Coxsackie B virus

Coxsackie B (also written coxsackievirus B) is a group of six types of enterovirus, causing symptoms ranging from gastrointestinal distress to pericarditis and myocarditis.

Symptoms
Symptoms of infection with viruses in the Coxsackie B grouping include fever, headache, sore throat, gastrointestinal distress, extreme fatigue as well as chest and muscle pain. It can also lead to spasms in arms and legs.

Viruses in the Coxsackie B family progress to myocarditis or pericarditis, which can result in permanent heart damage or death. Coxsackie B virus infection may also induce aseptic meningitis. As a group, they are the most common cause of unexpected sudden death, and may account for up to 50% of such cases. Models of persistent infection of the heart (https://link.springer.com/chapter/10.1007%2F978-3-540-75546-3_13) and brain (http://jvi.asm.org/content/83/18/9356.short) have been studied in mice.

Immune system
In a mouse model of myocarditis, Coxsackievirus infection was found to upregulate Toll-like receptor 4 on mast cells and macrophages immediately following infection. It also increased numbers of mast cells.

Myalgic Encephalomyelitis
Research has shown that many patients with ME have persistently elevated levels of Coxsackie B IgM or IgG antibodies as well as circulating immune complexes containing viral antigen, indicating the possible presence of a persistent infection. Elevated Coxsackie B antibodies have been found in patients in at least two ME outbreaks. In a retrospective cohort study by Melvin Ramsay and Elizabeth Dowsett, 31% of the patients were found to have elevated enteroviral IgM antibody levels. Sixteen of these patients were retested annually over three years and all showed persistently elevated Coxsackie B neutralizing antibody levels and intermittently positive enteroviral IgM, suggesting a persistent infection was present.

Type 1 diabetes
A study of patients with Type 1 Diabetes found that Coxsackie B4 was found to infect β cells and cause inflammation mediated by natural killer cells.

Testing
In the United States, ARUP Laboratories offers a serum microneutralization assay that is designed to measure the concentration of serum antibodies to six serotypes of the virus; B1 through B6. This specific assay has been shown to be sensitive for detection of chronic infections in ME patients. A persistent fourfold or greater rise in antibody titer is often found in these patients, which is not often found in healthy controls.

A complement fixation assay for Coxsackie B serotypes is available in the United States from LabCorp and Quest Diagnostics, however this specific type of assay has not been found to be sensitive for the chronic infections found in ME patients.

Treatment
There are no approved vaccines or antivirals for Coxsackie viruses. However, preliminary research (often in animal models or in vitro) have been shown various compounds to have potential antiviral effects.