Differential effects of anti-CD20 therapy on CD4 and CD8 T cells and implication of CD20-expressing CD8 T cells in MS disease activity.

A small proportion of multiple sclerosis (MS) patients develop new disease activity soon after starting anti-CD20 therapy. This activity does not recur with further dosing, possibly reflecting deeper depletion of CD20-expressing cells with repeat infusions. We assessed cellular immune profiles and their association with transient disease activity following anti-CD20 initiation as a window into relapsing disease biology. Peripheral blood mononuclear cells from independent discovery and validation cohorts of MS patients initiating ocrelizumab were assessed for phenotypic and functional profiles using multiparametric flow cytometry. Pretreatment CD20-expressing T cells, especially CD20dimCD8+ T cells with a highly inflammatory and central nervous system (CNS)-homing phenotype, were significantly inversely correlated with pretreatment MRI gadolinium-lesion counts, and also predictive of early disease activity observed after anti-CD20 initiation. Direct removal of pretreatment proinflammatory CD20dimCD8+ T cells had a greater contribution to treatment-associated changes in the CD8+ T cell pool than was the case for CD4+ T cells. Early disease activity following anti-CD20 initiation was not associated with reconstituting CD20dimCD8+ T cells, which were less proinflammatory compared with pretreatment. Similarly, this disease activity did not correlate with early reconstituting B cells, which were predominantly transitional CD19+CD24highCD38high with a more anti-inflammatory profile. We provide insights into the mode-of-action of anti-CD20 and highlight a potential role for CD20dimCD8+ T cells in MS relapse biology; their strong inverse correlation with both pretreatment and early posttreatment disease activity suggests that CD20-expressing CD8+ T cells leaving the circulation (possibly to the CNS) play a particularly early role in the immune cascades involved in relapse development.

The Study of Remyelinating Therapies in Multiple Sclerosis: Visual Outcomes as a Window Into Repair.

INTRODUCTION: Amelioration of disability in multiple sclerosis requires the development of complementary therapies that target neurodegeneration and promote repair. Remyelination is a promising neuroprotective strategy that may protect axons from damage and subsequent neurodegeneration. METHODS: A review of key literature plus additional targeted search of PubMed and Google Scholar was conducted. RESULTS: There has been a rapid expansion of clinical trials studying putative remyelinating candidates, but further growth of the field is limited by the lack of consensus on key aspects of trial design. We have not yet defined the ideal study population, duration of therapy, or the appropriate outcome measures to detect remyelination in humans. The varied natural history of multiple sclerosis, coupled with the short time frame of phase II clinical trials, requires that we develop and validate biomarkers of remyelination that can serve as surrogate endpoints in clinical trials. CONCLUSIONS: We propose that the visual system may be the most well-suited and validated model for the study potential remyelinating agents. In this review, we discuss the pathophysiology of demyelination and summarize the current clinical trial landscape of remyelinating agents. We present some of the challenges in the study of remyelinating agents and discuss current potential biomarkers of remyelination and repair, emphasizing both established and emerging visual outcome measures.

Clearance of cerebral Aß in Alzheimer's disease: reassessing the role of microglia and monocytes.

Deficiency in cerebral amyloid ß-protein (Aß) clearance is implicated in the pathogenesis of the common late-onset forms of Alzheimer's disease (AD). Accumulation of misfolded Aß in the brain is believed to be a net result of imbalance between its production and removal. This in turn may trigger neuroinflammation, progressive synaptic loss, and ultimately cognitive decline. Clearance of cerebral Aß is a complex process mediated by various systems and cell types, including vascular transport across the blood-brain barrier, glymphatic drainage, and engulfment and degradation by resident microglia and infiltrating innate immune cells. Recent studies have highlighted a new, unexpected role for peripheral monocytes and macrophages in restricting cerebral Aß fibrils, and possibly soluble oligomers. In AD transgenic (ADtg) mice, monocyte ablation or inhibition of their migration into the brain exacerbated Aß pathology, while blood enrichment with monocytes and their increased recruitment to plaque lesion sites greatly diminished Aß burden. Profound neuroprotective effects in ADtg mice were further achieved through increased cerebral recruitment of myelomonocytes overexpressing Aß-degrading enzymes. This review summarizes the literature on cellular and molecular mechanisms of cerebral Aß clearance with an emphasis on the role of peripheral monocytes and macrophages in Aß removal.

Trends and Disparities in the Utilization of Thymectomy for Myasthenia Gravis in the United States.

