Multicenter validation study of anti-programmed cell death-1 antibody as a serological marker for type 1 autoimmune hepatitis.

Aim Recently, serum levels of anti-programmed cell death-1 (anti- PD-1) antibodies have been reported to be useful for the discrimination of type 1 autoimmune hepatitis ( AIH) from drug-induced liver injury ( DILI) and to be associated with clinical features of type 1 AIH. This multicenter study aimed to validate the usefulness of serum anti- PD-1 antibody as a serological marker for type 1 AIH. Methods Serum samples before the initiation of corticosteroid treatment were obtained from 71 type 1 AIH patients and 37 DILI patients. Serum levels of anti- PD-1 antibodies were measured by indirect enzyme-linked immunosorbent assay. Results Serum levels of anti- PD-1 antibodies were higher in type 1 AIH patients than in DILI patients ( P < 0.001). The receiver-operator curve analysis showed that serum levels of anti- PD-1 antibodies were useful for the discrimination of type 1 AIH from DILI (area under the curve, 0.80). On the other hand, the multivariate Cox proportional hazard model showed that positivity for serum anti- PD-1 antibody, probable diagnosis based on the revised scoring system proposed by the International Autoimmune Hepatitis Group, and prothrombin activity of less than 60% were associated with the later normalization of serum transaminase levels. During the clinical course, the disease relapsed more frequently in patients positive for serum anti- PD-1 antibody (36% vs 11%). Conclusion This study suggests that serum anti- PD-1 antibody is useful for the diagnosis of type 1 AIH as an auxiliary diagnostic marker, and that serum levels of anti- PD-1 antibodies reflect clinical features of type 1 AIH. [ABSTRACT FROM AUTHOR]