To the Editor.
—I enjoyed reading the editorial entitled "Cytomegalovirus: The Troll of Transplantation," by Henry H. Balfour, Jr, MD, in the Archives (139:279-280, 1979). However, one statement that he makes might stir up a controversy where none need exist. He says that he disagrees with the view that primary cytomegalovirus (CMV) infections are more severe than reinfections. There does not appear to be much doubt that this is indeed the case, if severity includes more severe and frequent morbidity. I have summarized the relevant evidence1 and it need not be repeated here. But the data presented by Dr Balfour himself at least partly support the point. Of eight patients with primary infection, six (75%) had symptomatic disease, while only eight of 22 with reactivation infection had symptomatic disease (36%). The importance of primary infection after renal transplantation was recently extended when it was shown that primary infection is