Background and Objectives: In 2016, a randomized controlled trial demonstrated the clinical efficacy of trans-sternal thymectomy for patients with non-thymomatous myasthenia gravis (MG). Whether large-scale changes occurred in clinical practice after this trial is unknown. Methods: We performed a retrospective longitudinal cross-sectional analysis using National Inpatient Sample (NIS) data from 2012 to 2019. Our study included hospitalized adults at least 18 years of age diagnosed with MG without an associated thymoma. We used joinpoint regression to analyze annual trends in thymectomy volume and surgical approach (minimally invasive vs trans-sternal) from 2012 to 2019. Using logistic regression models, we examined patient and hospital-level factors that may have influenced whether thymectomy was performed, such as age, sex, race, insurance payor, hospital size and teaching status, and Elixhauser Comorbidity Index. Sampling weights were applied to account for the complex survey design of NIS. Results: The total number of thymectomy procedures increased by 69.8% per year (95% CI 40.1-105.8) between 2012 and 2019. Trans-sternal thymectomies increased by 62.8% per year (95% CI 35.8-95.2) and minimally invasive thymectomies by 83.7% per year (95% CI 38.1-144.3). Thymectomies were significantly more likely to occur in 2017-2019 compared with 2012-2016 (OR 1.93, 95% CI 1.62-2.31). In a multivariable regression model, several factors decreased the odds of patients with MG having a thymectomy: older age, Black race (OR 0.62, 95% CI 0.49-0.77), female (OR 0.73, 95% CI 0.63-0.86), and higher Elixhauser Comorbidity Index. Patients in medium (OR 1.82, 95% CI 1.30-2.55) or large (OR 2.81, 95% CI 2.07-3.82) size and urban teaching hospitals (OR 6.09, 95% CI 2.65-13.97) were more likely to undergo thymectomy. Discussion: Thymectomy is being performed more frequently for non-thymomatous MG, especially after 2016 after publication of a positive phase III clinical trial. There are several disparities in thymectomy utilization that warrant further attention.

Disparities by Race in Pregnancy Care and Clinical Outcomes in Women With Multiple Sclerosis: A Diverse Multicenter Cohort

BACKGROUND AND OBJECTIVES: Racial disparities exist in both neurologic and obstetric populations, underscoring the importance of evaluating pregnancy outcomes in diverse women with multiple sclerosis (MS). The objective of this multicenter retrospective study was to compare pregnancy care and outcomes between Black and Hispanic (underrepresented) and White women with MS. METHODS: Demographic and clinical data were extracted from medical records of 9 US MS centers for women with MS/clinically isolated syndrome who delivered live births between 2010 and 2021. Sites identified at last 15 consecutive Black/Hispanic women and a matching number of White women. Socioeconomic factors, pregnancy, and MS care/outcomes were compared between groups (underrepresented and White and then Black and Hispanic) using Wilcoxon rank sum (U statistic and effect size r reported), χ2, t tests and logistic regressions as appropriate to data type. Multiple imputation by chained equation was used to account for missing data. RESULTS: Overall, 294 pregnancies resulting in live births were analyzed ( 81 Black, 67 Hispanic, and 146 White mothers). Relative to underrepresented women, White women lived in areas of higher median (interquartile range [IQR]) Child Opportunity Index (79 [45.8] vs 22 [45.8], U = 3,824, r = 0.56, p < 0.0001) and were more often employed (84.9% vs 75%, odds ratio [OR] 2.57, CI 1.46-4.50, p = 0.0008) and privately insured (93.8% vs 56.8%, OR 11.6, CI 5.5-24.5, p < 0.0001) and more received a 14-week ultrasound (98.6% vs 93.9%, OR 4.66, CI 0.99-21.96, p = 0.027). Mode of delivery was significantly different between the three groups (X2(10,294) = 20.38, p = 0.03); notably, Black women had the highest rates of emergency cesarean deliveries, and Hispanic women highest rates of uncomplicated vaginal deliveries. Babies born to underrepresented women had lower median (IQR) birthweights than babies born to White women (3,198 g [435.3 g] vs 3,275 g [412.5 g], U = 9,255, r = 0.12, p = 0.04) and shorter median (IQR) breastfeeding duration (4.5 [3.3] vs 6.0 [4.2] months, U = 8,184, r = 0.21, p = 0.003). While underrepresented women were younger than White women (mean [SD] 30.9 [4.8] vs 33.8 [4.0], t = 1.97, CI 1.96-3.98, p < 0.0001), their median (Q1-Q3, IQR) Expanded Disability Status Scale was higher (1.5 [1-2.5, 1.5] vs 1 [0-1.5, 1.5], U = 7,260, r = 0.29, p < 0.0001) before pregnancy. Finally, medical records were missing more key data for Black women (19.7% missing vs 8.9% missing, OR 2.54, CI 1.25-5.06, p = 0.008). DISCUSSION: In this geographically diverse multicenter cohort, underrepresented women entered pregnancy with higher disability and fewer health care resources. Pregnancy represents a pivotal window where structural factors affect maternal and fetal health and neurologic trajectories; it is a critical period to optimize care and health outcomes.

