With specific regard to disease subtypes (Figure 7B), it is worth noting that in SPMS patients we found a positive correlation between CD4+/IFNγ+ T lymphocytes and [Ruminococcus] (p = 0.05, tau = 0.427), a well-known mucin-degrading gut microbe to be associated with Crohn's disease as well as other inflammatory disorders (51). Here, CD4 is linked to secondary progressive multiple sclerosis.