In contrast, immunoreactivity was observed in (iv) 50% of PBC patients’ peripheral blood mononuclear cells using an interferon-γ release assay [42], and (v) 11.5% demonstrated seroreactivity using an in house ELISA assay with HBRV Env gp52 protein expressed in HEK 293 cells [43]. Here, ERVW-1 is linked to primary biliary cholangitis.