Mean IL-31 levels in serum of dogs with signs of pain tended to be higher than in dogs without signs of pain in the group of dogs with syringomyelia and otitis (group A.2) and in the serum and CSF in the group of dogs with syringomyelia and concomitant neurological disease (group A.3), although the difference was not statistically significant (Fig. 5). Here, IL31 is linked to nervous system disorder.