Reader response: Neurologic complications of coronavirus infections.

I read the editorial by Dr. Nath1 with interest. One aspect of the CNS involvement in SARS-CoV-2 infection that has attracted little interest so far is the medium- or long-term consequences on patients with neurodegenerative diseases (NDD). It is known that chronic neuroinflammation has been associated with the neuropathophysiology of some NDDs such as multiple sclerosis, Parkinson disease, Alzheimer disease (AD), and others.2 In the case of AD, in the presence of proinflammatory cytokines/chemokines, the microglia loses ability to phagocytize the Aβ protein, favoring the pathogenic deposits.3 Similar evidence exists in other NDD.4 The cytokine storm of SARS-CoV-2 infection involves the activation of a neuroinflammatory cascade similar to that described in NDD.5 Furthermore, the possibility that this molecular movement may be persistent over time after acute infection is eliminated in a similar way to what occurs in the so-called “persistent inflammation-immunosuppression and catabolism syndrome.”5 Finally, we do not know whether SARS-CoV-2 may have the ability to remain latent in the CNS in a similar way as other coronaviruses do,6  increasing the possibility of sustained neuroinflammation. The repercussion on the population vulnerable to NDD is unknown but will force us to be attentive to the future of our patients.