Researchers at Trinity College Dublin have discovered that microglia – the main immune cells of the brain – play a critical role in maintaining the stability of neuronal networks in Alzheimer’s disease. Crucially, this suggests treatments that indiscriminately suppress these cells could be counterproductive.

Microglia, by driving brain inflammation, are generally considered to accelerate Alzheimer’s disease. But the study, published in leading neurology journal Brain, found that reducing the number and activity of these cells unexpectedly worsened abnormal electrical activity in the brain and increased seizure-like events. 

On July 26–30, the greatest minds in clinical laboratory medicine will converge in Anaheim, California for ADLM 2026. Convened by the Association for Diagnostics & Laboratory Medicine (ADLM), this year’s meeting will be headlined by a legendary figure in diabetes care, a physician to astronauts, an Alzheimer’s and Down syndrome expert, a doctor working to broaden cervical cancer screening, and a scientist uncovering new biomarkers for blood cancers.

About The Study: A study in JAMA presented Wednesday, July 15, at the annual Alzheimer’s Association International Conference reports that a blood test measuring phosphorylated tau 217 (P‑tau217) in plasma can help estimate an individual’s risk of developing cognitive impairment over the following 2, 5, and 10 years.

Across six cohorts, higher p-tau217 levels were consistently associated with increased risk of progression to cognitive impairment in cognitively unimpaired older adults, and the association remained significant after adjustment for amyloid PET.

The findings support P‑tau217 as a marker linked to amyloid and tau-related disease processes. If ongoing secondary prevention trials demonstrate that early intervention can delay or prevent cognitive decline, blood‑based biomarkers like P‑tau217 could help identify individuals most likely to benefit, authors note.

However, current Alzheimer’s Association clinical practice guidelines recommend against testing cognitively unimpaired older adults outside research studies or clinical trials.

Authors emphasize that the risk estimates are based on selected research cohorts, with greater confidence in 5‑year than 10‑year projections, and that current models do not fully account for vascular comorbidities or competing risk of death; additionally, P-tau217 may not fully reflect non-Alzheimer contributors to cognitive impairment, such as vascular or other neurodegenerative processes.

A blood test for the biomarker phosphorylated tau 217 (p-tau217) recently received federal clearance, but questions have emerged around the extent to which such tests can accurately predict whether a cognitively healthy individual will go on to develop cognitive impairment—a key symptom of Alzheimer’s disease. A new, international study involving researchers across three continents and led by experts from the Mass General Brigham Neuroscience Institute sheds new light on the prognostic value of such tests. The study found that cognitively unimpaired individuals with very high levels of the biomarker had a 38% absolute risk of developing cognitive impairment over the next five years—and higher risk over the next 10 years. Results are presented at the Alzheimer’s Association International Conference and simultaneously published in JAMA.

The University of Cincinnati and UC Health are launching the Center for Alzheimer's and Neurodegenerative Diseases Research (CANDR) to advance dementia research, clinical care and brain health education.