Increased incidence of IgM class smooth muscle antibody in patients after renal transplantation.

Autoantibodies were examined in 70 patients with renal failure, before acceptance on a hemodialysis program, during the program, and up to 3 months after renal transplantation. Smooth muscle antibody (SMA) in the IgM class was detected in 76% of the patients after transplantation compared with 14% before transplantation. This increase was significant at the 5% level. Furthermore, two groups of patients were distinguished on the basis of a 4-fold or greater increase or no demonstrable increase in the titer of IgM SMA after transplantation. Rejection episodes occurred more frequently amongst patients from this former group (67%) compared with the latter group (35%).