Does your mother have an intravaginal sensitivity to semen? Like burning sensation upon contact? Mast cell mediators can induce demyelination, they sit right next to nerves. (MS is also a Th1 dominant condition if I'm not mistaken...I could be wrong). If your POIS is a type IV hypersensitivity or MCAS then it may put you at risk for MS. Diminished Th17 responses could also play a role. I suspect inflammation/weakness in my back/legs respectively are pseudo MS symptoms triggered by MC activation (heat, POIS).