The aim of this study was to investigate the influence of <i>NUDT15 R139C</i> and thiopurine S-methyltransferase (<i>TPMT</i>) on azathioprine (AZA) induced leukopenia in patients with autoimmune hepatitis (AIH) and related cirrhosis.
TPMT phenotyping or genotyping may be advisable before institution of azathioprine therapy in AIH but neither approach invariably predicts response to the drug.