Relation of CMV and brain atrophy to trajectories of immunosenescence in diverse populations.

Immunosenescence (ISC), the aging of the immune system, has largely been studied in populations of European descent. Here, circulating immune cell cytometric data from African-American, Hispanic, and non-Hispanic White participants were generated. Known and novel age effects were identified using either a meta-analysis approach or a parallel genetic approach. Most results are consistent across the three populations, but some cell populations display evidence of heterogeneity, such as a PD-L1 + CD56 + NK cell subset. The study estimated "Immunological Age" (IA) during physiologic aging. While we found no relation of IA to Multiple Sclerosis, IA is associated with entorhinal cortex atrophy, a presymptomatic feature of Alzheimer's disease, linking neurodegeneration and peripheral immunity. ISC trajectories were also inferred, highlighting age, CMV status, and genetic ancestry as key influences. Our assessment offers reference ISC trajectories for personalization of assessments of immune function over the life course in diverse populations.

Severe Neuroinvasive West Nile Virus in Association With Anti-CD20 Monotherapy for Multiple Sclerosis.

OBJECTIVES: The objective of this study was to report on the development of neuroinvasive West Nile virus (WNV) infection in the context of anti-CD20 monotherapy for multiple sclerosis (MS). METHODS: This is a case series study. RESULTS: In 2021-2022, we observed 4 cases of neuroinvasive WNV infection in our patient population of 2009 patients with MS on ocrelizumab, compared with a total of 46 cases of neuroinvasive WNV infection reported in Pennsylvania and 40 in New Jersey. Odds were 258 times that of the general population (95% confidence interval 97-691), χ2 p < 0.0001). All were women aged 41-61 years with variable disease duration, level of disability, and duration of anti-CD20 therapy. All presented in summer/early fall with fever, headache, and encephalopathy consistent with meningoencephalitis. Three patients had acute cerebellitis. Two had anterior nerve root involvement progressing to quadriparesis, and 1 developed refractory nonconvulsive status epilepticus. All required intubation and experienced significant morbidity. All had CSF pleocytosis. Two patients were WNV IgM positive in both the serum and CSF, 1 patient had positive serum IgM and CSF metagenomic next-generation sequencing (mNGS), while 1 had positive CSF mNGS with negative serum and CSF antibodies. DISCUSSION: Neuroinvasive WNV infection can develop with anti-CD20 monotherapy in the absence of additional immunosuppression. WNV serologies may be negative in the setting of anti-CD20 treatment; in the appropriate clinical context, one should consider direct detection methods such as PCR or mNGS-based testing.

Cross-talk between B cells, microglia and macrophages, and implications to central nervous system compartmentalized inflammation and progressive multiple sclerosis.

