CTLA4 and Huntington disease: Furthermore, the expression levels of each inhibitory receptor calculated according to the MFI (Fig 1B) were higher for the 2B4 (p<0.01), CTLA-4 (p<0.001) and PD-1 (p<0.0001) inhibitory receptors in CD4+ T cells from CCC compared to those in CD4+ T cells from HD.