CHOOSING A PP-65 ANTIGENEMIA CUT-OFF AS A DIAGNOSTIC AND ANTIVIRAL TREATMENT CRITERIA FOR CYTOMEGALOVIRUS DISEASE IN RENAL TRANSPLANTATION

Abstract

A98 Introduction: Cytomegalovirus (CMV) infection is a common complication after organ transplantation with high morbidity and mortality among recipients. Objective: To determine antigenemia cut-off with a desirable sensitivity and specificity for the diagnosis of CMV disease. Methods Between January 2000 and December 2001, 203 consecutive renal transplant recipients were retrospectively studied. Weekly measurements of CMV pp65 antigen were performed from the 4th to 12th posttransplantation week. The results were reported as the number of pp65 antigen (Biotest AG) positive cells in 105 granulocytes. Viremia was defined as one positive cell. Mild disease was defined as positive antigenemia and CMV clinical signs. Severe disease was diagnosed whenever there was a positive antigenemia and severe clinical signs with necessity for antiviral therapy. In order to define the best cut-off for each case the Receiver Operator Characteristics Curve (ROC). Results: Latent infection was observed in 92% of the patients before transplantation. Among the 15 seronegative recipients, 5 never presented a positive viremia after transplantation. Primo-infection occurred in 4.9% (10/203) of the patients, clinically presented as severe disease in 70% (7/10) of them. The overall incidence of viremia was 69.5%, and it was more frequent among cadaver recipients (79% × 59%; P=0.02). The incidence of CMV disease was 38.4% (78/203), being 24.6% classified as severe disease, with the need for antiviral therapy. The cut-off of 4 positive cells was chosen for CMV disease diagnosis, with 93% sensitivity and 60% specificity (AUC=0.87). The chosen cut-off for starting antiviral treatment was 10 positive cells, with 92% sensitivity and 70% specificity (AUC=0.90). Conclusion: Regarding the high prevalence of CMV active infection and disease after kidney transplantation, we consider 4 positive cells as an excellent cut-off for diagnosis of CMV disease and 10 positive cells as an indicative for antiviral treatment.