CXCR2 and myasthenia gravis: CXCR2 is the only known functional receptor for CXCL5 currently [23] and we found that CXCR2 was highly expressed in primary microglia (Fig. 5a and b, AST vs. MG, p = 0.2053; NEUN vs. MG, p < 0.05; OL vs. MG, p < 0.05).