To investigate the interaction between monocytes and RBCs, we performed an in vitro phagocytosis assay by incubating monocytes separated by CD14-selective magnetic beads and PKH26-labeled RBCs from either HC or SCA patients, followed by quantification of PKH26 signal within monocytes after lysis of adherent RBCs. This evidence concerns the gene CD14 and autosomal dominant cerebellar ataxia.