Cytomegalovirus infections in the blood recipient.

Many factors are involved in our ability to understand the complex role of the blood recipient in cytomegalovirus infections. The age factor is an extremely important one. The neonate does not have a fully developed immunological system and is not able to respond as well as the mature individual. The young child has an intact immune system but has had only limited experience with infectious agents. In general, the adult is both experienced and immunologically competent. At the far end of the age scale is the geriatric patient who, though experienced antigenically may not be as immunologically competent as during more vigorous adult years. Another factor is that of health versus disease. A few patients are transfused secondary to trauma; but the majority of patients are acutely ill, chronically ill, or both. The nature of the underlying illness is obviously very important in the recipient's response to blood and agents contained therein. For instance, the Hodgkin's disease patient with a defect in cellular-immune capacity would not be expected to deal as effectively with infectious agents within the transfused blood as would a more normal individual. Also related to the problem of recipient response is the particular treatment regimen given to the patient. Obviously, some recipients are on no therapy at all and thus do not have a compromised ability to react to any blood-borne agents. On the other hand, a number of patients are on steroids, antitumor drugs, and immunosuppressants, or combinations of the above. The latter patients would not be expected to react as effectively as would the normal mature patient. These are just a few of the gross parameters which make studies of recipient response difficult. The complex interaction among the factors involved makes it difficult to generalize and necessitates individualization of each patient involved. Historically, as far as the question of recipient response to specific cytomegalovirus (CMV) transmission by blood is concerned, Kreel et al. (3) in 1960 described a syndrome of fever, splenomegaly, and atypical lymphocytosis with a negative heterophile which occurred after extracorporeal circulation for open-heart surgery. The onset was usually 3 to 7 weeks postperfusion. Kaariainen et al. (2) and later Lang et al. (4) and Foster and Jack (1) implicated CMV both serologically and virologically in this type of patient. They also agreed that blood transfusion was highly suspect as the mechanism of transmission of the virus. It was also appreciated that there was a close resemblance between this postperfusion syndrome and the previously described CMV mononucleosis. Today the postperfusion syndrome is a well described entity which occurs in 3-1 1% of patients undergoing open-heart surgery (4). CMV infection in these recipients, however, is much more common ranging upwards from 33% of