Pathogen discovery in ME

The next presentation was from Professor Mady Hornig (New York, USA). Her focus was on pathogen discovery in ME, in particular in relation to pathogens implicated in brain disorders.  She looked at the role of microbial, immune and toxic stimuli in the development of neuropsychiatric conditions including, autism, PANDAS (paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections), mood disorders and ME. She described a 3-strike hypothesis involving genetics, environment and effects on the foetus. She used the risk of schizophrenia after cannabis exposure as an example. The exposure alone does not lead to the disease—there needs to be genetic susceptibility. In ME, it is unlikely there is a single agent. Many other disorders have an immune generated pathogenesis. In 1957, the autoimmune concept associated with disease was proposed by Witebsky.

In ME, early evidence associated with onset may not be available. There may be direct evidence of effects at infection sites. Replication may cause cell damage, toxins may alter physiology an there may be effects distal to the infection site. Host responses may influence outcomes. Interference with differentiated cell function and molecular mimicry may occur, and there may be long term effects of infection.

Infection may be “hit and run."  In MS there are for example geographic regional effects also. Microbes can condition the immune system via the gastrointestinal tract. Gut microbiota can modulate brain and behaviour, leading for example to effects on sleep and alertness. CNS function depends on a balance between the immune system and stress responses. There is memory dysfunction if the pathways are not operative.

Other studies by Hornig have shown no association between measles virus and autism or bronavirus in schizophrenia. She has however found reduced ileal enzymes, which may lead to failed uptakes of precursors of anti-oxidants. This can lead to oxidative stress. She has several ongoing ME studies relating to this, including looking at the timing of flu and enteroviral infections. She had a brief look back at some of medical history—at how duodenal ulcers were originally thought to be stress related, and were later shown to be due to H.pylori infection.  And quotes from Einstein relating to exam questions—when a student asked why the questions to the current year’s exams were the same as last year, he was told, “but the answers will be different this year “– showing us that medical science is constantly in a state of change.