Immunology of multiple sclerosis: an update

PURPOSE OF REVIEW: The immunological processes that lead to multiple sclerosis (MS) and occur during the progressive phase of the disease are manifold and still not well understood. This review summarizes new insights on this topic that were gained through recent studies with diverse scientific approaches. RECENT FINDINGS: While genetic risk clearly contributes to MS, external factors play a key role in its pathogenesis as well. Epstein-Barr virus infection correlates significantly with MS risk and seems to be a major causal factor. Even though our knowledge on the human gut microbiome and its connection to the central nervous system is far from being complete, several studies have proven that the gut-brain axis influences neuroinflammation and disease progression in MS. It has become much clearer that MS is not solely a T cell-mediated disease but is also strongly driven by B cells and pathogenic antibodies. Beyond the peripheral immune cells, glial cells and their interactions with neurons are important players contributing to disease activity and progression in MS. SUMMARY: Taken together, recent publications on immunological processes in the context of MS implicate a multitude of noncanonical mechanisms that need to be further explored regarding their interplay and contribution to the degenerative course of the disease.