The diagnosis of HCMV infection by viral isolation and detection of p65 antigenemia and p72 viremia: a three years experience

The request of CMV infection laboratory diagnosis is steadly rising. In this study we summarize the results of the last 3 years(June 1989 – July 1992). Objectives - a) To evaluate the efficiency of the techniques (cell culture isolation, p72 antigen shell-vial assay and p65 antigen determination) used for detecting CMV in pathological samples; b) to determine the significance of the positivity of the different techniques in sp cimens of polimorphonucLear leucocytes(PMNL). Methods - A total of 3075, specimens (nearly 96% PMNLs) were examined by viral isolation on MRCS cells and p72 assay on mink lung fibroblasts. The p65 assay (antigenemia) was performed on 1354 samples of PMNLs(200.000 cells aliquots). The Mabs Dupont ENP (Dupont) and Clonab CMV (Biotest) were used in indirect immunofluorescence assays(IFA) for p72 and p65 detection respectively. Results – Cell culture and shell-vial isolation methods showed a good agreement. The latter test displayed a quite low sensitivity but the positive results were available within 24 hours as compared to a mean of 10 days needed by cell culture isolation. In the comparison of the performances of the techniques used on PMNL specimens the antigenemia assay, employed from June 1991, showed the highest sensitivity. This test gave a positive result also in 144 samples negative at the other assays. A high number of positive cells(> 50 per 200.000)was found in 47 of 156 CMV positive(positive at least at two assays)samples and in 10 of 144 p65 positive specimens. Discussion - The results regarding the efficiency of p72 and p65 assays are similar to those of the literature, the speed of the response being a major advantage. In our experience it is difficult to define for these tests a trheshold value of the positive cells number indicative of the etiological role of CMV as we examined only symptomatic patients. Other parameters such as the immunological ones should be considered, in particular for AIDS patients.