For years, the "holy grail" of Alzheimer’s research has been a simple, affordable way to identify who is at risk before the first signs of forgetfulness begin. On April 22, 2026, we got our answer.
A landmark study involving nearly 400,000 patients has revealed that high levels of neutrophils—the immune system's first-responder white blood cells—relative to other immune cells can signal an increased risk of Alzheimer’s and related dementias years before clinical symptoms appear
The study, led by researchers at NYU Langone Health and the Veterans Health Administration, focused on a metric called the Neutrophil-to-Lymphocyte Ratio (NLR).
While doctors have used the NLR for years to track general infection and inflammation, this study is the first large-scale investigation to prove its predictive power for neurodegeneration. By analyzing electronic health records from a massive, diverse population, the team found that:
Perhaps the most provocative finding from the research team, led by Dr. Tianshe (Mark) He and Dr. Jaime Ramos-Cejudo, is that neutrophils might not just be "bystanders."
Evidence suggests that these immune cells can cause tissue damage at the vascular level. In Alzheimer’s pathology, neutrophils have been observed accelerating disease progression by causing inflammation in the brain’s blood vessels. If neutrophils are actively contributing to the damage, they could move from being a "warning light" to becoming a direct therapeutic target—meaning we could potentially treat the inflammation to slow or stop the disease.
| Marker | Role in the Body | Alzheimer's Connection |
| Neutrophils | Fast-acting "first responders" to inflammation/infection. | High levels correlate with vascular tissue damage and brain inflammation. |
| Lymphocytes | Targeted "special forces" (T-cells/B-cells) that manage immunity. | Lower levels relative to neutrophils indicate a stressed, imbalanced immune system. |
| NLR Score | The ratio between the two. | High NLR = Systemic Inflammation. This score serves as the "Early Warning" signal. |
The beauty of this discovery lies in its accessibility. Unlike expensive PET scans or invasive spinal taps, the NLR is calculated from a Complete Blood Count (CBC)—the most common blood test in the world.
"In the meantime, we hope the NLR can contribute to 'gateway diagnostic tools,'" said Dr. Ramos-Cejudo. By flagging high-risk individuals during routine check-ups, doctors can now prioritize those patients for in-depth testing and lifestyle interventions years earlier than previously possible.