A CASE OF GANCICLOVIR-RESISTANT CYTOMEGALOVIRUS (CMV) RETINITIS IN A PATIENT WITH AIDS - LONGITUDINAL MOLECULAR ANALYSIS OF THE CMV VIRAL LOAD AND VIRAL MUTATIONS IN BLOOD COMPARTMENTS

Objectives: To study the temporal relationships between cytomegaloviru s (CMV) viral load and specific UL97 mutations in polymorphonuclear le ukocytes (PMNL) and plasma samples from a patient with AIDS who develo ped ganciclovir-resistant CMV retinitis. Methods: Sequential PMNL and plasma samples were analysed for determination of the CMV viral toad u sing non-molecular methods and a quantitative polymerase chain reactio n (PCR) assay. Screening of the same samples for the most common mutat ions conferring ganciclovir resistance was performed using nested PCR and restriction enzyme analysis. Results: At the time of progression o f CMV retinitis (after 6 months of ganciclovir), a rapid increase in t he CMV DNA load was found in both PMNL and plasma samples. This increa se paralleled the emergence of a specific mutation (V-594) in the same samples and recovery of ganciclovir-resistant blood isolates. In this patient, however, the only tests that substantially predicted the pro gression of CMV disease were the quantitative PCR assay using PMNL and to a lesser extent the pp65 antigenemia assay. Conclusions: Quantitat ive evaluation of the CMV viral load in PMNL using sensitive assays su ch as PCR appears to be a promising approach for monitoring antiviral therapy in subjects with AIDS. In addition, common mutations conferrin g ganciclovir resistance can be detected directly in PMNL and plasma s amples.