A research team evaluated the predominant plasma cell immunoglobulin subclass present in liver biopsies of patients with well-established autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), or primary sclerosing cholangitis (PSC) and evaluated the diagnostic utility of IgM and IgG IHC in this setting. Their study was published in the January 28, 2010, issue of the World Journal of Gastroenterology.

The investigators, from the department of pathology, Columbia University College of Physicians & Surgeons (New York, NY, USA), reported that their research demonstrated that while the plasma cell-rich infiltrates seen in several forms of liver disease predominantly express IgG, PBC seems to be an exception, as most plasma cells in these patients express IgM.

The scientist's data indicated that a predominantly IgM+ plasma cell infiltrate, although not pathognomonic, should strongly support the diagnosis of PBC. The IgM/IgG ratio is especially useful in differentiating PBC from AIH.

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Columbia University College of Physicians & Surgeons