Viral infections, neurodegenerative & psychiatric diseases: an arduous search for clues …

Viruses & Multiple Sclerosis

Data accumulate which highlight an important role of both autoimmune inflammation and progressive neurodegeneration in the pathophysiology of multiple sclerosis (MS). Despite an obvious success in reducing the burden of symptoms during relapses of the relapsing-remitting form of the disease (RRMS[1]), the clinical suppression of inflammation has however little to no effect on the progressive phase. The progressive component is a phase that either follows the earlier stage of RRMS or is immediately present at the onset of the disease in 15% of patients (PPMS[2]). Research data demonstrate a complex interplay between immunogenetics, environment, a neurodegenerative process underlying demyelination and a persistent innate inflammatory response that seems to increase as adaptive autoimmunity seems to fade (Stys and Tsutsui 2019). Interestingly, again, viruses have been suspected to play a role in the pathophysiology of Multiple Sclerosis, and in particular the Epstein Barr virus (EBV). Past exposure to the EBV is virtually a prerequisite for developing MS, while patients with symptomatic infection (mononucleosis) carry a higher risk of MS. However, the very high prevalence EBV exposure worldwide demonstrates that this factor is necessary but not sufficient to trigger MS. Does the EBV play a causative role or does it influence the secondary autoimmune response? Is that only one of the necessary factors in the chain of development of the disease? Clearly, much remains to be done but the encouraging data with a small cohort of patients treated with an EBV specific T cell therapy call for more research in this (viral) direction.

PP

[1] Relapsing Remitting Multiple Sclerosis [featured by relapses and remissions]

[2] Primary Progressive Multiple Sclerosis [featured by a steady decline of function without relapses and remissions]

Viruses & Parkinson’s disease

Parkinson’s Disease (PD) is a neurodegenerative disease caused by ... read more