Simultaneous Guillain-Barrè syndrome and active human herpesvirus 6 infection in the central nervous system

From Viral Infection to Autoimmune Reaction: Exploring the Link between Human Herpesvirus 6 and Autoimmune Diseases

The complexity of autoimmunity initiation has been the subject of many studies. Both genetic and environmental factors are essential in autoimmunity development. Among others, environmental factors include infectious agents. HHV-6 is a ubiquitous human pathogen with a high global prevalence. It has several properties suggestive of its contribution to autoimmunity development. HHV-6 has a broad cell tropism, the ability to establish latency with subsequent reactivation and persistence, and a range of immunomodulation capabilities. Studies have implicated HHV-6 in a plethora of autoimmune diseases-endocrine, neurological, connective tissue, and others-with some studies even proposing possible autoimmunity induction mechanisms. HHV-6 can be frequently found in autoimmunity-affected tissues and lesions; it has been found to infect autoimmune-pathology-relevant cells and influence immune responses and signaling. This review highlights some of the most well-known autoimmune conditions to which HHV-6 has been linked, like multiple sclerosis and autoimmune thyroiditis, and summarizes the data on HHV-6 involvement in autoimmunity development.

Guillain-Barré syndrome, transverse myelitis and infectious diseases

Guillain-Barré syndrome (GBS) and transverse myelitis (TM) both represent immunologically mediated polyneuropathies of major clinical importance. Both are thought to have a genetic predisposition, but as of yet no specific genetic risk loci have been clearly defined. Both are considered autoimmune, but again the etiologies remain enigmatic. Both may be induced via molecular mimicry, particularly from infectious agents and vaccines, but clearly host factor and co-founding host responses will modulate disease susceptibility and natural history. GBS is an acute inflammatory immune-mediated polyradiculoneuropathy characterized by tingling, progressive weakness, autonomic dysfunction, and pain. Immune injury specifically takes place at the myelin sheath and related Schwann-cell components in acute inflammatory demyelinating polyneuropathy, whereas in acute motor axonal neuropathy membranes on the nerve axon (the axolemma) are the primary target for immune-related injury. Outbreaks of GBS have been reported, most frequently related to Campylobacter jejuni infection, however, other agents such as Zika Virus have been strongly associated. Patients with GBS related to infections frequently produce antibodies against human peripheral nerve gangliosides. In contrast, TM is an inflammatory disorder characterized by acute or subacute motor, sensory, and autonomic spinal cord dysfunction. There is interruption of ascending and descending neuroanatomical pathways on the transverse plane of the spinal cord similar to GBS. It has been suggested to be triggered by infectious agents and molecular mimicry. In this review, we will focus on the putative role of infectious agents as triggering factors of GBS and TM.

Incidence of human herpesvirus 6 in clinical samples from Swedish patients with demyelinating diseases

BACKGROUND

Human herpesvirus 6 (HHV-6) has been reported to be associated with multiple sclerosis (MS) and Guillain-Barré syndrome (GBS).

METHODS

We analyzed cell-free HHV-6 DNA as an indication of active infection in the peripheral blood and cerebrospinal fluid (CSF) of Swedish patients with GBS, patients with chronic inflammatory demyelinating polyradiculoneuropathy, treatment-naïve patients with possible MS, interferon-β treated MS patients [with or without neutralizing antibodies (NAbs)], and control patients with headache.

RESULTS

One of 14 GBS patients and one of eight patients with chronic inflammatory demyelinating polyradiculoneuropathy were positive for HHV-6 DNA in serum. Of the 27 treatment-naïve possible MS patients, two were positive in plasma and one in CSF. HHV-6 DNA was detected in the serum of three of 79 NAb+ patients and one of 102 NAb-interferon-β treated MS patients. HHV-6 DNA could not be detected in the plasma or CSF of any of the 33 controls, although the differences were not statistically significant.

CONCLUSION

Our results do not suggest active HHV-6 infection to be a common phenomenon in any of the patient groups studied.

Simultaneous human herpesvirus 6-associated encephalitis and Guillain-Barré syndrome in a patient after matched unrelated donor haematopoietic stem cell transplantation

Viral infections are still a serious diagnostic and therapeutic problem in patients undergoing alternative donor transplants. β-Herpesviruses (especially human herpesvirus type 5, 6 and 7) are recognized pathogens in this group of patients and may cause central nervous system disease. Guillain-Barré syndrome (GBS) is a very rare complication among stem cell transplant recipients and usually has been attributed to infection. We report a case of resolving simultaneous GBS and HHV-6-associated encephalitis in a haematopoietic stem cell transplant recipient with preceding reactivation of cytomegalovirus (CMV) infection. According to our knowledge this well-documented case is probably the first report from Poland.