BACKGROUND: B cells can be enriched within meningeal immune-cell aggregates of multiple sclerosis (MS) patients, adjacent to subpial cortical demyelinating lesions now recognized as important contributors to progressive disease. This subpial demyelination is notable for a 'surface-in' gradient of neuronal loss and microglial activation, potentially reflecting the effects of soluble factors secreted into the CSF. We previously demonstrated that MS B-cell secreted products are toxic to oligodendrocytes and neurons. The potential for B-cell-myeloid cell interactions to propagate progressive MS is of considerable interest. METHODS: Secreted products of MS-implicated pro-inflammatory effector B cells or IL-10-expressing B cells with regulatory potential were applied to human brain-derived microglia or monocyte-derived macrophages, with subsequent assessment of myeloid phenotype and function through measurement of their expression of pro-inflammatory, anti-inflammatory and homeostatic/quiescent molecules, and phagocytosis (using flow cytometry, ELISA and fluorescently-labeled myelin). Effects of secreted products of differentially activated microglia on B-cell survival and activation were further studied. FINDINGS: Secreted products of MS-implicated pro-inflammatory B cells (but not IL-10 expressing B cells) substantially induce pro-inflammatory cytokine (IL-12, IL-6, TNFα) expression by both human microglia and macrophage (in a GM-CSF dependent manner), while down-regulating their expression of IL-10 and of quiescence-associated molecules, and suppressing their myelin phagocytosis. In contrast, secreted products of IL-10 expressing B cells upregulate both human microglia and macrophage expression of quiescence-associated molecules and enhance their myelin phagocytosis. Secreted factors from pro-inflammatory microglia enhance B-cell activation. INTERPRETATION: Potential cross-talk between disease-relevant human B-cell subsets and both resident CNS microglia and infiltrating macrophages may propagate CNS-compartmentalized inflammation and injury associated with MS disease progression. These interaction represents an attractive therapeutic target for agents such as Bruton's tyrosine kinase inhibitors (BTKi) that modulate responses of both B cells and myeloid cells. FUNDING: Stated in Acknowledgments section of manuscript.

Abnormal B-Cell and Tfh-Cell Profiles in Patients With Parkinson Disease: A Cross-sectional Study.

BACKGROUND AND OBJECTIVES: There has been growing interest in potential roles of the immune system in the pathogenesis of Parkinson disease (PD). The aim of the current study was to comprehensively characterize phenotypic and functional profiles of circulating immune cells in patients with PD vs controls. METHODS: Peripheral blood was collected from patients with PD and age- and sex-matched neurologically normal controls (NCs) in 2 independent cohorts (discovery and validation). Comprehensive multicolor flow cytometry was performed on whole blood leukocytes and peripheral blood mononuclear cells to characterize different immune subsets and their ex vivo responses. RESULTS: The discovery cohort included 17 NCs and 12 participants with PD, and the validation cohort included 18 NCs and 18 participants with PD. Among major immune cell types, B cells appeared to be preferentially affected in PD. Proliferating B cell counts were decreased in patients with PD compared with controls. Proportions of B-cell subsets with regulatory capacity such as transitional B cells were preferentially reduced in the patients with PD, whereas proportions of proinflammatory cytokine-producing B cells increased, resulting in a proinflammatory shift of their B-cell functional cytokine responses. Unsupervised principal component analysis revealed increased expression of TNFα and GM-CSF by both B cells and T cells of patients with PD. In addition, levels of follicular T cells, an important B-cell helper T-cell population, decreased in the patients with PD, correlating with their B-cell abnormality. DISCUSSION: Our findings define a novel signature of peripheral immune cells and implicate aberrant Tfh:B-cell interactions in patients with PD.

Immune aging in multiple sclerosis is characterized by abnormal CD4 T cell activation and increased frequencies of cytotoxic CD4 T cells with advancing age.

BACKGROUND: Immunosenescence (ISC) describes age-related changes in immune-system composition and function. Multiple sclerosis (MS) is a lifelong inflammatory condition involving effector and regulatory T-cell imbalance, yet little is known about T-cell ISC in MS. We examined age-associated changes in circulating T cells in MS compared to normal controls (NC). METHODS: Forty untreated MS (Mean Age 43·3, Range 18-72) and 49 NC (Mean Age 48·6, Range 20-84) without inflammatory conditions were included in cross-sectional design. T-cell subsets were phenotypically and functionally characterized using validated multiparametric flow cytometry. Their aging trajectories, and differences between MS and NC, were determined using linear mixed-effects models. FINDINGS: MS patients demonstrated early and persistent redistribution of naïve and memory CD4 T-cell compartments. While most CD4 and CD8 T-cell aging trajectories were similar between groups, MS patients exhibited abnormal age-associated increases of activated (HLA-DR+CD38+; (P = 0·013) and cytotoxic CD4 T cells, particularly in patients >60 (EOMES: P < 0·001). Aging MS patients also failed to upregulate CTLA-4 expression on both CD4 (P = 0·014) and CD8 (P = 0·009) T cells, coupled with abnormal age-associated increases in frequencies of B cells expressing costimulatory molecules. INTERPRETATION: While many aspects of T-cell aging in MS are conserved, the older MS patients harbour abnormally increased frequencies of CD4 T cells with activated and cytotoxic effector profiles. Age-related decreased expression of T-cell co-inhibitory receptor CTLA-4, and increased B-cell costimulatory molecule expression, may provide a mechanism that drives aberrant activation of effector CD4 T cells that have been implicated in progressive disease. FUNDING: Stated in Acknowledgements section of manuscript.

