CD1D and systemic sclerosis: We first determined whether Vδ1+ T cells of SSc patients can bind the tetramers of CD1d described in the Section “Materials and Methods.” Briefly cultured PBMC of SSc patients and HC were co-stained with mAb to Vδ1 and with fluorescently labeled native CD1d tetramers (CD1d unbound), CD1d tetramer complexed with a natural ligand, alpha galactosylceramide (PBS-47), or with an OCH derivative of this compound (CD1d-OCH) (27).