Changes in the numbers of immune cells in the blood are associated with the progression of ALS, a study reports.
Keeping tabs on the numbers could help doctors track the disease and researchers identify targets to develop treatments around, it said.
The study, “Correlation of Peripheral Immunity With Rapid Amyotrophic Lateral Sclerosis Progression,” was published in JAMA Neurology.
Researchers recruited 119 amyotrophic lateral sclerosis patients and 35 controls for the study. Patients’ average age was 61 years old. Fifty were women.
A key finding was that the number of white blood cells was higher in ALS patients than in controls.
Researchers then compared the number of different kinds of immune cells in some patients with their physical functioning scores over time. Such scores decline as the disease evolves. The functioning index the team used was the Revised ALS Functional Rating Scale, or ALSFRS-R.
Higher numbers of all white blood cells were associated with a rapid disease in the progression of ALS. The number of T-cells — one kind of white blood cell — dropped slowly as the disease progressed. Increases in the number of another kind of white blood cell, a neutrophil, were associated with the disease’s progression, however.
Further analysis showed that lower T-cell and neutrophil numbers early in the disease were associated with rapid progression of the disease, compared with controls.
Researchers also discovered that numbers of a cell called a CD14−CD16− myeloid cell peaked, then fell back to normal during the course of the disease. The cell gets its name from lack of CD14 and CD16 protein markers on its surface.
While the researchers suspect that the changes they saw in white blood cell numbers play a role in the progression of ALS, the study did not prove this. It simply documented changes in the numbers of different kinds of white blood cells. One reason the team believes there is a link between white cell numbers and progression of ALS is because of the brain damage that immune activation often causes.
“Although the data are consistent with previous clinical reports and mouse models of ALS, changes in peripheral immunity may be a consequence rather than a cause of disease,” they wrote.
They concluded that changes in the immune system may be part of the typical behavior of ALS.
“In this study, we demonstrate that changes in the number of immune cells, particularly neutrophils and CD4 T-cells, are correlated with disease progression,” the team wrote. “Other cell populations, such as NK cells and a population of CD11b+CD14−CD16− myeloid cells, may also play a role.” This means that “further investigations are needed in these areas.”