B cell expressing anti-muscle-specific kinase autoantibodies (Anti-MuSK B cell)

B cells expressing anti-muscle-specific kinase (MuSK) autoantibodies are a specialized population of pathogenic immune cells central to the development of MuSK-associated myasthenia gravis (MuSK-MG). These cells, which include short-lived plasmablasts, produce high-affinity IgG4 autoantibodies that target the first immunoglobulin-like domain of the MuSK protein at the neuromuscular junction. By binding to MuSK, these autoantibodies disrupt the essential interaction between MuSK and LRP4, preventing acetylcholine receptor clustering and causing severe muscle weakness. While conventional treatments like rituximab provide broad B-cell depletion, they often lead to generalized immunosuppression and increased infection risk. Modern therapeutic efforts are focused on the precision depletion of these specific B-cell clones using chimeric autoantibody receptor (CAAR) T cells, such as MuSK-CAART, which utilize the MuSK antigen to direct T-cell cytotoxicity exclusively toward the autoreactive B-cell receptor. This approach aims to eliminate the source of pathogenic antibodies and induce long-term disease remission without compromising the patient's overall humoral immunity.

Other names

MuSK-specific B cellAnti-MuSK B lymphocyteAnti-muscle-specific kinase B cellMuSK-reactive B cellMuSK-specific plasmablast

Precision depletion of B cells expressing anti-MuSK autoantibodies via Chimeric Autoantibody Receptor (CAAR) T cells; non-selective depletion via anti-CD20 or anti-CD19 monoclonal antibodies; and reduction of circulating autoantibody levels through FcRn inhibition or B-cell survival factor antagonism.