DALLAS – Patients with multiple sclerosis (MS) have elevated levels of specific clusters of cerebrospinal fluid (CSF) biomarkers related to astrocytes and microglia that correlated with disease severity in a blinded analysis of more than 1,000 proteins from the CSF of more than 400 patients with neuroimmunologic disease and healthy volunteers.
Previous studies have indicated that aberrant activation of astrocytes and microglia underlies disability progression in older patients with MS, but researchers have lacked biomarkers of these processes in living subjects. In a presentation at a meeting held by the Americas Committee for Treatment and Research in Multiple Sclerosis, Ruturaj R. Masvekar, PhD, described developing biomarkers of CNS cell–specific processes and examining how they relate to MS disability progression. Dr. Masvekar, a researcher at the National Institute of Allergy and Infectious Diseases, and his coinvestigators used a modified DNA aptamer assay to measure proteins in the CSF of 431 patients with neuroimmunologic diseases and healthy volunteers, followed by variable cluster analysis and in vitro modeling to define 64 clusters of CSF biomarkers that relate to CNS cell types.
The study included 42 healthy donors, 20 patients with clinically isolated syndrome, 57 patients with noninflammatory neurologic disorders, 127 patients with relapsing-remitting MS, 72 patients with secondary progressive MS, and 113 patients with primary progressive MS. In a training cohort of 217 participants, the researchers assessed how biomarkers differed between the diagnostic categories. The researchers then validated the results in an independent cohort of 214 participants.
One astrocyte-related cluster (MMP7, SERPINA3, GZMA, and CLIC1) and one microglia-related cluster (DSG2 and TNFRSF25) was significantly elevated in all MS subgroups, compared with healthy controls and patients with noninflammatory neurologic disorders.
In addition, these clusters “significantly correlated with clinical measures of disability, CNS tissue destruction, and MS severity,” Dr. Masvekar said.
The microglial cluster was significantly elevated in all MS subgroups, whereas neuronal endothelial, astrocytic, and oligodendroglial biomarker clusters were elevated only in patients with progressive MS.
“Microglial activation is present in all stages of MS, while toxic astrogliosis increases with MS duration, concomitantly with neuronal and oligodendroglial degeneration,” Dr. Masvekar said. “Microglial activation and toxic astrogliosis likely partake in CNS tissue destruction and enhance MS severity.”
This study, which was recently published in Multiple Sclerosis and Related Disorders (), was supported by the intramural research program at NIAID.
SOURCE: Masvekar RR et al. ACTRIMS Forum 2019, Abstract 281.