Observed dissimilarities between these two cholestatic conditions may suggest that the production of SOCS1 protein by infiltrating lymphocytes is different in PBC (the ratio of SOCS1 to the lymphocyte marker was 0.7 in PBC vs. 1.1 in controls) compared to PSC (the ratio of SOCS1 to the lymphocyte marker was 2.6 vs. 1.1 in controls). Here, SOCS1 is linked to primary biliary cholangitis.