Although "transplantation pneumonia" has been known since the earliest attempts to transplant human organs, the primary agent responsible for this complication was not suggested until 1964.1,2 The frequent association of cytomegalovirus (CMV) infection with renal allografts is now well known.3,6 Forty to 80% of all patients undergoing transplantation shed CMV during the postoperative period. A higher percentage excrete virus if the recipient is antibody positive to surgery. Of those actively infected, symptoms develop in less than half. Recently, Betts et al5 and Ho and his co-workers6 presented evidence incriminating the transplanted kidney as the source of infection in seronegative recipients. Why some patients tolerate infection so well and others do not has not been completely understood.
In the July issue of the Journal (131:759, 1977), Betts and his colleagues present further prospective data bearing on this question and related issues. They studied 77 kidney recipients (13