In association with the increased percentage of neutrophils presenting high surface CXCR4 expression in SCA patients, the increase in the relative expression of CXCR4 per cell, as demonstrated by mean fluorescence intensity (MFI), was statistically significant on neutrophils from SCA individuals on HU therapy (Fig. 1B). Here, CXCR4 is linked to autosomal dominant cerebellar ataxia.