Oligoclonal M bands unveil occult inflammation in multiple sclerosis

• Published in: Multiple sclerosis and related disorders Vol. 68; p. 104118
• Main Authors: Casanova, Bonaventura, Castillo, Jessica, Quintanilla-Bordás, Carlos, Sanz, María T., Fernández-Velasco, Jose I, Alcalá, Carmen, Carratalá, Sara, Gasque, Raquel, Rubio, Almudena, Cubas, Laura, Villar, Luisa María, Pérez-Miralles, Francisco
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2022
• Subjects: Autoantigens; Biomarkers; Brain - diagnostic imaging; Brain - pathology; Humans; Inflammation - diagnostic imaging; Magnetic Resonance Imaging; Multiple Sclerosis - complications; Multiple Sclerosis - diagnostic imaging; Oligoclonal Bands - cerebrospinal fluid
• ISSN: 2211-0348; 2211-0356
• DOI: 10.1016/j.msard.2022.104118

Recent works demonstrate that patients with multiple sclerosis (pwMS) and oligoclonal M bands (OCMB) in cerebrospinal fluid (CSF) are at higher risk of conversion to secondary progressive course, suggesting a distinct pathophysiology pathway in these patients. To analyze the relationship of serum neurofilament light chain (s-NFL) in absence of inflammatory activity in people with multiple sclerosis (pwMS) according to the presence of OCMB versus healthy controls (HC), and the effect of aging. Two cohorts of HC were compared to a cohort of pwMS without clinical or radiological signs of acute inflammation. Lack of inflammation was defined as the absence of relapses or gadolinium-enhancing lesions (GEL) brain in an MRI performed within three months before and after s-NFL determination. S-NFL was measured with SIMOa technology. OCMB in the cerebrospinal fluid (CSF) were analyzed with isoelectric focusing and immunoblotting. 254 people were studied: 124 healthy voluntary controls and 130 pwMS. Despite the absence of inflammatory activity, pwMS and OCMB showed higher levels of s-NFL compared to those without OCMB and HC (11.4 pg/mL, 8.9 pg/mL and 9.0 pg/mL, respectively). A positive and exponential correlation between age and s-NFL was observed, with highest increases among pwMS and OCMB in the CSF. In absence of overt inflammatory activity, pwMS and OCMB exhibit higher s-NFL levels, and a greater age-related increase. Thus, OCMB may portray an underlying inflammatory process not detected by conventional MRI studies and may explain the poorer prognosis of these patients.