Orchiectomy did not delay onset or severity in BXSB males, while ovariectomy did not exacerbate disease in females, ruling out a hormonal effect [51]. Moreover, consomic studies showed that the BXSB-derived Y chromosome exacerbated disease when combined with either NZW or MRL genetic backgrounds [52, 53]. Thus, an element, termed Y-linked autoimmune accelerator.