Abstract
Several viruses have the capacity to cause serious infections of the nervous system in patients who are immunosuppressed. Individuals may be immunosuppressed because of primary inherited immunodeficiency, secondary immunodeficiency due to particular diseases such as malignancy, administration of immunosuppressant drugs or organ or bone marrow transplantation. The viruses capable of such opportunistic infection of the nervous system include herpes simplex virus (HSV), Varicella-Zoster virus (VZV), Cytomegalovirus (CMV), Epstein –Barr virus (EBV), Human Herpes virus type 6 (HHV-6), JC virus (JCV), enterovirus, measles virus and Covid-19. In most cases it seems likely that immunological defence mechanisms in the immunosuppressed are deficient which creates a suitable environment for certain viruses to become opportunistic in the nervous and other systems. Further research is required both to understand these opportunistic mechanisms in more detail and also to determine how many virus infections are modified by specific inborn errors of immunological responses.
Highlights
An individual may become immunocompromised as a result of multiple factors. These include the administration of immunosuppressant drugs given for various medical conditions, an underlying disease such as Human Immunodeficiency Virus (HIV) infection or malignancy such as lymphoma which affects the immune system producing secondary immunodeficiency, various primary immunodeficiency syndromes such as severe combined immunodeficiency (SCID) with defects in T cells, B cells, and NK cells [1], or from organ or bone marrow transplantation
In the case of Varicella Zoster (VZV) infection, following primary infection the virus becomes latent in neurons in peripheral ganglia [4]
While herpes simplex virus (HSV)-1 is classically associated with herpes simplex encephalitis (HSE) [10], HSV-2 accounts for about 10% of cases of HSE and when it does so it is typically associated with immunosuppression [11] so is of greater relevance to the current overview
Summary
An individual may become immunocompromised as a result of multiple factors These include the administration of immunosuppressant drugs given for various medical conditions, an underlying disease such as Human Immunodeficiency Virus (HIV) infection or malignancy such as lymphoma which affects the immune system producing secondary immunodeficiency, various primary immunodeficiency syndromes such as severe combined immunodeficiency (SCID) with defects in T cells, B cells, and NK cells [1], or from organ or bone marrow transplantation. In the case of Varicella Zoster (VZV) infection, following primary infection (chicken pox) the virus becomes latent in neurons in peripheral ganglia [4] It may reactivate causing herpes zoster (shingles), more commonly in conditions of immunosuppression, for instance in the elderly who have impaired cell mediated immunity (CMI) to VZV [5, 6]. In many cases there is included an indication of the Class of Evidence and Level of Recommendation for a therapeutic intervention or an investigative procedure, and these are based on previously published criteria which are used for official European Academy of Neurology guidelines [7, 8, 9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
