The auto-reactive profile of B cells from early MS patients

Abstract

Abstract My lab’s recent work has led to the discovery that antibodies expressed by memory B cells in the cerebrospinal fluid (CSF) of patients with Multiple Sclerosis recognize neurons and astrocytes in the brain. Genetic analysis further revealed that only certain heavy chain genes accommodate binding to these brain targets, and that memory B cells from control cohorts rarely express these antibody genes. In fact, in a recent clinical trial, we demonstrated that the prevalence of these antibody genes expressed by memory B cells in the CSF support identification of patients who either have MS or will develop MS in the future with 89–94% accuracy. This Antibody Gene Signature (AGS) is a novel biomarker that heralds the advent of antibody genetics as a means to support categorization of patients early in their disease course. Our goal for this project was to determine whether antibodies expressed by activated memory B cells that have initiated antibody production (called “plasmablasts”) in the peripheral blood of MS patients also recognize neurons and astrocytes. We cloned and expressed more than 50 antibodies expressed by peripheral plasmablasts of early MS patients and control cohorts. We found that antibodies expressed by peripheral plasmablasts from patients who develop MS bind to neurons and astrocytes in the brain. Those plasmablasts that did not express antibody heavy chains associated with the AGS did not bind to brain targets. Interestingly, only those patients in our cohort who have an elevated frequency of peripheral plasmablasts continue to accumulate brain MRI activity. It is possible that brain-reactive peripheral plasmablasts contribute to the brain damage associated with MS.