Henrik Zetterberg

Blood-based immunophenotyping of T cell profiles in patients with neurodegenerative disorders.

BACKGROUND There is increasing evidence for the role of central and peripheral inflammation across neurodegenerative disorders, with animal models and post-mortem studies identifying T-cell infiltration in the brain associated with pathology and neurodegeneration. Peripheral T-cell changes have been measured in Alzheimer's disease (AD), dementia with Lewy bodies (DLB), frontotemporal dementia (FTD) and progressive supranuclear palsy (PSP). This study examines a unique cohort of blood-based T-cell profiles across a range of neurodegenerative dementias including AD, DLB, FTD, corticobasal syndrome (CBS), PSP, and aged-matched healthy controls. Then it also explores their associations with dementia-relevant plasma biomarkers and clinical outcomes. METHODS Freshly prepared peripheral blood mononuclear cells (PBMCs) from 174 participants (AD = 20, DLB = 24, FTD = 19, CBS = 18, PSP = 58, controls = 35) were studied using a flow-cytometry panel designed to analyse major T-cell subpopulations, including memory and T-helper subtypes. Neurodegeneration-relevant biomarkers (p-tau217, p-tau231, GFAP, NfL, and A-beta42/40) were measured in plasma samples. T-cell populations were compared between groups and in association with biomarkers, and principal components analysis (PCA) was used to identify T-cell profiles and their association with dementia-relevant biomarkers in diagnostic classification and survival prediction. RESULTS There was a significant reduction in the fraction of CD3+ cells in patients with DLB compared to other diagnostic groups, and an increase in relative Th1/17-like cell levels in patients with FTD compared to controls. This increase in Th1/17-like cells correlated with NfL and GFAP plasma levels in patients with FTD. PCA identified five components primarily representing CD4+ memory cell population subsets. After sex and age adjustments, component 4 marked by effector memory types including Th2-like, Th-like1 and Th1/17-like cells was a significant predictor of FTD, however was not as accurate as plasma NfL. Higher scores in specific T-cell components (1 and 3) were associated with reduced mortality across all diseases, with component 3 remaining a significant predictor even when controlling for traditional neurodegenerative biomarkers like NfL and p-tau217. CONCLUSIONS This study provides evidence that T-cell dysregulation is not unified in patients with neurodegenerative diseases. We observe different involvement across different dementia types establishing adaptive immunity as a key contributor to disease heterogeneity. However, although plasma biomarkers such as NfL and p-tau217 exhibit superior diagnostic accuracy for clinical classification, peripheral T-cell signature were associated with survival outcomes across diagnostic groups, highlighting their promise for prognostic applications and disease monitoring. The characterisation of T-cell populations across neurodegenerative conditions may inform target development and patient stratification for new interventional trials.

Educational attainment and sex modulate clinical outcomes in genetic frontotemporal dementia

Abstract Individuals with autosomal dominant frontotemporal dementia (FTD) exhibit considerable variability in disease onset and progression. Both modifiable and non-modifiable factors—such as sex, educational attainment or geographic region of residence—may contribute to this heterogeneity, potentially through their influence on cognitive reserve. The aim of the present study was to investigate the role of cognitive reserve modulators within the Genetic Frontotemporal dementia Initiative (GENFI) cohort. To this end, we used functional MRI (i.e. spatial chronnectome measures) and neurodegenerative markers (i.e. plasma neurofilament light chains levels) to determine disease stage using a Discriminative Event-Based Model (DEBM). We then examined how potential modulators influence the relationship between disease stage and cognitive performance. We analysed a total of 711 participants, including 106 patients with genetic FTD, 325 presymptomatic mutation carriers and 280 non-carriers healthy controls. Female participants showed a weaker association between disease stage and cognitive performance compared to males (P < 0.001), with difference becoming progressively more pronounced across symptomatic stages. Educational attainment exhibited a similar effect: individuals with higher education demonstrated an attenuated association compared to those with secondary or primary schooling (P < 0.001), with differences already detectable at prodromal disease stages. The effect of geographical region of residence was associated with education levels, but appeared to have an indirect and less strong influence. In summary, sex and educational attainment significantly affect the development and maintenance of cognitive reserve in individuals with genetic FTD. These findings underscore the importance of identifying disease-modifying interventions since the presymptomatic stages of the disease.

Defining the underlying pathology of corticobasal syndrome using clinical features and biomarkers.

Neurobiological correlates of longitudinal grey matter volume changes in preclinical Alzheimer’s disease

Structural brain changes during the earliest asymptomatic stages of Alzheimer’s disease (AD) remain poorly understood. Previous research in preclinical AD shows heterogeneous findings, reporting both subtle neuronal loss and paradoxical increases in grey matter (GM) volume. This study applies an extensive cerebrospinal fluid (CSF) biomarker panel to better understand the biological processes underlying longitudinal GM changes in cognitively unimpaired (CU) adults, spanning the amyloid/tau (AT) continuum. We analysed data from 627 CU individuals from three longitudinal cohorts (ALFA+, Wisconsin ADRC, WRAP), with repeated MRI (3.5 ± 0.9 years) and baseline CSF biomarkers from the NeuroToolKit panel (Roche Diagnostics). Using non-negative matrix factorization, we decomposed the CSF biomarker levels into six latent components, reflecting amyloid-β (Aβ) pathology, tau-related pathophysiology with synaptic injury, neuroaxonal injury, microglial reactivity, astrocytic reactivity, and cytokine signalling. We tested associations between component weights and voxel-wise longitudinal GM volume changes using single-component and a joint-all components model. Analyses were performed across the full sample and stratified by AT status. Associations with longitudinal cognitive performance (PACC) were assessed using linear mixed-effects models. The Aβ pathology component was the strongest and most widespread predictor of longitudinal GM atrophy, predominantly in temporal and frontal regions, also when controlling for tau pathophysiology, neuroaxonal injury, or neuroinflammatory components. Higher Aβ pathology scores were also associated with cognitive decline. The component capturing tau-related pathophysiology and synaptic injury initially associated with GM loss but lost significance after accounting for other biomarker components. In contrast, components reflecting microglial reactivity, astrocytic reactivity, and cytokine signalling were associated with longitudinal GM volume increases, with effects varying by AT stage. In this large longitudinal sample of asymptomatic individuals, the Aβ-dominant biomarker component showed the strongest association with longitudinal GM atrophy and cognitive decline, beyond the effects of tau pathophysiology and neuroaxonal injury. While glial and inflammatory processes may contribute to transient GM increases in preclinical AD. A better understanding of these dynamic relationships between structural brain changes and various biological pathways at the earliest stages of AD is crucial to inform the development of interventions before irreversible neurodegeneration occurs.

Blood-based multimodal biomarker models for differentiating early-onset Alzheimer’s disease from frontotemporal dementia: a longitudinal study of early-onset dementia and family members (LEAF) study