Question

I’ve been following the post-mortem research that you are involved with and note that there are occasional references to dorsal root ganglionitis being found in some of the nervous system tissues that have been examined so far.

Please could you explain in simple terms what this means. And does this finding confirm that people with ME do actually have inflammation (the -myelitis in encephalomyelitis) in the spinal cord?

Answer

Dorsal root ganglionitis means that there is inflammation (-itis) in a part of the peripheral nervous system called a dorsal root ganglion.

A dorsal root ganglion is a complex bundle of nerve fibres that sits on one of the nerve roots that enter or leave the spinal cord. This is the long nerve that passes down the back inside the bony vertebrae – so it sends and receives information to and from the brain. The nerve roots that enter and leave the spinal cord have two main functions. Incoming information is largely sensory – relating to things like pain and touch – whereas outgoing information is largely concerned with passing on instructions, e.g. creating muscle movements. Dorsal refers to the back of the spinal cord.

A dorsal root ganglion forms part of the sensory nerve root that enters the spinal cord – so it’s involved in processing sensory information. Inflammation in a DRG could therefore result in some of the sensory symptoms that occur in ME – pain, loss of sensation, abnormal sensations (paraesthesiae). And it's interesting to note the presence of dorsal root ganglionitis in an autoimmune condition called Sjögren's Syndrome has been linked to a peripheral neuropathy that is sometimes seen in this condition.

Although ganglionitis means inflammation, and this may well involve infection, the relationship to ME/CFS remains uncertain as this is only a preliminary finding in a small number of post-mortem cases. A number of infections can cause ganglionitis – so it could have been caused by a previous infection that is not even related to ME.

As the DRGs are anatomically outside the spinal cord this finding is not the same as having inflammation in the spinal cord. So, while the finding does support a role for inflammation in the nervous system in ME/CFS, it does not mean that spinal cord inflammation is also present.

• The ME Association has come to a new funding arrangement with the Manchester Brain Bank to continue the research on post-mortem research. More information on this arrangement can be found here.

• There is also a link to a Statement of Intent form that you can add to your Will if you want to donate tissue to medical research.