COMPARISON OF AN IN-HOUSE DEVELOPED AND TWO COMMERCIAL ASSAYS (LIGHT TM AND CMV BRITETM )FOR QUANTIFICATION OF HUMAN CYTOMEGALOVIRUS PP65-ANTIGENEMIA

 Antigenemia, i.e. detection and quantification of human cytomegalovirus (HCMV) peripheral blood pp65-positive leukocytes, is still one of the two major assays available for diagnosis and monitoring of HCMV infections.Two commercial assays (Light Diagnostics^TM Cytomegalovirus pp65 Antigenemia Immunofluorescence Assay Chemicon, now part of Millipore, Temecula CA, and CMV Brite^TM Turbo, IQ Products, Groningen, The Netherlands) for quantification of human cytomegalovirus (HCMV) pp65-antigenemia were compared with the original in-house developed assay on 300 blood samples from immunocompromised patients. In addition, 264 blood samples were tested for HCMV DNAemia by real-time PCR for comparison.

Results showed a good diagnostic value for both commercial assays, when using the in-house developed method as a reference assay, while PCR showed a lower sensitivity. This apparently unexpected result was due to the dissociation between positive antigenemia and negative DNAemia results, which often occur during ganciclovir treatment. Problems of non-specific cytoplasmic staining were encountered with the CMV Brite^TM assay.

In conclusion, the Light Diagnostics^TM assay provides results comparable to those of the reference assay both in terms of specificity and sensitivity ( number of pp65-positive leukocytes).