careful immune profiling.

Encephalopathy and Encephalitis Associated with Cerebrospinal Fluid Cytokine Alterations and Coronavirus Disease, Atlanta, Georgia, USA, 2020.

There are few detailed investigations of neurologic complications in severe acute respiratory syndrome coronavirus 2 infection. We describe 3 patients with laboratory-confirmed coronavirus disease who had encephalopathy and encephalitis develop. Neuroimaging showed nonenhancing unilateral, bilateral, and midline changes not readily attributable to vascular causes. All 3 patients had increased cerebrospinal fluid (CSF) levels of anti-S1 IgM. One patient who died also had increased levels of anti-envelope protein IgM. CSF analysis also showed markedly increased levels of interleukin (IL)-6, IL-8, and IL-10, but severe acute respiratory syndrome coronavirus 2 was not identified in any CSF sample. These changes provide evidence of CSF periinfectious/postinfectious inflammatory changes during coronavirus disease with neurologic complications.

Antibody Profiles According to Mild or Severe SARS-CoV-2 Infection, Atlanta, Georgia, USA, 2020.

Among patients with coronavirus disease (COVID-19), IgM levels increased early after symptom onset for those with mild and severe disease, but IgG levels increased early only in those with severe disease. A similar pattern was observed in a separate serosurveillance cohort. Mild COVID-19 should be investigated separately from severe COVID-19.

Interleukin 9 alterations linked to alzheimer disease in african americans.

OBJECTIVE: Compared to older Caucasians, older African Americans have higher risks of developing Alzheimer disease (AD) and lower cerebrospinal fluid (CSF) tau biomarker levels. It is not known whether tau-related differences begin earlier in life or whether race modifies other AD-related biomarkers such as inflammatory proteins. METHODS: We performed multiplex cytokine analysis in a healthy middle-aged cohort with family history of AD (n = 68) and an older cohort (n = 125) with normal cognition (NC), mild cognitive impairment, or AD dementia. After determining baseline interleukin (IL)-9 level and AD-associated IL-9 change to differ according to race, we performed immunohistochemical analysis for proteins mechanistically linked to IL-9 in brains of African Americans and Caucasians (n = 38), and analyzed postmortem IL-9-related gene expression profiles in the publicly available Mount Sinai cohort (26 African Americans and 180 Caucasians). RESULTS: Compared to Caucasians with NC, African Americans with NC had lower CSF tau, p-Tau181 , and IL-9 levels in both living cohorts. Conversely, AD was only correlated with increased CSF IL-9 levels in African Americans but not Caucasians. Immunohistochemical analysis revealed perivascular, neuronal, and glial cells immunoreactive to IL-9, and quantitative analysis in independent US cohorts showed AD to correlate with molecular changes (upstream differentiation marker and downstream effector cell marker) of IL-9 upregulation only in African Americans but not Caucasians. INTERPRETATION: Baseline and AD-associated IL-9 differences between African Americans and Caucasians point to distinct molecular phenotypes for AD according to ancestry. Genetic and nongenetic factors need to be considered in future AD research involving unique populations. ANN NEUROL 2019;86:407-418.

CSF IL-8 Associated with Response to Gene Therapy in a Case Series of Spinal Muscular Atrophy.

Gene therapies have greatly changed the outlook in spinal muscular atrophy (SMA), and this disorder provides a rare opportunity to study longitudinal biomarker changes correlated with reduced disease burden and improved clinical outcomes. Recent work suggests clinical response to correlate with declining cerebrospinal fluid (CSF) levels of the neurodegenerative marker neurofilament light chain (NfL) in children receiving serial anti-sense oligonucleotide therapy. However, change in CSF NfL levels is no longer a practical biomarker as more children undergo single-dose gene replacement therapy. Here we leverage serial CSF samples (median of 4 per child) collected in 13 children with SMA undergoing anti-sense oligonucleotide therapy to characterize the longitudinal profiles of NfL as well as inflammatory and neuronal proteins. In contrast to neurodegeneration in adults, we found NfL levels to first decrease following initiation of treatment but then increase upon further treatment and improved motor functions. We then examined additional CSF inflammatory and neuronal markers for linear association with motor function during SMA treatment. We identified longitudinal IL-8 levels to inversely correlate with motor functions determined by clinical examination (F(1, 47) = 12.903, p = 0.001) or electromyography in the abductor pollicis brevis muscle (p = 0.064). In keeping with this, lower baseline IL-8 levels were associated with better longitudinal outcomes, even though this difference diminished over 2 years in the younger group. We thus propose CSF IL-8 as a biomarker for baseline function and short-term treatment response in SMA, and a candidate biomarker for future treatment trials in other neurodegenerative disorders.

