CYTOMEGALOVIRUS AND HUMAN-HERPESVIRUS-6 BOTH CAUSE VIRAL DISEASE AFTER RENAL-TRANSPLANTATION

Background. Systemic viral disease after renal transplantation, especi ally after treatment with OKT3 or antithymocyte globulin, has usually been attributed to cytomegalovirus (CMV) infection. Identification of human herpesvirus 6 (HHV6) has raised the possibility that infection o r reactivation of this virus may also occur in the same setting. Metho ds. We thus examined the incidence of CMV and HHV6 infection in a pros pective blinded consecutive series of 30 renal and renal/pancreas tran splant patients, 22 of whom received OKT3, antithymocyte globulin, or both. Results. Clinical diagnosis of a viral syndrome was made in 15 p atients. Three patients with only HHV6 DNA in urine or serum had fever and abnormal liver function but not neutropenia. All five CMV-seroneg ative patients who received positive kidneys developed moderate to sev ere disease with fever and neutropenia but also had HHV6 DNA in urine or serum. Seven CMV-seropositive patients developed disease, mostly af ter OKT3/antithymocyte globulin, but six shed both CMV and HHV6 in uri ne or serum. The simultaneous detection of both HHV6 and CMV DNA in ei ther urine or serum was the strongest predictor of disease (and also t he severity of disease), with an odds ratio of 99.0 (95% confidence in tervals 5.4-1814, P<0.002). Conclusion. Most systemic viral disease af ter renal transplantation may be due to either coinfection or reactiva tion of CMV and HHV6 together. A wider understanding of risk factors f or severe viral disease in this setting may come hom testing for both viruses in all donors and patients in both clinical practice and clini cal trials.