IgG:IgM Ratios of Liver Plasma Cells Reveal Similar Phenotypes of Primary Biliary Cholangitis With and Without Features of Autoimmune Hepatitis

Within the spectrum of autoimmune liver diseases, there are patients who manifest features of more than one disease, which was previously identified as having overlap syndrome1,2 and is now referred to as variant syndromes. The most common variant syndrome is between primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH). Typically, AIH presents with elevated serum immunoglobulin (Ig) G, whereas PBC is associated with elevated serum IgM.3,4 Previous studies have suggested that plasma cells in liver biopsies of AIH patients are predominantly IgG+, whereas in PBC, there is an abundance of IgM+ cells.5,6 We wanted to determine the immunostaining pattern for IgG and IgM of liver plasma cells among Hispanic patients in Los Angeles with features of both PBC-AIH compared with those with PBC or AIH alone.