Race modifies default mode connectivity in Alzheimer's disease.

Background: Older African Americans are more likely to develop Alzheimer's disease (AD) than older Caucasians, and this difference cannot be readily explained by cerebrovascular and socioeconomic factors alone. We previously showed that mild cognitive impairment and AD dementia were associated with attenuated increases in the cerebrospinal fluid (CSF) levels of total and phosphorylated tau in African Americans compared to Caucasians, even though there was no difference in beta-amyloid 1-42 level between the two races. Methods: We extended our work by analyzing early functional magnetic resonance imaging (fMRI) biomarkers of the default mode network in older African Americans and Caucasians. We calculated connectivity between nodes of the regions belonging to the various default mode network subsystems and correlated these imaging biomarkers with non-imaging biomarkers implicated in AD (CSF amyloid, total tau, and cognitive performance). Results: We found that race modifies the relationship between functional connectivity of default mode network subsystems and cognitive performance, tau, and amyloid levels. Conclusion: These findings provide further support that race modifies the AD phenotypes downstream from cerebral amyloid deposition, and identifies key inter-subsystem connections for deep imaging and neuropathologic characterization.

Cross-sectional IgM and IgG profiles in SARS-CoV-2 infection.

Background: Accurate serological assays can improve the early diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, but few studies have compared performance characteristics between assays in symptomatic and recovered patients. Methods: We recruited 32 patients who had 2019 coronavirus disease (COVID-19; 18 hospitalized and actively symptomatic, 14 recovered mild cases), and measured levels of IgM (against the full-length S1 or the highly homologous SARS-CoV E protein) and IgG (against S1 receptor binding domain [RBD]). We performed the same analysis in 103 pre-2020 healthy adult control (HC) participants and 13 participants who had negative molecular testing for SARS-CoV-2. Results: Anti-S1-RBD IgG levels were very elevated within days of symptom onset for hospitalized patients (median 2.04 optical density [OD], vs. 0.12 in HC). People who recovered from milder COVID-19 only reached similar IgG levels 28 days after symptom onset. IgM levels were elevated early in both groups (median 1.91 and 2.12 vs. 1.14 OD in HC for anti-S1 IgM, 2.23 and 2.26 vs 1.52 in HC for anti-E IgM), with downward trends in hospitalized cases having longer disease duration. The combination of the two IgM levels showed similar sensitivity for COVID-19 as IgG but greater specificity, and identified 4/10 people (vs. 3/10 by IgG) with prior symptoms and negative molecular testing to have had COVID-19. Conclusions: Disease severity and timing both influence levels of IgM and IgG against SARS-CoV-2, with IgG better for early detection of severe cases but IgM more suited for early detection of milder cases.

Dominant extrafollicular B cell responses in severe COVID-19 disease correlate with robust viral-specific antibody production but poor clinical outcomes.

A wide clinical spectrum has become a hallmark of the SARS-CoV-2 (COVID-19) pandemic, although its immunologic underpinnings remain to be defined. We have performed deep characterization of B cell responses through high-dimensional flow cytometry to reveal substantial heterogeneity in both effector and immature populations. More notably, critically ill patients displayed hallmarks of extrafollicular B cell activation as previously described in autoimmune settings. Extrafollicular activation correlated strongly with large antibody secreting cell expansion and early production of high levels of SARS-CoV-2-specific antibodies. Yet, these patients fared poorly with elevated inflammatory biomarkers, multi-organ failure, and death. Combined, the findings strongly indicate a major pathogenic role for immune activation in subsets of COVID-19 patients. Our study suggests that, as in autoimmunity, targeted immunomodulatory therapy may be beneficial in specific patient subpopulations that can be identified by careful immune profiling.

Knowledge and Attitudes in Alzheimer's Disease in a Cohort of Older African Americans and Caucasians.

African American participation in Alzheimer's disease (AD) research studies has been historically low. To determine whether older African Americans and Caucasians had different knowledge or attitudes related to AD, we administered the Alzheimer's Disease Knowledge Scale (ADKS) to 67 older African Americans and 140 older caucasians in the greater Atlanta area as well as questions targeting locus of control over general health and AD risks. Older African Americans scored slightly lower on ADKS than older caucasians, with race only accounting for 1.57 (95% confidence interval [CI] 0.57-2.61, P < .001) points of difference in a multivariate model. Attitudes toward AD were also similar between the 2 groups but 1 (35.7%) in 3 adults reported control over general health but not AD risks. In addition to enhancing education content in outreach efforts, there is an urgent need to address the perception that future AD risks are beyond one's own internal control.