Self- and Partner-Reported Subjective Memory Complaints: Association with Objective Cognitive Impairment and Risk of Decline.

Background: Episodic memory decline is a hallmark of Alzheimer's disease (AD). Subjective memory complaints (SMCs) may represent one of the earliest signs of impending cognitive decline. The degree to which self- or partner-reported SMCs predict cognitive change remains unclear. Objective: We aimed to evaluate the relationship between self- and partner-reported SMCs, objective cognitive performance, AD biomarkers, and risk of future decline in a well-characterized longitudinal memory center cohort. We also evaluated whether study partner characteristics influence reports of SMCs. Methods: 758 participants and 690 study partners were recruited from the Penn Alzheimer's Disease Research Center Clinical Core. Participants included those with Normal Cognition, Mild Cognitive Impairment, and AD. SMCs were measured using the Prospective and Retrospective Memory Questionnaire (PRMQ), and were evaluated for their association with cognition, genetic, plasma, and neuroimaging biomarkers of AD, cognitive and functional decline, and diagnostic progression over an average of four years. Results: We found that partner-reported SMCs were more consistent with cognitive test performance and increasing symptom severity than self-reported SMCs. Partner-reported SMCs showed stronger correlations with AD-associated brain atrophy, plasma biomarkers of neurodegeneration, and longitudinal cognitive and functional decline. A 10-point increase on baseline PRMQ increased the annual risk of diagnostic progression by approximately 70%. Study partner demographics and relationship to participants influenced reports of SMCs in AD participants only. Conclusion: Partner-reported SMCs, using the PRMQ, have a stronger relationship with the neuroanatomic and cognitive changes associated with AD than patient-reported SMCs. Further work is needed to evaluate whether SMCs could be used to screen for future decline.

Anemia in a young Guinean male.

The etiology of anemia in adults is often multifactorial. This case highlights an uncommon combination of causes of anemia and the importance of a diagnostic workup guided by a patient's unique history, risk factors, and laboratory findings.

Multisystem Inflammation and Organ Dysfunction After BNT162b2 Messenger RNA Coronavirus Disease 2019 Vaccination.

The U.S. Food and Drug Administration has to date granted approval or emergency use authorization to three vaccines against severe acute respiratory syndrome coronavirus 2 and coronavirus disease 2019. In clinical trials and real-use observational studies, the Pfizer-BioNTech BNT162b2 messenger RNA coronavirus disease 2019 vaccine, as well as the Moderna mRNA-1273 messenger RNA coronavirus disease 2019 vaccine, have demonstrated high efficacy and few adverse events. CASE SUMMARY: A 20-year-old male college student in good health developed tinnitus and hematuria shortly after vaccination and progressed swiftly to a syndrome of: systemic inflammation; acute kidney injury requiring hemodialysis; acute, bilateral, complete sensorineural hearing loss; radiographic evidence of acute multifocal ischemic strokes; pericardial effusion complicated by tamponade physiology requiring pericardial evacuation; pleural effusions requiring evacuation; and systemic capillary leak. An extensive clinical and research investigation, including cytokine analysis, whole blood cytometry by time of flight, and whole exome sequencing, did not reveal a definitive explanatory mechanism. CONCLUSION: While the overall safety profile of the BNT162b2 coronavirus disease 2019 vaccine remains excellent for the general population, rare serious events have been reported. In this report, we describe a case of multisystem inflammation and organ dysfunction of unknown mechanism beginning shortly after administration of the first dose of BNT162b2 coronavirus disease 2019 vaccine in a previously healthy recipient.

Neurology trial registrations on ClinicalTrials.gov between 2007 and 2018: A cross-sectional analysis of characteristics, early discontinuation, and results reporting.

