The diagnostic algorithm for the demyelinating disorders of the central nervous system remains a work in progress, with the search for the ideal biomarkers ongoing. The so-called “ideal” biomarker should ensure the accurate differentiation between the most common demyelinating pathologies of the CNS and between the subtypes of the same pathology (for example, the conversion from relapsing–remitting multiple sclerosis to the secondary progressive phenotype). Advances in technology facilitated this research and in the following sections we will comprehensively review most of these, outlining the past, present, and prospects and the impact they had on both diagnosis and therapeutic approach.

Myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, and idiopathic inflammatory myopathies are among the most widely recognized autoimmune neuromuscular disorders. Although they differ in clinical presentation, shared immunopathogenic mechanisms place them at a molecular crossroads. Evidence of overlapping pathways has led to the development of targeted strategies including complement inhibition, FcRn antagonism, B-cell depletion, and the CAR-T cell approach. In this review, we analyze current knowledge regarding pathogenic mechanisms and their link to immunotherapy, extensively outlining both similarities and distinctions. We further discuss existing challenges, including diagnostic limitations and refractory disease variants, how technological advances have already addressed some of these issues, and where further progress is still needed.