[The polymerase chain reaction as a marker of cytomegalovirus infection in heart transplant recipients].

BACKGROUND

To evaluate the usefulness of PCR in peripheral blood leukocytes for the diagnosis of CMV infection and for prognosis of CMV disease in patients with heart transplantation.

PATIENTS AND METHODS

A total of 54 heart transplant recipients included in a protocolized virological follow-up with blood samples (total samples: 594). Mean time of follow-up: 14.8 months (range 1-34 months). We compared a qualitative nested PCR with tube culture (CC), shell vial culture (SV) and pp65 quantitative antigenemia test (AGC).

RESULTS

PCR was the most sensitive test (89.9%) followed by AGC (68.1%), SV (42.6%) and CC (33.4%). Specificity: 80 samples were positive only by PCR, 77 of which form patients with virologically documented CMV active infection, so they were considered as true positives. Three samples were from 2 patients in which the unique positive marker was PCR. If we considered these results as false positive, the calculated specificity was 99.0%. PCR was the first positive marker in 44 out of 45 patients with active CMV infection. In 9 of these patients no other viral marker was positive in the first positive sample, except for PCR. A total of 16 episodes of CMV disease were observed along the study, and a positive PCR result was detected in 15 of them. The remaining patient did not show amplification with the set of primers used in this study, but it gave a positive PCR by amplifying with a different primer pair. Positive predictive value of PCR for CMV disease was low (33.3%). Thus, a positive PCR result did not allow to distinguish between asymptomatic infection and CMV disease.

CONCLUSIONS

In heart transplantation recipients CMV-PCR is a highly sensitive, specific and early marker of CMV infection but its positive predictive value for CMV disease seems unsatisfactory.