IL17A and multiple sclerosis: The concentration of IL-17A, which promotes expression of CXCL1 and thereby mobilizes blood-borne neutrophils to sites of infection,34 and has been associated with BBB disruption in multiple sclerosis,35 was also significantly increased in the brains of B. pertussis-infected mice 6 days (∗∗p < 0.01; Figure 2H) and 15 days (Figure S4C) post-challenge.