Serum sickness after treatment with rabbit antithymocyte globulin in a heart transplant recipient with previous rabbit exposure.

Antithymocyte globulin (ATG) is a preparation of polyclonal antibodies frequently used to treat acute cellular rejection in organ transplant recipients. Use of rabbit ATG has been associated with serum sickness in liver and kidney transplantation patients previously exposed to rabbits. Here, we report the case of a heart transplantation patient with a history of significant rabbit exposure who had developed migratory diffuse arthralgias 13 days after receiving ATG for acute cellular rejection. Laboratory findings included C-reactive protein elevation, depressed levels of C3 and C4 complement, and strongly positive titers against rabbit immunoglobulin G, all strongly suggestive of serum sickness. To our knowledge, this is the first report of delayed serum sickness related to rabbit ATG after prior rabbit exposure in an adult heart transplantation patient. Early recognition of the symptoms of serum sickness can lead to prompt and appropriate management.