Our laboratory is interested in the role that B cells may play in the pathogenesis of Multiple Sclerosis.   Multiple Sclerosis is an inflammatory, demyelinating disease of the Central Nervous System (CNS), which likely involves an autoimmune response directed against self-myelin associated antigens.   There are several pieces of evidence that suggest that B cells are involved in the pathogenesis of MS.  We have several projects in the lab that are designed to test this hypothesis with the following questions:

Compare the spinal fluid and peripheral blood B cell antibody repertoires of MS patients and normal donors.

This is done using a novel single cell PCR technique in which antibody rearrangements are amplified from genomic DNA of single B cells using a multiplex nested PCR approach.   We hypothesize that since MS is a disease of the Central Nervous System, there will be very few (if any) differences in the peripheral blood B cell antibody repertoires of MS patients and normal donors, but that the spinal fluid B cell antibody repertoires will be vastly different.  This is, in fact what we have observed, and the differences in antibody repertoire usage are largely because the B cells in the spinal fluid of MS patients have undergone extensive clonal expansion.  This data suggests that B cells in the spinal fluid of MS patients are reactive to antigens present in the Central Nervous System.

  Analysis of CSF B cells from Multiple Sclerosis Patients (PDF File)

Determine if clonally expanded B cells in the spinal fluid of MS patients are reactive to antigens present in the Central Nervous System. 

In order to test the antigenic specificity of these clonally expanded B cells from MS patients, Fab fragments of both the heavy and light chains of the antibodies from each candidate B cell clone from the spinal fluid of MS patients are expressed and tested for their binding capacity to myelin associated proteins, control antigens, and other antigens with possible roles in the pathogenesis of MS.

Determine whether B cell clones from these MS patients persist over time.

Spinal fluid and peripheral blood from MS patients who demonstrated B cell clonal expansion in the spinal fluid  will be sampled again 1,2 and 3 years after their initial spinal fluid sampling.  Standard PCR will be performed on the CSF and peripheral blood using primers specific to the CDR3 regions of the clones.  This will allow us to track the persistence of these clones in the CSF of these previously characterized MS patients, and determine whether we can detect these clones in their peripheral blood.

Determine whether a B cell depleting drug called Rituximab has an effect on the spinal fluid B cell repertoires of MS patients. 

Three samplings of CSF and PB will be obtained to define the B cell antibody repertoires by single cell PCR.   The first sampling of CSF and PB will establish the “baseline” B cell antibody repertoire, the second will define the residual B cell antibody repertoire immediately following Rituximab therapy, and the third will define the reconstituted B cell antibody repertoire 1 year after Rituximab therapy has been completed. We hypothesize that the post-Rituximab B cell antibody repertoires will be altered in comparison to the pre-Rituximab B cell antibody repertoires.  Understanding the effect Rituximab has (if any) on the CSF B cell population will likely have a profound effect on the next generation of B cell depleting therapies in the treatment of both established and suspected B cell mediated autoimmune diseases of the CNS, such as PPMS.

Effect of Rituximab on Patients with Primary Progressive Multiple Sclerosis (PDF File)