Blood cell ratio may be biomarker of NMOSD disability: Study
Platelet-to-lymphocyte ratio, others seen as potential targets for interventions
The platelet-to-lymphocyte ratio, a blood inflammatory marker that can be calculated based on the results of a simple blood test, may be used as a biomarker of disability severity in people with neuromyelitis optica spectrum disorder (NMOSD), a small study showed.
Researchers identified four other ratios, calculated based on the amount of certain proteins in the cerebrospinal fluid (CSF) — the liquid around the brain and spinal cord — relative to blood, as biomarkers of disability severity in NMOSD.
“The discovery of these disability-related biomarkers in NMOSD opens up possibilities for providing more effective interventions to reduce the severity of disability and improve outcomes,” the researchers wrote.
The study, “Acute neuromyelitis optica spectrum disorder patients’ clinical analysis of disability-related biomarkers,” was published in BMC Neurology.
NMOSD is a rare autoimmune disease marked by damaging inflammation in the eye nerves (optic neuritis) and spinal cord (transverse myelitis). This can lead to a range of symptoms, from loss of eyesight to difficulty walking.
Blood-brain barrier disruption
A disruption in the blood-brain barrier, a highly selective membrane that prevents potentially harmful microbes and molecules in circulation from entering the brain and spinal cord, is thought to contribute to the inflammatory attacks in NMOSD.
Previous studies showed a strong association between the degree of blood-brain barrier disruption and disability severity in NMOSD.
“However, the relationship between blood inflammatory markers and NMOSD disability severity remains unclear,” the researchers wrote. “Further exploration of the correlation between [blood] inflammatory biomarker levels, blood-brain barrier disruption, and disability severity in NMOSD is essential,” as it “could offer improved diagnostic and treatment approaches for NMOSD patients.”
The team of researchers in China sampled blood and CSF from 41 NMOSD patients and 41 healthy people. Both groups had a mean age of about 41, and the majority were women.
Some ratios calculated based on the numbers of certain blood cells — the platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio, and monocyte-to-lymphocyte ratio — were significantly higher in patients than in healthy controls.
Platelets, lymphocytes, neutrophils, and monocytes play important roles in the body’s inflammatory response. Neutrophils and monocytes are the first to be recruited to sites of inflammation, while platelets form clusters with lymphocytes in inflamed tissues, prolonging the response.
Patients were divided into two groups based on their disability severity, as assessed with the standard Expanded Disability Status Scale (EDSS). A total of 21 patients had mild to moderate disability (EDSS score below 4), and the remaining 20 patients had severe disability (EDSS score of 4 or higher).
The two groups had about the same proportion of men (61.9% vs. 60%) and average age (33.3 vs. 37.4). When the researchers compared them, they found that the PLR was significantly higher in patients with severe disability than in those with mild to moderate disability.
The severe disability group also showed significantly higher values in four other ratios, calculated based on the amount of albumin (QAlb), immunoglobulin G (QIgG), immunoglobulin A (QIgA), and immunoglobulin M (QIgM) in the CSF relative to blood. Albumin is a large protein found in the blood, while immunoglobulins G, A, and M are types of antibodies, which are involved in immune and inflammatory responses.
Higher PLR, QAlb, QIgG, QIgA, and QIgM were each significantly associated with higher EDSS scores, reflecting more severe disability.
Further statistical analyses showed that these five ratios were able to distinguish between patients with severe disability and those with less severe disability with a high degree of accuracy.
However, on analyses adjusted for potential influencing factors, PLR was the only ratio found to be an “independent indicator of NMOSD severity,” the team wrote.
While the findings point to PLR, QAlb, QIgG, QIgA, and QIgM as biomarkers for understanding NMOSD severity, “it is noteworthy that this study revealed the potential of PLR as an independent indicator for evaluating the severity of NMOSD,” the researchers wrote.
“These findings provide new insights and methods for the clinical assessment of NMOSD disability, aiding in a more precise evaluation of patient conditions and prognosis,” the researchers concluded. “This could offer improved diagnostic and treatment approaches for NMOSD patients.”
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