He uses the HLA tests to get an insight into which neurotoxin might be your particular Achilles' heal.
I'm afraid that isn't true at all. There is no published research showing that any specific HLA haplotypes are associated with specific mold, ME/CFS, or other susceptibilities as Shoemaker clams.
That's a very common combo in people with our illness, so you would not be alone.
The "susceptible" haplotypes listed by Shoemaker are extremely common in every Caucasian. His conclusions are the result of him inappropriately comparing his local patient HLA types against international HLA types, which vary greatly based on ethnic origins.
I can't comment on Shoemaker's other work, but based on the standard of his HLA "research", I wouldn't believe anything he says unless there is a better source verifying it.