Quantitative pp65 antigenemia in the diagnosis of cytomegalovirus disease:: prospective assessment in a cohort of solid organ transplant recipients

Objectives. To assess the accuracy of quantitative pp65 antigenemia (pp65Ag) in the diagnosis of CMV disease, in a cohort of solid-organ transplant recipients. Methods. Prospective observational study during the first 6 months following transplantation, with determination of pp65Ag at weeks 2, 4, 6, 8, 10, 11, 12, 14 and 16. Sensitivity (S), specificity (E), positive and negative predictive values (PPV, NPV), and the optimal cut-off point for diagnosing CMV disease, were determined. Results. The cohort consisted of 35 liver, 26 renal and 12 heart graft recipients. Thirteen (17.2%) were seronegative and received a seropositive graft. Of 583 blood samples, pp65Ag was positive in 109 (18.7%) from 37 patients (51%). Twenty-two patients developed CMV disease (0.3 episodes/patient); gastrointestinal disease was the most frequent (15 episodes), followed by viral syndrome (3 episodes). Patients with positive pp65Ag had a relative risk for CMV disease of 6.19 [IC95% = 1.99-19.04], (P = .0001). Diagnostic values of pp65Ag were: S = 86%, E = 65%, PPV = 51%, NPV = 92%. The cut-off of : 10 infected cells/10(5), at weeks 2, 4, 6 and 8 obtained the best PPV (0, 67, 91 and 54%), and NPV (47, 52, 67 and 50%). Conclusions. In the studied population, the presence of positive pp65Ag was associated with a high risk of developing CMV disease, and the most useful cut-off point for the diagnosis was >= 10 infected cells/10(5). (c) 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved.