Effect of administration of immunoglobulin preparations on the results of tests for autoantibodies

Abstract

ABSTRACT Objectives We encountered the case in whom the results of autoantibodies tests became transiently positive after high-dose immunoglobulin therapy and investigated the effect of administration of these preparations on autoantibodies tests in subjects with autoimmune diseases who had received high-dose immunoglobulin therapy. Methods We measured the autoantibodies in residual serum samples after routine clinical testing from eight subjects with autoimmune diseases who had received high-dose immunoglobulin therapy. We also measured the autoantibodies in available immunoglobulin preparations. Results Tests for autoantibodies conducted before and after immunoglobulin therapy revealed a positive conversion of the results for anti-Sjogren’s syndrome antigen A (SS-A) antibody, anti-glutamic acid decarboxylase (GAD) antibody, anti-thyroglobulin (Tg) antibody, and anti-thyroid peroxidase (TPO) antibody. In five cases in which changes in the antibody titres of anti-SS-A antibody after the high-dose immunoglobulin administration, it was found that the titres decreased by about 50% from 10 to 20 days after and the test result became negative 25– 30 days later. Conclusions In patients receiving high-dose immunoglobulin therapy, there appears to be a high likelihood of positive conversion of tests for anti-SS-A antibody, GAD antibody, Tg antibody, and TPO antibody after the treatment, so that cautious interpretation of the results is of importance.