BACKGROUND: Increasing neurological disease burden and advancing treatment options require clinical trials to expand the evidence base of clinical care. We aimed to characterize neurology clinical trials registered between October 2007 and April 2018 and identify features associated with early discontinuation and results reporting. METHODS: We compared 16,994 neurology (9.4%) and 163,714 non-neurology comparison trials registered to ClinicalTrials.gov. Trials therapeutic focus within neurology was assigned via combination programmatic and manual review. We performed descriptive analyses of trial characteristics, cox regression of early discontinuation, and multivariable logistic regression for results reporting within 3 years of completion. RESULTS: Most neurology trials were academic-funded (58.5%) followed by industry (31.9%) and US-government (9.6%). Neurology trials focused more on treatment than prevention compared to non-neurology studies. Of neurology trials, 11.3% discontinued early, and 32.2% of completed trials reported results by April 30, 2018. In multivariable analysis accounting for time-to-event, neurology trials were at lower risk of discontinuation than non-neurology trials (adjusted hazard 0.83, p < 0.0001). Both academic and government-funded trials had greater risk of discontinuation than industry (adjusted hazard 0.57 and 0.46, respectively). Among completed trials, government-funded studies (adjusted odds ratio 2.12, p < 0.0001) had highest odds of results reporting while academic trials reported less (adjusted odds ratio 0.51, p < 0.0001). CONCLUSIONS: Funding source is associated with trial characteristics and outcomes in neurology. Improvements in trial completion and timely dissemination of results remain urgent goals for the field.

Effects of IL-34 on Macrophage Immunological Profile in Response to Alzheimer's-Related Aß42 Assemblies.

Interleukin-34 (IL-34) is a recently discovered cytokine that acts as a second ligand of the colony stimulating factor 1 receptor (CSF1R) in addition to macrophage colony-stimulating factor (M-CSF). Similar to M-CSF, IL-34 also stimulates bone marrow (BM)-derived monocyte survival and differentiation into macrophages. Growing evidence suggests that peripheral BM-derived monocyte/macrophages (BMMO) play a key role in the physiological clearance of cerebral amyloid ß-protein (Aß). Aß42 forms are especially neurotoxic and highly associated with Alzheimer's disease (AD). As a ligand of CSF1R, IL-34 may be relevant to innate immune responses in AD. To investigate how IL-34 affects macrophage phenotype in response to structurally defined and stabilized Aß42 oligomers and preformed fibrils, we characterized murine BMMO cultured in media containing M-CSF, IL-34, or regimens involving both cytokines. We found that the immunological profile and activation phenotype of IL-34-stimulated BMMO differed significantly from those cultured with M-CSF alone. Specifically, macrophage uptake of fibrillar or oligomeric Aß42 was markedly reduced following exposure to IL-34 compared to M-CSF. Surface expression of type B scavenger receptor CD36, known to facilitate Aß recognition and uptake, was modified following treatment with IL-34. Similarly, IL-34 macrophages expressed lower levels of proteins involved in both Aß uptake (triggering receptor expressed on myeloid cells 2, TREM2) as well as Aß-degradation (matrix metallopeptidase 9, MMP-9). Interestingly, intracellular compartmentalization of Aß visualized by staining of early endosome antigen 1 (EEA1) was not affected by IL-34. Macrophage characteristics associated with an anti-inflammatory and pro-wound healing phenotype, including processes length and morphology, were also quantified, and macrophages stimulated with IL-34 alone displayed less process elongation in response to Aß42 compared to those cultured with M-CSF. Further, monocytes treated with IL-34 alone yielded fewer mature macrophages than those treated with M-CSF alone or in combination with IL-34. Our data indicate that IL-34 impairs monocyte differentiation into macrophages and reduces their ability to uptake pathological forms of Aß. Given the critical role of macrophage-mediated Aß clearance in both murine models and patients with AD, future work should investigate the therapeutic potential of modulating IL-34 in vivo to increase macrophage-mediated Aß clearance and prevent disease development.

Can agrin cerebrospinal fluid concentration be used as an early biomarker for Alzheimer's disease?

The need for effective treatments halting Alzheimer's disease (AD) urges the discovery of the earliest possible biomarkers. Agrin is increased in the early stages of AD and is involved in amyloid-ß (Aß) fibrillation and synaptogenesis. We investigated the potential of agrin as an early AD cerebrospinal fluid (CSF) biomarker. We analyzed the agrin CSF concentration in nondemented controls (n = 20) and those with mild (n = 20) and severe (n = 20) AD. The levels of agrin CSF were not significantly divergent among the different patient groups and did not correlate with the concentration of Aß42, total tau, phosphorylated tau, or the Mini Mental State Examination scores. However, agrin strongly correlated with age in those with dementia. The results indicate that agrin cannot be used as an early AD CSF biomarker using the current immunoassay. However, our population was relatively young; thus, the correlation between agrin and age suggests that stronger differences in agrin concentrations might be found in older groups with more heterogeneous AD pathologic features.